Distribution and sequential extraction of some heavy metals in urban soils of Guiyang City,China

Sixty-two soil samples collected from different functional zones of Guiyang were analyzed for total concentrations and sequential extraction of Cr, Cu, Pb, Zn and Cd by ICP spectrometry. The average total concentrations ofCr, Cu, Pb, Zn and Cd in the soils of Guiyang were 92.9, 51.6, 44.1,139.3 and 0.28 mg/kg, respectively. The soils have been polluted by Cr, Cu, Pb, Zn and Cd to some extent in comparison with the background values of Guiyang. Significant differences were recognized in the concentrations of Cr, Cu, Pb, Zn and Cd in different functional zones. As for the sequential extraction, Cr, Cu and Zn were present mainly in the residual fraction, and Pb was present mainly in the oxidizable fraction. The reducible fraction of Cd accounts for 47.5%, and the residual fraction is lowest. The mobility and bioavailability of heavy metals follow the order of Cd〉Pb〉Cu〉Cr〉Zn.     

贵阳市地下水污染现状评价及防治对策

通过对贵阳市有关地质资料的综合分析以及实现调查、取样,根据地下水质量标准,并运用单项和综合污染指数法对贵阳市地下水进行了污染现状评价。评价结果显示贵阳市广大农村地区地下水水质较好,但人口集中的市区和工矿业密集区地下水污染较为严重。并根据综合评价结果和贵阳市环境地质条件,提出了相应的防治对策。     

Geogenic distribution and baseline concentrations of Cu and Zn in surficial soil of Guiyang, China

1 IntroductionThe term“Environmental Geochemical Baseline(EGB)”first appeared in the International Geochemi-cal Mapping Program (IGCP259) and the InternationalGeochemical Baseline Program (IGCP360) of Interna-tional Geography Contrast Program. The defin…     

Total gaseous mercury emissions from mercury-enriched soil in Guizhou, China

Guizhou is located in the Circum-Pacific Global Mercuriferous Belt, and mercury concentrations in soil in this area are enriched. In-situ total gaseous mercury （TGM） exchange fluxes between air and soil surface were intensively measured at four sampling sites in Guiyang from 21 May to 16 June, 2003, and five sites in the Lanmuchang mercury mining area in December 2002 and May 2003, respectively. The in-situ Hg flux measurement was conducted with a dynamic flux chamber （DFC） of quartz. Overall, net emissions were obtained from all sampling sites. Soil mercury concentration and solar radiation have been proved to be the two most important parameters to control mercury emissions from soil. Meanwhile, rain events can enhance mercury emission rate significantly.     

Boron isotopic geochemistry of karst groundwater in Guiyang City, China

Boron has two stable isotopes （^10B and ^11B） with relative abundances of about 20% and 80%, respectively. Boron isotopic ratios in natural materials show a huge range of variations, from -70‰ to ＋60‰, when expressed with the classical δ^11B notation. Most of these isotopic variations occur at the surface of the Earth. Hence, boron isotopic composition can be used as a sensitive tracer in geochemical study, for instance, to identify the different sources of contamination and factors controlling the salinity of groundwater. During the last decade, boron isotopes have been used to discriminate between the influences of seawater intrusion and anthropogenic discharge. But few of those researches can precisely identify the different sources of contamination. We measured the boron concentrations and boron isotopic ratios of groundwater samples collected in Guiyang City, as well as the major ions. The results indicate that the major ion composition of the groundwater in the investigated area is mainly controlled by the interactions between water and the dominant rock i.e. carbonates. All the water compositions are characterized by high concentrations of Ca^2＋, Mg^2＋, HCO3^-, SO4^2-, and NO3^-, which are the dominant contaminants. Both dissolved boron concentrations and isotopic ratios show large variations among the ground waters, from 2 μg/L to 90 μg/L and from -6‰ to ＋26‰, respectively. The boron concentrations and isotopic ratios indicate that the river across the studied city has been seriously contaminated by urban discharge. Boron concentrations of fiver water samples varied from 20 μg/L to 140 μg/L, with an average δ^11B value of ＋2.0‰. Using boron isotopic compositions and different geochemical indices allowed us to clearly identify and distinguish the two major sources of contamination, agricultural activity and urban wastewater. Both of the two sources are characterized by high boron concentrations but their boron isotopic compositions significantly differ.     

