PH13 Biomimetric Passive Sampling Devices for Predicting Bioavailability
Exhibit Hall
8:00 AM - Thursday, 13 November 2003
(PH136) Impact of seasonal variability on the bioavailability of PCBs and organochlorine pesticides in Portland Harbor, Oregon.
Anderson, Kim1, 2, Sethajintanin, Doolalai1, Johnson, Eugene1, 2, 1 Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, Oregon, USA2 Food Safety and Environmental Stewardship Program, Oregon State University, Corvallis, Oregon, USA
ABSTRACT- Water samples from an 18-mile stretch on the lower Willamette River, Oregon, including the Portland Harbor superfund site have been collected by semi-permeable membrane devices (SPMD) during different seasons in year 2001 and 2002. The upland industrial activities in the Harbor have been identified as potential sources of organochlorine compounds contamination based on their historic use. In addition, the upstream non-point source inputs are considered significant, especially during rainfall runoff events. Hence, understanding the variability (spatial and temporal) of bioavailable contaminants to natural cyclic process (e.g. seasonal variation) and episodic events (e.g. stormwater drainage) is necessary to fully understanding the impact of contaminants on water quality and aquatic bioaccumulation, particularly at the site such as Portland Harbor where contaminant load is high. The samplers have been deployed within the main river channel near stream outlets of various upstream land uses in order to sample the dissolved, bioavailable fraction of PCBs and organochlorine pesticides (p,p'-DDT, p,p'-DDD, p,p'-DDE and dieldrin). Preliminary data suggest differences of spatial and temporal distribution profiles of these contaminants over dry and wet events. Estimated river concentrations of PCBs and DDTs but not dieldrin were spatially different with regard to the upland land uses, in which low concentrations were observed at residential/undeveloped areas upriver and a significant increase in downtown/industrial areas. Seasonal variation impacted DDT river concentration estimates and the distribution ratio of DDT and its derivatives, as well as, PCB river concentration estimates and their homolog profiles. Influence of river condition (e.g. river flow, total/dissolved organic carbon) on the estimates of these contaminant levels in the river is discussed in this context. In addition, river concentration estimates of these chemicals are compared to the US EPA water quality criteria for fresh water to evaluate risk to aquatic community.
Key words: seasonal variability, organochlorines, bioavailability, Portland Harbor