BackgroundLow-income and minority communities often face disproportionately high pollutant exposures. The lead crisis in Flint, Michigan, has sparked concern about broader socioeconomic disparities in exposures to drinking water contaminants. Nitrate is commonly found in drinking water, especially in agricultural regions, and epidemiological evidence suggests elevated risk of cancer and birth defects at levels below U.S. EPA’s drinking water standard (10 mg/L NO3-N). However, there have been no nationwide assessments of socioeconomic disparities in exposures to nitrate or other contaminants in U.S. drinking water. The goals of this study are to identify determinants of nitrate concentrations in U.S. community water systems (CWSs) and to evaluate disparities related to wealth or race/ethnicity.MethodsWe compiled nitrate data from 39,466 U.S. CWSs for 2010–2014. We used EPA’s Safe Drinking Water Information System (SDWIS) to compile CWS characteristics and linked this information with both city- and county-level demographic data gathered from the U.S. Census Bureau. After applying multiple imputation methods to address censored nitrate concentration data, we conducted mixed-effects multivariable regression analyses at national and regional scales.Results5.6 million Americans are served by a CWS that had an average nitrate concentration ≥ 5 mg/L NO3-N between 2010 and 2014. Extent of agricultural land use and reliance on groundwater sources were significantly associated with nitrate. The percent of Hispanic residents served by each system was significantly associated with nitrate even after accounting for county-level cropland and livestock production, and CWSs in the top quartile of percent Hispanic residents exceeded 5 mg/L nearly three times as often as CWSs serving the lowest quartile. By contrast, the percent of residents living in poverty and percent African American residents were both inversely associated with nitrate.ConclusionsEpidemiological evidence for health effects associated with drinking water above 5 mg/L NO3-N raises concerns about increased risk for the 5.6 million Americans served by public water supplies with average nitrate concentrations above this level. The associations we observed between nitrate concentrations and proportions of Hispanic residents support the need for improved efforts to assist vulnerable communities in addressing contamination and protecting source waters. Future studies can extend our methods to evaluate disparities in exposures to other contaminants and links to health effects.Electronic supplementary materialThe online version of this article (10.1186/s12940-018-0442-6) contains supplementary material, which is available to authorized users.

Introduction Decreased sociability is a symptom of psychiatric conditions including autism-spectrum disorder and schizophrenia. Both of these conditions are associated with decreases in GABA function, particularly in the medial prefrontal cortex (PFC) and the basolateral amygdala (BLA); structures that are components of the social brain. Here, we determined if decreasing GABA transmission within either the PFC or the BLA decreases social behavior. Methods Rats were implanted with cannulae aimed at either the medial PFC or the BLA and then were tested on up to 4 behavioral tests following bilateral infusions of 0.5 μl bicuculline methiodide (BMI, a GABAA receptor antagonist) at doses of 0, 25, or 50 ng/μl. Rats were tested in the social interaction test, the social preference test, the sucrose preference test and for locomotor activity (BLA infusions only). Results Intra-BLA or PFC BMI infusions decreased the amount of time and the number of social interactions in the social interaction test. Further, in the social preference test, rats infused with 50 ng BMI no longer exhibited a preference to explore a social over a non-social stimulus. The change in sociability was not due to a change in reward processing or locomotor behavior. Discussion Decreasing GABA transmission in either the medial PFC or BLA decreased sociability. Thus, changes in GABA signaling observed in conditions such as autism or schizophrenia may mediate the social withdrawal characteristic of these conditions. Moreover, they suggest that social withdrawal may be treated by drugs that potentiate GABA transmission.

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Objectives. To evaluate the risk of death and injury in residential fires started on upholstered furniture, with a focus on open flame and cigarette-related heat sources. Methods. We used civilian death and injury data from 34 081 residential fires in the Massachusetts Fire Incident Reporting System from 2003 to 2016. We compared outcomes associated with fires that started on upholstered furniture ignited by smoking materials versus open flames. Results. Although fires starting on upholstered furniture were not common (2.2% of total fires), odds of death and injury were significantly higher in these fires than in fires started on other substrates. Among furniture fires, odds of death were 3 times greater when those fires were ignited by smoking materials than when ignited by open flames (odds ratio = 3.4; 95% confidence interval = 1.3, 10.9). Conclusions. Furniture fires started by smoking materials were associated with more deaths than were furniture fires started by open flames. Public Health Implications. Historically, furniture flammability regulations have focused on open flame heat sources, resulting in the addition of toxic flame retardants to furniture. Interventions to reduce deaths should instead focus on smoking materials.

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