桂林市七星区土壤汞赋存形式及其污染性研究

文章对桂林市七星区五个采样片区的土壤热释汞含量、部分样品汞的赋存形式以及其污染性状进行了分析,并对主要相态汞的来源进行了简单的分析。结果发现:桂林市七星区部分区段土壤汞存在轻度的污染,污染主要源于原始岩石背景含量较高;区内土壤中汞的赋存方式多种多样,组成差异也较大,其中以硫酸汞为主的高温热态汞含量最高,其次为硫化物形态汞,再次为以氧化物形态为主的中温热态汞,而吸附态汞和低温热态亚汞及低温热态汞含量较低,所占总汞含量小于10%。     

苏州西部土壤汞分布特征及成因

在收集以往自然重砂测量、土壤测量资料的基础上,结合1∶5万土壤地球化学调查,进行苏州西部土壤中汞的分布特征及成因解析。结果表明,研究区土壤中Hg含量变化范围较大,介于0.023～5.012 mg/kg之间,平均值高达0.386 mg/kg,远高于苏州地区表层土壤及太湖水网平原表层土壤Hg含量平均值,土壤汞污染比较严重。区内辰砂矿物与土壤中Hg的空间分布具有较高的耦合性,与区内断裂构造、矿床分布有关,表明区内土壤中的汞、辰砂分布是多金属矿成生作用的产物,人类活动的影响不大。     

贵阳地区土壤Co元素分布的地球化学分析

本研究采用ICP-MS法对贵阳地区表层土壤中的Co元素含量进行分析。研究结果表明,贵阳地区表层土壤中Co元素含量的变化范围为1.03～174μg/g,平均值为21.36μg/g,Co元素含量较高的区域分布于花溪区与乌当区东风镇所属的局部地区。     

The Distrbution of Various Mercury Species in Soil

According to the mercury species with different solubilities,the analytical procedure involving sequential chemical extraction has been applied to partitioning the mercury species in soils into seven fractions.Soil samples collected from five localities in different areas (the high-mercury ares.the man-made mercury-polluted area and the reference area)were an alyzed for the seven mercury species.It is found that high mercury contents of soils can be attributed to both man-made pollution and geological processes,but the two kinds of solis show obvious differences in the distribution of their mercury species.     

The geochemical characteristics of aqueous rare-earth elements in shallow karst groundwater in Guiyang City,China

Fifty-seven shallow groundwater samples were collected from Guiyang karst basin, China, to analyze the aqueous rare-earth elements in low-water seasons and it is shown that the total amount of rare-earth elements (ΣREE) in karst groundwater is exceedingly low compared with that in carbonate rocks or weathering crusts of carbonate rocks, and ranges from 0.01 to 0.43, from 0.03 to 0.27, from 0.03 to 0.19 and from 0.05 to 1.38 μg·L-1 for dolomite, dolomitic & limestone, limestone and clastic rock aquifer, respectively. Both distributions and contents of rare-earth elements (REE) in karst groundwater reflect the lithology of host rocks or weathering crusts of carbonate rocks through which groundwater flows. The chondrite-normalized patterns show a non-flat profile with higher enrichment of slightly light rare-earth elements (LREE) than heavy rare-earth elements (HREE), prominent fractionation between LREE and HREE, negative Ce anomalies and negative or positive Eu anomalies. There is more obvious fractionation between LREE and HREE in groundwater than that in carbonate rocks and their weathering crusts due to high contents of HCO3? and PH in groundwater. In shallow karst groundwater, REE(CO3)n2n-3 (n=1 and 2) is the main inorganic species of REE. But for a clastic rock aquifer, both REESO4+ and REECO3+ are the main inorganic species of REE. Species of REE in groundwater is closely associated with the hydrochemical type of groundwater which is predominated by the lithology of host rocks, groundwater-rock interaction and weathering-pedogenesis of carbonate rocks.     

