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1.
Direct infiltration of roof runoff into the ground may pose a potential risk of soil and groundwater contamination. The performance of two different barrier materials for the retention of zinc from roof runoff of an eleven year old zinc roof was examined in a field study. As barrier materials geotextile and clinoptilolite were applied. Automatic samplers were used to take samples both at the inlet and at the outlet of the retention facility. Samples of twenty rain events were examined. Zinc was detected in the roof runoff in concentrations of up to 25 mg/L, and lead which originates from the tin‐solder was present in concentrations of up to 84 μg/L. Under most circumstances, a first flush could be observed for the analysed substances. No retention of heavy metals was observed, where only geotextile was used as a barrier material. The clinoptilolite filter was able to adsorb up to 97 % of zinc from the roof runoff.  相似文献   

2.
Installation of a permeable reactive barrier to intercept a phosphate (PO4) plume where it discharges to a pond provided an opportunity to develop and test methods for monitoring the barrier's performance in the shallow pond-bottom sediments. The barrier is composed of zero-valent-iron mixed with the native sediments to a 0.6-m depth over a 1100-m2 area. Permanent suction, diffusion, and seepage samplers were installed to monitor PO4 and other chemical species along vertical transects through the barrier and horizontal transects below and near the top of the barrier. Analysis of pore water sampled at about 3-cm vertical intervals by using multilevel diffusion and suction samplers indicated steep decreases in PO4 concentrations in ground water flowing upward through the barrier. Samples from vertically aligned pairs of horizontal multiport suction samplers also indicated substantial decreases in PO4 concentrations and lateral shifts in the plume's discharge area as a result of varying pond stage. Measurements from Lee-style seepage meters indicated substantially decreased PO4 concentrations in discharging ground water in the treated area; temporal trends in water flux were related to pond stage. The advantages and limitations of each sampling device are described. Preliminary analysis of the first 2 years of data indicates that the barrier reduced PO4 flux by as much as 95%.  相似文献   

3.
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：6，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   

4.
Treatment of nitrogen in landfill leachate has received considerable attention recently because of the relatively low levels at which some nitrogen species (i.e., NH3) can be toxic to aquatic life forms. This study reports on the results of a three-year, pilot-scale field trial demonstrating the use of infiltration bed and nitrate barrier technology to achieve nitrogen removal in landfill leachate. The infiltration bed comprises an unsaturated sand layer overlying a saturated layer of waste cellulose solids (sawdust), which acts as a carbon source for heterotrophic denitrification. When loaded at a rate of 1 to 3 cm/day, the infiltration bed was successful at lowering leachate inorganic nitrogen (NH4++ NO3-) levels averaging 24.8 mg/L N by 89%, including 96% in the third year of operation. The surface water discharge criteria for un-ionized ammonia (NH3) were met on all occasions in the treated leachate during the second and third years of operation. Nitrogen attenuation is presumed to occur by a two-step process in which leachate NH4+ is first oxidized to NO3- in the unsaturated sand layer and then is converted to nitrogen gas (N2) by denitrification occurring in the underlying sawdust layer. Mass balance calculations suggest that the sawdust layer has sufficient carbon to allow denitrification to proceed for long periods (1.0 to 30 years) without replenishment. Because this technology is simple to construct and is relatively maintenance free, it should be attractive for use at smaller landfills where the installation of conventional treatment plants may not be feasible.  相似文献   

5.
Two shallow translational slides occurred in blanket peat on Skerry Hill, Co. Antrim, in November 1991 at sites adjacent to slides activated c. 25 years ago. Heavy rainfall, degraded drainage ditches and slope morphology are considered to have been important factors contributing to peat instability. The failure planes are located close to the peat base, at the boundary between less compact fibrous peat above and more compact humified peat below. The preservation of large blocks and rafts of intact peat and the limited amount of liquefied peat in the debris tongues is thought to reflect the degree of peat humification. There is also some evidence to suggest that the peat was probably undersaturated at the time of failure and this may have assisted preservation of intact peat blocks. Tension cracks, resulting from either short-term desiccation or long-term slow mass movement, are thought to have facilitated the rapid transfer of heavy rain to the subsurface peat, causing high pore-water pressures and lubrication of the failure planes. Vegetation recolonization will probably follow a pattern similar to that observed on the adjacent earlier slides.  相似文献   

