(A) Acute Dietary Exposure
(B) Report on pesticide residue intake studies at the international and national level based on guidelines for predicting dietary intake of pesticide residues
(C) Reports on the Revision of Regional Diets and Information on Processing
Acute Dietary Exposure Assessment[4]
20. The WHO Representative reported on the development of databases for acute exposure assessment. In response to two circular letters[5], Australia, France, Japan, The Netherlands, the UK and the USA had provided information on large portion food consumption for their populations. This was defined as the 97.5th percentile consumption (for consumers only) of the food for the general population (all ages) and for children (ages 6 and under). Although the data were limited to only a few countries and some of the data did not exactly conform to the ages for the defined populations, the 1999 JMPR endorsed the use of the highest 97.5 percentile consumption level in the calculation of the IESTI.
21. Using the data provided, WHO (GEMS/Food) has compiled a global database of the highest reported 97.5th percentile consumption for the two groups. In addition, a database on median/mean commodity unit weights was prepared based on information supplied by France, Japan, the UK and the USA. These databases were used by the 1999 JMPR in calculating the IESTI for pesticide residues for which acute RfDs were established and for those for which a review of acute toxicity was recommended.
22. The Committee was provided with copies of the databases as well as details of the body weights and ages of the populations for which food consumption data was provided. A number of discrepancies in the databases were noted and the WHO Representative asked that all such comments be provided to GEMS/Food. The most current databases could be obtained from the WHO web site (who.int/fsf) or on request to the WHO Food Safety Programme (Attn: GEMS/Food Manager).
23. The Committee noted that the acute hazard exposure assessment methodology had evolved rapidly since the 1997 Geneva Consultation[6] and was still evolving. The report of the 1999 JMPR provided a summary of the current methodology, including the rationale for significant changes adopted by the JMPR (Sections 2.4 and 3). These changes include the use of the highest median residue in supervised trials instead of the MRL in cases where a composite sample reflecting the residue level in a meal-sized portion of the commodity; and the use of default variability factor of 7 instead of 10 for medium size units in cases where the meal-sized portion might have higher residue than the composite.
24. The Committee had some exchange of views regarding variability factors. Several delegations expressed views that they were in favour of using variability factors based on actual residue trial data rather than using default factors such as 7 or 5 as stated in Section 3 of the 1999 JMPR Report. It was noted that the current methodology already proposed using measured variability, when sufficient data was available.
25. Some delegations also mentioned that the use of probabilistic studies[7] would be prevalent or important in the future. The Delegation of The Netherlands stated that point estimate calculations could result in an overestimation of risks involved and presented the outcome of their study in which the Monte Carlo simulation at the 99.99th percentile of the range of consumer exposures resulted in a lower intake estimate than that calculated with the point estimate for the 97.5th percentile of the consumption of the eaters only and highest residues found. The Committee, however, deferred consideration on this subject to future sessions.
26. The Observer from GCPF noted that acute reference doses were being established on the basis of sub-acute, or other, toxicological studies, because appropriate endpoints were not determined in the protocol for acute studies. A new protocol prepared by the ECPA Toxicology Experts Group was made available to the Session.
Risk Management Options[8]
27. The Chairperson of the Committee introduced CX/PR 00/3. He explained the recommendations of two expert consultations on dietary exposure assessment, elements of acute dietary exposure assessment (see paras 20-24 above), establishment of acute reference doses by JMPR, the consideration of the acute dietary exposure assessment methodology and estimation of IESTIs by the 1999 JMPR; and presented proposals and recommendations for discussion. He reminded the Committee of its decisions made at the 29th Session concerning the procedures in relation to chronic exposure assessment and stressed that the Committee should base its decision on international dietary exposure assessment.
28. Recognizing the urgent need for internationally agreed methodology, the Committee agreed to the following preliminary measures which would require further development:
- to endorse at an interim basis the acute risk assessment methodology as refined by the 1999 JMPR and to implement the acute risk assessment to the extent possible when elaborating Codex MRLs;29. The Committee noted that while it was ideal to estimate IESTIs for all MRLs including adopted Codex MRLs, it was considered only feasible for new MRLs and those MRLs under periodic review.- to request the ad hoc Working Group on Priorities to take potential acute intake concerns into consideration when setting priorities for periodic review;
- to request JMPR:
- to continue to refine the methodology on acute dietary risk assessment;
- to further develop general guidance on procedures for estimating an acute reference dose taking into consideration approaches currently used or developed by Governments and other interested parties;
- to develop criteria to assist in creating a list of commodities for which an acute risk assessment is not necessary;
- to evaluate toxicology and residue data of a given compound in a single meeting; and
- to publish the corrected 1999 IESTI calculation (see para. 15);
- to seek comments/information from Governments by a circular letter on:
- the acute risk assessment methodology refined by the 1999 JMPR. Comments should be sent to the FAO Joint Secretary to the JMPR by the end of July 2000 for consideration by the 2000 JMPR;
- whether and how they performed acute dietary risk assessment; and
- consumption data (large portion consumption data, median weight of commodity units, body weights and ages of the populations relevant to the data, and edible percentage of the commodity) to be sent to WHO to improve and expand the existing data bases; and
- to request Governments and other data submitters to generate new data in order to replace the default factors for variability currently used by more realistic factors reflecting the variability of residues in individual commodity units.
