US EPA addresses ecological risks posed by four pyridines and pyrimidines herbicides

The U.S Environmental Protection Agency (EPA) is releasing a proposed interim decision for picloram and interim decisions for clopyralid, dithiopyr and triclopyr to address ecological risks.

The interim decision (ID) for dithiopyr finalizes enforceable mitigation measures to address spray drift risks of concern. The IDs for clopyralid and triclopyr finalize enforceable mitigation measures to address potential residues in compost in addition to spray drift. The compost mitigation measures for clopyralid and triclopyr include label language focusing on:

• Reducing compost contamination by prohibiting off-site composting of treated plant matter and manure from grazing animals until residues have adequately declined (both clopyralid and triclopyr);

• Requiring pasture and turf applicators to notify the property owners/operators of the compost prohibition, and for the applicator to keep a record of this notification for two year (clopyralid only);

• Requiring registrants to participate in a stewardship program and provide educational outreach for those affected by herbicide residues in compost (clopyralid only); and,

• Removal of residential use on turf language from all labels (clopyralid only).
  

In addition to the IDs, EPA is also releasing the proposed interim decision (PID) for picloram for public comment. The PID for picloram proposes mitigation similar to the mitigation measures in the clopyralid ID.

Interim registration review decisions impose risk mitigation measures necessary to protect the environment pending additional assessments including an endangered species assessment.

The pyridines and pyrimidines are a class of herbicides used to control broadleaf weeds, woody brush and aquatic plants in both agricultural and non-agricultural settings that vary among the herbicides. Agricultural use sites include grains, fruits, vegetables and other crops. Non-agricultural use sites include turf, industrial areas, roadsides and other non-agricultural sites.

Upon publication of the Federal Register notice, the IDs will be available in docket numbers EPA-HQ-OPP-2014-0167 (clopyralid), EPA-HQ-OPP-2013-0750 (dithiopyr) and EPA-HQ-OPP-2014-0576 (triclopyr) and the PID will be available for a 60-day public comment period in docket number EPA-HQ-OPP-2013-0740 (picloram) at www.regulations.gov.  

After reviewing and considering the public comments received on the proposed interim decision for picloram, EPA will proceed with the registration review process and issue the picloram ID.

The Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) requires EPA to periodically review pesticides to ensure that risk assessments reflect the best available science. The proposed interim decision and interim decisions are part of a multi-step process to identify risks as well as actions that can mitigate risks.  

Additional information on the pyridine and pyrimidine herbicides proposed and interim decisions can be found on EPA’s website.