

[Federal Register: August 11, 2006 (Volume 71, Number 155)]
[Notices]               
[Page 46226-46227]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr11au06-69]                         

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ENVIRONMENTAL PROTECTION AGENCY

[EPA-HQ-OPP-2005-0129; FRL-8071-9]

 
Final NAFTA Guidance for Conducting Terrestrial Field Dissipation 
Studies

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice.

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SUMMARY: Under the North American Free Trade Agreement (NAFTA), EPA and 
the Canadian Pest Management Regulatory Agency (PMRA) have agreed to 
harmonize their testing guidelines so that one set of tests can be used 
for the registration of pesticides in Canada and the United States. The 
NAFTA harmonized guidance for terrestrial field dissipation (TFD) 
studies are conducted to demonstrate the transformation, transport, and 
fate of pesticides under representative actual use conditions. These 
field studies are needed to substantiate the physicochemical, mobility, 
and biotransformation data from laboratory studies. Environmental fate 
studies have shown that pesticide dissipation may proceed at different 
rates under field conditions and may result in degradates forming at 
levels different from those observed in laboratory studies. The 
objective of this guidance document is to help ensure that TFD studies 
are conducted in a manner that will provide risk assessors and risk 
managers with more confidence in the data generated and with a better 
understanding of the assumptions and limitations of the data and 
estimated half-lives of the pesticide. The proposed guidance document 
for TFD studies was published in the Federal Register on June 15, 2005 
(FRL-7713-7). After reviewing the public comments for this Notice, EPA 
developed a final guidance document, which can be found at: http://www.epa.
 gov/oppefed1/ecorisk--ders/terrestrial-- field-- dissipation--

guidance.pdf. EPA's response to public comments can be found in the 
public docket: EPA-HQ-OPP-2005-0129.

FOR FURTHER INFORMATION CONTACT: Mark Corbin, Environmental Fate and 
Effects Division (7507P), Office of Pesticide Programs, Environmental 
Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460-
0001; telephone number: (703) 605-0033; fax number: (703) 305-6309; e-
mail address: corbin.mark@epa.gov.

SUPPLEMENTARY INFORMATION:

I. General Information

A. Does this Action Apply to Me?

     You may be potentially affected by this action if you are an 
agricultural producer, food manufacturer, or pesticide manufacturer. 
Potentially affected entities may include, but are not limited to:
     Crop production (NAICS code 111)
     Animal production (NAICS code 112)
     Food manufacturing (NAICS code 311)
     Pesticide manufacturing (NAICS code 32532)
    This listing is not intended to be exhaustive, but rather provides 
a guide for readers regarding entities likely to be affected by this 
action. Other types of entities not listed in this unit could also be 
affected. The North American Industrial Classification System (NAICS) 
codes have been provided to assist you and others in determining 
whether this action might apply to certain entities. If you have any 
questions regarding the applicability of this action to a particular 
entity, consult the person listed under FOR FURTHER INFORMATION 
CONTACT.

B. How Can I Get Copies of this Document and Other Related Information?

    1. Docket. EPA has established a docket for this action under 
docket identification (ID) number EPA-HQ-OPP-2005-0129. Publicly 
available docket materials are available either in the electronic 
docket at http://www.regulations.gov, or, if only available in hard 

copy, at the Office of Pesticide Programs (OPP) Regulatory Public 
Docket in Rm. S-4400, One Potomac Yard (South Building), 2777 S. 
Crystal Drive, Arlington, VA. The hours of operation of this Docket 
Facility are from 8:30 a.m. to 4 p.m., Monday through Friday, excluding 
legal holidays. The Docket telephone number is (703) 305-5805.
    2. Electronic access. You may access this Federal Register document 
electronically through the EPA Internet under the ``Federal Register'' 
listings at http://www.epa.gov/fedrgstr.


II. Background

A. What Action is the Agency Taking?

    The Terrestrial Field Dissipation study has been a basic 
requirement for registrants of new and existing pesticides since 1982. 
While laboratory environmental fate studies are designed to address one 
dissipation process at a time, terrestrial field dissipation studies 
address pesticide loss as a combined result of chemical and biological 
processes (e.g., hydrolysis, photolysis, microbial transformation) and 
physical migration (e.g., volatilization, leaching, plant uptake). Data 
from these studies can reduce potential overestimation of exposure and 
risk and can confirm assumptions of low levels of toxic degradates. 
Results can be used to propose scenario-specific effective risk 
mitigation.
    In general, the terrestrial field dissipation study results should 
allow the risk assessor to:

[[Page 46227]]

     Compare predicted routes of dissipation identified in the 
laboratory with those measured in the field;
     Characterize the rates of dissipation of the parent 
compound and formation and decline of the major and/or toxicologically 
significant transformation products under field conditions;
     Characterize the rates and relative importance of the 
different transport processes, including leaching, runoff, and 
volatilization;
     Establish the distribution of the parent compound and the 
major transformation products in the soil profile;
     Characterize the persistence of the parent compound and 
major transformation products in soil, including retention and residue 
carryover in the soil to the following crop season; and
     Characterize the effect(s) of different typical pesticide 
formulation categories, where applicable.
    EPA and PMRA have developed harmonized guidance for conducting 
terrestrial field dissipation studies so that one set of tests can be 
used for registration of a pesticide in Canada, the United States, and 
Mexico. In developing this guidance document, EPA and PMRA conducted an 
extensive outreach and review program, soliciting input from 
stakeholders and the technical community through several forums: Three 
symposia, one Scientific Advisory Panel (SAP) meeting, and one 
workshop. Working closely with its stakeholders, PMRA and EPA developed 
a conceptual model for designing terrestrial studies that will evaluate 
the overall dissipation of a pesticide in the field. The conceptual 
model, which is specific for each pesticide, is based on the chemical's 
physicochemical properties, laboratory environmental fate studies, 
formulation type and intended use pattern. On June 15, 2005, the Agency 
published the draft harmonized guidance and conceptual model in the 
Federal Register and asked for comments. After reviewing all the 
comments, PMRA and EPA developed the final guidance, which can be found 
at the following address: http://www.epa.gov/ oppefed1/ecorisk--ders/ 

terrestrial--field--dissipation-- guidance.pdf.

B. What is the Agency's Authority for Taking this Action?

    This action is being taken under the Federal Insecticide, 
Fungicide, and Rodenticide Act (FIFRA).

List of Subjects

    Environmental protection, Terrestrial field dissipation, NAFTA 
harmonized guidance.


    Dated: August 3, 2006.
Steven Bradbury,
Director, Environmental Fate and Effects Division, Office of Pesticide 
Programs.
[FR Doc. E6-13042 Filed 8-10-06; 8:45 am]

BILLING CODE 6560-50-S
