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1.
The effect of land reclamation on the migration and accumulation of heavy metals and some pollutants in small rivers is determined. The study was conducted in the Middle Amur lowland in different phases of hydrological regime and at different extent of floodplain inundation. The formation of the hydrological regime in small rivers in this area is governed by the irregular annual runoff distribution. The seasonal character of flood periods requires water samples to be taken before spring flood (April) and after floods have passed (September–October), and at various extent of floodplain inundation. The field studies of water-courses were carried out in 2009–2014. The water samples were analyzed to determine the concentrations of heavy metals (iron, manganese, copper, nickel, cobalt, lead and zinc), suspended substances, organic carbon (total, dissolved, and suspended), humic and fulvic acids, and volatile organic compounds. The mobility of heavy metals in surface watercourses was shown to reflect the effect of drainage and surface runoff from soil horizons, an increase in the concentrations of suspended and organic compounds, especially, fulvic acids, which enhance their geochemical mobility. During floods, an increase in heavy metals washout from floodplain soils and the dilution of their concentrations causes the formation of a single-type concentration series of heavy metals. In addition, the processes of pollutants migration show an effect of changes in the geomorphological characteristics of floodplain–channel complexes and a decrease in flow velocity in watercourses in the areas where land reclamation was applied. Thus, all factors mentioned above lead to a decrease in water pollution index in the river.  相似文献   

2.
We investigated the effects of biostimulation and bioagumentation strategies applied to harbor sediments displaying reducing conditions and high concentrations of petroleum hydrocarbons and heavy metals. We compared the microbial efficiency of hydrocarbon removal from sediments maintained for 60 days in anoxic conditions and inoculated with acetate, sulfate-reducing bacterial strains and acetate and sulfate-reducing bacteria. All treatments determined a significant increase in the microbial growth and significant decreases of hydrocarbon contents and of redox potential values. The addition of sulfate-reducing bacterial strains to the sediment was the most efficient treatment for the hydrocarbon removal. In all experiments, significant changes of the heavy metals’ phase repartition were observed. The results reported here suggest that the biodegradation of petroleum hydrocarbons in anoxic marine sediments may be enhanced by stimulating microbial anaerobic metabolism, but care should be applied to monitor the potential changes in the mobility and bioavailability of heavy metals induced by bio-treatments.  相似文献   

3.
The aim of this paper is to show the concise chemico-physical adsorbent performance of water purification systems utilizing geo-(e.g., allophane, clinoptilolite, and smectite) and bio-polymer materials(e.g.,chitosan or cellulose nanocomposite materials) and to propose an optimal ground-water remediation technique. The performance of geo-materials is evaluated based on the individual sorption and immobilization capacities for various priority substances and pollutants(e.g., lead, zinc, cadmium, c...  相似文献   

4.
A laboratory experiment was carried out in which the flocculation products, formed from the mixing of filtered (0.4 μm) river water and seawater, were analysed. This study established that Fe, Mn, Al, Cu, Ni, Cd and Co have resolvable and well-defined estuarine chemistries. Copper, Ni, Mn and Co have salinity dependences of removal which are similar to those of dissolved Fe and humic acids. The amount of removal of the above trace metals increases between 0 and 15–18‰, after which little additional removal occurs. The extents of removal from river water are very different: Fe, 95%; Al, 20%; Cu, Ni, 40%; Co, 10%; Cd, 5% and Mn, 25–45%. The basic removal mechanism appears to be the estuarine flocculation of trace metals which exist, in part, in river water as colloids in association with colloidal humic acids and hydrous iron oxides. A qualitative model, based on this mechanism, supports the observations of this flocculation study.The results of this study give the most complete and consistent set of data presently available, from which to postulate the most important processes controlling the estuarine chemistry of trace metals. The generality of their behaviours still needs to be determined by future investigations.  相似文献   

5.
沉积物中有机质的环境行为研究进展   总被引:57,自引:5,他引:52  
朱广伟  陈英旭 《湖泊科学》2001,13(3):272-279
水体沉积物是重金属,有毒有机化合物等环境污染物及C,N,P等营养元素的汇和释放源,而有机质对灾些污染物和营养元素在沉积物中的迁移,转化等地球化学行为中起着至关重要的作用,本文就近期有关沉积物中有机质的环境地球化学行为为方面的研究进行了综述,重点评述了有关沉积物中有机质本身的来源,性质,迁移和矿化及其环境效应等方面的研究进展。  相似文献   

