WEBVTT 00:00:03.000 --> 00:00:13.000 Good afternoon, everybody. We do expect a full class and continue to have folks joining us here at the top of the hour, but I am going to start with some housekeeping rules before we jump into the 00:00:13.000 --> 00:00:20.000 training today's training is being recorded and will be offered on demand through CLUIN for those who are not able to join our live seminar. 00:00:20.000 --> 00:00:25.000 sessions. The Cluhan Training page also has the slides available for download. 00:00:25.000 --> 00:00:29.000 While on Zoom, you can access the Q&A window 00:00:29.000 --> 00:00:37.000 We ask that you use that box to ask questions, make comments, or report any technical problems anytime during today's training. 00:00:37.000 --> 00:00:44.000 We will answer questions in the Q&A window as we go and share the questions and the response with all attendees here today. 00:00:44.000 --> 00:00:50.000 You're welcome to submit your question anonymously if you do not want your name shown to the rest of the audience. 00:00:50.000 --> 00:00:56.000 We will attempt to get to as many questions as we can verbally during our scheduled Q&A breaks as well. 00:00:56.000 --> 00:01:03.000 For those interested in receiving a certificate of completion, it is available at the end of the training by completing the feedback form. 00:01:03.000 --> 00:01:07.000 That was located on the training page that you entered the course today. 00:01:07.000 --> 00:01:09.000 the page 00:01:09.000 --> 00:01:23.000 has the feedback form at the bottom. And as soon as you complete the feedback form in the lower right-hand corner, we ask that you certify that you participated by checking that box and the certificate will be emailed to you. 00:01:23.000 --> 00:01:34.000 Welcome to today's training and introduction to hydrocarbons. My name is Nicole Henderson. I am located in Pittsburgh, Pennsylvania, and will be your moderator today for the class. 00:01:34.000 --> 00:01:45.000 This class was developed as an offspring product of the 2022 ITRC team on effective application of guidance document to hydrocarbons. 00:01:45.000 --> 00:01:56.000 The class is designed to provide a basic overview of hydrocarbon behavior in the subsurface and how to scientifically assess concerns arising from the release of petroleum products in the environment. 00:01:56.000 --> 00:02:03.000 It will highlight key issues that help identify and manage TPH, LMAPL, and PVI risks together. 00:02:03.000 --> 00:02:09.000 This course is based on three separate ITRC guidance documents that address the course content in detail. 00:02:09.000 --> 00:02:14.000 Please make sure you visit the ITRC website and our work to see these guidance documents. 00:02:14.000 --> 00:02:19.000 I will also post the links to these documents after I introduce the trainers. 00:02:19.000 --> 00:02:27.000 Please note that this is the first offering of the class. ITRC will host additional sessions of this class in 2025, including on January 30th. 00:02:27.000 --> 00:02:31.000 Registration for that class will open tomorrow. 00:02:31.000 --> 00:02:36.000 And we have had a very long wait list for today. So we will be moving everybody over to that and 00:02:36.000 --> 00:02:45.000 encouraging you to help us promote the January 30th for any colleagues that were trying to register at this late time 00:02:45.000 --> 00:02:51.000 Interstate technology and regulatory Council is a program of the Environmental Council of States. 00:02:51.000 --> 00:02:57.000 ITRC is a state-led organization composed of members from state agencies, federal government. 00:02:57.000 --> 00:03:01.000 private sector, academia, and community stakeholders. 00:03:01.000 --> 00:03:09.000 Our members participate in technical teams which produce tools, resources, and training courses like the one you are participating in today. 00:03:09.000 --> 00:03:15.000 If you would like to become an ITRC member and see our brand new 2025 teams, we encourage you to visit our website 00:03:15.000 --> 00:03:18.000 and explore joint ITRC at the top. 00:03:18.000 --> 00:03:29.000 Additionally, the ITRC full disclaimer is available on our website. If you plan to use any ITRC materials, we ask that you review the disclaimer in detail and be sure to credit ITRC. 00:03:29.000 --> 00:03:32.000 A TRC is partially funded by the US government. 00:03:32.000 --> 00:03:37.000 An ITRC nor the US government warranty the material nor endorse any specific 00:03:37.000 --> 00:03:40.000 products. 00:03:40.000 --> 00:03:56.000 So in slide four, I am welcoming our trainers for the day, as well as some extra trainers that have joined us in the background to help answer your questions. So we do encourage you to continue to use Q&A pod throughout the training at any time you have a question. 00:03:56.000 --> 00:04:01.000 We have people here to help get through as many responses as we can. 00:04:01.000 --> 00:04:07.000 With that, I am going to hand this over to Tom Fox. 00:04:07.000 --> 00:04:10.000 accidentally change the slides on him. 00:04:10.000 --> 00:04:11.000 Okay. 00:04:11.000 --> 00:04:15.000 And we'll get started. So Tom, tell us a little bit about this course. 00:04:15.000 --> 00:04:20.000 All right. Well, let's see. With the rapid turnover that's occurring in our technical community. 00:04:20.000 --> 00:04:26.000 ITRC has created this webinar to help people adjust into their new job or maybe a position. 00:04:26.000 --> 00:04:29.000 Or maybe you just want a refresher we're not sure 00:04:29.000 --> 00:04:34.000 But today you'll receive a broad overview of the current science regarding petroleum assessment and cleanup. 00:04:34.000 --> 00:04:39.000 You may feel a little bit overwhelmed at the amount of information and the pace we'll be presenting today. 00:04:39.000 --> 00:04:43.000 But keep in mind that this webinar is being recorded. 00:04:43.000 --> 00:04:49.000 And it will be presented again throughout 2025. And the slides will be available in the Clue Insight. 00:04:49.000 --> 00:04:52.000 We have a lot of people with us today. And just to reiterate what Nicole said. 00:04:52.000 --> 00:04:59.000 You can type your questions into the chat so we can answer them either at the breaks or at the end of this presentation. 00:04:59.000 --> 00:05:04.000 So to begin, this training draws from the ITRC guidance that's listed. 00:05:04.000 --> 00:05:09.000 We're going to be covering petroleum vapor intrusion, also known as PVI. 00:05:09.000 --> 00:05:13.000 Light non-aqueous phase liquids, known as LNAP, 00:05:13.000 --> 00:05:16.000 total petroleum hydrocarbons known as TPH, 00:05:16.000 --> 00:05:20.000 But we also want you to be aware of the last offering 00:05:20.000 --> 00:05:25.000 which includes a guide to navigate the first three documents during a risk assessment process. 00:05:25.000 --> 00:05:30.000 And for further information, we really encourage you to visit ITER's website 00:05:30.000 --> 00:05:36.000 and view these documents. 00:05:36.000 --> 00:05:40.000 And I've already malfunctioned. 00:05:40.000 --> 00:05:42.000 All right. 00:05:42.000 --> 00:05:45.000 Where does this training apply? 00:05:45.000 --> 00:05:50.000 This training can be applied very broadly at any number and type of site. 00:05:50.000 --> 00:05:55.000 Some examples include your corner gas station, industrial plants. 00:05:55.000 --> 00:05:57.000 manufacturing facilities 00:05:57.000 --> 00:06:00.000 And even landfills and junkyards. 00:06:00.000 --> 00:06:05.000 very complicated sites may need to involve a team of people with various skills. 00:06:05.000 --> 00:06:08.000 So you may need to have a geologist, perhaps a chemist. 00:06:08.000 --> 00:06:12.000 or even an engineer to successfully complete a project. 00:06:12.000 --> 00:06:17.000 Next. 00:06:17.000 --> 00:06:23.000 So our training goals today are to give you an overview of the key issues and helping identify TPH, 00:06:23.000 --> 00:06:26.000 El Napple and pvi risks together. 00:06:26.000 --> 00:06:31.000 We'll be introducing what's contained in the ITRC guidance documents 00:06:31.000 --> 00:06:34.000 and help you highlight where they overlap. 00:06:34.000 --> 00:06:38.000 We'll be presenting some of the latest science to support best practices 00:06:38.000 --> 00:06:42.000 for the investigation, including conceptual site model development 00:06:42.000 --> 00:06:47.000 risk management and regulation development in your area 00:06:47.000 --> 00:06:50.000 And also be emphasizing the importance of biodegradation 00:06:50.000 --> 00:06:59.000 In risk management decision making. 00:06:59.000 --> 00:07:05.000 Our course outline today consists of three parts. I'll be covering the fundamentals of petroleum hydrocarbons. 00:07:05.000 --> 00:07:08.000 We'll be covering basic petroleum chemistry 00:07:08.000 --> 00:07:12.000 And also review how TPH, LNAPO, and PVI are related. 00:07:12.000 --> 00:07:17.000 In our second portion, we'll be working on building an integrated conceptual site model 00:07:17.000 --> 00:07:20.000 what is a CSM and what's its purpose? 00:07:20.000 --> 00:07:24.000 And when is the CSM complete? 00:07:24.000 --> 00:07:28.000 And finally, in our third section, we'll be identifying and managing risks from petroleum hydrocarbons 00:07:28.000 --> 00:07:31.000 Well, defining these risks based on acute 00:07:31.000 --> 00:07:39.000 saturation, composition, or aesthetic concerns. 00:07:39.000 --> 00:07:45.000 So let's get right into the fundamentals of petroleum hydrocarbons. 00:07:45.000 --> 00:07:51.000 To better understand the chemistry of petroleum products, we must first understand how to refine from crude oil. 00:07:51.000 --> 00:07:53.000 which is depicted in this animation. 00:07:53.000 --> 00:07:56.000 Here, crude oil is shown on the left. 00:07:56.000 --> 00:07:58.000 where it is superheated in a boiler 00:07:58.000 --> 00:08:03.000 and becomes vapor. This vapor is then sent through a distillation column. 00:08:03.000 --> 00:08:07.000 where the vapor turns back into liquid at various temperatures. 00:08:07.000 --> 00:08:12.000 this distillation process separates the crude oil into hydrocarbon mixtures by weight 00:08:12.000 --> 00:08:17.000 which is shown by the number of carbon atoms on the right side of this animation. 00:08:17.000 --> 00:08:22.000 compounds with only a few compounds with only a few carbon atoms 00:08:22.000 --> 00:08:25.000 are referred to as later end compounds 00:08:25.000 --> 00:08:27.000 like bottled gas or gasoline. 00:08:27.000 --> 00:08:30.000 And these are distilled at much lower temperatures 00:08:30.000 --> 00:08:34.000 than the middle distillates like kerosene and diesel fuel. 00:08:34.000 --> 00:08:39.000 Oils and tars will settle into the bottom of the distillation column 00:08:39.000 --> 00:08:43.000 And TPH analyses help measure petroleum hydrocarbons that are present 00:08:43.000 --> 00:08:52.000 In El Napple, zorb, dissolved in vapor phases. 00:08:52.000 --> 00:08:55.000 Although crude oil has been separated by weight. 00:08:55.000 --> 00:09:00.000 Each of the refined petroleum products is still a complex mixture of thousands of compounds. 00:09:00.000 --> 00:09:05.000 This chart shows the typical carbon ranges for several types of refined fuels and oils. 00:09:05.000 --> 00:09:09.000 You can see that gasoline has a range of 4 to 12 carbon atoms. 00:09:09.000 --> 00:09:13.000 Well, diesel fuel has a range of 8 to 24 carbon atoms. 00:09:13.000 --> 00:09:18.000 Heavier oils can range up to 20 to over 30 carbon atoms. 00:09:18.000 --> 00:09:27.000 Well, crude oil can span up to 40 carbon atoms. 00:09:27.000 --> 00:09:33.000 Once petroleum is released to the environment, we refer to the liquid product as LLAP. 00:09:33.000 --> 00:09:38.000 El Napple is specifically defined as a light, non-aqueous phase liquid 00:09:38.000 --> 00:09:40.000 that has a density less than water 00:09:40.000 --> 00:09:42.000 and is immiscible with water. 00:09:42.000 --> 00:09:50.000 This is typically associated with petroleum products, although other oils are also elm apples such as vegetable oil. 00:09:50.000 --> 00:09:54.000 Elmapple can become the source of TPH and PVI 00:09:54.000 --> 00:10:00.000 It can also be very difficult to assess and recover once it's released to the subsurface, as many of you know. 00:10:00.000 --> 00:10:05.000 El Napole itself contains more than 99% of the hydrocarbon source mass 00:10:05.000 --> 00:10:09.000 And it will often act as a long-term source of vapor 00:10:09.000 --> 00:10:15.000 groundwater and soil contamination. 00:10:15.000 --> 00:10:20.000 So let's talk a little bit about how and where LNAPL occurs. 00:10:20.000 --> 00:10:25.000 So on the left-hand side is an illustration of an LNAPLE release 00:10:25.000 --> 00:10:29.000 And during a petroleum release, L-Napple displaces the soil pores 00:10:29.000 --> 00:10:34.000 in the Vedo zone by overcoming the resistance to flow 00:10:34.000 --> 00:10:37.000 and displacing the air that's in the pores. 00:10:37.000 --> 00:10:41.000 And it does this through various poor connections, also known as poor throats. 00:10:41.000 --> 00:10:43.000 As the LNAPLE moves downward. 00:10:43.000 --> 00:10:47.000 encounters the capillary zone in groundwater in most cases 00:10:47.000 --> 00:10:52.000 And then it has to also displace water from the pores, which is a bit more difficult 00:10:52.000 --> 00:10:54.000 than simply moving air. 00:10:54.000 --> 00:10:56.000 The young apple buoyancy 00:10:56.000 --> 00:10:59.000 in the water limits downward movement 00:10:59.000 --> 00:11:04.000 An excess LNAPA will now travel sideways off to the right in this illustration 00:11:04.000 --> 00:11:09.000 creating a plume, but always leaving some behind, kind of like a snail's trail. 00:11:09.000 --> 00:11:13.000 Some elm apple dissolves to create a groundwater plume 00:11:13.000 --> 00:11:18.000 In some cases far enough away from the source mass, you'll have impacted groundwater 00:11:18.000 --> 00:11:22.000 with no elm apple visible. 00:11:22.000 --> 00:11:28.000 Now to the right side. Oh, I'm sorry. One thing I want to mention is it's really important to note that this is uh 00:11:28.000 --> 00:11:33.000 Not a fracture flow situation. This is a textbook illustration of most porous materials. 00:11:33.000 --> 00:11:37.000 We don't have time to get into fracture flow, I'm afraid. 00:11:37.000 --> 00:11:40.000 So on the right-hand side, let's talk about LNAP partition 00:11:40.000 --> 00:11:46.000 partitioning. El Napo exists in four phases in the environment. It'll exist as El Napple 00:11:46.000 --> 00:11:50.000 but also dissolve out his constituents absorb the soil surfaces 00:11:50.000 --> 00:11:56.000 dissolved in water and volatilized air now all that, as I've said is 00:11:56.000 --> 00:11:59.000 a very small percentage is shown as this yellow strip on the slide. 00:11:59.000 --> 00:12:03.000 As part of this bar graph. 00:12:03.000 --> 00:12:09.000 99% stays as El Napple and very little of the LNAPLE components transfer to other media. 00:12:09.000 --> 00:12:13.000 Some LNAPLE may reach groundwater, and if there is enough. 00:12:13.000 --> 00:12:15.000 become mobile and even migrate 00:12:15.000 --> 00:12:18.000 However, only some of this elm apple can be recovered. 00:12:18.000 --> 00:12:26.000 regarding recovery, keep in mind that oil companies have spent billions of dollars trying to recover liquid petroleum from the ground. 00:12:26.000 --> 00:12:29.000 And at most, only about one third of what's there can be recovered 00:12:29.000 --> 00:12:34.000 And in the environmental industry, I don't think we're going to do much better. 00:12:34.000 --> 00:12:38.000 most el napple becomes residual or stuck in the soil pores 00:12:38.000 --> 00:12:41.000 where it can become a long-term contamination source. 00:12:41.000 --> 00:12:44.000 This is why excavation is so useful. 00:12:44.000 --> 00:12:47.000 you're actually removing ln apple trapped in the soil pores. 00:12:47.000 --> 00:12:50.000 Each of these phases creates their own set of risks 00:12:50.000 --> 00:13:01.000 And we address those risks using different technologies or strategies that we'll be talking about later. 00:13:01.000 --> 00:13:03.000 So what is TPH? 00:13:03.000 --> 00:13:08.000 One indicator of ill and apple content in media, both soil, water, and vapor. 00:13:08.000 --> 00:13:13.000 is TPH. ITRC defines TPH as hydrocarbons only. 00:13:13.000 --> 00:13:20.000 which are compounds made up of hydrogen and carbon, can be joined into chains known as aliphatic hydrocarbons. 00:13:20.000 --> 00:13:23.000 Or rings known as aromatic hydrocarbons. 00:13:23.000 --> 00:13:29.000 Once TPH is in the environment, it can migrate from one media to another through partitioning. 00:13:29.000 --> 00:13:32.000 For example, TPH from a release area 00:13:32.000 --> 00:13:34.000 could dissolve into soil poor water 00:13:34.000 --> 00:13:36.000 and leached downward into groundwater. 00:13:36.000 --> 00:13:40.000 Once in groundwater, TPH volatilizes the soil vapor 00:13:40.000 --> 00:13:46.000 And it may emanate up through the unsaturated zone and intrude into buildings and indoor air. 00:13:46.000 --> 00:13:51.000 Therefore, it's really important to understand TPH source and migration pathways 00:13:51.000 --> 00:13:57.000 And when you're selecting the appropriate analytical methods and media for your site investigation, and very often these methods 00:13:57.000 --> 00:14:11.000 are dictated by the local regulatory agency. 