Eating fish contaminated with DDTs and PCBs does not make people sick right away. The more contaminated fish you eat, the greater the amount of chemicals that build up in your body over time.
Health problems associated with increased exposure to these chemicals include cancer, liver disease and developmental effects, as well as effects on the immune and endocrine systems. During pregnancy and lactation, mothers can pass DDTs and PCBs on to their infants. Because chemicals affect development, children through adolescence, elderly people and women of childbearing age are more sensitive to the harmful chemicals and should be especially careful.