Dithiocarbamates residues in Brazilian food and the potential risk for consumers.

Dithiocarbamates are a non-systemic group of pesticides widely used to protect crops from fungal diseases. The current methodology used by monitoring laboratories to determine dithiocarbamates in food involves the analysis of CS(2) generated after hydrolysis of the compound present in the sample. This method does not identify the origin of the CS(2) detected, which may or may not be related to the presence of pesticides leading to a potential overestimation of the dietary dithiocarbamate intake. In this paper, 520 food samples (papaya, banana, apple, strawberry, orange, potato, tomato, rice and dry beans) collected in the local market of the Federal District, Brazil, were analyzed for dithiocarbamate content. Detectable levels (> or =10.10 mg/kg CS(2)) were found in 60.8% of the samples, with the highest levels (up to 3.8 mg/kg) found in strawberry, papaya and banana. No residues were found in rice (polished) and only one dry bean sample had detectable levels of the fungicides. Detectable residues were found in the pulp of banana, papaya (including the seeds) and orange (50-62% of the analyzed samples). An exposure assessment, based on dithiocarbamate levels detected in the food crops analyzed in this study, confirms that the intake of dithiocarbamates through food consumption in the country does not represent a health risk to consumers, i.e., the estimated daily intake is less than the acceptable daily intake. Furthermore, the implementation of more selective methodologies to individually analyze these compounds in food monitoring programs in Brazil is not necessary.

Determination of dithiocarbamate fungicide residues in food by a spectrophotometric method using a vertical disulfide reaction system.

Dithiocarbamates are a class of fungicides extensively used in many crops worldwide. The current residue definition of dithiocarbamates in food for compliance with maximum residue limits, at national and international levels, is total residues arising from the use of any or each dithiocarbamate fungicide, determined as CS(2). The analytical method most frequently used to analyze dithiocarbamate residues in food for monitoring purposes was proposed more than 30 years ago. In this method, total dithiocarbamates are decomposed to CS(2), which is purified and reacted with a cupric reagent. The yellow complex formed is quantified by spectrophotometry. In this paper, a new reaction system for the purification and complexation of CS(2) is proposed. The new system is less fragile than the traditional design, is easier to assemble, and allows for a higher sample throughput, in addition to being of low cost. Recovery of added mancozeb, thiram, or ziram (0.15-8.0 mg/kg) in rice, beans, apple, banana, orange, papaya, tomato, cucumber, and potato ranged from 82 to 120%, with relative standard deviations from 0 to 10% (n = 3 or 5). Analysis of apple, tomato, and papaya samples with field-incurred dithiocarbamate residues showed comparable results using both the traditional and the new reaction systems.