Massachusetts groundwater and streamwaters range from crystal clear and pristine quality to being heavily contaminated from natural and historical industrial activities. These contaminants range from organic compounds like DDT, PFAS, and Trichloroethane. However, there are many rivers with historical trace metal pollution.

In central and eastern Massachusetts, groundwater have elevated concentrations of arsenic (As), copper (Cu), and lead (Pb). This has been commonly linked to metamorphic rocks throughout the region. The interesting part is that groundwater can have very high As, Cu, and Pb concentrations but we have little understanding how this relates to stream waters and their implications for fish and wildlife. In this study, we examined streamwaters across watersheds with different bedrock (sulfidic schists) and used rock samples to examine trace element concentrations and their effects. 

As a brief summary, the rocks have elevated concentrations of As and Pb but the weathering of sulfidic schists under oxic conditions produces iron oxides that rapidly adsorb and remove them from the water. Thus, near surface weathering of sulfidic schists lock up and sequester the As and Pb before it can reach rivers.

This was a team effort with collaborations form Dr. Elyse Clark at Fitchburg State University, UMass ’21 Stephanie Thrasher, and UMass PhD Brian Saccardi

Richardson et al 2023 Sulfidic schist release of As, Cu, and Pb lab and 11 watersheds central MA’