6.
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   

7.
Suspended sediment adsorbs pollutants from flowing water in rivers and deposits onto the bed. However, the pollutants accumulated in the river bed sediment may affect the bio-community through food chain for a long period of time. To study the problem the concentration of heavy metals （Cr, Cd, Hg, Cu, Fe, Zn, Pb and As） in water, sediment, and fish/invertebrate were investigated in the middle and lower reaches of the Yangtze River during 2006-2007. The concentrations of heavy metals were 100-10,000 times higher in the sediment than in the water. Benthic invertebrates had relatively high concentrations of heavy metals in their tissues due to their proximity to contaminated sediments. Benthic invertivore fish had moderately high concentrations of heavy metals whereas phytoplanktivore fish, such as the silver carp, accumulated the lowest concentration of heavy metals. The concentrations of Cu, Zn, and Fe were higher than Hg, Pb, Cd, Cr, and As in the tissue samples. The concentration of heavy metals was lower in the river sediments than in the lake sediments. Conversely, the concentration of heavy metals was higher in river water than in lake water. While a pollution event into a water body is often transitory, the effects of the pollutants may be long-lived due to their tendency to be absorbed in the sediments and then released into the food chain. The heavy metals were concentrated in the following order： bottom material 〉 demersal fish and benthic fauna 〉 middle-lower layer fish 〉 upper-middle layer fish 〉 water.  相似文献   

8.
An environmental survey has been undertaken on the Pacific coast of Canada to document natural background levels of a number of heavy metals, including arsenic, in various species of marine fish and invertebrates. The majority of fish studied from four different sampling locations near a proposed mine site, contained arsenic with levels ranging from less than 0.4 to 37.8 mg/kg (wet weight). Crabs were found to contain the highest level of arsenic of all marine organisms tested. Results indicate that arsenic accumulates in marine fish and invertebrates and may possibly be a micronutrient.  相似文献   

9.
Investigation on the Pollution Potential of Waterworks Sludges Several contaminated sludges from water treatment plants with known or estimated concentrations of trace elements were investigated for their leaching characteristics and long-term stability using standard and advanced test procedures. Potentially hazardous elements in the sludge are zinc, nickel, and arsenic with concentrations of up to 1.2 g/kg dry matter (mass). Preliminary sorption tests with synthetic sludge components like iron hydroxide, manganese oxide, silicate clay minerals, and chitine powder as a model organic component showed that Cu is associated with the organic phase wheras arsenic is predominantly bound to the iron oxide minerals. The recently suggested pHstat test procedure was used to assess the leaching characteristics of metals at typical pH values. This procedure was compared with the DEV-S4 test, the current standard test in Germany, consisting of a simple lixiviation of the solids with water, without pH control. The pHstat test yields results which are much better to interprete than those obtained by the DEV-S4 procedure. The iron and manganese sludges are well buffered against changes in pH and redox potential so that low pH values and/or reducing conditions can hardly occur. Thus, in deposited material a sudden leaching of heavy metals is unlikely and due to the presence of iron and manganese oxides the pentavalent arsenic is protected against conversion into the highly mobile trivalent form at neutral to low pH. Co-deposition with reducing organic matter and alkaline stabilisation material or waste (like fly ash) could influence the binding properties and should be strictly avoided.  相似文献   

10.
Eloctromigraiion offers a potential tool for remediating ground water contaminated with highly soluble components, such as Na+, Cl, NO3 and SO4−. A field experiment was designed to lest the efficacy of electromigration for preconcontrating dissolved SO42 in ground water associated with a fossil-fuel power plant. Two shallow wells, 25 feel apart (one 25 feel deep, the other 47 feet deep), were constructed in the upper portion of an unconfined alluvial aquifer. The wells were constructed with a double-wall design, with an outer casing of 4-inch PVC and an inner lube of 2-inch FVC; both were fully slotted (0.01 inch). Electrodes were constructed by wrapping the inner lulling with a 100-foot length of rare-earth metal oxide/copper wire. An electrical potential of 10.65 volts DC Was applied, and tests were run for periods of 12, 44, and 216 hours. Results showed large changes in the pH from the initial pH of ground water of about 7.5 to values of approximately 2 and 12 at the anode and cathode, respectively. Despite the fact that the test conditions were far from ideal, dissolved SO42-; was significantly concentrated at the anode. Over a period of approximately nine days, the concentration of SO42- at the anode reached what appeared to he a steady-state value of 2200 mg/L. compared lo the initial value in ground water of approximately 1150 mg/L. The results of this field lest should encourage further investigation of electromigration as a tool in the remediation of contaminated ground water.  相似文献   

