Review of the existing maximum residue levels for triadimenol according to Article 12 of Regulation (EC) No 396/2005


European Food Safety Authority
EFSA Journal
EFSA Journal 2016;14(1):4377 [51 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
18 December 2015
18 January 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 triadimenol. In order to assess the occurrence of triadimenol 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. 


Triadimenol was included in Annex I to Directive 91/414/EEC on 1 September 2009 by Commission Directive 2008/125/EC, 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 27 April 2015 and finalised on 29 June 2015. After having considered all the information provided, EFSA prepared a completeness check report which was made available to Member States on 31 August 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 November 2015 a draft reasoned opinion, which was circulated to Member States for consultation via a written procedure. Comments received by 14 December 2015 were considered during the finalisation of this reasoned opinion. The following conclusions are derived.

The metabolism of triadimenol was investigated for foliar application in fruits and fruiting vegetables (grapes), for foliar and seed application in cereals (wheat and barley) and for foliar application on root and tuber vegetables (sugar beet). Rotational crop metabolism was also investigated in three different crop groups (root crops, leafy crops and cereals). According to all the available studies a general residue definition for enforcement in all plant commodities is proposed as triadimenol (sum of all constituent isomers). For risk assessment, it is proposed to include in the residue definition the parent triadimenol, the hydroxy metabolite M10 and their conjugates expressed as triadimenol. Based on the results from rotational crops and hydrolysis studies, the proposed residue definitions also apply to rotational crops and processed commodities and no significant residues are expected in rotational crops. A validated analytical method for enforcement of the proposed residue definition is available for high water content, acidic, high oil content, dry commodities and hops. Available metabolism studies also allowed deriving the following conversion factors for risk assessment: 1 for root and tuber vegetables; 2 for cereal straw and grain; 1.4 for fruits and fruiting vegetables.

The available data are considered sufficient to derive MRL proposals as well as risk assessment values for all commodities under evaluation, except for strawberries, Brussels sprouts, leek and sugar beet where the available data were insufficient to derive MRLs proposal and risk assessment values. Considering the data gaps identified for residues and for storage stability studies, all the derived MRL proposals are only tentative.

Triadimenol is authorised for use on crops that might be fed to livestock and the livestock dietary burden calculated for all groups of livestock was found to exceed the trigger value of 0.1 mg/kg DM. Metabolism of triadimenol was investigated in lactating goat and laying hens. As metabolic pathways were generally found to be similar between rodents and ruminants, the results of the goat metabolism study can be extrapolated to pigs. The residue for monitoring in commodities of animal origin is defined as the sum of triadimenol (any ratio of constituent isomers) its hydroxy metabolite (M10), their conjugates and M28, expressed as triadimenol. For risk assessment the residue definition is proposed as the sum of triadimenol (any ratio of constituent isomers), its hydroxy metabolite (M10), its carboxy metabolite (M02), their conjugates and M28, expressed as triadimenol. Based on the metabolism study, it is concluded that residue levels of triadimenol and its metabolites remain below 0.01 mg/kg in all tissues, in milk and in eggs. A validated analytical method for enforcement of the proposed residue definition is not available. Therefore, MRLs and risk assessment values for all animal commodities are tentatively established at the default LOQ of 0.01 mg/kg.

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 multiplied for the conversion factors (CF) derived from the metabolism studies for an indicative calculation. Since metabolism studies covering the leafy vegetables and the oilseeds groups were not available, it was not possible to derive CFs for rapeseed, globe artichokes, Brussels sprouts and hops. Consequently, for these commodities, the worst case CF of 2 has been applied for risk assessment. The highest chronic exposure was calculated for British toddler, representing 7.5% of the ADI, and the highest acute exposure was calculated for table grapes, representing 37% of the ARfD. Although (major) uncertainties remain due to the data gaps identified in the previous sections, this indicative exposure calculation did not indicate a risk to consumers.

triadimenol, MRL review, Regulation (EC) No 396/2005, consumer risk assessment, conazole, fungicide, triazole derivative metabolites
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