Evaluation Of Pesticide Residues On Beta Vulgaris Subsp. Vulgaris, Solanum Tuberosum And Brassica Oleracea Var. Capitata In Bloemfontein

Abstract

The presence of pesticide residues in vegetables and related fresh products agricultural products is a health concern to consumers. Thus, this study aimed to evaluate the level of pesticide residues in the staple vegetables; cabbage (Brassica oleracea L.), Swiss chard (Beta vulgaris spp.) and potato (Solanum tuberosum L.) from fresh produce markets in Bloemfontein area. A total of 15 vegetable (three per five sites) samples were analyzed for the presence of 16 selected, commonly detected pesticides using the quick easy cheap effective rugged and safe (QuEChERS) extraction method and further quantified using gas chromatography coupled to high-resolution time-of flight mass spectrometry (GC-HR-TOF-MS). Results from GC-HR-TOF-MS were used to estimate human health risk exposure and uncover the limitation of the Fertilizers, Farm Feeds, Seeds and Remedies Act No.36 of 1947 (Fertilizers Act) safety on the use of pesticides on vegetables to human. The results revealed that all of the residues detected were below the maximum limits set by the Codex Alimentarius Commission (CAC). Vegetable samples analyzed had detected pesticide residues in 73.4% of the samples, while 26.60% had no compounds. The highest concentration of chlordane at 1.62 x 10-2 ng∙g-1 and heptachlor at 1.22 x 10-2 ng∙g-1 was detected from cabbage; followed by Swiss chard with endosulfan ether at the concentration of 1.33 x 10-2; and lastly potato with methoxychlor at the concentration of 1.05 x 10-2 ng∙g-1. The highest estimated daily intakes (EDIs) for an average person was 10 % for aldrin of the acceptable daily intake (ADI). The most critical commodity was cabbage, contributing 1.27% to acute consumer health risk (aHI) for chlordane. Regardless of low levels of pesticide residues in vegetables. Results in this study could indicate Good Agricultural Practices (GAPs) by farmers. However, there are still presence of long time banned pesticides residues such as hexachlorobenzene, lindane, heptachlor, heptachlor epoxide, chlordane, chlorbicyclen, dieldrin, endrin, methoxychlor, endosulfan ether, p,p’-DDE, o,p’-DDD, o,p’-DDT and aldrin. Thus, there are limitation and discrepancies in the Fertilizers Act, particularly on effective pesticide residues management in the country. Moreover, this shows the gap on the RSA pesticide monitoring program, procedure of pesticides registration and personnel training. To date, RSA only enforce monitoring adherence on exportation than the importation due to lack of expertise and expensive procedures mentioned. Furthermore, the regulations of the Fertilizers Act do not encourage co-ordination among departments that focuses on pesticides controls. These challenges impact the effectiveness of pesticides management and safety of agricultural products.