Conclusion on the peer review of the pesticide risk assessment of the active substance phosmet

被引:13
作者
机构
[1] EFSA, Parma, Italy
关键词
Phosmet; peer review; risk assessment; pesticide; insecticide; acaricide;
D O I
10.2903/j.efsa.2011.2162
中图分类号
TS2 [食品工业];
学科分类号
0832 ;
摘要
Phosmet is one of the 52 substances of the second stage of the review programme covered by Commission Regulation (EC) No 451/20003, as amended by Commission Regulation (EC) No 1490/20024. This Regulation requires the European Food Safety Authority (EFSA) to organise a peer review of the initial evaluation, i.e. the draft assessment report (DAR), provided by the designated rapporteur Member State and to provide within one year a conclusion on the risk assessment to the European Commission. Spain being the designated rapporteur Member State submitted the DAR on phosmet in accordance with the provisions of Article 8(1) of the amended Regulation (EC) No 451/2000, which was received by the EFSA on 23 August 2004. Following a quality check on the DAR, the peer review was initiated on 03 September 2004 by dispatching the DAR for consultation of the Member States and the sole applicant Margarita Internacional. Subsequently, the comments received on the DAR were examined by the rapporteur Member State and the need for additional data was agreed in an evaluation meeting on 18 May 2005. Remaining issues as well as further data made available by the notifier upon request were evaluated in a series of scientific meetings with Member State experts in September 2005. A final discussion of the outcome of the consultation of experts took place with representatives from the Member States on 6 April 2006 leading to the conclusions set out in the EFSA Conclusion finalised on 12 May 2006 (EFSA Scientific Report (2006) 75). Phosmet was included in Annex I of Directive 91/414 by Commission Directive 2007/25/EC of 23 April, 20075. The entry into force of the Annex I inclusion was 1 October 2007. In March 2010 the European Commission received a request to modify the ADI for phosmet, based on an evaluation of new toxicological data carried out by the United Kingdom following an application from Gowan Comercio Internacional e Servicos. In compliance with the Guidance Document SANCO 10328/2006 rev. 6, the European Commission invited all Member States and EFSA to provide comments on the new evaluation. Following consideration of the comments received, the European Commission requested EFSA to organise a peer review of the new evaluation and to deliver its conclusions on the new proposed ADI for phosmet. The conclusion was reached on the basis of the evaluation of the representative uses as an acaracide and insecticide as proposed by the applicant which comprises tractor-mounted spraying and airblast assisted sprayers in orchards. Application is made to citrus fruit at a rate of 0.5 kg phosmet per hectare, pome fruit at 0.3 kg phosmet per hectare and potatoes at 0.5 kg phosmet per hectare. The representative formulated product for the evaluation was Imidan 50 WP a wettable powder (WP) registered under different trade names in Europe. The representative uses assessed were located in southern Europe only as stated in the application for annex 1 listing. No conclusion on the equivalence of the two sources could be made as some mammalian toxicology data were missing. In the main adequate methods are available to monitor all compounds given in the respective residue definition. The residue definition for water can not be finalised due to outstanding ecotoxicology data. The method for body fluids and tissues is currently only validated for phosmet and as the oxon is in the residue definition further validation data will be required. Only single methods for the determination of residues are available since a multi-residue-method like the German S19 or the Dutch MM1 is not applicable due to the nature of the residues. Limited analytical methods as well as methods and data relating to physical, chemical and technical properties are available to ensure that quality control measurements of the plant protection product are possible. There are some outstanding issues related to the relevant impurities. The toxicological risk assessment is based on the assumption that the studies have been performed with a test material that covers the current technical specification. The absorption is rapid and almost complete, there is no accumulation in tissues and the excretion is mainly via urine. Phosmet is toxic by oral administration and the proposed classification is T, R25. It is non-irritant to skin and eyes and does not cause sensitisation by skin contact. The critical effect after repeated exposure is depression of the plasma, erythrocyte and brain acetylcholinesterase activities. The most sensitive species is the