REFINING THE POLLUTION HISTORY OF THE FORMER MUNROE FALLS DAM IMPOUNDMENT, CUYAHOGA RIVER, OHIO

The Munroe Falls Dam was first built on the Cuyahoga River, Ohio in 1817. The dam created a low-velocity impoundment that trapped the river’s sediment load and led to poor water quality. In 2005 the dam was removed in order to improve water quality and ecosystem health. Prior to the dam’s removal the impoundment sediment was cored and measured by Atomic Absorption Spectrophotometer (AAS) to characterize heavy metal concentration. This present study remeasured the cores by X-ray Fluorescence (XRF) to characterize more elements than had been measured by AAS in order to provide additional details of the pollution history. The prior study had identified a buried oily layer, having elevated Cu, Pb, Cr, and Zn concentrations and ²¹⁰Pb-dated to the time of the Great Flood of 1913. This contaminated layer was likely sourced from the inundated Erie Shops railroad repair facility located upstream in Kent, Ohio. The new XRF results show elevated Cd, Fe, and S in the oily layer. The elevated Cd and Cr are likely due to their use in electroplating train components. The elevated Fe concentration is likely due to increased metal particles washed in from the Erie Shops site. The elevated S concentration is likely due to the oil in the flood layer and thus the sulfur profiles provide an additional means of identifying the oily flood layer throughout the dam impoundment. Because the XRF method is more rapid and inexpensive than the AAS method, a greater number of samples were measured, thus allowing the spatial extent of the 1913 flood layer to be better characterized.