Measuring exposure to strobilurin fungicides in strawberries, grapes, and spinach: Does washing the produce make a difference?

Abstract

Consumption of foods containing pesticide residues is one of the major pathways by which people are exposed to pesticides. Fungicides are an important class of pesticides, and previous research indicates that not only are certain fungicide application rates increasing, but also fungicide residues on produce can be relatively high on some produce, such as berries, leading to potential health concerns. Attention to strobilurin fungicides, a relatively new class of fungicides, in particular has been growing due to their widespread application, potential toxic effects on metabolic processes, and concerns that exposure may be a risk factor for neurodegenerative diseases. This study aimed to quantify potential exposure to four strobilurins (azoxystrobin, fluoxastrobin, pyraclostrobin, and trifloxystrobin) and to determine whether fungicide residues on certain produce items were considered a health risk. Furthermore, this research sought to determine if different washing techniques could reduce exposure and, therefore, risk. Exposure was evaluated by purchasing organic and generic varieties of grapes, strawberries, and spinach from three local grocery stores in Durham, North Carolina. The effect of two different produce washing treatments was evaluated by comparing residue concentrations on produce samples that were either rinsed with cold tap water or washed with a commercial produce detergent. Results demonstrate that pyraclostrobin and trifloxystrobin were the most commonly detected of the four strobilurin compounds monitored. Organic varieties had residue levels that were below the method detection limit. On average, residue levels were 18.07 ng/g pyraclostrobin and 15.01 ng/g trifloxystrobin on generic strawberries, and 19.6 ng/g pyraclostrobin and 0.4 ng/g trifloxystrobin on generic grapes. None of the four strobilurin fungicides were detected above trace levels in the spinach samples tested. For strawberries, tap washing removed approximately 52% of trifloxystrobin residue and the Ecos produce detergent removed 45%; for grapes, tap washing removed 72% of pyraclostrobin residue and the Ecos produce detergent removed 83%. Using the maximum amount detected in this study, exposure estimates were calculated for an average adult and child and compared with the acute and chronic reference doses. Overall, hazard quotients were less than one, indicating that exposure to fungicides from consumption of these items is less than the reference doses established by the US EPA, suggesting minimal to no risk.