Publication Summary

Sediment and fish from Dillenbaugh Creek and the Chehalis River, near the American Crossarm and Conduit Superfund Cleanup site, were analyzed for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/PCDFs). PCDD/PCDFs in sediments and fish tissue downstream of the ACC site were significantly higher than background concentrations. PCDD/PCDFs in Dillenbaugh Creek sediments near the ACC were of concern for aquatic life and wildlife protection. PCDD/PCDFs in fish tissue from both Dillenbaugh Creek and the Chehalis River were of concern for human health protection, based on the National Toxics Rule fish tissue criterion and the 2000 EPA screening values for recreational and subsistence fishers.

Sediment and fish from Dillenbaugh Creek, located in Chehalis, Washington, were analyzed for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/PCDFs) in June 1998 by the Washington State Department of Ecology (Ecology). The analysis was part of a screening-level study to determine if residual PCDD/PCDFs exist in the vicinity of the American Crossarm and Conduit Company (ACC) Superfund site, cleaned up in the late 1980s.

PCDD/PCDF concentrations in sediments downstream of the ACC site were significantly higher than background areas in Dillenbaugh Creek and the Chehalis River. PCDD/PCDFs in sediments in Dillenbaugh Creek near the ACC exceeded guidelines for the protection of aquatic life and wildlife. Sediment concentrations are not a likely concern for human health, with the exception of one area just below the old ACC stormwater lagoon. Downstream transport of PCDD/PCDF-laden sediments into the Chehalis River from Dillenbaugh Creek did not appear to be significant.

PCDD/PCDF concentrations were significantly higher in fish tissue from Dillenbaugh Creek than from the Chehalis River. PCDD/PCDF levels in fish tissue from both Dillenbaugh Creek and the Chehalis River may be a concern for the protection of human health, based on the National Toxics Rule fish tissue criterion and EPA screening values for recreational and subsistence fishers.

As a secondary objective to the study, a screening method for PCDD/PCDFs called the Reporter Gene System (RGS) was evaluated for feasibility of use for future PCDD/PCDF studies. It was found to more accurately screen for PCDD/PCDFs in sediments and fish tissue at higher concentrations, than at the low to moderate concentrations commonly found in the environmental studies conducted by Ecology.

Link to EIM data for User Study ID DSER0006