Organic Chemistry Section
Low Level PCBs, PBDEs and Pesticides

The laboratory routinely analyzes for a variety of environmental contaminants at the part per billion (µg/L or µg/kg) level. However, environmental chemistry and statistical modeling are constantly evolving and calling for ever lower detection limits. Over the past few years the regulatory and environmental monitoring communities have developed a need for extremely low level pesticide and PCB congener analysis of surface water. In order to meet this need, the laboratory has developed methodologies which allow for detection of PCB congeners and organochlorine pesticides at sub part per trillion levels (picograms/Liter).

The WSLH has adapted and refined methodologies developed by EPA-Duluth, the University of Wisconsin - Superior, and the UW - Madison Water Chemistry program. These methods involve surface water sampling with glass fiber filters and XAD-2 resin columns which adsorb dissolved organic contaminants. The sampling media are soxhlet extracted and analyzed by GC/ECD. The very low detection levels are achieved mainly through the extraction and analysis of large sample volumes (80 - 160 liters). Due to the large sample size, particular attention is paid to minimizing background contamination.

The WSLH has participated in a number of collaborative projects involving other organizations. Descriptions of a few of the projects are included below. You may also click here for a list of the low level contaminants measured at the WSLH.

The Lake Michigan Tributary Study

A recent project involved the study of pollutants flowing into Lake Michigan. In conjunction with various agencies including the Environmental Protection Agency (EPA), the Wisconsin Department of Natural Resources (WDNR), the University of Wisconsin - Madison, and the United States Geological Survey (USGS), the WSLH participated in an ongoing study of Lake Michigan tributaries. This study was part of the larger Lake Michigan Mass Balance project.

The goal of this particular project was to quantify the loading to Lake Michigan of selected critical trace metal and toxic organic chemicals from eleven major tributaries. The WSLH Organic Chemistry Department participated in the PCB congener and pesticide analysis of the tributaries, while the WSLH - Inorganic Chemistry Unit worked on metals analysis.

The Michigan DEQ Surface Water Study

Beginning in April 1998, the Michigan Department of Environmental Quality (MDEQ) implemented a water quality trend monitoring program. An important component of this program calls for the assessment of changes over time in concentrations of PCB congeners and selected bioaccumulative chemicals of concern (BCCs). The assessment data is being used to evaluate the effectiveness of efforts aimed at reducing concentrations of pollutants. Because specialized analytical methods were necessary, the MDEQ came to the WSLH to do the work.

The USGS collected 69 samples from five inland rivers and each of the Great Lakes connecting channels. The sampling took place from April through October 1999. In addition nine qaulity assurance samples were analyzed. PCB congener analysis was performed on all samples, while analysis of the BCCs (cis & trans-chlordane, DDT/DDD/DDE, hexachlorobenzene, alpha & gamma-BHC, cis & trans-nonachlor and oxychlordane) was done on a select subset of the samples. The data generated by samples taken in the summer of 1999 was scheduled to be complete by March 2000.

The Fox River Deposit Removal Project

In late 1998 the WDNR began a sediment remediation project on the lower Fox River. The WSLH participated in the project by conducting the PCB congener testing of the water column before, during, and after the dredging portion of the remediation. The WSLH portion of the analytical work was completed in early 1999. For more information on this project click here.

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Last updated 11/13/03