11.
River water and sediment embody environmental characteristics that give valuable eco-environmental information.Due to rapid industrialization,the aquatic environment of any urban river can be seriously polluted by heavy metals（HMs）.The global concern is caused by heavy metal pollution because of its potential harm to aquatic ecosystems and human health.In the Bhairab River,Bangladesh,surface sediment concentrations of globally alarming toxic metals such as arsenic（As）,chromium（Cr）,cadmium（Cd）,an...  相似文献   

12.
In this paper, we determined the concentrations of antimony species (antimonite (Sb(III)), antimonate (Sb(V)) and dissolved inorganic antimony (DISb)) and arsenic, in Bohai Bay seawaters, as well as the relationships of the analytes with environmental factors such as seawater characteristics (e.g., suspended particulate material (SPM), salinity and total organic carbon (TOC)), heavy metals, nutrients and phytoplankton species, and evaluated the sources of arsenic and antimony. Dissolved arsenic and antimony concentrations in the surface waters were ranging spatially from 1.03 to 1.26 ng/ml and 0.386 to 1.075 ng/ml, with mean values of 1.18 and 0.562 ng/ml, respectively. Sb(V) as the prominent chemical species constituted about 89%. Regarding arsenic concentrations in the surface waters, there was a tendency for a small variation. However, antimony species concentrations were much variable than arsenic. The highest arsenic and antimony concentrations were found near the Haihe Estuary. These distribution patterns were controlled mainly by environmental factors, biological activities and sources. In this region, DISb and Sb(V) negatively correlated with salinity. Besides, arsenic and antimony correlated well with the nutrients, chlorophyll a and phytoplankton, implying that arsenic and antimony had been involved in biological cycling. In addition, according to our estimate, about 333.5×108 mg/year of arsenic and 454.2×108 mg/year of antimony reached Bohai Bay via rivers.  相似文献   

13.
An assessment of metal contamination in surface sediments of the Jiaozhou Bay, Qingdao, one of the rapidly developing coastal economic zones in China, is provided. Sediments were collected from 10 stations and a total of 15 heavy metals were analyzed. Concentrations of metals show significant variability and range from 210 to 620 ppm for Ti, 2.7 to 23 ppm for Ni, 4.2 to 28 ppm for Cu, 5.2 to 18 ppm for Pb, 12 to 58 ppm for Zn, 0.03 to 0.11 ppm for Cd, 5 to 51 ppm for Cr, 1.5 to 9.9 ppm for Co, 5.3 to 19 ppm for As, 12 to 32 ppm for Se, and 19 to 97 ppm for Sr. Based on concentration relationships and enrichment factor (EF) analyses, the results indicate that sediment grain size and organic matter played important roles in controlling the distribution of the heavy metals in surface sediments of the Jiaozhou Bay. The study shows that the sediment of the Jiaozhou Bay has been contaminated by heavy metals to various degrees, with prominent arsenic contributing the most to the contamination. The analysis suggests that the major sources of metal contamination in the Jiaozhou Bay are land‐based anthropogenic ones, such as discharge of industrial waste water and municipal sewage and run‐off. Notably, the elevated heavy metal concentrations of the Jiaozhou Bay sediments could have a significant impact on the bay's ecosystem. With the rapid economic development and urbanization around the Jiaozhou Bay, coastal management and pollution control should focus on these contaminant sources, as well as provide ongoing monitoring studies of heavy metal contamination within the bay.  相似文献   

