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在划分小秦岭金矿区水系流域的基础上,研究了不同水系沉积物中Hg、Pb、Cd、Cr、As、Cu、Zn七种重金属的含量水平、分布特征;从各个元素的主要来源出发,分析了重金属含量水平高低不同的原因,探讨了金矿开发对重金属含量变异的影响,提出影响水系沉积物重金属赋存、迁移的相关因素.结果发现:①从地域上看,小秦岭北麓水系沉积物重金属含量普遍高于南麓,而在北麓表现出“中间高、两侧低”的特点;②从元素含量差异看,小秦岭金矿区水系沉积物中Pb含量最高且偏离背景值的程度最大,其次是Hg,而Cr、As继续保持了低背景值的趋势. 相似文献
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大冶铜绿山铜铁矿床尾矿砂中重金属与微量元素环境地球化学特征研究 总被引：6，自引：1，他引：5
为了解铜绿山铜铁矿床尾矿砂中重金属元素的释放迁移地球化学过程及其扩散范围,运用ICP.MS对大冶铜绿山铜铁矿床尾砂库的尾矿砂及其相关的水系沉积物和土壤中重金属元素、稀土元素进行了测试分析.环境地球化学研究发现,研究区重金属元素在尾矿砂垂向剖面和水系沉积物中具有较明显的垂向和横向空间分布规律;尾砂库西北边水稻田土壤明显受到Cu、Zn、Cd等重金属元素的污染,稀土元素分布模式及微量元素比值研究揭示了污染原因可能是水稻田土壤继承了附近废弃的选矿厂和矿体的特征;尾矿砂和水系沉积物稀土元素分布模式及微量元素比值的变化规律,在一定程度上可以解释重金属元素在垂向和横向空间上的分布特征. 相似文献
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长江上游是整个长江经济带的重要生态屏障。以长江上游攀西大梁子铅锌矿区水系沉积物为研究对象,查明了重金属元素含量的空间分布特征,分析了重金属来源,探讨了在不同pH条件下重金属的淋滤规律,并进行了生态风险评估。研究结果显示:攀西大桥河流域水系沉积物中重金属的空间分布极不均匀,其含量明显要高于长江水系沉积物中重金属的平均含量;重金属生态风险属于很强风险,Hg和Cd呈高度富集、严重污染;Pb和Zn呈中度富集、中等污染。淋滤实验结果表明Pb、Zn、Cd在酸性和中性条件下淋滤浓度先快速下降,后逐渐趋于平衡,而As在快速下降后又有缓慢升高的趋势。大桥河流域水系沉积物中As、Cd、Pb、Zn主要来源于大梁子铅锌矿的采选活动,Hg为岩石风化和土壤剥蚀来源,而Cu和Cr主要为农业和工业活动来源。综合对比发现,攀西成矿带铅锌矿周边土壤富Cd而贫Cr,此外Cd、Pb、Zn、Hg是主要潜在污染物,且生态风险程度较高。 相似文献
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金沙江(攀枝花段)水系沉积物中重金属的形态特征 总被引：2，自引：0，他引：2
采用连续提取法,并用原子吸收光谱法进行分析研究了金沙江攀枝花段水系沉积物中重金属的形态及分布特征。研究发现:①各重金属的形态以残渣态为主,离子交换态含量很少;②各元素的形态有自己的特点。铜在有机硫化物结合态中的含量较高,钴在碳酸盐结合态中的含量较高,铅锌钴的铁锰氧化物结合态均较高;③有效态对水环境质量具有潜在的危害。 相似文献
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以金矿开发影响的黄河二级支流太峪水系沉积物为研究对象,沿河采集16个表层沉积物样品,分层采集垂向剖面10件水库沉积物样品,测定了样品中重金属元素Hg、Pb、Cd、Cr、As、Cu和Zn的含量,采用Hakanson潜在生态指数法和Tomlinson污染负荷指数法评价重金属元素污染程度和潜在生态风险。结果表明,矿业活动是太峪水系沉积物重金属元素污染的主要因素;变异系数、富集系数和最高污染系数均反映Hg、Pb、Cd是太峪水系沉积物的特征污染重金属元素,Cr和As的质量分数接近地区背景值;太峪水系表层沉积物受到重金属元素的极强污染,山区段污染较山外更严重;整个流域的Hg、Pb、Cd具有很强的潜在生态危害,Cr、As、Zn的潜在生态危害轻微;太峪水系沉积物垂向各层沉积物都受到重金属元素的极强污染,生态问题以Hg、Pb、Cd的潜在生态危害为主,其污染和生态危害程度都高于流向上的沉积物。潜在生态危害指数评价突出了不同元素的毒性和危害程度,而污染负荷指数法侧重于样本空间上的污染程度,二者互补使用有利于实际问题的全面评价。 相似文献
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大冶铁山地区河流水体及水系沉积物中重金属元素分布特征 总被引：7，自引：3，他引：7
矿产资源的长期勘探、开采和冶炼活动给大冶铁山地区的自然生态环境造成了严重破坏.对该区西港河、东港河河水和水系沉积物中重金属元素分布特征的研究结果表明,该区矿山开采和冶炼活动形成的重金属污染元素主要为Cd、As、Zn;其主要污染源为冶炼厂排放的废水,其次是采矿废弃物堆积渗漏水;重金属元素在河水与水系沉积物中的空间分布特征较相似,但水系沉积物中元素质量分数比河水中的普遍增高,元素变化的剧烈程度加剧. 相似文献
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The water ecosystem of the Vyshny Volochek Reservoir is characterized based on the study of the distribution of heavy metals speciations in the solid phase and pore waters of bottom sediments. Using the sequential extraction procedure, it is shown that Mn is mainly present in exchangeable and carbonate-bound forms; significant roles for Fe, Zn, Pb, and Co are played by forms that are bound to iron and manganese hydroxides and Cu and Ni are mainly bound to organic matter. Thermodynamic calculations have established the prevailing share of the following forms in pore waters: free ions for Zn, Ni, Co, and Cd, carbonate complexes for Pb, and fulvic complexes for Cu. It has been revealed that the speciation forms of heavy metals in bottom sediments depend on the lithological features and content of organic matter in sediments. 相似文献
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Competitive adsorption,release and speciation of heavy metals in the Yellow River sediments,China 总被引：2，自引：0，他引：2
Qingyun Fan Jiang He Hongxi Xue Changwei LÜ Ying Liang Saruli Ying Sun Lili Shen 《Environmental Geology》2007,53(2):239-251
