Metal binding capacity of northern European surface waters for Cd,Cu, and Pb     

John P. Giesy  Linda A. Briese 《Organic Geochemistry》1980,2(2):57-67

Total concentrations of and binding capacities for Cd, Cu, and Pb were measured in selected surface waters from northwestern Europe. Linear multiple regression predictive models explained 97, 93, and 96% of the observed variation in Cd, Cu and Pb binding capacities, respectively. The models constructed used (CO₂^3?) and (SO₂^2?) to predict Cd binding capacity, (OH^?) and (SO₄^2?) to predict Cu binding capacity and (OH^?), (CO₃^2?) and (SO₄^2?) to predict Pb binding capacity. Organic carbon was not significantly correlated with binding capacities for Cd, Cu, and Pb and was unimportant in explaining a significant amount of the variability in binding capacities for the metals of northern European surface waters. Thus, the effects of these organics on trace metal speciation can be ignored and predictive models of trace metal speciation constructed, using inorganic solubility equilibria only. Ratios of total Cd, Cu, and Pb concentrations to their respective binding capacities were much less than unity for all waters studied. Copper exhibited the greatest metal concentrations: binding capacity ratio in all waters investigated.  相似文献   

Determination of the extent of anthropogenic Pb migration through fractured sandstone using Pb isotope tracing     

《Applied Geochemistry》1997,12(1):75-81

The extent of vertical migration of anthropogenic Pb beneath a medieval smelting site in Derbyshire, U.K. has been estimated using the determination of total Pb concentrations and ²⁰⁶Pb/²⁰⁷Pb isotope ratio from samples taken down 6 m of drill core. Preliminary studies of total Pb concentrations established that the surface slag derived from the smelting contained up to 16% Pb and that the normal background levels in uncontaminated sandstone were 10±2 ppm. Sample analyses beneath the site revealed elevated Pb concentrations in fracture infill clays (270 ppm Pb) and sandstone (76–83 ppm Pb). Both are well above the background Pb concentration.Lead isotope analysis of the slag wastes, the underlying contaminated sandstone and fracture infill has shown that all 3 contain very similar isotope ratios for ²⁰⁶Pb/²⁰⁷Pb (1.1802–1.1820). However, matched control sandstone samples show that the background ²⁰⁶Pb/²⁰⁷Pb isotope ratio (1.1670 ± 0.003) is distinctly different. This would indicate that both the sandstone and fracture infill underlying the historical smelting site contain a substantial proportion of Pb that has been derived from the overlying contamination.The application of total Pb concentrations along the core and isotope analysis suggest that anthropogenically derived Pb from the smelting site (that was operated between 665 and 445 a BP) has migrated to a depth of 4.50 m. Assuming a uniform migration rate and a mean time of migration of 555 a, then the mean migration rate is estimated to be 8 ± 2 mm/a.The proportion of natural versus anthropogenic Pb in the samples has been estimated from small variations in the ²⁰⁶Pb/²⁰⁷Pb isotope ratio. If the slag is considered to contain 100% anthropogenic Pb and the uncontaminated sandstone considered to contain 100% natural Pb, the linear interpolation can be applied between the 2 end members of the isotope ratio. The use of this approach to the ²⁰⁶Pb/²⁰⁷Pb ratio measurements has shown that 88% of the Pb in the contaminated sandstone (i.e. 69 ppm from a mean total Pb concentration of 78.5 ppm) has been derived from the anthropogenic Pb at the surface. For the fracture infill sample taken at a depth of 4.50 m, and with a total Pb concentration of 270 ppm, the % of Pb that has been derived from the slag wastes is approximately 98% (equivalent to 265 ppm Pb). The remaining Pb in both these samples (9.4 and 5 ppm, respectively) is deduced to have originated from the natural background concentration of Pb in the sandstone.The closeness of these estimates to the measured background concentration, suggests that a simple two-source model of Pb contamination is valid for this site.  相似文献   

