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1.
A groundwater system in a karstic terrain is easily subject to pollution and its remediation is difficult once contaminated by human activities. The groundwater samples collected in both winter and summer seasons at Guiyang, SW China, show a wide range of variations in chemical composition and dominance of Ca^2＋, Mg^2＋, SO4^2-, and HCO3^- ions. The anthropogenic inputs include Cl^-, NO3^-, SO4^2-, Na^＋, and K^＋, as judged from the relationships between different elemental ratios and sewage samples. Cl^- concentrations of all water samples in the study area vary from 0 to 3.9 mmol/L in winter and are higher than in summer. In most of the samples, SO4^2- concentrations are high, ranging from 0.1 to 11 mmol/U The studies show that the cycling of sulfur plays an important role in controlling water chemistry and fate of contaminants in groundwater. In order to understand the source of SO4^2- and the geochemical cycling of some elements in the karstic groundwater environment, we have carried out a study on the variations of S and Cl isotope compositions, in addition to other isotopic tracers such as ^87Sr/^86Sr and δ^13C studied previously. The δ^37Cl values of the groundwater samples present a seasonal variation, ranging from 0.00‰ to ＋2.03‰ in winter and from -1.46‰ to ＋0.29‰ in summer. The surface water samples show a similar range of variations as observed for groundwater. Two rainwater samples collected at Guiyang have a distinct isotopic signature （mean value is -3‰） compared to the δ^37Cl values reported in literature. These results indicate that ground water is mainly derived from precipitation and suggest a fast recharge of the karst system by surface water.  相似文献   

2.
Even though, application of industrial effluent water may alleviate the irrigation water shortage in dry regions such as Iran, but uncontrolled discharge into environment and agricultural land may cause unirreversible harmful damage to environments. Therefore, application of industrial effluent water should consider the environmental consequences such as soil, ground water and food contamination. In this study the effect application of Zob-Ahan effluent water for irrigation water and seepage from evaporation ponds on the chemical composition of surrounding well-water were seasonally investigated from April to March in 2003. The water from the selected well was sampled and analyzed for pH, EC, nitrate, hardness, TSS, TDS, and cations including Na^＋, Ca^2＋, Mg^2＋, anions including SO4^2-, CO3^2-, HCO3^-, Cl^-, and heavy metals including Pb, Cd, Cu, Fe, Cr, Mn, Co, and Zn . The results were compared with standard levels for ground water resources, irrigation water, and direct human consumption. The result shows that the ground water in the vicinity of effluent water application fields and evaporation ponds is contaminated and the concentrations of NO3, Cl and Fe are higher than standard permissible levels for ground water resources. For irrigation or discharge into absorption well the heavy metal concentrations of Cu, Cr, Co, and Fe are limiting.  相似文献   

3.
The Raniganj Coalfield is the oldest coalfield in India that has been continuously and extensively mined since the late eighteenth century. The present study reports a geochemical investigation and environmental quality assessment using soil and water in the area surrounding a stream, locally known as Singaran Nala （Nala means storm water drains in Bengali）, in the Raniganj Coalfield. Soil （top soil, mud, silty clay and laterite） and rock samples （sandstone and shale） were collected from the study area and were analyzed for trace metals （Cr, Cu, Fe, Mn, Ni and Zn）. Surface waters from the stream and the Damodar River as well as ground waters from hand pumps and underground mine pits were collected. Water samples were analyzed for major ions （Na^＋, Ca^2＋, Mg^2＋, Cl^-, HNO3^- and SO4^2-） and trace metals （Cu, Fe, Mn, Ni, and Zn）. Trace metal concentrations in soil samples are found higher than the average world soil composition. Nevertheless, trace metal （Cr, Cu, Ni and Zn） concentrations in soils exceed or reach the maximum allowable concentrations （MAC） proposed by the European Commission for agricultural soils. In particular, Ni concentrations exceed the typical value for cultivated soils. Chromium, Cu and Ni concentrations in laterite and Cr concentration in topsoil exceed the ecotoxicological limit.  相似文献   

