Author: Fageh, Noor Ali
Exposure to endocrine disrupting chemicals (EDCs) potentially leads to adverse health effects in wildlife and humans. In this study, a panel of genetically modified yeast bioassays containing human estrogen, androgen, or progesterone receptors along with the appropriate steroid responsive elements of the β-galactosidase reporter gene were used to screen for EDCs in samples collected from various river and stream sites close to cattle farms and agricultural operations in Surrey and Langley. Water and sediment samples were collected on three different occasions either before or after a rainy period. The yeast screening bioassays were reproducible, accurate, and precise. They also showed calibration linearity and low detection limits for the EDC marker chemicals. Results of the studies showed high levels of androgen-, estrogen-, glucocorticoid- and aromatic hydrocarbon-like chemicals in the water and sediment samples from Surrey and Langley. As expected, the samples collected near dairy farms and agricultural operations contained much higher levels of EDCs compare to sites far away from farming and agricultural activities. The EDCs in the water samples were generally lower in concentrations than the sediments. Selected water samples were further analyzed for estrogens and androgens chemically using a gas chromatography-mass spectrometer. The water samples were found to contain estradiol, estrone, nonylphenol, bisphenol A, and androstendion with mean concentrations ranging from 0.041 to 30.10 ng/ml. Our studies demonstrate that animal farms and agriculture activities account for significant amounts of EDCs released into the aquatic environment at Surrey and Langley.
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Thesis advisor: Law, Francis
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