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Pesticide Science Policies: Water Treatment Effects on Pesticide Removal and Transformation; Notice of Availability

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Environmental Protection Agency (EPA).




To assure that EPA's policies related to implementing the Food Quality Protection Act of 1996 (FQPA) are transparent and open to public participation, EPA is soliciting comments on the pesticide draft science policy document entitled “The Incorporation of Water Treatment Start Printed Page 58486Effects on Pesticide Removal and Transformations in FQPA Drinking Water Assessments.” This notice is one in a series concerning science policy documents related to the implementation of the Federal Food, Drug, and Cosmetic Act (FFDCA), as amended by FQPA.


Comments for the draft science policy document, identified by docket control number OPP-00731, must be received on or before January 22, 2002.


Comments may be submitted by mail, electronically, or in person. Please follow the detailed instructions for each method as provided in Unit I. of the SUPPLEMENTARY INFORMATION. To ensure proper receipt by EPA, it is imperative that you identify docket control number OPP-00731 in the subject line on the first page of your response.

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James Hetrick, Office of Prevention, Pesticides and Toxic Substances (7505C), Environmental Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460; telephone number: (703) 305-5237; fax number: (703) 305-6309; e-mail address:

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I. General Information

A. Does this Action Apply to Me?

You may be potentially affected by this action if you manufacture or formulate pesticides. Potentially affected categories and entities may include, but are not limited to:

CategoriesNAICS codesExamples of potentially affected entities
Pesticide producers32532Pesticide manufacturers
Pesticide formulators

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 could also be affected. The North American Industrial Classification System (NAICS) codes have been provided to assist you and others in determining whether or not 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 Additional Information, Including Copies of this Document or Other Related Documents?

1. Electronically. You may obtain electronic copies of this document, the draft science policy document, and certain other related documents that might be available from the Office of Pesticide Programs' Home Page at​pesticides/​. On the Office of Pesticide Programs' Home Page select “FQPA” and then look up the entry for this document under “Science Policies.” You can also go directly to the listings at the EPA Home Page at​. On the Home Page select “Laws and Regulations,” “Regulations and Proposed Rules,” and then look up the entry for this document under “Federal Register—Environmental Documents.” You can go directly to the Federal Register listings​fedrgstr/​.

2. Fax-on-demand. You may request a faxed copy of the draft science policy document, as well as supporting information, by using a faxphone to call (202) 401-0527. Select item 6088 for the document entitled “The Incorporation of Water Treatment Effects on Pesticide Removal and Transformations in FQPA Drinking Water Assessments.” You may also follow the automated menu.

3. In person. The Agency has established an official record for this action under docket control number OPP-00731. In addition, the documents referenced in the framework notice, which published in the Federal Register of October 29, 1998 (63 FR 58038) (FRL-6041-5), under docket control number OPP-00557, are considered as part of the official record for this action under docket control number OPP-00731 even though not placed in the official record. The official record consists of the documents specifically referenced in this action, and other information related to this action, including any information claimed as Confidential Business Information (CBI). This official record includes the documents that are physically located in the docket, as well as the documents that are referenced in those documents. The public version of the official record does not include any information claimed as CBI. The public version of the official record, which includes printed, paper versions of any electronic comments submitted during an applicable comment period is available for inspection in the Public Information and Records Integrity Branch (PIRIB), Rm. 119, Crystal Mall #2, 1921 Jefferson Davis Hwy., Arlington, VA, from 8:30 a.m. to 4 p.m., Monday through Friday, excluding legal holidays. The PIRIB telephone number is (703) 305-5805.

C. How and to Whom Do I Submit Comments?

You may submit comments through the mail, in person, or electronically. To ensure proper receipt by EPA, it is imperative that you identify docket control number OPP-00731 in the subject line on the first page of your response.

1. By mail. Submit your comments to: Public Information and Records Integrity Branch (PIRIB), Information Resources and Services Division (7502C), Office of Pesticide Programs (OPP), Environmental Protection Agency, 1200 Pennsylvania, Ave., NW., Washington, DC 20460.

2. In person or by courier. Deliver your comments to: Public Information and Records Integrity Branch (PIRIB), Information Resources and Services Division (7502C), Office of Pesticide Programs (OPP), Environmental Protection Agency, Rm. 119, Crystal Mall #2, 1921 Jefferson Davis Hwy., Arlington, VA. The PIRIB is open from 8 a.m. to 4 p.m., Monday through Friday, excluding legal holidays. The PIRIB telephone number is (703) 305-5805.

3. Electronically. You may submit your comments electronically by e-mail to:, or you can submit a computer disk as described above. Do not submit any information electronically that you consider to be CBI. Avoid the use of special characters and any form of encryption. Electronic submissions will be accepted in WordPerfect 6.1/8.0 or ASCII file format. All comments in electronic form must be identified by docket control number OPP-00731. Electronic comments may also be filed online at many Federal Depository Libraries.