4.
A comprehensive study on the chemical composition of wet precipitation was carried out from January 2004 to December 2004 at Jinhua, China. All samples were analyzed for pH, electrical conductivity and major ions （F, Cl, NO3,. SO4^2-, K^＋, Na^＋, Ca^2＋, Mg^2＋. and NH4^＋）. The results showed that SO4^2- is one of the dominant anions, accounting for 66.1% of the measured anions in precipitation, while NH4^＋ and Ca^2＋ account for 56.6% and 33.4% of the measured cations, respectively. Even though the concentrations of SO4^2- and NO3^- were not high relative to those in the northern areas of China, rainwater in the studied area is typically acidic with a volume-weighted mean pH of 4.54 due to the lack of neutralization in precipitation. The fractional acidity value suggested that about 76% of acid was neutralized by alkaline constituents. On the other hand, H^＋ showed no significant correlation with other ionic species, which indicates that its acidity might be attributed to the comprehensive effect of all the acidifying and neutralizing ions rather than one major ion in precipitation. A good correlation between Ca^2＋ and Mg^2＋, as well as between Na^＋ and Cl^-, indicated these ions are commonly of crustal and marine origin, respectively. Other relatively good correlations were observed between NH4^＋ and SO4^2-, Ca^2＋ and SO4^2-, Mg^2＋ and SO4^2-, Mg^2＋ and NO3^-, and Mg^2＋ and Cl^-. These results were attributed to the atmospheric chemical reactions of the acids H2SO4, HNO3 and HCl with alkaline compounds such as NH3 and/or carbonate materials. High enrichment factor of marine source for SO4^2-, Ca^2＋ and K^＋ indicated that large amounts of these ions came mainly from a non-marine source. Similarly, a high enrichment factor of soil for SO4^2-, NO3^- and CI also suggested that most of these ions did not come from soil source.  相似文献   

5.
Acid rain is one of China＇s major environmental problems and emissions of sulphur and nitrogen are still increasing. The acid rain situation in China is somewhat different from what is seen in Europe and North America. Sulfur deposition is very high, but there is also very high deposition of calcium and other base cations. The sources of atmospheric Ca are not well understood, although it is important for understanding long term impacts of acid deposition. The fate of S, N and Ca^2＋ in the catchment is crucial for the future development of the acidification situation of soils and waters in China. Very few studies presenting catchment input-output ion budgets in Chinese natural environments exist and there are several unknown factors regarding processes. Here, we present annual input-output budgets for three years （2001-2003） for major ions for four forested catchments in China receiving different loads of acid deposition. For the two sites receiving the highest SO4^2- inputs, the input-output budget for the upper 50 cm of soil is approximately balanced. For the most remote site the soil is a net sink for SO4^2-, suggesting that the pool of adsorbed SO4^2- in the soil is building up. This is in agreement with the fact that the site so far has received only moderate SO4^2- inputs. For the southemmost, the subtropical site there is a loss of SO4^2- in the soil, which at least partly may be related to high uptake from the dense and highly productive forest at the site. The Ca^2＋ budgets for the upper 50 cm of soil show large variations both within and between sites. For most locations there is production of Ca^2＋ in the soil that can be explained by weathering, and variation between years related to hydrology that can be explained by ion exchange. However, at some plots at the site receiving very high inputs of both SO4^2- and Ca^2＋, there is an unknown sink of Ca^2＋ in the soil at some plots.  相似文献   

