【作者】 杨玉峰；

【导师】 黄标； 黄耀；

【作者基本信息】 南京农业大学 ， 环境科学， 2008， 硕士

【摘要】 随着全球经济的快速发展,工业化进程加快,以及农业生产方式的变革,含重金属的污染物通过各种途径进入环境,尤其以土壤居多。土壤重金属的富集会影响作物品质,进而对人类健康产生威胁。本文以长江三角洲地区经济快速发展的张家港市为研究区域,通过稻麦和土壤样品的采集,研究了该地区稻麦籽粒中重金属元素的含量及其空间变异性,并初步建立了稻麦重金属积累模型,这为该市农产品质量安全的评价和针对性农业管理措施的开展提供了重要的基础资料和参考依据。结果表明:1.目前,张家港局部地区存在着稻麦籽粒Pb和小麦Cd超标的现象。稻麦籽粒Cu和水稻Cd在某些工厂企业周围含量较高,应当引起关注。2.空间分布上,水稻重金属Cu、Pb含量在雏形土地区明显高于人为土地区,而水稻中Cd的空间分布则相反;小麦Cu、Cd的空间分布为人为土高于雏形土,小麦Pb与此相反。3.土壤重金属Cu、Cd全量对稻麦Cu、Cd含量和富集有着明显的影响,同时,土壤Pb含量对小麦Pb含量和富集有着明显的影响。对Cd元素而言,土壤pH的变化对稻麦籽粒中Cd元素的富集有明显的影响。4.工业活动导致的土壤重金属含量异常对稻麦籽粒中元素含量影响比较突出,不同类型的工厂企业对水稻重金属的影响不同,化工类企业周围的稻麦重金属Cu和Cd含量要明显高,稻麦重金属Pb在冶金类企业周围的含量要明显高。5.作物中重金属含量及其空间分布受土壤重金属含量、土壤性质、作物及重金属种类等诸多因素的影响。同作物的吸收能力、不同重金属的迁移能力的强弱也影响着作物对土壤中重金属的吸收。对于重金属元素Cu和Cd来说,两种作物对其吸收能力的强弱为:小麦＞水稻;而对重金属元素Pb来说,则为:水稻＞小麦。对于不同的重金属种类来说,小麦对三种重金属元素的吸收能力的强弱为:Cd＞Cu＞Pb,水稻为:Cu＞Cd＞Pb,因此,可以根据不同作物对不同重金属的吸收特性,在某种重金属聚集严重的区域种植吸收能力弱的作物,可有效地防止作物重金属超标,而危害人类健康。6.通过逐步回归所得到的稻麦籽粒重金属统计模型,具有显著的统计学意义。更多还原

【Abstract】 With rapid global economic development and industrialization, as well as changing agriculture practices, heavy metal pollutants are introduced to the environment, especially the soil, in various ways. Plant biology and human health are negatively impacted by highly concentrations of heavy metals in their surroundings.In this study, the spatial variation of copper (Cu), lead (Pb), and cadmium (Cd), in rice and wheat grains, were studied by collecting soil and crop samples in Zhangjiagang County of the Yangtze River Delta in China, and primary statistical models of heavy metal accumulation in rice and wheat grain were developed. These results can provide important basic information and reference for assessing security of agricultural product quality and performing effective agricultural management in the region. Results are described as follows:1. Pb and Cd contents in some rice and wheat samples significantly exceeded the National Food Health Standards (NFHS) (GB2762-2005). Most of samples which exceeded the standards appeared in the areas near industries. The Cu in rice and wheat, and Cd in rice have no threat to human health at present, but accumulation of Cu and Cd in the areas near industries should be closely monitored.2. Spatially, Cu and Pb content in rice was higher in Anthrosols than Cambosols and the converse was true with respect to Cd (p<0.05); Cu and Cd content in wheat was higher in Cambosols than Anthrosols, and for Pb was higher in Anthrosols than Cambosols.3. The accumulation of Cu and Cd in rice and wheat were significantly affected by their background level in the soil, as was Pb in wheat. Accumulation of Cd was affected by soil pH.4. The heavy metal content in rice and wheat was also dependant on the types of industries presented. Cu and Cd were higher in areas close to chemical industries, while Pb was higher in areas close to metallurgy industries.5. Content and distribution of heavy metal in crops is influenced by their concentration in the soil, soil properties, types of crops, and heavy metal properties. Crop uptake of heavy metals from soils was influenced by crop types and transfer ability of heavy metals. For Cu and Cd, crop uptake was higher for wheat than rice, and higher for rice than wheat for Pb. For different heavy metals, metal uptakes by wheat was in the following order: Cd > Cu > Pb; uptake by rice was in the following order: Cu > Cd > Pb. Therefore, crops with weak uptake towards certain heavy metals should be paired with soil affected by that particular heavy metal to reduce the impact on human health.6. The heavy metal models in rice and wheat grains by stepwise regression can fit the heavy metal contents in rice and wheat grain estimations on Anthrosols and Cambosols in Zhangjiagang.更多还原