RESUMEN
This study assessed pesticide usage practices, knowledge and health effects of pesticides through occupational exposure in randomly selected horticultural farmers in Imenti North, Imenti South and Buuri Sub-counties in Meru, Kenya, where horticultural crops are grown intensively for export and local consumption. The study was done through use of questionnaire distributed to farmers' households, agricultural extension workers and health care workers. The survey established that various classes of pesticides were used in horticultural crop farming and animal production in all the three sub-counties, with the most frequently used (>60 respondents out of 173) being parathion, diazinon, dimethoate, permethrin, pirimiphos methyl, endrin, deltamethrin, dieldrin, propoxur and endosulfan. It was found that there is a gap between the existing government regulations on pesticide use and safe handling and the implementation of these regulations by dealers, farmers and farm workers in the three sub-counties as some of the pesticides that were being used such as parathion, endrin, dieldrin and carbofuran had been banned by the government. Although most farmers had general information on pesticide usage through various social groups and contact with agricultural extension workers, only 32-43 % of the farmers had received training on pesticide handling and use. Most farmers (65%) had knowledge of safe pesticide handling procedures including reading labels on packages and wearing protective clothing; but many farmers (44% in Buuri, 57% in Imenti South and 60% in Imenti North) did not wear the requisite protective clothing when applying pesticides. The agricultural extension workers (52%) and health care workers (59%) were trained in their work and had at least a certificate level qualification from a tertiary institution. Most agricultural extension workers (95%) and health care workers (71%) had experience of dealing with pesticides and knew how to administer 1st AID against pesticide poisoning, respectively. Farmers (26%) reported experiencing health effects after using pesticides, with most effects being felt after using dimethoate, malathion, carbofuran, carbaryl and heptachlor. There was a statistically significant (p < 0.05) association between various factors (availability of protective clothing, hiring of labourers, farm land size, expenditure on pesticides and expenditure on treatment, respectively) on intoxication from pesticide exposure.
RESUMEN
Residue levels of seven commonly used pesticides were determined in random samples of tomatoes, French beans, and kale collected from horticultural farms in Buuri, Imenti North, and Imenti South sub-counties in Meru, Kenya, just before delivery to the consumers. QuEChERS method for extraction followed by LC-MS/MS was used to determine the concentrations. The concentrations (µg kg-1 wet weight) in French beans, kale, and tomatoes ranged from below detection limit (BDL): BDL-48.65 (carbendazim), BDL-290.76 (imidacloprid), BDL-2.81 (acetamiprid), BDL-25.76 (azoxystrobin), BDL-105.18 (metalaxyl), BDL-0.15 (diazinon), and BDL-0.17(chlorpyrifos). The maximum residue levels determined in the horticultural produce from the three regions were 290 µg kg-1 for imidacloprid in tomatoes from Buuri and 25.76 µg kg-1for azoxystrobin in French beans from Imenti South. The pesticide residue levels generally were extremely low and met the MRLs set by EU and other countries, except for carbendazim and metalaxyl in French beans, and posed no concern to human health. The estimated daily intakes (EDI) (mg kg-1 BW/day) for the population of Meru County were very low ranging from 1.685 × 10-8 (acetamiprid) to 2.381 × 10-5 (imidacloprid) in tomatoes, 2.849 × 10-9 (metalaxyl) to 3.633 × 10-7 (azoxystrobin) in French beans, and 1.392 × 10-8 (diazinon) in kale, respectively. The health risk indices were subsequently extremely low for the detectable pesticide residues, ranging from 6.74 × 10-7 (acetamiprid) to 3.97 × 10-4 (imidacloprid) in tomatoes, 3.56 × 10-8 (metalaxyl) to 5.52 × 10-5 (chlorpyrifos) in French beans, and 6.96 × 10-5 (diazinon) in kale, respectively, indicating no health risk in the population, but their presence in these vegetables cannot be ignored as long-term exposure can still cause health risks.