What are the problems with airborne toxic chemicals in the Great Lakes?
After the initial concern over toxic chemicals being discharged or leaking into the lakes, scientists began to realize that pollutants transported hundreds of miles through the air were also degrading the Great Lakes. As early as 1966 Canada and the United States asked the International Joint Commission to monitor air quality and alert them to problems. The IJC set up an International Air Quality Advisory Board to provide advice on transboundary air pollutants. Their first task was to define the airshed of each country by analyzing the potential of air pollutants from one country to have an impact on the other. In the late 1970s scientists were surprised to discover that lakes on Isle Royale, a remote wilderness island in Lake Superior, were contaminated with PCBs and toxaphene. A few weeks after a toxaphene was sprayed on cotton crops in the southern United States, it could be detected in fish in these lakes. Because the only possible source of these contaminants was the air, this dis