6.
Variability of aquatic chemistry in central Guizhou karst region, China   总被引：1，自引：1，他引：0  
It is necessary to understand the aquatic chemical characterstics of natural surface fresh water for water quality assessment.The chemical data from different kinds of water in the central Guizhou karst area showd that spring water from carbonate rock cracks(crack-water)is of neutrality or meta-alkalinity and [C] Ca II type.The amounts of all ions and the concentrations of HCO3^- and Ca^2 were higher in the autumn than in the spring,The crack-water was influenced by the infiltration of surface water in the process of erosion and /or trans-portation with decreasing HCO3 and increasing pH,SO4^2-,Cl^-,K^ and Na^ during running in a certain distance on the land surface .In particular,the chemical compositions of the waters at Tianxingqiao(upper-stream),Shuiliandong(mid-waterfall)and Luoshuitan(down-pool)near the Huangguoshu Waterfall were much different from those of the crack-water.The concentration of SO4^2-,Na^ ,Fe^3 and NO3^- varied closely with seasons.The CaCO3 deposited violently with CO2 release in the spring ,In Lake Hongfeng the HCO3^-/SO4^2- equivalent ratios were only 2.1-2.4 ,but Ca^2 /Mg^2 up to 2.4-4.2.The Cl^- concentration increased by a factor of 1 and Na^ by order of magnitude relative to the spring water.These indicated the increase in artificial pollutant discharge in the Lake Hongfeng watershed.In addition,Proewater in the soils covering carbonate rocks belongs to strongly mineralized water,The obvious differences in water quality were controlled by carbonate deposition,sulphate mineralization and nitrogen fixation as well as ammonification.It is indicated thaty the chemical compositions in the waters from the karst region were unstable and changeable.  相似文献   

7.
Gneiss-distilled water interaction at room temperature was investigated with batch-reactors to study water-rock reaction and geochemical evolution of the aqueous phase with time. The ion concentrations in water were controlled not only by the dissolution of primary minerals, but also by the precipitation of secondary minerals. The decreasing fraction sizes of gneiss could favor dissolution and precipitation simultaneously. Ca^2 and K^ were the major cations, and HCO3^- was the major anion in water. All the ions except Ca^2 increased in concentration with time. The Ca^2 release from the rock to the aqueous phase was initially much faster than the release of K^ , Na^2 and Mg^2 . But after about 5 - 24 hours, the Ca^2 concentrations in water decreased very slowly with time and became relatively stable. During the experiment, the water varied from the Ca-( K)-HCO3-type water to the K-Ca-HCO3-type water, and then to the K-(Ca, Na)-HCO3-type water. The water-gneiss interaction was dominated by the dissolution of Kfeldspar in the solution. The remaining secondary minerals were mainly kaolinite, illite and K (Mg) -mica.  相似文献   

8.
《中国地球化学学报》2006,25(B08):270-271
Rock weathering by carbonic acid is one of the important atmosphere CO2 sequestration. Actually, it depends on whether carbonic acid or other acids as weathering agents, which is important to understand the model of global carbon cycle. For example, sulfuric acid derived from oxidation of pyrite takes part in the rock weathering, which might counteract one part of CO2 drawdown by silicate weathering. In this study, chemicals and carbon isotopic composition of waters were determined in the Beipan River, Guizhou. The δ^13C values of dissolved inorganic carbon in the province, Southwest China. The values of the samples range from -13.1‰ to -2.4‰, which show a good negative correlation with the equivalent ratio of [HCO3]/（[Ca^2＋＋Mg^2＋]） and a good positive correlation with the equivalent ratio of [SO4^2-]/（[Ca^2＋＋Mg^2＋]） and [SO4^2-]/[HCO3^-]. The relationships suggest that sulfuric acid took part in carbonate weathering. Acid rain is thus a significant source of sulfuric acid to the karstic rivers of Guizhou Province.  相似文献   

