Reasoned opinion on the review of the existing maximum residue levels (MRLs) for metazachlor according to Article 12 of Regulation (EC) No 396/2005

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Article
European Food Safety Authority
EFSA Journal
EFSA Journal 2014;12(4):3634 [51 pp.].
doi
10.2903/j.efsa.2014.3634
Acknowledgements

EFSA wishes to thank the rapporteur Member State the United Kingdom for the preparatory work on this scientific output.

Type
Reasoned Opinion
On request from
EFSA
Question Number
EFSA-Q-2009-00144
Approved
1 April 2014
Published
7 April 2014
Last Updated
20 June 2014. This version replaces the previous one/s.
Affiliation
European Food Safety Authority (EFSA), Parma, Italy
Note
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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 metazachlor. In order to assess the occurrence of metazachlor 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 some MRL proposals derived by EFSA still require further consideration by risk managers.

Summary

Metazachlor was included in Annex I to Directive 91/414/EEC on 01 August 2009, which is after 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(1) of the aforementioned regulation. In order to collect the relevant pesticide residues data, EFSA asked the the United Kingdom, as the designated rapporteur Member State (RMS), to complete the Pesticide Residues Overview File (PROFile) and to prepare a supporting evaluation report. The requested information was submitted to EFSA on 18 January 2011 and, after having considered several comments made by EFSA, the RMS provided on 18 December 2012 a revised PROFile.

Based on the conclusions derived by EFSA in the framework of Directive 91/414/EEC and the additional information provided by the RMS, EFSA issued on 14 October 2013 a draft reasoned opinion that was circulated to Member States’ experts for consultation. Comments received by 13 December 2013 were considered in the finalisation of this reasoned opinion. The following conclusions are derived.

The toxicological profile of metazachlor was evaluated in the framework of Directive 91/414/EEC, which resulted in an ADI and an ARfD being established at 0.08 mg/kg bw per d and 0.5 mg/kg bw, respectively.

Primary crop metabolism of metazachlor was investigated in cereals, pulses and oilseeds and leafy vegetables following soil or foliar application. Based on these studies, EFSA proposes to define the residue for risk assessment in plants as the sum of metazachlor and its metabolites containing the 2,6‑dimethylaniline moiety, expressed as metazachlor. For enforcement purposes the major metabolites 479M04, 479M08 and 479M16 are deemed to be sufficient markers. Validated analytical methods for enforcement of this residue definition are available.

Regarding the magnitude of residues, the available data were sufficient to derive tentative MRLs for all commodities under evaluation, except for oranges, lemons, tree nuts, pome fruits, stone fruits, berries and small fruits, potatoes, rocket and asparagus where residues data were insufficient to derive MRLs and risk assessment values and for garlic, Brussels sprouts, globe artichokes, leek and oilseeds, where data were sufficient to derive appropriate MRLs and risk assessment values.

The effect of industrial and/or household processing on the nature of metazachlor residues was investigated. Pasteurisation, baking/brewing/boiling and sterilisation are not expected to have a significant impact on the composition of residues in matrices of plant origin. Further processing studies are not required as they are not expected to affect the outcome of the risk assessment. However, if more robust processing factors were to be required by risk managers, in particular for enforcement purposes, additional processing studies would be needed.

The potential incorporation of soil residues into succeeding and rotational crops was investigated in leafy vegetables, root and tuber vegetables and cereals during the peer review and the residue definition set for the primary crops also applies to the rotational crops. Magnitude of residues in succeeding and rotational crops was also investigated. Significant residues were recovered in straw from cereal grown in rotation; however these residues are not expected to impact MRLs for plant and animal products, provided that metazachlor is applied in compliance with the GAPs supported in the framework of this review.

Based on the uses reported by the RMS, significant intakes were calculated for poultry, ruminants and pigs. Metabolism of metazachlor in lactating ruminants was shown to be extensive. The general metabolic pathways in rodents and ruminants were found to be comparable and the findings in ruminants can therefore be extrapolated to pigs. Metabolism in poultry was also investigated and it was demonstrated that no significant residues (i.e. above 0.01 mg/kg) are expected in eggs or tissues at the maximum dietary burden. Therefore, EFSA concludes that the residue definition proposed for monitoring and risk assessment in animal commodities should be the sum of metazachlor and its metabolites containing the 2,6‑dimethylaniline moiety, expressed as metazachlor. Validated analytical methods for enforcement of the proposed residue definition in food of animal origin are available. MRLs are proposed for liver of ruminants and pigs based on the reported cow feeding study performed with metazachlor. MRLs in other ruminant and pig matrices, in milk and in poultry commodities can be established at the LOQ.

Chronic and acute consumer exposure resulting from the authorised uses reported 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. The highest chronic exposure was calculated for Dutch children, representing 4.5 % of the ADI, and the highest acute exposure was calculated for potatoes, representing 9.2 % of the ARfD.

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, some tentative MRLs or existing EU MRLs need to be confirmed by the following data:

  • 8 residue trials on oranges or lemons, supporting the southern outdoor GAP for citrus fruit;
  • 4 residue trials on apples, 4 trials on a stone fruit supporting the northern outdoor GAP for tree nuts, pome fruits and stone fruits;
  • 4 residue trials on strawberries and 4 residue trials on either grapes, currant or another type of berries, supporting the northern outdoor GAP for berries & small fruits;
  • 8 residue trials supporting the northern outdoor GAP for potatoes;
  • 8 residue trials supporting the southern outdoor GAP for potatoes;
  • 4 residue trials supporting the northern outdoor GAP for radish;
  • 4 residue trials supporting the indoor GAP for radish;
  • 4 residue trials on turnips supporting the northern outdoor GAP for turnips, swedes and horseradish;
  • 8 residue trials (4 on cauliflower and 4 on broccoli) supporting the northern outdoor GAP for flowering brassica;
  • 8 residue trials (4 on cauliflower and 4 on broccoli) supporting the southern outdoor GAP on flowering brassica;
  • 8 residue trials supporting the northern outdoor GAP for head cabbage;
  • 4 residue trials supporting the southern outdoor  GAP for  head cabbage;
  • 4 residue trials on kale supporting the northern outdoor GAP for leafy brassica;
  • 4 residue trials on kale supporting the southern outdoor GAP on leafy brassica;
  • 4 residue trials supporting the northern outdoor GAP for kohlrabi;
  • 4 residue trials supporting the northern outdoor GAP for rocket;
  • 4 residue trials supporting the northern outdoor GAP for asparagus.
  • 4 residue trials supporting the northern outdoor GAP for rape forage.

All required residue trials should include results compliant with the proposed residue definition for enforcement. It is highlighted that, when submitting residue trials compliant with the residue definition for enforcement, a storage stability study on metabolites 479M08 and 479M04 in high oil content, dry and acidic commodities would also be required.

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 actions and data are therefore considered desirable but not essential:

  • clarification on the origin of the metabolite 2-hydroxymethyl-6-methylaniline observed in liver and kidney during the metabolism study and confirmation on samples extraction in the livestock feeding studies.
Keywords
metazachlor, MRL review, Regulation (EC) No 396/2005, consumer risk assessment, chloroacetanilide, herbicide
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