A new study finds that drought-related drinking water contamination is disproportionately affecting Latino communities in California.
Among the contaminants plaguing these water systems are arsenic and nitrates, which are linked to an increased risk of a variety of diseases, according to a study published Wednesday.American Journal of Public HealthResearch has shown that such diseases include cancer, cardiovascular disease, developmental disorders and birth defects.
Community water systems, which often distribute water with high concentrations of contaminants, are located in areas that lack sufficient public infrastructure and socio-political and financial support, the authors note, while drought conditions typically reduce dilution of water sources, causing spikes in contaminant concentrations.
Study authors from the University of California, Santa Barbara, used water sample data, historical drought records, agricultural intensity, and socio-demographic characteristics of local residents to analyze trends in arsenic and nitrification concentrations in the region’s surface and drinking water from 2007 to 2020.
Finally, they found that community water systems serving predominantly Latino residents had consistently higher and more variable levels of both contaminants compared to systems serving primarily other populations.
“Drought increased nitrate concentrations in majority-Latino neighborhoods, and the effect was doubled in CWS, which is more than 75 percent Latino,” said lead author Sandy Sam, a doctoral candidate at the University of California, Santa Barbara.statementUse the acronym Community Water System.
“Arsenic concentrations in surface water sources also increased for all groups during the drought period,” she added.
After taking a closer look at the details of contamination levels, Sam and his colleagues found that nitrates in groundwater-sourced drinking water in these areas had increased from 2.5 milligrams per litre in 1998 to a peak of 3.1 milligrams per litre in 2018.
In contrast, in non-Latino majority areas, levels fell from 2.1 milligrams per liter to 1.8 milligrams per liter over the same period.
The researchers concluded that drought conditions exacerbated existing disparities in nitrate concentrations in drinking water from surface sources. This particular spike was especially pronounced in very small, privately run community water systems, according to the study.
Regarding arsenic, the authors found that drought increased overall concentrations of this contaminant in drinking water from surface water sources in both majority-Latino and non-majority areas.
Sam surmised that water systems serving primarily Latino communities are likely “not mitigating elevated nitrate levels during droughts, which exacerbates existing disparities.”
“This may reflect a lack of treatment infrastructure, resource constraints, or other operational or technological differences,” she added, highlighting the need for related policy initiatives.
Sam warned that while the study focused only on nitrates and arsenic, these communities “may also be at increased risk of contamination from other sources, such as pesticides, waste dumps and manufacturing plants, due to stressors such as droughts, floods and other natural events.”
