Reduction of heavy metals content in contaminated vegetables due to the post-harvest treatments

Abstract

HEAVY metals highly contaminated samples of potato, tomato, and cucumber were used to study the effects of washing, shelling and soaking (in vinegar 5% for 5 min.) on heavy metals reduction. Heavy metal levels were determined for untreated and treated samples using Atomic Absorption Spectrophotometer and the reduction ratios of heavy metal levels were calculated. The vinegar (acetic acid) effect could be due to its effect on the pH value that influences the solution chemistry of the heavy metals such as hydrolysis, complexation by organic and inorganic ligands, redox reactions, precipitation and the adsorption availability of the heavy metals. For potato, the results revealed that washing and shelling have removed high ratio of heavy metals, however the reduction was not sufficient to decrease the levels of Pb and Cd to be within the MRLs. While soaking in vinegar in addition to washing and shelling of potato has led to a significant decrease in Pb and Cd concentrations being lower than the MRLs. For tomato and cucumber, the Cd element was not detected after washing of both vegetable kinds. Lead level in tomato was significantly decreased to the MRLs values when washed and shelled, while Pb level in cucumber was still higher than MRLs.