FOREST SOIL AND RIVER WATER CU, NI, PB, AND ZN ACROSS SEVEN WATERSHEDS IN EASTERN CONNECTICUT – INSIGHTS ON SEQUESTRATION AND EXPORT

Sequestration and transport of copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn) are important due to its potential impacts on terrestrial and aquatic ecosystems and its sourcing from human activities. This is of particular importance in the Thames River Watershed of eastern Connecticut due to its abundant urban areas, historical pollution, and export to Long Island Sound. Forest soils in upland and riparian positions as well as adjacent to urban, agricultural, and forests were sampled across seven watersheds to investigate sequestration of metals. Further, river water samples from Feb 2019 to Jan 2020 were collected at least monthly. Upland, forest soils had lower metal concentrations than urban, riparian soils for Ni and Pb. Forest soil Cu and Zn concentrations were comparable between upland and riparian soils as well as forest, developed, and agricultural adjacent forest soils. River water sample concentrations were generally comparable across the watersheds. To account for differences river size and discharge, concentrations and discharge rates were used to estimate annual export rates. The larger Quinebaug and Shetucket watersheds had the highest annual export rates for Cu, Ni, Pb, and Zn. When normalized per square kilometer of watershed area, the Quinebaug watershed still had the highest Cu, Ni, Pb, and Zn exports, most likely due to the higher urban areas than the other watersheds. This agrees with the urban forest soil metal concentrations. However the normalized annual export results show some of the smaller, less urbanized watersheds had high exports of Cu and Ni. This could be due to modern point source pollution or export of historical pollution.