Assessing public exposure to silver-contaminated groundwater from lead-free solder: an upper bound, risk-based approach

The paper summarizes the results of a study to assess the potential human health risk associated with exposure to silver-contaminated groundwater from lead-free solder leachate. The specific alloy investigated is 96.3Sn/3.2Ag/0.7Cu. Silver transport in the groundwater is modeled using a one-dimensional advection-dispersion equation, and worst-case values for all system parameters have been chosen to provide a preliminary upper bound on potential human health risk. Worst-case assumptions include high infiltration and leakage rates, high leachate silver concentration and a short distance to nearby drinking wells. Results show that in the worst-case scenario, silver concentrations may exceed drinking water standards at nearby wells after roughly 100 years. When more typical system parameters are employed, results show that silver concentrations at nearby wells may not ever exceed drinking water standards. This study therefore provides insight into the potential magnitude of human health risks associated with lead-free solder leachates. More detailed analyses are recommended to quantify potential health risks for specific populations and site conditions.