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1.
This report presents the results of a research programme designed to examine the engineering and environmental acceptability of stabilizing municipal solid waste (MSW) combustor ash for artificial reef construction. Municipal solid waste combustor ash was combined with Portland cement to form solid blocks using conventional construction block making technology. the resultant stabilized combustor ash (SCA) blocks were used to construct an artificial habitat in Conscience Bay, Long Island Sound, New York and compared to identical concrete blocks, fabricated using natural aggregates. Over a 4.5 year period divers periodically returned to the site to monitor the interaction of SCA blocks with the marine environment and compare the performance of these blocks with the concrete control blocks. Results show that the SCA blocks retain their strength after prolonged sea water exposure. Contaminants of environmental concern, including metals, dioxins and furans, were retained within the cementitious matrix of the SCA blocks after prolonged sea water submersion. in addition, organisms growing on the surfaces of the SCA blocks did not accumulate contaminants from the blocks.  相似文献   

2.
Reef blocks made from stabilized oil ash were taken from the sea after five years in the ocean to examine the chemical behaviour of calcium. Experiments included (1) determination of the calcium leaching rate and a comparison with the rate for unexposed blocks to test the validity of a diffusion model for predicting long term (5 years) leaching rates, (2) determination of the effect of biological cover (shell) on the leaching rate, (3) determination of the leaching rate of the core of exposed reef blocks, (4) determination of the calcium content in 'ring areas' - regions of discoloration observed in sectioned exposed reef blocks, and (5) determination of the leachable fraction of the total calcium in exposed reef blocks. Results showed the presence of a pronounced calcium discontinuity zone located 3-7 cm from the outside surface of the reef blocks. Cumulated calcium release rates ranged from 2.81-3.14 μmol cm-2 day-1 for original unexposed reef blocks and the core of exposed (in the ocean for five years) blocks, respectively, to 0.47-0.50 μmol cm-2 day-1 for outside (facing sea water) surfaces of exposed reef blocks. Tank leaching studies also showed that the presence or absence of hard biological cover (shells) had little or no effect on the calcium release rate. the diffusion model normally used in modelling the chemical behaviour of calcium cannot be used to predict the long term (five years) leaching of calcium. the core of the exposed blocks released calcium at a rate similar to new, unexposed reef block material. Overall, it appears that the calcium discontinuity zone is probably responsible for restricting the release of calcium and hence the failure of the diffusion model.  相似文献   

3.
Abstract

Reef blocks made from stabilized oil ash were taken from the sea after five years in the ocean to examine the chemical behaviour of calcium. Experiments included (1) determination of the calcium leaching rate and a comparison with the rate for unexposed blocks to test the validity of a diffusion model for predicting long term (5 years) leaching rates, (2) determination of the effect of biological cover (shell) on the leaching rate, (3) determination of the leaching rate of the core of exposed reef blocks, (4) determination of the calcium content in ‘ring areas’ - regions of discoloration observed in sectioned exposed reef blocks, and (5) determination of the leachable fraction of the total calcium in exposed reef blocks. Results showed the presence of a pronounced calcium discontinuity zone located 3–7 cm from the outside surface of the reef blocks. Cumulated calcium release rates ranged from 2.81–3.14 μmol cm?2 day?1 for original unexposed reef blocks and the core of exposed (in the ocean for five years) blocks, respectively, to 0.47–0.50 μmol cm?2 day?1 for outside (facing sea water) surfaces of exposed reef blocks. Tank leaching studies also showed that the presence or absence of hard biological cover (shells) had little or no effect on the calcium release rate. the diffusion model normally used in modelling the chemical behaviour of calcium cannot be used to predict the long term (five years) leaching of calcium. the core of the exposed blocks released calcium at a rate similar to new, unexposed reef block material. Overall, it appears that the calcium discontinuity zone is probably responsible for restricting the release of calcium and hence the failure of the diffusion model.  相似文献   