dog. Phosmet is an in vitro but not in vivo genotoxic agent. Increased incidence of liver tumours is observed in mice at the highest dose level (14 mg/kg bw/day), higher than controls but within the same range as historical control data. In a two-generation study with rats, the fertility parameters and the offspring are not directly affected. Phosmet shows no evidence of teratogenicity in rat or rabbits, and no potential to induce delayed neurotoxicity. The Acceptable Daily Intake (ADI) is 0.01 mg/kg bw/day, based on a NOAEL of 1 mg/kg bw/day from the rat multigeneration study, supported by short-term studies in dogs and rats and a long-term study in rats. The Acute Reference Dose (ARfD) is 0.045 mg/kg bw and the Acceptable Operator Exposure Level (AOEL) 0.02 mg/kg bw/day. For the use on potatoes and pomes, exposure estimates according to the German model are below the AOEL for operators wearing personal protective equipment and respiratory protective equipment. In spite of these high protection measures, the operator exposure is above the AOEL during application on citrus fruits. Estimates of worker and bystander exposure are below the AOEL for all the supported uses. Plant metabolism studies with 14C-phosmet in cherries, potatoes and corn are available covering the representative uses. A common metabolic pathway is proposed. Phosmet is able to penetrate through the plant surface where the main metabolic reactions take place. Within the plant tissues only a limited transport is observed. The primary metabolic reactions are hydrolysis and conjugation reactions which produce phthalic acid and a range of related compounds, none of them containing the phosphorodithioate group. Oxidation reaction leading to the oxygen analogue phosmet oxon is a minor metabolic reaction. Considering the fact that oxygen analogue compounds are of high toxicity and the fact that no specific information on the toxicological significance of this compound is available, it was concluded to include phosmet oxon in the residue definition for risk assessment and monitoring purposes. However, pending on the outcome of the study aimed to address the relative potency of phosmet oxon in comparison with the parent compound, it might be necessary to reconsider the residue definitions. Supervised residue trials in oranges, apples and potatoes have been submitted, which allow the proposal of the following MRLs: oranges and pome fruit: 0.2 mg/kg, respectively, potatoes: 0.02* mg/ kg. No MRLs are proposed for other citrus fruit as the available trials in oranges are not suitable for extrapolation to the whole crop group. Supervised residue trials in oranges, apples and potatoes have been submitted, which allow the proposal of the following MRLs: oranges and pome fruit: 0.2 mg/kg, respectively, potatoes: 0.02* mg/kg. No MRLs are proposed for other citrus fruit as the available trials in oranges are not suitable for extrapolation to the whole crop group. The effects of processing on the nature and the level of residues were investigated. Under conditions simulating pasteurisation, baking/brewing/boiling and sterilisation, phosmet degraded to less toxic compounds or compounds that occurred also in animal metabolism studies. The transfer factors to apple juice, apple pure and canned apples were very low, with residues essentially left in the pomace and peel fractions. Studies on succeeding or rotational crops are not required due to the fast degradation of phosmet in soil. Livestock can be exposed to residues of phosmet through consumption of fruit pomace and potatoes. Metabolism studies in lactating goat and laying hens demonstrated that phosmet will not occur in animal tissues, milk and eggs when livestock is fed with feed produced according to GAP for the supported use. The consumer risk assessment was carried out taking into account chronic and acute exposures according to the provisional residue definition (sum of phosmet and phosmet oxon, expressed as phosmet). The calculations indicate that the exposure will be below the ADI and the ARfD, respectively. In aerobic laboratory soil degradation studies (20 degrees C, 21-50% soil maximum water holding capacity) phosmet exhibited low persistence and did not form any major (>10% AR) extractable non volatile soil metabolites. The major sink for the radiolabels used in the experiments was mineralisation to CO2 (5377% applied radioactivity (AR) at 120-150 days). Residue not extracted by acetone /acidified acetone accounted for 17-38% AR at 150 days. In field dissipation studies carried out in the USA phosmet also exhibited low persistence. Under laboratory (23 degrees C) anaerobic soil conditions the major (14.5% AR) metabolite N-hydroxymethyl phthalamic acid was identified. Based in the results of laboratory batch adsorption studies