Reasoned opinion on the modification of the existing MRL for guazatine in citrus fruits

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Article
European Food Safety Authority
EFSA Journal
EFSA Journal 2014;12(8):3818 [29 pp.].
doi
10.2903/j.efsa.2014.3818
Type
Reasoned Opinion
On request from
European Commission
Question Number
EFSA-Q-2013-00741
Approved
25 August 2014
Published
28 August 2014
Affiliation
European Food Safety Authority (EFSA), Parma, Italy
Note
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Abstract

In accordance with Article 6 of Regulation (EC) No 396/2005, the United Kingdom, hereafter referred to as the evaluating Member State (EMS), received an application from Exponent International Ltd., on behalf of ICA International Chemicals (PTY) Ltd., to set an import tolerance for the active substance guazatine in citrus fruits. In order to accommodate for the reported post-harvest use of guazatine acetates in South Africa, the United Kingdom proposed the MRL of 4 mg/kg. The United Kingdom drafted an evaluation report in accordance with Article 8 of Regulation (EC) No 396/2005, which was submitted to the European Commission and forwarded to EFSA. According to EFSA the metabolism of guazatine acetates in citrus fruits is not fully elucidated. A tentative MRL proposal of 5 mg/kg for guazatine acetates (corresponding to 4 mg/kg for residues expressed as guazatine) was derived. This MRL proposal should be considered as tentative. The MRL set in the country of origin is 5 mg/kg for guazatine. Although the indicative consumer risk assessment did not identify a consumer health risk for the reported post-harvest use of guazatine acetates on citrus fruits imported from South Africa, EFSA does not propose to set a MRL in citrus since the risk assessment is affected by a high level of scientific uncertainties resulting from the validity of the toxicological reference values, the lack of elucidation of the metabolic pathway in plants and livestock and the validity of the supervised residue trials analysed with an analytical method which is based on the analysis of one constituent of the technical material (marker substance GG-diacetate) only. Thus, EFSA is of the opinion that the available data are not sufficient to demonstrate that the residues of guazatine acetates on citrus fruits resulting from the South African GAP are safe for European consumers.

Summary

In accordance with Article 6 of Regulation (EC) No 396/2005, the United Kingdom, hereafter referred to as the evaluating Member State (EMS), received an application from Exponent International Ltd., on behalf of ICA International Chemicals (PTY) Ltd., to set an import tolerance for the active substance guazatine in citrus fruits. In order to accommodate for the reported post-harvest use of guazatine acetates in South Africa, the United Kingdom proposed the MRL of 4 mg/kg. The United Kingdom drafted an evaluation report in accordance with Article 8 of Regulation (EC) No 396/2005, which was submitted to the European Commission and forwarded EFSA on 30 August 2013.

Guazatine is a mixture of products resulting from the amidination of technical iminodi(octamethylene)diamine, containing numerous guanidines and polyamines. It is no longer authorised for use in plant protection products within the EU. EFSA reviewed the existing MRLs in the framework of the MRL review under Article 12 of Regulation (EC) No 396/2005 and proposed to lower all MRLs to the appropriate LOQ as no import tolerances were notified.
This assessment is based on the evaluation report and the additional information and clarifications submitted by the EMS upon requests of EFSA, the Draft Assessment Report (DAR) and its addendum prepared under Council Directive 91/414/EEC, the EFSA conclusion on the peer review of the pesticide risk assessment of the active substance guazatine as well as the reasoned opinion on the review of all existing MRLs and the JMPR evaluation report.

The toxicological profile of guazatine was assessed in the framework of the peer review under Council Directive 91/414/EEC. Based on the available information an ADI of 0.0048 mg/kg bw per day and an ARfD of 0.04 mg/kg bw were proposed for guazatine acetates, which is the variant used in plant protection products. Since a clear conclusion on whether the active substance used in the toxicological studies is representative for the active substance guazatine acetates contained in the South African plant protection product for which the import tolerance is requested can not be drawn, the toxicological reference values should be considered as indicative.
Metabolism studies in orange fruits under post-harvest storage conditions were provided in the framework of the import tolerance request. The studies were conducted using individually the GG-diacetate or the GGG-triacetate, two of the constituents of technical guazatine. EFSA is of the opinion that the studies are not sufficient to fully elucidate the metabolism of guazatine acetates in citrus fruits. EFSA does not agree with the position of the applicant that GG-diacetate and GGG-triacetate are fully representative for the metabolism of guazatine acetates in citrus fruits and that the results for these two components can be extrapolated to the other components of the mixture. The assumption that the metabolic behaviour of all constituents contained in guazatine is comparable with the metabolism of GG-diacetate and GGG-triacetate needs to be confirmed with appropriate studies. Consequently, a final decision on the residue definition cannot be taken and further information is required. Tentatively and in order to perform an indicative risk assessment, EFSA used the residue definition for enforcement and risk assessment as guazatine acetates.

