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1.
Removal of mercury from mercury-contaminated sediments using a combined method of chemical leaching and volatilization of mercury by bacteria 总被引:2,自引:0,他引:2
A method for the removal of mercury sulfide frommercury-contaminated sediments was developed, whichconsists of chemical leaching and volatilization ofmercury by bacteria. More than 85% of the mercury insediment containing 0.11–37.4 mg/kg of mercury wasefficiently extracted with 3 M HCl and 74 mMFeCl3. Subsequent volatilization by bacteriaresulted in the removal of 62.9–75.1% of mercury frommercury-contaminated Minamata Bay sediments. Methylmercury was also eliminated from soil at a highefficiency. Thus, this combined method of chemicaland microbial treatments could be used for efficientremoval of both organic and inorganic mercurials fromnatural sediments. 相似文献
2.
三江平原典型湿地植物中汞的分布与库存量 总被引:14,自引:0,他引:14
分析了三江平原典型植物中的总Hg浓度.结果表明,各种植物中总Hg浓度差别较大,苔藓>藻类>苔草>禾草>灌木;干湿环境是影响总Hg浓度的重要因素;湿地植物总Hg浓度高于水稻和玉米等农作物.较高的土壤总Hg浓度是近地面大气中Hg的重要来源,间接地影响到植物中Hg的浓度.植物各构件中总Hg浓度具有立枯>根>叶>茎的特点.在植物整个生长季总Hg浓度先增加后减少.估算了三江平原湿地植物Hg的库存量.小叶章湿地植物地上部分库存量为24.9μg·m^-2;毛果苔草湿地植物地上部分库存量为35.8μg·m^-2,高于加拿大实验湖泊湿地. 相似文献
3.
Jean-François Ouellet Marc Lucotte Roman Teisserenc Serge Paquet René Canuel 《Biogeochemistry》2009,94(2):123-140
This study presents the role of specific terrigenous organic compounds as important vectors of mercury (Hg) transported from
watersheds to lakes of the Canadian boreal forest. In order to differentiate the autochthonous from the allochthonous organic
matter (OM), lignin derived biomarker signatures [Lambda, S/V, C/V, P/(V + S), 3,5-Bd/V and (Ad/Al)v] were used. Since lignin
is exclusively produced by terrigenous plants, this approach can give a non equivocal picture of the watershed inputs to the
lakes. Moreover, it allows a characterization of the source of OM and its state of degradation. The water column of six lakes
from the Canadian Shield was sampled monthly between June and September 2005. Lake total dissolved Hg concentrations and Lambda
were positively correlated, meaning that Hg and ligneous inputs are linked (dissolved OM r
2 = 0.62, p < 0.0001; particulate OM r
2 = 0.76, p < 0.0001). Ratios of P/(V + S) and 3,5-Bd/V from both dissolved OM and particulate OM of the water column suggest an inverse
relationship between the progressive state of pedogenesis and maturation of the OM in soil before entering the lake, and the
Hg concentrations in the water column. No relation was found between Hg levels in the lakes and the watershed flora composition—angiosperm
versus gymnosperm or woody versus non-woody compounds. This study has significant implications for watershed management of
ecosystems since limiting fresh terrestrial OM inputs should reduce Hg inputs to the aquatic systems. This is particularly
the case for large-scale land-use impacts, such as deforestation, agriculture and urbanization, associated to large quantities
of soil OM being transferred to aquatic systems. 相似文献
4.