Accumulation and risk assessment of heavy metals in dust in main living areas of Guiyang City,Southwest China

Guiyang is a famous tourist city located in southwestern China. In this study, dust from eleven residential areas, seven city squares, and nine schools was collected to measure the heavy metal levels and evaluate its risk. At each sampling site, 4-5 sub-samples were taken as a bulk sample. All samples were air-dried, ground, passed through a 0.105 mm nylon sieve, digested with HNO3-HC104 to determine the concentrations of Cd, Cu, Ni, Pb and Zn by ICP-MS, and digested with 1：1 aqua regia to determine As by AFS. The results show that the concentrations of As, Cd, Cu, Ni, Pb and Zn in dust of Guiyang City follow normal distribution with means of 16.1, 1.54, 138, 47.7, 129 and 479 mg/kg, respectively. Levels of As, Cd, Cu, Ni, Pb and Zn exceed the background level of soil in Guizhou Province by 33%, 96%, 100%, 78%, 96%, and 100%, respectively. Cd, Cu, Pb and Zn are heavily accumu- lated in dust of living areas with accumulation factors of 4.10, 5.12, 4.12 and 5.51, respectively. City square pos- sesses the highest geometric means of As, Cd, Cu, Pb, and Zn. The risks of heavy metal exposure to teenagers are not obvious and in an order ofAs〉Pb〉Cu〉Ni〉Zn （Cd）.     

应用于水文与工程地质的化探新方法土壤吸附汞地球化学测量

介绍了化探土壤吸附汞地球化学测量方法的基本原理,指出土壤中汞异常具有多种来源,单一测汞方法不能区别其来源。测汞方法最重要的作用最准确指出汞气的迁移通道－基岩的断裂破碎带。因此该方法更适用于水文与工程地质勘查,特别是地下水勘查。     

Farmland mercury contamination in the vicinity of an organic chemical factory in Guizhou,China

This study assesses the level of contamination of Hg in farmland soils along the irrigating channel downstream from Guizhou Organic Chemical Factory （GOCF）, where metallic mercury is used as a catalyst to produce acetic acid. The total input of mercury into the environment, as announced by GOCF, is 140 t in the past 30 years （1971-2000）. Sampling sites were chosen based on the distance from the source of pollution--the chemical factory. A total of 39 samples were collected from the study area and analyzed for total mercury concentrations and methyl mercury concentrations. The characteristics of vertical and horizontal distributions of total mercury and methyl mercury in the study area （farmland） are described in this paper. Much attention was paid to the transformation of inorganic Hg into organic mercury species in soils as well. The results showed that the farmland has been heavily contaminated by Hg. Land cultivation activity, land utilization style and distance from the pollution source could be the dominant factors controlling the distribution of THg and MeHg. It is observed that active transformation of inorganic Hg into organic mercury species （MeHg） usually takes place in paddy soils.     

贵阳市土壤重金属污染及其潜在生态风险评价

以贵阳市区土壤为对象,研究不同功能区土壤中重金属(Cu、Pb、Zn、Cr和Cd)污染的特征,采用Hakanson潜在生态危害指数法评价了土壤中重金属的潜在生态危害。结果表明,贵阳市城区土壤重金属含量差异较大,变化幅度均高于35%。产生潜在生态危害的重金属主要是Cd,已达到中度生态危害水平,Cu、Pb、Zn、Cr显示轻度生态危害水平。贵阳市潜在生态危害综合指数(RI=90.86),表明土壤重金属污染达轻度生态危害。不同功能区潜在生态危害程度的顺序依次是工业区>公园>交通区>郊区耕地>居民区。     

武汉城市湖泊汞的环境地球化学评价

汞由于其在环境中的持久性、生物地球化学可循环性以及潜在的生态威胁性而受到格外关注。对武汉远郊、城乡结合部和市区三种环境中6个湖泊的水、沉积物和生物(鱼)中汞污染特征进行了调查采样,用原子荧光光谱仪进行了汞含量的测定。采用Hakanson提出的潜在生态危害指数法直接评价了武汉湖泊汞的生态效应。结果表明,与国家食品卫生标准鱼肉中汞含量(≤300ng/g)相比,除梁子湖乌鱼(汞含量为676ng/g)外,6个湖泊3种鱼肉中汞含量均未超标,表明武汉城市湖泊汞元素尚未造成明显的生态效应;与国家Ⅲ类水质汞含量标准(0.1μg/L)相比,除金银湖水汞含量(0.137μg/L)略有超标外,其他湖水汞含量分布在0.048～0.081μg/L之间,均在合格标准线以下,武汉地区湖水中重金属汞污染不严重,不会构成严重的环境问题;应用Hakanson评价模型,据单个金属的潜在生态危害系数,排出所研究湖泊沉积物汞污染程度的序列为:东湖>墨水湖>金银湖>梁子湖>汤逊湖>鲁湖。     

