Climate Change and Exposure to Coastal Water Contamination

Background

Climate change will increase water vapor, due to higher mean temperatures, and trigger more intense precipitation events, which greatly increases the risk of pollutants entering coastal waters. Thus, bathers are at considerable risk of exposure to potentially harmful agents.

Methods

We collected water quality, beach attendance and water exposure data from all beaches in Southern California for 2000-2005. Due to the lack of independence of the observations the water quality was estimated by a linear model with a generalized least square estimator. The risk of gastrointestinal illness was calculated based on the predicted water quality for a given precipitation.

Results

Total precipitation of 1 inch per week can be attributed to 18.63 episodes of gastrointestinal illness per 1000 bathers at one of the large rivers; in contrast beaches next to smaller rivers are less at risk of contamination during a rain event, with 9.59 episodes per 1000 bathers. Under different climate change scenarios and the size of rivers, an extrapolation to a total precipitation of 4 inches per week indicates an increase of 23% to 66% more episodes, respectively.

Discussion

The analysis presented here provides estimates that will prove to be useful for policy decisions and environmental regulations under climate change scenarios. Consequences will not be restricted to the beach going public but will also extend to the tourism industry and the environment. Since global climate change will progress into the foreseeable future, strategies need to be developed to address this emerging public health concern.