Contamination of Foods from Cameroon with Residues of 20 Halogenated Pesticides, and Health Risk of Adult Human Dietary Exposure.

(1) Background: Halogenated pesticides are abundantly used in Cameroon, but there is no information on the health risk of consumers from exposure to their residues in foods. (2) Methods: Residues of 20 halogenated pesticides were determined in 11 agricultural products collected in the 3 largest cities of Cameroon using QuEChERS extraction and gas chromatography with electron capture detector (GC-ECD), and health risk from dietary exposure was assessed. (3) Results: Organochlorines pesticides aldrin, p,p'-dichlorodiphenyl-trichloroethane (DDT) and ß-hexachlorocyclohexane (ß-HCH) found in 85.0%, 81.9% and 72.5% of samples, respectively, were the most frequently detected. The highest average concentrations of residues were 1.12, 0.74 and 0.39 mg/kg for methoxychlor, alachlor and ß-HCH, respectively, found in chilli pepper. Chili pepper (58.9%), cowpea (56.8%), black beans (56.5%) and kidney beans (54.0%) exhibited the highest residue occurrences. Levels above the European Union maximum residue limits (MRLs) were found for all the 20 pesticides, in 40.1% of the positive analyses, and the food samples contained 14 pesticides banned in Cameroon. Chronic, acute, cumulative and carcinogenic risk assessments revealed that lifetime consumption of maize, black beans, kidney beans, groundnuts and chili pepper contaminated with aldrin, dieldrin, endrin, HCB, heptachlor, o,p'-DDT, p,p'-DDD, p,p'-DDT, p,p'-DDE and ß-HCH, could pose health risks. (4) Conclusion: These results show that there is an urgent need of pesticide usage regulation, effective application of pesticide bans and management of obsolete pesticide stocks in Cameroon.

Pesticides residues in tobacco smoke: risk assessment study.

Pesticides are not only used on food but also on non-food crops, such as tobacco, to control a range of unwanted animal, plant, and microbial, fungal pests. The residue levels in tobacco leaves are expected to decline up to harvest, during drying, and when the leaves are further processed. Additional pesticides may also be applied to the finished product and residue levels may remain present even when the tobacco is burned. Human exposure to pesticide residues on tobacco occurs when residues remaining in cigarette smoke are inhaled. Based on this assumption, the objectives of this research were (i) to determine the level of pesticides residues in harvested tobacco leaves and (ii) to assess the risk of human exposure to these residues in tobacco smoke. Pesticide residues were detected in all analysed tobacco samples. These detected residues represent ten different active ingredients (AI), three of these AIs (thiodicarb, alachlor, and endosulfan) are no longer allowed in Europe. A 54.7% of these residues were quantifiable. Furthermore, it was found that with the use of solid-phase extraction sorbent (SPE) as adsorbent and n-hexane as solvent, higher recoveries of the pesticide residues in the tobacco smoke from the amount spiked can be obtained. It was also found that cigarette filters help to reduce the intake of residues of pesticides that may be present in cigarettes. Finally, the study concluded that both active smoking and passive smoking populations are exposed to pesticide residues in the tobacco smoke.

Glyphosate in yam from Ghana.

Glyphosate is used in Ghana on many crops including yam. There is the suspicion that there could be residue problems in the yam crop. Glyphosate as a polar compound is noted for its difficulty to be analysed in biological matrices. In this study, the method for glyphosate analysis based on FMOC-Cl derivatization was modified with a clean-up (CH2Cl2) step and validated to analyse glyphosate in yam by LC-MS/MS. The results showed that the validated method was efficient for the analysis of glyphosate in yam, with recoveries of 34%, linearity of 0.997, RSD of 7%, LOD of 0.04 mg kg-1, and LOQ of 0.12 mg kg-1. Out of 68 samples analysed from a field experiment and from markets, glyphosate was detected in 14 samples, but at levels below the LOQ. It is concluded that the yam contained glyphosate residues at very low levels which may not pose threat to human health.

Pesticides use and exposure among yam farmers in the Nanumba traditional area of Ghana.

Over the years, pesticides have become a dominant feature of Ghana's agriculture. In the past, pesticides usage was restricted to the cocoa, cotton, vegetables, and fruits sectors. Today, there is a widespread use of pesticides in the cultivation of yam. Since the introduction of pesticides into yam production, farmers have expressed satisfaction about the relief it has brought them with regard to labor and productivity. However, there has been public concern about the human and environmental health impacts of pesticides. In this study, 100 farmers were interviewed through a structured questionnaire to determine their knowledge, awareness, and use practices of pesticides and to determine their level of exposure. The study revealed that the common pesticides currently being used for yam production are herbicides. Although the farmers are aware of the risks associated with the use of pesticides, they use more than the recommended doses and do not pay attention to the use of personal protective equipment (PPE) thereby predisposing themselves to the potential health effects of pesticides. A significant percentage (20 to 40%) of the farmers reported to have never used these PPEs and over 44% of them use glyphosate above the recommended dose (between 1.5 and 2 L/ha). This resulted in an average farmer exposure to glyphosate of 4.2 mg/kgBW/day, well above the acute reference dose (ARfD) of 0.5 mg/kgBW/day. The government should develop and implement programs to train pesticides dealers, educate farmers, enforce the laws on pesticides, and support farmers to uphold protective measures.

Evaluation of 99 Pesticide Residues in Major Agricultural Products from the Western Highlands Zone of Cameroon Using QuEChERS Method Extraction and LC-MS/MS and GC-ECD Analyses.

There is no information available on pesticide residue levels in major food commodities harvested in Cameroon, especially from the western highlands region, the food basket of the country. Hence, this study evaluated the residues of 99 pesticides in 72 samples of 12 agricultural products collected in the region, using QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) method extraction, and analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS) and gas chromatography with electron capture detection (GC-ECD). This method was suitable for detecting the targeted compounds: For 81 pesticides by LC-MS/MS, the limit of quantification (LOQ) was between 0.0004 and 0.0537 mg/kg; and for 18 halogenated pesticides by GC-ECD, it ranged from 0.0012 to 0.2180 mg/kg. The residues of 62 pesticides, including 12 banned compounds, were found in the samples. Insecticides (39.7%) were the most prevalent group, with all the samples containing at least one pesticide. Twenty-one pesticides (34.4%) exceeded their European Union maximum residue limits (MRLs) and 22 pesticides (34.4%) were found in all 6 sampling locations. Malathion and p,p'-DDT were the most distributed pesticides, found in almost all the samples and sampling sites. Food items with the highest rates of positive results were chili pepper (23.2%), white pepper (20.2%), kidney beans (17.3%), and soybeans (17.2%). Samples with residues above their MRLs represented 38% of all the positive analyses; chili pepper (6.4%) and kidney beans (5.5%) were found to have the most residues above their MRLs. The most critical food commodities were kidney beans, soybeans, chili pepper, and maize. This data presents scientific evidence that investigation into continuous monitoring and good regulation of pesticide usage in Cameroon is needed, and paves the way for health risks analysis.