00:14:11.000 --> 00:14:21.000 CSAT is the TPH saturation concentration that indicates the maximum LNAPL that may be present in soil, either in pores or fractures. 00:14:21.000 --> 00:14:26.000 CSAT will vary by both the fuel type and the soil type. 00:14:26.000 --> 00:14:29.000 Elmapple may or may not be present in the monitoring well. 00:14:29.000 --> 00:14:35.000 And we'll discuss LNAPO mobility and the concerns it can create a little later in this presentation. 00:14:35.000 --> 00:14:39.000 Now that we understand the universe of compounds present in refined products. 00:14:39.000 --> 00:14:42.000 How do we measure TPH in different environmental media? 00:14:42.000 --> 00:14:46.000 The answer lies in the TPH analytical method that is selected. 00:14:46.000 --> 00:14:49.000 I really want to stress this point. 00:14:49.000 --> 00:14:52.000 that the analytical method defines TPH 00:14:52.000 --> 00:14:55.000 And it provides an approximate concentration 00:14:55.000 --> 00:14:58.000 of the total hydrocarbons in each media. 00:14:58.000 --> 00:15:01.000 Ironically, TPH is not necessarily total 00:15:01.000 --> 00:15:04.000 It's not necessarily all from petroleum. 00:15:04.000 --> 00:15:06.000 And it's not necessarily all hydrocarbons. 00:15:06.000 --> 00:15:19.000 And we'll talk more on this later. 00:15:19.000 --> 00:15:23.000 What does petroleum vapor intrusion or PVI? 00:15:23.000 --> 00:15:29.000 Basically, PVI is the migration of hydrocarbon vapors from petroleum contaminants in the subsurface 00:15:29.000 --> 00:15:32.000 into overlying buildings or utilities 00:15:32.000 --> 00:15:35.000 which causes a potential public health concern. 00:15:35.000 --> 00:15:38.000 It's often a key risk driver at petroleum release sites 00:15:38.000 --> 00:15:41.000 driving environmental cleanup. 00:15:41.000 --> 00:15:44.000 It's strongly influenced by the source type. 00:15:44.000 --> 00:15:48.000 both the fuel and whether it's an LNAPLE or dissolve phases. 00:15:48.000 --> 00:15:52.000 And it also differs from chlorinated vapor intrusion. 00:15:52.000 --> 00:15:57.000 Petroleum vapors are highly susceptible to biodegradation. 00:15:57.000 --> 00:16:00.000 But they can also create certain acute risks such as explosion hazards. 00:16:00.000 --> 00:16:11.000 from the production of methane during biodegradation. 00:16:11.000 --> 00:16:13.000 Let's see, I believe. 00:16:13.000 --> 00:16:16.000 having trouble getting my slide to advance Nicole. Oh, there we go. 00:16:16.000 --> 00:16:20.000 And at this point, I want to hand it off to Matt Lavas, who's going to introduce you to 00:16:20.000 --> 00:16:23.000 building a conceptual site model 00:16:23.000 --> 00:16:27.000 Thanks and Matt. I'm pulling up a quick poll while you guys transition. 00:16:27.000 --> 00:16:30.000 Just to get a sense of our audience today. 00:16:30.000 --> 00:16:38.000 I will leave that open line. 00:16:38.000 --> 00:16:42.000 Let me know when you want me to go. 00:16:42.000 --> 00:16:47.000 You're all set. 00:16:47.000 --> 00:16:52.000 I just have a couple more people filling in the poll. I'm going to share the results, Matt. 00:16:52.000 --> 00:16:56.000 And then we'll let you get started. 00:16:56.000 --> 00:16:57.000 A lot of people coming in. 00:16:57.000 --> 00:17:01.000 All right. Thanks and welcome everyone. So the next few slides here. 00:17:01.000 --> 00:17:10.000 We'll talk about the conceptual site model, and it's arguably the most important element of any hydrocarbon assessment. 00:17:10.000 --> 00:17:12.000 in terms of 00:17:12.000 --> 00:17:18.000 really understanding what your risks are and then how to manage those risks. 00:17:18.000 --> 00:17:31.000 So a CSM is going to be used then to identify your potential sources for hydrocarbons, your pathways for how those hydrocarbons are moving in the subsurface, and then 00:17:31.000 --> 00:17:34.000 your receptors. 00:17:34.000 --> 00:17:39.000 for a current and unreasonably anticipated future site conditions so 00:17:39.000 --> 00:17:50.000 It's only when we have that linkage between the source pathway and receptor when we have a risk. But that CSM has to come away with 00:17:50.000 --> 00:17:55.000 that information has to be able to identify when those risks are present. 00:17:55.000 --> 00:18:02.000 It's also going to be used to define your LNAPL concerns, goals, and objectives. That gets into, okay. 00:18:02.000 --> 00:18:07.000 starting to understand if you do have a risk, how to manage that risk. 00:18:07.000 --> 00:18:19.000 So if we step back, the CSM is really around identifying risks and then how to manage those risks. So it's supporting some of the key decision making, whether it comes in as the site screening level. 00:18:19.000 --> 00:18:25.000 Whether it's telling us we need further data collection or how to manage those risks. 00:18:25.000 --> 00:18:33.000 So that's CSM. It's going to be presented primarily as text with some kind of supporting diagrams and they could be 00:18:33.000 --> 00:18:47.000 plan views could be cross sections, that sort of thing. And it's constantly updated as you collect new information. So you may start out with an initial CSM, but find you don't have the information 00:18:47.000 --> 00:18:52.000 available to answer all these questions around site screening. You need some more data. 00:18:52.000 --> 00:18:58.000 and more information. So you're going to keep updating that CSM as you go along to finally, again. 00:18:58.000 --> 00:19:06.000 answer some questions about how to manage any risks that are present and get yourself to closure. 00:19:06.000 --> 00:19:08.000 So… 00:19:08.000 --> 00:19:24.000 I was just jumping around a little. So here's a depiction of a general CSM or what might be contained in one where we've got an above ground storage tank here on the left side and AST where we've lost some 00:19:24.000 --> 00:19:29.000 Petroleum hydrocarbons into the subsurface and some of it has 00:19:29.000 --> 00:19:34.000 spilled out on the land surface. And what you're seeing here for that 00:19:34.000 --> 00:19:37.000 hydrocarbon. 00:19:37.000 --> 00:19:47.000 is some associated pathways. And we might have one that's associated here with a building type receptor where you've got inhalation. 00:19:47.000 --> 00:20:01.000 exposure. You may have exposure to the surface spill either directly from dermal contact or ingestion of those surface soils or inhalation of vapors from the surface soils. 00:20:01.000 --> 00:20:03.000 Someone might have a well present 00:20:03.000 --> 00:20:07.000 which represents another ingestion pathway. 00:20:07.000 --> 00:20:14.000 For drinking water. And then if that hydrocarbon has made its way into surface water. 00:20:14.000 --> 00:20:21.000 against someone who might come in contact with that surface water swimming, you've got ingestion, dermal inhalation. 00:20:21.000 --> 00:20:24.000 as well as ecological risk. 00:20:24.000 --> 00:20:32.000 So they're going to change depending on where that hydrocarbon is and what media is represented 00:20:32.000 --> 00:20:35.000 where that hydrocarbon is in which media. 00:20:35.000 --> 00:20:47.000 Now, what we've also superimposed here goes back to that earlier slide Tom was presenting here, showing you a little bit about where that hydrocarbon mass is going to be located. And if we start here. 00:20:47.000 --> 00:20:55.000 And this pie chart that's mainly black. So if we're in that area where El Napple is present, again, most of that hydrocarbon is going to be 00:20:55.000 --> 00:21:02.000 present within the LNAPA phase. Very little in the air, vapor, water, absorb phases. 00:21:02.000 --> 00:21:10.000 But if we step outside of where El Napple might be present in the subsurface, let's say we're in the Vedo zone or we're in groundwater. 00:21:10.000 --> 00:21:24.000 Well, then that hydrocarbon is going to be distributed primarily amongst the air, water, and sorb phases. If we're in the Vedo zone or just the water absorbed phases in the groundwater. And that distribution is going to change depending on 00:21:24.000 --> 00:21:29.000 what hydrocarbon we're looking at or what mixture of hydrocarbons were. 00:21:29.000 --> 00:21:35.000 we're looking at. Now, ITRC and its hydrocarbons 00:21:35.000 --> 00:21:40.000 training module has put together this handy checklist 00:21:40.000 --> 00:21:49.000 that helps one work their way through the development of a CSM. And so it has some steps in here. 00:21:49.000 --> 00:22:00.000 and references to resources within all of the various tech regs, LNAPLE, TPH, PVI, where you can find out additional information about 00:22:00.000 --> 00:22:05.000 how to prepare and develop that conceptual site model. 00:22:05.000 --> 00:22:15.000 Now, not all site models are going to, there's conceptual site models are going to be created equal, and that's important to understand here that they should be targeted or tailored to the site conditions 00:22:15.000 --> 00:22:22.000 And really just about identifying, getting the information to identify and manage those potential risks. 00:22:22.000 --> 00:22:25.000 So say, for example, we're at a complex hydro 00:22:25.000 --> 00:22:29.000 stratigraphic site where we've got, I don't know, layered sands and 00:22:29.000 --> 00:22:36.000 And glaze or maybe it's fractured rock, but a highly complex hydrostratographic 00:22:36.000 --> 00:22:45.000 subsurface. Well, then, yeah, it may take a lot more effort and cost to try and understand where are my sources and 00:22:45.000 --> 00:22:54.000 How are those hydrocarbons moving maybe between a source and a receptor? So bear that in mind as well as 00:22:54.000 --> 00:22:57.000 we might have to 00:22:57.000 --> 00:23:04.000 Spend more time on getting it right, getting that CSM right. So that's going to require more investment. 00:23:04.000 --> 00:23:16.000 At sites where we've got maybe sensitive receptors nearby or there's reputational risks or this potentially is a community issue or we've got hydrocarbons that are 00:23:16.000 --> 00:23:19.000 that are highly toxic. 00:23:19.000 --> 00:23:28.000 In that regard, we've got to get it right. So those are the sites where we're going to invest more in the CSM. 00:23:28.000 --> 00:23:30.000 But then there are sites where maybe we 00:23:30.000 --> 00:23:44.000 don't have to invest that much in the CSM because maybe it's a gas station located in an urban environment where there's no drinking water wells nearby. No one's potentially getting exposed. 00:23:44.000 --> 00:23:53.000 We can live with more uncertainty in our CSM, and I'll have you focus here in this middle box here. So long as we have 00:23:53.000 --> 00:24:00.000 enough information where we can bound that uncertainty or we're okay with having that uncertainty we can say we're 00:24:00.000 --> 00:24:04.000 done with that CSM because conditions are going to change on a site. 00:24:04.000 --> 00:24:11.000 You know, you may have seasonal changes in concentrations or distributions of hydrocarbon 00:24:11.000 --> 00:24:24.000 Yeah, maybe because of water table fluctuations, you get changes in the thickness of El Napple that might be present in a well. But if it's not changing the risk profile at the site. 00:24:24.000 --> 00:24:29.000 And maybe you're fine with your CSM and you can move on and you have the information needed to 00:24:29.000 --> 00:24:34.000 to make all the key questions, answer the key questions. 00:24:34.000 --> 00:24:49.000 And then if we just focus on the left side, we certainly have to have that information to be able to understand where our sources are, the pathways, and potential to impact current future receptors. And lastly, on the right side here. 00:24:49.000 --> 00:24:52.000 making sure if we do have a risk 00:24:52.000 --> 00:25:02.000 Do I have sufficient information to be able to identify my LNAPA goals, concerns, and objectives? We'll talk about these more in the next section. 00:25:02.000 --> 00:25:05.000 So that gets around the risk management part. 00:25:05.000 --> 00:25:10.000 And with that, I'm going to turn it over to 00:25:10.000 --> 00:25:19.000 to Tom, but I think a question just came in. Can Matt answer a question about where hydrocarbon vapors are primarily sourced, groundwater or Nelnapple? 00:25:19.000 --> 00:25:26.000 We are going to address that question later on in the webinar. 00:25:26.000 --> 00:25:37.000 But if we think about that just high level, hydrocarbon vapors are primarily going to be sourced from elm apple. Elm apple is going to be the primary 00:25:37.000 --> 00:25:41.000 driver then for petroleum vapor intrusion. 00:25:41.000 --> 00:25:45.000 Okay. With that, Tom, over to you. 00:25:45.000 --> 00:25:52.000 All right. Thanks, Matt. So Matt has kind of covered through this flow chart, working through your initial conceptual site model. 00:25:52.000 --> 00:25:54.000 doing your site screening. 00:25:54.000 --> 00:25:59.000 fine-tuning your conceptual site model to the point where now you can manage your site. 00:25:59.000 --> 00:26:05.000 And we're going to be looking then to refine your remedial goals and objectives. 00:26:05.000 --> 00:26:09.000 and implement your remediation to hopefully get you to the no further action 00:26:09.000 --> 00:26:12.000 site closure box that's shown on this flow chart. 00:26:12.000 --> 00:26:17.000 So let's look briefly at some of the exposure risks that petroleum hydrocarbons create 00:26:17.000 --> 00:26:24.000 And how those risks are created. 00:26:24.000 --> 00:26:28.000 Okay, so from the time of the release, you've been creating a csm 00:26:28.000 --> 00:26:33.000 And from that, you're identifying what concerns a release presents. 00:26:33.000 --> 00:26:35.000 And some of these examples are 00:26:35.000 --> 00:26:37.000 And I'll bring these out here. 00:26:37.000 --> 00:26:42.000 or that we run into acute risks, which are risks to health and safety. 00:26:42.000 --> 00:26:47.000 And that would be things like fire explosion or acute risks. 00:26:47.000 --> 00:26:51.000 L-napple then becomes a saturation risk 00:26:51.000 --> 00:26:57.000 And we have to be concerned about migrating Elmapple, which would expand the area of concern. 00:26:57.000 --> 00:27:00.000 We also then look at composition. 00:27:00.000 --> 00:27:03.000 And sometimes in conjunction with saturation concerns 00:27:03.000 --> 00:27:07.000 where we're looking at the dissolution of the El Nappo into other media. 00:27:07.000 --> 00:27:12.000 such as into vapor we're dividing out in TPH fractions 00:27:12.000 --> 00:27:14.000 and dissolving into groundwater. 00:27:14.000 --> 00:27:17.000 And this is usually defined by the toxicity 00:27:17.000 --> 00:27:21.000 of the compounds that are dissolved in these other media. 00:27:21.000 --> 00:27:24.000 And a lot of you are probably mostly wrestling with these issues. 00:27:24.000 --> 00:27:28.000 And finally, we can get into some aesthetic concerns 00:27:28.000 --> 00:27:33.000 And these might involve sheens that appear at the edges of stream banks or other 00:27:33.000 --> 00:27:38.000 water bodies. We also worry about aesthetics, whether these are staining and odor 00:27:38.000 --> 00:27:41.000 or even geotechnical concerns that the El Napple might 00:27:41.000 --> 00:27:49.000 prevent the soil from being used for proper building purposes. 00:27:49.000 --> 00:27:53.000 So we're going to go through some of the remedial terminology that we're going to be using. 00:27:53.000 --> 00:27:55.000 Apart from acute and emergency risks. 00:27:55.000 --> 00:28:01.000 which are addressed immediately, ITRC identifies three remedial concerns for LNAP. 00:28:01.000 --> 00:28:07.000 The saturation concerns are derived from the amount and behavior of L-napple in the formation 00:28:07.000 --> 00:28:11.000 We'll talk about this a little bit more in the next slide. 00:28:11.000 --> 00:28:15.000 composition concerns are derived from the chemistry of the yellen apple. 00:28:15.000 --> 00:28:17.000 such as those associated with vapors 00:28:17.000 --> 00:28:20.000 groundwater and soil contact. 00:28:20.000 --> 00:28:23.000 And then the other aesthetic issues that I've mentioned 00:28:23.000 --> 00:28:25.000 that you need to address. 00:28:25.000 --> 00:28:31.000 The ITRC LNAPL 3 guidance established a decision process to identify ill-napple concerns 00:28:31.000 --> 00:28:35.000 And to us to help you establish remedial goals, objectives. 00:28:35.000 --> 00:28:41.000 and select remedial technologies. And I really encourage you to look at the LNAPL 3 document online. 00:28:41.000 --> 00:28:45.000 First, bone apple concerns are verified using threshold metrics 00:28:45.000 --> 00:28:48.000 They're usually detailed in the guidance. 00:28:48.000 --> 00:28:51.000 either with ITRC or in your state guidance. 00:28:51.000 --> 00:28:57.000 There are some perceived concerns that may be eliminated. 00:28:57.000 --> 00:29:00.000 Next, remedial goals are established, which translate 00:29:00.000 --> 00:29:02.000 into an elen apple concern 00:29:02.000 --> 00:29:05.000 having a measurable LNAP outcome 00:29:05.000 --> 00:29:08.000 Each concern may have its own goal. 00:29:08.000 --> 00:29:11.000 or sometimes multiple concerns may share a common goal. 00:29:11.000 --> 00:29:14.000 And that is that you're trying to maybe 00:29:14.000 --> 00:29:18.000 reduce your contaminants of concern to below cleanup levels. 