Uranium(VI) sorption to hematite in the presence of humic acid     

《Geochimica et cosmochimica acta》1999,63(19-20):2891-2901

A long-standing problem in aquatic geochemistry has been the incorporation of natural organic matter (NOM) into speciation models. The general effect of NOM on metal ion sorption by particles has been understood for some time, and significant progress has been made in elucidating some of the details of the role of NOM through the use of surrogate organic acids such as citric acid. However, a gap exists between the general observations that have been made of NOM behavior and the inclusion of NOM in surface chemical models for metal ion sorption. In this paper, we report on the results of a study on the sorption of U(VI) by hematite in the absence and presence of Suwannee river humic acid (HA) and over a range of other system conditions (e.g., pH, I). Essential HA characteristics (e.g., its acid/base, metal binding, and surface chemical properties) were “captured” by representing the HA as an assembly of monoprotic acids with assumed pK values and without explicit correction for electrostatic effects. The ternary system (hematite/HA/U(VI)) was simulated through the combination of the binary submodels (i.e., CO₃²⁻/hematite, U(VI)/HA, U(VI)/hematite, and HA/hematite) with model constants fixed at the values determined from simulations of the respective experimental systems. However, the “summed-binary” approach undersimulated experimental results, and the ternary system model required the postulation of two ternary surface (Type A) complexes composed of the uranyl ion, hematite surface sites, and the model ligands comprising the HA. Consideration of the HA in this manner permitted the simulation of HA effects on U(VI) sorption by hematite over a range of solution conditions using a general speciation model.  相似文献   

Competitive sorption of copper and lead at the oxide-water interface: Implications for surface site density     

《Geochimica et cosmochimica acta》1999,63(19-20):2929-2938

The competitive sorption of Cu(II) and Pb(II) to colloidal hematite was investigated as a function of pH and total metal concentration. Acid–base titrations of the hematite and single-metal sorption experiments for Cu and Pb at low to medium surface coverages were used to calibrate two surface complexation models, the triple layer model, and a 2-pK basic Stern model with ion-pair formation. The surface site density was systematically varied from 2 to 20 sites/nm². Three different metal surface complexes were considered: (1) an inner-sphere metal complex; (2) an outer-sphere metal complex; and (3) an outer-sphere complex of singly hydrolyzed metal cations. Both models provided excellent fits to acid–base titration and single-metal sorption data, regardless of the surface site density used. With increasing site density, ΔpK of the stability constants for protonation reactions increased and metal surface complexes decreased steadily. The calibrated models based on different site densities were used to predict competitive sorption effects between Cu and Pb and single-metal sorption at higher total metal concentrations. Precipitation of oversaturated solid phases was included in the calculations. Best predictions of competitive sorption effects were obtained with surface site densities between 5 and 10 sites/nm². The results demonstrate that surface site density is a key parameter if surface complexation models are exposed to more complex, multicomponent environments. We conclude that competitive metal sorption experiments can be used to obtain additional information about the relevant surface site density of oxide mineral surfaces.  相似文献   

Isotopic provenancing of Pb in Mitrovica,northern Kosovo: Source identification of chronic Pb enrichment in soils,house dust and scalp hair     