6.
Seasonal dynamics of total concentrations and the main forms of occurrence of heavy metals (HM) in the water mass and bottom deposits (BD) are studied in the Priplotinnyi (Near-dam) Pool of the Kuibyshev Reservoir. In the near-bottom and interstitial waters, heavy metals are mostly found in the form of complex compounds with organic and mineral ligands; the proportions of these complexes and the dominant form in the above media change from season to season. The hard skeleton of bottom deposits contains a large store of heavy metals that can be a source of the secondary pollution of water masses.  相似文献   

7.
Spodic Material for In Situ Treatment of Arsenic in Ground Water   总被引:2,自引:0,他引:2  
The leaching of chromium-copper-arsenic salts from old wood preservation sites is a threat to ground water at many places in Sweden. The installation of in situ reactive barriers is an attractive "passive' technique to prevent the further spreading of contaminants. The use of peat as a reactive barrier material has been suggested for heavy metals, but this material was expected to be unsatisfactory for arsenic (As). Therefore, the feasibility of using spodic B horizon material for the retention of arsenic was tested in laboratory column experiments. Contaminated soil was taken from an old preservation site and leached under conditions designed to imitate the field conditions. The arsenic load during the three-month duration of the test corresponded to a load at the field site during three years. The B horizon material proved to be efficient for retention of arsenic, despite the observation that As(III) dominated the As speciation. The As(III) concentration was reduced from 1 to 3 mg dm−3 to < 0.02 mg dm−3. Pure peat was, as expected, not suited as a reactive barrier for As, and a mixed B horizon/peat reactive barrier also proved unsatisfactory for the removal of As. It is therefore important to separate the B horizon material from any peat that is used to sorb heavy metals. Before applying the B horizon reactive barrier technique in the field, the effect of the naturally occurring variability of the reactive compounds should be tested. The inclusion of oxidizing agents in the barrier could possibly improve the lifetime considerably. Furthermore, the influence of the flow rate should be evaluated since the kinetics of the arsenic adsorption is relatively slow.  相似文献   

8.
9.
白洋淀沉积物-沉水植物-水系统重金属污染分布特征   总被引:5,自引:1,他引:5  
通过对白洋淀沉水植物及对应沉积物和水中Cd、Pb、As含量测定,以期揭示白洋淀沉积物-沉水植物-水系统中重金属污染状况及分布规律,明确不同沉水植物对重金属的富集能力.结果表明,地表水Cd、Pb、As浓度均符合我国地表水I类水质标准,不同采样区重金属浓度差异不显著.上覆水Pb浓度显著高于地表水和间隙水,间隙水As浓度显著高于地表水和上覆水;地积累指数法和潜在生态危害指数法评价结果表明,沉积物中重金属污染程度表现为Cd > Pb > As,Cd污染最严重,达到"轻度-偏重度"污染程度,"中等-极强"生态危害级别,As为清洁水平,不同采样区重金属污染程度表现为生活水产养殖区 > 纳污区 > 淀边缘区;沉水植物重金属富集能力表现为金鱼藻(Ceratophyllum demersum L.) > 菹草(Potamogeton crispus L.)和穗状狐尾藻(Myriophyllum spicatum L.) > 篦齿眼子菜(Potamogeton pectinatus L.).植物体内重金属含量与体内氮、磷含量呈显著正相关,氮、磷营养盐影响沉水植物对重金属的富集.  相似文献   

10.
藻类对重金属的耐性与解毒机理   总被引:23,自引:1,他引:22  
周文彬  邱保胜 《湖泊科学》2004,16(3):265-272
重金属是一类具有潜在危害的重要污染物,越来越多的重金属被排入水体,对水生生态环境构成严重威胁.藻类在长期响应重金属胁迫过程中,建立起一系列的适应机制.藻类通过控制重金属的吸收、富集、转运与解毒,使不同细胞组分中的重金属维持在正常浓度范围内.这些保护机制主要包括藻细胞的某些胞外组分与重金属结合,从而减少重金属进入胞内;在重金属诱导下藻细胞可合成金属结合蛋白或多肽;重金属诱导藻细胞合成一些代谢物使其免受伤害或修复由重金属胁迫造成的损伤;藻细胞通过液泡区室化作用使重金属远离代谢;藻细胞对重金属具有排斥与排出作用.  相似文献   

