FRESH TOMATOES

This study was carried out to determine the concentrations of some heavy metals, such as nickel, cadmium, mercury, and oxidative stress status of tomatoes sold in local markets in Benin City, Edo State, Nigeria. Fresh tomato samples were brought from Uselu and Ikpoba Hill market in Benin City. The samples were oven-dried at 105°C for 24 hours and grinded to powder. The powdered samples were dissolved in deionized water, filtered through Whatman filter paper, and the volume was made up to 25 ml using 10 ml of 98% nitric acid. The resulting solution was analysed for the presence of heavy metals using an Atomic Absorption Spectrophotometer
(AAS, Perkin Elmer model 2130). The results showed that the nickel concentration present fresh tomato samples obtained from the two markets ranged from 0.13 mg/kg to 0.16 mg/kg, while
the cadmium concentration ranged from 0.11 mg/kg to 0.13 mg/kg. However, when compared to
W.H.O standard, the heavy metal concentration was slightly above the recommended value of
0.10 mg/kg. Also, oxidative stress analysis showed that the superoxide dismutase (SOD) value
ranged from 3.02 U/g to 3.48 U/g, Catalase (CAT) value ranged from 0.08 U/g to 0.10 U/g, the glutathione peroxidase (GPx) value ranged from 4.96 U/g to 5.73 U/g, while the malondialdehyde (MDA) value ranged from 0.50 U/g to 0.64 U/g respectively. These findings were indicative of environmental pollution due to industrial and vehicular emissions and also the mode of handing and processing of the samples. Although the heavy metals detected in this study are not beneficial to man and plant, low concentration can prove detrimental to health.