Field Data Report Lake Ontario Tributaries 2005-2006

The Lakewide Management Plan for Lake Ontario has identified six critical pollutants which contribute to lakewide beneficial use impairments due to their toxicity, persistence in the environment, and/or their ability to bioaccumulate. The six critical pollutants are polychlorinated biphenyls (PCBs), mercury, DDT, dieldrin, mirex, and dioxins. Approximately 80% of the surface water flow to Lake Ontario is from the Niagara River. A long term monitoring program conducted by Environment Canada, as a component of the Niagara River Toxics Management Plan, has provided good estimated loadings of pollutants from the Niagara River and the upstream Great Lakes. However, definitive current information regarding loadings from other U.S. tributaries to Lake Ontario had been lacking. In 2002, the U.S. Environmental Protection Agency (EPA) initiated a program to regularly monitor U.S. tributaries for the critical pollutants. Previous reports have provided program results for 2002 through 2004. This report adds changes and results from 2005 through 2006