14.
The main environmental features of the Gulf of Batabanó, Cuba, Caribbean, were investigated through the analyses of surface sediments collected at 23 sites. In order to highlight the potential threats affecting the sedimentary compartment of this area, samples were analysed for: granulometry, mineralogy, heavy metals concentration (As, Cd, Cu, Mn, Ni, Pb, Zn), organic carbon, total nitrogen and radionuclides. Findings were compared with published data and “grey” literature.Results showed: granulometric homogeneity and a widespread carbonatic condition all over the gulf, probably due to stable bathymetry and lack of terrigenous input (except for the La Coloma basin); a rather pristine environment for what concerns heavy metals pollution, except for La Coloma where a large arsenic input was recorded; very low levels of natural and artificial radioactivity; a relevant quantity of sedimentary organic matter, providing biota with useful substrate for feeding and enhancing the food-web development while indirectly supplying lobster fisheries. Combined data highlighted the impact of the Dique Sur in reducing terrigenous input in the coastal area.Future studies should focus on dating of sediment cores for identifying and quantifying the changes acting in the gulf and on investigating the origins of the large arsenic input to La Coloma.  相似文献   

15.
Upper North Grain (UNG) is a heavily eroding blanket peat catchment in the Peak District, southern Pennines, UK. Concentrations of lead in the near‐surface peat layer at UNG are in excess of 1000 mg kg−1. For peatland environments, these lead concentrations are some of the highest globally. High concentrations of industrially derived, atmospherically transported magnetic spherules are also stored in the near‐surface peat layer. Samples of suspended sediment taken during a storm event that occurred on 1 November 2002 at UNG, and of the potential catchment sources for suspended sediments, were analysed for lead content and the environmental magnetic properties of anhysteretic remanent magnetization (ARM) and saturation isothermal remanent magnetization (SIRM). At the beginning of the storm event, there is a peak in both suspended sediment and associated lead concentration. SIRM/ARM values for suspended sediment samples throughout the storm reveal that the initial ‘lead flush’ is associated with a specific sediment source, namely that of organic sediment eroded from the upper peat layer. Using the magnetic ‘fingerprinting’ approach to discrimination of sediment sources, this study reveals that erosion of the upper peat layer at UNG is releasing high concentrations of industrially derived lead (and, by inference, other toxic heavy metals associated with industrial particulates) into the fluvial systems of the southern Pennines. Climate‐change scenarios for the UK, involving higher summer temperatures and stormier winters, may result in an increased flux both of sediment‐associated and dissolved heavy metals from eroding peatland catchments in the southern Pennines, adversely affecting the quality of sediment and water entering reservoirs of the region. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

16.
Tomohiro  Toki  Toshitaka  Gamo  Urumu  Tsunogai 《Island Arc》2006,15(3):285-291
Abstract   We collected free-gas and in situ fluid samples up to a depth of 200.6 m from the Sagara oil field, central Japan (34°44'N, 138°15'E), during the Sagara Drilling Program (SDP) and measured the concentrations and stable carbon isotopic compositions of CH4 and C2H6 in the samples. A combination of the CH4/C2H6 ratios with the carbon isotope ratios of methane indicates that the hydrocarbon gases are predominantly of thermogenic origin at all depths. The isotope signature of hydrocarbon gases of δ13      < δ13     suggests that these gases in the Sagara oil field are not generated by polymerization, but by the decomposition of organic materials.  相似文献   

17.
Abstract The abundance of magnetic microspherules in a Triassic-Jurassic continuous sequence of alternating chert and shale beds in the Mino accretionary complex, central Japan, was measured systematically. Depending on time, the magnetic microspherules extracted from shale beds change in abundance considerably from the minimum 0.9ppm/cm3 at latest Triassic ( ca 208Ma) and the maximum 75ppm/cm3 at late Early Jurassic ( ca 187Ma); however, the abundance is always higher approximately 10–100 (average 70) times than those from adjacent chert bed at any stratigraphic horizon. Such systematic difference reveals the origin of radiolarian bedded chert as cyclic-rapid accumulation of biogenic SiO2 under extremely slow accumulative environments of shale with probable aeolian dust in origin. The accumulation data for individual shale and chert beds were obtained based on the microspherule abundance and radiolarian biostratigraphy, i.e., ca 0.018g/cm2Ka for lower Jurassic shale beds and ca 1.9g/cm2Ka for adjacent chert beds.
Duration time to make a chert-shale couplet corresponds to a dominantly 15–20Ka interval (average 23 Ka) in Upper Triassic bedded cherts with a low paleolatitude, whereas a 40–45 Ka interval (average 42 Ka) in Lower Jurassic ones which may been formed in higher latitude than Triassics before the final accretion to the Asian continental margin. Depending on paleolatitude, the cyclicity of 23 and 42 Ka may correspond to Milankovitch cycles which have been well documented in deep-sea sediments.  相似文献   