The competitive adsorption and the release of selected heavy metals and their speciation distribution before and after adsorption
in the Yellow River sediments are discussed. The adsorption of metals onto sediments increases with increasing pH value and
decreases with increasing ionic strength. The competitive coefficient K
c and the distribution coefficient K
d are obtained to analyze the competitive abilities of selected heavy metals, which are ranked as Pb > Cu >> Zn > Cd. The competition
among selected heavy metals becomes more impetuous with increasing ion concentration in water. Speciation analysis was done
by an improved analytical procedure involving five steps of sequential extraction. Cu, Pb and Zn were mainly transformed into
the carbonate-bound form (50.8–87.7%) in adsorption. Most of (60.7–77.3%) Cd was transformed into the exchangeable form, and
the percentage of carbonate-bound Cd was 19.7–30.4%. The release reaction was so quick that the release capacity of selected
heavy metals from sediments to aqueous solution reached half of the maximum value only in 30 s. As opposed to adsorption,
the release capacities of selected heavy metals were ranked as Cd > Zn >> Cu > Pb. In this study, Cd produces the most severe
environmental hazards, because its concentration in the release solution is 85.8 times more than the human health criteria
of US EPA. 相似文献
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A field study was conducted to clarify the effect of rhizosphere processes on the accumulation and partitioning of heavy metals
(Pb, Zn, Cu, Cr, Cd and Ni) in mangrove sediments. Metals were fractionated by a sequential extraction procedure into three
chemically distinct fractions: water soluble, exchangeable and carbonate bound (B1), Fe–Mn oxide bound (B2), and organic and
sulfide bound (B3). Results indicate that rhizosphere processes tend to increase the metal concentrations in the rhizosphere
sediments. However, plant uptake may result in the decrease of the metal concentrations in the rhizosphere sediments when
the metal concentrations are relatively low in the bulk sediments. Compared with the bulk sediments, the rhizosphere sediments
have low concentrations of heavy metals in the B1 and B2 fractions and high concentrations in the B3 fraction. Either an increase
or decrease in the residual fraction of heavy metals in the rhizosphere sediments may appear, depending on whether the formation
of the refractory metal-organic compounds or the activation of the residual fractions dominates. Results also indicate that
mangrove plants absorb and store non-essential metals in the perennial tissues, thus reducing the export of non-essential
metals via leaf litter transport. Mangrove plants are excellent candidates for phytostabilization of heavy metals in intertidal
substrates. 相似文献
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A sequential extraction procedure was carried out in columns using reagents that are known to be reliable from batch tests. The intention was to distinguish between different chemical forms of iron and heavy metals in samples from reduced porous aquifers, which demands anaerobic conditions for the extraction procedure and the determination of small amounts of reactive mineral phases in a quartz dominated sediment system. By means of the developed method, anaerobic conditions can be guaranteed in the columns, which could not be realized to full satisfaction in batch tests that were carried out in a glove box. In order to distinguish