《Applied Geochemistry》2016

Mitrovica, northern Kosovo, is the site of some of the highest Pb concentrations reported in human populations; exemplified by Pb concentrations in scalp hair of up to 130 μg g⁻¹ and widely-publicized of Pb-related ill-health and mortality amongst internally displaced populations. High human Pb burdens are accompanied by elevated concentrations of potentially harmful elements (PHEs) in soils and house dust within the city, which has a long history of mining and metallurgy. In this study enrichment-levels for PHEs in soils are quantified and compared to environmental quality guidelines and a statistically-derived estimation of background concentration. In addition, Pb isotopes (²⁰⁷Pb/²⁰⁶Pb, ²⁰⁸Pb/²⁰⁶Pb) are used to characterise the isotopic signatures of potential point sources of Pb and a mixing model employed to quantify the contribution of sources to Pb present in soils, house dust, and the scalp hair of children and young people. Pb isotopic evidence suggests that Pb in surface soils and house-dust is predominantly sourced from historical deposition of Pb-containing aerosols from metal smelting, with lower contributions from wind-blown dispersal of metalliferous waste. Pb present in scalp hair is interpreted as the result of non-occupational exposure and the ingestion and/or inhalation of Pb-enriched surface soil and house dust. This study represents one of the very few instances where this type of geochemical tracing technique has been successfully applied to definitively identify the source of Pb present within biological samples. The results of this study are of particular relevance to environmental management and highlight the human health risk posed by the legacy of now inactive mining and metallurgy in addition to the challenge posed in mitigating the risk posed by diffuse soil pollution.  相似文献   

Anthropogenic Pb accumulation in forest soils from Lake Clair watershed: Duchesnay experimental forest (Québec, Canada)   总被引：1，自引：0，他引：1  

Sabary Omer Ndzangou  Marc Richer-LaFLche  Daniel Houle 《Applied Geochemistry》2006,21(12):2135-2147

Mineral soil horizons (Ae, Bhf1, Bhf2, Bf, BC and C) were carefully collected from two podzolic soil profiles in the Lake Clair watershed (Québec) in order to assess anthropogenic trace metal accumulation. Petrographic and selective analyses were performed to establish the soil mineralogy and properties. Furthermore, a complete sequential extraction procedure has been applied to help understanding the complex chemical speciation of Pb in forest soils. Chemical speciation of Pb showed a strong vertical gradient: 85% of this metal is mainly partitioned in refractory minerals in the C-horizon whereas in the upper Bhf1 and Ae-horizons, less than 50% of Pb is associated with this fraction. In the Ae-horizon, for example, 35%, 30% and 12% of total Pb, respectively, is associated with the exchangeable, labile organic matter and amorphous Fe-Mn oxides fractions. The distribution of Pb and Cr in the studied forest soils mainly reflects progressive contamination of the watershed by anthropogenic atmospheric sources. The anthropogenic source is indicated by elevated Cr and Pb concentrations in the topsoil (Bhf and Ae) horizons and by strong negative correlation between ²⁰⁶Pb/²⁰⁷Pb ratios and total Pb concentrations. According to these isotopic values, penetration of anthropogenic Pb does not exceed 10 cm in both soil profiles. Below this depth, both Pb concentrations and isotopic ratios remain nearly constant and similar to values observed in pre-anthropogenic sediments from Lake Clair. These values are interpreted as the natural geochemical backgrounds of the watershed. Based on that behaviour, calculated anthropogenic Pb net inputs amounted to between 1.24 and 1.8 g/m².  相似文献   

应用毒性淋溶提取法评价天津市某工业用地及周围农田土壤中重金属生态风险     

王静  吴宇峰  王斌  张磊  王鑫  赵一 《岩矿测试》2015,34(4):464-470

毒性淋溶提取法(TCLP)是美国法定的一种生态环境风险评价方法,通过提取土壤中的重金属有效态判断土壤重金属污染状况和评估污染区域生态风险。本文应用TCLP法提取天津市某工业园区内及周围农田土壤中的有效态Cu、Pb、Zn、Cd,采用电感耦合等离子体质谱法和原子吸收光谱法分别测定重金属全量和有效态,结合单项污染指数和内梅罗综合污染指数评价了重金属生态风险。结果表明:研究区Zn是首要污染物,主要来源于镀锌厂、金属制品厂和电镀厂,其次是Pb和Cu污染,Cd无污染;Pb、Zn可能具有同源性或伴生关系;大部分土壤处于安全水平,重金属污染率不到30%,但农田土壤出现了Zn的轻度污染。重金属全量是影响重金属有效态含量较大的因素,当Zn全量大于环境质量标准限值(300 mg/kg),Pb全量大于80mg/kg时,有效态Zn、Pb与其全量均呈正相关。因此,可以使用TCLP法将土壤重金属全量与有效态进行量化评价重金属生态风险。  相似文献   

