Patients with continued exposure may experience blurred vision, followed by impaired speech and loss of hearing. Acute and prolonged exposure could result in paralysis and eventual death. Fish advisories for women of child bearing years, pregnant or nursing mothers, and young children are greatly restricted because the fetus and children under 6 years of age are more susceptible to a wide range of mental and physical defects. Unlike mercury that is slowly expelled from the body, PCBs are more stable substances that are poorly excreted by humans. Prolonged exposure to PCBs also may adversely affect fetal development in humans.
Fish absorb contaminants throughout their lifetime from food they eat.
Older and larger fish generally will have higher levels of contamination compared to younger, smaller fish. Larger, older predatory fish such as northern pike and walleye have the greatest exposure to contaminants. Fatty fish that accumulate contaminants from sediments along the lake or stream bottom also may have higher levels of pollutants. PCBs and dioxins concentrate in fat of fatty fish such as catfish, carp, and lake trout. Although fat removal from fish can reduce PCB and dioxin levels, fat trimming will not reduce mercury that is tightly bound to proteins in fish.