United States       Prevention, Pesticides     EPA712-C-96-010
          Environmental Protection    and Toxic Substances     August 1996
          Agency         (7101)
&EPA    Product Properties
          Test Guidelines
          OPPTS 830.1670
          Discussion of Formation
          of Impurities

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                           INTRODUCTION
     This guideline is one  of a series  of test guidelines  that have been
developed by the Office of Prevention, Pesticides and Toxic Substances,
United States Environmental Protection Agency for use in the testing  of
pesticides and toxic substances, and the  development of test data that must
be submitted to the Agency  for review under Federal regulations.

     The Office of Prevention, Pesticides and Toxic Substances (OPPTS)
has  developed this guideline through  a  process of harmonization that
blended the testing  guidance and requirements that existed in the Office
of Pollution Prevention and Toxics  (OPPT) and appeared in Title 40,
Chapter I,  Subchapter R of the Code of Federal Regulations  (CFR), the
Office of Pesticide Programs (OPP) which appeared in publications of the
National Technical  Information Service (NTIS) and  the guidelines pub-
lished by the Organization  for Economic Cooperation and Development
(OECD).

     The purpose of harmonizing these guidelines into a single set  of
OPPTS  guidelines is to minimize variations among the testing procedures
that must be performed to meet the data  requirements of the U. S. Environ-
mental Protection Agency  under the Toxic  Substances Control Act (15
U.S.C. 2601) and the Federal Insecticide,  Fungicide and Rodenticide Act
(7U.S.C. I36,etseq.).

     Final  Guideline Release: This document is available from the U.S.
Government Printing Office, Washington, DC 20402 on The Federal Bul-
letin  Board.   By  modem  dial   202-512-1387,   telnet   and  ftp:
fedbbs.access.gpo.gov     (IP     162.140.64.19),    internet:     http://
fedbbs.access.gpo.gov, or call 202-512-0132 for disks or paper copies.
This guideline is available in ASCII and PDF (portable document format)
from the EPA Public Access Gopher (gopher.epa.gov) under the heading
"Environmental Test Methods and Guidelines."

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OPPTS 830.1670  Discussion of formation of impurities.
     (a) Scope—(1) Applicability. This guideline is intended to meet test-
ing  requirements  of  both  the Federal  Insecticide,   Fungicide,  and
Rodenticide Act (FIFRA) (7 U.S.C. 136, et seq.) and the Toxic Substances
Control Act (TSCA) (15 U.S.C. 2601).

     (2) Background.  The source material used in developing this har-
monized OPPTS test guideline is 40 CFR 158.167 Discussion of formula-
tion of impurities.

     (b) Information required. The applicant must provide a discussion
of the  impurities that may be present in the  product,  and why  they may
be present. The discussion should be based on established chemical theory
and on what the  applicant knows about the  starting materials, technical
grade of active  ingredient, inert ingredients, and production or formulation
process. If the applicant has reasons to believe that an impurity that EPA
would  consider toxicologically significant may be present, the discussion
must include  an expanded discussion of the possible formation of the im-
purity and the amounts at which it might be present. The impurities which
must be discussed are the following, as applicable:

     (c) Technical grade active ingredients  and products produced by
an integrated system.  (1) Each impurity associated with the active ingre-
dient which was found to be present in any analysis of the product con-
ducted by or for the applicant.

     (2) Each other  impurity which the applicant  has reason to  believe
may be present in his product at any time before use at a level  «0.1
percent (1,000 ppm) by weight of the technical grade of the active ingredi-
ent, based on what he knows about the following:

     (i) The composition (or composition range) of each starting material
used to produce his product.

     (ii) The impurities which he knows are present (or believes are likely
to be present) in the starting  materials, and the known or presumed level
(or range of levels) of these impurities.

     (iii) The intended reactions and  side reactions which may occur in
the production of the product, and the relative  amounts of byproduct impu-
rities produced by such reactions.

     (iv) The possible  degradation of the ingredients in the product after
its production but prior to its use.

     (v) Post-production reactions between the ingredients in the product.

     (vi) The  possible migration of components of packaging materials into
the pesticide.

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     (vii) The possible carryover of contaminants from use  of production
equipment previously used to produce other products or substances.

     (viii) The process control, purification and quality control measures
used to produce the product.

     (d) Products not produced by an integrated system. Each impurity
associated with the  active ingredient which the applicant has  reason to
believe  may be  present  in the product at any time before  use at a
level >0.1 percent (1,000 ppm) by weight of the product based on what
he knows about the following:

     (1) The possible  carryover  of impurities present in any registered
product which serves as the source  of any of the product's active ingredi-
ents. The  identity and level of impurities in the registered source need
not be discussed or quantified unless known to the formulator.

     (2) The possible carryover of impurities present in the inert ingredi-
ents in the product.

     (3) Possible reactions occurring during the formulation of the product
between any of its active ingredients, between the active ingredients and
inert ingredients,  or between  the  active ingredient  and the production
equipment.

     (4) Post-production reactions between any of the product's  active in-
gredients and any other component of the product or its packaging.

     (5) Possible migration of packaging materials into the product.

     (6) Possible contaminants  resulting from earlier use of equipment to
produce other products.

     (e) Expanded discussion. On  a case-by-case basis, the Agency may
require an expanded discussion of information on impurities:

     (1) From other possible chemical reactions.

     (2) Involving other ingredients.

     (3) At additional points in the production or formulation process.

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