Environmental contaminants in bald eagles in the Columbia River Estuary

Journal of Wildlife Management
By: , and 



Eggs, blood, and carcasses of bald eagles (Haliaeetus leucocephalus) and fish were collected and breeding success of eagles was monitored in the Columbia River estuary, 1980-87, to determine if contaminants were having an effect on productivity. High levels of dichloro diphenyl dichloroethylene (DDE), polychlorinated biphenyls (PCB's), and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) were found in eggs, blood from adults, and 2 eagle carcasses. Detectable levels of DDE and PCB's were found in blood of nestlings indicating they were exposed to these contaminants early in life. Increasing concentrations of DDE and PCB's with age also indicated accumulation of these contaminants. Adult eagles also had higher levels of mercury (Hg) in blood than subadults or young indicating accumulation with age. The high levels of DDE and PCB's were associated with eggshell thinning (x̄ = 10%) and with productivity (x̄ = 0.56 young/occupied site) that was lower than that of healthy populations (i.e., ≥1.00 young/occupied site). DDE and PCB's had a deleterious effect on reproduction of bald eagles in the estuary. The role dioxins play in eagle reproduction remains unclear, but concentrations in eagle eggs were similar to those in laboratory studies on other species where dioxins adversely affected hatchability of eggs. Probable sources of these contaminants include dredged river sediments and hydroelectric dams, and the proper management of each may reduce the amount of contaminants released into the Columbia River estuary.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Environmental contaminants in bald eagles in the Columbia River Estuary
Series title Journal of Wildlife Management
DOI 10.2307/3808994
Volume 57
Issue 1
Year Published 1993
Language English
Publisher Wiley
Contributing office(s) Oregon Cooperative Fish and Wildlife Research Unit
Description 10 p.
First page 10
Last page 19
Country United States
State Oregon, Washington
Other Geospatial Columbia River Estuary
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