Andrés Navarro 《Reviews in Environmental Science and Biotechnology》2008,7(4):287-306
The speciation of mercury—including most phase minerals, secondary phases, gaseous and aqueous species—is very important for
evaluating the environmental impact and mobilization of this contaminant. Mining activities produce mercury mine waste, which
includes several types of material (mainly mine waste and calcines) with varying mercury content and speciation depending
on the ore deposit and processing technology. The main phase minerals are cinnabar, metacinnabar, metallic Hg0, corderoite, livingstonite, calomel and schuetteite. The aqueous mobilization of mercury is controlled by complex formation,
pH-Eh conditions, the primary phase mineral of mercury, and organic-matter and iron oxyhydroxide content. The possibility
of colloidal transport of mercury from mine waste is influenced by the atmospheric emission of metallic Hg0 and the leaching of waste by episodic high-intensity precipitations. In these climatic conditions, mercury can be mobilized
to pore water, surface water or groundwater by the dissolution of metallic Hg0 and cinnabar in acidic conditions, and by the colloidal transport. The presence of Hg-soluble phases (chlorides and oxychlorides)
may enhance the mobilization of mercury. In the semi-arid conditions of the Valle del Azogue (SE Spain) the atmospheric emissions
of the Hg0 present in calcines and mine waste may be significant and the dissolution of Hg0 and metal-sulfate salts during episodic runoff events may explain the mobilization of Hg, Fe, Pb, Zn and other heavy metals. 相似文献
5.
Mercury inputs and outputs at a small lake in northern Minnesota 总被引:1,自引:0,他引:1
Storages and cycling of total mercury (HgT), methylmercury (MeHg), and Hg0 are described for Spring Lake, a small bog lake in the Marcell Experimental Forest in north-central Minnesota. We quantified
photoredox transformations, MeHg photolysis, burial to the sediments, and internal and external loadings of HgT and MeHg. Atmospheric deposition was the main input of HgT; MeHg was supplied by a combination of atmospheric, near-shore wetland, and biotic (methylation) sources. HgT outputs were dominated by burial (67%), and Hg0 evasion accounted for 26% of HgT outputs. The watershed of Spring Lake is small (3.7× lake surface area), and accordingly, bog and upland runoff were minor
contributors to both HgT and MeHg inputs. Wet deposition was ∼9% of total MeHg input, and other external inputs (runoff, sediment porewater) provided
only an additional 7%, indicating that internal production of MeHg was occurring in the lake. Photolysis of MeHg, measured
in the field and laboratory, removed ∼3× the lake mass of MeHg (20 mg) annually, and was the dominant sink for MeHg. Residence
times of MeHg and HgT in the lake were 48 and 61 days, respectively, during the open-water season, compared with only 8 days for the residence
time of MeHg on settling particles (seston). Photoreduction of Hg2+ to Hg0 was greater than the reverse reaction (Hg0 photooxidation), and the residence time of Hg0 in the photic zone was short (hours). Data from this study show active cycling of all the measured species of mercury (HgT, MeHg, and Hg0) and the importance of MeHg photolysis and photo-redox processes. 相似文献
6.
Development of an automated micrometeorological method for measuring the emission of mercury vapor from wetland vegetation 总被引:2,自引:0,他引:2
The ability of green plants to act as conduits to enhance the transport ofHg from soils to the atmosphere is now established, but the data base isseverely limited. The potential role of this process in mobilizing Hg inglobal and regional cycles makes it imperative that automated methods bedeveloped to increase our capability to measure and understand the processin a variety of ecosystems. We previously published a tower-basedmicrometeorological gradient method for measuring gas-phase Hg°fluxes in terrestrial systems based on the Modified Bowen ratio (MBR)approach. The method relied on demanding and time-consuming manualsampling of Hg gradients. Automated Hg sampling methods now exist, andwe describe here applications of the Tekran Hg analyzer to automatednear-real-time measurements of Hg gradients over wetland vegetation. Weuse these data with MBR to compute fluxes of Hg from those of othertrace gases. From 1996 to 1998 we sampled Hg fluxes over emergentmacrophytes in the Florida Everglades, beginning with manual methods, butlater deploying automated methods for most of the study to collect morethan 500 30-min fluxes over 2 y. The limitations of the manual methodresulted in considerable uncertainly in our earlier observations, even to theextent that we initially doubted that vegetation emissions were real. However, the automated method allowed us to quantify the actualdevelopment of Hg emission gradients over wetland vegetation. Followingsunrise Hg fluxes show diel patterns similar to those of CO2 andH2O, providing information on the possible mechanisms of Hgemission. Our data suggest mean daytime emission rates of Hg over thesewetlands on the order of 30 ng m-2 h-1. Fluxes wereinfluenced by temperature, solar radiation, and atmospheric turbulence. There exists a significant biotic re-emission of Hg° from the oceans,and our data provide the first direct evidence of a similar process insubtropical wetlands. 相似文献
7.
