Dataset Information

Inequalities in Public Water Arsenic Concentrations in Counties and Community Water Systems across the United States, 2006-2011.

ABSTRACT: Background: In the United States, nationwide estimates of public drinking water arsenic exposure are not readily available. We used the U.S. Environmental Protection Agency's (EPA) Six-Year Review contaminant occurrence data set to estimate public water arsenic exposure. We compared community water system (CWS) arsenic concentrations during 2006-2008 vs. after 2009-2011, the initial monitoring period for compliance with the U.S. EPA's 10??g/L arsenic maximum contaminant level (MCL).

Objective: Our objective was to characterize potential inequalities in CWS arsenic exposure over time and across sociodemographic subgroups.

Methods: We estimated 3-y average arsenic concentrations for 36,406 CWSs (98%) and 2,740 counties (87%) and compared differences in means and quantiles of water arsenic (via quantile regression) between both 3-y periods for U.S. regions and sociodemographic subgroups. We assigned CWSs and counties MCL compliance categories (High if above the MCL; Low if below) for each 3-y period.

Results: From 2006-2008 to 2009-2011, mean and 95th percentile CWS arsenic (in micrograms per liter) declined by 10.3% (95% CI: 6.5%, 14.1%) and 11.5% (8.3%, 14.8%) nationwide, by 11.4% (4.7%, 18.1%) and 16.3% (8.1%, 24.5%) for the Southwest, and by 36.8% (7.4%, 66.1%) and 26.5% (12.1%, 40.8%) for New England, respectively. CWSs in the High/High compliance category (not MCL compliant) were more likely in the Southwest (61.1%), served by groundwater (94.7%), serving smaller populations (mean 1,102 persons), and serving Hispanic communities (38.3%).

Discussion: Larger absolute declines in CWS arsenic concentrations at higher water arsenic quantiles indicate declines are related to MCL implementation. CWSs reliant on groundwater, serving smaller populations, located in the Southwest, and serving Hispanic communities were more likely to continue exceeding the arsenic MCL, raising environmental justice concerns. These estimates of public drinking water arsenic exposure can enable further surveillance and epidemiologic research, including assessing whether differential declines in water arsenic exposure resulted in differential declines in arsenic-associated disease. https://doi.org/10.1289/EHP7313.

SUBMITTER: Nigra AE

PROVIDER: S-EPMC7724967 | biostudies-literature | 2020 Dec

REPOSITORIES: biostudies-literature

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Inequalities in Public Water Arsenic Concentrations in Counties and Community Water Systems across the United States, 2006-2011.

Nigra Anne E AE Chen Qixuan Q Chillrud Steven N SN Wang Lili L Harvey David D Mailloux Brian B Factor-Litvak Pam P Navas-Acien Ana A

Environmental health perspectives 20201209 12

<h4>Background</h4>In the United States, nationwide estimates of public drinking water arsenic exposure are not readily available. We used the U.S. Environmental Protection Agency's (EPA) Six-Year Review contaminant occurrence data set to estimate public water arsenic exposure. We compared community water system (CWS) arsenic concentrations during 2006-2008 vs. after 2009-2011, the initial monitoring period for compliance with the U.S. EPA's 10 μg/L arsenic maximum contaminant level (MCL).<h4>Ob ...[more]

PMID: 33295795

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Project description:Inorganic arsenic is a known human carcinogen and is routinely detected in US community water systems (CWSs). Inequalities in CWS arsenic exist across broad sociodemographic subgroups. Our objective was to evaluate the county-level association between socioeconomic vulnerability and CWS arsenic concentrations across the US. We evaluated previously developed, population-weighted CWS arsenic concentrations (2006-2011) and three socioeconomic domains (the proportion of adults with a high school diploma, median household income, and the Centers for Disease Control and Prevention's overall socioeconomic vulnerability score) for 2,604 conterminous US counties. We used spatial lag models and evaluated the adjusted geometric mean ratio (GMR) of CWS arsenic concentrations per higher socioeconomic domain score corresponding to the interquartile range, and also evaluated flexible quadratic spline models. We also stratified by region and by United States Department of Agriculture Rural-Urban Continuum Codes to assess potential effect measure modification by region and rurality. Associations between socioeconomic vulnerability and CWS arsenic were modified by region and rurality and specific to socioeconomic domain. The fully adjusted GMR (95% CIs) of CWS arsenic per interquartile range higher proportion of adults with a high school education was 0.83 (0.71, 0.98) in the Southwest (corresponding to 17% lower arsenic with higher education), 0.82 (0.71, 0.94) in the Eastern Midwest (18% lower), and 0.65 (0.31, 1.36) in New England (35% lower). Associations between median household income and CWS arsenic were largely null. Higher overall socioeconomic vulnerability was significantly associated with lower CWS arsenic, but only in counties in the Central Midwest and those with total populations less than 20,000. Findings may reflect regional/local differences in both socioeconomic/socio-cultural context and public drinking water regulatory efforts. Across the US, individual domains of socioeconomic vulnerability (especially educational attainment) are more strongly associated with inequalities in CWS arsenic than the complex overall socioeconomic vulnerability index.

