Heavy Metal Contamination in the Mahoning River, Ohio

Mahoning River, historically one of the most contaminated rivers in the US, contains heavy metals above the US Environmental Protection Agency's aquatic criteria. This study identifies the contamination levels, spatial patterns, and bioavailability of heavy metals (As, Ba, Fe, Pb, Ni, Zn) in the sediment of the lower Mahoning River. The contamination factor indicated that heavy metals in sediments were moderately to highly polluted (3–15). Inverse distance weighting in sediments illustrated decreasing concentrations towards downstream for Ni, while increasing concentrations towards downstream for As, Ba, Fe, Pb, and Zn in sediment. The inverse distance weighting patterns may be associated with land use, as the river traverses the agricultural region upstream, the urbanized region downstream, and mixed-land areas in the last stretch. Speciation analysis revealed heavy metals in water and sediments were in divalent forms (HM2+), except for Pb (PbOH+, PbCO3), indicating high bioavailability and potential plant uptake in the aquatic environment.