00:29:18.000 --> 00:29:20.000 And finally, your remedial objective 00:29:20.000 --> 00:29:24.000 describes the goals will be how the goals will be accomplished 00:29:24.000 --> 00:29:28.000 And these are linked to the technologies that you choose. 00:29:28.000 --> 00:29:30.000 So you may target volatiles 00:29:30.000 --> 00:29:33.000 using soil vapor extraction, for example. 00:29:33.000 --> 00:29:36.000 and set a set of metrics to judge 00:29:36.000 --> 00:29:43.000 how far that system can carry you before you may need to move to a different technology or strategy. 00:29:43.000 --> 00:29:52.000 However, regulations on how to identify and address concerns can vary by state, and we want to emphasize that this is based on risk-based corrective actions. 00:29:52.000 --> 00:30:00.000 that may vary in your state or not exist at all. 00:30:00.000 --> 00:30:05.000 Tell knuckle sites typically exist under three conditions presented on this slide. 00:30:05.000 --> 00:30:08.000 site one at the top 00:30:08.000 --> 00:30:17.000 has a new release. Ilnapple saturations and gradients are very high and the Ilnapple footprint is expanding. In other words, the El Napple is migrating. 00:30:17.000 --> 00:30:24.000 The immediate concern here is a saturation concern because the El Napo area can expand to impact more receptors. 00:30:24.000 --> 00:30:28.000 El Napple migration should be mitigated immediately. 00:30:28.000 --> 00:30:34.000 However, it's also important to understand compositional concerns may also be present at this time. 00:30:34.000 --> 00:30:39.000 We'll talk about how to mitigate LNAPO a little later in this presentation. 00:30:39.000 --> 00:30:42.000 At the second site in the middle. 00:30:42.000 --> 00:30:45.000 at most sites, Elnapol was observed in wells 00:30:45.000 --> 00:30:48.000 And the El Naple footprint is stable. 00:30:48.000 --> 00:30:50.000 We call this mobile L-NAP. 00:30:50.000 --> 00:30:53.000 It may move in and out of the well screen 00:30:53.000 --> 00:30:56.000 But the El Napple body is not migrating. 00:30:56.000 --> 00:30:58.000 The LNAP will be recoverable. 00:30:58.000 --> 00:31:03.000 But the primary concern to evaluate at this point are associated with composition 00:31:03.000 --> 00:31:08.000 the composition in the soil, vapor in the dissolved concentrations. 00:31:08.000 --> 00:31:11.000 Belnapple recovery may be a component of the remedy 00:31:11.000 --> 00:31:14.000 It may even be a regulatory requirement 00:31:14.000 --> 00:31:19.000 But compositional concerns will drive the health and safety risks. 00:31:19.000 --> 00:31:23.000 It's site three on the bottom. El Napple is not observed in wells. 00:31:23.000 --> 00:31:26.000 But LNAP was trapped in the pore space. 00:31:26.000 --> 00:31:28.000 known as residual LNAP, 00:31:28.000 --> 00:31:34.000 The residual LNAPA will continue to be a long-term source of compositional concerns. 00:31:34.000 --> 00:31:41.000 In summary here, sites one and two look a lot the same. You can see El Napple is visible in the wells. 00:31:41.000 --> 00:31:45.000 But sites two and three behave the same with respect to their associated 00:31:45.000 --> 00:31:53.000 compositional risk profiles. 00:31:53.000 --> 00:31:59.000 So let's look a little bit further at how to contrast saturation and compositional goals. 00:31:59.000 --> 00:32:03.000 and why recovery may or may not be really necessary at your site. 00:32:03.000 --> 00:32:08.000 the composition of the El Napa was the main risk driver on most petroleum sites. 00:32:08.000 --> 00:32:13.000 So let's focus on how we can be able to change the compositional risks we face. 00:32:13.000 --> 00:32:16.000 Why is composition change so important? 00:32:16.000 --> 00:32:20.000 Research has shown that a reduction in saturation 00:32:20.000 --> 00:32:22.000 In other words, the LNAPLE mass 00:32:22.000 --> 00:32:25.000 has little effect on the dissolved concentration 00:32:25.000 --> 00:32:29.000 Unless almost all the elen apple from the source is removed. 00:32:29.000 --> 00:32:32.000 It's more effective to target constituents of concern 00:32:32.000 --> 00:32:35.000 that are a small fraction of the total L-napple. 00:32:35.000 --> 00:32:40.000 In this situation, you can see on the chart that if we move from point a 00:32:40.000 --> 00:32:42.000 to point B by removing 00:32:42.000 --> 00:32:51.000 elm apple, we really don't change the concentration of benzene that's present in the groundwater. 00:32:51.000 --> 00:32:59.000 So using a phase change remedial technology, which we'll talk about later, is to reduce the benzene concentration in groundwater 00:32:59.000 --> 00:33:01.000 from a to c 00:33:01.000 --> 00:33:04.000 will get us to our closure goal that much more quicker 00:33:04.000 --> 00:33:10.000 and reduce risk by recovering some, but maybe not all of the bulk gasoline. 00:33:10.000 --> 00:33:15.000 Now let's go through seven key points that we want you to understand about El Napple 00:33:15.000 --> 00:33:17.000 And Steve will kick off the first one. 00:33:17.000 --> 00:33:24.000 Steve? 00:33:24.000 --> 00:33:29.000 Thank you, Tom. 00:33:29.000 --> 00:33:35.000 Just waiting for… 00:33:35.000 --> 00:33:46.000 Control. 00:33:46.000 --> 00:33:52.000 Nope, that's you. That wasn't me. 00:33:52.000 --> 00:33:54.000 Sorry, RF, got control. 00:33:54.000 --> 00:34:00.000 All right. Yeah. Thanks, Tom. I'm going to start talking about some of those key messages. We're going to start with… 00:34:00.000 --> 00:34:05.000 Elmap on a well does not mean that LNAP is migrating. 00:34:05.000 --> 00:34:12.000 In fact, most NAPPL bodies stabilize relatively quickly. And at most petroleum sites. 00:34:12.000 --> 00:34:16.000 The elen apple plume is likely stable. 00:34:16.000 --> 00:34:22.000 This is a cross-sectional view of an elm apple plume focused on the elm apple gradient over time. 00:34:22.000 --> 00:34:33.000 The LNAPLE gradient are the primary driving force for migration, but the gradient is going to dissipate over time for a finite release of El Napol as shown on this slide. 00:34:33.000 --> 00:34:40.000 The photos are from a sand tank experiment with the El Napple dyed red. The left slide. 00:34:40.000 --> 00:34:48.000 The left side is shortly after the release reaches the water table and the right side is some time after the release was abated. 00:34:48.000 --> 00:34:55.000 the illustrations, the illustrations above are a graphical depiction of the sand tank pictures below. 00:34:55.000 --> 00:35:05.000 The LNAPLE gradients can be measured as the altitude of the air Napple interface in the monitor wells. The white dashed line represents the LNAPL gradient on the photos. 00:35:05.000 --> 00:35:08.000 And the red line in the illustration. 00:35:08.000 --> 00:35:13.000 As you can see, the gradient decreases as the L and Apple body expands. 00:35:13.000 --> 00:35:19.000 The key factor that stabilizes finite LNAPA releases quickly is capillary retention. 00:35:19.000 --> 00:35:23.000 in the soil matrix. That is losses to residual saturation 00:35:23.000 --> 00:35:26.000 or LNAP will trapped in the soil pores. 00:35:26.000 --> 00:35:28.000 As El Napple migrates… 00:35:28.000 --> 00:35:32.000 laterally and vertically in the smear zone as that water table fluctuates. 00:35:32.000 --> 00:35:39.000 In summary, El Napple migration is self-limiting and a finite release. As the footprint expands. 00:35:39.000 --> 00:35:53.000 the gradient decreases, reducing that driving force. And as that footprint expands, a portion of that elm apple is retained in the soil pores as residual, reducing that potential mobility. 00:35:53.000 --> 00:36:03.000 And it is simply a finite release means a finite extent. 00:36:03.000 --> 00:36:09.000 In addition to that finite volume stabilizing LNAPLE bodies. 00:36:09.000 --> 00:36:14.000 Elena stability is also supported by active and natural loss mechanisms. 00:36:14.000 --> 00:36:19.000 While this quote that you see on the screen was intended for dissolved phase plumes. 00:36:19.000 --> 00:36:31.000 It also holds for an apple bodies. The loss mechanisms can be active recovery, enhanced biodegradation, natural biodegradation, or other mechanisms. 00:36:31.000 --> 00:36:37.000 Where these mechanisms result in sufficient losses in a given phase to balance out the flux of that phase. 00:36:37.000 --> 00:36:40.000 then stability can be achieved. 00:36:40.000 --> 00:36:47.000 The illustration here is depicting natural source zone depletion, or NSCD, that stabilizes the NAPA body. 00:36:47.000 --> 00:37:00.000 natural source zone depletion includes dissolution, volatilization, and biodegradation of the LNAP. 00:37:00.000 --> 00:37:08.000 Impacts to groundwater that occur as a result of finite L and apple releases have been investigated and studied over the past several decades. 00:37:08.000 --> 00:37:13.000 El Napple bodies were once thought to continue to migrate indefinitely. 00:37:13.000 --> 00:37:17.000 Similar to groundwater flow. However, field observations 00:37:17.000 --> 00:37:22.000 And an updated understanding of LNAPA behavior and saturated media. 00:37:22.000 --> 00:37:27.000 found that the finite elemental plumes become stable in relatively short periods of time. 00:37:27.000 --> 00:37:30.000 For several reasons, as we just covered in the previous slides. 00:37:30.000 --> 00:37:35.000 Early in the release, LNAPLE gradients and high saturations 00:37:35.000 --> 00:37:38.000 can dominate that movement and distribution. 00:37:38.000 --> 00:37:45.000 that movement and distribution can result in elen apple spraying that's faster than groundwater flow. 00:37:45.000 --> 00:37:50.000 due to these large gradients, large heads at the time of the release. They can also cause 00:37:50.000 --> 00:37:56.000 NAPA migration upgrading and cross gradient, this radial spreading. 00:37:56.000 --> 00:38:09.000 And these initial conditions will change over time as those L and Apple gradients dissipate and those LNAPLE saturations in the pore space reduce due to that spreading and losses to residual saturation. 00:38:09.000 --> 00:38:15.000 And as we mentioned, these plumes essentially stabilize in a relatively short period of time. 00:38:15.000 --> 00:38:21.000 what we've found is typically in less than five years. 00:38:21.000 --> 00:38:27.000 So the emerging method for evaluating LNAP stability is using multiple lines of evidence. 00:38:27.000 --> 00:38:33.000 This slide references lines of evidence provided in the upcoming ASTM. 00:38:33.000 --> 00:38:36.000 guide moving petroleum sites to closure. 00:38:36.000 --> 00:38:40.000 This is scheduled to be released next year. 00:38:40.000 --> 00:38:47.000 The intent here is just to provide an overview of some field-based lines of evidence used to assess El Napple stability. 00:38:47.000 --> 00:38:52.000 Now, the number of lines of evidence used at your site to demonstrate stability 00:38:52.000 --> 00:38:57.000 It depends on your CSM and the receptors 00:38:57.000 --> 00:39:03.000 and the conditions of your site. But the ASTM guide recommends that maybe as 00:39:03.000 --> 00:39:06.000 as little as one line of evidence is needed. 00:39:06.000 --> 00:39:15.000 If the release has been abated more than five years ago, if the release was abated less than five years ago or it's unknown. 00:39:15.000 --> 00:39:17.000 unknown, maybe two lines of evidence 00:39:17.000 --> 00:39:26.000 But it's important to know that the number of lines of evidence should be dependent on the complexity of the site and the proximity to your receptors. 00:39:26.000 --> 00:39:34.000 And of course, you know, in all cases, a CSM with sufficient data to demonstrate temporal and spatial variability is necessary to demonstrate 00:39:34.000 --> 00:39:42.000 your LNAPA is not migrating. 00:39:42.000 --> 00:39:44.000 We're going to take a quick… 00:39:44.000 --> 00:39:52.000 A quick break to do a little Q&A, a little live Q&A session. So I'll let Nicole moderate that for a few minutes. 00:39:52.000 --> 00:40:05.000 Thanks, Steve. We are working through the Q&A pod. So thank you for everybody that's using it as the questions come up to you. We are also responding to them, so you should be able to see the question and answers if you open 00:40:05.000 --> 00:40:11.000 And then I want to remind everybody that the next class 00:40:11.000 --> 00:40:17.000 this exact same session will be hosted January 30th and registration opens tomorrow. 00:40:17.000 --> 00:40:22.000 Same website that you logged into today will have the registration open. 00:40:22.000 --> 00:40:38.000 We're going to do two Q&A questions right now, and then Steve, we'll have you keep going. But Diana, when you are requesting TPH sampling at sites, do you need to request contractors break out additional sampling for LNAP? 00:40:38.000 --> 00:40:40.000 Thanks, Nicole. 00:40:40.000 --> 00:40:44.000 Ideally, I'm going to say yes. And the reason I'm saying this is because 00:40:44.000 --> 00:40:51.000 TP, typically your TPH analyses are gas chromatograph analyses and 00:40:51.000 --> 00:40:56.000 If you send a lab an L apple sample and ask them to analyze it by a GC method. 00:40:56.000 --> 00:40:59.000 it's going to get extremely diluted. 00:40:59.000 --> 00:41:05.000 And your results are probably not going to be very reliable because your lab's not going to want to blow out their analytical column. 00:41:05.000 --> 00:41:13.000 So yeah, generally you would want to sample those for, use different sampling for those. 00:41:13.000 --> 00:41:20.000 Great. Thank you. Matt, I know that you responded, but maybe you can um 00:41:20.000 --> 00:41:29.000 add on a little bit. Our hydrocarbon vapors in Vadosone sourced primarily from dissolved phase in groundwater or from elm apple? 00:41:29.000 --> 00:41:33.000 Yeah, thanks for the question, Nicole, and whoever raised it. 00:41:33.000 --> 00:41:44.000 they are going to be associated with an El Napple source. It's very rare. In fact, we asked this question once amongst the 00:41:44.000 --> 00:41:51.000 all of the folks who were involved in putting together the PVI technical reg 00:41:51.000 --> 00:41:54.000 whether or not they had ever seen 00:41:54.000 --> 00:41:56.000 a case where… 00:41:56.000 --> 00:42:03.000 they had petroleum vapor intrusion associated with a purely dissolved phase groundwater source and nobody 00:42:03.000 --> 00:42:08.000 could come up with one. So it is definitely a rare case 00:42:08.000 --> 00:42:20.000 But must be mindful that it's very easy to think that you have a dissolved phase source when actually residual LNAPPO might be present. It's just not showing up. 00:42:20.000 --> 00:42:27.000 in a groundwater monitoring well, and we'll talk a little bit more about that going forward. So good question. Thank you. 00:42:27.000 --> 00:42:37.000 That's great. And I want to compliment the attendees. We have a lot of really interesting questions coming in. We're doing our best to continue to answer them as we go forward. So keep 00:42:37.000 --> 00:42:44.000 populating the Q&A as we go, but I'm going to let Steve continue into the next key message. 00:42:44.000 --> 00:42:47.000 All right, thank you. And I see there's a couple of NAFL questions. 00:42:47.000 --> 00:42:49.000 Mark can either answer those 00:42:49.000 --> 00:42:56.000 or Matt can answer those on the chat or I can do them when I'm complete some of these uh 00:42:56.000 --> 00:42:59.000 my sections. 00:42:59.000 --> 00:43:03.000 But yeah, we're going to move on to move on to move on to move on. 00:43:03.000 --> 00:43:06.000 Key message number two. 00:43:06.000 --> 00:43:09.000 Which is elm apple thickness 00:43:09.000 --> 00:43:12.000 has often been used to evaluate Elmapple sites 00:43:12.000 --> 00:43:15.000 and make remedial decisions. 00:43:15.000 --> 00:43:19.000 But what are these gauge and apple thickness really telling us? 00:43:19.000 --> 00:43:26.000 And it's really not much other than NAFL is present in the formation. 00:43:26.000 --> 00:43:29.000 So LNAP will take this in a well. 00:43:29.000 --> 00:43:40.000 has different volumes in the formation depending on the soil type of the formation and different volumes in the formation result in different thicknesses in the well, depending on the soil type. 00:43:40.000 --> 00:43:45.000 The graphic in the middle represents a monitoring well with three feet of an apple. 00:43:45.000 --> 00:43:57.000 And the chart on the left presents different napple saturation profiles using the vertical equilibrium model for different soil types. And the El Napa specific volume associated with that soil type. 00:43:57.000 --> 00:44:01.000 The specific volume is the volume of elmapple 00:44:01.000 --> 00:44:06.000 per square foot of the aerial footprint of the Elen Apple body. 00:44:06.000 --> 00:44:10.000 in the early days, and some might still have this misperception 00:44:10.000 --> 00:44:15.000 Elenapel is thought to float on the water table and occupy 100% of the pore space. 00:44:15.000 --> 00:44:18.000 This is represented by that pink zone of the chart. 