4.
Box cores and surficial sediments collected from the shelf, slope and Okinawa Trough of the East China Sea were analyzed for loss on ignition, and concentration and speciation of Al, Fe, Mn, Pb, Cd, Cu and Zn. in general, concentrations of these metals are higher in the inner shelf and lower in the midshelf, but the highest LOI, Cd and Mn levels are found in the Okinawa Trough. Spatial distributions of these metals in surficial sediments indicate that the Yangtze River is the major source for materials deposited in the inner shelf. the results of a six-stage sequential leaching experiment indicate that the fluvial input includes natural (e.g., Al and Fe) and anthropogenic (e.g., Pb) materials. the depletion concentration of these metals in the midshelf sediments reflects the dominance (∼ 70%) of coarse, relict sand, while the enrichments in the inner shelf and the Okinawa Trough sediments are due to the fine grained, organic-rich sediments. the speciation of Mn in the sediments of the Okinawa Trough indicates that its distribution is diagentically or hydrothermally controlled.  相似文献   

5.
Box cores and surficial sediments collected from the shelf, slope and Okinawa Trough of the East China Sea were analyzed for loss on ignition, and concentration and speciation of Al, Fe, Mn, Pb, Cd, Cu and Zn. in general, concentrations of these metals are higher in the inner shelf and lower in the midshelf, but the highest LOI, Cd and Mn levels are found in the Okinawa Trough. Spatial distributions of these metals in surficial sediments indicate that the Yangtze River is the major source for materials deposited in the inner shelf. the results of a six-stage sequential leaching experiment indicate that the fluvial input includes natural (e.g., Al and Fe) and anthropogenic (e.g., Pb) materials. the depletion concentration of these metals in the midshelf sediments reflects the dominance (~ 70%) of coarse, relict sand, while the enrichments in the inner shelf and the Okinawa Trough sediments are due to the fine grained, organic-rich sediments. the speciation of Mn in the sediments of the Okinawa Trough indicates that its distribution is diagentically or hydrothermally controlled.  相似文献   

6.
Laboratory studies were conducted to determine leaching characteristics of waste-to-energy (WTE) residues in sea water to provide initial evaluation on the potential impact of WTE residues on the marine environment. Both loose and stabilized WTE residues were investigated for the leachability of lead (Pb) and cadmium (Cd) in sea water. Results of the study showed that loose WTE fly ash was very reactive in sea water; release of Pb and Cd occurred immediately (<0.5 hr) after the ash came in contact with sea water. Stabilization (treated with Portland cement and other additives), however, significantly reduced leaching of Cd and Pb. While ocean disposal of untreated WTE residues would not be advisable, utilization of stabilized WTE residues for beneficial uses should be investigated.  相似文献   

7.
根据2012年5月埒子口海域17个站位的环境监测资料,采用地统计学方法分析表层沉积物中7种重金属(As、Hg、Cu、Pb、Zn、Cr和Cd)的空间分布特征,利用潜在生态风险指数法进行重金属生态风险评价。结果表明,埒子口海域表层沉积物重金属含量均达GB 18668—2002《海洋沉积物质量》中规定的1类标准,质量总体较好。重金属空间分布趋势表现为西墅河口和灌河口附近海域重金属含量偏高,靠近外海一侧海域偏低,西北-东南向相关性较好;西墅河口和灌河口入海污染物是重金属的主要污染来源。重金属综合污染系数与潜在生态风险指数具有较好的相关性和一致性,总体处于低~中等水平。Cd既是主要的重金属污染元素,也是重要的生态风险贡献因子。生态风险高值区主要分布在西墅河口和灌河口附近海域,说明排放入海的污染物对海洋生态环境影响较大。  相似文献   

8.
The zinc, cadmium, copper and lead release from the uncontaminated and contaminated coastal sediments with aerated sea water was studied. the metals transfer to the dissolved forms was monitored during one-two months by differential pulse anodic voltammetry (DPASV). the sediments with different initial degree of contamination were sampled in the Peter the Great Bay, Sea of Japan around Vladivostok-the biggest city in Russian Far East. Sediment contamination by metals led to increased release to solution of zinc due to sulphide oxidation and cadmium on account of organic matter decomposition. the copper behaviour was complicated by strong binding with organic matter and enhancements of copper release can only be seen in sediment with a low organic matter content. Significant lead transfer to dissolved forms was not observed regardless of sediment contamination. the temperature affected the release of cadmium and copper through enhanced organic matter destruction. the dissolved metal fluxes from the sediment transformation are compared with metal fluxes towards bottom. Such comparisons show that second contamination by dissolved metals of the studied coastal environment may be important for cadmium only.  相似文献   

