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1.
The kinetics of Hg desorption from selected freshwater sediments in the Canadian Prairies as influenced by a range of chloride
concentrations (0, 10−4, 10−3, 10−2, 2×10−2, 4×10−2, 6×10−2, 8×10−2, 10−1
M) were studied. The extent of the influence of Cl− concentrations on the increase of the rate of Hg release from the sediments in the fast desorption and slow desorption processes
varied from 2.5 to 10.5 times and 2.0 to 8.5 times, respectively. An abrupt increase in the Hg release from the sediments
was observed when the Cl− concentration was 2×10−2
M and higher. The increase of Hg release with increasing Cl− concentrations was attributed to the dissolution of the adsorbed Hg through its complexation with Cl−. The release of Hg was not affected by the ionic strength and the Na concentrations in the systems studied. The influence
of Cl- concentrations on the kinetics of the release of the sediment-bound Hg varied with the nature and properties of the
sediments. The data indicate that short-range ordered oxides of Al, Fe, and Mn and their complexes with organic components
merit close attention in studying the influence of Cl−, whose sources include deicing salts, fertilizers, animal wastes, and sewage effluents, on the rate of the dispersion of
Hg from freshwater sediments. 相似文献
2.
海南岛北部玄武岩上土壤发生研究Ⅱ.铁氧化物特征 总被引：2，自引：5，他引：2
研究了海南岛北部玄武岩上发育的不同风化成土年代土壤系列的铁氧化物特征。研究表明,随风化成土时间增加,土壤发生过程中形成的游离铁（Fed）以及铁游离度（Fed/Fet）增大,铁活化度（Feo/Fed）降低。穆斯堡尔谱分析显示风化成土时间从9×104a、64×104a至 181× 104a,土壤黏粒中形成的赤铁矿含量占铁氧化物的比例从16％、25％增至 48％。风化成土时间越短,土壤中针铁矿结晶程度越差。X-射线衍射结果表明土壤细土和黏粒中赤铁矿含量与风化成土时间呈正比增加。同时,土壤有磁铁矿含量减少、磁赤铁矿增加的趋势。 相似文献
3.
A. H. SINCLAIR 《European Journal of Soil Science》1979,30(4):775-783
The stable desorption parts of soil Quantity/Intensity isotherms were used to determine the contributions of initially exchangeable and non-exchangeable potassium to plant uptake from ten soils. The activity ratio, ARK= aK/√aCa, Mg at which K was first taken up from non-exchangeable sources varied from 3 × 10?3 to 8 × 10?3 M1/2 depending on the soil. Uptake rates of two categories of initially non-exchangeable K were linearly related to √times;. The first category appeared to be close to equilibrium with the initially exchangeable K, and gave effective diffusion coefficients of 10?7 cm2 s?1 for four soils. The second category gave diffusion coefficients from 10?20 to 10?22 cm2 s?1, probably came from internal surfaces of micaceous clays, and began to be released at activity ratios below 3 × 10?4 to 6 × 10?4 M1/2 depending on soil type. The soils fell into three groups, broadly consistent with soil series, on their ability to release the second category of potassium. 相似文献
4.
《Communications in Soil Science and Plant Analysis》2012,43(19-20):3175-3180
Abstract Changes in pH values during 12 weeks incubation in soils treated with acidified sawdust (ACD‐SD)‐treated soils ranged from 5.03 to 5.89, from 9.88 to 10.35 in soil treated with alkalized sawdust (ALK‐SD), and ranged from pH 6.88 to 7.35 in untreated sawdust‐amended soil. In unamended soil, pH values were 6.80 to 7.35. Bacterial populations over the 12 weeks in ACD‐SD‐treated soils increased from 5×106 to 167×106 colonies while bacterial populations in ALK‐SD‐treated soils increased from 2×106 to 54×106. Fungal populations increased from 6×104 to 11,333×104 colonies per gram soil in ACD‐SD treated soils over the 12 week incubation. Untreated sawdust and control soil did not result in any significant changes in the fungal populations. 相似文献
5.
