Organochlorine pesticides in soils under different land usage in the Taihu Lake region, China

A field study was conducted in the Taihu Lake region, China in 2004 to reveal the organochlorine pesticide concentrations in soils after the ban of these substances in the year 1983. Thirteen organochlorine pesticides (OCPs) were analyzed in soils from paddy field, tree land and fallow land. Total organochlorine pesticide residues were higher in agricultural soils than in uncultivated fallow land soils. Among all the pesticides, ΣDDX (DDD, DDE and DDT) had the highest concentration for all the soil samples, ranging from 3.10 ng/g to 166.55 ng/g with a mean value of 57.04 ng/g and followed by ΣHCH, ranging from 0.73 ng/g to 60.97 ng/g with a mean value of 24.06 ng/g. Dieldrin, endrin, HCB and α-endosulfan were also found in soils with less than 15 ng/g. Ratios of p,p'-(DDD DDE)/DDT in soils under three land usages were: paddy field ＞ tree land ＞ fallow land, indicating that land usage inlfuenced the degradation of DDT in soils. Ratios of p,p'-(DDD DDE)/DDT ＞1, showing aged residues of DDTs in soils of the Taihu Lake region. The results were discussed with data from a former study that showed very low actual concentrations of HCH and DDT in soils in the Taihu Lake region, but according to the chemical half-lives and their concentrations in soils in 1980s, the concentration of DDT in soils seemed to be underestimated. In any case our data show that the ban on the use of HCH and DDT resulted in a tremendous reduction of these pesticide residues in soils, but there are still high amounts of pesticide residues in soils, which need more remediation processes.     

土壤重金属快速监测技术研究与应用进展

土壤重金属污染已经日益成为社会的主要环境污染问题之一,土壤重金属快速监测技术对于土壤重金属污染的快速有效筛查与监控具有重要意义。介绍了近年来国内外土壤重金属快速监测方法,并阐述了相关土壤重金属快速监测仪器的研究现状。在土壤重金属快速监测领域,X射线荧光光谱技术优势明显,激光诱导击穿光谱技术亦发展迅速,基于免疫学、酶抑制原理的快速监测技术正处于发展阶段。随着快速监测技术理论和方法的不断完善,土壤重金属快速监测仪器朝着高精度、小型化、智能化的方向发展,在区域性土壤重金属含量评估方面的应用将逐步拓展。     

华北平原潮土酸度特征与酸化敏感性的初步探讨

采集华北平原潮土样品对其酸度特征和酸化敏感性进行了初步探讨.结果显示,过量施用氮肥导致的硝酸盐积累是华北平原潮土pH值下降的重要原因,硝酸根与土壤pH值呈显著负相关.碳酸钙溶解是当前潮土缓冲酸化的主要过程,决定着潮土对外界酸输入的响应方式和敏感程度.随着酸输入量的增加,低碳酸钙土壤的pH值迅速下降,但高碳酸钙的石灰性潮...     

沙土不同有机组分对磷的解吸特征影响

采用平衡解吸法研究了沙土不同有机组分对磷的解吸附特征影响。结果表明,通过过氧化氢去除有机质后的沙土使磷的解吸比例（Dr=0.94）大幅度增加,解吸迟滞性指数（TⅡ=0.05）显著降低;有机质是影响磷在沙土上解吸特征的重要因素;磷在橡胶态胶体（轻组有机组分）上的表面分配作用吸附是导致解吸比例（Dr=0.81）增大,解吸迟滞性指数（TⅡ=0.05）减小的原因;稳结态腐殖质中的胡敏酸在对磷的吸着和滞留过程中发挥重要作用,HⅡ＋HⅢ组（Dr=0.57、TⅡ=0.30）;磷在紧结态腐殖质所形成的团聚体结构中引起的团聚体结构不可逆形变是导致磷的解吸比例（HⅢ组Dr=0.24）降低,解吸迟滞性指数（HⅢ组TⅡ=0.49）增大的根本原因,考查土壤磷的解吸特征不但要考虑有机质的含量,更要考虑有机质的存在形态,它也是影响土壤磷解吸特征的重要因素,轻组有机组分、重组有机组分、以及重组有机组分中的稳结态腐殖质、紧结态腐殖质所携载的吸附态磷进入水体后对上覆水体的释放通量可分别按其饱和吸附量的81%、66%、57%和24%进行估算。     

