“New Jersey has many naturally occurring arsenic sources, which can elevate the arsenic concentration in groundwater,” said Subhasis Giri, an assistant research professor in the Department of Ecology, Evolution and Natural Resources and lead author of the study published in the journal Science of the Total Environment. “Our work contributes to the understanding of this human health risk by revealing the sources of arsenic concentration in private drinking water wells, which will in turn help with mitigation.” To identify arsenic hotspots in three countries in west-central New Jersey (Hunterdon, Somerset and Morris), Giri and colleagues at Columbia University and the New Jersey Institute of Technology developed a computer model that uses machine learning to predict the likelihood that a private well is contaminated with unsafe arsenic levels.