Fulvic acid is a water-soluble humic material that occurs widely in soils and waters and that tends to form water-soluble and water-insoluble complexes with a variety of metal ions, some of which are toxic. This paper presents information on the conditions under which the different types of FA-metal complexes are formed. The solubility in water, separately and after mixing, of FA (2 to 30 mg/100 ml) and eleven metal ions (Fe(III), Al, Cr(III), Pb, Cu, Hg(II), Zn, Ni, Co, Cd and Mn; 1 × 10?5 moles of each metal ion) was investigated over the pH range 4 to 9. After mixing, the solubility of the components was significantly affected by pH only when less than 20 mg of FA was present. As the systems became richer in FA (22 to 30 mg), most of the metal ions remained in the aqueous phase, likely due to the formation of FA-metal complexes, inhibiting the formation of metal hydroxides. The order in which the eleven metal ions tended to form water-insoluble FA-metal complexes depended on the pH. At pH 6 it was: Fe = Cr = Al > Pb = Cu > Hg > Zn = Ni = Co = Cd = Mn. This order appeared to correlate with the valence, 1st hydrolysis constants and effective hydrated ionic diameters of the metal ions. In general, FA/metals weight ratios of > 2 favored the formation of water-soluble FA-metal complexes; at lower ratios, water-insoluble complexes, which could accumulate in soils and sediments, were formed. 相似文献
6.
Inga Herrmann Amir Jourak Annelie Hedström Staffan Lundström Maria Viklander 《Water, air, and soil pollution》2014,225(1):1-11
The distribution of selected elements in individual fractions of organic matter from anthropogenically contaminated soils was investigated. The attention was paid especially at Hg. Furthermore, contents of S, Mg, Mn, Fe, Cu, Zn and Pb were also measured. The decomposition of organic matter to particular fractions was carried out by the resin DAX-8. Ten soil samples were collected, and the Advanced Mercury Analyzer (AMA-254) was used for the determination of the total Hg content. The two highest Hg values reached up to the concentration 10.5 mg kg?1, and in the highest one, it was almost 29 mg kg?1. In each extract, mercury was measured by inductively coupled plasma mass spectrometry (ICP-MS), for other elements, inductively coupled plasma optical emission spectrometry (ICP-OES) was applied. Results of the analysis show that the Hg content bound to the humic acids is inversely proportional to the content of Mg, Mn, Fe and Cu. However, this dependence was not confirmed by the samples with the mercury content above 10 mg kg?1. In the case of fulvic acids, the relationship between Hg and S was observed and has again an inverse character. 相似文献
7.
Soil microbial habitats are altered by mulching, a common practice in urban areas during which vegetation is removed and soils covered to suppress weeds and retain moisture. Soil microorganisms drive nitrogen-cycling processes in mulched soils, because living plants no longer take up ammonium-N released during decomposition of residual organic matter. Because ammonia oxidizers carry out the first, rate-limiting step of nitrification, we compared ammonia oxidizers in experimental, unfertilized plots of mulched and vegetated soils. We hypothesized that mulched and vegetated soils would support contrasting communities of bacterial and archaeal ammonia oxidizers, as determined by quantitative PCR and primers specific for genes encoding ammonia monooxygenase subunit A (amoA). Clone libraries of archaeal amoA also were constructed to compare diversity in soil cores, duplicate blocked plots, and treatments (bark-mulched, gravel-mulched, and unmanaged old field vegetation). Gene copies from ammonia-oxidizing bacteria (AOB) ranged from 2.2 × 106 to 2.7 × 107 gene copies per gram dry soil and did not differ across treatments. In contrast, gene copies from ammonia-oxidizing archaea (AOA) ranged from 9.1 × 105 to 1.0 × 108 copies per gram dry soil, with bark-mulched soils having significantly lower abundance. Community structure of AOA in gravel-mulched soils was distinct from the other two treatments. At 97% amino acid similarity, 22 operational taxonomic units, or OTUs, were identified, with only one OTU found in all 18 clone libraries. This ubiquitous OTU-1, which was highly similar to published amoA sequences recovered from soils, comprised 55% of all 482 translated sequences. Greater variability in OTU richness was observed among cores from mulched soils than from vegetated soils. Our observations supported our hypothesis that AOA communities differ in mulched and vegetated soils, with mulched soils providing altered and variable microniches for these N cycling microorganisms. 相似文献
8.
