花生和油菜对重金属的积累及其成品油的安全性

土壤重金属污染日益严重,植物修复作为一种环境友好型的技术越来越受到关注。选取种植在郴州重金属污染土壤地区的花生和油菜2种油料作物,研究了重金属在这2种油料作物各部位的分布情况,再利用2种有机溶剂(正己烷和石油醚)对果实进行索氏萃取,探讨油中重金属的残留情况。结果表明,花生和油菜对重金属有一定的耐性和积累能力,花生根、茎、叶对重金属Pb、Cu、Cd积累性较强,其中Cd在根、茎、叶中的富集系数都高于4,为土壤本底值的5~6倍。花生红皮则对Cu表现出较强的富集能力,富集系数为3.30,浓度达到了358.26 mg/kg;油菜中重金属Zn、Cu、Cd在各部位的分布为:叶>根>果荚>茎>籽,说明油菜叶对Zn、Cu、Cd的积累能力更强。通过2种有机溶剂对花生果实和油菜籽进行萃取,结果发现,石油醚对花生油的萃取率高于正己烷,正己烷对油菜的萃取率大于石油醚,且花生和菜籽的毛油中重金属As和Pb的含量都符合国家《食用油卫生标准》GB2716-2005(≤0.1 mg/kg)。

Accumulation of heavy metals by peanut and rapeseed and safety of their refined oil

Phytoremediation, as an environmentally-friendly technology, has been more concerned due to the serious soil heavy metal pollution. The research focused on the heavy metals' content distribution in different parts of peanut and rapeseed, by choosing the above two crops which were planted in seriously polluted soils by heavy metals in Chenzhou, and analyzed the heavy metal residues in oil extracts by using two kinds of organic solvents (petroleum and N-hexane) to do soxhlet extraction to their fruits. The result showed that peanut and rapeseed both have tolerance to some heavy metals and remediation to soils to some extent. Detailedly speaking, peanut roots, stems and leaves showed a strong accumulation ability of Pb,Cu,Cd, in which the enrichment coefficient index of Cd in roots, stems and leaves was more than 4, 5~6 times higher than the soil heavy metals background values. Peanut redskins had a strong enrichment capacity of Cu, reaching 358.26 mg/kg, with the enrichment coefficient index being 3.30.The distribution situation of Zn, Cu and Cd in rapeseed was leaves > roots > rapeseed fruit pods > stems > rapeseed, which meant that rapeseed's leaves had a much stronger accumulation ability of Zn, Cu and Cd than its other parts. The result of fruits Soxhlet extraction by using two kinds of organic solvents showed that the petroleum extract rate of peanuts was higher than N-hexane, on the contrary the N-hexane extract rate of rapeseeds was higher than petroleum. Meanwhile, neither of the contents of As and Pb in the oil of peanuts and rapeseeds was higher than 0.1 mg/kg with the two different organic solvents, which were accord with the national edible health standards GB2716-2005.