D. How Should I Handle CBI That I Want to Submit to the Agency?

Do not submit any information electronically that you consider to be CBI. You may claim information that you submit to EPA in response to this document as CBI by marking any part or all of that information as CBI. Information so marked will not be disclosed except in accordance with procedures set forth in 40 CFR part 2. In addition to one complete version of the comment that includes any information claimed as CBI, a copy of the comment that does not contain the information claimed as CBI must be submitted for inclusion in the public version of the official record. Information not marked confidential will be included in the public version Start Printed Page 58487of the official record without prior notice. If you have any questions about CBI or the procedures for claiming CBI, please consult the person listed under FOR FURTHER INFORMATION CONTACT.

E. What Should I Consider As I Prepare My Comments for EPA?

EPA invites you to provide your views on the various draft science policy documents, new approaches we have not considered, the potential impacts of the various options (including possible unintended consequences), and any data or information that you would like the Agency to consider. You may find the following suggestions helpful for preparing your comments:

1. Explain your views as clearly as possible.

2. Describe any assumptions that you used.

3. Provide solid technical information and/or data to support your views.

4. If you estimate potential burden or costs, explain how you arrived at the estimate.

5. Indicate what you support, as well as what you disagree with.

6. Provide specific examples to illustrate your concerns.

7. Make sure to submit your comments by the deadline in this notice.

8. At the beginning of your comments (e.g., as part of the “Subject” heading), be sure to properly identify the document you are commenting on. To ensure proper receipt by EPA, it is imperative that you identify docket control number OPP-00731 in the subject line on the first page of your response. You may also provide the name, date, and Federal Register citation.

II. Background Information

On August 3, 1996, FQPA was signed into law. The FQPA significantly amended the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) and the FFDCA. Among other changes, FQPA established a stringent health-based standard (“a reasonable certainty of no harm”) for pesticide residues in foods to assure protection from unacceptable pesticide exposure and strengthened health protections for infants and children from pesticide risks.

Thereafter, the Agency established the Food Safety Advisory Committee (FSAC) as a subcommittee of the National Advisory Council for Environmental Policy and Technology (NACEPT) to assist in soliciting input from stakeholders and to provide input to EPA on the broad policy choices facing the Agency and on strategic direction for the Office of Pesticide Programs (OPP). The Agency has used the interim approaches developed through discussions with FS AC to make regulatory decisions that meet the new FFDCA standard, but that could be revisited if additional information became available or as the science evolved. In addition, the Agency seeks independent review and public participation, generally through presentation of the science policy issues to the FIFRA science advisory panel (SAP) a group of independent, outside experts who provide peer review and scientific advice to OPP.

During 1998 and 1999, EPA and the United States Department of Agriculture (USDA) established a second subcommittee of NACEPT, the Tolerance Reassessment Advisory Committee (TRAC) to address FFDCA issues and implementation. TRAC comprised more than 50 representatives of affected user, producer, consumer, public health, environmental, states, and other interested groups. The TRAC met from May 27, 1998, through April 29, 1999.

In order to continue the constructive discussions about FFDCA, EPA and USDA have established, under the auspices of NACEPT, the Committee to Advise on Reassessment and Transition (CARAT). The CARAT provides a forum for a broad spectrum of stakeholders to consult with and advise the Agency and the Secretary of Agriculture on pest and pesticide management transition issues related to the tolerance reassessment process. The CARAT is intended to further the valuable work initiated by the FSAC and TRAC toward the use of sound science and greater transparency in regulatory decision making, increased stakeholder participation, and reasonable transition strategies that reduce risks without jeopardizing American agriculture and farm communities.

As a result of the 1998 and 1999 TRAC process, EPA decided that the implementation process and related policies would benefit from providing notice and comment on major science policy issues. The TRAC identified nine science policy areas it believed were key to implementation of tolerance reassessment. EPA agreed to provide one or more documents for comment on each of the nine issues by announcing their availability in the Federal Register. In a notice published in the Federal Register of October 29, 1998 (63 FR 58038), EPA described its intended approach. Since then, EPA has been issuing a series of draft documents concerning the nine science policy issues. This notice announces the availability of the draft science policy document concerning drinking water treatment.