9.
• A high abundance of floating MPs was found in the southern South China Sea. • Transparent film and fiber were predominant in water and organisms, respectively. • 84.7% of floating MPs and 54.5% of MPs in vivo belonged to PP and PE. • Characteristics of MP in organisms were different from those of inshore ones. Surrounded by emerging markets with considerable plastic consumption, the South China Sea has been a focus area of microplastic research. A survey on the floating microplastics (>0.3 mm) and microplastics ingested by fish and mollusks was conducted around three remote islands here. Compared with the results from several previous studies, a high abundance of floating microplastics (with a median of 1.9 × 105 items/km2 or 0.7 items/m3) was observed, revealing another “hot spot” for microplastics. Polyolefin, especially polypropylene, was the main component. The diversity index and evenness index were calculated and evaluated based on the composition of microplastics. The characteristic peaks of Raman spectra concerning pigmented microplastics were provided. Transparent sheets/films were predominant in the water sample, which was quite different from a similar study in this sea area (8.9% for film), and only 16.4% of floating microplastics (>0.3 mm) were fibers/lines, implying that the main sources of floating microplastics (>0.3 mm) might be household/agricultural consumption activities. The transparent fiber/line was also dominant in organisms. It is suggested that the main sources of microplastics ingested by organisms might be both fabric fibers and fishing/aquaculture.  相似文献   

10.
水体作为环境污染因子的最终归宿,不仅容纳了越来越多的有毒物质,而且由于水体的立体性,水生生物极易受到多种因子的复合污染,易造成潜在的生态和健康风险。其中,重金属和持久性有机污染物因分布广、难降解且毒性效应复杂等特点,对水生生态易造成潜在危害而受到广泛的关注。环境污染往往是以混合物的形式联合存在,而联合毒性作用的相关研究较少。因此,本文围绕近年来典型重金属和全氟化合物的单一毒性,以及复合污染对水生动物的联合毒性作用进行了综述,现有的研究结果表明,复合污染对生物体存在联合毒性作用,可能表现为单一元素毒性作用、协同作用或拮抗作用,并对存在的问题和今后的关注重点进行了探讨,以便为未来的研究提供借鉴。  相似文献   

11.
将无锡城乡交错区河网分为城镇生活区水巷、工业区主河道、农业区主河道、农业区支流和鱼塘5种类型区.通过秋季(旱季)和夏季(雨季)2次采样,研究氮、磷和Cu、Zn、Pb、Cr、Cd在地表水和沉积物中的含量及其空间变化.结果表明:(1)城乡交错区地表水氮、磷来源于生活污染和工业污染的比例大于农田,同时具有来源分散、污染面广的特征.(2)由于城镇地表径流和工业活动影响,各类型区地表水重金属含量均有不同程度提高.但地表水重金属主要沿主河道迁移,旱季和雨季主河道重金属含量均大于农业区支流,而且随着与城镇距离增加,主河道沉积物重金属含量迅速降低,重金属污染影响范围较小.(3)与重金属相比,地表水氮、磷污染仍是太湖水网区主要的环境问题.但城镇及其周围河流沉积物中富集的重金属含量很高,其潜在环境风险不容忽视.  相似文献   

12.
基于CAPE技术公司的兔子复合克隆抗体的二恶英(PCDD/F)酶免疫分析试剂盒,建立了快速检测垃圾焚烧飞灰和烟气中PCDD/F毒性(TEQ值)的方法.试剂盒的最低检测限为3.3pg·tube-1(即3.3pgTEQ每EIA试管),线性检测范围为10~30pg·tube-1.样品经甲苯索氏抽提后过硅胶柱连接小碳柱净化处理,TCDD/F的回收率大约为50%,与原飞灰PCDD/F分布模式相比净化处理后样品中的TCDD/F含量明显降低.用净化处理后的飞灰溶液作标准溶液,绘制PCDD/F剂量-效应关系曲线,定量分析了2个飞灰样品和2个烟气样品的TEQ浓度,结果表明分析样品的TEQ实测值(HRGC/HRMS分析获得)与预测值(标准曲线计算值)的相对偏差(Rd)均小于15%,说明用该方法定量分析垃圾焚烧飞灰和烟气中PCDD/F毒性是可行的.  相似文献   

