Drivers of Spatiotemporal Variability in Drinking Water Quality in the United States

Abstract

Approximately 10% of community water systems in the United States experience a health-based violation of drinking water quality; however, recently allocated funds for improving United States water infrastructure ($50 billion) provide an opportunity to address these issues. The objective of this study was to examine environmental, operational, and sociodemographic drivers of spatiotemporal variability in drinking water quality violations using geospatial analysis and data analytics. Random forest modeling was used to evaluate drivers of these violations, including environmental (e.g., landcover, climate, geology), operational (e.g., water source, system size), and sociodemographic (social vulnerability, rurality) drivers. Results of random forest modeling show that drivers of violations vary by violation type. For example, arsenic and radionuclide violations are found mostly in the Southwest and Southcentral United States related to semiarid climate, whereas disinfection byproduct rule violations are found primarily in Southcentral United States related to system operations. Health-based violations are found primarily in small systems in rural and suburban settings. Understanding the drivers of water quality violations can help develop optimal approaches for addressing these issues to increase compliance in community water systems, particularly small systems in rural areas across the United States.

Long-Term Continuous Test of H2-Induced Denitrification Catalyzed by Palladium Nanoparticles in a Biofilm Matrix

“…In stage 1, we fed both reactors with the influent NO 3 − at 14 mg-N/L, a concentration greater than the MCL. 7 The H 2 supply was maintained at 10 psig (1.68 atm absolute pressure) in the first substage. Then, the H 2 pressure was lowered to 5 psig (0.84 atm) and then gradually increased to 10 psig in the subsequent substages.…”

“…The HRT was 12.4 ± 1.0 h throughout the experiment. In stage 1, we fed both reactors with the influent NO 3 – at 14 mg-N/L, a concentration greater than the MCL . The H 2 supply was maintained at 10 psig (1.68 atm absolute pressure) in the first substage.…”

“…Nitrate (NO 3 – ), a ubiquitous water pollutant in surface water and groundwater worldwide, , poses substantial threats to public and ecological health. Excessive NO 3 – exposure induces methemoglobinemia in infants and digestive tract cancer. , A high concentration of NO 3 – in surface water causes eutrophication and toxic algal blooms. , The U.S. Environmental Protection Agency (EPA) regulates NO 3 – at a maximum contaminant level (MCL) of 10 mg of N/L for drinking water, and standards for wastewater discharge are often much lower …”

Quality of Groundwater Used for Public Supply in the Continental United States: A Comprehensive Assessment

“…Treatment might or might not change the concentrations of a constituent. Some constituents, such as lead and disinfection byproducts, can be introduced after groundwater is pumped from a well. Other sources could include surface water and/or groundwater from other wells.…”

“…This paper complements previously published work that relies on regulatory data for finished water as compiled by the USEPA. Several papers have reported on water quality violations reported to the Safe Drinking Water Information System, as required by the SDWA: coliform, nitrate, and any type of violation . Other papers have reported on the concentrations of arsenic as compiled by the USEPA for its third Six-Year Review. , This paper evaluates untreated groundwater rather than finished water, includes constituents not compiled by the USEPA (those with nonregulatory HHBs and geochemical indicators), and evaluates water quality in the context of principal aquifers.…”