Fish PCB concentrations and consumption patterns among Mohawk women at Akwesasne

A study was conducted to determine concentrations of polychlorinated biphenyls (PCBs) in local fish and to establish patterns of fish consumption of nursing Mohawk women residing near three industrial hazardous waste sites. From 1986 to 1992, 97 Mohawk women were interviewed within one month postpartum. A comparison group consisted of 154 nursing Caucasians. Samples of 348 local fish were analyzed for PCBs. The results indicated that fish in the Mohawk area, especially those collected offshore from the waste sites, had been contaminated with PCBs. The dietary data showed a greater past prevalence of local fish consumption among Mohawk mothers, with an overall annual mean of 23.5 local fish meals more than one year before the pregnancy compared with 14.1 for the control women (p < 0.001). The prevalence of consumption by the Mohawks, however, declined over time, resulting in overall mean rates of 9.2 local fish meals one year or less before pregnancy, and 3.9 meals per year during pregnancy (p < 0.001 for linear trend). Compared to the Mohawks, significantly fewer control women stopped eating local fish, and their rates declined less sharply. A secular trend was also observed in the overall rate of consumption during pregnancy for the Mohawks, with those who gave birth in 1986-1989 having a mean of 10.7 local fish meals per year during pregnancy, compared with means of 3.6 and 0.9 respectively for women who delivered in 1990 and 1991-1992 (p < 0.05 for linear trend). No such trend was apparent for the controls. No background variable was significantly related to the rate of local fish consumption among the Mohawks, but a decrease over time in the rate of local fish consumption was greater among those Mohawks who ate the most local fish initially (r = -0.76, p < 0.001), or who also reduced their alcohol intake during pregnancy (r = 0.35, p < 0.05). Mohawks were also more likely than the controls to trim the fat, remove the skin from, and fry and fish they ate during the past year. These dietary changes may be the result of advisories that have been issued over the past decade recommending against the consumption of local fish by pregnant and nursing Mohawk women. Such changes, if sustained, should reduce their exposure to PCBs and correspondingly the potential for adverse health effects.