Data for Occurrence and Sources of Lead in Private Wells, Sturbridge, Massachusetts

This dataset contains water-quality data, quality-control data, and input and output data for geochemical models that support the findings of a study of lead in drinking water in the Sturbridge, Massachusetts, study area. These data include major and trace element data for unfiltered and filtered (dissolved) samples collected from both taps and well heads at private well sites, and quality-control data, including blank sample data and replicate sample data. The computer program PHREEQC (Parkhurst and Appelo, 2013) was used with the water-quality data and the WATEQ4F thermodynamic database (Ball and Nordstrom, 1991) to calculate aqueous and surface speciation; mineral saturation index (SI=log (IAP/K), where IAP is the ion activity product and K is the solubility constant) values; and corrosivity indicators such as the calcite saturation index (SIc) and the chloride-to-sulfate mass ratio (CSR). These calculations were used to help understand the effects of geochemical reactions on lead and related parameters in groundwater and tap water of the study area. References: Ball, J.W., Nordstrom, D.K., 1991. User's manual for WATEQ4F with revised data base: U.S. Geological Survey Open-File Report 91–183, 189 p., http://wwwbrr.cr.usgs.gov/projects/GWC_chemtherm/pubs/wq4fdoc.pdf. Parkhurst, D.L., and Appelo, C.A.J., 2013, Description of input and examples for PHREEQC version 3—A computer program for speciation, batch-reaction, one-dimensional transport, and inverse geochemical calculations: U.S. Geological Survey Techniques and Methods, book 6, chap. A43, 497 p., http://pubs.usgs.gov/tm/06/a43.