13.
A five-step sequential extraction technique was used to determine the chemical association of heavy metals (Pb, Zn, Cu and Cd), with major sedimentary phases (exchangeable, surface oxide and carbonate, Fe and Mn oxides, organic and residual metal ions), in samples from floodplain and recent flood sediments of the River Aire, West Yorkshire. Analysis indicates that metals Pb and Zn are primarily associated with the Fe and Mn oxides, Cu with the organic fraction and Cd with exchangeable and surface oxide and carbonate metal ions. Knowledge of the chemical speciation of heavy metals in river sediment, despite the procedure's inherent limitations, facilitates an understanding of their bioavailability, storage and remobilisation in floodplain and river channel environments.  相似文献   

14.
宝鸡城市街尘、土壤及河流沉积物重金属形态迁移特征   总被引:1,自引:0,他引:1  
在宝鸡城市街尘、土壤及河流沉积物基本理化性质和重金属元素含量分析的基础上,重点研究了重金属元素在街尘、土壤及河流沉积物中的赋存形态和迁移特征.结果表明:在街尘中Cu主要以可氧化态和残余态形式存在,Pb主要以可还原态和可氧化态形式存在,Zn和Cd主要以乙酸可提取态形式存在,Mn、Fe、Co、Ni和Cr主要以残余态形式存在...  相似文献   

15.
镍钴采选废石和尾矿中重金属的溶出释放规律对矿区的重金属污染防治具有重要意义。但目前,国内还没有对镍钴行业采选产生的尾矿和废石中重金属的溶出规律开展研究。本文以镍钴采选企业的尾矿和废石作为样本,开展了毒性浸出实验。研究了不同pH值、离子强度、温度等实验条件对重金属溶出的影响,探讨了镍钴采选过程中所产生的尾矿和废石中重金属的溶出特性和释放规律。实验结果表明,尾矿样品中Ni的浸出浓度为42.28 mg·L^-1,是最大允许排放浓度的8.86倍,为具有浸出毒性特征的危险废物;废石样品中重金属Ni和Cu的溶出浓度分别为4.72 mg·L^-1和26.2 mg·L^-1,超过最大允许排放浓度,属于第Ⅱ类一般工业固体废物。pH对样品中Ni、Cr、Pb、Co和As的溶出量影响较大,其中尾矿中Ni和Cu在pH较低的条件下,可达到44.28 mg·L^-1和53 mg·L^-1,远高于最大允许排放浓度,而Hg、Cd和Cu的溶出量随pH值的变化不大。除As以外,样品中大多数重金属的溶出质量浓度在酸性条件下比在中性条件下高,这表明在酸性环境条件下,这些重金属对周围生态环境的潜在风险更大。离子强度的变化对Cd和Co的溶出量的变化并不明显,而当离子强度变化时,Ni、Cr、Pb、Hg、Cu和As的溶出量可能达到最大,使周围环境的潜在生态风险增大。当温度达到35~40℃时,部分重金属如Co、Pb、Cd 等,溶出量将达到最大;当温度低于25℃时,除 Ni 以外,大部分重金属溶出量很低。而温度变化对重金属Cu、As、Cr和Hg的溶出量的影响不明显,波动范围较小,对周围生态环境产生的潜在生态风险较小。  相似文献   

16.
青岛城市污水厂污泥有机质、养分及重金属含量   总被引:1,自引:0,他引:1  
对青岛市4个典型城市污水厂脱水污泥中有机质、养分及重金属指标进行了调查研究,结果表明,所调查的青岛市4个典型城市污水厂污泥中的有机质平均含量为48.58%,总氮、总磷、总钾平均含量分别为36 437.76 mg/kg、12 590.13 mg/kg2、791.55 mg/kg;青岛市4个典型城市污水厂脱水污泥中的重金属...  相似文献   

