What are the main pollutants in the Great Lakes?
There are still ‘legacy pollutants’ such as polychlorinated biphenyls (PCBs) and DDT coming from atmospheric deposition as well as phosphorus and nitrogen from agriculture and sewage. However, the new problem is with endocrine disrupters. We know little about where they’re coming from but we know they’re causing oestrogenic effects. At present, they are impacting fish and birdlife but we are not sure if they are affecting people who are drinking the water. What is the greatest threat to the Great Lakes? In addition to the chemicals, biologically, there are close to 200 invasive species and a new one is added every eight months. The impact on food webs and ecology could be enormous. However, a dominant factor is the physical threat of global climate change. It affects how chemicals behave in the environment and it drives change in an ecosystem too. Everything is interrelated. Which species make good biomonitors in the Great Lakes? A coho salmon lives for three years and grows to one met
