| The risk of waterborne infections acquired from the consumption of contaminated water is related to changes in source water fecal contamination, which is often influenced by land-use and hydro-meteorological conditions in the surrounding watershed. The impact of land-use composition on surface water contamination was explored in order to determine the risk of surface water contamination associated with land-use change. Highest contamination was observed in watersheds characterized by more than 12.5% agricultural and more than 1.6% urban land (mean fecal coliform (FC) concentration of these 5 sites = 135 CFU 100ml -1 while the British Columbia (BC) raw water quality guideline = 100 CFU 100ml-1). Contamination increased exponentially, and violated BC raw water quality guidelines with greater frequency, in relation to greater agricultural land in the upstream watershed. Additional factors, such as sewage treatment plants, low dilution in smaller streams, and higher temperatures were also associated with greater contamination. These results indicate the high level of risk posed by agricultural and urban development and the need for source water protection. |
