Ground Water Systems’ Progress in Meeting National Drinking Water Goals

The Drinking Water State Revolving Fund Helps Ground Water Systems Deliver Public Health Protection

Proposed Drinking Water Standards for PFAS

Progress in Providing Safe Drinking Water

Sociodemographic inequalities in uranium and other metals in community water systems across the USA, 2006–11: a cross-sectional study

This report describes the available drinking water quality monitoring data on the Centers for Disease Control and Prevention (CDC) National Environmental Public Health Tracking Network (Tracking Network). This surveillance summary serves to identify the degree to which ten drinking water contaminants are present in finished water delivered to populations served by community water systems (CWS) in 24 states from 2000 to 2010. For each state, data were collected from every CWS. CWS are sampled on a monitoring schedule established by the Environmental Protection Agency (EPA) for each contaminant monitored. Annual mean and maximum concentrations by CWS for ten water contaminants were summarized from 2000 to 2010 for 24 states. For each contaminant, we calculated the number and percent of CWS with mean and maximum concentrations above the maximum contaminant level (MCL) and the number and percent of population served by CWS with mean and maximum concentrations above the MCL by year and then calculated the median number of those exceedances for the 11-year period. We also summarized these measures by CWS size and by state and identified the source water used by those CWS with exceedances of the MCL. The contaminants that occur more frequently in CWS with annual mean and annual maximum concentrations greater than the MCL include the disinfection byproducts, total trihalomethanes (TTHM), and haloacetic acids (HAA5); arsenic; nitrate; radium and uranium. A very high proportion of exceedances based on MCLs occurred mostly in very small and small CWS, which serve a year-round population of 3,300 or less. Arsenic in New Mexico and disinfection byproducts HAA5 and TTHM, represent the greatest health risk in terms of exposure to regulated drinking water contaminants. Very small and small CWS are the systems’ greatest difficulty in achieving compliance.

BackgroundFew studies of environmental justice examine inequities in drinking water contamination. Those studies that have done so usually analyze either disparities in exposure/harm or inequitable implementation of environmental policies. The US EPA’s 2001 Revised Arsenic Rule, which tightened the drinking water standard for arsenic from 50 μg/L to 10 μg/L, offers an opportunity to analyze both aspects of environmental justice.MethodsWe hypothesized that Community Water Systems (CWSs) serving a higher proportion of minority residents or residents of lower socioeconomic status (SES) have higher drinking water arsenic levels and higher odds of non-compliance with the revised standard. Using water quality sampling data for arsenic and maximum contaminant level (MCL) violation data for 464 CWSs actively operating from 2005–2007 in California’s San Joaquin Valley we ran bivariate tests and linear regression models.ResultsHigher home ownership rate was associated with lower arsenic levels (ß-coefficient= −0.27 μg As/L, 95% (CI), -0.5, -0.05). This relationship was stronger in smaller systems (ß-coefficient= −0.43, CI, -0.84, -0.03). CWSs with higher rates of homeownership had lower odds of receiving an MCL violation (OR, 0.33; 95% CI, 0.16, 0.67); those serving higher percentages of minorities had higher odds (OR, 2.6; 95% CI, 1.2, 5.4) of an MCL violation.ConclusionsWe found that higher arsenic levels and higher odds of receiving an MCL violation were most common in CWSs serving predominantly socio-economically disadvantaged communities. Our findings suggest that communities with greater proportions of low SES residents not only face disproportionate arsenic exposures, but unequal MCL compliance challenges.

Surveillance for Waterborne Disease Outbreaks Associated With Drinking Water - United States, 2011-2012.

Background: Very little is known about the quality of drinking water in US correctional facilities (e.g. detention centers, prisons, jails, etc.), which disproportionately detain people of color. The current Environmental Protection Agency’s maximum contaminant level (MCL) for arsenic in public drinking water is 10 µg/L. We estimated drinking water arsenic concentrations in US correctional facilities to determine if incarcerated persons remain at risk for chronic, elevated water arsenic exposure relative to the non-incarcerated US population.Methods: We obtained 230,158 arsenic monitoring records for 37,098 community water systems (CWSs) from the Environmental Protection Agency’s Third Six Year Review of Contaminant Occurrence dataset (covering 2006-2011). We compared six-year average arsenic concentrations in all CWSs versus CWSs exclusively serving correctional facilities. We separately evaluated the Southwestern US (where groundwater arsenic concentrations are relatively high) versus non-Southwestern US.Results: Average six-year water arsenic concentrations were higher for CWSs exclusively serving correctional facilities in the Southwest (6.41 µg/L, 95% CI 3.48, 9.34) compared to all other Southwestern CWSs (3.11 µg/L, 95% CI 2.97, 3.24) and to other CWSs across the rest of the US (1.39 µg/L, 95% CI 1.35, 1.42). Compared to other US CWSs and to other Southwestern CWSs, correctional facility CWSs in the Southwest were more likely to report six-year arsenic averages exceeding 10 µg/L (1.6%, 5.8%, and 26.1% of systems, respectively).Conclusions: CWSs exclusively serving correctional facilities in the Southwestern US reported average water arsenic concentrations twice as high as those reported by all other CWSs in the Southwest, and more than a quarter reported six-year averages exceeding the EPA’s regulatory MCL. Strict enforcement of the EPA’s drinking water regulations and a comprehensive review of other drinking water contaminants in CWSs serving correctional facilities is necessary to protect the health and human rights of all incarcerated persons in the US.

