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4 The Scenarios and the Results INTRODUCTION This chapter describes the results of four scenarios, or policy con- structs, that represent plausible strategies for the EPA to follow when reregistering oncogenic pesticides that are known or suspected to leave residues in raw or processed foods. The consequences of applying each of these scenarios to all existing tolerances are expressed as changes in estimated dietary risk and pesticide use from the committee's baseline (see Chapter 3~. It should be kept in mind that this baseline consists of the estimated dietary oncogenic risk derived from only 28 of the 53 compounds identified by the EPA as oncogenic. The scenarios were developed to estimate the relative impacts on human health and on pesticide use of alternative approaches to controlling dietary oncogenic risk. Each scenario falls within an interpretation of section 409 of the Food, Drug and Cosmetic (FDC) Act. The committee emphasizes, however, that it does not endorse any of the scenarios, nor was it asked to offer any opinion on the compatibility of any of these scenarios with current law or interpretation. These scenarios are theoretical policy constructs. As such, they differ in important ways from the policy options the EPA might follow. First, all the estimated changes in risk and pesticide use assume that all pesticides and tolerances are brought immediately into compliance with the risk levels and criteria articulated in each scenario and that no other criteria influence EPA decision making. In practice, the EPA regulates one 100
THE SCENARIOS AND THE RESULTS ~0~ pesticide at a time and with current resources carries out between 10 and 20 reviews of major active ingredients each year. At its current level of activity, the EPA would need perhaps a decade to bring the 150 most widely used pesticides applied to foods into compliance with any single policy. As reported in Chapter 3, however, virtually all pesticides that pose sizable oncogenic risks are scheduled for regulatory review in the next few years. Any new policy the EPA chooses can have a major impact by either reducing or maintaining existing risk in the next two to five years. The projected effects of the scenarios are based on the committee's estimates of dietary risks and pesticide use. Although the committee used EPA data and methods, it had limited resources to analyze pesticide risks and benefits. In carrying out actual regulatory reviews, the EPA assesses a much larger body of scientific data with a much more complicated set of tools and criteria. In particular, the EPA generally uses a weight-of-the- evidence approach in estimating all risks posed by pesticides, not just dietary or oncogenic risks. At each step in the risk assessment process, the EPA considers whether other data and knowledge about a pesticide should alter either a quantitative estimate or the confidence placed in a given calculation. For some chemicals, the agency's concern about the risks is lessened after review of further data. For other chemicals, the EPA's concern is reinforced or heightened. In spite of these limitations, the committee believes the results in this chapter show what could happen after the EPA chooses a policy for complying with the Delaney Clause in the tolerance-setting and regulatory review processes. The results indicate the impact of the Delaney Clause on currently registered pesticides. Future impacts are not projected. Within each scenario, impacts are analyzed at several levels and from alternate points of reference. First, impacts on risk reduction and changes in use patterns are estimated for the 53 pesticides identified by the EPA as oncogens, and then for the herbicides, insecticides, and fungicides included in these 53 compounds. Results approximate the distribution of existing dietary risk and pesticide uses that might be eliminated under policies corresponding to the various scenarios. A second level of analysis focuses on individual pesticides. This chapter examines the impacts of each scenario on the dietary risks and crop uses associated with all the registered uses of a given pesticide. Analyses of individual pesticides are useful because the EPA routinely focuses on the risks of individual active ingredients when deciding how to respond to tolerance petitions and registrations. This perspective is also important to manufacturers and users who are concerned about the continued commercial viability of a pesticide. Last, changes in dietary risks and pesticide use patterns on a crop-by-
102 REGULATING PESTICIDES IN FOOD crop basis are explored. The crops analyzed in-depth were chosen with the help of EPA officials. Each of these crops is commonly processed into other foods in which the EPA has found or suspects concentrated residues. Consequently, existing and future tolerances for oncogenic pesticides in these crops may need to be brought into compliance with the Delaney Clause. Selection of Pesticide-Crop Combinations Because of the time required to gather data on pesticide use and expenditures, only a limited number of crop-level analyses were under- taken. The committee purposely selected crop-pesticide combinations that might present the EPA with difficult decisions regarding application of the Delaney Clause. Crops were chosen based on dietary consumption, economic importance, the volume and value of pesticides currently used on the crop, the availability of alternative pesticide and pest control methods, and the likelihood of concentrated residues in processed foods. On the basis of these criteria, eight crop-pesticide combinations were selected for detailed analysis: · Corn and soybean herbicides; · Cotton insecticides; and · Apple, grape, peanut, potato, and tomato fungicides. These eight combinations account for about 35 percent of total estimated dietary oncogenic risk. ANALYTICAL METHODS Dietary Risk Crop-level analyses in this chapter use a different method for assessing dietary risk than the one used in Chapter 3. In Chapter 3, estimates of dietary risk were based on the assumption that 100 percent of all acres of every crop were treated with each pesticide having tolerances for that crop. The crop-level analyses presented here, however, take account of the actual percentage of planted acres that were treated with each oncogenic pesticide. Estimated risk at the crop level is derived by multiplying the total estimated crop risk by the average percentage of crop acres that were actually treated with each oncogenic pesticide during three of the past five years (not including 1983 for commodity support crops due to acreage reduction under the Payment-in-Kind program). The committee recognizes that adjusting risk estimates by the percentage of acres treated may incorrectly reduce estimated risk to individuals in
THE SCENARIOS AND THE RESULTS 103 regions where a higher percentage of a given crop contains residues of a certain pesticide. On the other hand, this method generally gives a more accurate estimate of risk faced by a population than the method discussed in Chapter 3. The committee adjusted crop-level risk by the percentage of acres treated to calculate the impact of the scenarios on current patterns of pesticide use and to estimate changes in risk based on subsequent pesticide use patterns. It is important to understand that all calculations of dietary risk reduction at the crop level are from risk estimates that take into account the percentage of acres treated. (This adjustment in risk estimates is not used in Chapter 3 or in any but the crop-level analyses in Chapter 4. Information was not available on the percentage of acres treated for all crops with pesticide tolerances.) Pesticide Use In the context of the crop-level analyses, determining the effect of tolerance revocation on the total acre treatments and expenditures associated with oncogenic active ingredients is also possible. Data on acre treatments and expenditures are used as proxy indicators of the benefits of pesticide use. The committee selected these proxies on the assumption that the amount farmers spend on and use a pesticide reflects the gross benefits they receive from the use of that pesticide. The committee is aware that in most situations these proxies do not account for the substitution of pest control methods. Nonetheless, with the available data and time, the committee could identify no more realistic way for approx- imating changes in benefits. DESCRIPTION OF THE SCENARIOS AND RESULTS Four policy scenarios are analyzed. Each contains a distinct set of criteria governing the establishment and evaluation of tolerances for residues of pesticides considered to pose an oncogenic hazard. The scenarios fall along a policy continuum. At one extreme, scenario 1 is strict and aggressive in eliminating all dietary residues of known or suspected oncogenic pesticides. At the other extreme, under scenario 4, most existing tolerances for oncogenic pesticides would fall within an "acceptable" range of risk. The impact of these scenarios on active ingredients not yet registered or on new tolerances sought for active ingredients currently registered is not estimated. The focus here is on oncogenic pesticides currently registered for use on food crops. A description of these scenarios is presented in Table 4-1.
104 REGULATING PESTICIDES IN FOOD TABLE 4-1 Key Features of the Four Scenarios Exam Committee ined by the Scenario Tolerances 1 2 4 Risk Standard Section 408 Zero Risk/benefit risk Section 409 Zero risk 10-6 risk trigger for each crop, processed and raw form combined; no consideration of benefits Zero risk for processed foods (tied to parent raw com- modities) See above Consistent Treatment of Section 408 and Section 409 Tolerances Yes No Yes No Risk/benefit for raw foods with no processed form 0-6 risk trigger for processed foods (tied to parent raw commodities); no consideration of benefits Scenario 1 Scenario 1 applies a zero-risk standard to oncogenic residues in or on all raw and processed foods. The impact is simplewhenever the agency determines that a pesticide poses an oncogenic risk, all existing food tolerances for the pesticide are revoked. Under this scenario, no distinction is made between residues in or on raw or processed foods. Hence, neither the agency nor the pesticide registrants would have to determine whether a pesticide concentrated in processed foods. Moreover, because any finding of oncogenicity would trigger tolerance revocation, there would be no need to quantify oncogenic risk. In essence, this scenario applies the historic understand- ing of the Delaney Clause to residues in processed foods and extends it to residues in or on raw commodities. RESULTS Scenario 1 would eliminate all dietary exposure to pesticides that have caused an oncogenic response in test animals. The magnitude of dietary risk reduction accomplished would depend on how risks were estimated. For any method of estimating risk, 100 percent of it would be eliminated. (See Table 4-2 for risk reduction based on the committee's baseline risk estimates developed in Chapter 3.)
THE SCENARIOS AND THE RESULTS 105 TABLE 4-2 Scenario 1 Reduction in Estimated Risk Risk .~.~.` Total Type of Pesticide Reduction Percentagea Expenditures (%)b Fungicides 3.46 x 10-3 1OO 90 Herbicides 1.58 x 10-3 1OO 38 Insecticides 8.00 x 10-4 1OO 40 All oncogenic fungicides, 5.84 x 10-3 1ooc 45 herbicides, and insecticides NOTE: Risk estimates are derived from the 28 herbicides, insecticides, and fungicides constituting the committee's total dietary risk estimate. They are derived using EPA data and methods described on pages 50 66 and in Appendix B. aThese figures express the percentage of risk reduction for herbicides, insecticides, or fungicides. bThese figures express the percentage of total expenditures for all herbicides, insecticides, or fungicides. CThis figure expresses the percentage of risk reduction for herbicides, insecticides, and fungicides. This figure expresses the percentage of total expenditures for all herbicides, insecticides, and fungicides. Food-use tolerances would be revoked for all 53 pesticide active ingredients that EPA has determined, conclusively or preliminarily, to be oncogens. The number and distribution of tolerances revoked and crops affected are reported in Table 4-3. A total of 3,769 raw and processed food forms with approved tolerances or assumed residues in the Tolerance Assessment System (TAS) would be affected, which is about 25 percent of the total number. Almost 200 crops would lose tolerances, which equals about 95 percent of all crops with pesticide tolerances. The fungicides would be particularly affected; 44 percent of all existing fungicide tolerances would be revoked. As shown in Table 4-3, herbicides and insecticides are less severely affected. Crop-Level Analysis As shown in Table 4-4, the impact of scenario 1 on individual crops varies greatly. Tolerances associated with 18 percent of all grape fungicide acre treatments and 91 percent of all potato fungicide acre treatments would be revoked. Measured by the percentage of total expenditures associated with lost tolerances, the range is from 8 percent for grape fungicides to 83 percent for peanut fungicides. Another significant difference for the eight crops examined is the number of registered pesticides remaining as viable substitutes. The key indicator is the percentage of acre treatments eliminated when oncogenic pesticides are barred from use on food crops. The greater the percentage
106 REGULATING PESTICIDES IN FOOD of acre treatments affected, the greater the presumed impact on the "benefits" of pesticide use. A more accurate estimate of scenario l's impact on these crops can be gained by judging the ease of switching from oncogenic to non-oncogenic pesticides. A crude indication of substitution is the number of registered alternatives available to replace oncogenic pesticides. It is generally more difficult to find substitutes for fungicides than for herbicides and insecti- cides. Under scenario 1, from one-third to one-half of all fungicides with tolerances for the crops discussed would be lost. For insecticides and herbicides, the tolerances lost are always less, ranging from 8 to 20 percent. Actual substitutability, however, must be considered on a case-by-case basis; some herbicides and insecticides may be effective on only a small percentage of weed and insect species. This analysis suggests clearly that crops heavily dependent on fungi- cides would suffer the most severe consequences under scenario 1. (This observation will be documented further in Chapter 5.) Administratively, scenario 1 would be simple to implement. The only issue of possible contention an issue common to all scenarios is whether a given pesticide is or is not an oncogen. Once that judgment is made, the implications of scenario 1 are clear: all food tolerances are revoked. Traditional risk/benefit assessments following the approaches in Chapter 2 would be undertaken for non-oncogenic pesticides. It is possible, of course, that other public health or environmental risks of such pesticides TABLE 4-3 Scenario 1- Effect on Active Ingredients, Tolerances, and Crops Effect on Active Tolerances and Type of Ingredients Residue Estimates Crops Losing Pesticide (number) (number/%)a Tolerances Herbicides 17 1,295/26 172 Insecticides 19 1,222/17 152 Fungicides 14 1,111/44 137 Other 3 141 NA All oncogens 53 3,769125b 186 NOTE: The effect on tolerances and crops are for the 53 active ingredients the EPA identified as oncogenic. The tolerances and crops associated with the 28 active ingredients where risk estimates were available to the committee are used as a basis for comparison in tables describing the results of scenarios 3 and 4. aThese figures express the percentage of all herbicide, insecticide, or fungicide tolerances and residue estimates in the TAS. bThis figure expresses the percentage of all tolerances and residue estimates in the TAS.
THE SCENARIOS AND THE RESULTS 107 TABLE 4-4 Impacts of Scenario 1 on Major Crop Uses for Registered Pesticides Number of Active Ingredients Estimated Percent Reduction in Acre Percent With Losing Crop Risk Treatments Expenditures Crop Tolerances Tolerances (number/%) Lost Affected Fungicides Apples 21 10 4.28 x 10-5/100 59 53 Grapes 15 7 5.56 x 10-6/100 18 8 Peanuts 14 9 3.83 x 10-7/100 86 83 Potatoes 15 10 6.47 x 10-5/100 91 80 Tomatoes 20 11 8.28 x 10-5/100 50 51 Herbicides Corn 39 8 1.31 x 10-6/100 39 40 Soybeans 40 11 1.59 x 10-5/100 67 58 I n s e cd c i d es Cotton 45 9 1.29 x 10-5/100 80 60 NOTE: These risk estimates are derived using EPA data and methods described on pages 50 66 and in Appendix B. Risk estimates in this table are adjusted (multiplied) by the percentage of acres treated. might outweigh the benefits, leading to some regulatory action. That outcome is equally likely under existing law, however. Scenario 2 This scenario applies a zero-risk standard to all oncogenic pesticide residues in processed foods. No detectable residue of an oncogenic pesticide in a processed food would be allowed. Because the mere presence of a residue in a processed food would trigger tolerance revocation under this scenario, the percentage of tolerances and crops affected is expressed as a percentage of tolerances and crop uses for all 53 oncogenic compounds. Reductions in risk, as with all scenarios, are derived from the 28 pesticides for which risk estimates were available to the committee. Because concentration of residues is not required to trigger tolerance revocation under this scenario, it is stricter or more risk averse than current law. In applying the zero-risk standard to residues in processed foods under scenario 2, there is no consideration of benefits. For the purpose of calculating risk reduction, this scenario assumes there is no practical way to separate the portions of a crop grown only for fresh markets from those destined for processing. Thus, scenario 2 requires revocation of section 408 and section 409 tolerances to enforce the zero-risk standard in processed foods. The EPA has taken a similar
~ 08 REG ULA TING PES TI CIDES IN FOOD approach in the past, routinely linking approval of section 408 raw food and section 409 processed-food tolerances. The only exceptions to this practice occur when there is a practical way to ensure that a crop is marketed exclusively in its fresh or raw form. This rarely occurs, however. (See the permethrin case study in Chapter 3 and Appendix C.) Scenario 2 differs from scenario 1 in its application to crops such as lettuce, other vegetables, some fruits, and all meat, poultry, and dairy products that have no processed form under current EPA guidelines. These foods require only section 408 tolerances. In contrast, under scenario 1, residues of all oncogenic pesticides on all foods are disal- lowed. Oncogenic residues are disallowed in scenarios 1 and 2 for all crops with recognized processed forms. RESULTS Scenario 2 would reduce total estimated dietary oncogenic risk by about 55 percent. Risk is reduced unevenly among insecticides, herbi- cides, and fungicides, however. More than 70 percent of all risk from fungicides would be eliminated, compared with only about 26 percent of all insecticide risk and about 36 percent of herbicide risk (see Table 4-51. In contrast, Table 4-6 shows that the percentage of all oncogenic pesticide tolerances and residue estimates affected is quite uniform, ranging from 56 percent for fungicides to 50 percent for insecticides. Section 408 tolerances associated with 45 percent of all oncogenic risk would remain unaffected under scenario 2. This share of the total estimated risk is from foods with no currently recognized processed forms, including vegetables, fruits, eggs, and all meat and dairy products. TABLE 4-5 Scenario 2 Reduction in Estimated Risk Risk Type of Pesticide Reduction Estimated (%)a Fungicides 2.45 x 10-3 70.7 Herbicides 5.75 x 10-4 36.4 Insecticides 2.12 x 10-4 26.5 All oncogenic fungicides, 3.23 x 10-3 55.4b herbicides, and insecticides NOTE: Risk reduction is measured from the 28 herbicides, insecticides, and fungicides constituting the committee's total dietary risk estimate. These risk estimates are derived using EPA data and methods described on pages 50-66 and in Appendix B. aThese figures express the percentage of risk reduction for herbicides, insecticides, or fungicides. bThis figure expresses the percentage of risk reduction for herbicides, insecticides, and fungicides.
THE SCENARIOS AND THE RESULTS -109 TABLE 4-6 Scenario 2 Effect on Active Ingredients, Tolerances, and Crops Effect on Active Tolerances and Ingredients Residue Estimates Crops Type of Pesticide (number) (number/%)a (number/%)b Fungicides 11 627/56 27/20 Insecticides 6 648/53 25/16 Herbicides 9 659/50 34/20 All oncogenic fungicides, 26 1,934/5 1c herbicides, and insecticides 38/20a' aThese figures express the percentage of all oncogenic herbicide, insecticide, or fungicide tolerances and TAS residue estimates. bThese figures express the percentage of all crops treated with oncogenic herbicides, insecticides, or fungicides. CThis figure expresses the percentage of all oncogenic herbicide, insecticide, and fungicide tolerances and TAS residue estimates. a'This figure expresses the percentage of all crops treated with oncogenic herbicides, insecticides, and fungicides. Under scenario 2, these uses would be reviewed in the traditional fashion, which could lead to some risk reduction beyond the assured 55 percent risk reduction under this scenario. The committee is unable to project the outcome of these individual risk/benefit decisions in this and all other scenarios. The reader can gain some perspective on the crops and foods that lack processed forms and hence are not under any circumstances affected by the Delaney Clause from Table 3-11 in the previous chapter. From the standpoint of agricultural producers, scenario 2 has a rela- tively narrow effect. Not more than one in five crops would lose tolerances, although S 1 percent of all tolerances for oncogenic herbicides, insecticides, and fungicides would be lost. Some crops that would lose tolerances are major commodities. Ejects on Individual Active Ingredients Dietary risk reduction under this scenario is efficient in that a SS percent reduction in risk is achieved through tolerance revocations affecting only about 20 percent of all crops for which these oncogenic compounds are registered (see Table 4-61. For example, with the widely used fungicide benomyl, a 93 percent reduction in dietary risk would be achieved through tolerance revocations affecting only 17 crops with processed forms, or 17 percent of the 101 foods (including meats) for which benomyl has tolerances. For another major fungicide, captan, revocations on 19 crops with processed forms, or 25 percent of all captan registrations, account for a 71 percent reduction in
~ ~ 0 REG UrA TING PES TI CIDES IN FOOD dietary oncogenic risk from this pesticide. For a major herbicide, alachlor, a 50 percent reduction in risk is attained by revoking tolerances for only four crops, or 16 percent of all alachlor tolerances. The degree of risk reduction under this scenario, however, depends greatly on the crop on which a pesticide is used. The impact on the crop then stems from whether and to what extent it is processed. Under this scenario, residues in raw agricultural products are approved under a different standard than residues in processed foods. These different standards account for the fact that some crops and types of pesticides are preferentially targeted. For example, dietary risk from benomyl is re- duced by 93 percent with a corresponding loss of benefits. Dietary risk from linuron and maneb, however, is reduced by only 36 and 43 percent, respectively. This inconsistency reveals the significance of judgments on which crops are considered not processed. Currently, many crops, such as raspberries and other small fruits, are in this category even though jams, jellies, candies, and other foodstuffs made from such fruits are clearly processed- food forms. The need to redefine the processed and not processed categories could put considerable administrative and resource strains on the agency. Residues in animal feeds and food products pose particular problems. Any policy with significantly different definitions of processed and not processed food could lead to markedly different regulatory outcomes. Crop-Level Impacts Impacts on seven of the eight crops examined under scenario 2 are identical to scenario 1. All risk is eliminated and all tolerances are revoked (see Table 4-7) except for peanut fungicides. This result occurs for all the crops studied except peanuts because TAS assumes no processed peanut food forms for the 53 oncogens examined. This anomaly is a result of the TAS tolerance expansion process and does not imply that residues will not be present or that peanuts have no processed forms. Peanut butter and peanut oil are clearly processed-food forms. The TAS contains peanut oil tolerances for other pesticides. This example highlights the critical relationship between the definition of a processed food and the application of the Delaney Clause to food tolerances. As pointed out above, when a zero-risk standard precludes establishment of a processed-food tolerance, this generally means that tolerances for the parent raw commodity must also be revoked. Scenario 3 Scenario 3 applies a 1 in 1 million (1 x 10-6) risk standard to section 408 and section 409 tolerances, that is, to all processed and raw foods. Dietary risk estimates are calculated using the sum of TAS residue estimates for
THE SCENARIOS AND THE RESULTS 1 1 1 TABLE 4-7 Impacts of Scenario 2 on Major Crop Uses for Registered Pesticides Number of Active Ingredients- Estimated Percent Reduction in Acre Percent With Losing Crop Risk Treatments Expenditures Crop Tolerances Tolerances (number/%) Lost Affected Fungicides Apples 21 10 4.28 x 10-5/100 59 53 Grapes 15 7 5.56 x 10-6/100 18 8 Peanuts 14 No impact No impact No impact No impact Potatoes 15 10 6.47 x 10-5/100 91 80 Tomatoes 20 11 8.28 x 10-5/100 50 51 Herbicides Corn 39 8 1.31 x 10-6/100 39 40 Soybeans 40 11 1.59 x 10-5/100 67 58 Insecticides Cotton 45 9 1.29 x 10-5/100 80 60 NOTE: These risk estimates are derived using EPA data and methods described on pages 50 66 and in Appendix B. Risk estimates in this table are adjusted (multiplied) by the percentage of acres treated. each use of a pesticide on raw and processed forms of a given crop. When the total dietary risk from the residues of any pesticide found on the raw and processed forms of a crop exceeds 10-6, all tolerances for that pesticide on that crop would be revoked or denied. There would be no consideration of benefits once risk went above this level. The use would be automatically disapproved. Because this scenario is based on quanti- tative levels of risk, it could only be applied to the 28 compounds that comprise the committee's estimate of dietary oncogenic risk. An important feature of this scenario is that dietary risk is calculated at the crop level, as opposed to current EPA practice in which dietary risk is calculated for an active ingredient across all of its uses. In this scenario, for example, exposure to an oncogenic pesticide on fresh tomatoes is added to the exposure to these residues in all processed tomato products in determining whether the 10-6 risk trigger is met for that crop use. When the trigger is exceeded for tomatoes, there would be no consideration of benefits from that pesticide's use on tomatoes. Tolerances for these uses would be revoked. Dietary risks less than 10-6 from a pesticide's use on a crop would be evaluated using standard procedures. This scenario applies the same standard to tolerances for both raw and processed commodities. In contrast to current EPA practice, this sce- nario implies a stricter regulatory stance on section 408 raw agricultural commodity tolerances, particularly those with no associated section 409 tolerances, because benefits are not considered when risks exceed 10-6.
~ ~ 2 REGULA TING PESTICIDES IN FOOD It is less strict, however, than the current zero-risk standard for section 409 processed-food tolerances and their associated section 408 toler- ances; tolerances for processed foods are not prohibited unless risks from the whole crop exceed the 10-6 standard. RESULTS This scenario and scenario 4, below, demonstrate the impact of simple assumptions in the calculation of exposure and how these assumptions affect dietary risk estimates across different food products and crop uses. The most striking result of scenario 3 is that although 98 percent of total estimated dietary risk would be eliminated, only 32 percent of all tolerances for oncogens and 38 percent of all crops would be affected. Scenario 3 would achieve only 2 percent less risk reduction than scenario 1, while revoking 1,500 fewer tolerances for the 28 compounds that constitute the committee's risk estimate (see Tables 4-8 and 4-9~. Scenario 3 is efficient in that it targets crop uses posing dietary risks greater than 10-6 and revokes the associated tolerances, but still leaves untouched nearly 70 percent of all tolerances and nearly two-thirds of all crops (see Table 4-81. For example, 99 percent of all herbicide risk would be eliminated, but only 16 percent of all herbicide tolerances would be revoked. Just 12 percent of all crops treated with oncogenic herbicides would be affected. For fungicides, the percentage and numbers of tolerances and crops affected are higher. Yet, more than 98 percent of dietary risk is eliminated through revocation of 53 percent of fungicide tolerances affecting 42 percent of the 137 crops on which fungicides are used. TABLE 4-8 Scenario 3Reduction in Estimated Risk Risk Type of Pesticide Reduction Percentagea Fungicides 3.41 x 10-3 98.5 Herbicides 1.56 x 10-3 98.9 Insecticides 7.79 x 10-4 97.4 All oncogenic fungicides, 5.75 x 10-3 98.5b herbicides, and insecticides NOTE: Risk reduction is measured from the 28 herbicides, insecticides, and fungicides constituting the committee's total dietary risk estimate. These risk estimates are derived using EPA data and methods described on pages 50-66 and in Appendix B. aThese figures express the percentage of risk reduction for herbicides, insecticides, or fungicides. bThis figure expresses the percentage of risk reduction for herbicides, insecticides, and fungicides.
