Bathers exposed to microbiological contamination in coastal waters have an excess risk of gastrointestinal and respiratory illness. The disease burden associated with this risk may be considerable in Southern California, where 50 million annual beach visitors recreate in coastal waters that receive billions of gallons of polluted discharges from nearby urban areas.
The goal of this study was to estimate the risk and disease burden of gastrointestinal and respiratory illness from bathing in the coastal waters of Southern California and to identify areas and periods of especially high risk.
For 2000 – 2004, gastrointestinal and respiratory illness rates were estimated with a simulation model that utilized water quality, beach attendance, and bathing rate data, along with three published dose-response relationships.
An estimated 689,000 to 4,003,000 episodes of gastrointestinal illness and 693,000 episodes of respiratory illness occurred each year at Southern California beaches during the study period. The majority of illnesses (57% – 80%) occurred during the summer season. A relatively small proportion of beaches (12 of 67) accounted for half of all illnesses. Only small fluctuations in the annual health burden were observed.
Coastal water contamination is a serious health risk for bathers at Southern California beaches. Although coastal waters are more contaminated during the winter, most contamination related illnesses occur during the summer months due to large seasonal increases in bathing populations. California's marine water contact standards may be inadequate to protect the health of bathers
