Browsing by Author "Kapeleka, Jones"

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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.
Biomonitoring of pesticides exposure and the fate of pesticides use among smallholder vegetable producers in Tanzania
(NM-AIST, 2020-08) Kapeleka, Jones
This study assessed drivers of increased and changing patterns of pesticide use, levels of Acetylcholinesterase (AChE) inhibition, associated health effects and co-exposure risks of pesticide residues and bacterial contaminants in fresh vegetables. A total of 613 vegetable samples were collected from Arusha, Kilimanjaro, Manyara, Dar es Salaam, Morogoro and Iringa, regions. Binary probit models were used to analyze factors fostering increased pesticide use, determinants of pesticide exposure and risks of co-exposure. Significant results were accepted at p < 0.05. Results revealed that most farmers (88.9%) were unaware of pesticide safety practices. Compared with previous studies, there was increased trend in pesticide use (58.4%), which was accompanied by changing pesticide formulations. The number of crops grown (p = 0.002), pesticide mixing (p = 0.012) and region (p = 0.001) contributed positively to likelihood for increased pesticide use. Smallholder farmers were found to be occupationally exposed to pesticides, where exposed farmers had significantly lower AChE levels. The number of exposure symptoms (14.10±7.70) was higher in exposed than unexposed farmers. Self-reported symptoms were also confirmed to correlate with lower AChE and the use of personal protective equipment did not significantly reduce exposure. Women, younger and older farmers, underweight, overweight, and obese farmers were at increased risk of pesticide exposure. Moreover, locally produced fresh vegetables were highly contaminated with pesticide residues, 47.5% had detectable levels of pesticide residues, 74.2% of which recorded average residue levels above Codex Maximum Residue Levels (MRL) standards. Multiple pesticide residues were also detected, these included organophosphates (95.2%), organochlorines (24.0%), pyrethroids (17.3%) and carbamates (9.2%), all constituting the main detected pesticide residues. Consequently, bacterial contamination of fresh vegetables was also evident, with prevalence of bacterial contamination being 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. 46.4% of tested samples were positive for both pesticide residues and bacterial contaminants. Vegetables from farms (60.7%) contained more bacterial contaminants while vegetables with pesticide residues were about twice more likely to be contaminated with bacteria (OR: 2.231; 95% CI: 0.501, 8.802). Findings from this study also showed extensive use of pesticides, bacterial contamination and exposure among small holder farmers. The observed exposure risks pose short and long-term effects on health of both farmers and general population. The contamination levels of pesticide residues and bacterial contaminants could also be perceived as a serious health problem, as most fresh and vegetables recorded values of pesticide residues far above the Maximum Residue Limits (MRLs) with pathogenic bacteria isolated in higher proportions. Maximum Residue Limits were higher in most vegetables that were consumed raw or semi-cooked. There is therefore an urgent need to develop pesticide monitoring and surveillance systems at farmers’ level by educating farmers and promoting the use of greener pesticides to mitigate the health effects of pesticides and bacterial contaminants.
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.
Pesticide exposure and genotoxic effects as measured by DNA damage and human monitoring biomarkers.
(Taylor & Francis online, 2019-11-18) Kapeleka, Jones; Sauli, Elingarami; Ndakidemi, Patrick
Occupational pesticides exposure rises health concern due to genotoxicity and accumulation of pesticides in human biological matrices. Continuous and sublethal exposure to pesticides had been associated with oxidative stress, mutagenic and cell death. Exposure to pesticides exhibits increased level of DNA damage even if no detectable amounts of pesticides are seen in biological matrices by binding specific areas in the DNA. This interferes normal body systems and mutation in gene encoding specific activities which may lead to a wide range of cancer. Presence of pesticides compounds in human biological matrices had been evident from various studies. However, detection methods are complex and inconsistent, making it difficult to compare and generalize findings. This article provides insight into genotoxic effects, presence of pesticides and their metabolites in human biological matrices and the resultant health effects as measured by DNA damage, acetylcholinesterase (AChE) activity inhibition and other biomarkers of pesticides exposure.