U.S. EPA Contaminated Site Cleanup Information (CLU-IN)

U.S. Environmental Protection Agency
U.S. EPA Technology Innovation and Field Services Division

Fractured Bedrock Project Profiles

Last Updated: December 31, 2010

Point of Contact:
Carol Stein
290 Broadway
New York NY 10007-1866 
Tel: 212-637-4181 
Email: stein.carol@

Ciba Geigy - Hercules Plant Site
Glens Falls, NY


Groundwater beneath the site flows laterally through shallow relatively permeable fill and lacustrine sand. A
clay layer underlies most of the site and this together with the underlying bedrock unit forms a lower boundary to the shallow flow zone. The underlying bedrock has three progressively deeper, highly fractured bedrock water-bearing
zones known as Horizons A, B, and C.

Targeted Environmental Media:
  • - Dense Non-aqueous Phase Liquids (DNAPLs)
  • - Fractured Bedrock


The site is on the banks of the Hudson River and the plume in the overburden and shallow fractured rock zone discharge to it.

Major Contaminants and Maximum Concentrations:
  • - Cyanide (50,000 µg/L)
  • - Chromium (20,000 µg/L)

Site Characterization Technologies:

No technologies selected.

Remedial Technologies:

  • - Pump and Treat
Organic contamination for this site is given in terms of total volatile organic chemicals. The maximum value reported in the reference document is 20,000 ug/L in the overburden groundwater and 10,000 ug/L in the "B" bedrock fracture zone.

The overburden plume is being contained with a french drain type system.

All of the collected water is co-mingled and diverted through a force main to the point that it is sampled and discharged to the municipal system. Although industrial wastewater was formerly treated on-site (at the Pre-Treatment Plant), the groundwater extraction system water meets the criteria for discharge to the POTW, and is not treated.
Remediation Goals:

New York Groundwater Quality Standards which are typically 5 ug/L for VOCs.


Fourteen groundwater recover wells are installed in the A horizon bedrock and 6 are in the B horizon bedrock.

In comparison to the pre-remedy groundwater data, 2008 groundwater data shows that Horizon A bedrock chromium and VOCs have decreased significantly at all locations. Cyanide has decreased overall across the site, but one well had a cyanide concentrations just slightly below the August 2001 (pre-remedy) level. In Horizon B, north of the railroad tracks, VOC and chromium have been reduced by an order of magnitude, cyanide by 30-50%. South of the railroad tracks, similar reductions in chromium and cyanide have occurred, with a larger reduction in VOCs.

Top of Page