Seasonal Monitoring of Hydrocarbon Degraders in Alabama Marine Ecosystems Following the Deepwater Horizon Oil Spill 总被引：1，自引：0，他引：1
Agota Horel Behzad Mortazavi Patricia A. Sobecky 《Water, air, and soil pollution》2012,223(6):3145-3154
Following the Deepwater Horizon explosion and crude oil contamination of a marsh ecosystem in AL in June 2010, hydrocarbon-degrader microbial abundances of aerobic alkane, total hydrocarbon, and polycyclic aromatic hydrocarbon (PAH) degraders were enumerated seasonally. Surface sediment samples were collected in October and December of 2010 and in April and July of 2011 along 40?C70-m transects from the high tide to the intertidal zone including Spartina alterniflora-vegetated marsh, seagrass (Ruppia maritima)-dominated sediments, and nonvegetated sediments. Alkane and total hydrocarbon degraders in the sediment were detected, while PAH degraders were below detection limit at all locations examined during the sampling periods. The highest counts for microbial alkane degraders were observed at the high tide line in April and averaged to 8.65?×?105 of cells/g dry weight (dw) sediment. The abundance of alkane degraders during other months ranged from 9.49?×?103 to 3.87?×?104, while for total hydrocarbon degraders, it ranged between 5.62?×?103 and 1.14?×?105 of cells/g dw sediment. Pore water nutrient concentrations (NH 4 + , NO 3 ? , NO 2 ? , and PO 4 3? ) showed seasonal changes with minimum values observed in December and April and maximum values in October and July. Concentrations of total petroleum hydrocarbons in sediments averaged 100.4?±?52.4 and 141.9?±?57.5?mg/kg in January and July, 2011, respectively. The presence of aerobic microbial communities during all seasons in these nearshore ecosystems suggests that an active and resident microbial community is capable of mineralizing a fraction of petroleum hydrocarbons. 相似文献
9.
P.J.A. Howard P.J. Loveland R.I. Bradley F.T. Dry D.M. Howard D.C. Howard 《Soil Use and Management》1995,11(1):9-15
Abstract. England and Wales have 155 314 1 × 1 km squares, of which 140049 have more than 50% soil cover. The total soil organic carbon content, based on the dominant soil series and dominant land cover type, is estimated to be 2773 × 106 t C. Scotland has 84929 1 × 1 km squares, of which 82 420 have a nominated dominant soil series. The total soil organic carbon content is estimated to be 19011 × 106 t C, 6.85 times the total organic carbon content of the soil of England and Wales. The total organic carbon content of the soil of Great Britain is estimated to be 21 784 × 106 t C, of which 87% is in Scottish soils and 75% is in Scottish peats. A map of the mean soil organic carbon content of 10 × 10 km squares of the National Grid using classes of equal range illustrates the narrow range of organic carbon contents of the soils of England and Wales and the dominance of organic carbon in Scottish soils. A map using the same data, but with classes of unequal ranges increasing in size with increasing carbon content, is better for showing detailed differences within England and Wales. 相似文献
10.
The long-term fertilization results in accumulation of phosphorus especially in the top layer of the soils. Inundation of agricultural lands leads to a switch to anaerobic soil condition, causing reduction of iron and leaching of phosphate simultaneously. From the ecological and environmental perspective, high nutrients flux especially phosphorus will increase the possibility of eutrophication in aquatic system. The fern Azolla had a good potential to adsorb phosphorus, it also has distinctive nitrogen-fixing capacity. We conducted a 10-week aquarium experiment to investigate the phosphorus release capacity from two agricultural soils in the Netherlands with different Fe and P concentrations but comparable Fe/P ratios. Besides, the research questions rose to whether Azolla could use the mobilized phosphate released from the soils for growth. We also tried to find an effective indicator to estimate the actually phosphate mobilization from sediment to water layer. Results showed that the soils with high Fe and P concentrations had higher phosphate release rate compared with the soil with low Fe and P concentrations. Pore water Fe: PO43? ratios were valid to identify P release to surface water, when the Fe: PO43? ratios less than 8 mol mol?1 substantial phosphorus mobilization occurred. The conclusions showed that the actual mobilization of phosphate is more important than the phosphorus retained in the sediments for the internal PO43? fluxes. From 10-week experimental results, we found that Azolla can reuse the phosphate retained in soils thus removed the mobilized phosphate in a moderately low surface water nutrient loading. 相似文献
11.
