CHARACTERIZATION OF A NEW SEDIMENT POREWATER PASSIVE SAMPLER FOR HYDROPHOBIC ORGANIC CONTAMINANTS

Abstract

Passive samplers have been proven as a useful tool for sampling the bioavailable fraction of hydrophobic organic contaminants (HOCs) in sediment. Polyethylene (PE) sheets used as passive samplers enable the quantification of a wide range of the bioavailable HOCs in situ and ex situ. The sediment of Newark Bay and Passaic River historically is a source of legacy HOCs such as polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) as well as emerging contaminates such as organophosphate esters (OPEs). Here we examine the distribution of PCBs, PCDD/Fs, and OPEs in Newark Bay utilizing a new form of passive sampling device based on a Danforth anchor that is not reliant on the use of divers for deployment. In the first sampling campaign in the Passaic River we compared our new anchor sampler to a previously used circular sampler. Minimal differences between the two samplers were found, confirming that the new sampler performed similarly to prior tools. The second campaign focused on Newark Bay, utilizing the anchor samplers for 10 bay sites and the circle samplers for 2 river sites. PCBs in the water column and sediment porewater of Newark Bay were evenly distributed with PCB 18 and 28 the dominant congeners at most sites. At all sites, porewater concentrations inferred from ex situ equilibrations exceeded those from the in situ passive samplers by 2–3 fold. The difference between the two sampling methods could be due to temperature differences or bioturbation. The concentration gradient between the water column and the sediment porewater implied that the sediment took up PCBs from the water column. OPEs were primarily detected in the lower part of Newark Bay suggesting that the Passaic and Hackensack Rivers were not sources of OPEs. Overall, we demonstrated the ability of our new sampling device to characterize legacy and emerging HOCs in sediment porewater and the water column and that this type of sampler could be effectively used at other contaminated sites.