Aquatic Weeds Overwhelming Nation’s Lakes

Published August 1, 2005

On June 22, Josafat Nava Gallardo, 19, of Brooklyn Park, Minnesota, sought to retrieve a soccer ball that had gone into Lake Minnetonka. Gallardo never retrieved that ball, as he drowned in the waters of the lake after becoming entangled in the overgrown milfoil, an aquatic weed. His body was recovered two days later.

While the consequences of overgrown aquatic weeds are often less dramatic, those weeds are preventing the safe recreational use of many lakes in the United States. They are often invasive species, not native to America.

Milfoil, sometimes known as Eurasian Watermilfoil, has grown significantly in Lake Minnetonka. According to Minneapolis television station WCCO, the lake is so thick with milfoil that experienced divers find the lake frightening.

Some communities have sought to control aquatic weeds such as milfoil through the use of herbicides. Environmental groups, however, are strenuously opposing those plans.

Wisconsin Residents Favor Herbicide

Many residents around Lake Pewaukee, about 25 miles west of Milwaukee, Wisconsin, have advocated the use of herbicides to control milfoil in the lake so they can more safely swim and boat there.

Lake property owners have pooled their resources to apply herbicides in their portion of the lake, and they have asked the City of Pewaukee to use the herbicide generally known as 2,4-D on a larger portion of the lake.

Commenting on the use of 2,4-D in the June 7 Milwaukee Journal Sentinel, Bob Giblin, president of the Pewaukee Lake Improvement Association, said, “It’s exactly what you use to control dandelions in your yard without killing the grass.”

Scientists, EU Confirm Safety

The herbicide 2,4-D is one of the most widely used in the world and is used on both land and in water. It has been used commercially since 1946 and is approved by the European Union. Many scientific studies have cited its safe usage.

Based on that information, Giblin reports 70 percent of lake property owners who completed a recent survey believe herbicides should be used to control the aquatic weeds in the lake.

Nevertheless, on June 20, the Common Council for Pewaukee chose to amend the Pewaukee Lake Management Plan to allow more mechanical means to cut the aquatic weeds, refusing to approve the use of herbicides.

Massachusetts Lake Unsafe

Like the Pewaukee dwellers, residents around Morses Lake in Wellesley, Massachusetts want their lake to be cleared of overgrown weeds.

According to the June 2 Boston Globe, many local residents remember the lake as once being filled with sailboats and other recreational users. Sunday sailboat regattas were held on the lake during the 1960s and 1970s.

Today, sailboats are almost never seen there because the aquatic weeds are so thick it is not safe to operate boats.

The Morses Pond Ad Hoc Committee has advocated the use of fluridone to control the weeds. They say the herbicide is safe, effective, and much cheaper than alternatives.

Ken Wagner, Ph.D., an environmental specialist hired by Wellesley, was quoted in the Boston Globe stating that the cost of fluridone would be about $300,000 over a 20-year period. Other options, such as dredging, mowing, or hand pulling, would cost between $1.2 and $5 million.

Enviro Group Stepped In

The Wellesley Cancer Prevention Project, led by Sara Frost Azzam, opposes the use of any herbicide in Morses Pond because the pond also supplies drinking water.

In the draft recommendations prepared by Wagner for the City of Wellesley, he defended the safety of fluridone, noting the amount to be used in the lake would be only eight parts per billion, less than half the amount the federal government permits in drinking water.

Wellesley will continue to study weed treatment options before making a final decision.

Michael Coulter ([email protected]) is associate professor of political science and humanities at Pennsylvania’s Grove City College.