between the fractions that were water soluble, exchangeable, bound to carbonates and bound to hydroxides, different reagents were pumped through the sediments and sampled after passage of the columns. Sediment samples of 10 kg each were investigated in this way. The extraction steps were known to be complete when analyses revealed that no further major and trace elements were leached out of the columns. This approach enabled well-adjusted amounts of reagents to be used. By means of the sequential extraction procedure in columns the composition of even small amounts of reactive mineral phases can be determined successfully, which contributes to a deeper understanding of the hydrogeochemical processes in aquifers. In batch tests this accuracy cannot be reached because of the surplus of the extraction solution in relation to the amount of sediment (higher solution-sediment ratio). Furthermore, larger samples are much more representative of the composition of the aquifers than smaller ones and the heterogeneity of the sediment does not limit the accuracy of the results as much as in batch tests. In addition, the technique of flushing sediment in a column is much more typical for the situation in an aquifer than suspending a few grams of a sample in the extracting reagents in batch extraction tests. In order to demonstrate the methodical improvements and field applications, the newly developed method was used to investigate the changing binding forms and mobility of iron and trace metals in samples from a lignite overburden dump, which are influenced by pyrite oxidation processes (acidification) followed by the addition of crushed limestone (neutralization) (see "Sequential extraction procedure in columns. Part 2: Application of a new method"). 相似文献
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Heavy metals content and distribution in the surface sediments of the Guangzhou section of the Pearl River,Southern China 总被引：2，自引：2，他引：0
The long-term industrialization and urbanization of Guangzhou city may lead to heavy metal contamination of its aquatic sediment.
Nevertheless, only few studies have been published on the distribution and contamination assessment of heavy metals in this
urban river sediment. Thus, the major objective of this study was to quantitatively assess contamination of heavy metals and
their chemical partitioning in the sediments of the Guangzhou section of the Pearl River (GSPR). Surface sediment samples
were collected at 10 sites in the main river and 12 sites in the creeks of the GSPR. The total content of Cd was determined
by graphite furnace atomic adsorption spectrometry (GF-AAS), and content of Cr, Cu, Pb and Zn was determined by inductively
coupled plasma atomic emission spectrometry (ICP-AES). The chemical partitioning of these heavy metals in the sediments of
the main river was determined by the sequential selective extraction (SSE) method. Results indicated that the average total
concentrations of Cd, Cr, Pb, Cu and Zn in the sediments of the main river were 1.44, 63.7, 95.5, 253.6 and 370.0 mg/kg, respectively,
whereas they were 2.10, 125.5, 110.1, 433.7 and 401.9 mg/kg in the sediments of the creeks. The sediment at M4 and C9 sites
was heavily contaminated with about 8 and 11 of toxic unit, respectively. Cr, Cu, Pb and Zn were mostly bound to organic matter
and in the residual phase, whereas Cd was mostly associated with the soluble and exchangeable phase and the residual phase.