Edson Campanhola Bortoluzzi Danilo Rheinheimer dos Santos Maria Alice Santanna Laurent Caner 《Journal of Soils and Sediments》2013,13(6):1093-1105
Purpose
This study investigated desorption of potassium (K) and phosphorus (P) from soil and river suspended sediments sampled during a storm event in a Brazilian watershed traditionally used for tobacco plantations.Material and methods
Suspended sediment samples were collected automatically at the outlet of the watershed and were grouped into three phases: beginning (phase a), middle (phase b) and final stages (phase c) of the storm event. Granulometric and mineralogical characterisation of soils (0 to 0.20 m depth) and suspended sediments was determined, and K and P extractions were performed using a cation and anion exchange resin (CAER) membrane. A kinetic modelling approach was used to estimate the amount of K and P desorbed.Results and discussion
Clay-sized (<2 μm) content of the soils were all <21 %. Kaolinite, smectite (partially with hydroxy-Al interlayer) and a small amount of illite were found in the clay fraction of the different soils. The clay-sized fractions in sediments of phases a, b and c of the storm event were 49, 52 and 72 %, respectively. Smectite (>90 %) and kaolinite (<10 %) were the dominant clay minerals in the suspended sediments. The values of labile P and potentially available P of suspended sediments were higher than those for soils. In sediments, the highest values of labile P (325 mg kg?1) and labile K (4,458 mg kg?1) were found in phase c and in phase a, respectively.Conclusions
Particle size distribution and clay mineralogy of soils differed from those of suspended sediments collected during the storm event. By comparison with the watershed soils, suspended sediments collected during the storm event were enriched in fine particles composed mainly of smectite, and this may explain their P and K desorption behaviour. This suggests particle size and clay species selectivity processes during the transfer of sediment particles from soils to aquatic systems. The amounts of P and K desorbed from the suspended sediments in the three phases of the storm event were much larger than those desorbed from soils. This indicates that rainfall promoted the transfer of these nutrients to the watercourses. 相似文献12.
The air Hg content at and near the summit of Mt. Etna is approximately 500- to 2000-fold lower than it is in the atmospheres around Antarctic, Hawaiian and Icelandic volcanoes. In contrast, the soils and plants on Mt. Etna show only 10- to 30-fold reductions in Hg content; in other words, there is at least a ten-fold enrichment relative to air. This disparity called into question the source of Hg in the vegetation and upper soil layers. Soils and a variety of plant species were analyzed for Hg, Fe, Cu, and Mn content at a number of stations on Mt. Etna including several also sampled for air Hg, and compared with the data for plants and soils from other volcanic and non-volcanic locations, especially Hawaii, Africa and Iceland. Etna vascular plants do not accumulate Hg, and lichens do so only to a moderate extent. Relative to their Fe content, however, all the Etna soils are enriched in Hg, but the reverse is true for Cu relative to Hg. The plants, on the other hand, when compared with their soils, are enriched in Hg relative to Cu. By comparing Fe/Hg atomic ratios for plants and soil, we calculated an Enrichment Factor (EF) for Hg. This value ranged from 19 to 102 for Etna, and 19 to 184 for all subtropical plants discussed here. The Hg EF for Icelandic samples was ca. 823, reflecting other environmental/geochemical determinants. No net surface deposition of Hg takes place on Etna from plant or atmospheric sources, and the relative Hg contents of soils and plants do not show a consistent relation to air Hg concenctration. Nevertheless, the plant/soil Cu and Hg ratios (CR) vary similarly as do the atomic ratio (AR) values for Fe and Hg. We conclude from these relationships that the atmosphere is not a major source of plant (or soil) Hg and that the likely alternatives are: release at some relatively remote point in time, but not to any significant degree since; release into the atmosphere as Hg = species other than Hg0; or movement from very deep subsurface compartments. These alternatives are not mutually exclusive. It is highly improbable that summit emissions constitute a significant source of Hg in the Mediterrean Basin. 相似文献
13.
