Farming and Prostate Cancer

TLDR

Untreated storm‑drain runoff contaminates coastal waters—a problem common to many coastal regions yet previously unstudied in large epidemiologic cohorts. This cohort study was conducted to assess health risks associated with swimming in ocean water impacted by untreated urban runoff. Exposure was quantified by distance from storm drains, bacterial indicators (total/fecal coliforms, enterococci, E. coli), and direct detection of enteric viruses.

Abstract

Waters adjacent to the County of Los Angeles (CA) receive untreated runoff from a series of storm drains year round. Many other coastal areas face a similar situation. To our knowledge, there has not been a large-scale epidemiologic study of persons who swim in marine waters subject to such runoff. We report here results of a cohort study conducted to investigate this issue. Measures of exposure included distance from the storm drain, selected bacterial indicators (total and fecal coliforms, enterococci, and Escherichia coli), and a direct measure of enteric viruses. We found higher risks of a broad range of symptoms, including both upper respiratory and gastrointestinal, for subjects swimming (a) closer to storm drains, (b) in water with high levels of single bacterial indicators and a low ratio of total to fecal coliforms, and (c) in water where enteric viruses were detected. The strength and consistency of the associations we observed across various measures of exposure imply that there may be an increased risk of adverse health outcomes associated with swimming in ocean water that is contaminated with untreated urban runoff.