18.
典型沙漠绿洲城市表土磁性特征及环境指示意义   总被引：8，自引：0，他引：8       下载免费PDF全文
选取典型沙漠绿洲城市（乌海、石嘴山、银川）表土为研究对象,对其环境磁学性质、土壤质地与重金属含量分布进行系统研究.结果表明,乌海市和石嘴山市表土为典型砂土,银川市为砂壤土.三个城市表土样品均以较粗的MD-PSD颗粒的亚铁磁性矿物（磁铁矿）为主导,磁化率均值分别为152×10-8、104×10-8和117×10-8 m3·kg-1.乌海市表土磁性矿物含量和磁性颗粒大小都显著高于石嘴山和银川市.重金属（Cr、Cu、Pb、Zn、Fe）的污染负荷指数（PLI）均显示,三个城市表土均存在轻度污染特征.同时磁化率和污染负荷指数在非工业区表现出点状高值分布,在工业区表现为面状高值分布特征.乌海市表土磁参数与重金属的相关系数显著高于石嘴山和银川,表明磁参数对于污染来源单一地区的污染程度评估更具优势.尽管三个城市表土磁学性质存在较大差异,但其磁化率均随污染负荷指数的增加呈现相同程度的递增.磁化率可以作为宁夏平原地区表土重金属污染程度评估的统一有效的代用指标.  相似文献   

19.
A column bioleaching experiment was carried out to compare the effectiveness of the fungus Aspergillus fumigatus to bioleach arsenic (As) and heavy metals from the tailings using two different methods. In the first method, which is named as distribution method (DM), the fungus was distributed in the column by means of vertical and horizontal layers of coarse sand. In the other method, named as surface applied method (SAM), the fungus was cultivated on the surface of the tailings, which was covered with a few centimeters of coarse sand. Results showed that in the DM, oxalic acid production was stimulated and maximum removal of As, Fe, Mn, and Zn was 53, 51, 81, and 62%, respectively. However, Pb removal was low (8%), which might be due to the precipitation of Pb as its oxalates. On the other hand, the maximum removal of As, Fe, Mn, Pb, and Zn were 22, 28, 37, 64, and 34%, respectively, for the SAM. Results of the sequential extraction study showed that the DM was effective in removing the water soluble, exchangeable, carbonate, and Fe/Mn oxide fractions of As, Fe, Mn, and Zn. Our study suggested that A. fumigatus has a potential to be used in remediation of heavy metal contaminated sites. Distributing the fungus throughout the entire tailings columns improved the bioleaching of heavy metals by the fungus.  相似文献   

20.
湖泊沉积物的重金属污染防治一直是环境领域的热点问题.本研究采用氨基生物炭作为覆盖材料,利用梯度扩散薄膜技术(DGT),研究了上覆水不同pH及水流扰动条件下Cu(Ⅱ)、Pb(Ⅱ)在沉积物水界面间的原位释放特征,以及氨基生物炭对湖泊沉积物重金属污染的原位修复效果.研究结果表明,在0 r/min或100 r/min水动力条件下,可移动态重金属离子有不断由沉积物向其他介质扩散的趋势,1.81 kg/m 2的氨基生物炭覆盖强度可降低Cu(Ⅱ)、Pb(Ⅱ)释放通量达89%以上,有效减小了水环境中重金属的潜在生态风险.在pH=5的酸性及pH=9的碱性水环境中原位修复效果较差,水体中大量的H+或络合物均会削弱氨基生物炭对重金属离子的吸附,当上覆水在pH=7的中性条件时原位修复效果最佳.100 r/min水流扰动下的上覆水Cu(Ⅱ)、Pb(Ⅱ)含量在释放平衡时较0 r/min条件下高出0.036~0.096μg/mL,说明高强度的水流扰动易造成覆盖材料的扬起和浮动,导致覆盖材料与重金属发生解吸.  相似文献   

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