The EPA Office of Pesticide Programs (OPP) regularly shares updates via this link (you can also sign up for updates). Over the last three months, the OPP tackled multiple issues, from making certain pesticide review decisions to developing new guidelines and testing methods. Below, I have highlighted three issues that I found to be particularly interesting.
PFAS has been found in pesticides
PFAS are fluorinated compounds that have been linked to several health effects. They are found in multiple places, including drinking water where the lifetime health advisory level (i.e., maximum concentration considered safe over a lifetime) is 0.004 to 0.02 parts per trillion. To learn more about PFAS, check out this post where I had covered it in greater detail.
Currently, there is no uniform definition as to what compounds constitute PFAS. While the EPA recently broadened its definition of PFAS, it is unclear if some fluorinated pesticide active ingredients fall under this category. Regardless, PFAS was recently detected in some non-fluorinated pesticides. Where did it come from?
Pesticides constitute of active ingredients, that undergo extensive testing under FIFRA, and inert ingredients, that are regulated under TSCA. The EPA has a list of acceptable inert ingredients that have undergone screening-level assessments. The EPA recently removed 12 chemicals identified as PFAS from this list but however said these chemicals were not being used in registered pesticide products. So if the PFAS in the pesticides did not come from the active or inert ingredients, where did it come from?
The EPA’s investigation found that PFAS could leach from the walls of certain fluorinated HDPE (high-density polyethylene) containers that house pesticides. Basically, PFAS from the inner walls of the containers can readily leach into formulated liquid pesticides — greater leaching was seen for pesticides formulated in organic solvents (like methanol) vs. pesticides formulated in water-based solvents. Continuous leaching of PFAS is expected over time. However, it is unclear if all the PFAS detected in the pesticides were from HDPE leaching.
Treated seeds will continue being considered as treated articles
Certain compounds, while associated with pesticides, are not fully regulated under FIFRA. These include approved inert ingredients (as discussed above), minimum risk pesticides, pheromones, and treated articles. Treated articles contain pesticides, typically as a coating. Think of shower curtains treated with fungicides or preservatives applied on wood. In agriculture, seeds coated with pesticides are the most commonly used treated articles. The EPA does not register the treated seed but registers the pesticides applied on it.
In 2017, the Center for Food Safety filed a petition asking the EPA to reinterpret or amend the treated article exemption so that it does not apply to treated seeds. They asked the EPA to properly regulate pesticide-treated seeds (i.e., enforce registration and labeling requirements) as they are deployed over millions of acres and pose a risk to non-target organisms. The petitioners focused on neonicotinoid-treated seeds as they have systemic properties. The EPA responded by saying that it fully assesses the use of the treating pesticide and the treated seed and their impacts to human health and the environment. Also, the treated seeds meet the regulatory conditions for the treated article exemption, i.e., the treating pesticide is registered for use as a seed treatment for the specified crop, the pesticide label informs the distribution, sale, and use of the treating pesticide and the treated seed, and the claims made by the treated seed are limited to the protection of the seed and what the seed becomes. Therefore, the EPA decided not to exclude treated seeds from the treated article exemption.
The EPA however agreed with the Center of Food Safety on the importance of clearly communicating labeling instructions to users of treated seeds. The EPA has begun reviewing labels of pesticides registered for seed treatment to ensure they provide complete and relevant instructions for the distribution, sale, and use of the treating pesticide and the treated seed. Additionally, the EPA said they will seek more information on whether the treated seeds are being distributed, sold, and used in accordance with the label. In case of violations, the EPA will either enforce the law (typically through punitive measures), modify pesticide labels to clarify language or reduce use, or issue a rule to regulate treated seeds in a manner consistent with labeling instructions.
*In the original version of the article, insect repellent clothing was described as an example of treated article that does not require FIFRA registration. This is incorrect: since the pesticide on the cloth is intended to protect the wearer and not the clothing, it must undergo FIFRA registration (source: Label Review Manual).
Chitosan is now a minimum risk pesticide
In the U.S., all pesticides have to be registered under FIFRA. However, certain pesticides, called minimum risk pesticide products, are exempt from FIFRA registration as they pose little or no risk to humans and the environment and fulfill several conditions. The EPA has a list of active and inert ingredients allowed in minimum risk pesticide products. The active ingredient list, which is just shy of 50 compounds, primarily constitutes of plant-based chemicals. This list has not been updated in nearly ten years.
Chitosan is a naturally occurring polymer that is found in the exoskeletons of crustaceans and insects and cell walls of fungi. It was first registered under FIFRA in 1980 and is an antimicrobial agent and fungicide. It is approved for use on indoor and outdoor plants. Additionally, it is used in textiles, cosmetics, beverage processing, and water treatment. Testing data have shown that chitosan is expected to pose no human health or ecological risks. Based on these factors, in 2018, Tidal Vision Products, LLC asked the EPA to add chitosan to the list of active ingredients allowed in minimum risk pesticide products.
In 2020, the EPA requested public comments on the proposal to include chitosan and chitosan salts (which are formed when chitosan is mixed with acids that are listed in the minimum risk category) to minimum risk active ingredients list. Additional data on chitosan salt’s potential effects on the environment was requested and was thereafter provided by the petitioner. Based on a review of the latest available data and public comments, the EPA decided to add chitosan and its salts to the minimum risk active ingredient list.