Contamination and bioavailability of heavy metals in sediments from the Yangtze River Delta Region     

Xuyin YUAN Xu DENG Zhiyong SHEN Bing LIU Ying CHEN 《中国地球化学学报》2006,25(B08):91-91

The Yangtze River Delta Region is one of the most important economic development areas in China. In the process of its industrialization and urbanization, a great deal of wastewater is poured into rivers, lakes and coasts. Researches on contamination and bioavailability of heavy metals can help us to assess the ecological risks in the aquatic environment of the Yangtze River Delta. The samples were collected from three environmental compartments including the Yangtze River, Taihu Lake, and the south coast of Jiangsu. The concentrations of heavy metals were determined by ICP-MS. Metal speciation was determined by the sequential extraction procedure modified based on Tessier＇s scheme. Among the seven elements of Cu, Pb, Zn, Cr, Cd, Co, Ni detected, the contents of Cr, Zn did not vary significantly, while Cd and Pb varied significantly. Compared to the background values （loess in the basement）, all metals detected except Co, Cr exceeded the background level. Cd had the greatest exceeding values, reaching 2 to 7 times. Ni and Pb were followed. The contents of Zn were comparatively high in lake sediments, especially in the lake bays. Ni was enriched in fiver sediments and Cu was highest in sediments from the Yangtze River estuary. Cd and Pb were concentrated in the coastal sediments. Comparatively, in space, Cr was associated with the carbonate fractions in the bay of lake. Cu-bound Fe-Mn oxides and Ni in residual form were highest in the open lake. In the river environment, Fe/Mn oxide-bound Pb, exchangeable Cd were the highest fractions. In the estuary environment, Pb and Zn bound carbonates, Cd-bound Fe-Mn oxides are the largest fractions. Cd in the exchangeable fraction, Cu-bound Fe-Mn oxides had the larger proportions in the coast. In general, the bioavailability of Cu and Cd were high in lake environment, the available Pb, Cd were remarked in river environment, and Pb and Zn were easily assimilated by creatures in estuary.  相似文献   

Enrichment of Cd and Pb and associations with grain size in sediments in Nanjing alluvial island of Yangtze River     

Hongrui MA Yuqian MAO Junfeng JI Qiling LIAO Shunsheng HUANG 《中国地球化学学报》2006,25(B08):92-93

Intermittence belts of metal contaminated sediment have been formed along the urban riverside of the Yangtze River because of rapid urbanization and industrial development during the last three decades. Baguazhou Island, the third alluvial island in the lower reaches of the Yangtze River, was chosen to assess the contaminations level of Cd, Pb, Ni, Cr, Cu and Zn in suspended particulate matter （SPM）, recent sediments and sediment-derived soils. The relations between the metal concentrations and the grain size distributions in sediments were analyzed in order to explore the association of heavy metal settling with sediment deposition. The results showed that significantly high levels of Cd and Pb in SPM dominated enrichment factors （EFs） of recent sediments in the area of Baguazhou Island. High levels of Cd and Pb were found both in the riverine sediments and in the soils. However, the average levels of Cd and Pb in sediments were almost as twice as those in soil. About 43% of all sediment samples have EFCd≥1.5 and 14% with EFCd≥2. There are about 21% of the samples with EFPb≥1.5 and none of them has EFPb≥2. Meanwhile, soil samples with EFCd≥1.5 account for 39% of all 64 samples and no one with EFPb≥1.0. Most of the sediment samples contain more than 80% of fine grains lower than 60 μm in size, and few samples located in the site where flow eroding process dominates contain fine grains lower than 30%. Correlation analysis indicated that the concentrations of Cd and Pb in the sediments have significant relationships with grain size.  相似文献   

Modeling of Regional High Ozone Episode Observed at Two Mountain Sites (Mt. Tai and Huang) in East China   总被引：3，自引：0，他引：3  

Zifa Wang  Jie Li  Xiquan Wang  Pakpong Pochanart  Hajime Akimoto 《Journal of Atmospheric Chemistry》2006,55(3):253-272

