Browsing by Author "Sadik, Omowunmi"

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Biomonitoring of Acetylcholinesterase (AChE) Activity among Smallholder Horticultural Farmers Occupationally Exposed to Mixtures of Pesticides in Tanzania
(Hindawi, 2019-09-11) Kapeleka, Jones; Sauli, Elingarami; Sadik, Omowunmi; Ndakidemi, Patrick
Biomonitoring of pesticides exposure has currently become a matter of great public concern due to the potential health effects of pesticides. ,is study assessed levels of acetylcholinesterase (AChE) inhibition and associated health effects in uncontrolled smallholder farming systems in rural Tanzania. A cross-sectional study was conducted of 90 exposed farmers and 61 nonexposed controls from horticultural zones. A structured questionnaire was administered, and a capillary blood sample of 10 μl was used to measure AChE activity using an Erythrocyte Acetylcholinesterase Test Mate Photometric Analyzer kit (Model 400). A multiple logistic regression model was used to investigate determinants of pesticide exposure. ,e study revealed that smallholder farmers are occupationally exposed to pesticides. Exposed farmers had significantly lower AChE levels. ,e use of personal protective equipment (PPE) did not significantly reduce the likelihood of AChE inhibition. Women, younger and older farmers, and underweight, overweight, and obese farmers were at increased risk of AChE inhibition. Increase in age (10 years) increased likelihood of AChE inhibition by 6.7%, while decrease in BMI increased likelihood of AChE inhibition by 86.7% while increased pesticides contact hours increased risk of having lower AChE at about 3 times. ,e number of exposure symptoms (14.10 ± 7.70) was higher in exposed farmers than unexposed. Self-reported symptoms are confirmed to correlate to lower AChE. Prevalence of tiredness (71.6% against 15.5%), fatigue (64.8% against 27.6%), soreness in joints (59.1% against 20.7%), thirst (52.3% against 12.1%), skin irritation (52.1% against 17.2%), salivation and abdominal pain (50% against 8.6% and 31.0%, respectively), muscle weakness (47.7% against 24.1%), and memory loss (47.7% against and 29.3%) differed significantly between exposed and control. ,is study provides useful information regarding the level of occupational and environmental exposure to pesticides in smallholder horticultural production systems. Pesticides use needs to be controlled at farm level by developing pesticides monitoring and surveillance systems.
Changing Patterns and Drivers of Increased Pesticides Use in Smallholder Vegetable Production Systems in Tanzania
(BioRxiv, 2021-01-18) Kapeleka, Jones A.; Sauli, Elingarami; Sadik, Omowunmi; Ndakidemi, Patrick A.
Pesticides use has become a key component of smallholder horticulture production. Therefore, dynamics in pesticides handling need to be ascertained. This study assessed drivers of pesticides use and determinants of changing patterns of pesticides handling practices in smallholder vegetable systems. Data were collected from 385 farmers from Iringa, Arusha, Manyara, and Kilimanjaro regions in Tanzania through an in-depth survey and field observations. A binary probit model was used to derive factors fostering increased pesticides use. Results showed that 47.9 % of all pesticides were wrongly used. Most farmers (88.6%) lacked knowledge of pest control and 88.9% were unaware of safety practices. Disposal methods of empty pesticides foster occupational and environmental exposure (58%). There was an increasing trend in pesticides use (58.4%), accompanied by changing pesticides formulations. Over 60 pesticides with 29 different formulations were used. Mixing pesticides (71.2%), high dose rates with increased frequency of application were observed. Pesticides under Class II WHO hazard (68.9%) dominated. Extremely hazardous (Class Ia) and highly hazardous (Class Ib) were also used. Binary probit model showed that number of crops grown, pesticides mixing, and region contributed positively to the likelihood of increased pesticides use while farmers’ perception of effectiveness of pesticides, lack of access to safe use information, poor use of safety gears and inability to read pesticides labels had a negative impact. The fate of pesticides use in smallholder vegetable production systems is therefore the culmination of serious health and environmental implications. Excessive pesticides use escalated by increased number of crops, improper use of PPE, and pesticides mixing practices subjects the general population to pesticides environmental exposure thereby jeopardizing sustainability of smallholder vegetable production in Tanzania. Regular training to farmers and extension officers on current and emerging issues on pests and pesticide safe use is vital.
Co-exposure risks of pesticides residues and bacterial contamination in fresh fruits and vegetables under smallholder horticultural production systems in Tanzania
(PLOS ONE, 2020-07-25) Kapeleka, Jones; Sauli, Elingarami; Sadik, Omowunmi; Ndakidemi, Patrick
This study was carried out to investigate the risks of simultaneous exposure to pesticide residues and bacteria contaminants in locally produced fresh vegetables and vegetables in Tanzania. A total of 613 samples were analyzed for pesticide residues, out of which 250 were also analyzed for bacterial contamination. Overall, 47.5% had pesticide residues, 74.2% exceeded Maximum Residue Levels (MRLs). Organophosphorus (95.2%), organochlorines (24.0%), pyrethroids (17.3%), and carbamates (9.2%) residues dominated. MRL values were mostly exceeded in tomatoes, onions, watermelons, cucumbers, Chinese cabbage, and sweet paper. Tetramethrin (0.0329–1.3733 mg/kg), pirimiphos-methyl (0.0003– 1.4093 mg/kg), permethrin (0.0009–2.4537 mg/kg), endosulfan (beta) (0.0008–2.3416 mg/ kg), carbaryl (0.0215–1.5068 mg/kg), profenofos (0.0176–2.1377 mg/kg), chlorpyrifos (0.0004–1.2549 mg/kg) and dieldrin (0.0011–0.5271 mg/kg) exceeded MRLs. The prevalence of bacteria contamination was high (63.2%). Enterobacter (55.6%) Pseudomonas aeruginosa (32.4%), E. coli (28.2%), Citrobacter (26.8%), Klebsiella oxytoca (14.8%), and Salmonella (7.7%) were isolated. Furthermore, 46.4% tested positive for both pesticide residues and bacterial contaminants. Vegetables from farms (60.7%) contained more dual contaminants than market-based vegetables (41.8%). This may have resulted from excessive pesticide use and unhygienic handling of fresh fruits and vegetables at production level. Binary logistic regression showed that fresh fruits and vegetables with pesticide residues were 2.231 times more likely to have bacteria contaminants (OR: 2.231; 95% CI: 0.501, 8.802). The contamination levels of pesticide residues and bacterial contaminants could be perceived as a serious problem as most fresh fruits and vegetables recorded values of pesticide residues far above the MRLs with pathogenic bacteria isolated in higher proportions. MRLs was higher in most vegetables consumed raw or semi-cooked such as watermelons, carrots, cucumber, tomatoes, onion and sweet paper. There is an urgent need to develop pesticide monitoring and surveillance systems at farmer level, educating farmers and promoting the use of greener pesticides to mitigate the health effects of pesticides and bacterial contaminants.