Passive Samplers On Semi-Permanent Moorings At Three Deep-Ocean Sites
Semipermeable membrane devices (SPMDs), low-density polyethylene (LDPE) strip samplers and polydimethylsiloxane (PDMS) strip samplers were mounted on semi-permanent moorings in Strait Mozambique, the Canary Basin (west of Africa), and the Irminger Sea (near Greenland) at depths between 0.1 and 5 km for 1 to 1.5 years. The samplers were analysed for polychlorinated biphenyls (PCBs), hexachlorobenzene (HCB), 4,4 DDE, and polyaromatic hydrocarbons (PAHs). Strong vertical gradients were observed in the Canary basin. By contrast, vertical gradients were minimal in the Irminger Sea. PAH concentrations were highest in the Canary basin. PAH concentrations increased with depth in Strait Mozambique. HCB concentrations were highest in the Irminger Sea, and concentrations of 4,4 'DDE did not vary much among sites. Differences in absorbed amounts between the various sampler types were related to sorption capacity. The in-situ sampling rates of the samplers was low, in accordance with the low flow velocities in the open ocean. The results show that passive samplers that are mounted on open-ocean moorings are valuable tools for evaluating the role of ocean circulation in the global distribution of organic contaminants.