Héctor Daniel García-Mercado Georgina Fernández-Villagómez Marco Antonio Garzón-Zúñiga María del Carmen Durán-Domínguez-de-Bazúa 《International journal of phytoremediation》2019,21(12):1170-1178
AbstractMercury has been extracted in Queretaro, Mexico since the 1960s. The mining wastes were open-air disposal and these mercury wastes have polluted the zone. The aim of this research was to evaluate mercury's fate in lab scale terrestrial reactors considering the following mercury species: soluble, interchangeable, strongly bound, organic, and residual ones. Soils were sampled in two former mines of Pinal de Amoles, Queretaro, Mexico (N 20° 58′ to 21° 21′ and West 99° 26′ to 99° 43′) with initial mercury concentrations were 424?±?29 and 433?±?12?mg?kg?1 for “La Lorena” and “San Jose” former mines, respectively. Two vegetal species Polypogon monspeliensis and Cyperus odoratus were used and 20 reactors were constructed for the lab process. Total mercury was removed to 49–79% from both soils. Mercury elemental, exchangeable, and organic species had the most removal or exchange in the process. Metal uptake, by the plants, was of 5–6% for P. monspeliensis and 5–15% for C. odoratus. Also, mercury fate was estimated to the atmosphere to be 3.3–4.5?mg m?2 h?1 for both soils. 相似文献
8.
9.
Selenium is known to form complexes with heavy metals in the blood and thus increase the retention time of the metals in several organs, especially in the reticulo-endothelial system. Selenium may similarly cause retention of mercury in the lung after metallic mercury (Hg0) inhalation. This study, comparing the effects of tellurium with those of selenium (both in group '6b' of the periodical system), showed that Te(IV) was as effective as Se(IV) and Se(VI) (all given in a dose of 10 mumol/kg body wt.) in retaining inhaled 203Hg0 (1.5 mumol/kg body wt.) in the lung (presumably 203Hg2+ after oxidation). Te(VI) had to be given in a dose of 100 mumol/kg body wt to produce the same effect. As in the lung, also in other organs tellurium caused a dose-dependent increase in mercury retention. At a dose level of 10 mumol Te(IV) per kg body wt. the mercury retention ratios (treated/control) were 140 for the lung and 8.6 for the whole body. The corresponding figures for Te(VI) (10, 30 and 100 mumol/kg body wt.) were 10, 73 and 120 and 3.7, 3.9 and 4.3, respectively. Retention of i.v. injected 203HgCl2 was increased by pre-administration of tellurium, again in a dose-dependent manner and Te(IV) being 3-10 times more effective than Te(VI). The kidney and the spleen were the dominant organs, as is the case after Se pretreatment. Anions of other elements, arsenite, arsenate, chromate, molybdate and wolframate (30 mumol/kg body wt.), did not affect the retention of 203Hg in lung or any other organ, or in the whole body after inhalation of 203Hg0. It is suggested that Te(IV) may easily be reduced to Te2- (in analogy with selenium) which may complex with Hg2+. The liability for Te(VI) to be reduced to Te2- appears to be approx. 10 times lower. 相似文献
10.
The purpose of this study was to remove cadmium (Cd) and mercury (Hg) from non-point source wastewater by a hybrid bioreactor consisting of two different processes (anaerobic–anoxic–aerobic and photoautotrophic). The results showed that the bioreactor could concurrently culture heterotrophic and autotrophic microorganisms, and removed Cd and Hg from the wastewater successfully. The average removal efficiencies were 79% and 66%, respectively for Cd and Hg. The relationship between Cd removal rate and biofilm mass was observed to be significant (p < 0.05) during different seasons. The Hg removal was mainly due to the bioaccumulation in macrophytes via a photoautotrophic process. Due to the increase of the bacterial diversity under the rejuvenated conditions modulated by the hybrid bioreactor, the growth conditions of the native bacterial habitat were improved. The results demonstrate that the environmentally benign, easily-deployed, sludge free and cost-effective hybrid bioreactor can efficiently remove Cd and Hg from non-point source wastewater. 相似文献
11.