The mobility and bioavailability of Cd, Zn and Cr in the sediments of the main river were relatively higher than Cu and Pb,
due to higher levels in the soluble and exchangeable fraction and the carbonate fraction. The potential acute toxicity in
the sediments of the main river and creeks was mainly caused by Cu contamination, accounting for 21.7–37.1% and 16.9–46.3%
of the total toxicity, respectively, followed by Zn and Pb. Adverse biological effects induced by heavy metals would be expected
in the sediments of the GSPR. Therefore, the sediments of the GSPR, especially at M4 and C9 sites, need to be remediated to
maintain aquatic ecosystem health. 相似文献
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滇西沘江沉积物剖面重金属元素分布特征 总被引：3，自引：0，他引：3
采用连续提取法测定流经兰坪金顶铅锌矿区的沘江3个沉积物剖面中重金属元素的含量,分析Pb、Zn、Cd和As在流域的分布特征和在沉积物剖面中的分布特征。结果表明,距矿山75km的河段沉积物中,浅层沉积物中4种金属元素均污染严重,金顶铅锌矿是沉积物中重金属元素的主要来源,随着矿山开发规模的不断扩大,污染程度加深。4种重金属元素中Cd活性态比例高,且污染程度最强、范围最广、深度最大,Zn、Pb次之,As污染相对较轻、范围较小。潜在生态危害指数法研究结果表明,浅层沉积物中重金属元素表现出中等—很强的生态风险性,产生生态危害的主要重金属元素是Cd,其后依次是Pb、As和Zn。 相似文献
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河口沉积物—水界面重金属生物地球化学研究进展 总被引：15，自引：1，他引：15
河口区既是人类排污物的主要汇集地，又是单向流体和双向流体相互作用的场所，三者构成一个复杂而多变的地球化学物理场。在这里因一定的物理，化学和生物化学作用使来自陆地的重金属污染物从水体中沉降下来，进入底部沉积物即积累过程，又会因类似的作用使这些金属从沉积物中活化而再次进入水体即释放过程，产生所谓的“二次污染”，河口沉积物水界面过程调控着这一体系的方向与限度。 相似文献
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城市污泥接种堆置处理对重金属的形态及其生物有效性的影响 总被引：1，自引：0，他引：1
污泥堆肥化后的土地利用是污泥处理处置的重要方法之一。经过对荆马河底泥接种堆置处理,揭示出污泥中重金属的形态发生明显的变化。荆马河底泥中的重金属污染物主要以结合态和残渣态的形式存在,水溶态和交换态的量很小,经接种堆置处理后,水溶态和交换态量大幅削减,结合态和残渣态量有所增加,总量变化不大,生物学方法和化学方法测定都表明,处理后的底泥生物毒性有明显降低,重金属的生物有效性降低。 相似文献
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太湖MS岩芯重金属元素地球化学形态研究 总被引：21，自引：4，他引：17
采用BCR三步提取法对太湖MS岩芯沉积物中Cu、Fe、Mn、Ni、Pb和Zn等6种重金属元素的化学形态进行了研究.结果表明,有效结合态的Cu、Ni和Pb主要以有机物及硫化物结合态、Fe-Mn氧化物结合态存在,Fe和Zn主要以Fe-Mn氧化物结合态存在,Mn主要以可交换态及碳酸盐结合态存在;Fe-Mn氧化物结合态的Ni、Pb和Zn与可还原态的Mn有较好的正相关关系,有机物及硫化物结合态的Cu、Mn、Ni、Pb和Zn与有机碳含量有较好的正相关关系;重金属形态分布体现了重金属元素地球化学性质的差异,以及重金属形态含量与沉积物理化性质的关系.沉积岩芯重金属元素形态垂向变化规律及次生相富集系数表明,Cu、Mn、Ni、Pb和Zn在沉积岩芯13～4 cm有效结合态含量较稳定,为自然沉积;4～0 cm有效结合态含量明显升高,存在一定程度的人为污染.根据137Cs测年结果判断,沉积岩芯Cu、Mn、Ni、Pb和Zn等重金属污染开始于20世纪70年代末期,主要污染元素及污染历史与太湖流域污染工业类型及经济发展阶段相吻合. 相似文献