A study funded and conducted by the Washington State Department of Ecology evaluated the CLAM for monitoring PCBs, PBDEs and dioxins in the Spokane River. We are pleased to share with you the detailed report written by DOE staff.
Study Location and Design
“In support of ongoing efforts to address levels of concern for PCBs, dioxins and furans, and other toxics in the Spokane River, Ecology conducted a study to evaluate several types of sample collection methods and analytical methods for toxics monitoring in the Spokane River during fall 2012 through spring 2013. Details further explaining the purpose and scope of the Ecology study are outlined in the Quality Assurance Project Plan (QAPP) for the study (Era-Miller, 2013).
The study focused on PCBs, dioxins and furans, PBDEs, cadmium, lead, and zinc. Environmental samples included surface water collected both by composite hand grabs and through 24-hour filtration in the field and sediments collected by sediment traps deployed for several months at a time.”
Discussion and Summary of Results
“The CLAM collection method for PCB and PBDE congeners in the Spokane River is a good surrogate for grab sampling. PCB and PBDE congeners gave a clear environmental signal and had good precision of field triplicates. PCB Aroclor method EPA 8082 is a poor choice to use with the CLAM samplers due to detection limits above environmental concentrations in the Spokane River. Both PBDE methods EPA 1614 (measures for 38 congeners) and EPA 8270 (14 congeners), could be used with CLAM samplers because the congeners representing >80% of the total PBDE concentrations in the Spokane River (PBDEs 47, 99 and 209) are reported in both analytical methods.”
“PCB congeners in the CLAM samples gave a clear environmental signal with results that were 1-2 orders of magnitude higher than the laboratory method blank concentration. Precision of samples deployed in triplicate was excellent.”
“Detection limits for many of the individual PBDE congeners reached down into the sub pg/L range for EPA 1614 and down into the sub ng/L range for EPA 8270. Even with this difference in detection levels and the difference in number of congeners analyzed between the two analytical methods, results between the two sets of triplicate data were highly comparable.”