Mercury (Hg) and its compounds are much concerned for their high toxicity and wide presence in the environment. Since the toxicity of Hg is species dependent, various methods have been developed for the speciation analysis of Hg. This review focus on the determination and speciation analysis of Hg chemical species in water, sediment, and soil samples. Recent developments on sample pre-treatment and extraction/pre-concentration, separation, and quantification of Hg chemical species, and associated analytical challenges have been reviewed and briefly discussed based on recent reports. 相似文献
12.
This paper investigates the relationship between nutrients, chlorophyll a and physical variables in the upper Saronikos Gulf, an oligotrophic marine environment south of the Greater Athens Metropolitan Area. Phosphate, silicate, ammonia, nitrite, nitrate, temperature, salinity and dissolved oxygen were determined at eight stations on 9 occasions during summer 1982. A thermocline led to the stratification of the water column and the pycnocline was related to the thermocline. The values of oxygen were more or less normal. The Eutrophication of the seawater in the vicinity of the sewage outfall was demonstrated by surface levels of chlorophyll a being forty to two hundred times above background. This parameter provides evidence for a high phytoplankton standing stock. However, there were no appreciable differences between the nutrients in the outfall area and those in the background. This suggests rapid uptake of nutrients and/or effective dispersal from the outfall. 相似文献
13.
Phosphorus release from sediments in a treatment wetland: Contrast between DET and EPC0 methodologies 总被引:2,自引:0,他引:2
Elizabeth J. Palmer-Felgate Michael J. BowesCharlie Stratford Colin NealSally MacKenzie 《Ecological Engineering》2011,37(6):826-832
Wetlands are capable of reducing nutrient loadings to receiving water bodies, and hence many artificial wetlands have been constructed for wastewater nutrient removal. In this study, diffusive equilibrium in thin films (DETs) and equilibrium phosphorus concentration (EPC0) analysis were used to examine the role of sediment as a nutrient source or sink in a constructed treatment wetland in summer. The effect of dredging on sediment-water nutrient exchange was also studied. Soluble reactive phosphorus (SRP), ammonium (NH4+) and sulphate (SO42−) concentration profiles were measured by DET across the sediment-water interface (SWI) in both a settling pond and iris reed bed within the wetland. The SRP concentrations in the sediment pore-waters of the settling pond were extremely high (up to 29,500 μg l−1) near the SWI. This is over an order of magnitude higher than the levels found in the water column, which in turn are over an order of magnitude higher than environmental levels proposed to limit eutrophication in rivers. The profiles demonstrated an average net release of SRP and NH4+ from the settling pond sediment to the overlying water of 58 mg m−2 d−1 (±32 mg m−2 d−1 (1 sd)) and 16 mg m−2 d−1 (±25 mg m−2 d−1 (1 sd)), respectively. The DET SO42− concentration profiles revealed that the sediment was anoxic within 2 cm of the SWI. Dredging of the reed bed made no significant difference to the P release characteristics across the SWI. The EPC0s were much lower than the SRP concentration of the overlying water, indicating that the sediment had the potential to act as a phosphate sink. The apparent contradiction of the DET and EPC0 results is attributed to the fact that DET measurements are made in situ, where as EPC0 measurements are ex situ. These results show that substantial releases of P can occur from wetland sediments, and also highlight the need for caution when interpreting ex situ EPC0 analytical results. 相似文献
14.
