1026 EVALUATION OF HEAVY METALS AND PESTICIDES CONTENTS IN MARKET-GARDENING PRODUCTS SOLD IN SOME PRINCIPAL MARKETS OF OUAGADOUGOU (BURKINA FASO) Tarnagda Bakary 1 , Guira Flibert 1 , Sourabié Pane Bernadette 2 , Zongo Oumarou 1 , Tapsoba François 1 , Zongo Cheikna 1 , Drabo Koine Maxime 2 , Traoré Yves 1 , Savadogo Aly 1 * Address(es): Prof. SAVADOGO Aly, 1 Laboratory of Applied Biochemistry and Immunology (LaBIA), Research Center in Biological, Food and Nutritional Sciences, University Ouaga I Pr Joseph Ki- Zerbo, 03 BP7021, Ouagadougou, Burkina Faso. 2 National Laboratory of Public health, Department of Pesticides, Contaminants and Manure, Tel/Fax (226) 25 37 31 31, 09 BP 24 Ouagadougou 09, Burkina Faso. *Corresponding author: alysavadogo@gmail.com ABSTRACT Keywords: Heavy metals; Vegetables; Pesticides; Markets; Polluant , Ouagadougou INTRODUCTION Truck farming is being developed in cities in developing countries to ensure food security. It is also an income generating activity for households. In Africa, truck farming is currently part of hidden hunger solution among large cities' neighbourhoods population (Touré et al., 2015; Yao et al., 2016). Insects attacks and plants pathologies are most of the obstacles to truck farming. Market- gardeners use available chemical pesticides to limit the damage to their crops. Unfortunately pesticides are used in anarchistic and abusive ways (Son et al., 2017; Tarnagda et al., 2017). The risk of this practice is also increased by the ignorance of the market-gardeners (Diop, 2013). Urban origin market-garden products are nutritionally rich but are not always safe. The production sites of market-garden products around urban cities are subject to contamination by residues of medicine (Koffi-Nevry et al., 2012; Touré et al., 2015). Majority of the sites of production of market-garden products are located in places polluted with domestic and industrial wastes. Some sites of gardening in the urban cities are located in or close to household refuse dump sites or industrial waste disposal sites where there is frequent incinerations of wastes (Ahouangninou et al., 2011; Kanda et al., 2013). Pesticides are frequently used to increase vegetables production (Yao et al., 2016; Son et al., 2017; Tarnagda et al., 2017). Pesticides and heavy metals have chronic effects on human health. Among the critical points for hazard analysis of market-garden products, the site of production and the utilization of pesticides are very important. Without an adequate mechanism of control, the use of pesticides present a medical and an environmental risk (Yao et al., 2016; Tarnagda et al., 2017). The effects on the environment in general, the ground and the cultivated plants in particular, are considerable, because these husbandries are likely to involve an accumulation of heavy metals and pesticides in the plants and the surface layers of the ground, rich in organic matter (Touré et al., 2015). The "babenda" is a Burkinabe dish made mainly of leafy vegetables (Hibiscus sabdariffa, Amaranthus hybridus, and Cleome gynandra) coarsely chopped and millet or rice that was boiled together.Vegetables play an important role in diversifying the diets of people in developing countries and are a major source of nutrients. Indeed, because of their richness in protein, fiber, minerals, vitamins, and antioxidants, vegetables help to improve the health of populations (Lock et al., 2005). They are therefore of nutritional interest in the fight against micronutrient deficiencies (Devadas et al., 1980). The iron content of amaranth (Amaranthus cruentus) and cornet (Corchorus olitorius) is 22 to 77 mg / 100 g dry matter (Ndlovu et al., 2008). The β-carotene content of black nightshade (Solanum scabrum) is 3943.03 ± 0.89 μg / 100 g in relation to the crude product (Soro et al., 2012).It is a sauce that is prepared in the villages during the lean season, when there was not enough millet or other grains to provide for the families until the harvest. In fact, at the base of this leaf sauce was mainly bean leaves and sorrel crushed and millet that were boiled together.This study was aimed at evaluating the contents of heavy metals and pesticides of market- gardening products (Amaranthus hybridus, Hibiscus sabdariffa, Cleome gynandra and Ipomaea batatas) and babenda sold in twenty principal markets of Ouagadougou. MATERIAL AND METHODS Sampling and preparation of the vegetables A total of 120 samples of four vegetables and 40 babenda samples commonly consumed by the local population were collected. The concerned vegetables were: Amaranthus hybridus: Borom-bouli, Hibiscus sabdariffa: Bito, Cleome gynandra: Kenebdo, and pomaea batata: Nagnui-noodo Samples were taken randomly from 20 principal markets ( Zone1 yaar, Wemtenga yaar, : Zogona Pesticides and heavy metals are persistent organic pollutants responsible for immune deficiency, certain types of cancer, and decreased length of pregnancy.In this study, 20 chemical pesticides and 4 heavy metals were detected from 120 samples of 4 types of vegetables and 40 samples of babenda collected from Ouagadougou principal markets. The "babenda" is a Burkinabe dish made mainly of leafy vegetables (Hibiscus sabdariffa, Amaranthus hybridus, and Cleome gynandra) coarsely chopped and millet or rice that was boiled together.A multi-residue method was developed to detect the pesticides in the samples collected by gas chromatography, with micro electron capture detector. The concentration of cadmium, lead, mercury and arsenic were obtained from the 120 vegetables samples by using an atomic absorption spectrometer. Residues of pesticides were detected in 87% of the samples, and among the positive samples, 58.40% contained concentrations higher than the limit of maximum residue (LMR). Thirteen active pesticide residues were detected in the vegetables. The contents of the majority of pesticides residues were higher than the LMR. Seven active ingredients were detected in the babenda. 50% of the samples had more than one pesticide residue. The heavy metal concentrations ranged from 0.0098 to 2.66 mg.kg -1 for Hg; 0.01 to 1.146 mg.kg -1 for Pb; 0.016 to 1.72 mg.kg -1 for Cd and 0.012 to 1.885 mg.kg -1 for As. The relative abundance of heavy metals in the vegetables followed the sequence Cd (0.018 mg.kg -1 ) > Pb (0.016 mg.kg -1 ) > As (0.012 mg.kg -1 ) > Hg (0.0098 mg.kg -1 ). In addition, the concentration of heavy metals in the samples collected from the different markets exceeded the threshold according to the lawful maximum concentration (CMR) established in France. The continuous follow-up and a strict regulation of these pollutants in the vegetables particularly, are necessary. ARTICLE INFO Received 27. 5. 2018 Revised 4. 11. 2018 Accepted 7. 11. 2018 Published 1. 2. 2019 Regular article doi: 10.15414/jmbfs.2019.8.4.1026-1034