高效壤气汞捕集器研制

针对以往化探技术中壤气汞方法吸附材料吸附性不均一,以及操作过程中容易造成污染的问题,研制了多层捕汞管吸附技术与捕汞管富集器相结合的壤气汞捕集器.经标准气样品分析测试验证,结果表明:捕集器吸附性良好,稳定性高,测试性能满足各项指标.在含山昭关地热化探野外试验中显示,该捕集器能够有效吸附壤中气的微量气态汞,应用效果良好.该捕集器完善了化探样品的壤气汞富集分析和技术,具有良好的应用前景.     

土壤／沉积物中汞污染地球化学及污染防治措施研究

本文综述了汞的来源,介绍了汞的形态及形态分析方法的研究进展,讨论了影响汞吸附和解吸的主要因素,比较了对土壤/沉积物中汞污染进行风险评价的方法,提出了生物修复、减少汞污染的排放等治理我国汞污染的有效措施。最后对汞在土壤/沉积物中的地球化学行为等研究方面进行了展望。     

中国汞的地球化学空间分布特征

20世纪80年代以来中国积累了岩石、土壤和水系沉积物中的大量可靠的汞分析数据和图件,为分析汞的地球化学空间分布特征提供了依据.从空间分布上看,从中国北部到南部,从西部到东部,土壤和水系沉积物中汞的含量背景值逐渐增高,汞在以干旱荒漠区、半干旱荒漠区、黄土地区和高寒山区为主的西部和北部呈低背景,在东部的森林沼泽区和半湿润低山丘陵区为中等背景,在南部的湿润低山丘陵区、热带雨林区和高山峡谷区为高背景,尤其在以云南东南部、贵州、广西西部、湖南西部岩溶区为中心的低温成矿域内,无论岩石、土壤还是水系沉积物,汞含量背景值达到最高.一般情况下,岩石、土壤和水系沉积物之间的汞含量具有继承性,在地理空间分布上呈明显的对栽应关系,并且土壤和水系沉积物之间的汞含量具有相近性,土壤和水系沉积物较岩石更为富集汞.     

The distribution characteristics of heavy metals in Guiyang urban soils

Guiyang is located in southwestern China,which is a famous tourism city,and is awarded the title of"the Summer Capital of China".A study on heavy metals in Guiyang urban soils was conducted.The results showed that the concentrations of Cd,Cu,Ni,Pb and Zn in Guiyang urban soils are significantly higher than their background values and Cu,Zn and Pb in Guiyang soils are accumulated seriously.The distribution characteristics of heavy metals in 3 districts are described as follows:the level of heavy metals in soils follows the order of Nanming District> Yunyan District>Xiaohe District.The spatial distribution of metals in urban soils of Guiyang shows that the level of metals in the central and eastern parts of Guiyang is relatively high,and its characteristics are attributed to the influence of commercial activities,heavy traffic and industrial emission.Compared with some other cities in China,Guiyang is characterized by relatively high accumulation level of Cd,Cu,and Zn in its soils.     

淮南采煤沉陷区土壤中汞的时空分布特征

以淮南采煤沉陷区土壤为研究对象,测试分析了样品中汞的含量,结合土壤pH值、有机质含量特征,探讨了采煤沉陷区土壤中汞的时空分布特征。结果表明：与未沉陷区土壤相比,沉陷区土壤有机质破坏严重,最高下降了46%;采煤沉陷区土壤中汞的含量为0.013~0.050 mg/kg,平均值为0.027 mg/kg,69.7%的采样点超过了淮南市土壤背景值;沉陷8 a后土壤汞含量最高,为0.033 mg/kg,是未沉陷土壤汞含量的1.74倍,且随着沉陷时间的增加,土壤中汞存在富集趋势;水稻土壤汞富集能力最高,高于玉米和大豆土壤;在垂直剖面上,汞含量由表层向下依次降低;且汞与pH值表现出显著负相关,有机质与汞显著正相关。