Jan DickoppAuthor Vitae Marian KazdaAuthor VitaeHana ?í?kováAuthor Vitae 《Ecological Engineering》2011,37(11):1647-1653
Waterlogged soils are a challenging environment for plants due to anoxic conditions and enrichment of phytotoxic substances in the rhizosphere. High contents of organic matter in the substrate as present in constructed wetlands (CW) may amplify these effects. The influence of substrate organic matter on the rhizome aeration of Phragmites australis (common reed) was investigated in a CW for sewage treatment on two sites with different organic concentrations: (a) inflow part of the bed with a high organic charge (high-organic site) and (b) outflow zone of the bed with a lower organic charge (low-organic site). Several diurnal oxygen (O2) courses were recorded inside the rhizomes using micro-optodes. Maximum O2 percentages in the rhizomes were generally the same at both sites, but minimum O2 values were lower in the low-organic site than in the high-organic site, leading to higher amplitudes at the low-organic site. The results suggest that oxygen release from the roots is hampered under high-organic compared to low-organic conditions. This observation might be explained by changes in gas conductivity of the roots, but also by alterations in microbial oxygen demand, under different organic burden. 相似文献
15.
Mercury speciation in natural waters: Measurement of dissolved gaseous mercury with a field analyzer 总被引:1,自引:0,他引:1
Mercury evasion from water is commonly modeled using measurements of dissolved gaseous mercury (DGM). We developed a method using a recently available automated field-ready mercury vapor analyzer to rapidly measure the concentrations of DGM in surface waters. We summarize here results of laboratory tests of the method, field intercomparisons with a manual method, and selected data from recent sampling campaigns in Florida and Michigan. The method uses the 1.5 lpm flow of a Tekran® Model 2537A mercury analyzer to purge and analyze discrete water samples, generating near real time (5-min) data on DGM in samples and blanks. Application of the Tekran allowed for detailed analysis of DGM removal kinetics and short-term diel studies characterizing the influence of sunlight and precipitation on DGM production in surface waters. Gas removal kinetics for dozens of samples indicates a first-order rate constant, and supports a 20-min. purge time for surface water samples from Florida (40-min for Michigan samples). Blanks are measured during a second such purge. Our results indicate that DGMs determined by both automated and manual methods are generally comparable, and that DGM in Florida samples is unstable during storage (loss rate constant 0.1--0.2 h-1), probably due to oxidation. This suggests that rapid in-field analysis is preferred to storage with delayed analysis. Our data indicate that DGM at the Florida site is influenced by inputs of reactive Hg in rainwater, and by production of surface DGM during photoreduction of oxidized Hg in the water column. 相似文献
16.
Although an understanding of the quantity and quality of sedimentary organic matter (SOM) pools is necessary to design sound environmental management strategies for lacustrine systems, the characterization of organic matter sources and the assessment of their relative contributions to eutrophic and inland lake sediments remain insufficient. In this study, the contribution of potential organic matter sources to sediments in shallow and hypereutrophic lake Taihu, China was assessed on the molecular level using source-specific fatty acid biomarkers. The results indicated that SOM was composed mainly of terrestrial plants with a maximal contribution of 45.3 ± 2.4% to the total organic carbon, which accounted for approximately 66% among the determined organic matter sources. Evidence suggests the terrestrial plants remained in a fresh state in surface sediments: the correlation (R2 = 0.62, p < 0.05) between bacterial and terrestrial plant carbon was strong. On the other hand, aquatic plant and bacterial carbon contributed 5–15% to the total organic carbon, which was followed by the faint contribution (<5% of total organic carbon) of algae-derived organic carbon including cyanobacteria, diatoms, and dinoflagellates. The results provided details of the contributions of SOM sources, illustrating the usefulness of fatty acid biomarkers in discriminating organic matter sources within lake environments. Although organic matter sources of sediments varied in spatial and temporal patterns, the strong correlation between terrestrial plant and total organic carbon (R2 = 0.60, p < 0.05) indicates that terrestrial plants were the dominant source in lake sediments. 相似文献
17.
