Suspended Solids, Trace Metal and PAH Concentrations and Loadings from Coal Pile Runoff to Hamilton Harbour, Ontario

The Kenilworth boatslip has been identified as a “hotspot” within the Hamilton Harbour Area of Concern because of highly contaminated bottom sediments. There are a variety of sources potentially contributing to this sediment contamination, including runoff from industrial coal piles. The objective of this study was to assess the contaminant characteristics associated with coal pile runoff and identify potential impacts that the runoff might have on sediment quality. Flow-proportioned samples of the coal pile runoff were collected from June through October, 1996 and analyzed for total suspended solids, trace metals, and PAHs. Loadings for selected metals and PAHs were determined using a volumetric approach that considered mean contaminant concentrations and measured or modeled flow volumes. The suspended solids and total trace metal concentrations (Al, Fe, Mn, V, Cd, Cr, Cu, Pb, Zn) often exceeded Canadian Water Quality Guidelines for the Protection of Aquatic Life. Concentrations of fluoranthene, phenanthrene, pyrene, and chrysene exceeded the provincial “Severe Effect Level” for sediment, although the bioavailability of these PAHs should be examined more thoroughly. In general, suspended solids concentration and coal pile volume were significantly correlated with the concentrations of trace metals in the coal pile runoff, while hydrometeorologic variables such as rainfall intensity, rainfall depth, and runoff volume were weakly correlated with metals concentrations. The ratios of various PAHs to naphthalene suggested that coal pile runoff could be an important contributing source to bed sediment contamination. Given the concentrations and loadings of solids, metals, and PAHs and the relatively low volume of runoff, it would be prudent to treat the coal pile discharge as a remedial action for the harbor.