Abstract Title

Session S-01B: PCBs in the Green/Duwamish Watershed

Keywords

Toxics

Start Date

30-4-2014 10:30 AM

End Date

30-4-2014 12:00 PM

Description

PCBs are a major contaminant of concern in the Lower Duwamish Waterway Superfund Site. King County wants to understand the relative contributions of atmospheric deposition to the Lower Duwamish Waterway. Thus, King County conducted a bulk air deposition study in 2011/2012 and a second study in 2013 to examine how PCB deposition varied with land use. Seven stations were passively sampled along a gradient of development from the Lower Duwamish River Valley to Enumclaw for metals, PAHs, PCBs and dioxin/furans; however, this presentation will focus on the PCB results. Samples were collected intermittently over approximately a year period for the first study and over nine months for the second study. Samples were analyzed for 209 PCB congeners. When possible, sampling stations were selected at Puget Sound Clean Air Agency monitoring stations. Stations during the first study included two in the Lower Duwamish River Valley (Duwamish and South Park), one at Beacon Hill, two in Kent and one in Enumclaw. Stations in the second study included three in the Lower Duwamish Valley (Duwamish, South Park and Georgetown) and one at Beacon Hill. These stations varied with different mixes of land use (industrial, commercial, residential) and development (urban, suburban and rural). Daily deposition rates were calculated for each sample and compared between stations and over different time periods. Multivariate analysis was used to test for significance of environmental factors in affecting deposition rates. Differences in the relative contributions of different PCB congeners to the total were also examined among stations. Results from the first study showed total PCB deposition was higher at the Lower Duwamish River Valley stations than the others. The results from 2013 will be compared with those of the first study.

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Apr 30th, 10:30 AM Apr 30th, 12:00 PM

Spatial and temporal differences and congener content in bulk air deposition of PCBs in the Green/Duwamish River Basin

Room 608-609

PCBs are a major contaminant of concern in the Lower Duwamish Waterway Superfund Site. King County wants to understand the relative contributions of atmospheric deposition to the Lower Duwamish Waterway. Thus, King County conducted a bulk air deposition study in 2011/2012 and a second study in 2013 to examine how PCB deposition varied with land use. Seven stations were passively sampled along a gradient of development from the Lower Duwamish River Valley to Enumclaw for metals, PAHs, PCBs and dioxin/furans; however, this presentation will focus on the PCB results. Samples were collected intermittently over approximately a year period for the first study and over nine months for the second study. Samples were analyzed for 209 PCB congeners. When possible, sampling stations were selected at Puget Sound Clean Air Agency monitoring stations. Stations during the first study included two in the Lower Duwamish River Valley (Duwamish and South Park), one at Beacon Hill, two in Kent and one in Enumclaw. Stations in the second study included three in the Lower Duwamish Valley (Duwamish, South Park and Georgetown) and one at Beacon Hill. These stations varied with different mixes of land use (industrial, commercial, residential) and development (urban, suburban and rural). Daily deposition rates were calculated for each sample and compared between stations and over different time periods. Multivariate analysis was used to test for significance of environmental factors in affecting deposition rates. Differences in the relative contributions of different PCB congeners to the total were also examined among stations. Results from the first study showed total PCB deposition was higher at the Lower Duwamish River Valley stations than the others. The results from 2013 will be compared with those of the first study.