《Soil Science and Plant Nutrition》2013,59(4):420-429
Abstract Viruses are the most abundant biological entities in marine and freshwater environments. Many studies have shown the ecological importance of viruses in the primary production and microbial food web in aquatic environments. However, no studies have examined viral abundance in the floodwater of paddy fields. The present study surveyed the abundance of virus-like particles (VLPs) and bacteria in the floodwater of a Japanese paddy field under a long-term fertilizer trial since 1925 during the rice cultivation period. Virus-like particles and bacterial abundances in the floodwater ranged from 5.6 × 106 to 1.2 × 109 VLPs mL?1 and from 9.2 × 105 to 4.3 × 108 cells mL?1 with mean abundances of 1.5 × 108 VLPs mL?1 and 5.1 × 107 cells mL?1, respectively, and increased with an increase in the turbidity of the floodwater with suspended particles. The magnitude of seasonal variation was more than 50-fold for VLP abundance and 100-fold for bacterial abundance. The virus-to-bacterium ratios fluctuated over the rice cultivation period, ranging from 0.11 to 72 and their increase correlated with the decrease in bacterial abundance. Our results suggest that viral abundance in the floodwater of paddy fields is larger than in natural marine and freshwater environments. 相似文献
14.
RHIZOSPHERE MICROBIAL POPULATIONS IN CONTAMINATED SOILS 总被引：2，自引：0，他引：2
NICHOLS T. D. WOLF D. C. ROGERS H. B. BEYROUTY C. A. REYNOLDS C. M. 《Water, air, and soil pollution》1997,95(1-4):165-178
Rhizosphere microbial populations may increase bioremediation of soil contaminated with organic chemicals. A growth chamber study was conducted to evaluate rhizosphere microbial populations in contaminated and non-contaminated soil. Alfalfa (Medicago sativa L.) and alpine bluegrass (Poa alpina L.) were grown in soil containing a mixture of organic chemicals for 14 weeks. The equal millimolar mixture of hexadecane, (2,2-dimethylpropyl)benzene, cis-decahydronaphthalene (decalin), benzoic acid, phenanthrene, and pyrene was added at levels of 0 and 2000 mg/kg. Organic chemical degrader (OCD) populations were assessed by a Most-Probable-Number technique, and bacteria and fungi were enumerated by plate count methods. Different methods for expressing OCD rhizosphere populations were investigated to determine the effect it had on interpretation of the results. At 9 weeks, the OCD numbers were significantly higher in rhizosphere and contaminated soils than in bulk and non-contaminated soils, respectively. Alfalfa rhizosphere OCD levels were 4 × 107/g for contaminated and 6 × 106/g for non-contaminated soils. Bluegrass rhizosphere OCD levels were 1 × 107/g and 1 × 106/g in contaminated and non-contaminated soils, respectively. Selective enrichment of OCD populations was observed in contaminated rhizosphere soil. Higher numbers of OCD in contaminated rhizospheres suggest potential stimulation of bioremediation around plant roots. 相似文献
15.
