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Relation between road-salt application and increasing radium concentrations in a low-pH aquifer, southern New Jersey

November 18, 2021

The Kirkwood–Cohansey aquifer in southern New Jersey is an important source of drinking-water supplies, but the availability of the resource is limited in some areas by high concentrations of radium, a potential carcinogen at elevated concentrations. Radium (226Ra plus 228Ra) concentrations from a network of 25 drinking-water wells showed a statistically significant increase over a decadal time scale (p < 0.05), with a median increase of 0.35 picocuries per liter. Increases in Ra are correlated with road-salt application rates, and we hypothesize that the correlation is causal. Geochemical processes associated with road-salt applications that can mobilize Ra into solution include competition by excess sodium for sorption sites and formation of chloride complexes (RaCl+ and RaCl2). The largest increases in Ra were in groundwater with low pH (≤5), which is an indirect surrogate for low cation-sorption capacity. Correlations with other potential anthropogenic causes for the increase in Ra were not observed, further suggesting a road-salt effect. Given the significant increase in Ra concentrations in this drinking-water source, the known carcinogenic risks from Ra, the direct link to road-salt application, and the likelihood for continued increases, additional monitoring is necessary in areas with similar hydrogeologic and geochemical settings.

Citation Information

Publication Year 2021
Title Relation between road-salt application and increasing radium concentrations in a low-pH aquifer, southern New Jersey
DOI 10.1021/acsestwater.1c00307
Authors Bruce D. Lindsey, Charles A. Cravotta, Zoltan Szabo, Kenneth Belitz, Paul Stackelberg
Publication Type Article
Publication Subtype Journal Article
Series Title Environmental Science and Technology Water
Series Number
Index ID 70227798
Record Source USGS Publications Warehouse
USGS Organization National Water Quality Assessment Program