River otters as biomonitors for organochlorine pesticides, PCBs, and PBDEs in Illinois

Samantha K Carpenter,Nohra E Mateus-Pinilla,Kuldeep Singh,Andreas Lehner,Damian Satterthwaite-Phillips,Robert D Bluett,Nelda A Rivera,Jan E Novakofski

doi:10.1016/j.ecoenv.2013.07.028

Abstract

The North American river otter (Lontra canadensis) is a biomonitor for organohalogenated compounds (OHCs) associated with a wide range of deleterious health effects in wildlife and humans. We determined concentrations of twenty OHCs in livers of 23 river otters salvaged by the Illinois Department of Natural Resources from 2009 to 2011, determined sex-dependent distribution of OHCs, and compared our results to the reported concentrations of four OHCs in Illinois river otters from 1984 to 1989. Since these contaminants have been banned for over 30 years, we predicted smaller mean concentrations than those previously reported in Illinois otters. We detected eleven of twenty OHCs; PCBs (polychlorinated biphenyls), dieldrin, and 4,4′-DDE (dichlorodiphenyldichloroethylene) were present in the greatest mean concentrations. We report the largest mean concentration of dieldrin to date in the liver of North American river otters (mean: 174, range: 14.4–534 parts per billion wet wt [ppb]). Mean PCB concentrations were significantly higher in males (mean: 851; range: 30–3450ppb) than females (mean: 282; range: 40–850ppb; p=0.04). Mean concentrations of dieldrin were greater than those detected in otters from 1984 to 1989 (mean: 90; range: 30–130ppb; p<0.05). Our results suggest OHC exposure remains a concern. Future research in Illinois should focus on evaluating OHCs exposures, particularly dieldrin, at the watershed level.

Highlights

Organohalogenated compounds (OHCs) are of global concern due to their environmental persistence, bioaccumulative potential, and adverse effects on humans and wildlife (Bernanke and Kohler, 2008; Mnif et al, 2011)
The ranges of concentrations for the five OHCs detected in the 23 otters were wider in males
We detected a lower mean concentration and range (1.1 ppb; lower detection limit (LDL)–2.0 ppb) than previously reported (10.5 ppb; 10.1–35.3 ppb) (Stansley et al, 2010). While it is unclear whether this concentration can be associated with adverse health effects in otters, potential health risks associated with polybrominated diphenyl ethers (PBDEs) exposure include thyroid hormone disruption, neurological effects, and cancer in laboratory animals (McDonald, 2002)

Summary

Introduction

Organohalogenated compounds (OHCs) are of global concern due to their environmental persistence, bioaccumulative potential, and adverse effects on humans and wildlife (Bernanke and Kohler, 2008; Mnif et al, 2011). OHCs include three industrial chemical groups, polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), as well as organochlorine pesticides (OCPs). OCPs are further divided into five groups: dichlorodiphenyltrichloroethane (DDT) and its analogs, isomers of benzene hexachloride (BHC), cyclodiene insecticides (including heptachlor, chlordane, and aldrin), caged structures (e.g. mirex and chlordecone) and toxaphene (Smith, 1991). Cyclodiene insecticides were applied in Illinois cornfields from 1953 until their use was banned in 1978. Peak use occurred in 1967 when approximately 5.6 out of 10 million acres of corn soil in Illinois were treated. Of the OCPs applied to Illinois soil, aldrin was applied extensively; an estimated 44.9 million acres of corn soil were treated between 1956 and 1977 (Steffey et al, 1984). The main epoxide of aldrin is dieldrin (Koerner et al, 1999). The authors found that dieldrin concentrations in the brains of five out of 57 raptors approached or exceeded the diagnostic lethal levels of 4000–5000 parts per billion (ppb)

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