土壤样品中砷硒铬汞等元素有效态分析
作者：汤志云
院校:南京工业大学
关键字:砷;硒;铬;汞;有效态
学位：硕士
专业:应用化学
摘要:
长期以来,土壤污染问题,特别是重金属污染一直受到社会的关注。由于土壤中的重金属元素,如As、Se、Cr、Hg可通过植物吸收传递到食物链而影响人和动物的健康,因此,越来越多的科学家的开始重视有关重金属的生物有效性和控制技术的研究。作为重要的研究手段之一,元素有效态的分析技术起着关键的基础作用。 本文在系统总结As、Se、Cr、Hg等元素的地球化学性质和有效态分析技术的基础上,针对土壤中污染元素的化学特性,分别采用NaHCO3、DTPA、HCl、NH4Ac、Mehlich3、AB-DTPA等浸提剂进行了元素有效态浸提研究,通过各种浸提因素试验,取得了元素有效态分析的最佳浸提条件,建立了:As、Se有效态分析方法;Cr、Hg有效态分析方法;Mehlich3浸提剂法测定酸性土壤中多元素有效态的方法;AB-DTPA浸提剂法测定碱性土壤中多元素有效态的方法。这几组有效态分析方法,达到了经济、高效的目的。 在研究多元素有效态浸提剂的同时,采用原子吸收光度法、原子荧光光度法等现代分析技术,改善了分析方法的检出限、精密度和准确度。 为了检验元素有效态分析方法的可行性和有效性,我们分别在江苏南京镇江测区、广东珠江三角洲测区和武汉江汉平原测区作了部分应用试验,通过123件土壤和30件植物试验样品中元素全量和元素有效态含量的分析,对测区元素有效态含量的特征、比例、含量变化趋势、元素相关性以及与成土母质、不稳定相态和植物元素含量的关系等方面总结了一些规律,对深入进行农业地质和生态环境地质研究有一定指导意义。
Abstract:
For long time, the public has focused on the contamination of soil, especially the heavy metals such as As, Se, Cr and Hg. As the heavy metals in soil can be transferred into food chain by plant absorption, they may be harmful for human and animals. More and more scientists began to do the research on theirs bio-availability and controlling technique. One of those basic tools, the analysis of available form of heavy metals, was widely studied. Based on the reviewing of the geo-chemistry properties of As, Se, Cr and Hg in soils, the advance of their available form analysis and universal extractants, several analytical methods were developed: the analysis of available As and Se in soil, using NaHCO3 as extracting solution, the analysis of available Cr and Hg in soil, using diluted HCl as extracting solution, the analysis of available form of multi-elements in acid soil, using Mehlich3 as extracting solution, the analysis of available form of multi-elements in alkaline soil, using Ammonium Bicarbonate-diethylenetriaminepentacetic acid (AB-DTPA) as extracting solution. Using the developed methods, 123 soil samples were analyzed for and to investigate the levels of extractable As, Se, Cr and Hg in some contaminated or expected to be contaminated soils of Nanjing-Zhengjiang, Guangzhou and Wuhan districts.