The presence of contaminants — both anthropogenic and geogenic, or naturally occurring species derived from geologic sources — in U.S. groundwater resources used for public supply was assessed by U.S. Geological Survey (USGS) researchers.

Groundwater quality was analyzed in 25 principal aquifers that account for 84% of groundwater pumped for public supply. Each site was sampled across its lateral extent using an equal-area grid, typically with 60 wells per principal aquifer. Samples were analyzed for 502 constituents, of which 374 had either a regulatory or non-regulatory human-health benchmark.

Geogenic constituents affect a larger population compared to anthropogenic constituents. Source: USGSGeogenic constituents affect a larger population compared to anthropogenic constituents. Source: USGS

The results published in ACS ES&T Water confirm that elevated concentrations (relative to the human-health benchmarks) of geogenic constituents have a larger effect on the quality of groundwater used for public supply than anthropogenic constituents. This trend is indicated by three metrics: detection frequency; prevalence (based on area); and population potentially affected.

Elevated concentrations of unregulated geogenic constituents are broadly prevalent and, on a proportional basis, potentially affect 18.5 million people using groundwater from the aquifers evaluated in this study. The researchers suggest that additional attention to unregulated constituents may be warranted.

To contact the author of this article, email shimmelstein@globalspec.com