Heavy Metal Accumulation in Vegetables and Assessment of their Potential Health Risk

Abstract

Vegetables constitute essential diet components by contributing carbohydrates, proteins, vitamins, iron, calcium and other nutrients that are in short supply. The present study was conducted to evaluate vegetables such as leafy (spinach), melon (gourd, long gourd and pumpkin) and solonaceous (brinjal) for their potential to accumulate different heavy metals like Cadmium (Cd), Manganese (Mn), Chromium (Cr), Copper (Cu), Iron (Fe), Nickel (Ni), Lead (Pb) and Zinc (Zn). The content of these metals was measured by using Atomic Absorption Spectrophotometer. Mean values were recorded against each vegetable for accumulating heavy metals. It was observed that maximum concentration of Mn (137.3 mg/kg), Cr (6.62 mg/kg) and Fe (968.25 mg/kg) was found in spinach, exceeding the allowed threshold 2.2 mg/kg, 2.3 mg/kg and 425 mg/kg respectively, as set by WHO/FAO. While melon showed great potential to absorb Ni (5.05 mg/kg) which elevated safe limit 0.1 mg/kg and Cu (65 mg/kg) was within the safe range. Brinjal displayed maximum absorption of Zn (41 mg/kg), which did not cross the WHO reference limit 73 mg/kg. In case of Cd both gourd and brinjal showed equal concentration of 0.39 mg/kg but was not at the safe limit 0.241 mg/kg. However levels of Pb were below the FAO/WHO recommended limits in all the vegetables. Low concentrations of Pb indicate that these plants contribute less toxic effects of metals. Overall this order of absorption was recorded as leafyA‹ÂƒmelonA‹Âƒsolonaceous. Human DIM has also been computed and was observed below recommended values by the FAO/WHO. However, to prevent any chronic health risk and extent of heavy metal contamination, steps must be taken to reduce human activities at the sites. Regular monitoring of heavy metals in the vegetables grown in wastewater irrigated areas is also necessary.