EPA Proposes Updated Mitigation Measures For Atrazine To Protect Aquatic Ecosystems

The U.S. Environmental Protection Agency (EPA) has released updated mitigation measures for the herbicide atrazine, aiming to safeguard aquatic ecosystems and federally protected species. The proposal incorporates a revised concentration-equivalent level of concern (CE-LOC) and a flexible point-based mitigation system, inviting public comment over the next 60 days.

Revised CE-LOC Standards To Strengthen Environmental Protection

The updated mitigation measures reduce the CE-LOC for atrazine to 9.7 µg/L from the previously proposed 15 µg/L, enhancing protection for aquatic plant communities. EPA's decision followed scientific reviews, including an evaluation by the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) Scientific Advisory Panel, which identified significant risks posed by atrazine runoff to sensitive ecosystems​​.

New Flexible Point-Based Mitigation System

Under the proposed system, growers in watersheds with atrazine concentrations exceeding the CE-LOC will be required to achieve mitigation points based on the predicted concentration of atrazine in their area. Fields in watersheds with concentrations between 9.7 and 45.4 µg/L need three points, while those above 45.4 µg/L require six points. These points can be earned through measures like conservation tillage, vegetative buffer strips, or installing irrigation systems​​.

The EPA’s Herbicide Strategy, finalised in August 2024, informed the new approach. By expanding the mitigation menu, growers now have up to 40 options tailored to various crop types and geographic conditions​​.

Enhanced Surface Water Monitoring Data

The EPA's mitigation plans integrate robust water monitoring data from programs such as the Atrazine Ecological Exposure Monitoring Program (AEEMP) to pinpoint vulnerable watersheds. Updated maps identify HUC-12 watersheds exceeding the CE-LOC, aiding targeted mitigation efforts​​.

Implications For Farmers And Stakeholders

Atrazine remains an economically vital herbicide for crops like corn and sorghum, with benefits including increased grower revenue and effective weed management. While the proposed restrictions, such as reduced annual application rates and a ban on application during rain or saturated soil conditions, may impact some farming practices, the EPA emphasizes that the flexible mitigation system minimizes disruption​​.

Public Involvement And Next Steps

The EPA encourages public participation through a 60-day comment period. Stakeholders can access details on the proposal, including mitigation measures, via the EPA’s official website and submit comments through the Federal Register​.

These updates reflect the EPA’s commitment to balancing agricultural needs with environmental conservation. The mitigation measures are expected to reduce atrazine runoff significantly, safeguarding aquatic ecosystems and aligning with the agency’s broader Herbicide Strategy.