By CRAIG MATTSON
It takes vigilance to protect Lake Michigan. New ecological problems challenge Wisconsin residents, scientists and policymakers to come up with solutions. And just as some of the Great Lake’s problems are solved, new threats make their way into its waters. The changing nature of this marine ecosystem means there is often no final solution to keeping it clean.
Since the Clean Water Act was mandated in 1972, water quality in the Great Lakes has dramatically improved. The Clean Water Act helped clean up industrial pollution, also called point source pollution. Professor Val Klump, Director of the Great Lakes Water Institute said we are still dealing with a legacy of point source pollution, but that we have come a long way since the Clean Water Act.
“Lake Erie was once declared dead,” Klump explained. In 1969, Cleveland’s Cuyahoga river, a tributary River that enters into Lake Erie literally caught on fire due to its oily surface. “With strict controls, Lake Erie improved significantly. But recently there has been a huge mutation due to algae blooms. Here, we now see warnings about swimming and drinking,” Klump said. The new threat is due to non-point source pollution.
Non-point source pollution is mainly caused by agricultural runoff containing pesticides and fertilizers. And when homeowners use these products on their lawns, rain storms often carry them into the lake.
Mount Mary College professor of chemistry Dr. Colleen Conway offered potential solutions to non-point source pollution that people can do right at home. “Don’t put fertilizer on your lawn before it rains. Don’t put extra fertilizers or pesticides on your yard. The fewer people that do pesticides, the better off we all are, because all of that stuff is running into the lake,” Conway said.
The regulation of sewer water plays a vital role in keeping runoff out of the lake. Milwaukee Metropolitan Sewer District built Milwaukee’s deep tunnel system in 1994, which improved sewage overflows after storms. This dramatically reduced overall sewer runoff in Milwaukee. In addition, the DNR monitors 29 Wisconsin storm sewer systems as well as 14 municipal and 20 industrial waste water treatment facilities.
The DNR is currently working with the Great Lakes Restoration Initiative, a project designed to help with 51 projects submitted by Wisconsin agencies and organizations. One critical goal is to reduce agricultural and nutrient runoff, soil particles from construction, and contaminated sediment from rivers into the Fox River, Green Bay, and other watersheds into the Great Lakes.
Some industries have continued to play a huge role in polluting Wisconsin’s waterways. “The lower Fox River is heavily contaminated with polychlorinated biphenyls, or PCBs, from the paper industry,” Klump said. “Some contaminants are still in the system from 20 to 30 years ago.”
Projects initiated by the DNR are designed to remedy some of these problems. Completed in 2008, 4000 pounds of sediment contaminated with PCBs was removed from the Blatz Pavilion in the Estabrook impoundment and deposited into landfills in Muskego and Belleville, MI certified to store and treat hazardous waste. Currently, the DNR is partnering with Milwaukee and the EPA to remove 100,000 cubic yards of PCB contaminated sediment from Lincoln Park and the Lincoln Park/Milwaukee River channels area.
There is yet more to Lake Michigan’s ecological health than the problem of pollution. New threats come in the form of invasive species. Zebra Mussels, first detected in the Great Lakes in 1988 pose another set of problems for researchers and policy makers to come to terms with.
Zebra Mussels live in the hulls of ocean going ships traveling through the St. Lawrence Seaway. Though Zebra mussels originate in salt water, they survive in the fresh waters of Lake Michigan. According to Professor Klump, their effect on Lake Michigan ecology is significant.
“Lake Michigan ecology has changed significantly in the last ten years,” Klump said. “The water is clear, but the food web has collapsed. The ecosystem has been disrupted by the invasion of the mussels.” The food web determines how living creatures relate to each other in the food chain.
The relationship among different forms of marine life is complex. Algae provide nutrients for the mussels. Mussels eat these algae, creating clear, clean looking water. “The rotten smell that emerges from the lake shore is a result of the algae Cladophora , which has had a huge resurgence with the incoming Zebra mussels,” Klump said. Though the water appears clear, it is not as clean as it looks.
Though Wisconsin has done a great job of cleaning up pollution from past industrial runoff, the Great Lakes need to be consistently monitored for new threats. One of the latest is an invasive species of fish called Asian Carp which comes through from the Mississippi River.
The Wisconsin DNR website describes potential effects of Asian Carp in Lake Michigan. “These invasive fish are a grave concern because they can aggressively compete with native commercial and sport fish for food and can potentially disrupt entire ecosystems.”
The effect of this invasive species on the lake, and how agencies cope with it, will form the next chapter in the story of how we protect the Great Lakes.
For more information, go to: