(A) Progress Report by WHO on the Revision of GEMS/Food Regional Diets
(B) Report on Pesticide Residue Intake Studies at International and National Level Based on Revised Guidelines for Predicting Dietary Intake of Pesticide Residues
27. In 1995, the Joint FAO/WHO Consultation on Guidelines for Predicting Dietary Intake of Pesticide Residues in its report (FAO/WHO, 1995) recommended that the existing five GEMS/Food regional/cultural diets be updated and, where appropriate, expanded. This recommendation was subsequently endorsed by the CCPR and JMPR. Based on a paper by Barraj and Petersen, the Joint FAO/WHO Consultation on Food Consumption and Exposure Assessment of Chemicals held in 1997 in Geneva (FAO/WHO, 1997) recommended that a statistical cluster analysis be applied to the 1990-1994 FAO Balance Sheet data[9] to group countries by similarities in dietary patterns and to estimate the consumption of commodity components in those diets.
28. The Representative of WHO reported on the results of the cluster analysis performed by GEMS/Food which identified 13 regional/cultural dietary patterns that could be used for evaluation of dietary exposure to pesticides as well as that of other chemicals in food. The estimated average consumption of the 36 major foods and food groups used in the analysis were presented for each regional/cultural dietary pattern, including identification of countries which had tentatively been assigned to the proposed regional/cultural groupings. Before proceeding to develop the diets further, the WHO Representative requested the Committee to confirm the acceptability or otherwise of the proposed clusters and in particular, the estimated consumption levels for the 36 foods and food groups given in the individual cluster diets.
29. The Committee generally welcomed the revised diets, but most delegations needed more time to consider whether their assigned cluster and diet were appropriate. Some delegations requested more information on the details of the cluster analysis used to generate the diets. The Committee agreed that the proposed clusters and diets, including more specific details on the methodology used in the cluster analysis, should be sent to governments for comment by means of a circular letter. An analysis of the government responses should be reported at the next Session of the Committee.
Predictions of Dietary Intake for Pesticides Evaluated by the 1998 JMPR[10]
30. The 1998 JMPR estimated Supervised Trials Median Residues (STMRs) for all commodities considered in relation to the new compound kresoxim-methyl and for all those undergoing periodic review that were on the agenda of the FAO Panel. However, for compounds evaluated for specific commodities and for those evaluated for toxicity only, both MRLs and STMRs are used as the basis for estimating dietary intake. Theoretical Maximum Daily Intakes (TMDIs) which are based on MRLs and International Estimated Daily Intakes (IEDIs) which are based on STMRs were calculated according to the Revised Guidelines for Predicting Dietary Intake of Pesticide Residues[11]. Dietary intake estimates that are calculated based on a combination of MRLs and STMRs are referred to as Daily Intake Estimates (DIEs).
31. Exposure assessment calculations were performed for pesticides evaluated by the 1997 JMPR except when all MRLs were proposed for withdrawal, as is the case for folpet or when no ADI existed, as is the case for formothion. Of the pesticides considered, 22 had TMDI, DIE or IEDI estimates that were below the ADI for all five regional diets: amitraz, amitrole, benomyl, bentazone, bitertanol, carbendazim, 2,4-D, dicloran, dinocap, diphenylamine, ethoxyquin, glufosinate-ammonium, hexythiazox, kresoxim-methyl, maleic hydrazide, methiocarb, mycobutanil, oxydemeton-methyl, phosmet, procymidone, quintozene, thiophanate methyl. Because of concerns for cumulative toxicity, residues of benomyl, carbendazim and thiophanate-methyl were considered together.
32. The best international intake calculations for dimethoate (IEDI), disulfoton (DIE) and endosulfan (TMDI) exceeded their corresponding ADIs in one or more of the regional diets. Data to calculate more refined exposure estimates for these pesticides, such as STMRs in the cases of disulfoton and endosulfan and processing factors in all three cases, were not available. In addition, factors only available at the national level, such as percent of crop treated and monitoring data, could not be applied at the international level. Consequently, the current dietary intake assessments were likely to overestimate exposure. However, it should be noted that consideration of aggregate exposure and cumulative toxicity may result in a higher exposure estimate but information and/or methodologies were not currently available at the international level to take these factors into account.
33. The Observer from CI expressed concern over the reporting of dietary intake calculations stressing that it should be more balanced by noting that cumulative and aggregated exposure, non-dietary exposure and vulnerability of infants and young children might result in higher exposure. To put the discussion into perspective, the Chairperson reminded the Committee that it had agreed at its 29th Session upon an approach for chronic dietary risk assessment at the international level and its implementation in establishing Codex MRLs. It had considered the agreed approach as a balanced one, safeguarding the health of consumers while not unnecessarily disrupting international trade. The 30th Session of the Committee had considered the issue again and had identified further areas of interest where progress at the international level was expected to be feasible. Specific requests had been referred to the JMPR for consideration in order to further improve the international chronic dietary intake assessment. The Chairperson also indicated that the issue of aggregate exposure was a matter best addressed at the national level and that progress was being made at the national and international level with respect to cumulative exposure estimation. The Committee noted that although the current methodology for chronic dietary exposure was still under development, it was generally accepted by the Committee.
34. Regarding acute hazards, the 1998 JMPR established Acute RfDs for amitraz, dinocap, endosulfan, methiocarb and phosmet. Short-term exposure assessments of acute hazards posed by these pesticides would be undertaken after databases on large portion single day consumption (eaters only) for the general population and children aged 6 and under, and on typical median commodity weights had been established by GEMS/Food. Governments which have such data, but have not yet submitted it to WHO, were requested to do so at their earliest opportunity[12].
Processing studies for improving estimates of dietary intake of pesticide residues[13]
35. The revised Guidelines for Predicting Dietary Intake of Pesticide Residues highlighted the usefulness of processing studies to more accurately estimate pesticide residues in food as consumed. Although some commodities are directly consumed fresh, most commodities will undergo some processing, either commercial or in the home. In order to promote the development of appropriate processing studies which were more representative of the predominant processes used by industry and consumers and to assist in the interpretation of processing studies submitted to the JMPR as well as for other purposes, GEMS/Food had developed a questionnaire[14] to obtain more detailed information on food processing practices in different countries . The questionnaire was tested in cooperation with the International Union of Food Science and Technology (IUFoST) and its member institutions. A preliminary evaluation of the responses received from IUFoST adhering bodies indicated that such processing information would be useful at both the national and international levels .
36. The Committee recognized the usefulness of the questionnaire but noted that the results needed to be interpreted with caution in view of the semi-quantitative basis of the data. In addition, several delegations pointed out a number of improvements that should be considered, including the addition of milk, meat, hops and herbs to the questionnaire. In addition, the questionnaire should be reviewed to assure that all commodities for which Codex MRLs had been established or were being elaborated were included. With these revisions, the Committee decided that the GEMS/Food questionnaire should be sent to governments in a circular letter for response. A report on the results of the survey would be prepared for the next Session.
