Accumulation of Heavy Metals in Vegetable SpeciesPlanted in Contaminated Soils in Farmlands Irrigated by Karoon River in Ahvaz the Health Risk Assessment

Heavy metal elements, such as lead (Pb), cadmium (Cd), Chromium (Cr), etc., have toxic effects on human health. Toxic metals can accumulate persistently in the body over a lifetime.Heavy metals are very important from nvironmental aspects due to their toxicity and accumulative properties. Due to the low mobility, these elements gradually accumulate in soil and eventually enter the food chain and threaten human and other organism’s health. Therefore, measurement and monitoring of heavy metal concentrations is necessary to .. The aim of this study was to evaluate the concentration of lead, cadmium and chromium in irrigation water, soil and vegetables in farmlands lands in Ahwaz (southwest of Iran)The studied vegetables were basil, radish and purslane. The sampling was performed during June to August in 2015 on water, soil and vegetable in Ahwaz farmlands. Seventy samples of vegetables were collected and analyzed by furnace atomic absorption spectrop otometry according to standard methods. Also, samples of water and soil were analyzed according to standard methods. The concentration of lead, cadmium and chromium in vegetables, soil and irrigation water were compared with the standard values recommended by WHO and FAO.Results showed that lead, cadmium and chromium contents in vegetables were in the range of 9.7- 11.13, 1.97- 3.20, and 0.12- 0.17 mg/kg, respectively. Statistical analysis showed a significant difference between mean concentration of lead and cadmium in vegetables and the permitted value (P<0.05). By comparing the result with the permissible limit which is reported by WHO/FAO, lead and cadmium contents of the vegetables are above the recommended value. Theme an concentration of lead in basil, radish and purslane were 9.7, 10.61, and11.13 mg/kg, respectively. Mean concentration of lead in water and soil were 0.47 and 10.19 mg/kg, respectively.The lead contents in vegetables were higher than standard values recommended by WHO/FAO. High concentration of lead in vegetables could be due to high accumulation of this metal in soil. Therefore, continues monitoring of heavy metals in soil and irrigation water of farmlands plays an important role in reducing the environmental risks threating human health.

Keywords:

Heavy metals , vegetables , irrigation water , agricultural soil , health risk , Karoon river