Über unsResidues of the unauthorized insecticide isofenphos-methyl detected in sweet peppers from Spain
Background
and summary
Residues of the insecticide isofenphos-methyl, which is not authorized in the EU, were detected in sweet peppers from Spain. In total, 35 samples of sweet peppers from different origins were analysed for the presence of this pesticide since mid-November: in 9 of 15 (60%) of the Spanish samples isofenphos-methyl was detected, whereas in 6 of these samples (40%) the residues were above the maximum residue level of 0,01 mg/kg. In samples of other origins than Spain (Turkey, The Netherlands, Morocco) isofenphos-methyl was not detected.
Legal situation and authorisation status
According to the present information, a plant protection product containing isofenphos-methyl is neither authorized in Spain nor in any other EU Member State. Thus, the active agent isofenphos-methyl is not included in Annex 1 of the Council Directive 91/414/EEC, and no appraisal for an authorisation is currently scheduled.
To our best knowledge, isofenphos-methyl is most likely produced in China and imported and applied illegally in Spain, and thus without any toxicological risk assessment.
The German Federal Institute for Risk Assessment (Bundesinstitut für Risikobewertung, BfR) stated that no data on the toxicity of the active agent isofenphos-methyl is currently present in relevant literature. A toxicological assessment of the detected residue levels is therefore at present not possible. But, isofenphos-methyl belongs to the group of neurotoxic phosphoric acid esters and the chemically very similar active agent isofenphos (= isofenphos-ethyl) exhibits with a very low ADI of 0,001 mg/kg (BfR 1992, WHO 1986) a comparably high toxicity. Thus, a similar toxicological relevance has to be considered for isofenphos-methyl. Therefore, for samples with higher levels of isofenphos-methyl, a health risk can’t be excluded with required certainty.
Analysis
Since no analytical standard of isofenphos-methyl was available, the quantification was performed elaborately using the chemically similar substance isofenphos via gas chromatography - mass spectrometric methods in combination with selective detectors (NPD). The CVUA Stuttgart arranged the synthesis of a certified standard (now available from Sigma-Aldrich: Riedel-de Haën Pestanal 50 mg Art. No. 33436).
Detailed guidelines for the sample preparation (QuEChERS method) are presented on the internet (www.quechers.de). The mass spectra for isofenphos-methyl and isofenphos can be uploaded under the following links:
Mass spectrum of isofenphos [PDF, 112 KB]
Mass spectrum of isofenphos-methyl [PDF, 111 KB]
GC/NPD chromatogram of isophenphos and isofenphos-methyl [PDF, 29 KB]
Detailed report of the results
In November and December, the CVUA Stuttgart analysed 35 samples sweet peppers from 4 different origins for pesticide residues. 15 samples were from Spain, 10 from Turkey, and 5 from Morocco and The Netherlands each (see diagram 1).
Diagram 1: number and origin of samples analysed November/December 2006
Residues of the insecticide isofenphos-methyl were exclusively detected in samples from Spain, here in 9 samples (60% based on samples from Spain). Whereas in 6 of these samples the residues were above the maximum residue level of 0,01 mg/kg (40% based on samples from Spain). In the other 3 samples, residues of isofenphos-methyl £ 0,01 mg/kg were detected. In table 1 the individual results of the sweet peppers from Spain are displayed.
Table 1: isofenphos-methyl results in sweet peppers from Spain in Nov./Dec. 2006
| sample | origin | isofenphos-methyl (mg/kg) | evaluation of result | |
| sweet pepper | Spain | 0,1 | MRL violation | |
| sweet pepper | Spain | 0,01 | below MRL | |
| sweet pepper | Spain | <LOQ | ||
| sweet pepper | Spain | 0,035 | MRL violation | |
| sweet pepper | Spain | 0,046 | MRL violation | |
| sweet pepper | Spain | nd | ||
| sweet pepper | Spain | <LOQ | ||
| sweet pepper | Spain | 0,025 | MRL violation | |
| sweet pepper | Spain | nd | ||
| sweet pepper | Spain | 0,067 | MRL violation | |
| sweet pepper | Spain | 0,023 | MRL violation | |
| sweet pepper | Spain | nd | ||
| sweet pepper | Spain | 0,008 | below MRL | |
| sweet pepper | Spain | nd | ||
| sweet pepper | Spain | 0,005 | below MRL | |
MRL: maximum residue level <LOQ: below limit of quantification nd: not detectable |
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