I am Dr. Barbara Petersen, President of Novigen Sciences, Inc., a scientific consulting firm located in Washington, D.C. I am a PhD Biochemist and have devoted over 20 years of my career to food additive, pesticide residue and food metabolism research. I am a member of the EPA’s Science Advisory Board’s Committee on Integrated Exposure Assessment. Over the past two years, our committee has considered a variety of proposed methods to assess exposure in two complex scenarios. These chemical exposure scenarios include one where there are a number of sources of a chemical exposure and a second where there are a number of chemicals with similar mechanisms of toxicity. Most of those methods have not been focussed on pesticide exposure assessment, but rather on other EPA mandated programs. In fact, the Office of Pesticide Programs has not yet presented their methodology for review by this committee. The existing data on pesticide residues provide sufficient information, to determine there are no public health issues that require us to circumvent the standard regulatory procedures for generating data and assessing risks.

It is clear from the proposed approaches that the members of the SAB Committee on Integrated Exposure Assessment have reviewed, that there are a variety of possible approaches, and that several of the methods may be adaptable to the specific requirements of pesticide exposure assessment under FQPA.

Many of the components of FQPA, highlight the need to consider additional factors in the evaluation of pesticide uses on foods, including cumulative assessments for compounds that produce their toxic effects through similar mechanisms. While the need to consider additional factors has been noted, potential methods for conducting such assessments are in the early stages of development. Not only are they not fully developed, they have not been tested nor have they been validated. The appropriateness of one approach versus another approach is currently the subject of heated debate in scientific forums. It is clear from the presentations made to the Science Advisory Board and earlier this spring to the EPA Science Advisory Panel that apparently small differences assumptions regarding which data are used can make orders of magnitude difference in estimates of exposure and risk. Therefore, each assumption needs to be carefully examined to understand its impact on the overall assessment. Where an assumption makes a significant difference in the outcome of the exposure assessment, the impact of different assumptions must be examined. The most appropriate assumptions are based on sound scientific principles.

Data assumptions must be relevant to current agricultural and consumer practices. They should not be hypothetical "worst case" situations. They should be based on good data, generated under EPA guidelines.

Although there are a wealth of data about pesticides, including toxicity studies and food residue levels, FQPA requires new information. The new information cannot be obtained with existing methodology. FQPA requires a great deal of creative design and thought to develop approaches that will truly answer the questions that were posed by FQPA. For example, FQPA requires the assessment of simultaneous intake of a number of residues in a single meal or in a single piece of fruit or vegetable. This type of assessment is most accurate if residues are measured in foods "as consumed." Typically a marketbasket study provides the best data. Although we have conducted market basket studies, as has the FDA, we have used methods that were designed to predict our intake over a long period of time and to look at the intake of individual chemicals. We now must modify the existing study designs to allow us to quantify residues in individual pieces of food and to allow us to determine the presence of more than one pesticide in that food. These changes raise new statistical design and sampling questions and pose a host of analytical challenges. There are no existing guidelines for such studies. Rushing to collect such data without validation of the methods can generate faulty data that, in my opinion, will be worse than no data at all.

The scientific issues facing EPA in the implementation of FQPA are at the research stage rather than the regulatory policy implementation stage. I urge you to urge EPA to proceed as they have in other areas where the science has advanced or where new concerns have been raised. EPA should conduct a through and systematic evaluation of existing methodology to determine the most appropriate approach to generate the assessments that are required under FQPA. Once those methods have been identified, they must be validated. All methods must be validated before they are used as the basis for government regulatory policy.

Further more, should EPA determine that new studies are required to provide data needed to comply with FQPA, guidelines for those studies must be developed and adopted. Otherwise, regulatory decisions will not be scientifically defensible.

I believe the existing data provide sufficient information to assure you that there are no existing public health issues that require us to circumvent the standard regulatory procedures for generating data and assessing risks. FQPA identified new areas to be considered in evaluating the safety of pesticides; now it is EPA’s turn to develop and validate the methodology and guidelines for new data collection to permit scientifically based safety assessments. Wherever possible, assessments should be made on the basis of data not assumptions – even if that requires a delay to permit the design of the correct study methods to answer the question and the collection of the pertinent information.

Thank you.