Loadings of PCBs and PAHs from Hamilton Harbour to Lake Ontario

Abstract

Abstract Large-volume water samples were collected from the ship canal connecting Hamilton Harbour and Lake Ontario while detailed simultaneous measurements of water speed and direction were made. The 10-day sampling period in July 1989 and a 14-day sampling period in March 1991 were considered representative of typical stratified summer and unstratified winter flow regimes. The water samples were analysed for PCBs and PAHs, which are known major organic contaminants in Hamilton Harbour. Supporting physicochemical measurements were also made. The water movement data were combined with the contaminant concentrations and the uniform channel dimensions to calculate annual loadings of 2.8 kg/ year PCBs and 37.5 kg/ year PAHs from Hamilton Harbour to Lake Ontario. These estimates were compared to other published estimates of loadings of these compounds from Hamilton Harbour and also from the atmosphere and the Niagara River. It was concluded that Hamilton Harbour is not a significant source of these compounds in comparison to the atmosphere and the Niagara River. The PAH export estimate was found to be small when compared to in situ sediment burdens of PAHs and also present day discharges to the harbour.