III. Summary of “The Incorporation of Water Treatment Effects on Pesticide Removal and Transformations in Food Quality Protection Act Drinking Water Assessments”

The FQPA of 1996 requires that all tolerances for pesticide chemical residues in or on food consider anticipated dietary exposure and all other exposures for which there is reliable information. Drinking water is considered a potential pathway of dietary exposure to pesticides. Because drinking water for a large percentage of the population is derived from public water systems which normally treat raw water prior to consumption, the impact of water treatment on pesticide removal and transformation needs to be considered in drinking water exposure for risk assessments completed under FQPA. Treated drinking water for the purpose of FQPA exposure assessment will be defined as ambient ground or surface water which is either chemically or physically altered using technology prior to human consumption. Therefore, the objectives of this science policy paper are to:

1. Present a preliminary literature review on the impact of different treatment processes on pesticide removal and transformation in treated drinking water derived from ground and surface water sources.

2. Describe how OPP will consider the impacts of drinking water treatment in drinking water exposure assessments under FQPA.

IV. Literature Review

A wide variety of factors must be taken into account to assess the impact of drinking water treatment on the levels of different pesticides in drinking water. It is important to note that a sizeable proportion of the nation, approximately 23 million people, obtain their drinking water from private wells and other sources that undergo no treatment. For those drinking water sources that are treated, available survey information establishes that there are many distinct types of water treatment processes (and many more combinations of processes) in use throughout the United States. Nearly all public water supply systems use some form of disinfection, and a series of conventional treatment processes (coagulation-flocculation, sedimentation, and filtration). The processes that appear to have the most impact on pesticide removal granular Start Printed Page 58488activated carbon (GAC) and powdered activated carbon (PAC) - are commonly found or used in larger water supply systems but, because of high costs, are rarely used by the smallest systems. Other methods, such as “softening,” reverse osmosis, and air stripping are also less frequently used to remediate water quality concerns. In sum, there is enormous spatial and temporal variability in the types of treatment applied to drinking water.

EPA's preliminary review of the literature indicates that conventional treatment (such as coagulation/flocculation, sedimentation, and filtration) has little or no effect on the removal of mobile (hydrophilic or lipophobic) pesticides. Disinfection and softening can facilitate alteration in the chemical structure of the pesticide, or transformation. The type of disinfectant used and the length of contact time between the water and disinfectant are factors which affect the impact on pesticide transformation. There is little information on the chemical identity of transformation products formed as the result of disinfection. However, disinfection can produce toxic by-products of some pesticides (e.g., oxons from organophospates). The impact of softening on pesticide transformation is dependent on the potential for alkaline-catalyzed hydrolysis of the pesticide.

The FIFRA SAP evaluated the literature review and concurred with the conclusions (​pesticides/​scipoly/​sap/​2000/​index.htm#september). The SAP stated that immobile (hydrophobic/lipophilic) pesticides may be removed by conventional water treatment processes.

V. Proposed Policy

OPP is announcing and seeking public comment on a policy to provide a systematic approach for considering drinking water treatment effects on pesticide removal and transformation in FQPA risk assessments. Because most surface source drinking water receives some form of water treatment prior to human consumption, the proposed treatment policy is generally applicable to surface source drinking water. A similar assumption cannot be made for drinking water systems using ground water because of the importance of private wells in rural areas. Private wells are not generally linked to water treatment systems prior to human consumption. This policy is based on scientific conclusions reached as a result of OPP's literature review and on our assessment of the availability of information for specific pesticides on water treatment effects:

  • The Environmental Fate and Effects Division (EFED) will provide available information on the potential and measured effects from drinking water treatment (e.g., flocculation, coagulation, sedimentation, filtration, chlorination, softening, and GAC/PAC treatment) to the HED Metabolism Assessment Review Committee (MARC). The MARC will evaluate this information and determine which, if any, transformation and degradation products might be of toxicological concern. This information will also be considered in FQPA Safety Factor decisions.
  • OPP will not generally conclude that treatment mitigates exposure for a specific pesticide without supporting evidence. Therefore, if sufficient pesticide-specific information is not available on effects of water treatment processes, or if sufficient information is not available on the extent to which specific processes are employed within the pesticide use area, FQPA drinking water assessments will be conducted using pesticide concentrations in raw or ambient waters to represent pesticide concentrations in finished drinking water. This policy is based on the fact that conventional water treatment processes (coagulation/flocculation, sedimentation, and filtration) are not expected to remove mobile pesticides during treatment.
  • If sufficient pesticide-specific information is available on effects of a water treatment processes, as well as information on the extent to which such processes are employed within the pesticide use area, EFED will attempt to describe quantitatively the potential effects of drinking water treatment for that pesticide in the drinking water assessment. This description will include effects of degradation and formation of transformation products.
  • Monitoring data on finished drinking water may also represent in aggregate the effects of treatment in the study area. However, because of the inherent variability associated with water treatment processes, with source water quality, and the limited availability of monitoring data on pesticides in finished drinking water, extrapolating such results to areas outside of the area monitored must be considered on a case-by-case basis. It is anticipated that quantitation of drinking water treatment effects will be limited to pesticides with extensive monitoring data on finished water (e.g., atrazine) or pesticides with monitoring data on finished water from focused or limited use areas (e.g., molinate). Extrapolating treatment effects across compounds with similar structures will be considered on a case-by-case basis.

