芜湖钢铁厂周边土壤及油菜籽中镉、铜、锌、铅含量和形态分布研究

研究了污染土壤、油菜籽中Cd、Cu、Zn、Pb含量、形态分布特征和重金属富集状况及可能存在的生物毒性.结果表明,土壤中Cd、Zn、Pb以铁锰氧化物结合态、Cu以残留态占5种形态最高比例,分别为31.1%、39.3%、53.79%、46.24%;Cd、Pb交换态比例较高,为23.47%、16.32%,Cu、Zn的交换态比例较小,为3.14%、0.54%;土壤中不同重金属与各重金属形态相关关系有差别,5种重金属形态转化为有效态重金属难易程度不同;油菜籽和油菜籽壳中不同重金属累积趋势有差异,Cu易在油菜籽壳中累积,Cd、Zn、Pb易在油菜籽中累积;油菜籽中不同重金属累积率不同,Cd累积率最高,为0.56.油菜籽中重金属累积率与土壤中重金属总量呈显著负相关关系(P＜0.05),土壤中重金属的形态、转化差异是此种负相关关系的主要原因;油菜籽中Cd、Cu、Pb以氯化钠态为主,分别为32.50%、22.94%、34.69%,Zn以EDTA态为主,为45.97%.油菜籽中重金属形态可能影响其毒性,但其毒性的人类膳食风险还需进一步研究证实.油菜籽中重金属形态与油菜中重金属总量相关性不好.

Cd,Cu,Zn and Pb contents and forms in soils and rapeseeds around Wuhu Plant

The study showed that around Wuhu Plant,soil Cd,Zn and Pb mainly existed in Fe-Mn oxide form,and Cu in residual form,with the percentage of 31.81%,39.83%,53.79%,and 46.24%,respectively.Soil exchangeable Cd and Pb had a higher proportion (23.47% and 16.32%) than soil exchangeable Cu and Zn (3.14% and 0.54%).The correlations between soil heavy metals and their forms,as well as their transformation to available form were different.Different heavy metals had different accumulation trends in rapeseed and its hull.Cu easily accumulated in hull,while Cd,Zn and Pb had a higher accumulation in seed.The accumulation rate of heavy metals in rapeseed and hull was also different,being the highest for Cd.There was a significantly negative correlation (P<0.05) between the accumulation rate of heavy metals and their contents in soil.In rapeseed,Cd,Cu and Pb were mainly in sodium hydroxide form,with the percentage of 32.50%,22.94% and 34.69%,respectively,while Zn was mainly in EDTA form,with a percentage of 45.97.The existed forms of heavy metals in rapeseed probably affected their toxicity,but the toxicity to human food could not be inferred from this research,and needed to be studied further.There was a weak relation between heavy metals contents and their existed forms in rapeseed.