Evaluation of population-level ecological risks of dioxin-like polychlorinated biphenyl exposure to fish-eating birds in Tokyo Bay and its vicinity
✍ Scribed by Wataru Naito; Mariko Murata
- Publisher
- Society of Environmental Toxicology and Chemistry
- Year
- 2007
- Tongue
- English
- Weight
- 323 KB
- Volume
- 3
- Category
- Article
- ISSN
- 1551-3777
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✦ Synopsis
Abstract
Population‐level assessments of the ecological risks of dioxin‐like polychlorinated biphenyl (PCB) exposure to fish‐eating birds in Tokyo Bay and its vicinity were performed to judge the need for risk management measures to protect aquatic wildlife from dioxin‐like PCB contamination. Egg mortality risk and changes in the population growth rate (λ) in relation to the contamination levels of dioxin‐like PCBs in eggs of gray heron (Ardea cinerea), great cormorant (Phalacrocorax carbo), osprey (Pandion halieaetus), and kingfisher (Alcedo atthis) were determined by integrating the results of exposure analysis, effect analysis, and a life‐history model for each species. The egg mortality risks for the gray heron, great cormorant, osprey, and kingfisher populations were calculated to be 5.8, 6.8, 12, and less than 1%, respectively. The estimated λ for those populations were calculated to be 1.061, 1.405, 1.024, and 1.131, respectively. The percentage changes in λ for those populations were estimated to be 1.2, 2.0, 1.6, and less than 1%, respectively. Our results implied that the levels of dioxin‐like PCBs observed in the Tokyo Bay area alone would not have significant population‐level effects on the fish‐eating bird populations. It is concluded that along with the trend toward decreasing dioxin and dioxin‐like PCB levels in Tokyo Bay, no urgent need exists for risk‐reduction measures to protect fish‐eating bird populations against dioxin‐like PCBs.