Assessment of Heavy Metals and Microbial Pollution of Lettuce (<i>Lactuca sativa</i>) Cultivated in Two Sites (Paspanga and Tanghin) of Ouagadougou, Burkina Faso

Abstract

Environmental pollution can have detrimental effects on crop yield and its consumers. The current study was designed to investigate the potential human health risks associated with the consumption of lettuce crop contaminated with toxic heavy metals and microbiological status. Irrigated water, soil and lettuce were analyzed by AAS technics for heavy metals including Cd, Cr, Cu, Mn, Ni, Pb and Zn. Transfer factor (TF), daily intake of metals (DIM) and health risk index (HRI) were also calculated. Microbial analysis was carried out for the presence foodborne pathogens. The results showed that the heavy metals contents were higher in the soil than wastewater and the vegetables. Heavy metals ranged (mg•Kg −1) for Cd (1.27 to 2.93), Cr (7.28 to 7.38), Cu (0.91 to 1.70), Mn (0.29 to 6.60), Ni (1.74 to 2.16), Pb (1.32 to 1.69), Zn (3.08 to 3.79); and were higher than the WHO maximum limit permissible (ML) in vegetables. HRI < 1 indicates minimal risk. TF values designated an enhanced bio-contamination. Microbial numeration revealed the presence of spoiler and pathogenic microorganisms. The lettuce tested was not safe for human use, especially for direct consumption by human beings.

Health Risk Assessment of Heavy Metals and Microbial Quality of Local Tomato (&lt;i&gt;Solanum lycopersicum&lt;/i&gt;) of Ouagadougou, Burkina Faso

“…In contrast, Somda et al [9] have reported a lower level of heavy metals in the wastewater from other sites as Paspanga and Tanghin. All the samples collected from the two sites were above the maximum limits in the wastewater samples set by FAO and reported by Somda et al [9]. These findings demonstrated that high level of metals may be due to industrial activity around the sites and agricultural practices.…”

“…The metal concentrations showed variation which can be attributed to the differences in physiology of the different samples for uptake, exclusion, bioaccumulation and retention of heavy metals [39]. The results from earlier reports of Somda et al [9] demonstrated that plants grown on wastewater-irrigated soils are contaminated with heavy metals and pose a health concern. According to other authors the use of wastewater from the city in agriculture irrigation may have significant effects of accumulation of toxic heavy metals in soils and agricultural practices.…”

“…Soil samples were taken from 0 -30 cm depth in two sites (Boulmiougou and Kossodo) and prepared for physical and chemical analysis and heavy metal content using method of Somda et al [9]. were taken by hands protected with vinyl gloves and carefully packed in polyethylene bags [14].…”

“…Fruit-sets of tomato were hand harvested, and low groundwater (wastewater) was collected from two sites (Boulmiougou and Kossodo) of production. The samples were processed according to the method of Somda et al [9].…”

“…This could be due to industrial wastewater, sewage sludge applications, fertilizers, and watering practices in agricultural lands. The use of wastewater from the city in agriculture irrigation may have significant effects of accumulation of toxic heavy metals and microorganisms in soils and agricultural products [6] [7] [8] [9].…”