Life cycle human exposure and risk assessment of pesticide application in Colombia: The example of potatoes

Although the human health effects of pesticides have decreased, chronic health problems are still significant in many developing countries and emerging economies. In this project we examined the various exposure pathways of pesticide application over the whole life cycle of potatoes grown in Colombia. Exposure pathways included e.g. workers' exposure during pesticide preparation and application and consumer exposure by ingestion of the pesticide-treated crops. A dynamic model was developed for pesticide crop uptake and evaluated with measurements performed within a field trial in the region of Boyacá, Colombia. Pesticide concentrations were measured periodically in soil and potato samples from the beginning of tuber formation until harvest. The model was able to predict the magnitude and temporal profile of the experimentally derived pesticide concentrations well, with all measurements falling within the 90% confidence interval. Pesticides residues in potatoes were rather low and below health-based threshold values in the case investigated. However, the study was performed in an unusually dry year with smaller amounts of fungicides applied than in other years. Therefore, to study exposure and risk in the region under normal circumstances, an enquiry about pesticide use was conducted among 79 farmers of the region and the model applied to the application pattern of pesticides reported by the farmers. Results show that substitution of a few active ingredients could lower consumer exposure significantly. With regard to workers’ health, dermal exposure was found to be enhanced in only several cases. Several measures are suggested to lower workers’ exposure. Finally, human intake of pesticides was quantified and compared throughout the life cycle of potatoes. Cumulated intake fractions of consumers’ ingestion and farmers’ dermal exposure were comparable, but individual doses for farmers were much higher and above no-effect-levels. This highlights that individual risk assessment studies are needed in addition to LCA, which typically cumulates intake.