00:44:18.000 --> 00:44:22.000 The volume of gasoline via the pancake model was simply 00:44:22.000 --> 00:44:26.000 calculated by multiplying the thickness in the well 00:44:26.000 --> 00:44:29.000 by the porosity of the formation. In this case. 00:44:29.000 --> 00:44:32.000 seven and a half gallons per square foot. 00:44:32.000 --> 00:44:40.000 Research has shown that the elm apple shares the pore space with water and the distribution of NAPA water and air 00:44:40.000 --> 00:44:42.000 Depends on the soil and elen apple types. 00:44:42.000 --> 00:44:46.000 including capillary properties, interfacial tension, and density. 00:44:46.000 --> 00:44:49.000 The vertical equilibrium model, or VEQ, 00:44:49.000 --> 00:44:54.000 derived elm apple saturation profile looks like a shark fin. See the black 00:44:54.000 --> 00:44:58.000 Diane pink and red lines on the chart. 00:44:58.000 --> 00:45:00.000 And it's often referred to as a shark fin. 00:45:00.000 --> 00:45:06.000 The coarser the grain size, the higher the elm apple saturation for a given thickness. 00:45:06.000 --> 00:45:10.000 And the higher the specific volume for the same measured nappble thickness in the well. 00:45:10.000 --> 00:45:19.000 The pancake model over predicts the volume and the overprediction gets more and more significant as that grain size becomes smaller. 00:45:19.000 --> 00:45:25.000 LNAP will recovering at two wells with three feet of LNAPLE, one in gravel and one in silt. 00:45:25.000 --> 00:45:28.000 will have very different recovery rates. 00:45:28.000 --> 00:45:41.000 And this is a primary reason why El Napo transmissivity has become a key metric in El Napo remedial decision making. 00:45:41.000 --> 00:45:50.000 So I'm going to show you a quick movie about a diesel El Nava body in a gravelly sand aqua that is characterized by seasonal water table fluctuations. 00:45:50.000 --> 00:45:55.000 But quickly, the blue gauge on the right side of each picture provides the average water level. 00:45:55.000 --> 00:46:05.000 And the color contours represent the napple thickness in the wells. And that's what's plotted in the middle is the napple thickness, this body right here is the napple thickness over time. 00:46:05.000 --> 00:46:08.000 and each date. 00:46:08.000 --> 00:46:15.000 is plotted. So the extent engaged and apple thickness were measured in over 50 wells across the site for five years. 00:46:15.000 --> 00:46:20.000 The gauge and apple thickness in well measurements range from zero to four feet 00:46:20.000 --> 00:46:33.000 The groundwater level fluctuates approximately eight feet seasonally and the image illustrates the influence of water table fluctuations in trapping elm apple as the water rises into the Napple saturation profile. 00:46:33.000 --> 00:46:37.000 and the subsequent drainage of Napa during periods of low water level. 00:46:37.000 --> 00:46:45.000 During this time period, there's an operating LNAPA recovery system which resulted in the continued loss of El Napple mass from the aquifer. 00:46:45.000 --> 00:46:50.000 So if you're just looking at napple thicknesses and wells and trying to figure out what's happening. 00:46:50.000 --> 00:46:55.000 you might think there are new releases. You might think there are migration. 00:46:55.000 --> 00:46:58.000 Just by looking at where this napple appears and disappears at the site. 00:46:58.000 --> 00:47:00.000 So it's really important to think about 00:47:00.000 --> 00:47:02.000 what's happening at the water table. 00:47:02.000 --> 00:47:09.000 And to make these napple thicknesses change over time. 00:47:09.000 --> 00:47:13.000 So this next slide is going to give you a little more insight into what's happening. 00:47:13.000 --> 00:47:23.000 And hydrographs are an important piece of, you should always use a hydrograph when looking at an apple thicknesses over time, particularly. 00:47:23.000 --> 00:47:24.000 And that's what you're seeing on the bottom. 00:47:24.000 --> 00:47:31.000 The blue line is groundwater elevation. That red line is your NAPA thickness. 00:47:31.000 --> 00:47:39.000 And above that is kind of a vertical profile showing that water and napple saturation profile. Blue is water 00:47:39.000 --> 00:47:44.000 red is your natural saturation. And you can see that red looks like a shark fin. 00:47:44.000 --> 00:47:47.000 zeros percent saturations on the right 00:47:47.000 --> 00:47:50.000 And 100% saturation is on the left. 00:47:50.000 --> 00:47:53.000 at a panel a represents the panel represents 00:47:53.000 --> 00:47:57.000 say a new release, Nappa accumulates at the water table 00:47:57.000 --> 00:48:02.000 And when you look down below it, you have a measurable thickness in the well. 00:48:02.000 --> 00:48:05.000 In panel B, the water table falls 00:48:05.000 --> 00:48:10.000 And Tom mentioned it. You get this snail trail of Napple that napple 00:48:10.000 --> 00:48:15.000 falls with the water table and leaves some residual napple in the formation. 00:48:15.000 --> 00:48:19.000 You can see that red line along the VATO zone. 00:48:19.000 --> 00:48:24.000 And then in panel C, the water table begins to rise. 00:48:24.000 --> 00:48:26.000 And a lot of Napa was trapped 00:48:26.000 --> 00:48:30.000 is occluded in the pore spaces. And the key here is 00:48:30.000 --> 00:48:33.000 in a two-phase system under Napa and water 00:48:33.000 --> 00:48:40.000 The residual saturation for NAPA is higher. So more napa is trapped in the water and NAPA system than in air 00:48:40.000 --> 00:48:48.000 water and apple system. So as that water table rises, a lot of Napolis trapped in the porch space and you can see there's less 00:48:48.000 --> 00:48:53.000 NAFL in that shark fin portion at the water table. And there's less napple in the well. 00:48:53.000 --> 00:48:57.000 looking at that hydrograph. If that water table rises enough 00:48:57.000 --> 00:49:02.000 all the NAPA will be trapped as residual and you might not see Nappa in the well. 00:49:02.000 --> 00:49:08.000 If you think about that movie you just saw, there are time periods where there's no Napple appearing in the well. 00:49:08.000 --> 00:49:10.000 And then if the water table falls. 00:49:10.000 --> 00:49:15.000 Again, back to conditions that we saw in panel B. 00:49:15.000 --> 00:49:21.000 Napa will again accumulate in that well as we go back to that lower three phase residual saturation 00:49:21.000 --> 00:49:25.000 an apple can drain from those pore spaces that were previously occluded. 00:49:25.000 --> 00:49:28.000 So this happens all the time. 00:49:28.000 --> 00:49:35.000 a ton of calls, particularly during drought conditions where people call me and said, I have napoon wells that I haven't seen in 10 years. 00:49:35.000 --> 00:49:40.000 So this is a common condition. So again, it's very important to look at 00:49:40.000 --> 00:49:48.000 water tables when you're evaluating napple thicknesses and changes in those conditions. 00:49:48.000 --> 00:49:51.000 Oops. 00:49:51.000 --> 00:49:56.000 And again, thickness always seems like a good indicator. Easy to measure, easy to look at. 00:49:56.000 --> 00:50:02.000 But it's not. We've been discussing unconfined El Napple, which you see on the top section of this chart. 00:50:02.000 --> 00:50:06.000 We're El Napple in the well is adjacent to the bulk of the Napple. 00:50:06.000 --> 00:50:09.000 in the formation, typically at or near the water table. 00:50:09.000 --> 00:50:13.000 Water table fluctuations will have this inverse relationship. 00:50:13.000 --> 00:50:19.000 As the water table falls, the L and Apple thickness will increase. But what happens? 00:50:19.000 --> 00:50:24.000 When El Nappel is sitting on a low permeable layer. Look at the middle image on the lower level. 00:50:24.000 --> 00:50:27.000 This is called the perch L-napple condition. 00:50:27.000 --> 00:50:32.000 In this instance, the elen apple has enough head to migrate downward through the veto zone. 00:50:32.000 --> 00:50:42.000 But it can't because it's blocked by the soil poor fine grain soil with high engine pressure. 00:50:42.000 --> 00:50:44.000 If a well is advanced through this perching layer. 00:50:44.000 --> 00:50:48.000 that napple that's trapped, that's resting on that perching leg 00:50:48.000 --> 00:50:52.000 who enter that well and accumulate in that well, who depress the water 00:50:52.000 --> 00:50:58.000 that's at the water table and we'll fill that well up until it equilibrates with that napple at that perching layer. 00:50:58.000 --> 00:51:00.000 You'll get this exaggerated sickness. 00:51:00.000 --> 00:51:04.000 And as that water table falls. 00:51:04.000 --> 00:51:05.000 that an apple thickness will actually increase. 00:51:05.000 --> 00:51:09.000 So you get this exaggerated in well thickness. 00:51:09.000 --> 00:51:13.000 And if you look to the left, you have a confining condition. This is kind of the inverse. 00:51:13.000 --> 00:51:15.000 Napa was able to get 00:51:15.000 --> 00:51:26.000 below the water table, this might have happened during historical groundwater pumping, historical droughts. The Naples deep in the formation. It's trapped below a confining layer. 00:51:26.000 --> 00:51:30.000 And when the water table rises, that an apple enters 00:51:30.000 --> 00:51:34.000 can enter a well and fill that well up until that 00:51:34.000 --> 00:51:36.000 the hydrostatic pressure equivalent rates. 00:51:36.000 --> 00:51:40.000 And when the water table rises, napple thickness increases. 00:51:40.000 --> 00:51:48.000 And we see wells with 5, 10, 20, 40 feet of napple, all because of where that napple just exists below the water table. 00:51:48.000 --> 00:51:51.000 So you get these large exaggerations. 00:51:51.000 --> 00:51:52.000 And finally. 00:51:52.000 --> 00:51:56.000 certain fractured or preferential pathways you can 00:51:56.000 --> 00:52:01.000 without confined or perched behaviors depending on where the fracture network is. 00:52:01.000 --> 00:52:06.000 Or where the water chain was. So you get these additional complexities that really 00:52:06.000 --> 00:52:13.000 give you some challenges on what it means. So remember, LNAP and a monitoring well means LNAP was present in the formation 00:52:13.000 --> 00:52:20.000 And El Napa is mobile. It does not mean it's recoverable or migrating. Additional work is necessary to understand 00:52:20.000 --> 00:52:28.000 stability if it's migrating or if it's recoverable. 00:52:28.000 --> 00:52:34.000 And then we've been touching on it, and I think there was a question about residual NAFL. 00:52:34.000 --> 00:52:39.000 But this is one of the key points is LMAPPL can be hiding in plain sight. 00:52:39.000 --> 00:52:44.000 And this is one of these tricks that we have some tips for you to look for when you're 00:52:44.000 --> 00:52:51.000 trying to evaluate your site and looking for this residual napple. 00:52:51.000 --> 00:52:58.000 And as we kind of mentioned, I think there's some questions about it. Matt answered it. Why is it so critical? 00:52:58.000 --> 00:53:01.000 As we mentioned earlier, the magnitude of that mass in the Napple 00:53:01.000 --> 00:53:05.000 source drives the vapor and dissolves these plumes. 00:53:05.000 --> 00:53:11.000 understanding that an apple source is important when targeting remediation and identifying potential concerns. 00:53:11.000 --> 00:53:19.000 particularly important for site screening for PVI because that hydrocarbon vapors will tend to migrate farther above an L and Apple source. 00:53:19.000 --> 00:53:28.000 that it is all phase source. The magnitude of the vapor concentrations derived from NAPL is much greater than a dissolph phase plume. 00:53:28.000 --> 00:53:35.000 And because of that, that residual L-navel sources are often mistaken for dissolving sources. 00:53:35.000 --> 00:53:37.000 Even though they're present. 00:53:37.000 --> 00:53:40.000 And they represent a PVI risk as 00:53:40.000 --> 00:53:49.000 more similar to one where NAPA is mobile, right? So that mobile, you see those two graphics on the left, the mobile or migrating Apple or NAPPL is in a well. 00:53:49.000 --> 00:53:53.000 acts the same as a residual NAPPL source. 00:53:53.000 --> 00:53:55.000 Even though NAPA is not present. 00:53:55.000 --> 00:53:57.000 And the trick is 00:53:57.000 --> 00:54:06.000 wells with known apple looked just like a dissolved face. Well, so you have to, so it's critical to differentiate the two 00:54:06.000 --> 00:54:12.000 because of the magnitude of those sources, right? We'll have high dissolve phase plumes, we'll have strong vapor 00:54:12.000 --> 00:54:15.000 sources. 00:54:15.000 --> 00:54:17.000 So the nice thing is 00:54:17.000 --> 00:54:22.000 IGRC published some general indicators in the PVI guidance. 00:54:22.000 --> 00:54:28.000 These criteria here were based largely on assuming the Naples gasoline. 00:54:28.000 --> 00:54:34.000 Therefore, you should be applied with caution if assessing other fuel types. 00:54:34.000 --> 00:54:40.000 The NAPA indicators presented here are defined based on groundwater and soil concentration data. 00:54:40.000 --> 00:54:44.000 As well as the relative proximity to where the petroleum release initially occurred. 00:54:44.000 --> 00:54:50.000 The values listed in this table are not intended to be used as absolutes or even in isolation. 00:54:50.000 --> 00:54:54.000 Rather, as general rule of thumb and in multiple lines of evidence fashion. 00:54:54.000 --> 00:54:58.000 So these are just guidance. If you start seeing 00:54:58.000 --> 00:55:08.000 Some concentrations or these types of conditions, start thinking you might have residual napple in that vicinity. 00:55:08.000 --> 00:55:11.000 And then additionally, while not printed in the PBI guidance. 00:55:11.000 --> 00:55:13.000 If you have soil gas data. 00:55:13.000 --> 00:55:18.000 These type of concentrations could be indicative of an apple source. 00:55:18.000 --> 00:55:22.000 When we start talking about natural source zone depletion more, we start looking at 00:55:22.000 --> 00:55:25.000 Soil gas data as well as in 00:55:25.000 --> 00:55:28.000 TVI. But when you start seeing low oxygen 00:55:28.000 --> 00:55:31.000 elevated carbon dioxide and methane 00:55:31.000 --> 00:55:36.000 Those are strong indicators that there's biodegradation of an apple source 00:55:36.000 --> 00:55:41.000 in the formation. So again, indication of residual NAFL 00:55:41.000 --> 00:55:52.000 Elevated benzene at those concentrations. And then these hexanes and aliphatics. Those level of concentrations are typically not seen in the dissolve phase. 00:55:52.000 --> 00:55:57.000 Mostly because those are not very soluble compounds. So you wouldn't see them 00:55:57.000 --> 00:56:00.000 at any distance from an Apple source. 00:56:00.000 --> 00:56:05.000 So again, this table, these data is not in the PVI guidance 00:56:05.000 --> 00:56:12.000 But they were used when developing some of these screening distance. So just some other tools to use for yourself. 00:56:12.000 --> 00:56:15.000 And then finally, here's some um 00:56:15.000 --> 00:56:21.000 a list of a number of links that we provided from the LMApple 3 00:56:21.000 --> 00:56:24.000 guidance document to help develop your site CSM. 00:56:24.000 --> 00:56:37.000 All these LCSM, LMAPL conceptual site model elements provide important information to understand and predict LNAPA behavior at your site and are valuable lines of evidence to support management strategy. 00:56:37.000 --> 00:56:39.000 decision. So highly recommend 00:56:39.000 --> 00:56:47.000 to dive in, explore these tools. So it could be very helpful and useful. 00:56:47.000 --> 00:56:52.000 And then we're going to dive into key message number four. 00:56:52.000 --> 00:56:59.000 that biodegradation helps elena bodies in groundwater plumes stabilize and shrink. 00:56:59.000 --> 00:57:04.000 And this tax has been recognized and well documented for dissolph hydrocarbon plumes. 00:57:04.000 --> 00:57:08.000 Monitored natural attenuation is an established remedy. 00:57:08.000 --> 00:57:20.000 But this has not been identified as a significant factor in LNAPAL plume evolution until relatively recently. 00:57:20.000 --> 00:57:23.000 So a stable novel body is like a glacier. 00:57:23.000 --> 00:57:26.000 Glaciers are constantly flowing downhill. 00:57:26.000 --> 00:57:29.000 But that leading edge is stable. 00:57:29.000 --> 00:57:32.000 And that's because of the evaporation and melting 00:57:32.000 --> 00:57:35.000 along that glacier as it's moving. 00:57:35.000 --> 00:57:37.000 And a stable novel body. 00:57:37.000 --> 00:57:40.000 We have mobile novel. We have a gradient. 00:57:40.000 --> 00:57:45.000 theoretically, there's some Apple that might be moving along that napple body. 00:57:45.000 --> 00:57:50.000 However, we have natural losses that are occurring that are counteracting that. 00:57:50.000 --> 00:57:54.000 that migration that inside an Apple body. 00:57:54.000 --> 00:57:57.000 In this case, we have volatilization. 00:57:57.000 --> 00:58:01.000 dissolution and primarily biodegradation. 00:58:01.000 --> 00:58:06.000 Collectively, these processes are known as natural source zone depletion. 00:58:06.000 --> 00:58:14.000 for NSDD. 00:58:14.000 --> 00:58:22.000 And while aerobic biodegradation is recognized as the most rapid in situ destruction mechanism for hydrocarbons. 