泉州湾红树林湿地沉积物中汞分布及形态特征 总被引:1,自引:0,他引:1
采集了泉州湾红树林湿地表层沉积物样品,测定了沉积物中不同形态汞的含量,研究了汞的分布特征、赋存形态及其生物有效性.泉州湾红树林湿地表层沉积物中总汞含量范围0.03~0.22 mg·kg-1,除14#采样点外,其余各采样点均符合海洋沉积物质量(GB 18668-2002) Ⅰ类标准;沉积物中不同形态汞占总汞的比例为可氧化态(84.0%)>残渣态(14.0%)>可还原态(1.8%)>弱酸溶态(0.2%);沉积物中汞的生物有效性较高,对红树林生态系统存在一定的潜在危害. 相似文献
18.
Fluxes of mercury to lake sediments in central and northern Canada inferred from dated sediment cores 总被引:10,自引:0,他引:10
W.L. Lockhart P. Wilkinson B.N. Billeck R.A. Danell R.V. Hunt G.J. Brunskill J. Delaronde V. St. Louis 《Biogeochemistry》1998,40(2-3):163-173
Sediment cores were collected from lakes in central and northern Canada and from Hudson Bay to compare current and historic net depositions of mercury. Cores from most locations were enriched in mercury in the upper layers deposited recently relative to deeper, historic layers. The lakes with the greatest enrichments in mercury were located in central/southern Canada. This enrichment was interpreted as being of anthropogenic origin. Mercury inputs at the Experimental Lakes Area (ELA) in northwestern Ontario inferred from a core profile agreed well with inputs calculated independently from precipitation and runoff data. Anthropogenic inputs of mercury to northwestern Ontario were calculated to be about 9 µg m-2 y-1. Considering all the locations over the geographic range, the core profiles infer that fluxes of mercury have increased on average by about 2 fold over the past half century. This is consistent with results from other sites in North America and Europe. 相似文献
19.
Effect of urban sewage treatment on total and methyl mercury concentrations in effluents 总被引:1,自引:0,他引:1
The purpose of this study was to investigate the effect of sewage treatment on total mercury (THg) and methylmercury (MeHg) concentrations in domestic effluents and the contribution of urban sewage treatment facilities to THg and MeHg in rivers. We determined the concentrations of THg and MeHg in unfiltered samples of untreated and treated domestic sewage from the three treatment facilities and receiving river water within the City of Winnipeg. The concentrations of THg in the Red and Assiniboine rivers ranged from 3–31 ng/L. THg was related positively to suspended sediment concentrations in the rivers. The concentrations of MeHg in these rivers were usually 0.2–0.3 ng/L. THg concentrations in raw sewage varied widely, from 2–150 ng/L. Treatment removed an average of 88% of this mercury. MeHg concentrations in raw sewage were 0.5–4.3 ng/L, however, after treatment at two treatment facilities, MeHg was greatly reduced, usually to 0.1–0.4 ng/L. Most treated sewage, therefore, had MeHg concentrations that were similar to levels in the receiving rivers and the effect of discharged effluent was usually a change of about 2% or less on concentrations in the rivers. However, one of the facilities (the West End plant) was discharging higher concentrations of MeHg, up to 2 ng/L, causing calculated increases of up to 11% in the concentration of MeHg in the Assiniboine River. 相似文献
20.
Rhizosphere bacteria enhance the accumulation of selenium and mercury in wetland plants 总被引:9,自引:0,他引:9
The role of rhizosphere bacteria in facilitating Se and Hg accumulation in two wetland plants, saltmarsh bulrush (Scirpus robustus Pursh) and rabbitfoot grass (Polypogon monspeliensis (L.) Desf.), was studied. Ampicillin-amended plants (i.e., with inhibited rhizosphere bacteria) supplied with Na2SeO4 or HgCl2 had significantly lower concentrations of Se and Hg, respectively, in roots than plants without ampicillin. These results
were confirmed by inoculating axenic saltmarsh bulrush plants with bacteria isolated from the rhizosphere of plants collected
from the field; these plants accumulated significantly more Se and Hg compared to axenic controls. Therefore, rhizosphere
bacteria can increase the efficiency of Se and Hg phytoremediation by promoting the accumulation of Se and Hg in tissues of
wetland plants.
Received: 9 April 1999 / Accepted: 11 May 1999 相似文献