A high O₃ episode was observed during 23–25 May 2004 at two high-mountain sites reflecting the regional pattern of air pollutants over East China. This episode lasted about three days with the maximum hourly O₃ mixing ratios reaching 111 and 114 ppbv at Mt. Tai and Huang, respectively. Backward trajectories and meteorological analysis indicated that regional transport, associated with a weak high pressure system over the East China Sea, might play an important role in the formation of this high ozone episode. The nested air quality prediction modeling system (NAQPMS) was applied to investigate the formation and evolution of this high O₃ event. The comparison of model results with observations showed that NAQPMS successfully reproduced the main observed patterns of O₃ and meteorological parameters during the simulated period. The model results with emission over the Yangtze Delta and the East Central China switched on/off clearly showed that ozone and its precursors transported from the Yangtze Delta and the East Central China enhanced the high ozone episode at two sites, with a contribution of 20%–50% during the episode. In addition, based on process analysis with the model, chemical production and regional transport appeared to be the main causes of high ozone episode involving a large amount of high-ozone air masses and precursors transported from the surrounding areas. The horizontal transport is more active during the period of high ozone episode than that during the non-episode at Mt. Tai as well as Mt. Huang.  相似文献   

滇黔桂湘地区中生代复合大陆动力成矿系统特征   总被引：9，自引：0，他引：9  

方维萱  胡瑞忠  苏文超  王国芝 《大地构造与成矿学》2006,30(4):470-480

通过大陆构造地质研究和分析认为在印支期SW→NE挤压构造应力场的驱动下,本区沉积盆地内可能形成自SW→NE向的盆地流体大规模流动(滇东南→桂西北)。在燕山早期,环太平洋板块自SE→NW挤压构造应力场驱动下,本区可能形成自SE→NW向的盆地流体大规模流动(桂东南→黔西北→滇东北),且可能被限定在康滇断块隆升区西边界的以东地区。在燕山晚期,伴随大陆构造进入伸展-走滑体制和山间断陷盆地的形成,幔源热物质侵位形成盆地流体的垂向热(流)应力驱动源,这种张剪性构造为流体成矿提供了良好的构造背景。古潜山、褶皱-断裂带、逆冲断裂-褶皱带和脆韧性剪切带可能是本区主要流体圈闭构造和矿床定位构造,成矿系列可划分为改造型拉分盆地中古潜山控制的F-Fe-S-Sb-Au成矿系列、褶皱-断裂带热水再造成因的Sb-As-Hg-Au成矿系列、改造型盆地边部逆冲断裂-褶皱带中热流体成因的Ge-Ag-Pb-Zn成矿系列和脆韧性剪切带中W-Sb-Au成矿系列。  相似文献   

苏通大桥场区基岩地质新认识     

曹圣华  吴寿昌  秦宗平  肖文福 《江苏地质》2006,30(4):249-253

由于工作目的与侧重面的不同,在苏通大桥勘察中仅有的控制性钻孔获得的有关基岩地质的珍贵资料未能深入分析研究,更未予以文字或图面反映出来。在已有资料基础上,经过逻辑分析,对苏通长江公路大桥场区隐伏基岩地质作了新的补充与修订。以往文献推断的白垩系地层证实为三叠系地层;重新勾画了松散层埋深(厚度)等值线;提出了四条控制性断裂带(其他构造线均为其派生断裂)。基于上述认识,简析了有关场区生态环境地质方面的三大问题,即岩溶、地震及地热。  相似文献   

龙滩水电工程左岸B区边坡压脚工程效果分析   总被引：1，自引：1，他引：1  

刘艳辉  刘大安  李守定  程东幸 《工程地质学报》2006,14(2):239-244

龙滩水电工程左岸蠕变体B区边坡的变形和稳定是工程安全的关键。根据边坡地质与稳定性分析,边坡的整体稳定性主要取决于坡脚岩体的稳定性,因此,B区边坡治理采取了压脚的工程措施。本文采用数值模拟方法(三维离散单元法)分析了压脚前后B区边坡的整体稳定性,结果表明B区边坡压脚工程可有效控制边坡岩体的变形。同时,数值分析结果也与边坡地表和深部位移动态监测结果一致,证明了压脚工程的显著效果。  相似文献   