00:58:22.000 --> 00:58:25.000 L-naval bodies are almost always found in 00:58:25.000 --> 00:58:29.000 And basically they create an anaerobic environment. 00:58:29.000 --> 00:58:36.000 El Napple was once thought to weather primarily through volatilization and dissolution, which were 00:58:36.000 --> 00:58:41.000 Then biodegradation biodegraded in the vapor and dissolve phase. 00:58:41.000 --> 00:58:47.000 This misperception was largely because of the limited solubility of petroleum hydrocarbons. 00:58:47.000 --> 00:58:50.000 maybe the slow anaerobic degradation rates 00:58:50.000 --> 00:58:55.000 and possibly the toxic environment inhibiting microbial growth within the NAPA body. 00:58:55.000 --> 00:59:14.000 However, recent, relatively recent studies have shown that anaerobic biodegradation processes are very active within the elm apple body and biodegradation is a significant loss mechanism. 00:59:14.000 --> 00:59:16.000 And if you recall that shark fin model 00:59:16.000 --> 00:59:19.000 Where El Napple shares the pore space with the water. 00:59:19.000 --> 00:59:23.000 Microbes live in that water adjacent to the elm apple. 00:59:23.000 --> 00:59:34.000 They do not require hydrocarbons to be soluble as the microbes utilize surfactants and intercellular diffusion to overcome those solubility limits. 00:59:34.000 --> 00:59:43.000 microbial activities have been found at all petroleum sites from the Arctic to the equator. So we see this. They are ubiquitous everywhere we've looked, we've seen it. 00:59:43.000 --> 00:59:45.000 they're very 00:59:45.000 --> 00:59:53.000 agile and adaptable community, right? 00:59:53.000 --> 00:59:56.000 So again, a little details on what NSCD is. 00:59:56.000 --> 01:00:01.000 And at most sites, the NAFL, the majority of LNAPO is at or below the water table. 01:00:01.000 --> 01:00:05.000 The Elena source is anaerobic, as you mentioned. 01:00:05.000 --> 01:00:10.000 And methanogenesis is the primary microbial process depleting the elm apple. 01:00:10.000 --> 01:00:13.000 methane and carbon dioxide are generated. 01:00:13.000 --> 01:00:16.000 that methane has low solubility. 01:00:16.000 --> 01:00:19.000 And it off gases into the beta sum. 01:00:19.000 --> 01:00:22.000 Where it is aerobically degraded. 01:00:22.000 --> 01:00:26.000 utilizing oxygen and generating carbon dioxide and heat. 01:00:26.000 --> 01:00:31.000 The utilization of oxygen or the production of carbon dioxide and heat in the beta zone 01:00:31.000 --> 01:00:35.000 are typically what we use to quantify NSCD. 01:00:35.000 --> 01:00:39.000 that El Nappel biodegradation. 01:00:39.000 --> 01:00:42.000 As I said, mostly occurs in the saturated zone 01:00:42.000 --> 01:00:47.000 But that secondary reaction, the ones we actually can measure 01:00:47.000 --> 01:00:49.000 occur in the Vedo zone. 01:00:49.000 --> 01:00:52.000 And 99% of the NSED processes 01:00:52.000 --> 01:00:56.000 the degradation of the apple are typically accounted for. 01:00:56.000 --> 01:01:03.000 in these Vedo zone reactions that we can measure. Therefore, most of our quantification 01:01:03.000 --> 01:01:09.000 methods focus on these datosome reactions. That's why if people have heard about, we do CO2 flux. 01:01:09.000 --> 01:01:16.000 We do the gradient method looking at oxygen, and we do temperature evaluations, temperature profiling. 01:01:16.000 --> 01:01:24.000 And also there's some elm apple composition work being done out there. But we look at these beta zone reactions. We can capture all 01:01:24.000 --> 01:01:27.000 or 99% of that. 01:01:27.000 --> 01:01:38.000 NAPL depletion rate looking at these beta zone reactions. 01:01:38.000 --> 01:01:43.000 And this slide shows a comparison of NSCG rates and energy. 01:01:43.000 --> 01:01:45.000 engineered recovery rates 01:01:45.000 --> 01:01:49.000 And they're converted to NSCD units to kind of make this comparison. 01:01:49.000 --> 01:01:51.000 These units are in 01:01:51.000 --> 01:01:54.000 We often do it in gallons per acre per year. 01:01:54.000 --> 01:01:58.000 These are in liters per hectare per year. 01:01:58.000 --> 01:02:11.000 The box and whisker charts plots the actual remediation system recovery rates from 43 sites that demonstrate a range of several thousands to upwards of 30,000 01:02:11.000 --> 01:02:22.000 liters per hectare per year for active recovery. And then these other studies summarize NSED rates from 40 sites, and they show a similar range. 01:02:22.000 --> 01:02:27.000 That gray box is the middle 50th percentile. 01:02:27.000 --> 01:02:32.000 Basically, the box of the box and whisker chart. 01:02:32.000 --> 01:02:37.000 So this represents a similar range to the active remediation. 01:02:37.000 --> 01:02:41.000 And the 90th, basically, and also that study showed that 01:02:41.000 --> 01:02:50.000 90% of the NSED rates were greater than 1,600 liters per hectare per year or 170 01:02:50.000 --> 01:02:51.000 gallons per acre per year. 01:02:51.000 --> 01:02:53.000 excuse me, per year. 01:02:53.000 --> 01:02:58.000 And this chart just shows that NSCD can be as effective 01:02:58.000 --> 01:03:00.000 as engineered systems at many sites. 01:03:00.000 --> 01:03:09.000 Especially sites with mature elm apple plumes that are stable, maybe the transmissivity is low, the Napa is no longer recoverable. 01:03:09.000 --> 01:03:14.000 And one reason why is NSCD processes are working across the full footprint. 01:03:14.000 --> 01:03:20.000 Every drop of an apple, maybe not every drop, but right across the full footprint, the residual, the mobile 01:03:20.000 --> 01:03:25.000 the full vertical interval. It has 100 targeting 01:03:25.000 --> 01:03:27.000 So that's the power of NSCD. 01:03:27.000 --> 01:03:33.000 It works across the full flow. 01:03:33.000 --> 01:03:38.000 So in summary on NSCD, it should be an integral part 01:03:38.000 --> 01:03:42.000 and component of your LNAPO conceptual site model. 01:03:42.000 --> 01:03:48.000 NSD data can provide insight to the LNAPA distribution. 01:03:48.000 --> 01:03:50.000 kind of mentioned it earlier on being 01:03:50.000 --> 01:03:54.000 helping identify where your residual L-navel is. 01:03:54.000 --> 01:03:57.000 It can be used to evaluate 01:03:57.000 --> 01:04:03.000 persistence of constituents. You can use NSED processes and changing your own alcohol composition. 01:04:03.000 --> 01:04:12.000 to understand maybe how a compound might persist over time. Understanding the site's risk profile might allow NSD alone 01:04:12.000 --> 01:04:16.000 to be an effective remedy by itself. 01:04:16.000 --> 01:04:18.000 And then quantifying the NSD rate 01:04:18.000 --> 01:04:24.000 is also valuable. As LNAPA behavior and recoverability changes over time. 01:04:24.000 --> 01:04:27.000 Both these NSCD processes are always at work. 01:04:27.000 --> 01:04:34.000 And so remediation practitioners need to take this into account as remedy baselines or transition points 01:04:34.000 --> 01:04:43.000 for recovery strategies and treatment trains. 01:04:43.000 --> 01:04:49.000 And I'd like to touch on polar metabolites. I think I saw some silca gel cleanup questions come through. 01:04:49.000 --> 01:04:52.000 um and uh 01:04:52.000 --> 01:04:58.000 The biodegradation of petroleum compounds occurs over a number of steps. Benzene doesn't 01:04:58.000 --> 01:05:03.000 go to carbon dioxide and water instantly. There's a number of processes that happen. 01:05:03.000 --> 01:05:08.000 And you get these intermediate products of biodegradation 01:05:08.000 --> 01:05:12.000 petroleum metabolites and they're also called polar metabolites 01:05:12.000 --> 01:05:15.000 And they have some unique chemical properties. 01:05:15.000 --> 01:05:20.000 To begin with, the polymer tabloids include oxygen, which make them polar. 01:05:20.000 --> 01:05:24.000 which causes these polar metabolites to preferentially 01:05:24.000 --> 01:05:29.000 partition into water, making them very soluble and mobile. 01:05:29.000 --> 01:05:36.000 The table on the bottom right illustrates differences in solubilities and boiling points of N-hexane 01:05:36.000 --> 01:05:41.000 versus its polar metabolites to hexanone and hexanonoic acid. 01:05:41.000 --> 01:05:50.000 As you can see, and hexane solubility limit is three orders of magnitude lower than its polar metabolites. 01:05:50.000 --> 01:05:53.000 The result of this is shown in the plume graphic. 01:05:53.000 --> 01:06:07.000 in the upper center of the page, where polar metabolites have migrated further in groundwater versus dissolved phase hydrocarbons like DTEx. So the blue plume is longer than that orange plume. 01:06:07.000 --> 01:06:10.000 And we've seen this a number of times. 01:06:10.000 --> 01:06:18.000 Is TPH concentrations start to exhibit an increasing trend at older plumes. 01:06:18.000 --> 01:06:22.000 And the plume appears to be expanding. 01:06:22.000 --> 01:06:24.000 But it's due to the biodegradation 01:06:24.000 --> 01:06:30.000 and increases in polar metabolites. So when you just do TPH analysis. 01:06:30.000 --> 01:06:36.000 Without a silica gel cleanup, you can get this increasing TPH trend. 01:06:36.000 --> 01:06:44.000 So another thing to point out is metabolites also have different toxicological properties relative to the parent hydrocarbons. 01:06:44.000 --> 01:06:59.000 And toxicity factors develop for polar metabolites tend to be lower than the toxicity factors assigned to the undegrated hydrocarbons. 01:06:59.000 --> 01:07:04.000 So how do you identify a polar metabolites? Kind of touched on it briefly. 01:07:04.000 --> 01:07:10.000 One easy way is analysis of TPH with and without silica gel cleanup. 01:07:10.000 --> 01:07:14.000 The silica gel removes the polar metabolites. 01:07:14.000 --> 01:07:17.000 from the groundwater. 01:07:17.000 --> 01:07:32.000 And you can see, so that purple line is pointing to an analysis that it's circled of a TPHD sample with and without cleanup. So the sample without soca gel cleanup, the result is in green. 01:07:32.000 --> 01:07:35.000 2,900 micrograms per liter 01:07:35.000 --> 01:07:38.000 When you do your silica gel cleanup, it was non-detect. 01:07:38.000 --> 01:07:41.000 So that sample was all that was 01:07:41.000 --> 01:07:44.000 polar metabolites, theoretically. 01:07:44.000 --> 01:07:50.000 You can also, if you didn't have a silk or gel cleanup, it was done, you say some older data was all 01:07:50.000 --> 01:07:56.000 Just traditional TGH without silica child cleanup. Maybe you can look at your chromatograms. 01:07:56.000 --> 01:07:58.000 you might see this metabolite hump 01:07:58.000 --> 01:08:01.000 the UCM. 01:08:01.000 --> 01:08:04.000 That's typical of a 01:08:04.000 --> 01:08:07.000 polar metabolites captured in the chromatogram. 01:08:07.000 --> 01:08:10.000 So another line of evidence that there's 01:08:10.000 --> 01:08:15.000 polar metabolites in your analysis. And finally. 01:08:15.000 --> 01:08:19.000 The third line of evidence is the nature extent of the TPH. 01:08:19.000 --> 01:08:23.000 You can see the red lines pointing back towards that 01:08:23.000 --> 01:08:26.000 that polar metabolite CSM. 01:08:26.000 --> 01:08:34.000 Essentially asking if the sample in question was collected down gradient of both the release area and the dissolve phase extent in groundwater. 01:08:34.000 --> 01:08:38.000 And the illustration is a hypothetical site map. 01:08:38.000 --> 01:08:44.000 showing the LNAP release in dark orange, the dissolve phase BTEX in the light orange. 01:08:44.000 --> 01:08:50.000 And further downgraded migration of these petroleum metabolites shown in 01:08:50.000 --> 01:08:58.000 the light blue. The polar metabolites should travel further because they are polar they're much more soluble they're much more mobile 01:08:58.000 --> 01:09:05.000 Then the dissolved hydrocarbon aromatics and aliphatics. So, you know, putting together that CSM, putting together 01:09:05.000 --> 01:09:09.000 you know more lines of evidence to demonstrate that 01:09:09.000 --> 01:09:20.000 you do have these polar metabolites. 01:09:20.000 --> 01:09:28.000 And I just want to end my key message with that aero biodegradation is a key process that limits 01:09:28.000 --> 01:09:32.000 petroleum vapor intrusion. As petroleum hydrocarbons 01:09:32.000 --> 01:09:38.000 biodegradation rates in the beta zone exceed upward migration. That limits that. 01:09:38.000 --> 01:09:43.000 that TVI. Aerial biodegradation results in the utilization of oxygen 01:09:43.000 --> 01:09:51.000 And the chart on the right shows a typical vertical profile soil concentrations and temperature above an elm apple source. 01:09:51.000 --> 01:10:07.000 the methane generated from an anaerobic biodegradation of elm apple and hydrocarbons that volatilize from the elm apple utilize that oxygen near the elm apple source area, and in most cases, the methane generated from anaerobic biodegradation 01:10:07.000 --> 01:10:09.000 will be completely occupied. 01:10:09.000 --> 01:10:15.000 oxidized to carbon dioxide at some distance above the hydrocarbon data source. 01:10:15.000 --> 01:10:21.000 The point where this occurs is turn the aerobic anaerobic horizon. 01:10:21.000 --> 01:10:26.000 And it roughly coincides with the location of the beta zone where there is a complete attenuation of methane 01:10:26.000 --> 01:10:28.000 this red line. 01:10:28.000 --> 01:10:32.000 oxygen concentrations begin to increase, the blue line. 01:10:32.000 --> 01:10:37.000 and carbon dioxide concentrations begin to decrease, the green line. 01:10:37.000 --> 01:10:49.000 The interface is also where a temperature anomaly, the yellow line, is typically observed as a result of the heat generated from the oxidation of methane and other hydrocarbons. 01:10:49.000 --> 01:11:04.000 Is it also important to point out that the figure shown here is generally a representation of the conditions found in the VEDA zone above an LNAP pollute source, and the conceptual site model provides a theory to support soil gas and temperature methods for natural source completion. 01:11:04.000 --> 01:11:16.000 just aerobic and anaerobic interface would be located much closer to the water table, the dissolved phase source where there would be little, if any methane generated, like in a dissolved phase source area. 01:11:16.000 --> 01:11:19.000 And with that, I think I turn it over. 01:11:19.000 --> 01:11:22.000 to man. 01:11:22.000 --> 01:11:25.000 Yeah, hi, guys. 01:11:25.000 --> 01:11:32.000 And this key message five gets back to one of the questions that was asked earlier about 01:11:32.000 --> 01:11:41.000 What is the primary source for petroleum vapors? And it's primarily associated again with El Napple. 01:11:41.000 --> 01:11:44.000 And so this message is around source type 01:11:44.000 --> 01:11:50.000 Source type matters. Also, before we get into 01:11:50.000 --> 01:11:53.000 LNAPA versus groundwater. 01:11:53.000 --> 01:11:56.000 Source type matters from the perspective that 01:11:56.000 --> 01:12:01.000 PVI sources are mainly 01:12:01.000 --> 01:12:09.000 gasolines and not your diesels or your middle distillates, bunker fuel, fuel oil 01:12:09.000 --> 01:12:17.000 those fuel types that have the hydrocarbons or the higher carbon atom numbers. 01:12:17.000 --> 01:12:23.000 president because those are typically not volatile hydrocarbons. 01:12:23.000 --> 01:12:29.000 So it's gasoline we want to focus on. That's going to be the key risk driver for petroleum vapor intrusion. 01:12:29.000 --> 01:12:32.000 now we know in that. 01:12:32.000 --> 01:12:41.000 It's we need to, again, be able to differentiate between an LNAPL source and a dissolved phase source. And it's because it manifests itself in how we screen sites. 01:12:41.000 --> 01:12:54.000 So there is more vertical separation needed between your hydrocarbon source and soil or groundwater and you're building 01:12:54.000 --> 01:13:05.000 for concentrations of key constituents of concern, maybe it's benzene to fall below some kind of risk-based screening level. 01:13:05.000 --> 01:13:08.000 of concern for vapor intrusion. 01:13:08.000 --> 01:13:14.000 And as just presented to you by Steve, it's going to be 01:13:14.000 --> 01:13:24.000 Where you're above this anaerobic aerobic interface or horizon in that zone where aro biodegradation is occurring. And that's where 01:13:24.000 --> 01:13:34.000 Hydrocarbons are degraded faster than they can migrate vertically upward by processes such as diffusion and advection. 01:13:34.000 --> 01:13:36.000 So that's what makes 01:13:36.000 --> 01:13:41.000 this screening distance concept very, or hydrocarbon 01:13:41.000 --> 01:13:45.000 petroleum vapor intrusion sites very conducive for screening 01:13:45.000 --> 01:13:48.000 Based on distance. 01:13:48.000 --> 01:13:59.000 And so what you find in the ITRC document are screening distances of 15 to 18 feet recommended 01:13:59.000 --> 01:14:07.000 15 feet if you have a petroleum UST site and 18 feet if you have a petroleum industrial site, meaning you've got a refinery 01:14:07.000 --> 01:14:12.000 manufacturing site, pipeline release site, a terminal maybe. 01:14:12.000 --> 01:14:26.000 Some site where you have a larger volume of LNAPA that got into the subsurface that may create more of an anaerobic environment. And then we see five feet for dissolved phase sources. 01:14:26.000 --> 01:14:33.000 And it's six feet if you look at EPA's petroleum hydrocarbon guides. 