新疆石河子城区道路尘土的铅污染和铅同位素示踪研究     

黄勇  高博  王健康  李强  郭太君 《岩矿测试》2013,32(4):632-637

城市道路尘土中重金属污染已成为当前重大的环境问题之一.本文对我国西部石河子市城区道路尘土的重金属污染进行评价,利用电感耦合等离子体质谱法测定铅的含量及铅同位素组成,采用地积累指数法评价铅的污染程度.结果显示,石河子市城区道路尘土中重金属铅的含量范围为19.36 ～ 84.63 mg/kg,平均含量为37.85 mg/kg,高于当地土壤背景值,但明显低于我国其他大中型城市,表明当前石河子市的环境质量已经受到人为活动的干扰;尘土中铅的地积累指数在-0.59～1.54之间,平均值为0.30,属于轻度污染水平.利用铅同位素示踪法识别铅污染的来源,206pb/207Pb比值的范围是1.159 ～ 1.182,208 pb/207 Pb比值的范围是2.391 ～2.457,均接近于煤炭和建筑材料的铅同位素比值,初步判断石河子道路尘土的铅污染主要受到煤炭燃烧和城市建设的影响.  相似文献   

The Influence of Salinity on the Uptake, Distribution, and Excretion of Metals by the Smooth Cordgrass, Spartina alterniflora (Loisel.), Grown in Sediment Contaminated by Multiple Metals     

Sarahfaye Mahon  Kevin R. Carman 《Estuaries and Coasts》2008,31(6):1089-1097

The effect of salinity on the concentration of metals in Spartina alterniflora tissues and excreted salts and the distribution of metals between these compartments was tested in a greenhouse experiment. S. alterniflora stems were planted in pots of dredge sediment that was amended with a suite of six metals (Cd, Cr, Cu, Ni, Pb, and Zn). The overlying water of individual pots was maintained at treatment salinities of 0, 15, or 30 practical salinity units. The proportion of total metal distributed to the tissues and excreted salt of S. alterniflora was not significantly influenced by salinity for any of the metals. The concentration of Pb in root and leaf tissues and in excreted salt was influenced by salinity, as was the concentration of Zn in root tissue and excreted salt. Contrary to expectations, the concentration of Pb and Zn in excreted salts decreased as salinity increased. Although the influence of salinity on the concentration of Pb and Zn in S. alterniflora tissue has not been previously reported, the influence of salinity on the tissue concentrations of Pb agrees with previous research on dicots.  相似文献   

Fingerprinting Marcellus Shale waste products from Pb isotope and trace metal perspectives     

《Applied Geochemistry》2015

Drill cuttings generated during unconventional natural gas extraction from the Marcellus Shale, Appalachian Basin, U.S.A., generally contain a very large component of organic-rich black shale because of extensive lateral drilling into this target unit. In this study, element concentrations and Pb isotope ratios obtained from leached drill cuttings spanning 600 m of stratigraphic section were used to assess the potential for short and long term environmental impacts from Marcellus Shale waste materials, in comparison with material from surrounding formations. Leachates of the units above, below and within the Marcellus Shale yielded Cl/Br ratios of 100–150, similar to produced water values. Leachates from oxidized and unoxidized drill cuttings from the Marcellus Shale contain distinct suites of elevated trace metal concentrations, including Cd, Cu, Mo, Ni, Sb, U, V and Zn. The most elevated Mo, Ni, Sb, U, and V concentrations are found in leachates from the lower portion of the Marcellus Shale, the section typically exploited for natural gas production. In addition, lower ²⁰⁷Pb/²⁰⁶Pb ratios within the lower Marcellus Shale (0.661–0.733) provide a distinctive fingerprint from formations above (0.822–0.846) and below (0.796–0.810), reflecting ²⁰⁶Pb produced as a result of in situ ²³⁸U decay within this organic rich black shale. Trace metal concentrations from the Marcellus Shale leachates are similar to total metal concentrations from other black shales. These metal concentrations can exceed screening levels recommended by the EPA, and thus have the potential to impact soil and water quality depending on cuttings disposal methods.  相似文献   

