Pesticide residues on fruits and vegetables from Ontario, Canada, 1991-1995

For the 5-year period 1991 to 1995, 1536 vegetable and 802 fruit samples we re analyzed, The purpose of this study was to determine if pesticides were present on Ontario-produced fruits and vegetables, and if so, to determine if residues violated maximum residue limits (MRLs), Overall, 31.5% of the s amples had no detectable pesticide residues, whereas 68.5% contained one or more residues. Most of the residues were present at very low concentration s; 48% of the detections were <0.1 parts per million (ppm), and 86% were <1 ppm, However, violations of MRL were observed in only 3.2% of the vegetabl e samples and 3.1% of the fruit samples. In addition, 4.8% of the samples c ontained a "technical" violation, that is, there was no specified MRL for t he pesticide-commodity combination and the residues exceeded 0.1 ppm. Of th e detectable residues, 63% were <10% of the MRL, whereas 89% were <50% of t he MRL, More fruit samples (91.4%) had a detectable residue, compared with vegetable samples (56.6%). Fruit is often treated close to harvest or post harvest to ensure that wholesome produce reaches the consumer. Forty-six pe rcent of the samples contained 2 or more residues, and 2% of all samples ha d more than 5 different pesticides detected; fruit samples tended to have m ore multiple residues. The most frequently found pesticides were captan, th e dithiocarbamate fungicides, endosulfan, azinphos-methyl, phosmet, parathi on, and iprodione, These pesticides were also used in the greatest quantity for crop production. Overall, the data agree fairly closely with those rep orted for the U.S. Department of Agriculture Pesticide Data Program because the 2 programs have similar analytical goals and objectives.