中国大陆科学钻探100-2000m超高压变质岩普通Pb同位素地球化学初步研究——俯冲陆壳内脱耦的证据   总被引：1，自引：0，他引：1  

董锋李曙光  李秋立刘贻灿 陈福坤 《岩石学报》2006,22(7):1791-1798

本文首次对中国大陆科学钻探工程100～2000m榴辉岩中的绿辉石和片麻岩中的长石进行了普通Pb同位素研究。钻孔上部岩段（0-800m）样品放射成因Pb同位素含量比较高且变化幅度较小（^206Pb／^204Pb=16．81-17．29，^207Pb／^204Pb=15．37-15．45，^208Pb／^204Pb=37．20-37．66），说明其原岩的U／Pb和Th／Pb或者初始Pb同位素比值比较高。钻孔中部岩段（800-1600m）发育有韧性剪切带，相应的Pb同位素比值开始降低且有起伏（^206Pb／^204Pb=16．26-16．72，^207Pb／^204Pb=15．27～15．38，^208Pb／^204Pb=36．73～37．40）、钻孔下部岩段（800～1600m）样品放射成因Ph同位素含量低但变化幅度较小（^206Pb／^204Pb=16.05～16．46，^207Pb／^204Pb：15．22～15.29，^208Pb／^204Pb=36．68～37．48），说明其原岩的U／Pb和Th／Pb或者初始Ph同位素比值比较低。实测数据同模拟数据对比表明，钻孔上、下两岩段样品普通Ph同位素不同一方面是由于继承了原岩初始Pb同位素不同，另一方面是由它们的μ值不同所致。结合氧同位素研究，本文认为800m以上和1600m以下分属上地壳和中地壳．前者是从俯冲大陆岩石圈解耦的上地壳，在大陆岩石圈俯冲过程中，上部岩片同俯冲的大陆岩石圈发生挤离，率先沿着这一个挤离面逆冲折返至浅部。下岩片是随后从俯冲岩石圈解耦的中地壳岩片，并折返至浅部下伏在先期折返的上部岩片之下。考虑到中部岩段（800～1600m）既发育有韧性剪切带又具有异常低^18O峰值（Xiao et al．，2006），挤离面是在地壳内部晚元古代的断裂带及冷水活动通道基础上发育起来的。  相似文献   

热带环流指数与夏季长江中下游旱涝的年际变化   总被引：7，自引：0，他引：7  

祝从文  何敏  何金海 《南京气象学院学报》1998,(1)

比较利用海—陆气压差和南亚季风环流定义的夏季风指数对夏季长江中下游旱涝年际变化的表征能力,根据影响东亚季风的主要热带环流定义了一个环流指数,该指数与长江中下游旱涝的年际变化存在很好的对应关系。利用１９８２年～１９９４年夏季平均可降水量距平、北半球５００ｈＰａ位势高度场距平,通过高、低指数合成和高度场与同期的热带海表温度异常的ＳＶＤ分析,结果表明,热带环流指数的高、低差异和年际变化对影响东亚夏季降水的大气环流型具有较强的分辨能力。  相似文献   

长江流域各地区环境保护水平分析   总被引：5，自引：0，他引：5  

王银彩  马智利 《云南地理环境研究》2006,18(1):87-91,96

长江流域总面积180×104km2,约占全国总面积的18.75%,跨越了东中西三大经济地带,联接了南北地方经济。在长江流域发展的历史过程中,除了社会进步与经济增长之外,也是中国环境污染较严重的地区之一。根据因子分析方法与原理,选择一系列指标,并将其归结为条件因子和治理因子,在此基础上对长江流域的环境保护水平进行了综合评价,分析了流域内各个地区之间存在的具体差异,指出对环境保护事业的高投入是环境保护水平提高的必要而非充分条件,而且各地区根据经济和污染状况的差异,应该采取不同的改进策略。  相似文献   

安徽境内长江岸带崩塌遥感调查   总被引：2，自引：0，他引：2  

杨则东  鹿献章 《国土资源遥感》1998,9(3):22-25

本文利用不同时相的航空航天遥感图像,调查了安徽省境内长江岸带类型,崩塌现状,并对江岸稳定性进行了分段描述与评价。  相似文献