Similar Adsorption Parameters for Trace Metals with Different Aquatic Particles   总被引：1，自引：0，他引：1  

Beat Müller  Anja Duffek 《Aquatic Geochemistry》2001,7(2):107-126

Conditional surface binding constants and complexation capacities for Zn, Pb, Cd, and Cu were determined from surface titration experiments of heterogeneous natural aquatic particulate matter of different origin and composition. Metals and particles were evaluated in naturally occurring concentration ranges in river water.The adsorption of trace metals can be adequately described with a single conditional binding constant over a wide range of metal : particle ratios. Binding constants for aquatic particles at pH 8.0 are remarkably independent from particle composition and are specific for each metal: log K^ads _Zn = 8.39, log K^ads _Pb = 9.67, log K^ads _Cd = 8.61, log ^ads _Cu = 9.84. From competition experiments with Ca and Pb we extracted a sorption coefficient for Ca of log K^ads _Ca = 2.5 (pH 8.0). Maximum surface binding capacities for all metal ions were found for particles containing high fractions of Mn-oxides which are associated with large specific surface areas. Generally, we found sorption capacities to decrease in the sequence Cu Pb, Zn > Cd.The experiments suggest that the conditional surface binding constants and complexation capacities are applicable to model trace metal adsorption in the concentration ranges of natural waters under conditions similar to the experiments. Results also imply that the chemical nature of particle surface sites is rather uniform in the intermediate concentration range or that the array of binding sites averages out differences in sorption strength over the prevailing concentration range of metal ions, respectively.  相似文献   

Anthropogenic and lithogenic sources of lead in Lower Silesia (Southwest Poland): An isotope study of soils,basement rocks and anthropogenic materials     

R. Tyszka  A. Pietranik  J. Kierczak  V. Ettler  M. Mihaljevič  J. Weber 《Applied Geochemistry》2012

To discriminate possible anthropogenic and lithogenic sources of Pb in Lower Silesia (SW Poland), the Pb isotope composition was investigated in a spectrum of rocks and anthropogenic materials as well as within 10 soil profiles. Silicate rocks in Lower Silesia have ²⁰⁶Pb/²⁰⁷Pb ratios that vary from 1.17 for serpentinites to 1.38 for gneisses, and this variability is reflected in the isotope composition of the mineral soil horizons. The Pb isotope composition of coals, ores and anthropogenic materials (slags and fly ashes) is rather uniform, with ²⁰⁶Pb/²⁰⁷Pb ratios ranging from 1.17 to 1.18. Similar ratios were observed in ore and coal samples from Upper Silesia. The O soil horizons also have uniform ²⁰⁶Pb/²⁰⁷Pb ratios of 1.17–1.18 and the heterogeneity of the ²⁰⁶Pb/²⁰⁷Pb ratios increases with depth in the soil profiles. Five soils, with varying Pb concentrations, analysed far from contamination centres, show consistent, approximately 2-fold enrichment in Pb concentration from the C to A horizons, which is consistent with natural re-distribution of Pb within the profiles. The increase in the Pb concentration is accompanied by a decrease in ²⁰⁶Pb/²⁰⁷Pb ratios, also attributed to natural Pb isotope fractionation. Four soil profiles from industrial areas show variable enrichments in Pb concentrations and these are attributed to anthropogenic input from air-borne pollutants or even slag particles at smelting sites. The implication is that a lithogenic Pb source can deviate from the basement rock composition, and detailed isotope characteristics of the geological background and natural enrichments in soils are often needed to determine the lithogenic/anthropogenic proportions of Pb in soils.  相似文献   