BACKGROUND AND AIM: The US Environmental Protection Agency (EPA) sets maximum contaminant levels (MCLs) for 9 metals/metalloids in public drinking water systems. Beyond arsenic, no nationwide exposure estimates for public drinking water currently exist for these contaminants. Our objective was to estimate exposure to metals in community water systems (CWSs) across the US, to determine if sociodemographic or regional inequalities in these exposures exist, and to identify patterns of exposure for these metals as a mixture. METHODS: We evaluated routine compliance monitoring records for antimony, barium, beryllium, cadmium, chromium, mercury, selenium, thallium, and uranium collected from 2006-2011 (2000-2011 for uranium) by the US EPA in support of the Third Six Year Review for 37,915 CWSs. We focused our analysis on barium, chromium, selenium, and uranium (as arsenic has been reported previously and other metals were mostly undetected), comparing the mean contaminant concentration and the percent of CWSs with MCL excedances across subgroups (US region, sociodemographic county-cluster, size of population served, source water type, and correctional facilities). We evaluated patterns in metal exposure profiles via hierarchical cluster analysis, which also included published CWS arsenic estimates. RESULTS:The percentage of CWSs exceeding the MCL was highest for uranium (3.1% MCL of 30 µg/L, nationwide mean 4.37 µg/L), but lower than previously reported arsenic (2.6%). 75th, 95th percentiles for uranium, chromium, barium, and selenium concentrations were highest for CWSs serving {Semi-Urban, Hispanic} communities, small CWSs, CWSs reliant on groundwater, and those located in the Southwest, similar to previous CWS arsenic findings. Hierarchical cluster analysis revealed four clusters, including an arsenic-uranium-selenium cluster. CONCLUSIONS:{Semi-Urban, Hispanic} communities experience higher average concentrations of metal contaminants, including uranium and arsenic, in public drinking water. Uranium is an under-recognized contaminant in CWSs. Cluster analyses revealed that arsenic and uranium may co-occur in groundwater sources serving CWSs. KEYWORDS: exposure, environmental justice, environmental disparities, water quality

Arsenic in drinking water poses a threat to public health world-wide. In March 2001, the EPA revised the maximum contaminant level (MCL) for arsenic in drinking water downward from 50 µg/L to 10 µg/L and required all U.S. small community water systems (CWSs) and non-community water systems (NCWSs) to comply by 23 January 2006. Much of the financial burden associated with complying with and maintaining this new drinking water MCL was shouldered by local community governments. For example, the Walker River Paiute Tribe operated a CWS on the Walker River Paiute Indian Reservation that needed upgrading to meet the new arsenic MCL. In collaboration with the Walker River Paiute Tribe, we conducted a study to assess whether reducing the arsenic concentration in drinking water to meet the new MCL reduced the arsenic body burden in local community members who drank the water. Installing a drinking water treatment to remove arsenic dramatically reduced both the drinking water concentrations (to below the current EPA MCL of 10 µg/L) and the community members’ urinary concentrations of total As, AsIII, and AsV within a week of its full implementation. Additional assistance to small water systems to sustain new drinking water treatments may be warranted.

Patterns and predictions of drinking water nitrate violations across the conterminous United States

ABSTRACTMotivated partly by concerns about cancer, the U.S. Congress in 1986 amended the Safe Drinking Water Act (SDWA) by requiring that community water systems monitor 81 chemicals and remove those detected at concentrations above health-based standards. No prior research has used the resulting 30 years of monitoring data to analyze cancer risks from chemicals in US drinking water. To fill this gap, this paper uses chemical monitoring data from North Carolina's (NC's) 2,120 community water systems along with a risk assessment approach commonly applied in global burden of disease studies to quantify cancer risks of regulated chemicals in drinking water. The results indicate that 0.30% of NC cancer deaths are attributable to regulated drinking water contaminants and that the average annual individual risk is 7.2 × 10−6. More than 99% of this risk arises from disinfection by-products, with the remaining risk mostly attributable to arsenic and alpha particle radiation. In no water system does the combined risk from chemicals other than disinfection by-products, arsenic, or alpha particles exceed 10−4. The results suggest that regulated chemicals pose very low cancer risks and that risks from chemicals other than disinfection by-products, arsenic, and alpha particles are negligible in NC community water systems.

Arsenic in US correctional facility drinking water, 2006–2011

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.

Evaluations of the costs and benefits of US drinking water standards typically consider only a single contaminant or class of contaminants. However, the US Environmental Protection Agency (USEPA) is in the process of formulating and implementing multiple new regulations, and drinking water systems will be expected to comply with all of them simultaneously. The joint effects of different regulations are not necessarily the sum of the effects of the individual regulations. In some cases, treating for one contaminant may remove other contaminants. In other instances, treating for one contaminant (e.g., pathogens) may make it more difficult to comply with regulations for other contaminants (e.g., disinfection byproducts). A simulation model was developed to assess the national costs and benefits of compliance with multiple drinking water standards. For each of the approximately 55,000 US community water systems, concentrations of raw water constituents, treatment type, and removal efficiencies were sampled from statistical models and used to compute finished water concentrations. Modeling the effects of different regulations at the same time and using the same modeling assumptions allowed the cost‐effectiveness of alternative regulations to be compared on an equal basis. For example, this study found that the revised arsenic maximum contaminant level (MCL) is more cost‐effective than the uranium MCL at reducing cancer risk. By facilitating more direct comparison of the cost‐effectiveness of different regulations, an integrated model can help utilities prioritize their regulatory options. In addition, a better understanding of the joint effects of different regulations may help USEPA and other stakeholders to design more effective overall regulatory programs.