30. The Observer from CI stated that guidance for making case-by-case decisions should be developed, for example, whether the commodity is frequently consumed in large amounts, especially in raw or minimally processed forms. She also stated that it would be helpful to request governments to submit additional data at other consumption levels since 97.5th percentile might not be adequate to ensure consumer protection taking into consideration the small number of countries that had submitted data. The Observers from the EC and CI stated that MRLs should not be advanced beyond Step 7 unless there was clear evidence that no acute intake concerns existed.
31. On a proposal to request an expert consultation, the Committee was of the opinion that it was premature to make decision on it pending submission of information which might enable the Committee to identify issues to be considered by such an expert consultation.
32. The Committee was informed that the 1999 JMPR had performed relevant chronic dietary intake assessments for pesticide residues considered, except for ethoxyquin (existing CXL recommended for withdrawal by the 1999 JMPR)[9]. Only the best possible estimates for diazinon and propargite exceeded their corresponding ADIs for one or more regional diets. However, more refined intake estimates were likely to resolve any intake concerns.
33. In addition, the JMPR had calculated IESTIs for pesticide residues for which acute RfDs had been established (dinocap, fenamiphos and methiocarb) and for those for which a review of acute toxicity had been recommended (carbofuran, carbosulfan, diazinon, ethephon, fenpropimorph, fenpyroximate, folpet, malathion, phosalone and tebufenozide)[10]. According to the IESTIs, residues of dinocap in tomato and methiocarb in strawberry would not pose potential acute intake concerns. However, the IESTI of fenamiphos, for some commodities, substantially exceeded the acute RfD.
Revision of Regional Diets[12]
34. The WHO Representative reported on progress by WHO on the revision of GEMS/Food Regional Diets, particularly on the work in expanding the five GEMS/Food Regional Diets to produce more representative diets.
35. In response to a circular letter[13], comments on the proposed diets were received from Australia, Norway, The Netherlands, South Africa and the USA. There was general support for the use of the cluster analysis methodology in generating the new cluster diets, and no country expressed a request to be assigned to another cluster. Australia and The Netherlands posed several technical questions about the groupings of foods used to generate the clusters.
36. Australia and the USA questioned whether the expansion of the five existing GEMS/Food Regional Diets was cost-effective and whether this would best serve the goals of the CCPR. Regarding the cost-effectiveness of having 13 diets, the WHO Representative estimated that completion of the full diets for all 13 consumption clusters would cost at least US$ 100 000 because of the large amount of missing data for many of the clusters, and suggested that it might be appropriate to consider a reduction in the number of cluster diets from 13 to 9 without compromising the scientific basis of the diets.
37. In response to comments from Brazil, The Netherlands and the USA, the WHO Representative noted that development of the consumption cluster diets as well as the 5 GEMS/Food Regional Diets relies on the FAO Food Balance Sheet data. While a few countries possess more accurate data from food consumption surveys, the use of the Food Balance Sheet data provides a common basis for merging data into clusters or regions. While the merging process involves some averaging of consumption, Food Balance Sheet data are thought to overestimate true consumption of the average consumer by about 15% which would tend to protect population subgroups with higher consumption. In reviewing the proposed diets, countries were encouraged to compare their consumption patterns with those of the proposed diets to assure protection for their overall population.
38. Regarding the pilot testing of the GEMS/Food Consumption Cluster Diets, the Committee requested GEMS/Food to develop some examples of the impact on exposure assessments if the current GEMS/Food European-type diet was replaced by the proposed cluster diets. In addition, the Committee requested GEMS/Food to provide an estimate of the total consumption of food in order to assess potential differences among the cluster diets.
Processing studies[14]
39. To assist in the interpretation of processing studies submitted to JMPR, GEMS/Food developed a questionnaire to obtain more detailed and accurate information on food processing practices in different countries. The questionnaire had been presented to the Committee at its last session where it had been decided that, the questionnaire should be sent to governments in a circular letter for response[15].
40. In response to the circular letter[16], comments and information were received from Japan, Republic of Korea, The Netherlands, South Africa, Thailand, the USA and GCPF. Only Thailand fully completed the questionnaire. Partial responses were received from Japan and the USA, particularly in reference to the process flow diagrams for commonly processed commodities. Other countries indicated that they intended to complete the questionnaire.
41. The USA and GCPF requested further information on the use of such processing data by JMPR, especially in the light of the current data requirements of JMPR concerning the fate of residues during processing. The current JMPR guidelines for processing studies generally apply to only significant residues, i.e., those above 0.1 mg/kg and are not intended to impose new testing requirements. Speaking on behalf of JMPR, Dr U. Banasiak stressed that JMPR had considered the questionnaire as a source of information on processing methods and not as the basis for developing new testing requirements by JMPR or default criteria in the evaluation of processing studies.
42. The Delegations of Japan and the USA commented on the comprehensive nature of the questionnaire. Recalling that the Committee had requested GEMS/Food to include all commodities for which Codex MRLs had been established or were being elaborated, the questionnaire was expanded to be comprehensive. However, in the completed questionnaire from Thailand, many of the entries indicated that the food was not consumed or was only consumed in small amounts.
43. Given the short time to reply to the circular letter and that a number of countries indicated their intent to respond to the questionnaire, the Committee decided to issue a follow up circular letter. The Committee also agreed to forward the questionnaire to JMPR to obtain their comment on the use of the resulting food processing information.
