Production of PCBs was halted in the United States by the late 1970s. Because PCBs were used so extensively and take a long time to break down, they are found everywhere. PCBs accumulate in the fat of people and animals. Lead is a naturally occurring element and exists at low levels throughout our environment. Decades of hard-rock mining activity in the region have caused the waters and sediments entering the Spokane River from Lake Coeur d Alene to be high in lead and other metals.
Fish take in contaminants from the water they live in and the food they eat.
Older, larger, predator fish tend to have more PCBs and lead than younger, smaller fish because these contaminants build up in fish over time. The same contaminants can build up in humans, too. Pregnant women and women considering pregnancy should carefully follow the meal limits given in Table 1. The fetus is particularly susceptible to the harmful effects of lead and PCBs when the mother eats contaminated fish. Such effects can include learning problems that appear during childhood years.