Most trace metals measured as part of environmental monitoring efforts are naturally occurring, and many are essential as nutrients, but all metals can be toxic at high concentrations. Elevated sediment concentrations can be indicators of metal contamination released into the environment by human activity. Sources such as wastewater effluent, atmospheric deposition, urban runoff, and copper-based products all contribute to trace metal concentrations in sediments.
Metal trends were identified for cadmium (Cd), copper (Cu), lead (Pb), nickel (Ni) and zinc (Zn) at 90 sites between 2008 and 2022. Most sites show stable or no trends. Increasing trends for Cd at 10%, Cu at 24%, Pb at 19%, Ni at 21% and Zn at 19% of sites were observed.
Statewide, Cd and Pb are decreasing, and urban land use relationships are identified for Cu, Pb, Ni and Zn. Pb and Zn are also significantly related to agricultural land use.
Metal trends were identified for cadmium (Cd), copper (Cu), lead (Pb), nickel (Ni) and zinc (Zn) at 90 sites between 2008 and 2022. Most sites show stable or no trends. Increasing trends for Cd at 10%, Cu at 24%, Pb at 19%, Ni at 21% and Zn at 19% of sites were observed.
Statewide, Cd and Pb are decreasing, and urban land use relationships are identified for Cu, Pb, Ni and Zn. Pb and Zn are also significantly related to agricultural land use.
