Harvesting vs. use of aquatic herbicides for weed control in Connecticut lakes

According to sources in the Hartford Courant and Republican-American newspapers, a number of Connecticut towns, including Winsted and Winchester, have turned to increased use of aquatic herbicides to control milfoil and other nuisance waterweeds in Connecticut ponds, lakes and even reservoirs for public water supply.

This trend is tempting given the comparative ease of application of chemical herbicides and their unquestioned seasonal effectiveness. Still, one must credit the town of Lakeville and the Lake Wononscopomuc Association for their deliberation, care and caution in addressing this problem. They continue to employ conventional waterweed harvesters in lieu of chemicals. Twin Lakes may be a different situation.

The costs of harvesting and herbiciding are fairly comparable. Both are successful, at least seasonally, that is, until the next season when it has to be done all over again. The regulatory hurdles for chemical use in Connecticut are a pain in the neck, but the convenience of application factor certainly would favor chemicals. Still, the town of Lakeville and the Wononscopomuc Association have chosen to exercise caution.

The World Health Organization is still struggling alongside local communities and governments of Vietnam, Cambodia and Laos to deal with the mortal and lasting disfiguring effects of Agent Orange sprayed and dropped by bombs during the Vietnam War (1965–1975) in order intentionally to defoliate tens of thousands of acres of forest, and inadvertently to poison farmlands of ordinary persons who had no role in the war whatsoever. 

We had been told that Agent Orange, being a herbicide and not a pesticide, is not harmful to humans, and in any event it degrades rapidly in the environment. We learned otherwise.

With this experience, WHO prefers to err on the side of caution. WHO has long warned of the risks of misuse or excessive use of Roundup and other herbicides, especially those containing Glyphosate, which is linked to lymphoma. 

The risk level of these herbicides is nothing like Agent Orange defoliant, or we hope not. The common aquatic herbicide Sonar, containing Fluridone, has not been listed by WHO as carcinogenic, but the effect on amphibians has not been determined. To date WHO has not (yet) determined how much risk is presented by the other common aquatic herbicide, Reward.

We do have this cautionary information: The active ingredient in Reward is a chemical called diquat dibromide. According to recent studies at Cornell University in Ithaca, N.Y.: “Concentrated solutions of diquat bromide may cause severe irritation of the mouth, throat, esophagus and stomach, followed by nausea, vomiting, diarrhea, severe drying out of bodily tissues, gastrointestinal discomfort, chest pain, kidney failure and toxic liver damage.”

The Cornell studies also suggest that the herbicide “may cause infertility in males.” You may consider this a plus or a minus. 

The effects vary widely among different species of fish, amphibians, reptiles, birds and mammals. For obvious ethical reasons, we cannot directly test suspected toxic chemicals on humans. Still, the Cornell studies conclude: “Very large doses of the Reward herbicide can result in convulsions and tremors …  and may be fatal to humans.” Of course, all this depends on: (a) exposure dosage; (b) persistence in the environment; and (c) cumulative effects on humans over time. 

We don’t yet know the full scientific facts. The jury is still out. But why risk the lives, health and well-being of our children and grandchildren before we find out? Let’s not have to learn the hard way. 

If any aquatic herbicide is used, it should be at the lowest possible dose in accordance with EPA guidelines. (This assumes the EPA and its guidelines continue to exist.)

Conclusion: I would commend the citizens of Lakeville and members of the Lake Wononscopomuc Association for their rational caution in dealing with this complex problem. They are a model for the rest of the state, and Connecticut could be a leadership model to improve the safety and quality of water across the nation. 

Anthony Piel is a former director and general legal counsel of the World Health Organization.