Review of the existing maximum residue levels for chlormequat according to Article 12 of Regulation


European Food Safety Authority
EFSA Journal
EFSA Journal 2016;14(3):4422 [47 pp.].

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

Reasoned Opinion
On request from
European Commission
Question Number
24 February 2016
7 March 2016
European Food Safety Authority (EFSA), Parma, Italy
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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 chlormequat. In order to assess the occurrence of chlormequat residues in plants, processed commodities, rotational crops and livestock, EFSA considered the conclusions derived in the framework of Directive 91/414/EEC, the MRLs established by the Codex Alimentarius Commission 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 missing. Hence, the consumer risk assessment is considered indicative only and some MRL proposals derived by EFSA still require further consideration by risk managers. 


Chlormequat was included in Annex I to Directive 91/414/EEC on 1 December 2009 by Commission Directive 2009/37/EC, amended by Commission Directive 2010/2/EU, and has been deemed to be approved under Regulation (EC) No 1107/2009, in accordance with Commission Implementing Regulation (EU) No 540/2011, as amended by Commission Implementing Regulation (EU) No 541/2011. As the active substance was approved after the entry into force of Regulation (EC) No 396/2005 on 2 September 2008, EFSA is 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 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 PROFile and evaluation report provided by the RMS were made available to the Member States. A request for additional information was addressed to the Member States in the framework of a completeness check period which was initiated by EFSA on 24 June 2015 and finalised on 11 September 2015. After having considered all the information provided, EFSA prepared a completeness check report which was made available to Member States on 13 October 2015.

Based on the conclusions derived by EFSA in the framework of Directive 91/414/EEC, the MRLs established by the Codex Alimentarius Commission and the additional information provided by the RMS and Member States, EFSA prepared in December 2015 a draft reasoned opinion, which was circulated to Member States for consultation via a written procedure. Comments received by 3 February 2016 were considered during the finalisation of this reasoned opinion. The following conclusions are derived.

The metabolism of chlormequat chloride has been investigated in cereals as well as in rotational crops. A similar metabolism was depicted in these studies with chlormequat being the only relevant compound identified. Hydrolysis studies simulating beer brewing (100°C, pH 4 for 120 minutes) and bread making (100°C, pH 5 for 40 minutes) showed that processing conditions relevant for cereals are not expected to degrade the parent compound significantly but a general residue definition for processed commodities could not be derived in the absence of standard hydrolysis studies. Therefore, a residue definition for cereal crops for monitoring and risk assessment was proposed as the sum of chlormequat and its salts, expressed as chlormequat chloride. The residue definition derived for cereals was also deemed appropriate for pears and cultivated fungi where carry-over of unchanged parent compounds may occurs. A validated analytical method for this residue definition in high water content, dry commodities and cereal straw is available.

The available residue trials data were considered sufficient to derive MRL proposals as well as risk assessment values for all primary crops under evaluation, except for grass which residue trials were not available. Based on the metabolism studies, no significant residues levels of chlormequat are expected in the investigated rotational crops (cereals, roots, pulses and oilseeds and leafy crops), the main part of the radioactivity being incorporated in the plant matrix. However, EFSA derived MRLs proposals in order to cover unintentional carry-over of residues in pears (due to former uses) and cultivated fungi (grown on substrate composed of cereals straw treated with chlormequat). Different options for MRLs were derived on the basis on monitoring data and different methodologies. A risk management decision should still be taken on the level of these MRLs and the period of their applicability. In addition, studies investigating the magnitude of residues in processed commodities of wheat, barley and oats allowed EFSA to derive robust processing factors for wheat (bran, flour and bread), barley (pot/pearl, malt and beer) and oat flakes.

Chlormequat is authorised for use in cereals which might be fed to livestock. The metabolism of chlormequat was investigated in lactating goats and laying hens. As metabolic pathways are expected to be similar in ruminants and pigs, the results of the goat metabolism study could be extrapolated to swine. From these studies, EFSA proposed a general residue definition for monitoring and risk assessment in livestock commodities as the sum of chlormequat and its salts, expressed as chlormequat chloride. A validated analytical method for enforcement of the proposed residue definition in commodities of animal origin is available. Based on the available feeding studies for ruminants and poultry, MRLs and risk assessment values were derived in ruminants, swine and poultry products.

Chronic and acute consumer exposure resulting from the authorised uses reported in the framework of this review and the possible carry-over in non-treated pears and cultivated fungi (considering the most protective assumption) was calculated using revision 2 of the EFSA PRIMo. The highest chronic exposure represented 28.9% of the ADI (Danish children) and the highest acute exposure amounted to 33.1% of the ARfD (wheat).

Apart from the MRLs evaluated in the framework of this review, internationally recommended CXLs have also been established for chlormequat. Additional calculations of the consumer exposure, considering these CXLs, were therefore carried out and the highest chronic exposure represented 29.3% of the ADI (Danish children) and the highest acute exposure amounted to 62.3% of the ARfD (milk and milk products).

chlormequat, MRL review, Regulation (EC) No 396/2005, consumer risk assessment, quaternary ammonium, plant growth regulator
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