Heavy metal abundances in the Kandy lake—An environmental case study from Sri Lanka     

C. B. Dissanayake  A. M. Rohana Bandara  S. V. R. Weerasooriya 《Environmental Geology》1987,10(2):81-88

The Kandy lake, situated in the heart of Sri Lanka's second largest city with a population of nearly 120,000, has been monitored to probe the extent of heavy metal pollution. Although the lake is a source of drinking water to the city, a large number of effluent canals drain into the lake carrying a continuous flow of industrial and domestic waste matter. A total of 66 surface water samples were analyzed for their Fe²⁺, total Fe, total V, SO ₄ ²⁻ , Cd²⁺, and Pb²⁺ contents. Pb and Cd were found in high concentrations averaging 150 μg/l and 77 μg/l, respectively, and exhibit a marked positive correlation with each other (r=+0.94). Vehicular emissions and industrial waste matter contribute largely to the Pb and Cd contents of the lake, the anthropogenic influence outweighing the contributions made by geological materials. All field observations and laboratory experiments indicate a tendency of the Kandy Lake towards eutrophicity.  相似文献   

Effect of different industrial activities on heavy metal concentrations and chemical distribution in topsoil and road dust     

M. Gabarrón  A. Faz  J. A. Acosta 《Environmental Earth Sciences》2017,76(3):129

The development of industrial activity in recent years has promoted the pollution in this environment causing health problems to workers and the neighbourhood nearby. In order to determine the influence of different industrial activities in metals concentration and behaviour in soil and road dust, samples from three different industrial areas (service industry; refinery, fertilizer and power industry; and tannery industry) and a natural area were collected. Physical–chemical properties, metal content (Pb, Zn, Cu, Cr, Co, Ni) and the chemical distribution of metals were carried out. Results show largest accumulation of metals in road dusts samples for all industrial areas, being Zn, Pb, Cr and Cu the metals with highest concentrations. Each industrial activity contributes differently to the concentration of metals in soil and dust, and the highest concentrations of Cr were found from tannery industries, while Pb and Zn showed the highest concentration from refinery and fertilizer industry. It has been showed that industrial activity has influence on the physicochemical properties of soil and road dust and on the bioavailability of all metals. Chemical partitioning indicates that Pb, Zn, Cu and Cr distribution in the different solid phases is affected by industrial activity, while Co and Ni distribution is not affected by the industrial activity.  相似文献   

Hydrological and geochemical controls governing the distribution of trace metals in a mine-impacted lake     

A. Martin  S. Calvert 《Environmental Geology》2003,43(4):408-418

Factors controlling the distribution of mining-derived Cu, Pb and Zn in the waters and bottom sediments of a large Andean lake (Lago Junin, Peru) have been assessed based on sample collections in May/June 1997 (dry season) and February/March 1998 (wet season). Relatively low levels of trace metals detected in surface waters of the lake during the dry season contrasted greatly with the high values observed during the wet period. Dry season concentrations of total Zn, Cu and Pb in the central lake basin averaged 41, 4.4 and 0.24 µg/L, respectively. In contrast, the respective wet season concentrations of total Zn, Cu and Pb in areas of the main basin ranged up to 387, 52 and 40 µg/L. The seasonal variability in metal concentrations largely reflects an increase in the concentration of particulate metal phases during the wet season. Such observations can be attributed to changes in sediment loadings associated with mining-derived river inputs and changes in lake circulation resulting from hydroelectric dam operations. Surface sediments are characterized by lake-wide enrichments of Zn, Cu and Pb, with maximum concentrations reaching as high as 5, 0.25 and 0.7 wt%, respectively. Estimated rates of authigenic metal accumulation are not sufficient to account for the elevated metal concentrations in the main basin of the lake, indicating that metal distributions are governed by the accumulation of metal-rich particulates. Variations in the spatial distributions of Zn, Cu and Pb are suggested to be a function of varying host phases and textural sorting.  相似文献   

