Many adults who regularly eat PCB-contaminated fish from Lake Michigan have problems with simple memory and learning tests, according to a study led by Susan Schantz at the University of Illinois. On the basis of these new results, current advice on eating fish from the Great Lakes, which focuses mainly on protecting the pregnant woman and fetus, may need to be revised.

Although commercial fishing in Lake Michigan is federally regulated, sportfishing is not. The researchers studied one group of adults, who annually ate more than 24 lbs of fish caught in Lake Michigan and another who ate less than 6 lbs. The 180 subjects ranged from 49 to 86 years old.

The team found that levels of PCBs and 10 other contaminants were markedly elevated in the blood of those who consumed a large percentage of fish in their diets, and this group was more likely to have problems learning and remembering verbal information. For example, they had difficulties recalling a story told to them 30 minutes previously and memorizing a 16-item shopping list read out loud to them. But their visual–spatial abilities, and their ability to pay attention and plan were not affected. Other contaminants in the fish such as DDE (a DDT metabolite), mercury, and lead, did not affect intellectual performance.

Exposure to low levels of PCBs in the womb has already been linked to learning disabilities in children, but Schantz believes this is the first study to find that adults with high levels of PCBs in their blood may suffer from intellectual impairment. (Environ. Health Perspect. 2001, 109 (6) 605–611). —MARIA BURKE