Distribution and ecological risk of heavy metals in water and sediments of a river polluted by gold mining

金矿开采导致严重的水体和沉积物重金属污染。采用电感耦合等离子体质谱仪（ICP／MS）分析了金矿开采区河道32个采样点的水体和表层沉积物样品，研究了水样的溶解态及颗粒态重金属（As、Pb、Cd、Cr、Cu、Zn）组成；通过分步化学提取法研究了各重金属在沉积物中的地球化学形态组成，利用地累积指数法和潜在生态风险指数法评价了河流沉积物中重金属污染状况。结果表明：水体中Cu、Zn、As主要以溶解态存在，Ph、Cr、Cd以颗粒态为主。水体中重金属元素形态分布主要受点源污染排放影响。沉积物中，Cd浓度较低；As、Zn主要以氧化物结合态、有机物结合态和残渣态存在；Pb、Cr、Cu以有机物结合态和残渣态为主。结合地累积指数和潜在生态风险指数分析表明，Cd和Cu为主要的风险元素

Arsenic in River Sediments in Gold Mining Areas： Chemical Speciation and Release Kinetics

金矿的开采和冶炼过程会对矿区河流产生严重的重金属污染。对采集的山东省招远界河受酸性矿山废水污染河道的表层沉积样品,采用BCR连续提取法分析了砷的赋存形态;采用搅拌式直流反应器(stirred-flow reactor)进行模拟淋洗实验,研究了沉积物中砷的动力学释放过程。结果表明:沉积物存在严重的砷污染,总砷的含量在778~3 389 mg/kg之间。其中弱酸可提取态、可还原态、可氧化态和残渣态含量分别占2.6%~9.8%,18%~79%,2.4%~7.1%,8.7%~75%,赋存形态分布主要受铁锰氧化物含量、有机质含量和p H等地球化学性质控制。在0.01 mol/L的Ca(NO_3)_2溶液..

小清河口闸控感潮河段As、Sb的时空分布特征及入海通量估算

获取了2015年3个不同水情时期小清河闸控感潮河段水体的基本水质指标数据以及As和Sb的浓度数据,分析了该河段As和Sb的时空分布特征,并对其入海通量进行了估算。结果表明,小清河闸控感潮河段pH、盐度和温度的空间分布与小清河水情密切相关,小清河口地形地貌也是影响上游河水与下游海水交换的一个重要因素。枯水期和平水期水体中As和Sb的浓度沿王道闸到河口明显呈现逐渐降低的趋势,丰水期As和Sb的浓度值明显小于枯水期和平水期。沉积物中As的释放增大了孔隙水中As的浓度,最高达到24.9 μg/L。2015年小清河As的入海通量约为2618 kg,Sb的入海通量约为2677 kg

Spatiotemporal distributions of As and Sb in sluice controlled tidal reach of Xiaoqing river estuary and their land-to-ocean fluxes estimation

The basic water quality data and concentration data of As and Sb in the sluice controlled river section of Xiaoqing river in three different water conditions in 2015 were obtained. The spatial and temporal distribution characteristics of As and Sb in the river section were analyzed, and we estimated their land-toocean fluxes. The results show that the spatial distribution of pH, salinity and temperature in the sluice controlled river section of the Xiaoqing river is closely related to the water situation. The topography of the Xiaoqing river estuary is also an important factor affecting the exchange of water from the upper reaches to the lower reaches. The concentration of As and Sb in water bodies decreased gradually along the reach from Wangdao sluice to the estuary in dry period and flat period, while the concentration of As and Sb in wet period was significantly lower than that in dry and flat periods. The release of As in sediment increased the concentration of As in the pore water, with a maximum value of 24.9 mug/L. In 2015, the land-to-ocean fluxes of As and Sb were about 2618 and 2677 kg, respectively

Study on the release and vertical migration characteristics of As and Sb in farmland soil contaminated by dam break of Huashan tailings pond,Anhui,China

Recent years,tailings pond dam leakage and break accidents arising from extreme weather happened frequently,causing serious pollution to the surrounding farmland by tailings with high content of heavy metals. This study was to investigate the release and transport behavior of arsenic and antimony after the tailings entered the soil,and assess its potential pollution risks furtherly. The contents of arsenic and antimony in the surface and profile soil of a small antimony gold mining area in Anhui province were analyzed. Column leaching experiments were also carried out using the contaminated soil. The farmland soil in the study area was seriously polluted by arsenic and antimony. The contents of arsenic and antimony in the surface soil of the contaminated farmland were (14111.4) mg·kg~(-1) and (1045.2) mg·kg~(-1),respectively,which were 12 and 85 times higher than their background value in Chinese soil,and also significantly higher than the control soil. The soil pollution reached the level of heavy pollution. Despite similar geochemical properties,the vertical migration of As and Sb showed different characteristics. Antimony in soil was mainly distributed in the surface layer,and its content decreased gradually with the increase of depth. In addition to high content in surface layer (113 mg·kg~(-1)),arsenic content showed a maximum value at the depth of 60 cm (114 mg·kg~(-1)). This indicated that arsenic and antimony in surface contaminated soils would gradually migrate downward,and the migration capacity of arsenic was higher than that of antimony. Under leaching conditions of different pH and phosphorus concentrations,the release intensity of arsenic was significantly greater than that of antimony. The maximum release concentrations of arsenic and antimony were 1151 mug·L~(-1) and 10 mug·L~(-1) under different pH conditions. The maximum release concentrations of arsenic and antimony were 1277 mug·L~(-1) and 170 mug·L~(-1),respectively,when leaching with different phosphorus solutions. The application of phosphate fertilizer could promote the release of arsenic and antimony in the soil contaminated by tailings,which increased a potential ecological risk