Based on the results of eight residue trials reflecting the GAP, a tentative MRL proposal of 5 mg/kg for guazatine acetates (corresponding to 4 mg/kg for residues expressed as guazatine) was derived. The MRL set in the country of origin is 5 mg/kg for guazatine. This MRL proposal should be considered as tentative given the uncertainty with regard to the residue definition and the validity of the supervised residue trials analysed with an analytical method which needs to be demonstrated to be fit for the purpose.

Studies conducted using either the GG-diacetate or the GGG-triacetate components of guazatine acetates showed that these compounds were hydrolytically stable under pasteurisation conditions. The behaviour of the other guazatine constituents was not investigated. To conclude on the residue definition for processed citrus products a hydrolysis study conducted with other components representative for guazatine acetates is required, including other test conditions like sterilisation. An indicative peeling factor was derived from residue trials where the distribution between pulp and peel was measured. Processing studies on the magnitude of residues conducted according to the current standard would be required as the residue levels in raw agricultural commodities (RAC) exceed the trigger value of 0.1 mg/kg.

Since the use of guazatine is on imported permanent crops treated post-harvest, investigations of residues in rotational crops are not required.

Considering that citrus pomace obtained from the processing of the imported fruits may be fed to animals, the potential carry-over into food of animal origin was assessed. The indicative calculated livestock dietary burdens significantly exceed the trigger value of 0.1 mg/kg (dry matter) for ruminants. The nature of guazatine residues was investigated in lactating cows. Since a full characterisation of the residues was not carried out, this study is not adequate to elucidate the metabolism of guazatine in livestock and to conclude on a residue definition for animal products. Further information is necessary to conclude on the need to set MRLs in bovine, sheep and goat edible tissues and milk resulting from the post-harvest treatment on citrus fruits.

The consumer risk assessment was performed with revision 2 of the EFSA Pesticide Residues Intake Model (PRIMo). EFSA updated the long-term risk assessment performed in the framework of the review of the existing MRLs for guazatine acetates according to Article 12 of Regulation (EC) No 396/2005 with the tentative median residue value for citrus fruits derived from the submitted supervised residue trials. The acute exposure assessment was performed only with regard to citrus fruits using the MRL established in the country of origin, as worst case. The input values were corrected by the peeling factor to take into account the lower residues expected in the peeled citrus.

Based on the above calculation, no long-term consumer intake concerns were identified for any of the European diets incorporated in the EFSA PRIMo. The total calculated intake accounted for up to 74 % of the ADI (Dutch child diet). The contribution of residues in citrus fruits to the total consumer exposure accounted for a maximum of 7.9 % of the ADI for oranges, 1.5 % of the ADI for mandarins and less for grapefruits, lemons, limes and the other citrus fruits. No acute consumer risk was identified in relation to the MRL set for citrus fruits in the country of origin. The calculated maximum exposure in percentage of the ARfD was 99.5 % for oranges, 67 % for grapefruits, 42 % for mandarins, 26 % for lemons and 15 % for limes.

Although the indicative consumer risk assessment did not identify a consumer health risk for the reported post-harvest use of guazatine acetates on citrus fruits imported from South Africa, EFSA does not propose to set a MRL in citrus since the risk assessment is affected by a high level of scientific uncertainties resulting from the validity of the toxicological reference values, the lack of elucidation of the metabolic pathway in plants and livestock and the validity of the supervised residue trials analysed with an analytical method which is based on the analysis of one constituent of the technical material (marker substance GG-diacetate) only. Thus, EFSA is of the opinion that the available data are not sufficient to demonstrate that the residues of guazatine acetates on citrus fruits resulting from the South African GAP are safe for European consumers.

Keywords
guazatine, citrus fruits, MRL application, Regulation (EC) No 396/2005, consumer risk assessment, guanidine fungicide, GG-diacetate
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Number of Pages
29