Pollution in Lake Michigan

Pollution in Lake Michigan

Introduction

The Great Lakes has traditionally been a center for investigation into the processes, transport, and fate of toxic atmospheric deposition. As a result there is a great deal of information about how contaminants are transported and deposited to the Lakes, where they are coming from and from what categories of sources, and how they may be re- emitted into the atmosphere from the Lakes to be deposited again in another location. Below are a few of the high- lights from the Lake Michigan Mass Balance Study and other recent research. Many of these studies point to the Chicago region as a major source area, due primarily to the fact that monitoring and modeling data are available for this region. The Chicago region should not necessarily be considered more or less of a source area than other urban industrial regions in the basin

Pollution in Lake Michigan

The Great Lakes hold 1/5 of the fresh water on Earth. The Great Lakes basin has been used as a resource for industry, agriculture, shipping, and recreation for over 200 years. As a result of eutrophication, over fishing, and the wide spread presence of toxic substances in the early 1960's, (Dams, 56) the quality of water began to deteriorate. By the 1970's the Great Lakes had become dumping sites for agricultural, industrial, and domestic wastes.

Lake Michigan is the third largest of the Great Lakes, and the fifth largest lake in the world. It is the only of the Great Lakes to be entirely in the United States. It allows only small amounts of water to flow out through the straits between Lakes Michigan and Huron. Because it takes so long to "flush" Lake Michigan (it takes 100 years for a complete change of water), water pollution is a serious concern. (Dams, 56)

Lake Michigan also has the largest sport fishery on the Great Lakes. Therefore it is especially threatening because pollution has been shown to interfere with reproduction in birds and lake trout. It also has been implicated in the development of neoplastic tumors in bottom-dwelling fish. High concentrations of PCBs have led to some advisories restricting the consumption of certain fish.

People can be exposed to Great Lakes pollutants through inhalation of air, ingestion of water, food or contaminated soil, and dermal contact with water or airborne particulates. 80-90% of human exposure is a result of ingestion through the food chain. 5-10% is from air, and less than 1% is from water. Studies of people living in Great Lakes states demonstrate increased tissue levels of toxic substances that may be associated with or result in reproductive, develop- mental, behavioral, neurological, endocrinological, and immunological effects. People are at greater risk along Lake Michigan because more people are drawn to it because it has the largest lakeshore sand dunes in the world along with many beaches, coastal state parks and national lakeshores.

Lake Michigan supports a wealth of plant and animal life (biological diversity) found no- where else in the ...