荔枝叶片与土壤常量元素质量分数年周期变化研究

从１９９７年开始,对荔枝叶片和土壤常量有效养分质量分数、ｐＨ值的年周期变化进行了研究。通过统计学分析,初步探明叶片各元素质量分数季节性变化的模式及其特点,以及土壤有效养分质量分数、ｐＨ值年周期变化的趋势;分析了年周期变化中叶片与土壤分析值之间的相关性。     

陪伴阴离子对土壤专性吸持铜的影响

本文采用流动法研究了陪伴阴离子对红壤、黄棕壤专性吸持铜的影响。实验结果表明:陪伴阴离子不同时,土壤专性吸持铜的机理亦不同,用一级动力学方程拟合吸持实验数据,结果表明:土壤专性吸持铜过程较为复杂,为多种吸持机理并存。     

酸化对茶园黄棕壤CEC和粘土矿物组成的影响

用采自江苏溧阳种茶13 a和34 a的茶园黄棕壤表土和种茶54 a的茶园土壤剖面研究了酸化对土壤黏土矿物组成和阳离子交换量（CEC）的影响。结果表明：种茶13 a和34 a,表层土壤发生明显酸化,但土壤2∶1型黏土矿物的质量分数和CEC均与荒地土壤相似,说明酸化没有对黏土矿物转化和CEC产生明显影响。但种茶54 a后土壤发生进一步酸化,表层和表下层土壤pH降至3.79和3.70。土壤2∶1型黏土矿物质量分数随采用深度的增加而增加,高岭石质量分数呈相反的变化趋势。说明表层和表下层土壤的严重酸化加速土壤2∶1型黏土矿物向1∶1型高岭石的转化,这导致表层和表下层土壤CEC显著减小。     

山东省主要果园土壤中Cu、Zn的形态、含量及分布

对我国山东省主要果园土壤中的Cu、Zn元素的形态、含量及分布进行了研究。结果表明 :果园土壤中Cu、Zn元素的全量高于一般粮田土壤。在不同土壤类型中 ,形态分布各具特点 ,Cu元素在棕壤和褐土中的形态分布趋势一致 ,为矿物态 >有机态 >沉淀态 >交换态 ,在潮土和砂姜黑土中一致 ,为矿物态 >沉淀态 >有机态 >交换态 ;而Zn元素在这 4种土壤中的分布趋势相同 ,均为矿物态 >沉淀态 >有机态 >交换态。土壤中交换态的Cu、Zn含量随土壤pH值的增大而减小。Cu、Zn某些形态的含量与土壤中全量间有一定的相关性 ,其中沉淀态Cu与总Cu的关系较为紧密 ,2者呈极显著相关 ;矿物态Zn与总Zn也呈极显著相关。     

The effect of turbation on zinc relocation in a vertical floodplain soil profile

Turbation is hypothesized to affect the redistribution of heavy metals in polluted floodplain soils by effects on mobility. This hypothesis was tested in microcosms by turbation of zinc-spiked sediment top layers. Manual turbation caused a fast decrease of the zinc content in the upper 15 cm of the soil, even though turbation was only applied to the upper two centimetres. It was especially zinc attached to colloid and organic matter particles that was redistributed from the top layer. Percolation processes resulted in the attached zinc being drained to depths of more than 15 cm. The decrease in zinc content of the topsoil was even stronger in combination with inundation. No indications were found for the redistribution of zinc as a result of an increase of the extractability with 0.01 M CaCl2 or changes in pH. The findings suggest that mechanical turbation and bioturbation may redistribute heavy metals from topsoils in polluted floodplains just after inundation as observed in these turbation experiments.     

长江下游地区新近沉积土动剪切模量比和阻尼比的试验研究

通过对长江下游地区南京、苏州、常州、徐州、泰州、盐城、扬州、无锡、镇江、张家港、连云港、启东、常熟、江阴、宿迁等15个城市的淤泥质粉质粘土、粘土、粉质粘土、粉质粘土与粉砂互层土、粉土、粉细砂和粗砂等七类新近沉积土共计275个原装土样历时3年的自振柱试验研究,给出了长江下游地区七类新近沉积土的动剪切模量比 G/Gmax和阻尼比λ与剪应变幅值γ变化的平均曲线的拟合曲线、包络线及其参数的推荐值。由于未见报道其他研究者对长江下游地区新近沉积土动力参数的系统研究,该研究成果有利于加深对该长江下游地区各类新近沉积土动力特性的认识,并对该地区各类工程建设的工程场地地震安全性评价工作具有一定的借鉴和参考价值,且有利于推动长江下游地区工程场地地震安全性评价工作的开展。