Effects of human-induced alteration of groundwater flow on concentrations of naturally-occurring trace elements at water-supply wells

► Human perturbation of aquifers mobilizes trace elements that can exceed human health benchmarks. ► Changes in geochemical conditions due to mixing of waters drives mobilization. ► Trace element concentrations in mixed waters can exceed those in end-member waters. ► An evaluation framework shows trace element mobilization potential and possible mitigation..