01:14:33.000 --> 01:14:47.000 So we could apply those same vertical screening distances laterally because biodegradation is just going to do its thing regardless of where the LNAP is positioned relative to the building, but in the ITRC guidance. 01:14:47.000 --> 01:14:53.000 how we screen sites laterally is based on a distance of 30 feet. 01:14:53.000 --> 01:14:57.000 Not 15 feet or five feet. 01:14:57.000 --> 01:15:10.000 And it's all because, and this is what we call the lateral inclusion zone. So any building located within that 30 foot distance between El Napple source and the Vedo zone or a groundwater source 01:15:10.000 --> 01:15:17.000 is going to get screened in for potential vapor intrusion. And it's based on the fact that 01:15:17.000 --> 01:15:22.000 we just have greater uncertainty in where that 01:15:22.000 --> 01:15:30.000 lateral edge of the L-napple or dissolved phase source is, and that's because we space wells typically on the order 01:15:30.000 --> 01:15:32.000 tens of feet or 01:15:32.000 --> 01:15:45.000 you know five meters or so and just have some some ambiguity there. So it was meant to provide a buffer distance, but certainly if you can definitively find the edge of your source 01:15:45.000 --> 01:15:59.000 Yeah, you could default to distances of 5 and 15 feet. Now, I will point out one unusual feature issue that would come up is you could have El Napo within, let's say, 15 feet. 01:15:59.000 --> 01:16:08.000 of a building in the Vedos zone, but you also has its dissolphase source that goes underneath that building. In that scenario. 01:16:08.000 --> 01:16:13.000 the LNAPL screening distance would have to be applied. It trumps 01:16:13.000 --> 01:16:19.000 Trump's vote. Okay. 01:16:19.000 --> 01:16:23.000 There are site conditions where there are 01:16:23.000 --> 01:16:27.000 we can't apply the screening distances. And those are what we call 01:16:27.000 --> 01:16:32.000 precluding factors. And when these precluding factors are present such as 01:16:32.000 --> 01:16:42.000 preferential pathways where we might have utility corridors present, conduits or fractured rock that connects the vapor source to the building. 01:16:42.000 --> 01:16:47.000 And that's the operative word in there, connects the vapor source or connect 01:16:47.000 --> 01:16:55.000 They may be present at the site, but if they don't connect the two, then it's not serving as a preferential pathway. But if those are present. 01:16:55.000 --> 01:16:58.000 We cannot apply the screening distances. 01:16:58.000 --> 01:17:03.000 We can't apply them as well if we've got certain fuel types present like 01:17:03.000 --> 01:17:14.000 fuels that might have been in the marketplace back in the pre-1990s days, which had leaded fuels or leaded lead in them. 01:17:14.000 --> 01:17:17.000 As well as lead scavengers or 01:17:17.000 --> 01:17:19.000 future fuels that might become more 01:17:19.000 --> 01:17:26.000 prominent in the market that contain greater than 10% ethanol by volume. 01:17:26.000 --> 01:17:37.000 And it's just because we just don't have a lot of information on those types of fuels to know whether or not these screening distances apply. Well, that was 01:17:37.000 --> 01:17:45.000 Back in the days when this ITRC tech reg was put together back in 2014, 2015 timeframe. 01:17:45.000 --> 01:17:54.000 Since then, there has been some literature reported and suggests that lead scavengers are not going to create on a 01:17:54.000 --> 01:18:04.000 Or I'll say that the screening distances that have been developed of 5 and 15 feet will apply for both lead scavengers and for 01:18:04.000 --> 01:18:10.000 ethanol fuels containing ethanol in greater quantities than 10%. 01:18:10.000 --> 01:18:22.000 Also, a precluding factor here is expanding advancing plumes. Obviously, as a plume migrates down gradient, there's more potential for a building to 01:18:22.000 --> 01:18:35.000 potentially have a petroleum vapor intrusion issue, so we can't screen those out based on distance. And lastly, we can't screen out sites where we have unusual soil types, either very, very dry that don't have the moisture content. 01:18:35.000 --> 01:18:40.000 to support biodegradation or have a high organic matter. 01:18:40.000 --> 01:18:45.000 content, not your typical clays, but maybe a peat where 01:18:45.000 --> 01:18:54.000 there's some natural respiration going on that's consuming oxygen that would otherwise be available for biodegradation of the hydrocarbons. 01:18:54.000 --> 01:19:03.000 And EPA, I'll also note here, does have additional precluding factor defined in their guidance of buildings that have large 01:19:03.000 --> 01:19:10.000 foundation footprints of greater than 66 feet on the side or around 20 meters on the side. 01:19:10.000 --> 01:19:13.000 Now, if you can't screen out based on distance. 01:19:13.000 --> 01:19:19.000 ITRC recommends a hierarchy of sampling that would start 01:19:19.000 --> 01:19:21.000 with soil gas. 01:19:21.000 --> 01:19:30.000 Then sub slab, then indoor air. So if there's any separation between the building and your source of hydrocarbons in the subsurface. 01:19:30.000 --> 01:19:40.000 really want to target soil gas. And a lot of those times you're going to find that the concentrations for these key chemical concerns are already below a risk-based screening level for vapor intrusion. 01:19:40.000 --> 01:19:45.000 But we want to try to stay away from the building and around the building because of the fact that 01:19:45.000 --> 01:19:47.000 Once we get inside the building. 01:19:47.000 --> 01:19:59.000 we're going to potentially encounter indoor air sources of the same constituents that are found in gasoline, like BTEX, benzene, toluene, ethyl benzene, and xylenes. 01:19:59.000 --> 01:20:06.000 But also they'll get below the foundation because buildings breathe both ways depending on 01:20:06.000 --> 01:20:11.000 wind and pressure effects that may cause 01:20:11.000 --> 01:20:16.000 that pressure differential with inside the building versus the subsurface to 01:20:16.000 --> 01:20:20.000 to flip around. 01:20:20.000 --> 01:20:25.000 Those would be scenarios though in scenario two here where if your building is close to that. 01:20:25.000 --> 01:20:32.000 source of contamination, you may not have another option. You may have to do sub slab and indoor air sampling. 01:20:32.000 --> 01:20:34.000 And then there's other scenarios where 01:20:34.000 --> 01:20:39.000 Maybe you don't even have a building present where you have to rely on modeling. 01:20:39.000 --> 01:20:42.000 That's also discussed in this PVI document. 01:20:42.000 --> 01:20:48.000 Now, as I was saying, you go inside a building and there's a good chance you're going to find these same 01:20:48.000 --> 01:20:56.000 petroleum hydrocarbon showing up in indoor air. In fact, they did some background studies to find that you're going to counter those 01:20:56.000 --> 01:20:58.000 In 90% or more. 01:20:58.000 --> 01:21:04.000 of cases where you're sampling in indoor air. And if we look over here on the right side. 01:21:04.000 --> 01:21:07.000 for constituents like benzene, we can find where these 01:21:07.000 --> 01:21:12.000 concentrations of benzene in background indoor air 01:21:12.000 --> 01:21:18.000 are above like an order of magnitude almost above a 10 to the minus six 01:21:18.000 --> 01:21:23.000 risk level. And it's again it's coming from indoor air sources such as carpets 01:21:23.000 --> 01:21:26.000 paints, wall coverings. 01:21:26.000 --> 01:21:33.000 couch fabrics, all of that acts as a source for these chemicals. So it gets very difficult then to 01:21:33.000 --> 01:21:39.000 tell when you go indoors, where's that source of hydrocarbon vapors? Is it indoors or is it 01:21:39.000 --> 01:21:42.000 below the building foundations. 01:21:42.000 --> 01:21:52.000 And lastly, I'll leave you with in this PVI tech reg, you'll find a lot of great information on how to 01:21:52.000 --> 01:21:57.000 do the sampling for groundwater, soil, soil gas. 01:21:57.000 --> 01:22:05.000 crawl space, indoor air leads you through that and some of the analyses depending on your site conditions. 01:22:05.000 --> 01:22:11.000 look to this PVI tech reg as a good reference on unsampling and analysis. 01:22:11.000 --> 01:22:16.000 And with that, I think we're going to open it up for some questions. 01:22:16.000 --> 01:22:21.000 Yeah, thanks, Matt. And once again, thank you to our 01:22:21.000 --> 01:22:23.000 For questions? 01:22:23.000 --> 01:22:32.000 We are running a little behind our scheduled time, so in order to ensure that we can make it through all of the content, I'm just going to ask the one question. 01:22:32.000 --> 01:22:35.000 that we had that would be of 01:22:35.000 --> 01:22:38.000 an interesting conversation and it just disappeared. 01:22:38.000 --> 01:22:46.000 chat, but it is and tom i think that you're starting with it. And then I think we might have some other folks that want to chime in but 01:22:46.000 --> 01:22:47.000 Yeah, just… 01:22:47.000 --> 01:22:52.000 What is the difference between Dean Apple and El Napple? And can you identify those both for this? 01:22:52.000 --> 01:22:53.000 the audience. 01:22:53.000 --> 01:23:04.000 Right. I covered, thanks, Nicole. I covered this in the beginning under the fundamentals, but LNAPLE is a light non-aqueous phase liquid. In other words, it'll float on water. It's less dense than water. 01:23:04.000 --> 01:23:06.000 A DN apple is denser 01:23:06.000 --> 01:23:10.000 and water so it's a dense non-aqueous phase liquid. 01:23:10.000 --> 01:23:14.000 The difference between the two islnapple, of course, will float on water 01:23:14.000 --> 01:23:20.000 the DNAPA will sink through groundwater and will not stop until it comes to some sort of a barrier 01:23:20.000 --> 01:23:23.000 usually a geologic barrier or an aquatard 01:23:23.000 --> 01:23:28.000 And then move similarly to petroleum in that regard. 01:23:28.000 --> 01:23:31.000 So basically, the difference is in the chemistry 01:23:31.000 --> 01:23:36.000 And a lot of the dean apples are chlorinated hydrocarbons 01:23:36.000 --> 01:23:39.000 like perchloroethylene or trichloroethylene 01:23:39.000 --> 01:23:45.000 And El Napa was going to be a petroleum hydrocarbon, which is a distillate from crude oil. 01:23:45.000 --> 01:23:47.000 without the chlorinated 01:23:47.000 --> 01:23:54.000 attachments. 01:23:54.000 --> 01:24:00.000 That's great. And we did have a written response as well in the Q&A so you can 01:24:00.000 --> 01:24:13.000 you a little bit more. And again, I apologize, but in the interest of time, I'm going to move us forward into the next key message and set up Diana to talk us through the information here. 01:24:13.000 --> 01:24:20.000 And then we'll hopefully have some additional time at the end of the class for the rest of the Q&A, but again. 01:24:20.000 --> 01:24:23.000 You should all be seeing the questions. 01:24:23.000 --> 01:24:28.000 Here in the Q&A as well as the responses. And we hope that those are helpful to you. 01:24:28.000 --> 01:24:30.000 Diana? 01:24:30.000 --> 01:24:37.000 Thank you, Nicole. So I want to start off by hitting on a message that Tom talked about. 01:24:37.000 --> 01:24:42.000 Way up front, which is that TPH is not necessarily total. 01:24:42.000 --> 01:24:47.000 Not necessarily all for petroleum and not necessarily all hydrocarbons. 01:24:47.000 --> 01:24:51.000 So what does that mean? Because it really sounds very contradictory when you listen to it. 01:24:51.000 --> 01:25:00.000 So TPH is really, it's a measurement that we use when we're looking at the potential risk from a site. But the key thing to remember with TPH 01:25:00.000 --> 01:25:07.000 is that the number that the lab reports is really and truly defined by the analytical method that you use to measure it. 01:25:07.000 --> 01:25:11.000 So anytime you get a TPH analytical result, just remember it's an approximation. 01:25:11.000 --> 01:25:15.000 It's an approximate concentration of the total hydrocarbons. 01:25:15.000 --> 01:25:18.000 But what it really is, is that it is 01:25:18.000 --> 01:25:24.000 These analytical methods, by and large, your TPH, especially your bulk TPH methods like your 8015s. 01:25:24.000 --> 01:25:33.000 are doing a global extraction. So it's an extraction and a reporting of all of the organic compounds that can be pulled from that sample. 01:25:33.000 --> 01:25:38.000 That's why we mean that it's not necessarily all hydrocarbons and it's not necessarily all petroleum. 01:25:38.000 --> 01:25:43.000 So what your intent here is to give you information on what you're dealing with. 01:25:43.000 --> 01:25:47.000 But remember, when you get a TPH result, there's some fuzziness in that number. 01:25:47.000 --> 01:25:49.000 So… 01:25:49.000 --> 01:25:59.000 When we say it's very much defined by the method, what I'm showing on this slide is a series of materials that are actually not petroleum at all. 01:25:59.000 --> 01:26:02.000 But they were analyzed by four different TPH methods. 01:26:02.000 --> 01:26:09.000 And what you can see is that there's a significant difference in the result based on the analytical method that was used. 01:26:09.000 --> 01:26:14.000 And so when you're dealing with TPH, it's not a super straightforward analysis. 01:26:14.000 --> 01:26:21.000 You really have to pay attention to what methods your agency specifically requires. 01:26:21.000 --> 01:26:23.000 Because that will dictate the result. 01:26:23.000 --> 01:26:32.000 And you also need to pay attention to exactly what questions you're trying to answer because that may also change the results that you get or the methods that you choose to use. 01:26:32.000 --> 01:26:41.000 So one of the things, again, that we hit on is that when you get a TPH result, it's not all necessarily petroleum hydrocarbons. 01:26:41.000 --> 01:26:49.000 One of the ways that we use to clean that up is something called a silica gel cleanup, which basically means that your sample is run through a silica gel column. 01:26:49.000 --> 01:26:53.000 And non-hydrocarbons are removed from the sample. 01:26:53.000 --> 01:27:02.000 So the chromatograph on the left is showing you basically what we like to call a hump, or you might more technically hear it referred to as UCM, which is an unresolved complex mixture. 01:27:02.000 --> 01:27:08.000 And this basically means that the lab could not distinguish individual compounds. There was just too much going on. 01:27:08.000 --> 01:27:16.000 When you see this hump, that typically is indicating that you probably have a lot of nonpolars or metabolites, or sorry, a lot of polar metabolites in there. 01:27:16.000 --> 01:27:22.000 When you run the silica gel cleanup, though, you can see that once all of the non-hydrocarbons are removed. 01:27:22.000 --> 01:27:27.000 you actually had no true petroleum hydrocarbons in that sample. 01:27:27.000 --> 01:27:32.000 So your silica gel cleanup method really is going to help you distinguish between what really is hydrocarbon 01:27:32.000 --> 01:27:36.000 and what isn't. 01:27:36.000 --> 01:27:43.000 So with the different petroleum methods out there, and there's quite a bit, quite a few, how do you choose which method you want to use? 01:27:43.000 --> 01:27:52.000 Well, really, it comes down to, like I said, the questions you're trying to answer. Your bulk TPH methods like your EPA 8015, 01:27:52.000 --> 01:27:56.000 Texas 1005. Kansas also has bulk methods. 01:27:56.000 --> 01:28:02.000 These are really often used when you're kind of initially assessing your site and trying to determine your overall extent. 01:28:02.000 --> 01:28:06.000 The advantages are they're inexpensive, so you can run a lot of samples. 01:28:06.000 --> 01:28:12.000 But the disadvantage is that they're very likely to over predict what you have there in terms of actual hydrocarbons. 01:28:12.000 --> 01:28:16.000 And you have limited usability with these when it comes to risk assessment. 01:28:16.000 --> 01:28:22.000 Many states and many agencies will have a total TPH number criterion. 01:28:22.000 --> 01:28:28.000 But oftentimes it may not necessarily be a risk-based number, or if it is a risk-based number. 01:28:28.000 --> 01:28:31.000 It's typically based on the most 01:28:31.000 --> 01:28:38.000 conservative calculation of the different types of fractions that could be present in that sample. 01:28:38.000 --> 01:28:42.000 The next thing that you might want to consider is what we call a fractionation analysis. 01:28:42.000 --> 01:28:49.000 A fractionation analysis takes that total bulk TPH method and breaks it down into aliphatics versus aromatics. 01:28:49.000 --> 01:28:55.000 Like Tom mentioned up front and also breaks it down into different carbon chain length fractions. 01:28:55.000 --> 01:29:02.000 So this is where you're going to run like, for instance, your Massachusetts VPH and EPH methods, your Texas 1006 is a fractionation method. 01:29:02.000 --> 01:29:06.000 And the state of Washington has fractionation methods as well. 01:29:06.000 --> 01:29:11.000 These methods are useful because they actually give you more information on what you're dealing with. 01:29:11.000 --> 01:29:17.000 They can better define your actual risk characteristics because we can better target 01:29:17.000 --> 01:29:23.000 the risk values to the individual fractions. The downside is that they're more expensive. 