Heavy metals accumulation and distribution pattern in different vegetable crops

Abstract

Different vegetable crops grown on heavy metal contaminated soil showed marked difference in metal accumulation, their uptake and distribution pattern. Crop species also showed remarkable difference in metal concentration of various plant parts. Based on metal accumulation in edible parts and whole plants, root vegetables namely, radish and carrot registered lower accumulation of almost all heavy metals except Zn in radish root. However, leafy vegetables namely, spinach, amaranthus, mustard and fenugreek recorded higher accumulation of both essential and non-essential heavy metals, except Cd and Ni which showed less accumulation in fenugreek. Potato and onion showed lower accumulation of Zn and Cu and higher accumulation of Cd and Ni. Cauliflower and cabbage, however, showed greater accumulation of Pb and Ni, but less accumulation of Cu and Cd. Among fruit type vegetables, pea, soybean and cluster bean showed greater accumulation of Pb and Ni and very less accumulation of Cd. Among different vegetables cauliflower and cabbage recorded highest uptake of Zn, Pb and Ni, while mustard showed higher uptake of Zn and Cd. In general the uptake of Cd was lowest in almost all the crops except mustard. Generally the root and leafy vegetables namely. radish, carrot, spinach, amaranthus, mustard, cauliflower and cabbage showed higher distribution of metals to the edible parts, whereas fruit types vegetables specially tomato and brinjal exhibited least transport of metals to fruits except leguminous fruit vegetables pea and soybean. Leafy vegetables namely, spinach, amaranthus and mustard seemed to be unsafe and not suitable for cultivation on heavy metal contaminated soil. Most of the fruit type vegetables could be suggested for cultivation on Cd contained soil but not for Ni and Pb contained soil.

Assessment of heavy metals uptake in leafy vegetables grown on long term wastewater irrigated soil across Vrishabhavathi River, Bangalore, Karnataka.

“…The concentration of heavy metals present in the order of Fe>Zn>Mn>Cu>Ni>Pb>Cr. Singh [16] showed that irrespective of crop the average metal content was in the order of Zn>Cu>Pb>Ni>Cd. The transfer factor for amaranthus species is in the order of Zn>Mn>Fe>Cu>Ni>Pb>Cr as shown in figure 2.…”

Accumulation of some heavy metals in plants and soils adjacent to Cairo – Alexandria agricultural highway

“…Such suspended particles might precipitate at high concentrations in soils near highway and, to a lower extent, at lower concentrations away from the highway. There are several forms of heavy metals in soils, a soluble form which is available to be absorbed by plants as well as complexed forms consist of heavy metals combined with organic or in organic compounds (Singh et al, 2012 andRadulescu et al, 2013). Heavy metals translocation from soil solution through roots to other plant parts and accumulate in high concentrations causing a serious risk on human health when these plants are consumed (Ashworth and Alloway, 2004).…”

Heavy Metal Accumulation in Edible Part of Eleven Crops Cultivated in Metal Contaminated Soils and Their Bio-concentration Factor

“…미국EPA (Environmental Protection Agency)는 토양-작물-인체로 의 중금속 전이를 고려하여 토양 중 중금속 기준(SSLs, Screening Levels)을 설정할 필요가 있고, 이를 위해서 식용 작물의 생물농축계수(bioconcentration factor)를 적용할 것 을 추천하고 있다 (USEPA, 1996). 또한 국외연구 사례에서는 오염농경지에서 생산되는 농산물의 안전성확보를 위해 재배 가능한 작물의 우선순위를 제시하고 있기도 하다 (Singh et al, 2012). 반면 우리나라는 토양의 중금속 오염도 및 작물별 중금속 흡수율 차이를 고려하지 않고 관행작물을 지속적으로 재배하고 있다.…”