Estimation of the Degree of Heavy Metal Pollution in Market Gardening Soils in Kadiogo Region, Burkina Faso

Abstract

The objective of this study is to estimate the degree of heavy metal pollution (As, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, Tl and Zn) of market gardening soils in the Kadiogo region. This work provides reassurance about the quality of the studies soils in the central region of Burkina Faso. Thirty-two (32) market garden soil samples, including two (02) for the background, were measured using ICP-MS. Indeed, the results show that the average concentrations of heavy metals in the 0-20 cm soil profile respect the recommended limits. However, Contamination Factors (CF) and Pollution Load Index (PLI) show that certain soils are polluted. These indices reveal that the pollution of exploited soils differs not only from one site to another but also between the 0-10 cm and 10-20 cm levels. Thus, the most polluted soil on the surface (0-10 cm) is SK2 in Koubri with a PLI of 8.20 compared to 0.24 for STD1 in Tanghin-Dassouri. For the 10-20 cm horizon, the PLI values show that the soils PO5 (Pissy), PO1 (CHU-YO), PO2 (CHU-YO) and PK3 (Koubri) already polluted at the surface (0-10 cm) the rest in profile (10-20 cm). Also, we can emphasize that the presence of non-essential trace metal elements such as Pb, As and Hg constitute a threat to the health of consumers of market garden products from these sites. In addition, the low concentrations of metals in the soil samples suggest that this is diffuse pollution.