Racial Disparities in Drinking Water Contamination Risk from Oil and Gas Wells in Los Angeles County

The Challenge

Approximately 500,000 residents in Los Angeles County live within half-a-mile of an active oil or gas well. Recent epidemiologic studies have suggested possible public health impacts associated with residential proximity to oil and gas development (ODG), and several U.S. studies have also found disproportionate oil and gas-related toxic exposure and health risks among racially and socioeconomically marginalized groups, suggesting environmental justice concerns.

Surface and ground water contamination are common exposure pathways that contribute to potential health effects associated with OGD activities. Most of the literature in this area, however, focuses on exposure to air pollutants and no studies to date have examined inequities in drinking water contamination risk associated with OGD activities, including in the context of L.A.

The Solution

The researchers identified oil and gas wells and drinking water supply wells across L.A. County through secondary data sources, conducted spatial analysis to estimate the potential contamination risk to community water systems (CWS) based on their water supply wells’ proximity to oil and gas wells, and characterized demographics of communities served by at-risk vs. not at-risk CWSs.

In the statistical analysis, they examined whether sociodemographic indicators (e.g., race/ethnicity, poverty) predict CWS contamination risk. They also examined whether historically redlined areas are more likely to face present day contamination risk.

Findings

• Higher percentages of people of color residents were associated with a higher likelihood of being served by an at-risk CWS (based on supply well proximity to an oil or gas well), and with a higher percentage of at-risk drinking water supply wells per CWS. 
• A higher percentage of historically redlined areas was associated with a higher likelihood of being served by an at-risk CWS and an increase in the percent of at-risk supply wells per CWS.

Next Steps

These results can help inform proposed regulation on setbacks in California, such as banning new oil drilling in close proximity to homes, schools and hospitals.