The association between local fish consumption and DDE, mirex, and HCB concentrations in the breast milk of Mohawk women at Akwesasne.

A study was conducted to assess the extent to which the consumption of local fish contaminated with p,p'-dichlorodiphenyl dichloroethylene (p,p'-DDE), mirex, and hexachlorobenzene (HCB) has impacted the concentrations of these compounds in the milk of nursing Mohawk women residing along the St. Lawrence River. From 1986 to 1992, 97 Mohawk women were interviewed, and each donated a one-time sample of at least 50 ml of breast milk. The comparison population consisted of 154 Caucasians from other rural areas in New York State. After adjustment for potential confounders, Mohawk mothers who gave birth from 1986 to 1990 had significantly higher geometric mean p,p'-DDE milk concentrations than did the control group, but no significant differences were observed from 1991 to 1992. In contrast, mirex was significantly elevated among the Mohawks throughout the study period, while HCB showed no difference at any point. Mohawk women with the greatest estimated cumulative lifetime exposure to p,p'-DDE from local fish consumption had a significantly higher geometric mean milk level of that compound relative to control women, but no differences in mirex or HCB concentrations in breast milk by local fish consumption were found. The reduction in breast milk p,p'-DDE concentrations among the Mohawk women from 1986 to 1990 parallels a corresponding decrease in local fish consumption, and may be the result of the advisories that have been issued over the past decade recommending against the consumption of local fish by pregnant and nursing Mohawk women. Elevations in the concentrations of mirex in the breast milk of the Mohawks are consistent with the fact that it is a common contaminant in the region and throughout the Lake Ontario-St. Lawrence River Basin.

Fish consumption and breast milk PCB concentrations among Mohawk women at Akwesasne.

A study was conducted to determine the relation between the consumption of contaminated local fish and concentrations of total polychlorinated biphenyls (PCBs) and 68 PCB congeners in the milk of nursing Mohawk women residing near three hazardous waste sites. From 1986 to 1992, 97 Mohawk women were interviewed and donated at least 50 ml of breast milk. The comparison population consisted of 154 Caucasians. After adjustment for potential confounders, Mohawk mothers who gave birth in 1986-1989 had a geometric mean milk total PCB concentration of 0.602 ppm (fat basis) compared with 0.375 ppm for the control group (p = 0.009). These Mohawk women also had significantly higher geometric mean concentrations of nine congeners. Beginning in 1990, however, there were no significant differences between the Mohawk women and the comparison group. Estimated cumulative lifetime exposure from local fish consumption was significantly related to milk total PCB and to three congeners only among those Mohawks who gave birth from 1986 to 1989. The reduction in breast milk PCB concentrations parallels a corresponding decrease in local fish consumption and may be the result of the advisories that have been issued over the past decade recommending against the consumption of local fish by pregnant and nursing Mohawk women.

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.