Heavy metals in stream sediments: Error versus concentration     

R.T. Ottesen  B. Blviken  J. Ekremsaeter  T. Volden 《Journal of Geochemical Exploration》1983,19(1-3)

A regional geochemical mapping program in southern Norway carried out by the Geological Survey of Norway is based on sampling of stream sediments at road/stream intersections. At each site two individual subsamples have been taken. The subsamples were treated independently during the chemical analysis. This procedure enables an estimation of the reproducibility of the element concentration at each sample site. The paper gives results for the average relative total, sampling and laboratory errors at various levels of metal concentration using data for HNO₃ -soluble Mn, Pb and Cu as examples. For Mn and Pb the relative total error reaches a minimum near the median concentration and increases toward both the high and low concentrations. For Cu the relative total and laboratory errors decrease with increasing concentration throughout the whole concentration range, while the sampling error is fairly constant. The results suggest that the models which are commonly used for error determination in geochemical data, are too simple as far as relationships between error and concentration are concerned.  相似文献   

Biogeochemical evolution of trace elements in a pristine watershed in the Brazilian southeastern coastal region     

《Applied Geochemistry》2001,16(9-10):1139-1151

Establishing ‘reference sites’ is a difficult task and a critical factor in determining the baseline functioning of ecosystems. The information thus obtained on nutrient and contaminant background concentrations in turn subsidizes the remediation of impacted landscapes. This paper reports a study on metal (Cr, Cu, Pb, Zn, Mn, Fe and Al) and nutrient (C) distribution in sediments from Capivari River watershed (Praia do Sul Biological Reserve, Ilha Grande, Rio de Janeiro State, Brazil), an area where typical SE Brazilian coastal ecosystems are located. Contrary to what one would expect from the high rate at which these ecosystems have been deteriorating in recent decades, the study site is surprisingly well preserved. The present study was developed to assess variations in heavy metal concentrations in river basin sediments, to identify the geochemical carriers of these elements, and determine the influence of water quality and organic matter on their distribution. Results showed that heavy metal distribution has been influenced by the natural biogeochemical properties of those ecosystems found in an upland-to-lowland sequence in the watershed. Minimum and maximum total concentration were: 5 and 23 mg/kg for Cr; 4 and 29 mg/kg for Cu; 13 and 53 mg/kg for Pb; 24 and 142 mg/kg for Zn; 54 and 342 mg/kg for Mn; 0.8 and 7.2% for Fe; 0.5 and 4.9% for Al; 6.3 and 25% for C. The pH and E_H are the key-parameters in explaining total metal concentration decrease in the swamp area, where dissolution processes and losses through metal transport seem important. The most important geochemical carriers are Al in the basin’s “continental” stretch and Fe in the estuarine portion. The data also provide evidence showing that organic matter is the key-parameter in Cu concentration control in the sediments through burial and accumulation processes especially in the swamp area. Heavy metal concentrations in sediments from the study area are generally lower than those found in similar regional ecosystems. Surface enrichment in heavy metal concentrations in collected sediment cores was not observed. The authors therefore conclude that this site is suitable as a ‘reference site’ for studies on the biogeochemistry and ecotoxicology of SE Brazilian coastal ecosystems.  相似文献   

Kinetic of biogenic sulfide production for microbial consortia isolated from soils with different bioaccessible concentrations of lead     

I. Labastida-Núñez  I. Lázaro  L. B. Celis  E. Razo-Flores  R. Cruz  R. Briones-Gallardo 《International Journal of Environmental Science and Technology》2013,10(4):827-836

