IMEP-34: Heavy Metals in Toys according to EN 71-3:1994

Abstract

The Institute for Reference Materials and Measurements (IRMM) of the Joint Research Centre (JRC), a Directorate-General of the European Commission, operates the International Measurement Evaluation Programme (IMEP). It organises interlaboratory comparisons (ILC's) in support to EU policies. This report presents the results of an ILC which focussed on the determination of soluble antimony (Sb), arsenic (As), barium (Ba), cadmium (Cd), chromium (Cr), lead (Pb), mercury (Hg), and selenium (Se) according to European Standard EN 71-3:1994. The principle of the procedure in EN 71-3:1994 [1] consists in the extraction of soluble elements from toy material under the conditions simulating the material remaining in contact with stomach acid for a period of time after swallowing. Fifty eight participants from twenty six countries registered to the exercise, of which 54 reported results for As, Sb, Ba, Se and Hg and 58 for Cr, Pb, and Cd, respectively. The test item used was a certified reference material (CRM 623, comminuted paint flakes from alkyd resin paint), certified in 1998, which is not included anymore in the CRM catalogue. The validity of the certified values was assessed using some expert laboratories in the field. In most of the cases the results reported by the certifiers were not in agreement with the CRM reference values. The mean of the means reported by the expert laboratories was used as assigned value for the different measurands. The results reported by the expert laboratories for mercury were very scattered (RSD = 37.6 %). No assigned value could be attributed for mercury and therefore no scores were provided to the participants for this measurand. The associated uncertainties of the assigned values were obtained following the ISO GUM. Furthermore, participants were invited to report their measurement uncertainties. This was done by all laboratories having submitted results in this exercise. Laboratory results were rated with z- and zeta (ζ-) scores in accordance with ISO 13528. The standard deviations for proficiency assessment were based on the analytical correction laid down in EN 71-3:1994. The outcome of the exercise shows an improvement on the overall performance of the participants when compared to IMEP-24 (a proficiency test for heavy metals in toys run in 2009 in which, the same European standard was followed), particularly for cadmium, lead and to a lesser extent, for selenium and chromium. The share of satisfactory z-scores ranged from 65 to 79 %.JRC.D.5-Food Safety and Qualit