Polybrominated diphenyl ethers (PBDEs) in aquatic organisms from Lake Michigan
Abstract
This research of polybrominated diphenyl ethers (PBDEs) incorporated three studies to investigate PBDE biotransformation, bioaccumulation, and biomagnification in aquatic organisms from Lake Michigan. First, diets spiked with four nominal concentrations (control, 0.1, 1, and 2 μg/g-diet) of BDE-209 were fed to laboratory-reared lake whitefish (Coregonus clupeaformis ) for 30 days. Less than 10% uptake efficiency was found in treated groups. Hepatic BDE-209 concentrations in the 1 and 2 μg/g groups were significantly higher than in the control group (1.25 and 5.80 nmol/g-lipid compared to 0.183 nmol/g-lipid). The concentration of BDE-209 detected in the tissues of the control group resulted from BDE-209 in the base diets. The liver was the primary organ where BDE-209 accumulated, and BDE-206 was the major product from the debromination of BDE-209. Additionally, otolith increments for the 2 μg/g group were decreased, which implies a negative impact on lake whitefish growth during BDE-209 exposure. Second, Chinook salmon (Oncorhynchus tshawytscha), lake trout (Salvelinus namaycush), and lake whitefish as well as invertebrates (plankton and Diporeia spp.) were collected from Lake Michigan in 2006. Liver and muscle tissues from the fish were separately analyzed for BDE-47, 99, 100, 153, 154, and 209. Geometric mean concentrations of PBDE in fish tissues ranged from 0.911 to 2.02 nmol/g-lipid; BDE-209 ranged from 0.192 to 1.28 nmol/g-lipid. BDE-47, 99, and 209 comprised 80-94% of the total PBDE concentration (on a molar basis). Bioaccumulation of each brominated congener was species and size-dependant. Third, biomagnification of PBDEs in a Lake Michigan food web was examined through analysis of invertebrates combined with the above fish data. Stable nitrogen and carbon isotope ratios were used to determine trophic levels. We observed biomagnification on BDE-47, 99, and 100 and biotransformation of BDE-209 within this food web. The calculated biomagnification factors for all specific predator/prey relationships were larger than one (implying biomagnification was occurring) for BDE-47 and 100 but less than one for BDE-209. Evidence of BDE-209 accumulation was shown in both laboratory-reared lake whitefish and free-ranging aquatic organisms from Lake Michigan. In addition, biotransformation of BDE-209 occurred not only in lake whitefish but also within the food web of Lake Michigan.
Degree
Ph.D.
Advisors
Hua, Purdue University.
Subject Area
Biogeochemistry|Environmental engineering|Limnology
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