PFAS found in mosquito spray used in US states

Communities across the US may be polluted with toxic and persistent per- and polyfluoroalkyl substances (PFAS) from pesticides sprayed to control mosquitoes, new data suggest.

Separate testing by the advocacy group Public Employees for Environmental Responsibility (PEER) and the Massachusetts Department of Environmental Protection found PFAS in Anvil 10+10, a synthetic pyrethroid insecticide. Mosquito control programs in a number of states, including Massachusetts, spray this product from trucks and planes, PEER says.

The two analyses, each of which could detect the same 36 PFAS, found that Anvil 10+10 contained perfluorooctanoic acid (PFOA); hexafluoropropylene oxide dimer acid, a product of hydrolysis of GenX, Chemours’s substitute for PFOA; perfluorobutanoic acid; and perfluorohexanoic acid, among others.

“In Massachusetts, communities are struggling to remove PFAS from their drinking water supplies while at the same time we may be showering them with PFAS from the skies and roads,” says Kyla Bennett, science policy advisor for PEER.

Clarke Mosquito Control Products, which formulates Anvil 10+10, does not add PFAS to its products, a spokesperson for the Illinois company tells C&EN. Clarke checked its entire supply chain and found that PFAS were neither used as raw materials nor added to the ingredients in this product, the spokesperson adds. The US Environmental Protection Agency says in a statement provided to C&EN that Anvil 10+10’s pesticide registration does not include PFAS as ingredients.

However, Bennett points out, the EPA has approved a number of PFAS for use as so-called inert ingredients in pesticides. Companies can claim the identity of these inert ingredients as trade secrets.

Many nonpolymeric PFAS are useful surfactants and antifoaming agents and can extend the shelf life of pesticide active ingredients, Bennett says. “We do not know how many insecticides, herbicides, or even disinfectants contain PFAS,” she adds.

PEER informed the EPA about the testing results in late November. The agency, which is working to reduce the public’s exposure to PFAS, says it is testing additional samples of Anvil 10+10 and is developing an analytical method to detect PFAS in pesticide products.