11.
This study tests the feasibility of an aquifer remediation concept proposed by Gvirtzman and Gorelick (1992) that involves the removal of volatile organic compounds (VOCs) dissolved in ground water. The principal is 10 inject air into a well, creating airlift pumping, which is used as a means of in-well vapor stripping. The partially treated water is diverted away from the well and infiltrates back to the water table, thus allowing remediation of a larger aquifer volume.
A remediation well prototype, constructed in a laboratory aquifer model, was used to demonstrate the processes involved. The removal rates of trichloroethylene, toluene, and chloroform were monitored using eight triple-level observation wells. The continuous decrease of VOC concentrations during the short-term experiment has yielded macroscopic evidence that the process offers some promise. It was found that the flow field in the saturated zone. involving the continuous water circulation between the pumping well and the recharging area, caused temporal and spatial variation in remediation efficiency.  相似文献   

12.
Sb, As, Cu, and Zn toxicity and contamination have become a growing concern in recent years. Phytoremediation, a plant based and cost effective technology, may be an effective approach in the cleanup of water contaminated by these metals. In this study, the aquatic macrophyte Eleocharis acicularis was used in laboratory and field experiments to assess its capability to accumulate Sb, As, Cu, and Zn, and thereby investigate its potential application in phytoremediation. The results showed that E. acicularis adapted well to water contaminated by these metals. The removal rates of Sb, As, Cu, and Zn in the laboratory experiment were 3.04, 2.75, 0.417, and 1.49 μg/L/day, respectively. The highest concentrations of these metals accumulated in E. acicularis after 10 days of the laboratory experiment were 6.29, 6.44, 20.5, and 73.5 mg/kg dry weight, respectively. Only 8% of As, 12% of Sb, 87% of Cu and 93% of Zn removed from the water were used by E. acicularis. The highest concentrations of Sb, As, Cu, and Zn accumulated in E. acicularis after 10 wk of the field experiment were 76.0, 22.4, 33.9, and 266 mg/kg dry weight, respectively. The results indicate that E. acicularis has the ability to accumulate Sb, As, Cu, and Zn from contaminated water.  相似文献   

13.
Modeling of Trace Organics Biotransformation in the Subsurface   总被引:1,自引:0,他引:1  
Biofilm processes are potentially important for transformations of organic micropollutants in ground water. Some theoretical hypotheses and empirical observations suggest that a concentration threshold exists for some compounds below which the concentration cannot be reduced by bacterial action. However, in the presence of one compound at a relatively high concentration, termed the primary substrate, another compound present at trace concentrations, termed the secondary substrate, can be biotransformed as well. These concepts were evaluated through laboratory column studies with several halogenated organic compounds of importance in ground water. A biofilm model can successfully describe utilization of trace substrates, and application to modeling the subsurface is discussed. A simplified batch model with first-order kinetics may be adequate for describing subsurface microbial processes when low active organism and pollutant concentrations exist over a large scale.  相似文献   

14.
大通湖及东洞庭湖区生物体重金属的水平及其生态评价   总被引:4,自引:0,他引:4  
于2005年11月采集了大通湖及东洞庭湖区湖水和水生生物样品,并测定了水和水生生物样品中重金属(Cd、Pb、Hg、As)的含量,并对湖区生物体重金属进行了污染评价.研究结果表明,大通湖及东洞庭湖区湖水中重金属含量较小,绝大部分采样点水质都属于国家Ⅰ类水标准;水生生物体内CD、Pb含量为虾>螺>鱼,Hg的含量为鱼>螺>虾,As的含量为螺>虾>鱼;而鱼类重金属含量则为底栖鱼类>中上层鱼类,肉食性鱼类>植食性鱼类.大通湖及东洞庭湖区生物体中CD、Pb的污染指数为虾>螺>鱼,Hg的污染指数则为鱼>螺>虾,As的污染指数则为螺>虾>鱼.  相似文献   

