“‘Thus otters serve as biomonitors – organisms that contain information on the quantitative and qualitative aspects of the environment – of wildlife exposure,’ according to a new study. They also serve as biomonitors for human health because the same toxic chemicals found in otters have also been found in people who eat contaminated fish.

The study published in the journal ‘Ecotoxicology and Environmental Safety’ found high concentrations of chemical compounds in the livers of 23 otters in central Illinois.

Especially troubling were the highest concentrations of dieldrin ever reported in otters anywhere in the United States, said lead author Samantha Carpenter, a wildlife technical assistant at the University of Illinois, Urbana-Champaign.

Dieldrin is one of the organochlorine insecticides banned in 1978. More than three decades later, high levels of the chemicals remain in river sediments and accumulate in the fish that otters and people may eat.

The compound has been linked to neurological, behavioral and immune-suppression problems in wildlife. Scientific studies disagree on adverse human effects, but some studies have linked dieldrin to asthma, Parkinson’s disease, Alzheimer’s disease and breast cancer, Carpenter said.”