Consequently, the MRL proposal would refer to borage and echium (Echium plantagineum). In order to accommodate for the intended use of diquat, the EMS proposed to raise the existing MRL for borage from the limit of quantification (LOQ) of 0.1 mg/kg to 2 mg/kg. The EMS drafted an evaluation report according to Article 8 of Regulation (EC) No 396/2005, which was submitted to the European Commission and forwarded to EFSA.
EFSA concluded that the quality of the available residue trials does not meet the current quality standards. The residue trials showed deficiencies with regard to the validation of the analytical method used to analyse the samples. Furthermore, the samples were not stored under conditions for which the sample integrity was demonstrated. Considering these uncertainties regarding the residue concentrations measured in the residue trials, EFSA did not derive a MRL proposal for borage and echium to support the intended use. Residue trials compliant with the currently applicable EU guidelines have to be submitted to support the intended use on echium (Echium plantagineum) in the NEU.
Given the long-term exposure concerns identified for the existing EU MRLs for diquat, new uses currently cannot be authorized before a comprehensive review of the existing MRLs has been performed. EFSA also notes that for a future MRL application it would be necessary to provide background information on the existing EU MRLs (GAPs, residue trials, processing studies) which would be required to make a more accurate estimation of the long-term exposure resulting from the existing uses and to derive a sound conclusion on the safety of new MRLs for diquat.
Summary
In accordance with Article 6 of Regulation (EC) No 396/2005, the United Kingdom, herewith referred to as the evaluating Member State (EMS), received an application from the company Technology Crops Ltd. to modify the existing MRL for diquat in borage. The actual proposal is made to accommodate the intended use of diquat on echium (Echium plantagineum), but this crop is not listed in Annex I of Regulation (EC) No 396/2005. Since echium (Echium plantagineum) is of the same family (Boraginaceae) as borage, the EMS proposed to consider it under the same food classification code as borage. Consequently, the MRL proposal would refer to borage and echium (Echium plantagineum). In order to accommodate for the intended use of diquat, the EMS proposed to raise the existing MRL for borage from the limit of quantification (LOQ) of 0.1 mg/kg to 2 mg/kg. The EMS drafted an evaluation report according to Article 8 of Regulation (EC) No 396/2005, which was submitted to the European Commission and forwarded to EFSA on 13 September 2011.
EFSA bases its assessment on the evaluation report submitted by the EMS (UK, 2011), the Draft Assessment Report (DAR) (and its addendum) prepared under Council Directive 91/414/EEC (UK, 1996, 1999), the Commission Review Report on diquat (EC, 2001) and the JMPR Evaluation report (FAO, 1994).
The toxicological profile of diquat was assessed in the framework of the peer review under Directive 91/414/EEC and the data were sufficient to derive an ADI value of 0.002 mg/kg bw per day. No ARfD was deemed necessary.
The metabolism of diquat in primary crops was investigated in fruit and fruiting vegetables, root and tuber vegetables, pulses and oilseeds, and cereals. The available metabolism studies indicate that diquat undergoes rapid and extensive photochemical degradation in plants and the rate of degradation depends on the light intensity. The main photodegradation product identified was 1,2,3,4-tetrahydro-1-oxo-pyrido (1,2a)-5-pyrazinium chloride (TOPPS). Based on the available studies the peer review concluded that diquat (cation) is to be defined as the relevant residue for the risk assessment and enforcement. The current residue definition according to Regulation (EC) No 396/2005 is established as diquat (cation). The metabolism study on rape seed indicates that parent diquat cation is the relevant residue in oilseeds. Thus, noting the deficiencies of the available metabolism studies which are not fully in accordance with currently applicable EU guidelines, the conclusion regarding residue definitions can be extrapolated to echium and borage. It would be desirable to get the findings regarding the plant metabolism of diquat confirmed by providing metabolism studies performed according to the current standards. An adequate analytical enforcement method is available to control the residues of diquat in high oil content matrices.
The applicant referred to the residue trials on rape seed as performed for the peer review and proposed to extrapolate residue data to borage and consequently to echium. Although the peer review based on these trials derived a MRL of 1 mg/kg for diquat in rape seed, EFSA concluded that the quality of the available residue trials does not meet the current quality standards. The residue trials showed deficiencies with regard to the validation of the analytical method used to analyse the samples. Furthermore, the samples were not stored under conditions for which the sample integrity was demonstrated. Considering these uncertainties regarding the residue concentrations measured in the residue trials, EFSA did not derive a MRL proposal for borage and echium to support the intended use. Residue trials compliant with the currently applicable EU guidelines have to be submitted to support the intended use on echium (Echium plantagineum) in the NEU.
The effect of processing on the nature of diquat residues in processed plant products has not been investigated and therefore such studies should be performed.
The nature and magnitude of diquat residues in rotational/succeeding crops and in livestock was not investigated since the intended use on the crops under consideration is not supported.
EFSA performed an indicative consumer risk assessment for the existing EU MRLs for diquat as established in Regulation (EC) No 396/2005. The consumer risk assessment was performed with revision 2 of the EFSA Pesticide Residues Intake Model (PRIMo). Using the existing EU MRLs as input values, chronic consumer exposure concerns could not be excluded for 17 European diets. The total calculated intake values accounted for up to 889% of the ADI (maximum for IE adult diet). The main contributors were barley and maize. When using the available median residue values for rape seed, oats and barley, the chronic consumer exposure accounted for up to 327% of the ADI (maximum for IE adult diet). EFSA is aware that further refinements of the exposure estimation could be done, provided that detailed information regarding the authorized GAPs, residue trials and processing studies are made available.
EFSA concludes that the intended use of diquat on echium (Echium plantagineum) is not sufficiently supported by residue data.
Given the long-term exposure concerns identified for the existing EU MRLs for diquat, new uses currently cannot be authorized before a comprehensive review of the existing MRLs has been performed. EFSA also notes that for a future MRL application it would be necessary to provide background information on the existing EU MRLs (GAPs, residue trials, processing studies) which would be required to make a more accurate estimation of the long-term exposure resulting from the existing uses and to derive a sound conclusion on the safety of new MRLs for diquat.
