UE: autoridad alimentaria revisa límites máximos de residuo para thifensulfuron-methyl

Abstract 

According to Article 12 of Regulation (EC) No 396/2005, the European Food Safety Authority (EFSA) has reviewed the Maximum Residue Levels (MRLs) currently established at European level for the pesticide active substance thifensulfuron-methyl. In order to assess the occurrence of thifensulfuron-methyl residues in plants, processed commodities, rotational crops and livestock, EFSA considered the conclusions derived in the framework of Directive 91/414/EEC, as well as the European authorisations reported by Member States (incl. the supporting residues data). Based on the assessment of the available data, MRL proposals were derived and a consumer risk assessment was carried out. Although no apparent risk to consumers was identified, some information required by the regulatory framework was found to be missing. Hence, the consumer risk assessment is considered indicative only and one MRL proposal derived by EFSA still requires further consideration by risk managers. 

© European Food Safety Authority, 2012 

Summary 

Thifensulfuron-methyl was included in Annex I to Directive 91/414/EEC on 01 July 2002, which is before the entry into force of Regulation (EC) No 396/2005 on 02 September 2008. EFSA is therefore required to provide a reasoned opinion on the review of the existing MRLs for that active substance in compliance with Article 12(2) of the afore mentioned regulation. In order to collect the relevant pesticide residues data, EFSA asked France, as the designated rapporteur Member State (RMS), to complete the Pesticide Residues Overview File (PROFile). The requested information was submitted to EFSA on 10 December 2008 and, after having considered several comments made by EFSA, the RMS provided on 27 October 2009 a revised PROFile. 

Based on the conclusions derived in the framework of Directive 91/414/EEC and the additional information provided by the RMS, EFSA issued on 01 March 2012 a draft reasoned opinion that was circulated to Member States’ experts for consultation. Comments received by 04 May 2012 were considered for finalisation of this reasoned opinion. The following conclusions are derived. 

The toxicological profile of thifensulfuron-methyl was evaluated in the framework of Directive 91/414/EEC, which resulted in an ADI being established at 0.02 mg/kg bw per d. An ARfD was not deemed necessary. 

The metabolism of thifensulfuron-methyl was investigated in field grown wheat following foliar spray application of radiolabelled active substance at the application rate of 74-80 g as/ha at the 5 leaves stage. The elimination of thifensulfuron-methyl was rapid (approximately 2 days). Total residues in mature forage and straw were in the range of 0.45-0.80 mg/kg for the radiolabelled test material. No significant residues (<0.01 mg/kg) of the parent compound or its metabolites in mature wheat grain were detected two months after treatment. An additional metabolism study on soya bean was reported by the RMS during the Member State consultation. No significant residues (≤ 0.01 mg/kg) of the parent compound or its metabolites in soybean seed or pods were detected at harvest (100 days after treatment). Therefore the residue definition for risk assessment and enforcement was thifensulfuron-methyl. This residue definition is limited to the evaluated foliar use on cereals and pulses & oilseeds. Validated analytical methods for enforcement of parent thifensulfuron-methyl are available with an LOQ of 0.01 mg/kg in dry, acidic, high water and high fat containing commodities. 

Regarding the magnitude of residues in primary crops, a sufficient number of supervised residue trials are available for most of the GAPs reported by the RMS, which allowed EFSA to estimate the expected residue concentrations in the relevant plant commodities and to derive appropriate MRLs. For linseed, data were not sufficient to derive an MRL and further residues trials are still required. It is noted that for grass, MRLs were derived resulting from the use of thifensulfuron-methyl on this crop in one climatic zone but a data gap was identified regarding application in the other climatic zone. 

As quantifiable residues of thifensulfuron-methyl are not expected in the treated crops, there is no need to investigate the effect of industrial or household processing. In addition, the chronic exposure does not exceed 10 % of the ADI. 

Residues in rotational crops were studied in peas, beet root, sunflower and wheat. The primary plant metabolism study corresponds with the residues observed in rotational crops where the majority of the radioactivity could be attributed to incorporation into natural compounds or minor unidentified fractions. Residues exceeding the LOQ are therefore not expected in rotational crops. 

The metabolism of thifensulfuron-methyl was investigated in lactating goats dosed with 0.71 mg/kg bw per d of thifensulfuron-methyl corresponding to approximately 25 times the maximum exposure of meat ruminants. The study demonstrated that the transfer of residues in milk and tissues, at this rate is relatively low. Thifensulfuron-methyl was the major component found in milk, muscle and tissues. Hence it was concluded that the residue definition for risk assessment and enforcement in ruminants and swine products should be thifensulfuron-methyl. Detectable residues in ruminants and swine commodities are also not expected and validated analytical methods for enforcement of the residue definition are available with an LOQ of 0.01 mg/kg in milk, cream, meat, fat, liver, kidney and eggs. MRLs and risk assessment values for the relevant commodities in ruminants and pigs are therefore established at 0.01 mg/kg. MRLs for poultry products are not required because poultry is not expected to be exposed to significant levels of thifensulfuron-methyl residues. 

Chronic consumer exposure resulting from the uses supported in the framework of this review was calculated using revision 2 of the EFSA PRIMo. For those commodities where data were insufficient to derive an MRL, EFSA considered the existing EU MRL for an indicative calculation. Considering these crops, the highest chronic exposure represented 3.8 % of the ADI (Dutch child). Acute exposure calculations were not carried out because an ARfD was not deemed necessary for this active substance. 

Based on the above assessment, EFSA does not recommend inclusion of this active substance in Annex IV to Regulation (EC) No 396/2005. MRL recommendations were derived in compliance with the decision tree reported in Appendix D of the reasoned opinion (see summary table). All MRL values listed as ‘Recommended’ in the table are sufficiently supported by data and are therefore proposed for inclusion in Annex II to the Regulation. The remaining MRL values listed in the table are not recommended for inclusion in Annex II because they require further consideration by risk managers (see summary table footnotes for details). In particular, one existing EU MRL needs to be confirmed by the following data: 

• 4 residues trials supporting the northern outdoor GAP on linseed; 

It is highlighted that the assessment for grass results from a GAP in one climatic zone only. EFSA therefore identified the following data gap which is not expected to impact on the validity of the MRLs derived but which might have an impact on national authorisation: 

• 4 additional residues trials supporting the southern outdoor GAP on grass. 

If the above reported data gaps are not addressed in the future, Member States are recommended to withdraw or modify the relevant authorisations at national level. 

Minor deficiencies were also identified in the assessment but these deficiencies are not expected to impact either on the validity of the MRLs derived or on the national authorisations. The following data are therefore considered desirable but not essential: 

• a detailed evaluation report on the storage stability and storage conditions of residue trials samples; 

• a detailed evaluation report of the ruminant metabolism study reported in the DAR.

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