Project description:BackgroundThe US Environmental Protection Agency (EPA) currently sets maximum contaminant levels (MCLs) for ten metals or metalloids in public drinking water systems. Our objective was to estimate metal concentrations in community water systems (CWSs) across the USA, to establish if sociodemographic or regional inequalities in the metal concentrations exist, and to identify patterns of concentrations for these metals as a mixture.MethodsWe evaluated routine compliance monitoring records for antimony, arsenic, barium, beryllium, cadmium, chromium, mercury, selenium, thallium, and uranium, collected from 2006-11 (2000-11 for uranium; timeframe based on compliance monitoring requirements) by the US EPA in support of their second and third Six-Year Reviews for CWSs. Arsenic, barium, chromium, selenium, and uranium (detectable in >10% records) were included in the main analyses (subgroup and metal mixture analyses; arsenic data reported previously). We compared the mean, 75th percentile, and 95th percentile contaminant concentrations and the percentage of CWSs with concentrations exceeding the MCL across subgroups (region, sociodemographic county-cluster, size of population served, source water type, and CWSs exclusively serving correctional facilities). We evaluated patterns in CWS metal concentration estimate profiles via hierarchical cluster analysis. We created an online interactive map and dashboard of estimated CWS metal concentrations for use in future analyses.FindingsAverage metal concentrations were available for a total of 37 915 CWSs across the USA. The total number of monitoring records available was approximately 297 000 for arsenic, 165 000 for barium, 167 000 for chromium, 165 000 for selenium, and 128 000 for uranium. The percentage of analysed CWSs with average concentrations exceeding the MCL was 2·6% for arsenic (MCL=10 μg/L; nationwide mean 1·77 μg/L; n=36 798 CWSs), 2·1% for uranium (MCL=30 μg/L; nationwide mean 4·37 μg/L; n=14 503 CWSs), and less than 0·1% for the other metals. The number of records with detections was highest for uranium (63·1%). 75th and 95th percentile concentrations for uranium, chromium, barium, and selenium were highest for CWSs serving Semi-Urban, Hispanic communities, CWSs reliant on groundwater, and CWSs in the Central Midwest. Hierarchical cluster analysis revealed two distinct clusters: an arsenic-uranium-selenium cluster and a barium-chromium cluster.InterpretationsUranium is an under-recognised contaminant in CWSs. Metal concentrations (including uranium) are elevated in CWSs serving Semi-Urban, Hispanic communities independent of location or region, highlighting environmental justice concerns.FundingUS National Institutes of Health Office of the Director, US National Institutes for Environmental Health Sciences, and US National Institute of Dental and Craniofacial Research.

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Project description:BackgroundAdults in rural counties in the United States (US) experience higher rates broadly of cardiovascular disease (CVD) compared with adults in urban counties. Mortality rates specifically due to heart failure (HF) have increased since 2011, but estimates of heterogeneity at the county-level in HF-related mortality have not been produced. The objectives of this study were 1) to quantify nationwide trends by rural-urban designation and 2) examine county-level factors associated with rural-urban differences in HF-related mortality rates.Methods and findingsWe queried CDC WONDER to identify HF deaths between 2011-2018 defined as CVD (I00-78) as the underlying cause of death and HF (I50) as a contributing cause of death. First, we calculated national age-adjusted mortality rates (AAMR) and examined trends stratified by rural-urban status (defined using 2013 NCHS Urban-Rural Classification Scheme), age (35-64 and 65-84 years), and race-sex subgroups per year. Second, we combined all deaths from 2011-2018 and estimated incidence rate ratios (IRR) in HF-related mortality for rural versus urban counties using multivariable negative binomial regression models with adjustment for demographic and socioeconomic characteristics, risk factor prevalence, and physician density. Between 2011-2018, 162,314 and 580,305 HF-related deaths occurred in rural and urban counties, respectively. AAMRs were consistently higher for residents in rural compared with urban counties (73.2 [95% CI: 72.2-74.2] vs. 57.2 [56.8-57.6] in 2018, respectively). The highest AAMR was observed in rural Black men (131.1 [123.3-138.9] in 2018) with greatest increases in HF-related mortality in those 35-64 years (+6.1%/year). The rural-urban IRR persisted among both younger (1.10 [1.04-1.16]) and older adults (1.04 [1.02-1.07]) after adjustment for county-level factors. Main limitations included lack of individual-level data and county dropout due to low event rates (<20).ConclusionsDifferences in county-level factors may account for a significant amount of the observed variation in HF-related mortality between rural and urban counties. Efforts to reduce the rural-urban disparity in HF-related mortality rates will likely require diverse public health and clinical interventions targeting the underlying causes of this disparity.

Dataset Information

Inequalities in Public Water Arsenic Concentrations in Counties and Community Water Systems across the United States, 2006-2011.

Publications

Inequalities in Public Water Arsenic Concentrations in Counties and Community Water Systems across the United States, 2006-2011.

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