[7/8/2024]. Today, the U.S. Environmental Protection Agency (EPA) is announcing an update to the level at which atrazine is expected to adversely affect aquatic plants. The new revised atrazine concentration of 9.7 micrograms per liter (µg/L), which was derived following an August 2023 peer review, will be used to develop a revised regulatory decision to help protect aquatic plants as well as fish, invertebrates, and amphibians.
Atrazine is one of the most widely used herbicides in the United States. It is used to control annual broadleaf and grass weeds in a variety of agricultural crops, primarily corn, sorghum, and sugarcane. Atrazine products are also registered for numerous other uses including macadamia nuts, guava, fallow crop lands, and turfgrass.
The level at which atrazine is expected to adversely affect aquatic plants is also known as the concentration-equivalent level of concern or CE-LOC. Included in this announcement is an EPA memorandum that provides details on updates to EPA’s database of aquatic plant community studies and revised exposure modeling. Also included is an updated map that shows where the level of concern is expected to be exceeded. Collectively, these updates resulted in the removal of millions of acres of land from the 2022 map of watersheds that were expected to exceed the level of concern and added a much smaller number of acres in other areas of the country. Later this year, EPA plans to update its 2022 atrazine mitigation proposal to reflect the revised level of concern and the corrections to the exposure modeling, as well as to incorporate feedback received during the 2022 public comment period. EPA will take public comment on the revised mitigation proposal and also release a response to comments on the 2022 proposed revisions to the interim decision at that time.
Background
In its 2016 atrazine ecological risk assessment, EPA determined that the scientifically derived level of atrazine, measured as a 60-day average, that negatively impacted the aquatic environment was 3.4 µg/L.
Since that time, questions about the scientific integrity of the assessment of atrazine were raised after the previous Administration directed career managers to exclude studies related to the effects of atrazine from being used as a basis for ecological risk management. The career managers refused to carry out the direction and instead, in September 2020, EPA set a less protective level for atrazine at 15 µg/L that was based on a policy decision rather than a scientific one. The following month, EPA received a lawsuit alleging that the Agency violated its duties under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) by making its Atrazine Interim Registration Review Decision without substantial supporting evidence. In August 2021, EPA sought a voluntary partial remand and on December 14, 2021, the Ninth Circuit Court of Appeals granted that remand, which provided the agency the opportunity to reevaluate it.
In August 2023, the Agency convened a meeting of the FIFRA Scientific Advisory Panel (SAP) to evaluate eleven studies and their associated publications, which EPA had used to calculate its science-based level of concern for atrazine of 3.4 µg/L. The SAP is a forum that provides independent scientific advice and recommendations on scientific issues related to pesticides. After the SAP, EPA also reevaluated two additional relevant studies based on public comments and letters to the Agency requesting reexamination. After indicating concurrence with the recommendations received from the SAP and taking into consideration its reevaluation of the additional two studies, EPA has recalculated the level of concern for atrazine as 9.7 µg/L as a 60-day average.
For additional information, please visit docket EPA-HQ-OPP-2013-0266 at www.regulations.gov.
Learn More About Atrazine
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Editorial Note on Atrazine Use in New Jersey:
The New Jersey Department of Enviromental Protection (NJDEP) Bureau of Quality Assurance and Environmental Monitoring Pesticide Evaluation and Monitoring Section (PEMS) published a summary of AGRICULTURAL PESTICIDE USE IN NEW JERSEY: 2018 SURVEY. This report and other New Jersey Pesticide Use Summaries are posted on the NJDEP website for public review.
The Introduction to this summary provides that PEMS began a series of pesticide use surveys in 1985 that address pesticide use by licensed applicators in the state of New Jersey for agriculture, golf courses, termite control, right-of-way, mosquito control, and lawn care. The agricultural use survey is conducted every three years and targets agricultural, nursery and greenhouse use of general and restricted use pesticides. Unlike most states, New Jersey code requires applicators to maintain pesticide records for two years and to submit use records to the state when requested.
NJDEP characterizes the regulative authority New Jersey Pesticide Control Code, N.J.A.C. 7:30-1 et.seq. as providing “an accuracy and level of response that is difficult to duplicate in a voluntary, nationwide survey. In fact, these New Jersey surveys almost represent a pesticide usage census rather than a probabilistic survey“. Additionally, NJDEP states: “Any review or discussion of the data collected in the 2000 agricultural pesticide use survey must focus on the uniqueness of New Jersey’s agriculture. A primary point to consider is the absence of a particular major crop. Due to New Jersey’s geographical location, climatic conditions allow the production of a tremendous selection of vegetables and fruits, and the state incorporates a vast collection of what are termed “truck farms”, where a variety of small crops are grown on the same farm. Therefore, although individual pesticides may dominate use on a particular crop, there is no group of pesticides that dominate use in the state. This is in contrast to many mid-western states, where corn herbicides represent the predominant use.“
This report focuses on the seventh (and last) survey completed in the agricultural use series (2018). Data collected on the ag use of the herbicide atrazine in 2018 shows that approximately 40,626 pounds of the active ingredient (ai) were applied; this is substantial relative to other ag use of herbicides (with the exception of glyphosate) which totals 451,360 pounds ai.
Ayers, M.A., Kennen, J.G., and Stackelberg, P.E., 2000, Water Quality in the Long Island–New Jersey Coastal Drainages New Jersey and New York, 1996–98: U.S. Geological Survey Circular 1201, 40 p., on-line at https://pubs.water.usgs.gov/circ1201.
Note from post-er: This repost is part of our curated outreach to growers enrolled in the NJAES Plant and Pest Advisory and was received from GovDelivery Communications Cloud on behalf of: U.S. EPA Office of Chemical Safety and Pollution Prevention · 707 17th St, Suite 4000 · Denver, CO 80202 · 1-800-439-1420. Links within the blog post were highlighted editorally for emphasis.