Family clustering of PBB and DDE values among Michigan dairy farmers.

Family clustering of varying levels of serum PBB and DDE was evaluated for 62 Michigan families by using the mean and standard deviation for family units, ranked percentile comparison of family members, and correlation by linear regression of family members. The results indicate that levels of serum PBBs cluster within family units and for children within families. Serum DDE clustering within families occurs only for children. These findings are consistent with recent, interim PBB exposure, perhaps from a common dietary source for families. Serum DDE represents a lifetime, low-level exposure to DDT-DDE which has been both less prolonged and less intense for children. Thus similar levels, or clustered serum DDE, was observed for children within families.