Assessment of pesticide exposure pathways on humans in Mang'ola ward, Karatu district-Arusha, Tanzania

Abstract

A cross-sectional study was carried out in Mang’ola area in Lake Eyasi basin from October 2012 to February 2013 to assess pesticide exposure pathways to vegetable growers and consumers. A total sample size of 263 respondents was selected for the study. Baseline data for exposure pathway scenario, eating habits and quantities of vegetables consumed were collected using structured questionnaires, In-depth interview, Focus group discussion and observations. Health risk characterization was estimated based on FAO/WHO guidelines. Results showed an indiscriminate use of pesticides with limited knowledge on environmental contaminants and public health risks. About 61% of vegetable growers who applied pesticides once pests appeared on their grown vegetables, only 4.9% consulted the Agriculture Extension Officers. Up to 75.6% of vegetable growers mixed more than two types of pesticides and did not abide to basic safety procedures for pesticide application. Also 73.2% of pesticide applicators were not used personal protection devices. Ingestion of contaminated vegetables as the route of pesticide exposure to consumers had 53.7% and most consumed vegetables were onions and tomatoes (97.6%). Among the identified exposure pathways from pesticide contaminated fields were “take-home pathway”, “residential proximity pathway” and “contaminated wind spray drift exposure pathway” associated with direct dermal contact (68%) and inhalation (54%). Secondary retrieved pesticide residue concentrations data ranged from <0.01 to 18.10 mg/kg, those were organophosphates, organochlorines, pyrethroids, triazole and Triadimefonog-menol. The highest health indices were found for pyrethroids (0.96 ≈1) and organophosphate (5.9). Therefore, health hazards were by organophosphate since their Hazard Risk Index level exceeded 1, while pyrethroids level was likely to cause risk to exposed consumers. Most of the previous studies ended up with hazard identification and characterization but this study addressed exposure