Human and environmental exposure to pesticides in uganda: insights from water, food and human urine assessments

Abstract

Human and Environmental Exposure to pesticides in Uganda: Insights from water, food and human assessmentsAuthor: Atuhaire Aggrey; atuagrey3@gmail.com Uganda National Association of Community and Occupational Health (UNACOH), Kampala, UgandaBackground In Uganda, there is limited data on human pesticide exposure and residue assessment. Between 2017 and 2019, Uganda National Association of Community and Occupational Health (UNACOH) in collaboration with its partners undertook different studies with an overall aim of assessing residue levels in community water sources, tomatoes, and exposure levels in farmers’ urine. MethodologyTomato samples were collected from farms and markets were subjected to three pre-treatments of cold wash, warm wash, peeling and compared with the control. Water samples were gathered at the start and end of a cropping season. Farmers were assessed for Mancozeb exposure at two time points (588 samples) and a questionnaire-based exposure algorithm generated. Results94.2% of the water sources had detectable pesticide residues. 25 pesticides were detected, with the number increasing by 3.6 fold between the start and end of season. Glyphosate was detected in highest concentrations levels. 6/10 most concentrated pesticides were detected in proportions exceeding maximum limit of 0.1ppb in 53 water points.Eight pesticides were detected in the tomato samples. Mancozeb was detected in highest concentration levels. The different processing techniques reduced residue levels, peeling being the most effective. About 29% of unprocessed tomato samples exceeded the Codex MRL of 2ppm for Dithiocarbamates.98% of all samples measured above LOD of 0.08 ng/mL. Farmers who reported applying Mancozeb in the last one week registered a median of 14.6 (IQR 6.7-33.5) μg/g creatinine.ConclusionCommunity water pollution from conventional farming is a public health threat in Uganda. Mancozeb use poses a threat to Uganda’s agricultural export market and public health.