Relation between Road-Salt Application and Increasing Radium Concentrations in a Low-pH Aquifer, Southern New Jersey

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