THE SCENARIOS AND THE RES Ul;TS ~ ~ 3 TABLE 4-9 Scenario 3 Effect on Active Ingredients, Tolerances, and Crops Effect on- Tolerances Active and Residue Ingredients Estimates Crops Type of Pesticide (number) (number/%)a (number/56)b Fungicides 10 502/53 58/42 Insecticides 5 132/21 27/20 Herbicides 7 122/16 20/12 All oncogenic fungicides, 22 756/32C 68138 herbicides, and insecticides aThese figures express the percentage of herbicide, insecticide, or fungicide tolerances and TAS residue estimates for the 28 compounds constituting the committee's total dietary risk estimate. bThese figures express the percentage of crops treated with the herbicides, insecticides, or fungicides for the 28 compounds constituting the committee's total dietary risk estimate. CThis figure expresses the percentage of all herbicide, insecticide, and fungicide toler- ances and TAS residue estimates for the 28 compounds constituting the committee's total dietary risk estimate. This figure expresses the percentage of all crops treated with the 28 compounds constituting the committee's total dietary risk estimate. Impacts on Individual Active Ingredients A notable feature of sce- nario 3 is that it has no impact on certain widely used oncogenic pesticides when the oncogenic risk from any individual crop does not exceed 10-6. For instance, the widely used but weakly oncogenic herbicides glyphos- ate and metolachlor would not experience any tolerance revocations. Under scenario 2, the same herbicides would suffer many tolerance revocations because of the presence of residues in processed foods. Further, for certain compounds, scenario 3 achieves a greater or equal reduction of risk by revoking fewer tolerances than do other scenarios. In the case of the fungicide benomyl, scenario 3 achieves the same percent- age reduction in risk as the next best scenario (2), while affecting 5 percent fewer crops. Crop-Level Impacts The difference between scenario 2 and 3 is particularly striking at the crop level (see Tables 4-7 and 4-104. Whereas scenarios 1 and 2 eliminate all tolerances associated with processed crops, scenario 3 would affect only those crop uses where the combined dietary risk from fresh and processed food residues is greater than 10-6. Scenario 3 is more discriminating.
~14 REGULATING PESTICIDES IN FOOD TABLE 4-10 Impacts of Scenario 3 on Major Crop Uses for Registered Pesticides Number of Active · Estimated Percent Ingred~ents- Reduction in Acre Percent - With Losing Crop Risk Treatments Expenditures Crop Tolerances Tolerances (number/%) Lost Affected Fungicides Apples 21 4 4.21 x 10-5/98 54 46 Grapes 15 1 3.38 x 10-6/70 10 4 Peanuts 14 No impact No impact No impact No impact Potatoes 15 1 4.36 x 10-6/68 31 29 Tomatoes 20 5 8.22 x 10-5/99 49 51 Herbicides Corn 39 2 1.31 x 10-6/99.9 30 27 Soybeans 40 2 1.59 x 10-5/99.9 27 20 Insecticides Cotton 45 1 1.28 x 10-5/99 9 7 NOTE: These risk estimates are derived using EPA data and methods described on pages 5(}66 and in Appendix B. Risk estimates in this table are adjusted (multiplied) by the percentage of acres treated. For some crops, scenario 3 eliminates a high percentage of risk with a modest loss of benefits. For example, dietary risk from cotton insecticides is reduced by 99 percent and grape fungicides by 70 percent, even though in each case tolerances for only one compound are revoked. Each pesticide affected accounts for less than 10 percent of acre treatments and expenditures. These cases suggest that scenario 3 offers a considerable opportunity for sizable risk reductions with relatively modest loss of benefits, at least for some crops. This feature of scenario 3 is not shared by scenario 2. Under scenario 2, six more oncogenic corn herbicides would lose tolerances, resulting in an additional reduction in dietary oncogenic risk from corn of less than one-tenth of 1 percent. Scenario 4 Under scenario 4, tolerances for a crop would be revoked when the risk from all the various processed forms of a particular crop exceeds 10-6. Scenario 4 is conceptually similiar to scenario 2 in one respect; a specified level of risk associated with the processed-food forms of a crop triggers tolerance revocations. The risk level of 10-6 for scenario 4 differs from the zero-risk standard for scenario 2. As in scenario 2, when the specified risk level (10-6) is exceeded by residues in or on the processed portion of the crop, section 408 and section 409 tolerances are revoked.