安徽花山尾矿库溃坝污染农田土壤中As、Sb的释放及垂向迁移特征

近年来,极端天气引发的尾矿库泄露和溃坝事故频发,导致周边农田极易遭受高重金属含量的尾矿砂污染.为进一步探讨富含重金属的尾矿砂进入土壤后砷(As) 、锑(Sb)的释放及迁移行为,评估其潜在的污染风险,本研究以安徽省某小型锑金矿区周边农田为例,分析了矿区表层和剖面土壤中砷和锑的含量,并利用污染农田土壤开展了柱淋溶实验.结果表明,研究区污染农田表层土壤中As和Sb的含量分别为(141 ± 11.4) mg·kg~(-1)和(104±5.2) mg·kg~(-1),分别超过中国土壤背景值12倍和85倍,也远高于对照田表层土壤,达到重度污染水平.尽管具有相似的地球化学性质,但As和Sb在土壤垂向迁移方面表现出不同的特性.土壤中的Sb主要分布于表层,其含量随剖面深度增加逐渐降低;而土壤As含量除表层较高外(113 mg·kg~(-1)),在60 cm深度出现一个极大值(114 mg·kg~(-1)).这表明表层污染土壤中的As和Sb会逐渐向下迁移,并且As的迁移能力高于Sb.在不同pH和不同浓度磷溶液淋滤下,As的释放强度均明显大于Sb,不同pH溶液淋滤条件下As的最大释放浓度达到1151 μg·L~(-1),Sb的最大释放浓度只有10 μg·L~(-1).不同浓度磷溶液淋滤条件下As和Sb的最大淋出浓度分别为1277 μg·L~(-1)和170 μg·L~(-1).磷肥的大量施加可以促进尾矿砂污染土壤中As、Sb的释放,增大其潜在生态风险

Spatial-temporal distribution characteristics and risk assessment of heavy metals in a river flowing into the bay in a typical gold mining area

In order to study the pollution characteristics of heavy metals in Jiehe River in a typical gold mining area and propose targeted remediation measures,four sampling surveys were conducted from 2014 to 2016 to analyze the content,occurrence forms and spatial-temporal distribution characteristics of four heavy metals (Zn,As,Cd and Pb) in river water and surface sediments. The pollution levels and ecological risks of the surface sediments were evaluated using the Nemero comprehensive pollution index method and risk assessment coding method. Results showed that the concentrations of Zn,As and Cd of some sampling sites exceeded the national standards of surface water environment quality standard Ⅲ class limits,and Pb concentrations were lower than the limits. Three main pollution sources were identified along the Jiehe river,including the upstream chemical plant,the midstream Guoda Metallurgical Group tailings pond and the Jinchiling gold mine. The water quality of the Jiehe river has not been improved after the river regulation. Therefore,it is necessary to take corresponding measures to repair the three main pollution sources. The contents of Zn,As,Cd and Pb in the sediments were 218-5878,17-4177,1-67 and 35-974 mg·kg~(-1), respectively. The content of weak acid extracted form of Zn and Cd were above 60%,while the speciation distributions of As and Pb varies greatly along the river,mainly in reducible and residual forms. The results of pollution level and risk assessment showed that the sediments in the 11 sampling sites were all heavily polluted. Among the four heavy metals,Zn and Cd have the highest risk level, in 4 sample points Zn and Cd at an extremely high risk level,and As and Pb at a low risk level in most of the sample points. Therefore,pollution remediation should be focused on Zn and Cd pollution

欧-亚-非大陆季风:超级大陆与超级季风的雏形

欧洲-亚洲-非洲大陆聚集在一起,占地球陆地面积的一半以上(约56%),整体上可以近似看作是超级大陆的“雏形”;相应地,广泛分布的亚洲-非洲季风-干旱气候系统也可以近似为超级季风-干旱系统的“雏形”。对这一巨大气候体系的研究不仅本身有十分重要的理论和实际意义,同时也能够为研究潘基亚超级大陆-超级季风系统及其演化提供现代或第四纪的“相似型”。晚更新世-全新世地质记录和气候模拟结果表明亚洲-非洲夏季风气候变化主要响应北半球夏季太阳辐射变化;南北半球季风变化在岁差尺度上的相位关系近于相反;西风环流影响下的中亚干旱-半干旱区气候变化在岁差尺度上与亚洲季风也接近同相位变化;亚洲-非洲季风-干旱气候系统的这些变化在岁差尺度上领先于全球冰量的变化。总体上,似乎可以提出这样一种假说:受到地球轨道偏心率幅度调谐的太阳辐射在岁差尺度的周期波动可能是季风-干旱气候在轨道尺度上的主导“韵律”,包括潘基亚超级大陆季风气候在轨道尺度上的变化。第四纪欧洲-亚洲-非洲“超级大陆”及其季风-干旱系统本质上与潘基亚超级大陆的季风-干旱系统有着一定程度的相似性,因此研究前者是理解后者(所谓将今论古)的重要途径之一,对解译深时“碎片”化的地质记录有实际意义