| The combined stresses of municipal wastewater and agricultural run-off are common in river basins globally, although they are generally evaluated separately. Endocrine disrupting compounds (EDCs) are introduced to rivers from municipal wastewater and agricultural run-off. Along river gradients, I measured changes in vitellogenin levels in longnose dace to assess a physiological response to exposure to estrogenic compounds, a group of EDCs. Vitellogenin levels increased downstream of municipalities and areas influenced by agriculture. Female-biased sex ratios were detected in the Oldman River, which suggests severe endocrine disruption. I also sampled river water for 28 organic contaminants, which includes many estrogenic compounds, from 23 sites on three rivers. Organic contaminants were detected at every site, which indicates multiple activities within the river basins influence water quality. This thesis demonstrates the presence of organic contaminants spatially and a biological response to the cumulative impacts of municipalities and agriculture on rivers. |
