Aerial Spraying for Mosquitos and Weston's Water
We have been receiving some calls of concern stemming from a recent article in the Boston Globe regarding contaminants found in drinking water caused from the aerial application of pesticides.
In summary, the Commonwealth can decide to apply pesticides via an aerial means without an approval process by the communities involved if a Public Health Emergency warrants this course of action. This pesticide application process is a result of new legislation enacted last year after the spring 2019 Eastern Equine Encephalitis (EEE) outbreak and provides the state an easier means to take action in the case of another EEE outbreak. This legislation also gave communities the ability to request to be exempted from the pesticide applications, which would be reviewed by the state. The request could be approved or denied based on past risk history. The opt-out request requires the municipality to provide a detailed alternative management plan for mosquito control.
To clarify the process, the State Reclamation and Mosquito Control Board (SRMCB) oversees each of the state's Mosquito Control Districts (MCD). The Control Board oversees the state's emergency aerial (airplane) spraying during EEE emergencies; however, the MCD activities and state aerial sprayings are completely separated.
Further, the article cited the PFAS compounds of concern do not exist in the pesticide itself but leeched into the product from a coating used in the packaging. PFAS are a class of human-made chemicals typically associated with the manufacturing of non-stick coatings, water-proofing, and stain-proofing treatments. The aerial mosquito control product, Anvil 10+10, that was used during the 2019 aerial spraying conducted by the state Control Board was found to have PFAS in parts per trillion. The Environmental Protection Agency (EPA) and pesticide company have since resolved the container issue, so the PFAS are no longer in the pesticide product.
Two very important things to note:
- Weston's Mosquito Control District is the East Middlesex Mosquito Control Project (EMMCP)
- Weston receives its water from the Massachusetts Water Resources Authority (MWRA)
East Middlesex Mosquito Control Project
An aerial application of mosquito control is applied in the spring by the East Middlesex Mosquito Control Project (EMMCP) to wetland areas in an effort to prevent the mosquito larva hatching and development. This year, it was supposed to have occurred in April but due to various weather-related delays, the application did not take place as the effective window for the application was missed. The product applied by the EMMCP does not contain PFAS compounds. It is a different product from what was used by the state. This product is targeted to the DNA of mosquito larvae and does not harm other insects or birds.
The EMMCP also performs truck mounted and backpack sprayings in wetland areas in Weston when the tapping locations indicate high populations of a particular vector populations and/or when a disease carrying mosquito is found at the trapping site.
Massachusetts Water Resources Authority
Weston's water is thoroughly tested by the MWRA. The watersheds and reservoirs are well-protected. The Massachusetts Department of Environmental Protection (MassDEP) set a standard of PFAS contamination to 20 parts per trillion on October 2, 2020. The new testing requirements went into effect in January 2021 and MWRA began quarterly testing as prescribed under the new standard. However, MWRA has been testing for the six regulated PFAS, as well as a dozen other PFAS compounds, using extremely sensitive testing methods since 2019. The MWRA easily met the January 2021 standard and no more than trace amounts were detected, too low to be quantified. The sum of the six regulated PFAS compounds was zero, below the new MassDEP standard of 20 parts per trillion. The results are posted to the MWRA website.
Opting Out of State Spraying
Weston's Department of Public Works, Board of Health, Conservation Commission, and the Select Board will be discussing its mosquito management plan and options to pursue an opt-out request with the state for calendar year 2022. It is too late for Weston to opt-out for 2021. An Act to Mitigate Arbovirus in the Commonwealth is the legislation that created the opt-out procedure, and it only allows municipalities to opt out for 2021 or 2022. EEE outbreaks historically occur in 2-4 year cycles and typically becomes prevalent later in the summer to early fall. 2019 was the first year of this cycle and 2022 will be the fourth.