Ethylenethiourea in fruits

Abstract

Ethylenethiourea (ETU) is a toxicologically relevant degradation and/or biotransformation product of fungicides ethylenebisdithiocarbamates, that should be considered in a consumer risk assessment. The aims of this research were the validation of a method for analysis of ETU in fruits by liquid chromatography tandem mass spectrometry, the evaluation of ETU occurrence in fruits and ETU and dithiocarbamates dietary exposure assessment. The validated method was fitness for the purpose. Linearity was demonstrated between 1 and 25 ng/mL, without matrix effects. Recovery averages ranged from 75 to 110% for spiked samples at 1.0, 2.0 and 10.0 mg/kg, with relative standard deviation from 5 to 17%, indicating trueness and precision. The limits of detection and quantification were 0.5 and 1.0 mg/kg, respectively. Ninety samples of apple, papaya and strawberry were collected from different regions of São Paulo city and over all seasons of the year. ETU residues were found in 32 (35%) samples with levels ranging from 1.0 to 5.3 mg/kg. The exposure assessment to evaluate the health risk by eating fruit with ETU residues corresponded, respectively, for adults, teenager and children 0.05, 0.05 and 0.09% of the acceptable daily intakes (ADI) and 0.9, 1.1 and 1.6% of the oral dose for chronic non-carcinogenic effects. The contribution to the risk by consumption of food containing residues of dithiocarbamates, whereas the highest values found in the products monitored by the national Program in the period from 2001 to 2010 and the per capita food acquisition for urban population, represented 19.2% of the ADI (Mancozeb) for adult, 22.8% for teenager and 34.0% for children.