BACTERIAL QUALITY AND CYTOTOXICITY SCREENING OF FRESH VEGETABLES IRRIGATED WITH POLLUTED WATERS

Abstract

The mutagenic effects of raw vegetables irrigated with polluted water and their bacterial quality were studied. Two vegetables, lettuce (Lactuca sativa) and fluted pumpkin (Telfaria occidentalis) were planted in sterile soil and irrigated with sewage-polluted stream, rain, tap and well waters, and harvested. The presence of pathogenic bacteria on the vegetable leaf surfaces was determined. The Allium cepa assay was then used to evaluate the genetic and acute effects of the vegetable leaf extracts. The heavy metal concentrations of the vegetables were determined using atomic absorption spectrophotometry. Pathogenic bacteria isolated were Escherichia coli, Staphylococcus aureus, Salmonella paratyphii, Shigella dysenteriae, Klebsiella pneumoniae, Aeromonas hydrophila and Enterobacter aerogenes. In A. cepa assay, none of the treatments induced chromosome aberration at the tested concentrations, but retardation of growth and suppression of mitotic activity occurred. The concentrations of heavy metals in the vegetables were lead (0.261-0.531mg/kg), zinc (0.142-1.618mg/kg), cadmium (0.00-0.13mg/kg), copper (0.021-0.057mg/kg), iron (0.711-1.122mg/kg) and chromium (0.00-0.14mg/kg). This study shows that irrigation waters could have effects on the quality of edible vegetables.