A. O. Olaleye A. O. Ogunkunle B. N. Singh G. E. Akinbola F. O. Tabi O. O. Fayinminu 《Journal of plant nutrition》2013,36(8):1336-1352
ABSTRACT Iron (Fe) toxicity is a widespread nutritional soil constraint affecting rice production in the wetland soils of West Africa. Critical levels of total iron in plant causing toxicity is difficult to determine as different rice cultivars respond to excessive Fe2 + in various ways in what is called “bronzing” or “yellowing” symptoms (VBS). An investigation was conducted to evaluate the relationship between plant growth and nutrient ratios at four iron levels (1000, 3000, 4000 μ g L?1) and control. This involved two rice cultivars (‘ITA 212’ and ‘Suakoko 8’), and two soil types (Aeric Fluvaquent and Aeric Tropaquept). The experimental design was a 2 × 2 × 4 factorial in a completely randomized fashion with four replications. The results showed that nutrient ratios [phosphorus (P)/Fe, potassium (K)/Fe, calcium (Ca)/Fe, magnesium (Mg)/Fe, and manganese (Mn)/Fe), Fe content, and Fe uptake vary widely with the iron levels as well as with the age of the cultivars. The iron toxicity scores expressed as VBS increased with increasing Fe2 + in the soils, resulting in simultaneous reduction of the following variables: plant height, tiller numbers/pot, relationships grain yield (GY) and dry matter yield (DMY). There were no significant difference between nutrient ratios, Fe contents, Fe uptake, the GY and DMY of both rice cultivars on both soil types. Multiple stepwise regression analysis showed that Fe uptake and Fe contents contributed 42% and 17% respectively to the variation in the grain yield of ‘ITA 212’ on Aeric Tropaquept. On both soil types and cultivars, Fe uptake and Fe content contributed between 26 and 68% to the variation in the DMY, while the nutrient ratios (P/Fe, K/Fe, Ca/Fe, and Mn/Fe) contributed between 3% and 13% DMY. Thus, it could be concluded that iron toxicity in rice is more a function of a single nutrient (Fe) rather than nutrient ratios. 相似文献
16.
Anaerobic ammonium oxidation (anammox) and nitrite-dependent anaerobic methane oxidation (n-damo) are two recently discovered processes in the nitrogen cycle that are catalysed by anammox bacteria and n-damo bacteria, respectively. Here, the depth-specific distribution and importance of anammox bacteria and n-damo bacteria were studied in an urban wetland, Xixi Wetland, Zhejiang Province (China). Anammox bacteria related to Candidatus Brocadia, Candidatus Kuenenia and Candidatus Anammoxoglobus, and n-damo bacteria related to “Candidatus Methylomirabilis oxyfera” were present in the collected soil samples. The abundance of anammox bacteria (2.6–8.6 × 106 copies g−1 dry soil) in the shallow soils (0–10 cm and 20–30 cm) was higher than that (2.5–9.8 × 105 copies g−1 dry soil) in the deep soils, whereas the abundance of n-damo bacteria (0.6–1.3 × 107 copies g−1 dry soil) in the deep soils (50–60 cm and 90–100 cm) was higher than that (3.4–4.5 × 106 copies g−1 dry soil) in the shallow soils. Anammox activity was detected at all depths, and higher potential rates (12.1–21.4 nmol N2 g−1 dry soil d−1) were observed at depths of 0–10 cm and 20–30 cm compared with the rates (3.5–8.7 nmol N2 g−1 dry soil d−1) measured at depths of 50–60 and 90–100 cm. In contrast, n-damo was mainly occurred at depths of 50–60 cm and 90–100 cm with potential rates of 0.7–5.0 nmol CO2 g−1 dry soil d−1. This study suggested the niche segregation of the anammox bacteria and n-damo bacteria in wetland soils, with anammox bacteria being active primarily in deep soils and n-damo bacteria being active primarily in shallow soils. 相似文献
17.
The usage of sewage sludge on agricultural lands is an effective and inexpensive practice that provides nutrients for crops. A successful legume crop also depends on the survival of Rhizobium in the soil environment. The number of R. japonicum (USDA 110) in treatment groups containing various soil-to-sludge ratios (control, 13:1, 9:1 and 5:1) during incubation for 1, 21 and 42 days was investigated. The control group contained soil without sludge. Mecklenburg clay and Enon sandy loam soils (both are fine, mixed, thermic, ultic Hapludalfs) were used. All treatments were adjusted to pH 6.7 and brought to 75% of field capacity with 1 ml inoculum (9 × 108 cells ml? 1) and distilled water. Samples were incubated at 25 C and monitored periodically for the number of surviving R. japonicum (USDA 110) organism by the plant infcction-MPN method. Strains were identified by gel-immunodiffusion. Recovery of rhizobia from both soils was < 1% in all treatment groups after 42 days. However, for control, 13:1, 9:1 and 5:1 groups, the percentage recovery was higher in Enon sandy loams (7.9, 2.3, 2.3 and 2.3%, respectively) at 21 days. Recovery of rhizobia in the 5:1 group from both soils was 7.9% after 1 day, whereas control values were 92%. A decline in rhizobial populations in higher sludge soils may be due to the heavy metals present and available during mineralization of sludge in soils. However, the number of R. japonicum that survived to 21 days was 1.7 × 105g?1 and 1.7 x 106g?1 for Mecklenburg clay and Enon sandy loam soils with highest sludge, respectively. 相似文献
18.
