Velco’s Toxic Cocktail Letter from Sylvia Knight It’s time to consider VELCO’s herbicides to be used at their new substation, which has an underground drain extending 100 feet into the nearby wetland. Any herbicides used in the substation will probably enter the wetland near Pringle Brook.

 Consider a toxic cocktail of imazapic, glyphosate, sulfometuron methyl, chlorsulfuron, spreading agent, drift retardant (either acrylamide- or silicone-based) and “inert” ingredients. One inert, isopropylamine, already disclosed by EPA, is known to be toxic.

Imazapic kills plants by preventing the action of an enzyme needed for building amino acids, affecting plants at very low concentrations (parts per trillion). Drift during treatments can be harmful to nearby plant communities. Because imazapic is soluble in water, remains stable both in soil and water, leaches easily from soil, and is likely to move off-site, EPA has required more testing on long-term and reproductive toxicity of imazapic to birds, fish, aquatic organisms, and non-target plants.

Glyphosate can cause severe injury to desirable plants and hinder their ability to resist disease. Combined with spreading agents, glyphosate is toxic to amphibians, especially tadpoles. Persistent in soil in colder climates, it can act as a phosphorous source and stimulate algae growth in waterways. It is toxic to soil microorganisms but can be very difficult to measure in soil or water samples.

Sulfometuron methyl and chlorsulfuron (SUs) can damage non-target plants at about 10 parts-per-trillion, concentrations not detectable in normal laboratory procedures. Persistent and mobile in soil and water, they can easily move offsite. Toxic drift during treatments or even of SU-contaminated soil dust carried off-site by wind can prevent normal seed or fruit formation in nearby plant communities without causing visible damage to the plants. Related chemically to medicines used to control insulin function in humans with diabetes, they may be able to affect hormone systems in animals and humans.

Chemical mixes have been shown to be more toxic to wildlife at lower concentrations than individual chemicals, but EPA tests only individual chemicals without other ingredients. How do you feel about the use of such herbicides in wetlands, with no regulation and no consideration of non-toxic alternatives?

Sylvia Knight Earth Community Advocate & Researcher Charlotte, VT