Description
Due to a rapid increase in population, Tijuana, Mexico has struggled to maintain and meet sewage infrastructure demands. As a result, untreated sewage discharges into the Tijuana River and flows into the Tijuana River Valley and the Tijuana Estuary in California, eventually flowing into the Pacific Ocean. Unfortunately, sewage contaminated water drains to nearby beaches and communities, increasing the risk of contracting waterborne disease. Due to inconsistent and infrequent water quality monitoring and fecal contamination studies in the San Diego-Tijuana border, the extent and impact of sewage releases to the Tijuana River Valley and Tijuana River Estuary are not well understood. This study assesses the potential impacts of fecal contamination in this region by quantifying total coliform and E. coli counts using the IDEXX method. Results show a high presence of total coliform and E.coli bacteria in surface water samples commonly found in untreated sewage. Values were lower at the Tijuana River Estuary than those from sampling sites closest to the border. Moreover, it was determined that no correlation was found between coliform concentrations and precipitation or total flows. It was also determined using longitudinal coliform data obtained from TRNERR that there was no statistical significance between dry weather and wet weather precipitation. The data from this study along with previous monitoring studies provide evidence of the extent of fecal contamination found in surface waters in the Tijuana River Valley and Tijuana Estuary. The presence of high levels of fecal contamination in surface water even during dry weather suggests treatment systems in the region are not effectively capturing or treating all transboundary flows spilling into the Tijuana River. Ultimately this study found that a more robust and collaborative approach among policymakers and stakeholders while also addressing our current discourse on border environmental politics, is necessary to effectively improve the sewage issue in this binational region.
