| 酸性矿山废水污灌区水稻土重金属的形态分布及生物有效性 |
| 摘要点击 3343 全文点击 1561 投稿时间：2008-06-12 修订日期：2008-07-11 |
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| 中文关键词 酸性矿山废水 水稻土 重金属 形态分布 生物有效性 |
| 英文关键词 acid mine drainage paddy soil heavy metals speciation bioavailability |
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| 中文摘要 |
| 通过野外采样调查和实验分析，对粤北大宝山矿山下游酸性矿山废水污灌区水稻土中重金属（Cd、Zn、Pb、Cu）的形态分布特征和生物有效性进行了研究.运用TCLP（toxicity characteristic leaching procedure）和BCR（community bureau of reference）连续提取法研究了土壤中重金属的生物有效性问题，并运用多元逐步线性回归分析进行对比.结果表明，酸性矿山废水污灌区水稻土中Cd以酸提取态和残渣态为主；Cu各形态含量的分配顺序为：残渣态>可还原态>酸提取态>可氧化态，以残渣态为主；Pb以可还原态和残渣态为主，占总量的86.54%；Zn主要以残渣态的形式存在、占总量的50%以上，各形态含量的分配顺序为：残渣态>酸提取态>可还原态>可氧化态.TCLP提取的重金属Cd、Cu、Pb和Zn含量分别为：0.17～0.89、 8.12～70.33、 3.16～90.33和10.24～106.85 mg·kg-1，其平均值分别为0.41、 36.60、 15.97和50.78 mg·kg-1.水稻籽粒中重金属Cd、Cu、Pb、Zn含量范围分别为：0.183～0.947、 3.542～5.997、 0.285～1.532和17.54～41.10 mg·kg-1.参照卫生部颁布的食品中重金属元素限量卫生标准评价水稻籽粒重金属污染情况，其结果表明，Cu和Zn含量未出现超标现象，而Cd和Pb含量超标现象很严重，其超标率分别为87.50%和81.25%.逐步回归分析结果表明，水稻籽粒中的Cd和Zn含量显著地受到土壤中酸提取态Cd和Zn含量的影响，Cu含量显著地受到酸提取态和可氧化态Cu含量的影响，Pb含量显著地受到可还原态Pb和有机质含量的影响.水稻籽粒中重金属含量受到TCLP提取重金属含量的显著影响，重金属总量、pH和有机质对其的影响不显著.TCLP法适于对酸性矿山废水污灌区水稻土重金属生物有效性进行快速简单地评估. |
| 英文摘要 |
| Based on field investigation and laboratory analysis，the speciation and bioavailability of the heavy metals (Cd，Cu，Pb，and Zn) was studied.These metals were tested from 16 soil samples taken from paddy soils irrigated by acid mine drainage in the lower stream of Dabaoshan mine area，Guangdong Province，China.The toxicity characteristic leaching procedure(TCLP) and three-step community bureau of reference(BCR) sequential extraction procedure methods were used to analyse the bioavailability of heavy metals.TCLP is currently recognized as an international method for evaluation of heavy metal pollution in soils.Two methods were compared in bioavailability by stepwise multiple linear regression analysis.Cd was dominated mainly by the acid-extractable and residual fractions，and followed by the order of acid-extractable > residual > oxidisable > reducible.Cu was dominated mainly by the residual fraction，and decreased in the following order：residual > reducible >acid-extractable > oxidisable.Pb was dominantly released in the reducible and residual fractions，they account for 86.54% of the total contents，and decreased in the following order：reducible > residual > acid-extractable > oxidisable.Zn was dominated mainly by the residual fraction，it takes more than 50% of the total contents，and followed by the order of residual > acid-extractable >reducible >oxidisable.The levels of Cd，Cu，Pb and Zn extracted by TCLP were 0.17-0.89， 8.12-70.33， 3.16-90.33 and 10.24-106.85 mg·kg-1，respectively，and the average concentrations of Cd，Cu，Pb and Zn were 0.41， 36.60， 15.97 and 50.78 mg·kg-1，respectively.The concentrations of Cd，Cu，Pb and Zn in rice seeds were 0.183-0.947， 3.542-5.997， 0.285-1.532 and 17.54-41.10 mg·kg-1，respectively.Comparing to the national standards on heavy metals in foods by the Chinese Ministry of Health，the contents of Cu and Zn in rice seeds didnt exceed the upper limit，while the contents of Cd and Pb in rice seeds exceed the upper limit by 87.50% and 81.25%，respectively.Results of the stepwise multiple linear regression analysis revealed that contents of Cd and Zn in seeds of rice were significantly influenced by contents of acid-extractable Cd and Zn，that contents of Cu in seeds of rice were significantly influenced by contents of acid-extractable and oxidisable Cu，and the contents of Pb in seeds of rice were significantly influenced by contents of reducible Pb and organic matter.Contents of four metals in seeds of rice were significantly influenced by contents of metals extracted by TCLP，and the influences of total content，pH and organic matter were not significant.In short，TCLP method was fast，simple and suitable for evaluation of bioavailability of heavy metals in sewage-irrigated paddy soils by acid mine drainage. |