01:29:23.000 --> 01:29:29.000 The other thing to note with fractionation methods is that silica gel is used as part of that fractionation process. 01:29:29.000 --> 01:29:33.000 So they do remove your non-hydrocarbons from the analysis. 01:29:33.000 --> 01:29:39.000 And then last, what we touched on earlier is your silica gel cleanup. This is useful to help you remove your non-hydrocarbons. 01:29:39.000 --> 01:29:45.000 It can help you distinguish whether or not you're dealing with metabolites or your original petroleum product. 01:29:45.000 --> 01:29:53.000 And they can help you with defining what your fate and transport properties are by kind of making some of those distinctions. 01:29:53.000 --> 01:30:02.000 So that was a real quick run through on some of the key things to think about when you're looking at analytical methods for TPH, but the basic thing to keep in mind 01:30:02.000 --> 01:30:08.000 is that your method is giving you information on your distribution of TPH, the size of the hydrocarbons. 01:30:08.000 --> 01:30:12.000 Particularly if you look at the chromatograms and you can see those breakdowns. 01:30:12.000 --> 01:30:17.000 But the key things to remember is that the result is going to vary by the analytical method you use to use it. 01:30:17.000 --> 01:30:27.000 It also could potentially vary from lab to lab because different labs will use that different internal standards to calibrate their instruments. 01:30:27.000 --> 01:30:31.000 If you suddenly switch labs in the middle of your investigation. 01:30:31.000 --> 01:30:35.000 Don't be surprised if your TPH results don't look the same anymore. 01:30:35.000 --> 01:30:42.000 And again, it could also include your non-hydrocarbons. So the thing to remember is your TPH analytical result 01:30:42.000 --> 01:30:51.000 It's not necessarily total. It's not necessarily all petroleum and it's not necessarily all hydrocarbons. 01:30:51.000 --> 01:30:58.000 So moving from your analysis, we want to talk about actually how you're going to use some of that data and how the composition of the fuel 01:30:58.000 --> 01:31:00.000 assesses the risk. 01:31:00.000 --> 01:31:02.000 of your petroleum. 01:31:02.000 --> 01:31:10.000 So looking at this one thing, the first thing that I have up here is an example of three different chromatograms. 01:31:10.000 --> 01:31:15.000 that all showed a TPH result of 15,000 milligrams per kilogram. 01:31:15.000 --> 01:31:21.000 But if you look at the individual chromatographs, you can see that the one on the far left, which is your gasoline. 01:31:21.000 --> 01:31:28.000 is far heavier populated on the lower end of the spectrum. Your lighter end compounds are here. 01:31:28.000 --> 01:31:31.000 As opposed to diesel fuel, which is much more populated in the middle. 01:31:31.000 --> 01:31:37.000 And as opposed to crude, which has got a pretty good distinction across the whole spectrum. 01:31:37.000 --> 01:31:39.000 What this really means 01:31:39.000 --> 01:31:48.000 is that depending upon what product you're dealing with, you will have a very different risk profile, even though your TPH number is exactly the same. 01:31:48.000 --> 01:31:54.000 This is why we tell you that when you're trying to use a bulk TPH method, it's going to have limited usability. 01:31:54.000 --> 01:31:57.000 from a risk assessment standard because 01:31:57.000 --> 01:32:02.000 the information behind that number really can dictate a whole lot in terms of potential exposure 01:32:02.000 --> 01:32:06.000 and potential toxicity. 01:32:06.000 --> 01:32:13.000 So I'm going to revisit a slide that Matt had up there earlier when he was talking about conceptual site standards, or sorry, conceptual site 01:32:13.000 --> 01:32:21.000 models. And the reason I want to revisit this is because this really touches on a key point when you're doing risk assessment with TPH. 01:32:21.000 --> 01:32:26.000 And that is coming back to the idea that TPH is a complex mixture, which means 01:32:26.000 --> 01:32:32.000 In different parts of your site, you're going to have different ratios of compounds present. For instance. 01:32:32.000 --> 01:32:34.000 When you get up near the source. 01:32:34.000 --> 01:32:36.000 you're going to be predominantly LNABL. 01:32:36.000 --> 01:32:49.000 As you get into the vapor phase, you're going to be you're going to have a lot of vapor, but you also will have some sorbed and some dissolved. And I'm sorry, I didn't mean vapor phase. I mean, when you get up into the soil column. 01:32:49.000 --> 01:32:51.000 As you move down gradient. 01:32:51.000 --> 01:32:56.000 you're going to have more hydrocarbons and you're going to have more metabolites most likely. 01:32:56.000 --> 01:32:58.000 So what does this mean from a risk standpoint? 01:32:58.000 --> 01:33:04.000 It means that you can't collect your data from one spot and assume that it's going to accurately represent your risk across the entire site. 01:33:04.000 --> 01:33:10.000 You really need to make sure that you're collecting data from the areas where you have potential exposures. 01:33:10.000 --> 01:33:17.000 And the other thing that you need to keep in mind is goes back to something Steve was talking about with the biodegradation. 01:33:17.000 --> 01:33:22.000 The ratios of compounds will change over time. 01:33:22.000 --> 01:33:28.000 So if you're looking at old data, it may not give you an accurate representation of what your current risks look like. 01:33:28.000 --> 01:33:33.000 So make sure that you're collecting your method to accurately evaluate the different pathways 01:33:33.000 --> 01:33:39.000 the different areas of your site and the different timeframes that you're dealing with. 01:33:39.000 --> 01:33:45.000 The next thing I want to touch at in terms of TPH complexities when it comes to risk assessment is looking at toxicity. 01:33:45.000 --> 01:33:47.000 So… 01:33:47.000 --> 01:33:58.000 Coming up with toxicity values for a complex mixture of compounds isn't necessarily straightforward. And there's a few different things that have happened over time and that are still being used today. 01:33:58.000 --> 01:34:04.000 One of them is what we call this individual compound approach, which is basically where you focus your entire risk assessment 01:34:04.000 --> 01:34:09.000 on target compounds, which would typically be your BTECs and your PAHs. 01:34:09.000 --> 01:34:16.000 And this allows you to really assess what your carcinogenic risks are because those are the compounds you're looking at there. 01:34:16.000 --> 01:34:21.000 And it allows you to assess your risk from some of the key chemicals 01:34:21.000 --> 01:34:27.000 But in some cases, particularly if you have a highly weathered situation. 01:34:27.000 --> 01:34:30.000 they may not actually accurately capture accurately 01:34:30.000 --> 01:34:37.000 the entire site risk because you're missing essentially you're missing the aliphatic phase on this one. 01:34:37.000 --> 01:34:41.000 Another option is to use what we call whole product toxicity values. 01:34:41.000 --> 01:34:47.000 And what this means is that there actually are toxicity values out there for things like mineral oil. 01:34:47.000 --> 01:34:49.000 And JP4, et cetera. 01:34:49.000 --> 01:34:57.000 So it seems like that would be great, but the downside is that those toxicity values are based on fresh product and are based on a particular fresh product. 01:34:57.000 --> 01:35:02.000 And so your chemical distribution may not be identical for different 01:35:02.000 --> 01:35:06.000 products. And once the product ages 01:35:06.000 --> 01:35:09.000 then it no longer looks the same as it did when it was whole. 01:35:09.000 --> 01:35:14.000 So you're trying to use a whole product toxicity value is going to be limited in utility 01:35:14.000 --> 01:35:18.000 to really when you have a very fresh spell and you know exactly what was spilled. 01:35:18.000 --> 01:35:24.000 The most common method and the method that we tend to rely on is what we call a fractionation and a surrogate method. 01:35:24.000 --> 01:35:29.000 It means that your lab has broken down your TPH result into individual fractions. 01:35:29.000 --> 01:35:35.000 So you've got your aliphatic fraction separated from your aerobic, and you've got it broken down into 01:35:35.000 --> 01:35:37.000 to distinct carbet chain lengths 01:35:37.000 --> 01:35:42.000 And then within each of these carbon chain lengths and aromatic versus aliphatic. 01:35:42.000 --> 01:35:50.000 a surrogate chemical has been assigned in order to try to accurately represent the toxicity of that particular fraction. 01:35:50.000 --> 01:35:55.000 This at the moment is really probably the most accurate way we have to assess risk from TPH. 01:35:55.000 --> 01:36:02.000 So that's what you'll commonly see used if you're going to be doing a risk assessment on a TPH site. 01:36:02.000 --> 01:36:04.000 One thing to note, though. 01:36:04.000 --> 01:36:09.000 Different agencies have different analytical methods like we touched on earlier. 01:36:09.000 --> 01:36:17.000 And similarly, different agencies will have different fractionation breakdowns that line up best with their method. 01:36:17.000 --> 01:36:27.000 So when you're doing risk assessment, you need to make sure that you're very clear on using an analytical method that is appropriate for the agency that has jurisdiction over your site. 01:36:27.000 --> 01:36:29.000 And it accurately reflects accurately reflects 01:36:29.000 --> 01:36:38.000 The toxicity values that are being used to calculate the screening levels for that particular agency. 01:36:38.000 --> 01:36:44.000 So having touched on some of those things, one of the things that we proposed when we put together the TPH risk document 01:36:44.000 --> 01:36:50.000 was a tiered approach. And we feel like TPH really lends itself well to this because 01:36:50.000 --> 01:36:54.000 Your tier one is essentially what we call your screening level risk assessment. 01:36:54.000 --> 01:37:02.000 And that is really where you may be looking at things like you may be early in your process. You may only have bulk TPH data. 01:37:02.000 --> 01:37:11.000 And so you can do a very generalized evaluation. Now, if you have both TPH data and it happens to fall below your state's bulk TPH screening lessons. 01:37:11.000 --> 01:37:13.000 Great, you may be done. 01:37:13.000 --> 01:37:22.000 But oftentimes that's not going to happen because your bulk TPH number encompasses a lot of different ranges of carbon chain length ranges. 01:37:22.000 --> 01:37:31.000 And your TPH rescreening level, particularly if it's risk-based, tends to be based on the most conservative of those ranges. 01:37:31.000 --> 01:37:47.000 So in those cases, that'll lead you to a tier two or tier three, which is more site specific. You'll probably be using fractionation data and you'll be able to get a much better understanding of what your actual site risks are based on what you have present at your site. 01:37:47.000 --> 01:37:55.000 So the last thing I want to sum up here is kind of what we're dealing with when we're trying to assess risk from TPH. And the first thing to keep in mind 01:37:55.000 --> 01:38:00.000 is it's not a single chemical. It's a complex mixture. So you have to take into account 01:38:00.000 --> 01:38:05.000 the behavior of that mixture over time and as it moves through the environment. 01:38:05.000 --> 01:38:11.000 And those fate and transport properties are going to affect how you're going to assess your risk 01:38:11.000 --> 01:38:15.000 Where you're going to want to collect data and what kind of data you're going to want to collect. 01:38:15.000 --> 01:38:23.000 Because there are many different types of TPH data that does lend itself to kind of a tiered approach like we talked about. 01:38:23.000 --> 01:38:30.000 But the real true key here is that you have to understand your analytical data. You really want to have a good understanding of your conceptual site model. 01:38:30.000 --> 01:38:36.000 And the regulatory framework, the agency that has jurisdiction over your site is absolutely critical. 01:38:36.000 --> 01:38:41.000 and accurately and appropriately assessing the risk from a site. 01:38:41.000 --> 01:38:50.000 So with that, I'm going to hand it over to Lloyd, who can talk about risk management. 01:38:50.000 --> 01:38:57.000 Okay, let's wrap this up by talking about risk management. 01:38:57.000 --> 01:39:02.000 So… 01:39:02.000 --> 01:39:05.000 Now let's talk about what are you going to do to address it? 01:39:05.000 --> 01:39:09.000 What are your risk management options? 01:39:09.000 --> 01:39:13.000 So what are you going to do about it? Now, once you have a good CSM, 01:39:13.000 --> 01:39:19.000 You can then decide what are your options to address any petroleum risk that you have. 01:39:19.000 --> 01:39:21.000 Now you can collect additional data 01:39:21.000 --> 01:39:25.000 to help you decide which risk management option do you want to pursue. 01:39:25.000 --> 01:39:30.000 Or you may decide that you want to choose a remedial action for El Napple 01:39:30.000 --> 01:39:33.000 Or does all face concerns. 01:39:33.000 --> 01:39:35.000 Now, if you have migrating nail an apple. 01:39:35.000 --> 01:39:39.000 An option may be an option 01:39:39.000 --> 01:39:44.000 maybe that you could decide on placing 01:39:44.000 --> 01:39:47.000 a barrier wall or an engineering control 01:39:47.000 --> 01:39:50.000 If you have a PVI concern, you can select 01:39:50.000 --> 01:39:54.000 An active or passive system to manage the risk. 01:39:54.000 --> 01:39:57.000 Or you could decide that placing institutional controls 01:39:57.000 --> 01:40:05.000 will be more appropriate. Now, the ITRC guidance document in the references are excellent documents to help you decide 01:40:05.000 --> 01:40:08.000 What risk management options that you may want to consider. 01:40:08.000 --> 01:40:19.000 Now, the ITRC guidance documents will take you through the process to select the best option. 01:40:19.000 --> 01:40:25.000 Okay, so first you need to clarify exactly what is your LNAPA concern. 01:40:25.000 --> 01:40:29.000 Is it a risk concern such as benzene in the groundwater? 01:40:29.000 --> 01:40:35.000 Then you have a composition goal because benzene exists in the petroleum. 01:40:35.000 --> 01:40:38.000 Now, if you're ill and ample concern is a migration. 01:40:38.000 --> 01:40:45.000 Then your goal could be to address El Napple saturation. 01:40:45.000 --> 01:40:48.000 The same will be if your concern is with the mobile 01:40:48.000 --> 01:40:51.000 Or residual LNAPA. 01:40:51.000 --> 01:40:53.000 The goal will be to address composition 01:40:53.000 --> 01:40:57.000 or L-Nample saturation. 01:40:57.000 --> 01:41:02.000 Now, in some cases, you may have an aesthetic concern 01:41:02.000 --> 01:41:04.000 Such as a hydrocarbon odor. 01:41:04.000 --> 01:41:08.000 Or El Napo stained soils. 01:41:08.000 --> 01:41:11.000 That would be handled on a site-specific basis 01:41:11.000 --> 01:41:16.000 As explained on the next slide. 01:41:16.000 --> 01:41:20.000 So let's talk about these remedial goals in more detail. 01:41:20.000 --> 01:41:23.000 Now, if you have a saturation goal 01:41:23.000 --> 01:41:27.000 An objective would be to reduce the El Napple mass. 01:41:27.000 --> 01:41:29.000 Or recover the El Napple. 01:41:29.000 --> 01:41:33.000 An example would be to stop El Naval migration 01:41:33.000 --> 01:41:39.000 By installing a barrier wall or reducing open apple saturation by recovering ill napple. 01:41:39.000 --> 01:41:42.000 Now, if you have a composition goal. 01:41:42.000 --> 01:41:45.000 The objective would be the Aleen apple phase change 01:41:45.000 --> 01:41:50.000 An example would be to reduce the benzene concentration in the elen apple 01:41:50.000 --> 01:41:54.000 or subsurface soils or groundwater. 01:41:54.000 --> 01:42:00.000 Now, if you have an aesthetic goal, you could eliminate the cause of the concern 01:42:00.000 --> 01:42:03.000 An example would be to remove Elena stained soils 01:42:03.000 --> 01:42:06.000 Even though it's not creating a risk. 01:42:06.000 --> 01:42:15.000 Or another example would be stopping the elk apple from seeping into soils along a river. 01:42:15.000 --> 01:42:19.000 Okay, so when you've identified your concerns 01:42:19.000 --> 01:42:22.000 And then selected your remedial goals 01:42:22.000 --> 01:42:30.000 Then you can go to the ITRC Hill Napple guidance document if you want to install a remedial technology. 01:42:30.000 --> 01:42:35.000 It will list several types of remedial technologies that we show here. 01:42:35.000 --> 01:42:39.000 in a process of how to select a technology. 01:42:39.000 --> 01:42:44.000 Now, the remedial technologies are grouped in three remedial groups. 01:42:44.000 --> 01:42:46.000 that align with your goal. 01:42:46.000 --> 01:42:49.000 Now, phase change technologies are on the top 01:42:49.000 --> 01:42:53.000 Mass recovery technologies are on the left. 01:42:53.000 --> 01:42:58.000 And mask control technologies are on the right. 01:42:58.000 --> 01:43:03.000 Now within the circles, you will see a list of different types of remedial technologies. 