Michigan's fisheater cohorts: a prospective history of exposure.

Interest in environmental contaminants and their effect on human health emerged as a primary focus in the 1970s following the discovery of significant levels of mercury, dichloro diphenyl trichloroethane (DDT), and polychlorinated bihpenyls (PCBs) in recreationally caught Great Lakes fish. In response to these findings, the Michigan Department of Public Health, in 1971, initiated a series of "fisheater" cohort studies. These studies continue to be conducted today. The evolution of human exposure assessment by serum PCB determination parallels the evolution of more precise and sensitive analytical laboratory procedures over the past 25 years. Early work quantitated PCB with Aroclor 1254 standards. By 1980, the Webb and McCall packed-column method (Webb and McCall, 1972, 1973), which quantitates total PCB with Aroclor 1016 and 1260 standards, had gained the Association of Official Analytical Chemists (AOAC) approval and became the accepted method. This method was used in the 1978-1980 Michigan Great Lakes Fisheater Study, the first sizable study of this kind in the nation. The study confirmed that fisheaters had significantly more exposure (median 21.4 ppb vs 6.6 ppb) than controls. Toxicology studies have indicated the need to quantitate individual PCB congeners, in order to correlate exposure with possible toxicological and health outcomes. Today, capillary column gas chromatography and gas chromatography/mass spectrometry are used to search for trace components of the total PCB dose (Mullen et al., 1984). Because of the legacy of the earlier analytical data, Michigan also continues to conduct packed-column analysis for longitudinal comparisons. The Michigan fisheater study database and registry provide a significantly exposed and historic foundation for research testing health outcome hypotheses.