W. A. Glooschenko J. Capocianco J. Coburn V. Glooschenko 《Water, air, and soil pollution》1981,15(2):197-213
As part of a water quality study on Rattray Marsh, a suburban marsh located on the Lake Ontario shoreline at Mississauga, Ontario, a sedimentary geochemistry study was initiated. In general, Cu, Zn, Pb and Hg were higher in concentration than in local soils, but lower than Lake Ontario recent sediments. Over the past century, an approximate two-fold increase in the sedimentary levels of Cu, Zn, Co, Cr and Ni occurred, while Cd increased nearly 4 ×, and Pb, 8 ×. No correlation was found between metals and organic carbon, and the metals appear to be associated with silts and clays as evidenced by (1) factor analysis of geochemical data, (2) higher concentrations in areas of the marsh subjected to high sediment deposition, and (3) analysis of a suspended sediment sample from Sheridan Creek, the main tributary basin of the marsh. Organochlorine contaminants include p,p1-DDE,p,p1-DDD,p,p1-DDT, a-chlordane, PCB, mirex and HCB. 相似文献
19.
Xue-Ping Chen Hao-Yu Chen Jing Sun Xu Zhang Chi-Quan He Xiao-Yan Liu Xin Huang Min Yang Fu-Shun Wang Kristiina Väänänen 《Journal of Soils and Sediments》2018,18(11):3324-3333
Purpose
Mining is a common source of metals in aquatic ecosystems. Metal loading in the environment is thought to be a selective pressure that induces compositional and functional changes within the affected microbial community in the sediment. This study aims to explore shifts in the diversity, structure, and functional gene abundance of microbial communities in the sediment of the copper mining-induced contaminated lakes in Finland.Materials and methods
The sediment microbial community structures and abundance of the functional groups involved in carbon/nitrogen/sulfur cycling in four lakes located downstream from metal mines (Kirkkoselkä (KS), Junttiselkä (JS), Laakajärvi (LJ), and Sysmäjärvi (SJ)) and one reference lake (Parkkimanjärvi (PJ)) in Finland were compared using high throughput sequencing and quantitative PCR.Results and discussion
Compared to the PJ reference lake sediment, the relative abundances were higher for Bacteroidetes, Gemmatimonadetes, Acidobacteria, and Nitrospirae but lower for Firmicutes and Alphaproteobacteria in the mine-contaminated sediment samples. The number of copies of copper-resistant genes (copA) in the two copper-contaminated sediments (5.34 × 106 and 4.95 × 106 copies ng?1 DNA for KS and JS, respectively) was significantly higher than that in the PJ sediment (1.33 × 106 copies ng?1 DNA). Methanogens (mcrA gene) accounted for 5.09–11.5% of the total archaea (16S rRNA) in these lake sediments. In addition, ammonia-oxidizing archaea (amoA gene) in the LJ sediment accounted for 36.0% of the total archaea but only 0.83–1.63% in the sediment of other lakes. The abundance of eight investigated functional groups accounted for 28.8% of the total bacteria in the PJ sediment but less than 1.3% in the metal-contaminated sediments. The canonical correspondence analysis showed that the microbial community structure of Lake LJ was scattered far from the other lakes and was significantly correlated with nitrate; the community structural change in the JS and KS sediments was positively correlated with copper or negatively correlated with nitrate concentration.Conclusions
These results indicate that the sedimentary indigenous microbial community may shift its composition and structure as well as its function to increase its adaptability and/or resistance to metal-contaminated freshwater sediments.20.
Yan J. Guo Hong J. Di Keith C. Cameron Bowen Li Andriy Podolyan Jim L. Moir Ross M. Monaghan L. Chris Smith Maureen O’Callaghan Saman Bowatte Deanne Waugh Ji-Zheng He 《Journal of Soils and Sediments》2013,13(4):753-759