01:43:03.000 --> 01:43:08.000 Now, all of these are thoroughly explained in the ITRC LNAPA guidance 01:43:08.000 --> 01:43:13.000 document. So now you will know where to go to learn about technology 01:43:13.000 --> 01:43:17.000 And what that may be able to do, what it may be able to accomplish 01:43:17.000 --> 01:43:23.000 Now you can see some remedial technologies fit into more than one grouping. 01:43:23.000 --> 01:43:26.000 For example, in the center of all three circles. 01:43:26.000 --> 01:43:30.000 Multiphase extraction, or MPE, 01:43:30.000 --> 01:43:32.000 can address your goals of phase change 01:43:32.000 --> 01:43:36.000 mass recovery and mass control. 01:43:36.000 --> 01:43:38.000 That is why it is a technology 01:43:38.000 --> 01:43:42.000 that is frequently used. 01:43:42.000 --> 01:43:44.000 now each 01:43:44.000 --> 01:43:49.000 Remedial technology selected requires alignment with key stakeholders. 01:43:49.000 --> 01:43:52.000 On performance metrics and endpoints. 01:43:52.000 --> 01:43:56.000 Preferably before the remedy is installed. 01:43:56.000 --> 01:44:00.000 Now, understanding rates of natural attenuation are key 01:44:00.000 --> 01:44:08.000 to ensuring that the remedy is performing optimally and sustainably. You've heard about that in the last couple of hours. 01:44:08.000 --> 01:44:15.000 So in addition, it is important to understand what metrics will be used to assess your performance. 01:44:15.000 --> 01:44:20.000 Now, each remedial technology also requires alignment 01:44:20.000 --> 01:44:25.000 With key stakeholders on what criteria will be used to define when the remedy 01:44:25.000 --> 01:44:28.000 is no longer beneficial. 01:44:28.000 --> 01:44:32.000 It is time to either transition to another active remedy 01:44:32.000 --> 01:44:38.000 or NSCD or moderate natural attenuation or even a no further action. 01:44:38.000 --> 01:44:43.000 Now, transition thresholds and validation assessments can help here 01:44:43.000 --> 01:44:57.000 Now, new guidance coming from ASTM on advancing the corrective action sites to closure has compiled some examples of performance metrics and endpoints which are presented on the next couple of slides. 01:44:57.000 --> 01:45:01.000 Now, as you've been told, the ASTM document is currently in draft 01:45:01.000 --> 01:45:05.000 and is due out soon. So make sure and watch out for it. 01:45:05.000 --> 01:45:08.000 Now the endpoints need to be set up front. 01:45:08.000 --> 01:45:14.000 So you will know when the technology has met its endpoint. 01:45:14.000 --> 01:45:23.000 Now, once the endpoint has reached for the technology, the technology should be transitioned to another more appropriate technology 01:45:23.000 --> 01:45:29.000 Based upon the new and current hill napple or your chemical of concern conditions. 01:45:29.000 --> 01:45:34.000 At this point, you should address whether you have validated your cleanup goals 01:45:34.000 --> 01:45:40.000 And your concerns have been addressed. 01:45:40.000 --> 01:45:48.000 So let's talk about performance metrics. Now, you don't need to read all of these. I just want to show you some examples of some of these. There's a lot of them. 01:45:48.000 --> 01:45:53.000 So all of these and more are found in the ITRC LNAPA guidance document. 01:45:53.000 --> 01:45:56.000 And the ASTM document. 01:45:56.000 --> 01:46:01.000 So let's take a look at the upper system related metric on the left. 01:46:01.000 --> 01:46:03.000 If you've set a metric. 01:46:03.000 --> 01:46:09.000 that when the chemical of concern has been reduced to a certain level. 01:46:09.000 --> 01:46:11.000 In the influence of your remediation system. 01:46:11.000 --> 01:46:15.000 And no further reductions are occurring 01:46:15.000 --> 01:46:20.000 then that remediation system should be transitioned to another system 01:46:20.000 --> 01:46:25.000 Or decide if you have reached an endpoint for the site. 01:46:25.000 --> 01:46:28.000 On the subsurface side on the right. 01:46:28.000 --> 01:46:36.000 If you set a metric that when your remediation goal has reduced groundwater concentrations in the subsurface to a certain level. 01:46:36.000 --> 01:46:41.000 And your remedial system is no longer reducing the concentrations in the groundwater. 01:46:41.000 --> 01:46:45.000 The NAS system should be transitioned to another system 01:46:45.000 --> 01:46:50.000 Or decide if you've reached the endpoint for even using their system. 01:46:50.000 --> 01:46:58.000 So you can see there are multiple ways to look at performance metrics 01:46:58.000 --> 01:47:01.000 So take examples of some endpoints here. 01:47:01.000 --> 01:47:07.000 Now, the ACM guidance document helps define the endpoints. 01:47:07.000 --> 01:47:12.000 They're also broken out into what is a saturation concern 01:47:12.000 --> 01:47:16.000 and those that relate to a composition concern. 01:47:16.000 --> 01:47:23.000 Now, finally, you want to make sure and set realistic endpoints for your remediation technology. 01:47:23.000 --> 01:47:29.000 If you reach the endpoint for the technology that you've predetermined upfront 01:47:29.000 --> 01:47:34.000 Further ill naple recovery will not be effective with that technology. 01:47:34.000 --> 01:47:40.000 Now here are several endpoints found in the ITRC LNAPA guidance document. 01:47:40.000 --> 01:47:45.000 And also the ASTM document. So let's take a look at a few. 01:47:45.000 --> 01:47:49.000 The first one is to understand the amount of ale napple 01:47:49.000 --> 01:47:54.000 that can effectively be recovered from the subsurface. 01:47:54.000 --> 01:47:57.000 Now, as we talked about, not all the elton apple 01:47:57.000 --> 01:48:01.000 Especially residual ale napple can be removed 01:48:01.000 --> 01:48:03.000 Unless you dig it all out. 01:48:03.000 --> 01:48:09.000 Now, if a transmissivity is below the threshold of 0.1 to 0.8, 01:48:09.000 --> 01:48:14.000 Feed squared per day. And further, Elenample recovery is extremely limited 01:48:14.000 --> 01:48:16.000 Or not even possible. 01:48:16.000 --> 01:48:19.000 So you are wasting your money by continuing. 01:48:19.000 --> 01:48:23.000 Unless you transition to another system. 01:48:23.000 --> 01:48:27.000 Now, another endpoint is a decline curve analysis. 01:48:27.000 --> 01:48:30.000 If the LNAP removal from the active system 01:48:30.000 --> 01:48:32.000 He was approaching asymptotic. 01:48:32.000 --> 01:48:34.000 or recovery is limited. 01:48:34.000 --> 01:48:39.000 But your greenhouse gas emissions that are produced operate the system are substantial. 01:48:39.000 --> 01:48:42.000 You should transition to another remedial system. 01:48:42.000 --> 01:48:47.000 Or you could decide if you've met your goals for El Napa mass removal. 01:48:47.000 --> 01:48:57.000 Just refer back to the ITRC document and the ASTN document to make sure you've set realistic endpoints. 01:48:57.000 --> 01:48:59.000 Something that is specific. 01:48:59.000 --> 01:49:02.000 measurable, achievable. 01:49:02.000 --> 01:49:04.000 realistic and time bound. 01:49:04.000 --> 01:49:12.000 Now, these are called smart objectives. 01:49:12.000 --> 01:49:17.000 So let's go over a summary of what we've been talking about in the last couple of hours. 01:49:17.000 --> 01:49:21.000 The characterization of TPH in the LNAPL and PVI 01:49:21.000 --> 01:49:23.000 It's an integrated approach. 01:49:23.000 --> 01:49:27.000 that starts with your CSM. 01:49:27.000 --> 01:49:30.000 So key messages from the TPH. 01:49:30.000 --> 01:49:35.000 Like Diana talked about, TPH is defined by the analysis you do. 01:49:35.000 --> 01:49:38.000 An analysis characterizes the nature and extent 01:49:38.000 --> 01:49:42.000 And whether biodegradation is occurring. 01:49:42.000 --> 01:49:45.000 plus the presence of petroleum metabolites. 01:49:45.000 --> 01:49:49.000 Now the type of TPH analysis depends on the site investigation. 01:49:49.000 --> 01:49:51.000 Whether you're doing fractionated 01:49:51.000 --> 01:49:56.000 Or results from your associated toxicity values 01:49:56.000 --> 01:49:58.000 Therefore, can qualify 01:49:58.000 --> 01:50:01.000 human risk. 01:50:01.000 --> 01:50:03.000 Now, the Elen Apple key messages. 01:50:03.000 --> 01:50:07.000 El Napple is a source of long-term vapor. 01:50:07.000 --> 01:50:09.000 sorbed and dissolved phases. 01:50:09.000 --> 01:50:15.000 An elound apple can be present in soil pores even though it's not visible in your wells. 01:50:15.000 --> 01:50:18.000 And like. 01:50:18.000 --> 01:50:26.000 it was mentioned, L-napple bodies typically stabilize really quick. 01:50:26.000 --> 01:50:34.000 Also, mobile and wells does not mean that the El Napple body is migrating or even recoverable. 01:50:34.000 --> 01:50:38.000 The only apple thickness in wells is affected by your soil type. 01:50:38.000 --> 01:50:41.000 And your water table fluctuations, as we saw in the video 01:50:41.000 --> 01:50:46.000 And the El Napa Hydrogeologic condition. 01:50:46.000 --> 01:50:53.000 Bar degradation processes to place your own apple source mass and help stabilize your own apple bodies. 01:50:53.000 --> 01:50:59.000 And your remedial technology selection is based on your concern, your saturation, your composition. 01:50:59.000 --> 01:51:04.000 And your static values. 01:51:04.000 --> 01:51:08.000 Here's the key message for PVI. 01:51:08.000 --> 01:51:15.000 Fiber degradation in the VATO zone limits or the potential of PVI and serves as the basis for lateral 01:51:15.000 --> 01:51:18.000 and vertical screening distances. 01:51:18.000 --> 01:51:25.000 And PVI are mainly associated with gasoline. 01:51:25.000 --> 01:51:30.000 And the proper identification of residual LNAPL sources is critical. 01:51:30.000 --> 01:51:34.000 Remember what we talked about sources in the home. 01:51:34.000 --> 01:51:37.000 Side characterization should focus on the fatal zone 01:51:37.000 --> 01:51:49.000 given a high likelihood that encountering gasoline related COCs in indoor air above the risk-based screening levels. 01:51:49.000 --> 01:51:55.000 Okay, I turn it back. 01:51:55.000 --> 01:52:03.000 Yeah, thanks, Lloyd. And thank you to all of our trainers today, including those that were in the background, keeping up with the 01:52:03.000 --> 01:52:08.000 question and answers, it's always great when we can answer over 30 questions for you guys. 01:52:08.000 --> 01:52:12.000 during the conversation we have here. 01:52:12.000 --> 01:52:24.000 So let's ask a couple more questions. I did just drop. I am going to put into the chat for you guys the feedback form and the link that's on the slide. 01:52:24.000 --> 01:52:34.000 I also want to mention that I will preview briefly for you that we do have some extra slides here at the end. You can download these slides. 01:52:34.000 --> 01:52:42.000 on the CLUIN training page that you came to today, scroll to the bottom and it should be under the materials link. 01:52:42.000 --> 01:52:48.000 But we did include some references for you to maintain. 01:52:48.000 --> 01:53:01.000 for your references. And I think the question that we're going to there were two that were very popular that we continued to kind of respond to in different ways. So Diana, I'm going to set you up first to talk a little bit about 01:53:01.000 --> 01:53:07.000 the conversation that was going on in the Q&A about silica gel cleanup. 01:53:07.000 --> 01:53:13.000 Thanks, Nicole. So the question that came in, and we've gotten this question a couple of times today, was 01:53:13.000 --> 01:53:19.000 Is it a good practice to just start your investigation right off the bat by using a silica gel cleanup method? 01:53:19.000 --> 01:53:25.000 And that's not necessarily a super straightforward answer. And the reason I say that is 01:53:25.000 --> 01:53:31.000 Number one, you need to check with the agency that has jurisdiction over your site because they may have specific requirements 01:53:31.000 --> 01:53:35.000 that you start with a more generalized bulk TPH method. 01:53:35.000 --> 01:53:38.000 But the other thing in general, too, to think about is 01:53:38.000 --> 01:53:45.000 Usually when we're doing an investigation, our goal is to get the best understanding of the conceptual site model that we possibly can. 01:53:45.000 --> 01:53:50.000 And really the best way to do that using some of the bulk TPH methods is to run them both ways. 01:53:50.000 --> 01:53:55.000 To run it with and without silica gel cleanup so you can get an understanding of 01:53:55.000 --> 01:53:59.000 what portion of your sample is hydrocarbon versus 01:53:59.000 --> 01:54:02.000 what portion may be your metabolites. 01:54:02.000 --> 01:54:11.000 And the answers to those questions really can help dictate and help you get a better understanding of what kind of transport properties you're dealing with. 01:54:11.000 --> 01:54:13.000 Because the metabolites are more mobile. 01:54:13.000 --> 01:54:19.000 And we'll also let you get a better handle of what your overall risk is from the petroleum component. 01:54:19.000 --> 01:54:22.000 of your 01:54:22.000 --> 01:54:29.000 of your sample. Just to hit on that a little bit, there really aren't toxicity values available for most of the metabolites. 01:54:29.000 --> 01:54:37.000 So when you do assess risk using a non-silica gel cleanup sample, you're treating your metabolites as if they were the same as petroleum. 01:54:37.000 --> 01:54:43.000 So that's another reason why it's good to get that distinction between what is metabolite versus what is petroleum. 01:54:43.000 --> 01:54:45.000 I hope that answered the question. 01:54:45.000 --> 01:54:52.000 It's not necessarily an all or none type of answer. You really do kind of have to look at your site and your agency. 01:54:52.000 --> 01:54:54.000 Great day, and thank you. 01:54:54.000 --> 01:55:02.000 And then we also had several questions come in about kind of state guidance and regulatory actions. 01:55:02.000 --> 01:55:09.000 I'm not sure which trainer responded last. Maybe it was Laura that would like to come out from the background. 01:55:09.000 --> 01:55:10.000 Oh, sure. 01:55:10.000 --> 01:55:18.000 Call you out on that one and just speak to us a little bit about kind of ITRC guidance and the state regulations. 01:55:18.000 --> 01:55:31.000 Sure, absolutely. Hey, everyone. So yeah, as a practicing risk assessor, you know, every state is different in the way that they have their TPH guidance. You know, they may not even have TPH guidance. 01:55:31.000 --> 01:55:38.000 But what's more important is that when you're working on a study in your specific state or regulating agency. 01:55:38.000 --> 01:55:45.000 you likely would have to follow those. So there's evolving information that you would maybe want to make sure you have 01:55:45.000 --> 01:56:02.000 in your back pocket when dealing with that. So, you know, I wouldn't recommend one guidance over another because you might have to actually, you know, work within a state guidance or a state regulating agency. So it's kind of a gray area. I don't really have any specific 01:56:02.000 --> 01:56:07.000 answers, but just you know consulting your state guidance that your site is in is probably the best 01:56:07.000 --> 01:56:08.000 place to start. 01:56:08.000 --> 01:56:15.000 The other thing I'm going to supplement what Laura said is that one of the things that really is probably the key when you're doing a TPH assessment 01:56:15.000 --> 01:56:22.000 is making sure that you're using an analytical method that matches your screening levels. 01:56:22.000 --> 01:56:28.000 And that's the other reason why it's very important to make sure that you have a handle on what jurisdiction you're working in. 01:56:28.000 --> 01:56:34.000 And using the documents and the methods for that jurisdiction because different methods were developed. 01:56:34.000 --> 01:56:37.000 with different screening levels in mind. 01:56:37.000 --> 01:56:42.000 So it's really just kind of key to make sure those match as well. 01:56:42.000 --> 01:56:57.000 That's great. And as a reminder, this was kind of the introduction to hydrocarbons. ITRC does have in-depth classes on all three of these topics. I have put the link to our list of archive trainings where you can go and find 01:56:57.000 --> 01:57:02.000 additional trainings just specific to all three of these 01:57:02.000 --> 01:57:08.000 hydrocarbons that we've talked about today. In addition to the hydrocarbons workshop 01:57:08.000 --> 01:57:13.000 that was put together as a series in 2022. 01:57:13.000 --> 01:57:20.000 And that link is here on the slide. So much more training and resources available from ITRC on this topic. 01:57:20.000 --> 01:57:23.000 But with that, I'll remind you that I've also put 01:57:23.000 --> 01:57:33.000 The link to the feedback form in the chat here as well. And we encourage you to go provide some feedback to us. And again, at the bottom of the 01:57:33.000 --> 01:57:42.000 form in the bottom right hand corner check the box to certify that you participated and your certificate of completion will be emailed to you. 01:57:42.000 --> 01:57:48.000 Thank you so much. If you have any other questions or follow up, please email ITRC at itrcweb.org. 01:57:48.000 --> 01:58:18.000 And we look forward to having you join us for another ITRC training in 2025. Thank you, everybody.