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Reasoned opinion on the review of the existing maximum residue levels (MRLs) for imazosulfuron according to Article 12 of Regulation (EC) No 396/2005
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 imazosulfuron. In order to assess the occurrence of imazosulfuron 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 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 all MRL proposals derived by EFSA still require further consideration by risk managers.
© European Food Safety Authority, 2012
Imazosulfuron was included in Annex I to Directive 91/414/EEC on 01 April 2005, 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 afore mentioned regulation. In order to collect the relevant pesticide residues data, EFSA asked Germany, as the designated rapporteur Member State (RMS), to complete the Pesticide Residues Overview File (PROFile). The requested information was submitted to EFSA on 12 August 2009 and, after having considered several comments made by EFSA, the RMS provided on 31 May 2010 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 August 2012 a draft reasoned opinion that was circulated to Member State experts for consultation. Comments received by 05 October 2012 were considered in the finalisation of this reasoned opinion. The following conclusions are derived.
The toxicological profile of imazosulfuron was evaluated in the framework of Directive 91/414/EEC, which resulted in an ADI being established at 0.75 mg/kg bw per d. An ARfD was not deemed necessary.
Primary crop metabolism of imazosulfuron was investigated following soil application in rice and foliar application in wheat. Based on these studies, the relevant residue for enforcement and risk assessment in cereals could be defined as imazosulfuron. A validated analytical method for enforcement of this residue definition is also available, with an LOQ of 0.01 mg/kg in dry commodities.
Regarding the magnitude of residues in all crops reported by the RMS, a sufficient number of supervised residues trials is available for barley, rice, rye and wheat. However storage stability needs to be confirmed in dry commodities and straw. Therefore EFSA was only able to estimate the expected residue concentrations in the relevant plant commodities and to propose MRL values on a tentative basis.
Quantifiable residues of imazosulfuron are not expected in cereal grains and the chronic exposure does not exceed 10 % of the ADI. There was therefore no need to investigate the effect of industrial and/or household processing on the nature and magnitude of residue and specific processing factors for enforcement of processed commodities are not proposed.
Occurrence of imazosulfuron residues in rotational crops was already investigated during the peer review of imazosulfuron. Based on the available data, it can be concluded that significant residues are not expected in cereal crop grown in rotation with the primary cereals. However, according to the current guidance, further investigation should be conducted in two additional rotational crop groups. If this is not further investigated, Member States should consider defining restrictions regarding the rotation of crops when authorising the active substance.
Based on the uses reported by the RMS, no significant exposures of animals to imazosulfuron are expected and no MRLs are thus required on food of animal origin.
Chronic consumer exposure resulting from the authorised uses reported in the framework of this review was calculated and compared with the toxicological reference value derived for imazosulfuron. The highest chronic exposure was calculated for Danish children, representing 0.01 % of the ADI. 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 this reasoned opinion (see also summary table). None of the MRL values listed in the table are recommended for inclusion in Annex II to the Regulation as they are not sufficiently supported by data (see summary table footnotes for details). All tentative MRLs need to be confirmed by the following data:
- a study investigating storage stability of imazosulfuron in dry commodities over a period of at least two years (study is planned for completion in December 2012).
In addition, EFSA 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 authorisations:
- a study investigating the nature and magnitude of residues in rotational crops in at least two additional crop groups.
If the above reported data gap is not addressed in the future, Member States are recommended to define restrictions regarding the rotation of crops when authorising the active substance.
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:
- detailed information about the unknown residue fraction in leaf blades in rice.
Imazosulfuron, MRL review, Regulation (EC) No 396/2005, consumer risk assessment, pyrimidinylsulfonylurea, herbicide.