phosmet exhibited low mobility being considered immobile in one of the four soils tested. In a BBA guideline lysimeter study carried out in Switzerland that covers the applied for representative uses if applications are made in July, there was no leaching of radioactivity (excluding CO2) in collected leachate samples > 0.06 mu g/L, confirming the results of FOCUS scenario groundwater modelling for parent phosmet and indicating leaching of the soil metabolites that are formed at low levels is unlikely to be significant. All this information indicates, that for the applied for intended uses, the potential for groundwater exposure above the parametric drinking water limit of 0.1 mu g/L is negligible. In laboratory (20 degrees C) natural sediment water systems phosmet both dissipated rapidly by partitioning to sediment and degraded rapidly, resulting in it exhibiting very low persistence. The major (>10% AR) metabolites identified were: phthalamic acid phthalic acid and N-hydroxymethyl phthalimide. Based on the available sterile hydrolysis studies and laboratory aqueous photolysis study O, Odimethylphosphorodithioc acid and O, O-dimethylphosphoric acid may also be formed as major metabolites in natural surface waters. In sediment the only major component of the residue in addition to phosmet was phthalamic acid. All these identified breakdown products were themselves relatively labile. CO2 from the carbonyl radiolabel used in the natural sediment water studies was the major sink for the applied radioactivity (accounting for 80-92% AR at 100 days). FOCUS step 2 to 4 surface water assessments have been completed for parent phosmet (with step 4 just considering spray drift mitigation) but only southern European scenarios and then only early season application timings were simulated. As the applied for representative southern European uses assessed are not restricted to applications only being made later in the growing season, if phosmet is included in annex 1, then southern member states where later season uses are applied for, should carry out national assessments of the potential for surface water exposure and associated aquatic risk assessments from the drainage and runoff routes of entry to surface water, as it is not clear that the available EU level assessment covers these situations. Also the current assessment identifies that for the early season application southern European scenarios assessed, only 1 scenario for each crop (D6 potatoes, R4 citrus and pome fruit), represented a low risk to aquatic organisms without mitigation to reduce runoff input to surface water being considered. For all other geoclimatic situations assessed high risk was identified when only the spray drift risk was mitigated. A high acute risk to insectivorous birds was identified for all evaluated uses and also for herbivorous birds in potatoes. The initially identified high long-term risk to birds for all evaluated uses was reassessed based on measured residues in insects and grass. The refined long-term TER values for birds are above the Annex VI trigger. For a generic herbivorous mammal a potential high long-term risk was identified for all uses. The refined assessment based on selected focal mammalian species needs to be further justified. Phosmet is very toxic to aquatic organisms. Since data on acute toxicity to seven fish species are available the safety factor was lowered from 100 to 20. Risk mitigation measures to reduce spray drift input corresponding to 40 m in orchards and 20 m in potatoes are needed in order to meet this trigger for one FOCUS scenario in each crop. Based on data from an available mesocosm study, the same buffer zones will also be sufficient to protect aquatic invertebrates in southern Europe in case of early application for one FOCUS scenario in each crop. The risk assessment for the aquatic environment needs to be complemented with scenarios for later in the season, when drainage and runoff routes of entry are likely to contribute to the concentration in surface water from the assessed uses in southern Europe. Phosmet is very toxic to bees. The high risk needs to be managed at Member State level. Application should be avoided when there are likely to be any bees in the crop and a withholding period needs to be established. The risk to non-target arthropods is high. A potential for in-field recolonisation has been demonstrated, however further data is required to address the impact off-field and the potential for recolonisation from off-field areas. The risk to earthworms, other non-target soil macro-organisms, soil micro-organisms, non-target plants and biological methods of sewage treatment is considered to be low.
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共 5 条
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