Social Disparities in Nitrate-Contaminated Drinking Water in California’s San Joaquin Valley

Abstract

Background: Research on drinking water in the United States has rarely examined disproportionate exposures to contaminants faced by low-income and minority communities. This study analyzes the relationship between nitrate concentrations in community water systems (CWSs) and the racial/ethnic and socioeconomic characteristics of customers.Objectives: We hypothesized that CWSs in California’s San Joaquin Valley that serve a higher proportion of minority or residents of lower socioeconomic status have higher nitrate levels and that these disparities are greater among smaller drinking water systems.Methods: We used water quality monitoring data sets (1999–2001) to estimate nitrate levels in CWSs, and source location and census block group data to estimate customer demographics. Our linear regression model included 327 CWSs and reported robust standard errors clustered at the CWS level. Our adjusted model controlled for demographics and water system characteristics and stratified by CWS size.Results: Percent Latino was associated with a 0.04-mg nitrate-ion (NO3)/L increase in a CWS’s estimated NO3 concentration [95% confidence interval (CI), –0.08 to 0.16], and rate of home ownership was associated with a 0.16-mg NO3/L decrease (95% CI, –0.32 to 0.002). Among smaller systems, the percentage of Latinos and of homeownership was associated with an estimated increase of 0.44 mg NO3/L (95% CI, 0.03–0.84) and a decrease of 0.15 mg NO3/L (95% CI, –0.64 to 0.33), respectively.Conclusions: Our findings suggest that in smaller water systems, CWSs serving larger percentages of Latinos and renters receive drinking water with higher nitrate levels. This suggests an environmental inequity in drinking water quality.

Resilient Governance of Water Regimes in Variable Climates: Lessons from California’s Hydro-Ecological Zones

“…Depending on researchers' disciplines, their work has passed scholarly review in ecology, economics, political science, geomorphology, hydrology, sociology, planning, geography, engineering and archeology. Scientific and professional purposes have included, e.g., the survival of a species or habitat [13][14][15][16][17], the production of food [23,29], safe and equitable water supply for mass consumption [21,52], flood and drought hazard reduction [22,42] and forest water storage and supply [35,36,[53][54][55] Sites and scales have extended from localized and isolated circumstances in specific habitats of California's Russian River [15,16,29,30] and ancient settlements in the Levant [56] to large scale technocratic modes of governance in California [21,22,42] the European Union [42] and, the Ganges-Brahmaputra Basin [57][58][59][60][61][62][63].…”

Water marginalization at the urban fringe: environmental justice and urban political ecology across the North–South divide

“…For instance, in one of the first papers on social disparities related to water contamination, Calderon et al (1993) investigate how race and class affect exposure to water contamination. Similarly, Balazs et al (2012Balazs et al ( , 2011 show that low-income Latino communities in the San Joaquin Valley face not only disproportionate exposure to contaminants such as arsenic and nitrates, but also unequal regulatory compliance challenges.…”

Economic Feasibility of Irrigated Agricultural Land Use Buffers to Reduce Groundwater Nitrate in Rural Drinking Water Sources

“…In 2007, the exceedances that occurred in the SJV accounted for approximately 74% of all well MCL exceedances recorded in California [44,45] have indicated a significant relationship between MCL exceedances and proportion of Latino population served among small (less than 200 connections) community water systems (CWS). The poverty rate among US-born Latinos is significantly higher than that of US-born self-identified "whites" (14% versus 9%), and at 27%, foreign-born Latinos experience poverty more than any other demographic group in California [46].…”

“…Latinos represent about 39% of the total population and comprise the majority population in many municipalities in the SJV [39]. Given these demographics, the findings of [45] suggest that households in poverty tend to be more affected by NO3-contaminated water supplies. At the same time, small CWSs are less able to fund NO3 treatment technology or water replacement activities than larger facilities.…”