Different technologies have been implemented for the treatment of acid mine drainage. Among these are technologies such as geochemical barriers and sulfidogenic reactors, which use biogenic sulfide (produced by sulfate-reducing bacteria) for metallic stabilization. Because both processes involve microorganisms, it is important to have a clear understanding of the factors that influence their activity in different toxic environments. Given that microbial communities isolated from polluted sites could have a higher tolerance to toxic ions, two consortia with sulfate-reducing activity were isolated from different soils impacted by mining activities. These soils had different total (401 and 19,300 mg Pb kg^?1), mobile (54 and 1,415 mg Pb kg^?1) and bioaccessible (316 and 3,175 mg Pb kg^?1) concentrations of lead. The kinetics of biogenic sulfide production (BSP) for both consortia were monitored in a batch reactor after they were exposed to different initial lead concentrations. These lead concentrations were established based on the results of lead mobility tests. The estimated BSP rates and biomass concentrations of both consortia showed different responses to the presence of lead. Results highlighted that lead sulfide precipitation on microbial cell is a tolerance mechanism identified and this one is triggered for the lead bioaccessible concentrations threshold in soil. These results could be useful for the designing of processes based on sulfate reducing activity for the removal or stabilization of metal present in water or soil, respectively.  相似文献   

Removal of lead(II) from aqueous stream by hydrophilic modified kapok fiber using the Fenton reaction     

Dongfang Wang  Daeik Kim  Chul-Ho Shin  Yufeng Zhao  Joon-Seok Park  Moonhee Ryu 《Environmental Earth Sciences》2018,77(18):653

A hydrophilic kapok fiber was prepared by a chemical process of the Fenton reaction and used as an adsorbent to remove Pb(II) from aqueous solution. The effects of experimental parameters including pH, contact time, Pb(II) concentration, and coexisting heavy metals were estimated as well as evaluated. The optimum concentrations of FeSO₄ and H₂O₂ for the Fenton reaction-modified kapok fiber (FRKF) were 0.5 mol L^?1 and 1 mol L^?1, respectively. The adsorption kinetic models and isotherm equations of Langmuir and Freundlich were conducted to identify the most optimum adsorption rate and adsorption capacity of Pb(II) on FRKF. The FRKF displayed an excellent adsorption rate for Pb(II) in single metal solution with the maximum adsorption capacity of 94.41?±?7.56 mg g^?1 at pH 6.0. Moreover, the FRKE still maintained its adsorption advantage of Pb(II) in the mixed metal solution. The FRKF exhibited a considerable potential in removal of metal content in wastewater streams.  相似文献   

Sorption of metals on humic acid   总被引：1，自引：0，他引：1  

H. Kerndorff  M. Schnitzer 《Geochimica et cosmochimica acta》1980,44(11):1701-1708

The sorption on humic acid (HA) of metals from an aqueous solution containing Hg(II). Fe(III), Pb, Cu, Al, Ni, Cr(III), Cd, Zn, Co and Mn, was investigated with special emphasis on effects of pH, metal concentration and HA concentration. The sorption efficiency tended to increase with rise in pH, decrease in metal concentration and increase in HA concentration of the equilibrating solution. At pH 2.4. the order of sorption was: Hg? Fe? Pb? CuAl ? Ni ? CrZnCdCoMn. At pH 3.7. the order was: Hg and Fe were always most readily removed, while Co and Mn were sorbed least readily. There were indications of competition for active sites (CO₂H and phenolic OH groups) on the HA between the different metals. We were unable to find correlations between the affinities of the eleven metals to sorb on HA and their atomic weights, atomic numbers, valencies, and crystal and hydrated ionic radii. The sorption of the eleven metals on the HA could be described by the equation $\text{Y =}\text{100}\text{[1 + exp ? (A + BX)]}$, where Y = % metal removed by HA; X = mgHA; and A and B are empirical constants.  相似文献