Cost of Our Choices in Methods of Manipulating Lake Ecosystems

Lake management has not escaped the debate over chemical use. Small-scale chemical treatment of aquatic plants is common in Wisconsin and thee seems to be a growing demand for larger scale applications. In meetings across the state, citizens concerned with large-scale chemical applications are gathering to express their apprehension.
The widespread use of chemicals that serve all parts of our society began in earnest with the close of WWII. The payback for chemical use seemed to far outweigh any side effects. However, grim discoveries have come to light making more and more people suspicious, afraid and nervous about accepting the tempting promises over the environmental risks of chemical use.
The main way to chemically control aquatic plants on Wisconsin lakes through the 1950’s and 60’s was the use of sodium arsenite (which contains inorganic arsenic that can be fatal if swallowed) with over 2 million pounds used in 167 Wisconsin lakes. Another common treatment was copper sulphate. An accumulation of copper in bottom sediments can adversely affect important food chain organisms. Between 1959 and 1969, over 1.5 million pounds of copper sulfate were used in our lakes to kill snails thought to cause swimmers’ itch. With current knowledge, the idea of applying some of the chemicals used in the 50s and 60s as treatments would be unthinkable. Yet, back in the day it was thought of as a state-of-the-art practice.
Each year in Wisconsin there is growing pressure to do large and even whole-lake treatments to limit the growth of nuisance plants such as Eurasian water milfoil. We need to weigh the benefits and cost of our choices in methods of manipulating lake ecosystems to make sure the decisions we make today leave options open for those that will care for our lakes in the future.

—excerpt from Robert Korth, UW-Ex Lakes Specialist as published in ‘Lake Tides’