Modelling the behavior of pesticide residues in tomatoes and their associated long-term exposure risks

Abstract

This study is focused on the dissipation behavior of 7 fungicides and 5 insecticides applied in tomatoes after a third spraying at recommended and double doses by considering 6 kinetic models which allow estimating the pesticides half-lives (t_1/2). Except studying the pesticides dissipation, another scope of our manuscript was investigating the risk to human health after application of different pesticide treatments in tomatoes. The pesticides analysis in tomatoes at harvest showed that the residues were below the maximum residue level (MRL), with the exception of chlorotalonil (included in Group 2B - "Possibly carcinogenic to humans") and bifenthrin for recommended dose treatments, while for double dose treatments, the MRLs was exceeded for 7 pesticides, once again including chlorotalonil. For recommended dose treatments, the 1st order kinetic model is confirmed only for metalaxyl-M. The values of pesticides t_1/2 ranged from 0.006 days (for chlorothalonil) to 48.59 days (for myclobutanil). For double dose treatments, the 1st order kinetic model is confirmed for deltamethrin and triadimenol. In this case, the values of pesticides t_1/2 ranged from 0.32 to 10.67 days. Further, consumers' exposure was estimated by calculating the long-term risk based on hazard quotient (HQ). The results indicated that the risks generated by pesticide residues in tomatoes applied in recommended or double doses are in an acceptable limit, except for chlorothalonil which may pose a threat for children health. However, if we consider the cumulative hazard index (HI) values which were higher than 1, consumption of tomatoes containing pesticides residues may cause harmful non-carcinogenic health effects.

Keywords: Chlorothalonil; Dissipation; Human health risk assessment; Kinetic modelling; Tomatoes.