THE SCENARIOS AND THE RES ULTS ~1 5 RESULTS Scenario 4 reduces the estimated dietary risk derived from 28 herbi- cides, insecticides, and fungicides by about 36 percent. The relatively modest degree of risk reduction in this scenario is partially explained by the fact that all crops with no processed form are exempt. In other words, for raw foods this scenario reflects the current interpretation of section 408. As evident in Table 4-1 1, the ejects of scenario 4 are highly variable. Herbicide risk is reduced by about 11 percent, while nearly 51 percent of fungicide risk is eliminated. There is a high degree of variability from pesticide to pesticide as well. Ten pesticides super no tolerance revoca- tions at all. For the rest, the risk reduction ranges from 6 percent for acephate to 80 percent for benomyl. Scenario 4 affects few crops and a small percentage of all tolerances (Table 4-121. Only 12 percent of all tolerances and 10 percent of all crops treated with oncogenic herbicides, insecticides, and fungicides are af- fected under this scenario. Apples and tomatoes, which are often con- sumed in processed forms, are much more vulnerable under this scenario than other crops. Crop-Level Impacts The results of scenario 4 at the crop level are shown in Table 4-13. Scenarios 3 and 4 have identical effects on cotton and tomato tolerances, yet for all other crops the results are quite different. In scenario 4, current risk from processed corn and potato TABLE 4-11 Scenario ~ Reduction in Estimated Risk Risk Type of Pesticide Reduction Percentagea Fungicides 1.75 x 10-3 50.7 Herbicides 1.76 x 10-4 1l.l Insecticides 1.54 x 10-4 19.2 All oncogenic fungicides, 2.08 x 10-3 35.7b herbicides, and insecticides NOTE: Risk reduction is measured from the 28 herbicides, insecticides, and fungicides constituting the committee's total di- etary risk estimate. These risk estimates are derived using EPA data and methods described on pages 50-66 and in Appendix B. aThese figures express the percentage of risk reduction for herbicides, insecticides, or fungicides. bThese figures express the percentage of risk reduction for herbicides, insecticides, and fungicides.
~16 REGULATING PESTICIDES IN FOOD TABLE 4-12 Scenario Effect on Active Ingredients, Tolerances, and Crops Effect on- Active Ingredients Tolerances Lost Crops Type of Pesticide (number) (number/5~o)a (number/%)b Fungicides 10 207/21 12/9 Herbicides 4 44/6 4/2 Insecticides 4 20/3 4/3 All oncogenic fungicides, 18 271/12C 14/10 herbicides, and insecticides aThese figures express the percentage of herbicide, insecticide, or fungicide tolerances and TAS residue estimates for the 28 compounds constituting the committee's total dietary risk estimate. bThese figures express the percentage of crops treated with the herbicides, insecticides, or fungicides for the 28 compounds constituting the committee's total dietary risk estimate. CThis figure expresses the percentage of all herbicide, insecticide, and fungicide toler- ances and TAS residue estimates for the 28 compounds constituting the committee's total dietary risk estimate. This figure expresses the percentage of all crops treated with the 28 compounds constituting the committee's total dietary risk estimate. TABLE 4-13 Impacts of Scenario 4 on Major Crop Uses for Registered Pesticides Number of Active Ingredients Estimated Percent Reduction in Acre Percent With Tolerances Crop Risk Treatments Expenditures Crop Tolerances Lost (number/%) Lost Affected Fungicides Apples 21 3 4.00 x 10-5/93 49 42 Grapes 15 2 2.40 x 10-5/93 10 4 Peanuts 14 No impact No impact No impact No impact Potatoes 15 No impact No impact No impact No impact Tomatoes 20 5 8.22 x 10-5/99 49 51 Herbicides Corn 39 No impact No impact No impact No impact Soybeans 40 1 1.49 x 10-5/94 9 7 Insecticides Cotton 45 4 1.28 x 10-5/99 9 7 NOTE: These risk estimates are derived using EPA data and methods described on pages 50~6 and in Appendix B. Risk estimates in this table are adjusted (multiplied) by the percentage of acres treated.
THE SCENARIOS AND THE RESULTS 117 products is less than 10-6; therefore no tolerances are revoked. Peanuts are protected because TAS assumes no processed peanut food forms for the 53 oncogens examined. Soybean producers, on the other hand, would lose the use of one compound that accounts for more than 94 percent of the risk from soybean herbicides, but for less than 10 percent of all acre treatments and expenditures. Summary The performance of these scenarios will be discussed in detail in the next chapter. However, several key observations are relevant to all of them. · Uniform treatment of raw and processed food tolerances appears to result in more consistent risk reduction for all pesticides and foods. · A nonzero-risk standard, consistently applied to raw and processed foods, can reduce risk significantly by selecting out high-risk pesticide and food combinations. Any risk standard (including zero risk) applied differently to raw and processed foods cannot achieve such selective risk reduction. · For insecticides and herbicides, risk can be greatly reduced by revoking tolerances for only one or two compounds often those that present high risks and relatively low benefits. For fungicides, however, this is not the case. There are few compounds that present high risk and low benefits. Therefore, actions against one or two compounds often will not result in substantial risk reduction. NOTE 1. Special reviews set for fiscal year 1987 listed. 1986. Pesticide and Toxic Chemical News 14(0ctober):9-10.