17.
南京市土壤重金属污染调查评价   总被引:28,自引:0,他引:28  
在南京地区总共采集土样36个,以《土壤环境质量标准》GB15168-1995二级标准为评价标准,对南京市土壤重金属Pb、Zn、Cr、HB、Cu的污染状况作了初步评价。研究发现南京近郊重金属污染以汞和锌为主,江宁县附近为污染重区。污染原因有:工矿企业废物的排放;各类肥料和农药的施用;生活垃圾的农用。在评价的3种主要土地利用类型中污染比较严重的是受人为影响比较大的菜地和水田,说明人为影响是土壤重金属污染的主要原因。  相似文献   

18.
黄浦江水源地沉积物重金属潜在生态风险评价   总被引:1,自引:0,他引:1  
为了解黄浦江上游饮用水源地沉积物中重金属的污染特征,对黄浦江干流和主要支流15个采样点的Hg、Cd、Pb、Cu和Zn含量进行检测,并对其生态风险进行评价.相比环境背景中位值,在15个样品中5种重金属含量都存在一定比例的超标现象,其中,Cd和Hg的污染相对明显;相比背景最大值,仅有Cu和Cd含量超标.采用潜在生态风险指数法和污染负荷指数法进行评价,所得出的生态风险等级均为无污染~中等污染水平,急水港近苏沪交界处、淀峰大桥、大蒸港沪浙交界处、大蒸港泖洋河交汇处、园泄泾以及五厍东一号河交界处区域生态风险较高,Cd和Hg是研究区域生态风险的主导因子.值得注意的是,黄浦江支流大蒸港和园泄泾的生态风险整体高于黄浦江干流.总体而言,黄浦江上游水源地表层沉积物中重金属污染仍处于中等以下水平.  相似文献   

19.
Dissolved Cu, Fe and Ni were determined in sea water samples from 9 stations in the Ligurian Sea located along the two traverses Imperia-Capo Corso and Nice-Calvi and at depths between 0 and 200 m. The samples were preconcentrated from small volumes of sea water by complexation with ammonium pyrrolidine-dithiocarbammate (APDC), extraction with CCl4 and determination by AAS with electrothermal atomisation. The geographical distribution shows that in the central part of the inner traverse there is a maximum of Cu and Fe concentration; the vertical distribution shows no significant depletion of the dissolved elements in the epithalassa.

The results allow for a first approach to the more general problem of the distribution of the trace elements in the Ligurian Sea.  相似文献   

20.
北京市土壤和TSP中重金属分布特征及相关性研究   总被引:1,自引:0,他引:1  
城市土壤、大气作为城市生态系统重要组成部分,是城市居民赖以生存的基本物质环境,其重金属污染一直是研究的热点。土地利用方式不同,受到的人类活动影响程度不同,其土壤、大气重金属分布不同。以北京市4个功能区(工业区、交通区、居民区和公园区)为研究对象,通过采集0~20、20~40、40~60 cm的土壤和TSP样品,使用电热板消解和电感耦合等离子体发射光谱仪测定样品中7种重金属元素Cd、Cr、Cu、Mn、Ni、Pb、Zn的质量分数,分析土壤和TSP中重金属的空间分布特征及两者之间的相关关系,旨在正确认识人类活动对城市土壤、大气环境的影响,为北京市环境保护与治理提供理论依据。研究结果表明,(1)北京市土壤重金属Cd、Cr、Cu、Mn、Ni、Pb、Zn的平均质量分数分别为2.62、61.34、11.87、533.82、23.45、24.36、116.42 mg·kg-1。从单因子污染指数来看,Cd、Zn 的平均质量分数超过国家《土壤环境质量标准》一级标准限值,污染指数分别为13.1、1.16。(2)空间上,表层土壤重金属元素含量总体表现为工业区、居民区、交通区的含量高于相对清洁的公园区。垂直剖面上,工业区、居民区及交通区的重金属总体上表现出弱的表聚性,公园区土壤表现为很好的原始性。(3)比较TSP中重金属质量浓度最高值与最低值的比值,从大到小依次为:Ni(4.73)>Pb(3.26)>Mn (2.85)>Cd(2.59)>Cu(2.19)>Cr(1.83)>Zn(1.46)。(4)北京市土壤和大气重金属元素之间的相关性不强,说明大气干湿沉降未使北京市土壤重金属含量产生显著变化。  相似文献   

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