VI. Questions for Public Comment

1. Do the scientific data demonstrate clear quantitative relationships exist between the physical/chemical properties of particular pesticide classes and the impacts of specific water treatment processes?

2. Based on its technical review of the literature on the impacts of different treatment processes on levels of pesticide residues in drinking water, OPP is leaning toward an interim approach which assumes, in the absence of representative pesticide-specific water plant monitoring data, that residues in finished drinking water will be the same as levels in such water prior to treatment. Given the objective of accurately estimating pesticide concentrations in drinking water, do the scientific data support this approach? How would an approach be developed based on the state of knowledge about the impact of treatment on pesticides? Under what circumstances can OPP use data on the impacts of a specific treatment process on several pesticides in a chemical class to support a general conclusion about all pesticide in that class?

3. During disinfection with chlorine, pesticides such as organophosphates can be oxidized to form toxic degradation products. What other classes of pesticides may be transformed by drinking water treatment processes to form toxic byproducts? What issues related to pesticide transformation should OPP be aware of?

4. Laboratory jar tests are often employed to determine if a regulated contaminant, including some pesticides, in raw water can be removed by a given treatment process. What are the advantages and disadvantages of using results of jar tests as the basis of evaluating whether the pesticide will be eventually removed in the actual water treatment plant? How might these results be used to adjust raw water concentrations for use in human health risk assessment? What are the advantages and disadvantages of using other types of data, e.g., paired samples from field monitoring, or pilot plant data.

5. Studies cited in the literature review indicate that many factors, such as raw water composition, water treatment method, and treatment plant conditions, may affect the removal of pesticides. What issues should OPP be considering in determining the potential impact of these factors on the percent removal and transformation of Start Printed Page 58489pesticides by different water treatment plants?

6. What additional water treatment data from other studies, which either support or are inconsistent or contradict the data presented in the preliminary literature review, should OPP consider? Please submit any data that would provide information on the impacts of water treatment on additional pesticides or classes of pesticides.

7. For example, some pesticides, including carbamates and organophosphates, with hydrolysis half-lives of less than 1 day in alkaline (pH 9) water are observed to be “removed” during lime-soda softening (pH 10~~11) by alkaline hydrolysis. Can this observation be generalized in predicting whether a pesticide with alkaline abiotic hydrolysis half-life of less than 1 day will be “removed” through water treatment?

8. The effects of water treatment on pesticide residues in drinking water can be assessed by regression modeling of important parameters with removal efficiency, experimental or laboratory studies, and actual field monitoring. What other approaches or methods can be used to assess water treatment effects? What are the pros and cons of these methods?

9. What types of data are needed regarding the extent and manner of use of a particular drinking water treatment process in order to use the data on the impact of such method on pesticide concentrations in finished drinking water in a deterministic or probabilistic exposure assessment?

VII. Policies Not Rules

The draft science policy document discussed in this notice is intended to provide guidance to EPA personnel and decisionmakers, and to the public. As a guidance document and not a rule, the policy in this guidance is not binding on either EPA or any outside parties. Although this guidance provides a starting point for EPA risk assessments, EPA will depart from its policy where the facts or circumstances warrant. In such cases, EPA will explain why a different course was taken. Similarly, outside parties remain free to assert that a policy is not appropriate for a specific pesticide or that the circumstances surrounding a specific risk assessment demonstrate that a policy should be abandoned.

EPA has stated in this notice that it will make available revised guidance after consideration of public comment. Public comment is not being solicited for the purpose of converting any policy document into a binding rule. EPA will not be codifying this policy in the Code of Federal Regulations. EPA is soliciting public comment so that it can make fully informed decisions regarding the content of each guidance document.

The “revised” guidance will not be unalterable. Once a “revised” guidance document is issued, EPA will continue to treat it as guidance, not a rule. Accordingly, on a case-by-case basis EPA will decide whether it is appropriate to depart from the guidance or to modify the overall approach in the guidance. In the course of inviting comment on each guidance document, EPA would welcome comments that specifically address how a guidance document can be structured so that it provides meaningful guidance without imposing binding requirements.

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List of Subjects

  • Environmental protection
  • Administrative practice and procedure
  • Agricultural commodities
  • Pesticides and pests
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Dated: November 8, 2001.

Stephen Johnson,

Assistant Administrator for Prevention, Pesticides and Toxic Substances.

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[FR Doc. 01-28973 Filed 11-20-01; 8:45 am]