摘要：With this article, we develop the Drinking Water Disparities Framework to explain environmental injustice in the context of drinking water in the United States. The framework builds on the social epidemiology and environmental justice literatures, and is populated with 5 years of field data (2005–2010) from California’s San Joaquin Valley. We trace the mechanisms through which natural, built, and sociopolitical factors work through state, county, community, and household actors to constrain access to safe water and to financial resources for communities. These constraints and regulatory failures produce social disparities in exposure to drinking water contaminants. Water system and household coping capacities lead, at best, to partial protection against exposure. This composite burden explains the origins and persistence of social disparities in exposure to drinking water contaminants. “Isn’t the issue of contaminated water just an issue of economies of scale, where small systems face the biggest problems?” “In talking about environmental injustices and contaminated drinking water, are you implying that someone is deliberately polluting people’s water?” “If there is no statistical correlation between race, class, and water quality, doesn’t that mean there is no injustice?” —Questions commonly encountered during fieldwork in the San Joaquin Valley Hundreds of small, rural communities in California and across the United States rely on unsafe drinking water sources that their modest means cannot mitigate. Research and grassroots efforts have drawn attention to high levels of contaminants in California’s San Joaquin Valley (the Valley) 1 ; to inadequate services and infrastructure in US–Mexico border colonias 2 and rural communities in the South 3,4 ; and to bacteriological and chemical contamination in unregulated drinking water sources in the Navajo Nation. 5 Our own earlier research, conducted between 2005 and 2011, established that race/ethnicity and socioeconomic class were correlated with exposure to nitrate and arsenic contamination and noncompliance with federal standards in community water systems. 6,7 But why do social disparities in access to safe water exist and persist in a country where most of the population has access to piped, potable water? A rich understanding of how disparities in access to safe drinking water are produced and maintained is essential for understanding environmental justice concerns and developing effective public health interventions. In this article, we highlight the mechanisms through which natural, built, and sociopolitical factors, along with state, county, and community actors, create a composite and persistent drinking water burden in the Valley. This research reflects the call by environmental justice scholars 8,9 for more historically informed work on the causes and consequences of environmental injustice (i.e., disproportionate environmental burdens by race and class). The drinking water and environmental justice literature has focused on how unequal access to infrastructure drives unequal access to safe drinking water. Wilson et al. have shown that disparities in “basic amenities” drive adverse health outcomes, especially in conjunction with poorly enforced health laws and building codes. 4,10 VanDerslice’s infrastructure-oriented framework posits that the extent to which any aspect of water infrastructure—natural, built, or managerial—differs by racial or income disparities drives disparities in water quality, reliability, and cost. 11 The literature also notes that small water systems are vulnerable to inadequate regulatory protection, 12 and to uneven monitoring and reporting. 13,14 Studies on equity and the built environment have discussed how historical and structural conditions shape lack of access to safe drinking water. These conditions include selective enforcement of drinking water regulations, 15 noncompliance with federal standards, 16,17 inequities in access to funding, 18 and (the absence of) a community’s political power in accessing a safe water supply. 19 Research has also shown that cost of service extension and low ability to pay drive inadequate service provision 2 ; that municipalities provide or deny access to basic services by determining which areas to annex or exclude from their city boundaries 4,10,20 ; and that segregation allows such determinations to continue. 21 Thus the environmental justice and built environment literatures highlight the many causal factors of social disparities, but, to date, do not offer a comprehensive framework for tracing both the origins and persistence of disparities in exposure. Here, social epidemiology offers a theoretical foundation for our analysis. In particular, an ecosocial epidemiological approach underscores the need to (1) explore the social production, or origins, of health disparities 22,23 ; (2) uncover the multilevel factors that drive the distribution of disease, 24,25 or, in our case, exposure; and (3) highlight the “agency and accountability” of multilevel actors in creating these disparities and embodiments of disease. 22,24 Our work draws on several social epidemiology–inspired frameworks. These frameworks discuss how race, class, social factors, 26,27 and multiple levels of decision-making 22 can have an impact on exposure pathways. 28 Sexton et al. 26 expanded the traditional exposure–disease paradigm 29 used in environmental health by positing that differential health risks may be associated with race and socioeconomic class because of exposure (e.g., proximity to source) and susceptibility-related (e.g., gender) attributes. Gee and Payne-Sturges refined Sexton et al.’s work with a multilevel perspective that explores how vulnerability intersects the exposure–disease paradigm. 27 deFur et al. complemented this approach by showing that vulnerability can have an impact on exposure pathways between environmental factors and receptors (i.e., individual, community, or population) and response pathways between receptors and outcomes. 28 In sum, social epidemiology frameworks emphasize how and why health disparities may arise, and, to some extent, why they persist. They do not, however, focus specifically on drinking water. We present the Drinking Water Disparities Framework, which builds on the social epidemiology and the infrastructure-centric frameworks discussed previously in 3 main ways. First, our framework describes which infrastructural factors shape disparities, as VanDerslice 11 does, but we add the role of social and political factors. VanDerslice’s article hypothesizes that disparities in water-related infrastructure vary by race and class, and supports this claim through the published literature; we use primary field data to trace how and why these disparities exist and also persist, as a consequence of built, natural, and sociopolitical factors. For instance, we show how the historical marginalization of poor communities, coupled with poor source water quality, determines the condition of their physical infrastructure and results in exposure. Second, in line with Wilson, 30 we highlight the role of multilevel actors, but we emphasize how specific decisions at different levels, past or present, intentional or accidental, drive disparities in access to drinking water. For example, we show how municipal redlining, limited county oversight, and low household finances together impede mitigation of contaminated water. Third, our multilevel framework extends the classic exposure–disease paradigm 29 to show that water system and household coping mechanisms, intended to alleviate exposure, create a feedback loop through which disparities in drinking water quality may be exacerbated. In this way, the framework shows how drinking water disparities comprise both external stressors and susceptibility to them, as well as the capacity, or lack thereof, to cope. 28,31 Thus, we emphasize the role of historical and structural factors, and trace the mechanisms through which these lead to exposure disparities. We argue that these structural factors are not deterministic, but that communities and individuals exercise agency within the structures that constrain them. The extent of this agency also has an impact on exposure. A framework that pays attention to history as well as contemporary processes, and to structures as well as agency, reveals both the pathways to unsafe water and the points of leverage at which exposure to contaminants can be reduced. Five years of primary data collection in California’s San Joaquin Valley provide the empirical grounding for our framework. This richly nuanced data set reveals not only the role of multilevel actors in shaping disparities, but also the lived experiences of households and communities who struggle for safe water. Ultimately, our framework outlines a “composite burden,” composed of exposure to contaminants and inability of socially vulnerable communities to mitigate contamination. We argue that this composite burden leads to persistent exposures and social disparities in exposure to poor drinking water.
