Study of pesticide residues in agricultural products towards the "Positive list" system

During a 3-year monitoring survey (April 2002-March 2005) of pesticide residues in agricultural products, 592 samples (324 domestic; 268 imported) collected in Hyogo prefecture, Japan were analyzed. The number of pesticides tested increased from 232 in FY 2002 to 323 in FY 2004. The purpose of the study was to clarify the residue status by accumulating information about pesticides detected frequently, to allow effective and efficient regulation under the new "Positive List" legislation to be implemented in FY 2006. Overall, 47% of domestic and 61% of imported samples contained detectable residues and ca. 60% of positive samples contained multiple residues. The limit of quantitation was set at 0.01 mu g/g and the limit of detection was 0.001-0.003 mu g/g. Most of the residues were present at low concentrations: 80% of the detections in samples excluding imported citrus fruits were < 0.05 mu g/g. More than 5 different pesticides (> 0.01 mu g/g) were detected simultaneously in 13 samples. The sum of the ratios of residues to MRLs was calculated as one of the indexes to represent the risk of multiple residues, and they exceeded 100 % in 3 imported frozen vegetables; baby kidney bean, spinach, Welsh onion. Samples in violation of the Food Sanitation Law were not found in our survey, but 1.9% of the samples might be in conflict with the new "Positive List" legislation.