Trace metal and major ion inputs into the Olentangy River from an urban storm sewer

Trace metal clean techniques were used to sample and analyze the input of dissolved trace metals, major ions, and dissolved organic carbon (DOC) from a storm sewer along an urban highway in Columbus, OH. The outfall, draining a 3.6 ha sewershed with 100% impermeable surface area, discharges into the Olentangy River. Dissolved Pb (average concentration of 3 nM) and dissolved Zn (average concentration of 127 nM) were found to be much lower in concentration than reported in previous investigations of dissolved metals in urban stormwater runoff. Average concentrations of dissolved Cr (1 microM), Ni (0.087 microM), and Cu (0.33 microM) were similar to those reported in previous studies. The storm sewer is shown to be a significant source of V, Ni, and Zn to the river. The outfall is also a significant source of Na, NH4, Cl, and DOC. The storm sewer input is depleted in NO2 and NO3 as compared to the river, reflecting the highly agricultural land use of the watershed upstream of the sewershed. Input from the storm sewer is also depleted, as compared to the river, with respect to dissolved Mg, Sr, and U with probable sources in the limestone/shale bedrock and glacial till-derived soils in the watershed.