U.S. EPA takes next step in the review of anthraquinone

On April 7, 2022, the U.S. Environmental Protection Agency (EPA) is taking the next step in the registration review process for the pesticide anthraquinone by releasing the final work plan and draft human health and ecological risk assessments. Anthraquinone is registered for use as an avian repellent in both agricultural and non-agricultural settings. Agricultural uses consist of seed treatments for corn and rice, with the latter predominately in the Arkansas Grand Prairie, the Mississippi Delta, and the Gulf Coast. Non-agricultural uses include foliar applications to turf at airports, athletic fields, and other non-agricultural sites.

Registration Review

For registration review, EPA is releasing the anthraquinone final work plan (FWP) and draft risk assessments (DRAs). The Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) requires the Agency to periodically re-evaluate pesticides through registration review to ensure that risk assessments and pesticide decisions reflect the best available science. The FWP and DRAs are part of a multi-step process to identify risks of concern and to mitigate these risks.

With regard to the DRAs, these risk assessments are the product of an evaluation of available data on anthraquinone’s human health and environmental impacts.

EPA did not identify any dietary risks of concern from food and water exposure. Based on the calculations completed in the draft human health risk assessment, the Agency has identified potential cancer risk concerns from residential exposures to treated turf and occupational exposures for some pesticide handlers for each use. And because there are risk concerns from residential exposures alone, the aggregate exposures (i.e., combined dietary and residential exposures) therefore also result in risk concerns.

In light of the aggregate risks, EPA is working to expedite the implementation of mitigation measures in advance of the completion of registration review. Specifically, the registrant has agreed to prohibit use on residential turf sites, which EPA expects will eliminate the aggregate risks of concern when the label changes are fully implemented later this year.

The draft ecological risk assessment found potential adverse effects to birds, reptiles, amphibians, mammals, fish, aquatic invertebrates, and aquatic plants based on the data available. Potential risks to terrestrial invertebrates and plants as well as other taxa could not be fully assessed because there are multiple environmental fate and ecological effects data gaps. To address the identified data gaps, EPA plans to issue a Data Call-in (DCI) in April 2022 and consider the results of the data submitted in future anthraquinone risk assessments.

After reviewing and considering the public comments received on the DRAs, EPA will proceed with the next step in the registration review process and issue a proposed interim decision (PID). The PID will propose mitigation measures to address potential occupational and ecological risks. EPA expects to issue the PID for public comment in early 2023.

The public comment period for the DRAs is now open for 60 days. The FWP, DRAs and all supporting documents are available in the anthraquinone registration review docket EPA-HQ-OPP-2017-0326 at www.regulations.gov.

Request for Data

EPA, as part of its registration review process for anthraquinone, reviewed rice field trial data submitted by the sole anthraquinone registrant. The data indicated that use of anthraquinone as a rice seed treatment is expected to result in detectable pesticide residues in or on food or feed. At this time, however, there is no established tolerance to cover those residues in or on rice commodities; thus, any harvested rice commodities containing such residues will be adulterated. It is unlawful to ship adulterated commodities through interstate commerce. Previously, EPA did not have reason to believe that the use of anthraquinone on rice would result in residues in or on rice and thus had considered this rice seed use as a non-food use (not needing a tolerance).

EPA is working actively with the registrant to address all the data gaps present in this registration review case. This includes requiring that the registrant develop the data needed to establish tolerances for the rice seed treatment use by 2024. The Agency anticipates a tolerance would be established no sooner than 2024 to allow for developing complete and accurate data and to enable a thorough review by EPA.

In information EPA provided to Food and Drug Administration, the Agency states that there are no dietary (rice and water) risks of concern from the use of anthraquinone on treated rice for any population subgroups, including infants and children. EPA’s dietary assessment is conservative and protective of potential dietary exposures. Although there is some uncertainty in the dietary risk assessments due to incomplete residue chemistry and fate databases, the chronic non-cancer and cancer dietary assessments are not likely to underestimate dietary risks.

Thus, EPA has concluded there are no resulting risks of concern from the consumption of rice commodities that could enter or are already available from the channels of trade. Additionally, once residential turf use sites are removed from the label, there will be no aggregate risks of concern (i.e., combined dietary and residential exposures). Once the necessary data are available and evaluated, tolerances can be established for this use.