Investigation Of Selected Heavy Metals In Tomato (Solanum Lycopersicum) Vegetable Produced Usingirrigation Water Of Awash River In East Shoa Zone,Oromia Regional State,Ethiopia

Abstract

Vegetables are important components of human diet. As a result of environmental pollution the food safety of vegetables including tomato has become one of the concern of researchers. Globally, heavy metal contamination of vegetables is one of the most important aspects of food quality assurance.The study evaluates concentration levels of some heavy metals in tomato (Solanumspp.) vegetable sample by Atomic Absorption Spectroscopy cultivated in East Shoa Zone, Oromia Region, Ethiopia by the digestion procedures of 0.5 g of homogenized and powdered tomato sample was placed in microwave digestion vessel to which 9 ml of 10M HNO3 and 3 ml 10 M HCl were added. The vessels were tightly capped and placed in the microwave digestion system and digestion take place at 180˚C for 45 min`s until a clear solution were obtained. In this study, tomato samples from three villages (kebeles), namely Kona Dagaga, Bato, and Ulaga villages of Adama area were collected and analyzed for cadmium (Cd), lead (Pb), chromium (Cr), cobalt (Co), nickel (Ni), copper (Cu), iron (Fe),manganese (Mn) and zinc (Zn). The results revealed that the mean heavy metal concentrations in tomato sample for Cd, Pb, Cr, Co, Ni, Cu, Mn, and Zn were in the range of 3.2–3.46, 2.02-12.7, ND - 5.8, ND- 29.6, 28.89-34.4, 7.11-23.55, 20.6-26.73, 6.91-18.9 and 25.42-35.3 mg/kg, respectively. In general, the level of metals in tomato collected from the sampling sites are found to be in the decreasing order of Zn>Ni> Co>Fe>Cu>Mn>Pb>Cr>Cd. When compared to the WHO/FAO thresholds values for the metals, the concentration levels of Pb, Cd, Cr and Ni were exceeded (Dagaga > Ulaga > Bato) the threshold values for tomato vegetable for human consumption. This indicated that these metals (i.e., Pb, Cd, Cr and Ni) can cause unintended health effects to the consumers. The health index (HI) owing to tomato in Dagaga, Bato and Ulaga ingesting were 48.9%, 21.7% and 29,4% respectively, signifying likely adversative health implication to the population from the ingestion of the tomatoes. The Total Cancer Risk (TCR) analyses have uncovered the possible cancer hazard persuaded by Cd, Cr, and Ni from the ingestion of all area tomatoes. From the outcomes this study, it can be concluded that the water and vegetables from Dagaga areas are possibly contaminated with toxic metals and hence demand strict monitoring to safeguard the public around the study area and beyond