Impairments of Memory and Learning in Older Adults Exposed to Polychlorinated Biphenyls via Consumption of Great Lakes Fish

Environmental Health Perspectives, June, 2001 by Susan L. Schantz, Donna M. Gasior, Elena Polverejan, Robert J. McCaffrey, Anne M. Sweeney, Harold E.B. Humphrey, Joseph C. Gardiner

Measures of Exposure

Several weeks after completion of the neuropsychological assessment battery, we collected a blood sample from 96% (n = 180) of the participants for residue analysis. One sample was not obtained because of a collapsed vein, one subject died before a sample could be collected, and six subjects refused the blood draw. The samples were analyzed for PCBs and 10 other contaminants including DDE, polybrominated biphenyls, hexachlorobenzene, oxychlordane, dieldrin, mirex, mercury, and lead (11,28). We analyzed PCBs, DDE, and other organochlorines in serum by gas chromatography. Lead and mercury were analyzed in whole blood by atomic absorption spectrophotometry. Serum or blood concentrations of the contaminants have been reported previously (12,28). Four chemicals, PCBs, DDE, lead, and mercury were higher in the heavy fish eaters than in those who ate little or no fish, but PCBs and DDE clearly emerged as the primary contaminants of concern and are, therefore, the focus of this report. The mean levels of each of the four contaminants in each of the 12 enrollment cells defined by age, sex, and fish-eating status are shown in Table 3. The levels of PCBs and DDE were markedly elevated in heavy fish eaters, both relative to age- and sex-matched non-fish eaters and relative to levels typically observed in the population at large (29). Non-fish eaters, while also exposed to PCBs and DDE, had much lower levels of both chemicals. Only 15 participants (8.4%) had serum PCB levels below the detection limit of 3.0 ng/g, and only 6 (3.4%) had DDE levels below the detection limit of 1.0 ng/g.