The Health Department's responsibility is to protect the health of Vermonters by making recommendations to the Department of Environmental Conservation regarding chemicals in drinking water. In 2016, two things triggered a change in thinking about the U.S. Fish & Wildlife Services' application for lampricide (TFM) use:
The mouth of the LaPlatte is near the intake for the Champlain Water District. The Champlain Water District is a public drinking water system, regulated by DEC, which provides drinking water for 70,000 people. If applied to the LaPlatte River, lampricide (TFM) will likely be in the water at the intake for the Champlain Water District, and could enter the public water supply.
Activated charcoal filtration works to remove this chemical from water, and is used to treat drinking water in other places in the country where TFM is applied. The Champlain Water District does not have an activated charcoal filtration system, and the U.S. Fish & Wildlife Service did not include any mitigation measures in its lampricide treatment plan.
After speaking with state and federal partners in other areas of the country, we learned that it would be unprecedented to apply TFM near a public drinking water system that does not have activated charcoal filtration to remove the chemical before it reaches the consumer.
Having recently reviewed the presence and impact of PFOA found in water supplies for Vermonters, the Health Department is carefully reviewing chemicals and adding an extra layer of scrutiny in such instances. In this case, there is no known amount of TFM that would be safe for people to ingest. This is partly due to the EPA having “no expectation that people would be exposed through consuming drinking water.” For many years, 35 parts per billion (ppb) has been considered safe, but the study that supports that level is more than 40 years old and of questionable quality.
Before making an assurance that drinking water with TFM is safe, the Health Department must review a modern, rigorously done, toxicity study. Until that time, we recommend that water containing TFM not be used for drinking, cooking, or preparing food or beverages.
The Health Department recommended that no one drink the water if TFM was present above the detection level of 3 ppb.
A new study was designed to understand more about how TFM could affect people’s health. The animal study showed that TFM did not cause any adverse health effects. Health Department scientists used this information to develop a drinking water health advisory level for TFM. The updated health advisory level for TFM is 100 ppb.