【作者】 贺静；

【导师】 林玉锁； 宗良纲；

【作者基本信息】 南京农业大学 ， 环境科学， 2009， 硕士

【摘要】 重金属元素铜、镉是土壤主要的重金属污染元素。铜是植物生长发育必需的营养元素,也是污染环境的重金属元素,镉是毒性仅次于汞的非生物必需元素,二者在土壤中的大量累积,降低了农产品的产量和质量,威胁着人畜的健康,它们对土壤——植物环境的污染受到了广泛的重视。但元素在土壤中的全量仅代表其在土壤中的资源禀赋,不能充分的说明其在土壤——植物系统中的生物活性,因此引进了重金属“有效态”的研究,并成为近年来土壤重金属污染研究的热点。本研究以江西某铜冶炼厂周边污染土壤及相应水稻作为研究对象,结合实验室黑麦草盆栽试验,研究0.1mol/L HCl (1#)、0.5mol/L HOAc(2#)、0.1mol/L NaNO3(3#)、0.01mol/L CaCl2 (4#)、1mol/L NH4OAc (5#)、1mol/L NaOAc (6#)六种常规化学提取剂与实际生物利用的相关性,并探讨不同提取条件对主要提取剂提取量的影响,主要得出以下结论：(1)土壤有效态Cu的提取量因提取剂不同差异相对较大,各提取剂按平均提取量排序为：1#>2#>4#>5#>3#>6#,土壤有效态Cd的提取量因提取剂不同差异相对较小,各提取剂按平均提取量排序为：1#>5#>4#>2#>6#>3#。土壤有效态Cu的提取结果变异系数相对较小,Cd的提取结果的变异系数相对较大,3#、4#提取剂的提取结果相对最稳定。(2) 1#、4#、5#、6#提取剂对土壤有效态Cu、Cd的提取量与黑麦草及水稻中Cu、Cd的含量都具有较好的相关性,但综合来看,4#、5#提取剂的提取效果最好,所提取的有效态Cd、Cu与土壤、水稻籽粒及黑麦草中的含Cu量、含Cd量均呈显著相关,且测定结果的变异系数在这几种提取剂中最小。(3)提取时间对两种提取剂提取土壤有效态Cu有较大影响,在2h内,提取量随提取时间延长呈指数型增长,2h后提取量不再发生较大变化；两种提取剂的提取率都随土液比减小而增大；提取率随提取剂浓度的增加而增加,不同处理间有极显著性差异；氯化钙酸度的变化对有效态Cu提取结果影响较小,但醋酸铵酸度变化对提取结果有较大影响。(4)提取时间对两种提取剂提取土壤有效态Cd有较大影响,在2h内,提取量随提取时间延长呈指数型增长,2h后提取量不再发生较大变化；两种提取剂的提取率都随土液比减小而增大,但增加幅度较土壤有效态Cu小。提取率随提取剂浓度的增加而增加,但提取率随氯化钙浓度的增加变化幅度较土壤有效态Cu小。土壤有效态Cd的提取率随氯化钙pH的变化较小,随醋酸铵pH变化较大,不同处理间具有显著性差异,与Cu相似。更多还原

【Abstract】 Copper and cadmium are both the major contaminated heavymetals of soil. Copper is one of the essential mineral element for plant, but large amount of copper accumulantion can also take damage to plants.Cadmium is one of the nonessential elements for plants, which is the most toxicity element as mercury. A large number accumulation of the two elements in soil can reduce the outputs and qualities of agricultural products, pose a threat to the health of humans and animals, thus received extensive attentions.The totle amounts of the elements only symbolize the feature of the resources, but cannot show the bioavailability of heavy metals in soil-plant systems.Therefor, the study of bio-available form developed and becomed the popular study in heavy mental contaminated soil fileds.This paper select the soil of one of Smelter in Jiang Xi Province as research objects and select six extractants:HCl (1#)、HO Ac (2#)、NaNO3 (3#) and CaCl2 (4#)、NH4OAc (5#)、NaOAc(6#),and use the rice grain which growthed in the pollution farmland and the ryegrass growthed in laboratory to study the corrections between the amount of Cu, Cd extractracted by different extraction agents and the contents of Cu, Cd in the rice grain and the ryegrass, and to study the stability of the results, then screening for the best extraction agents for the studied soils. At the same time, select CaCl2 and NH4OAc to study the influences of extraction time, extraction of soil solution ratio, concentration, acidity of the extractant, and other extraction conditions to the extraction of balance, following conclusions are achieved:1. The available copper in soils varied relatively larger with different types of extraction agents, the sequence of extraction contents for copper is 1#>2#>5#>4#>3#>6#. The available cadmium in soils varied relatively smaller with different types of extraction agents, the sequence of extraction contents for copper is 1#>5#>4#>2#>6#>3#. And the results of copper has relatively small coefficient of variation than that of cadium, generally, the 3# and 4# extractants has the smalllest coefficient of variation than other extractants. 2. The amounts of available copper and cadium extracted from soils by 1#,5#,4#,6# extractants have fine correlations with the contents of Cu, Cd in rice grains and ryegrass. Generally,5#,4# extractants have best extraction effective, as the extraction results of copper and cadium have significant correlations with the contents of Cu, Cd in rice grains and ryegrass, and which also have smallest coefficient of variation.3. The extraction time have great infulences to the amounts of copper extracted by the two extractants.In two hours, the extraction amounts show exponential growth with the increase of extraction time, but the extraction amounts don’t change greatly beyond two hours. The extraction amounts increased with the reduce of the ratios of solution to soil of the both two extractants. The extraction amounts increased with the elevation of extractants concentrations. The acidity range of CaCl2 don’t have great affacts to the amounts of extracted copper compared to NH4OAc.4. The extraction time have great infulences to the amounts of cadium extracted by the two extractants. In two hours, the extraction amounts show exponential growth with the increase of extraction time, but the extraction amounts don’t change greatly beyond two hours. The extraction amounts increased with the reduce of the ratios of solution to soil of the both two extractants, but the increasing range is smaller than that of copper. The extraction amounts increased with the elevation of extractants concentrations, but the increasing range with the increaseing of the CaCl2 level is smaller than that of copper. The acidity range of CaCl2 don’t have great affacts to the amounts of extracted cadium compared to NH4OAc, which is smilar to copper.更多还原