Crystal Ridgill-Elliott, 1998, Distribution of heavy metals in the clay-sized fraction of sediments from the Cuyahoga River Basin, Ohio.

ABSTRACT

A previous study conducted by the Ohio Environmental Protection Agency (OEPA), 1991, found less heavy metal contamination within bottom sediments downstream of the Akron municipal area than was anticipated. It concluded that faster current and coarser gained sediment textures could have been contributing factors. In this study, 20 sediment samples were collected, fractioned to clay-size, and analyzed for heavy metal concentration by inductively coupled plasma and atomic absorption spectroscopy. Results were compared with data from an OEPA study conducted in 1991 (OEPA 1992), then grouped into a recently developed classification scheme. Results indicated that the middle regionšs average arsenic, cadmium, cobalt, copper, nickel, and zinc concentrations in bottom sediments were higher than what the OEPA observed in 1991. Average concentrations of cadmium and arsenic were extremely elevated and highly elevated respectively, throughout the upper, middle, and lower basin. When individual sites were observed, higher concentrations of heavy metals were recovered in sediments from point sources, than was indicated by previous studies. In the Upper Basin at Tare Creek the concentrations of Cd, Co, Cr, Cu, and Zn were elevated. Below the Akron wastewater treatment plant (WWTP), copper and zinc in river sediments increased to extreme concentrations. Elevated concentrations of As, Cd, Co, Cr, Cu, Ni, V, and Zn were recorded downstream from the Southerly wastewater treatment facility. The next site downstream appeared slightly higher in concentration for each metal, suggesting a possibility of contaminated sediments migrating downstream. Cadmium concentrations in water were above the water quality criteria within the entire river basin and peaked below Fishcreek, Akron, and Southerly WWTPs. Copper was above the water quality criteria at three particular sites, two of which were Akron and Southerly WWTPs. Total dissolved solids increased downstream within the Cuyahoga Riveršs water. The Piper plot concluded that the chemical composition of water in the extreme upper region began as a mixed cation, bicarbonate-rich water, became a calcium-rich, bicarbonate-rich water until reaching the Fish Creek tributary. The middle region shifted to a mixed, cation-anion, with more uniformity after the Yellow Creek tributary. The lower region remained a mixed cation-anion water, trending towards an alkali-chloride.