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

Abstract

(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 β-hexachlorocyclohexane (β-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 β-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 β-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.

Keywords: Cameroon; POPs; food safety; organochlorine; pesticide residues; risk assessment.

Figure 1

Examples of gas chromatography-electron capture detector (GC-ECD) chormatograms for the standards at 0.01 mg/L (A) and a kidney bean sample (B).

Figure 2

Frequency of positive analyses of regulated halogenated pesticides residues in 11 food items from 3 cities of Cameroon, with indication of number of samples below and above the European Union maximum residue limits (MRLs). HCB = hexachlorobenzene, HCH = hexachlorocyclohexane, DDT = dichlorodiphenyltrichloroethane. ƩDDT = p,p’-DDT + op’-DDT + pp’-DDD + pp’-DDE. Ʃdieldrin = aldrin + dieldrin. Ʃendosulfan= α-endosulfan + β-endosulfan.

Figure 3

Representation of quantified halogenated pesticide residues among 11 food items from the 3 largest cities of Cameroon.

Figure 4

Average concentrations of halogenated pesticide residues in 11 food items from the 3 largest cities of Cameroon. HCB = hexachlorobenzene, HCH = hexachlorocyclohexane, DEE = dichlorodiphenyldichloroethylene, DDD = dichlorodiphenyldichloroethane, DDT = dichlorodiphenyltrichloroethane. ƩDDT = p,p’-DDT + op’-DDT + pp’-DDD + pp’-DDE. Ʃdieldrin = aldrin + dieldrin. Ʃendosulfan= α-endosulfan + β-endosulfan.

Figure 5

Relative contribution of halogenated pesticide compounds to the cumulative chronic health risk of food items from the 3 largest cities of Cameroon. ƩDDT = p,p’-DDT + op’-DDT + pp’-DDD + pp’-DDE. Ʃdieldrin = aldrin + dieldrin.