15.
Surfactant enhanced soil washing (SESW) was applied to an industrial contaminated soil. A preliminary characterization of the soil regarding the alkaline-earth metals, Na, K, Ca and Mg took values of 2866, 2036, 2783 and 4149 mg/kg. The heavy metals As, Cd, Cu, Pb, Ni and Zn, had values of 4019, 14, 35582, 70, 2603, and 261 mg/kg, respectively. When using different surfactants, high removal of Cu, Ni and Zn were found, and medium removals for Pb, As and Cd. In the case of these three metals, tap water removed more than the surfactant solutions, except for the case of As.There were surfactants with average removals (this is, the removal for all the metals studied) of 67.1% (Tween 80), 64.9% (Surfacpol 14104) and 61.2% (Emulgin W600). There were exceptional removals using Texapon N-40 (83.2%, 82.8% and 86.6% for Cu, Ni and Zn), Tween 80 (85.9, 85.4 and 81.5 for Cd, Zn and Cu), Polafix CAPB (79%, 83.2% and 49.7% for Ni, Zn and As). The worst results were obtained with POLAFIX LO with a global removal of 45%, well below of the average removal with tap water (50.2%).All removal efficiencies are reported for a one step washing using 0.5% surfactant solutions, except for the case of mezquite gum, where a 0.1% solution was employed.  相似文献   

16.
江苏省五大湖泊水体重金属的监测与比较分析   总被引:2,自引:2,他引:2  
2001—2011年(不含2004年)10年间对江苏省五大湖泊(太湖、滆湖、洪泽湖、高宝邵伯湖和骆马湖)的水体重金属浓度进行长期定点监测,按系统分组资料进行方差分析,以比较各重金属浓度在湖泊间的差异显著性,并在此基础上应用多指标综合评价法(TOPSIS法)对5个湖泊水体重金属进行综合比较.结果表明:除铜浓度外,5个湖泊间铅、镉、汞和砷4个指标浓度均存在极显著差异;5种重金属浓度湖泊内站位间均差异不显著;铅、镉和汞浓度站位内年份间差异显著或极显著.TOPSIS分析结果表明,总体而言高宝邵伯湖水体重金属污染程度最小,骆马湖水体重金属污染程度最大,洪泽湖、太湖和滆湖水体重金属污染综合评价优劣相当.  相似文献   

17.
Experimental models are used to study the poorly known function of pore waters, i.e., their role in hydrosphere pollution. This issue is studied as applied to modern bottom sediments, soil-forming grounds of the aeration zone, and impermeable clays in aquifers. The natural and technogenic geodynamic loads, accompanied by compaction and destruction of water-bearing rocks, are shown to intensify the processes of pore water pressing with the release of rock-forming elements, heavy metals, and organic substances into bottom water layers in water bodies, free soil or intermediate waters. This results in an environmental damage to water bodies, which could be used for drinking water supply and fishery. This study is of particular importance in areas of present-day oil and gas production.  相似文献   

18.
Concentrations of heavy metals in the bottom sediments of the Ivan'kovo Reservoir bays are analyzed. The role of higher aquatic plants in the processes of heavy metals accumulation and transformation in bottom sediments is studied. Uneven distribution of microelements in the bottom sediments is found to be typical of the bays, which is related to the character of heavy metals input in the bays and to processes occurring inside the bays themselves.  相似文献   

19.
The toxic action of bicomponent mixtures of phenols and heavy metals on luminous bacteria has been studied. It was established that phenolic compounds displaying properties of structural-specific agents whose influence is based on chemical reactions with receptors in mixtures with heavy metals of mercury, cadmium in low concentrations caused additive, and with the increase of metal concentration-more than additive, effects. Phenolic compounds acting as structurally-nonspecific agents (resorcinol), whose toxicity is stipulated by their physico-chemical properties, produce a less than additive effect in a mixture with heavy metals.  相似文献   

20.
Phytoremediation is an environmental remediation technique that takes advantage of plant physiology and metabolism. The unique property of heavy metal hyperaccumulation by the macrophyte Eleocharis acicularis is of great significance in the phytoremediation of water and sediments contaminated by heavy metals at mine sites. In this study, a field cultivation experiment was performed to examine the applicability of E. acicularis to the remediation of water contaminated by heavy metals. The highest concentrations of heavy metals in the shoots of E. acicularis were 20 200 mg Cu/kg, 14 200 mg Zn/kg, 1740 mg As/kg, 894 mg Pb/kg, and 239 mg Cd/kg. The concentrations of Cu, Zn, As, Cd, and Pb in the shoots correlate with their concentrations in the soil in a log‐linear fashion. The bioconcentration factor for these elements decreases log‐linearly with increasing concentration in the soil. The results indicate the ability of E. acicularis to hyperaccumulate Cu, Zn, As, and Cd under natural conditions, making it a good candidate species for the phytoremediation of water contaminated by heavy metals.  相似文献   

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