Latinos have higher exposure to nitrate-contaminated drinking water, study finds

San Joaquin Valley communities with large Latino populations are exposed to disproportionately high levels of the agricultural chemical nitrate through their drinking water, a team of researchers at the University of California, Berkeley found in a study published in the June issue of Environmental Health Perspectives.

The study was an interdisciplinary collaboration between Carolina Balazs; Rachel Morello-Frosch, a professor with the Department of the Environmental Science, Policy and Management and the School of Public Health; Alan Hubbard, a professor with the School of Public Health; and Isha Ray, a professor with the Energy and Resources Group—all of UC Berkeley.

The study explored whether there were demographics-related inequalities in nitrate exposure of residents in 327 drinking water systems throughout the San Joaquin Valley’s eight counties, from 1999 to 2001. This is the first peer-reviewed study in the United States to directly analyze the relationship between nitrate contamination, race and class.

Nitrate is a chemical used as fertilizer by farmers, and also derives from animal manure, human septic systems and the atmosphere. When ingested via drinking water it can cause reproductive harm to women, cause the often fatal “blue baby syndrome,” and may be associated with thyroid cancer, among other health effects, according to the U.S. EPA and numerous epidemiological studies.

Researchers found that across all eight counties studied, there was a positive correlation between water systems that served larger proportions of Latinos and increased nitrate levels in the water systems, and that Latinos in the San Joaquin Valley are disproportionately exposed to higher levels of nitrates in drinking water. In addition, researchers found that this relationship is strongest in smaller water systems.

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By Ann Brody Guy