9.
Red mud is the residue of bauxite processing for alumina. Red mud varies in physical, chemical and mineralogical properties due to differing mineral sources and refining processes adopted. In this project, red mud produced using a combined Bayer Process and Calcining （BPC） method was investigated. Red mud samples of varying ages were collected from the red mud storage facilities of the Zhenzhou Changcheng Aluminium Limited. The objective of this study is to （1） characterize the BPC red mud, and （2） examine the effects of this red mud on treating heavy metal-containing water and soil. Red mud samples were analyzed for pH, EC, water extractable salts and exchangeable basic cations, total element composition （by XRF）, mineral composition （by XRD）, micromorphological characteristics （by SEM） and thermogravimetric analysis （TGA）. The results show that the pH of the red mud decreased with increasing duration of storage time. The pH of the fresh, 5-year-old and 10-year-old red mud was 11.58, 10.56 and 9.61, respectively. Sodium dominated among the soluble cations, but the concentration of soluble Na decreased with increasing duration of storage time as a result of leaching. Cation exchange capacity as estimated from the sum of exchangeable cations also decreased with increasing duration of storage time, probably due to the decreasing pH which causes a reduction in negatively charged sites of the red mud. Calcium was the predominant exchangeable cation in the fresh red mud but the concentrations of exchangeable Ca markedly decreased in the old red mud which was dominated by exchangeable Na.XRF results showed that the red mud consists mainly of oxygen, calcium, iron, silicon, aluminium and titanium. Other important elements include sodium, carbon, magnesium and potassium. It is important to note that the red mud also contains elevated concentrations of radioactive elements, predominantly thorium （Th）, cerium （Ce） and rubidium （Rb）. XRD results showed that the major mineral types in the red mud were calcite, perovskite, illite, hematite and magnetite. There is a trend that the contents of magnetite decreased while the contents of hematite increased with increasing storage time, suggesting the conversion of magnetite to hematite. Observation using a SEM revealed that fresh red mud sample was amorphous while the 10-year-old red mud sample was fairly well crystallized. TGA results showed that the temperature at which the valley of weight loss occurred increased from 681.9℃ for fresh red mud to 722.9℃ for the 5-year-old red mud to 734.7℃ for the 10-year-old red mud. These results suggest that the contents of calcium carbonate increased with increasing storage time. Slow titration of the red mud samples with standardized acid solutions for two years indicated that the fresh red mud had an acid neutralizing capacity （ANC） of about 10 mol/kg while the ANC of old red mud samples was around 9 mol/kg. The ANC values obtained from the determination of BPC red mud here are much higher than those previously reported for red mud derived from the pure Bayer Process at the Queensland Alumina Limitd, Australia, and at the Pinggno Alumina Refinery, China.  相似文献   

10.
Geochemical cycling has received wide attention due to the need to understand the pathways of pollutants through our present environment. In this regard the Yangtze River plays a significant role in putting those pollutants into the East China SeafWorld Oceans. The Yangtze River is of high sedimentation rate and water discharge. The watershed covers variable climate regions from temperate to subtropical and from semiarid to humid. Twenty three （23） sampling locations at the estuary have been selected for understanding the dynamic relationships. The elements （Cl^-, SO4^2-, Na^＋, K^＋, and Ca^2＋） show conservative behavior during mixing of fresh water with saline water whereas Mg^2＋, Mn^2＋ show a non-conservative pattern . The relationships between Na^＋/SO4^2- and Cl^-/SO4^2- molar ratios show a mixing of more than two water sources.  相似文献   

11.
Stream water chemistry is dependent on the physical, chemical and biological processes occurring in the watershed. Understanding the governing mechanism of the stream water chemistry in a watershed is the first step for the water quality management. The study area drains a total catchment area of 1.46 km^2 and consists of forest （80%）, upland （15%） and rice paddy field （5%）. The studied area has two distinctive bedrocks, quartzite and schist. We periodically collected the stream water samples at mainstream and tributaries and the pH, electrical conductivity （EC）, alkalinity and the concentrations of cations and anions of the collected stream water samples were determined in the field and laboratory. The all collected water samples were nearly neutral and the EC and concentrations of Na, K, Ca, Sr, Si and HCO3 of the stream water samples collected from the schist terrain had greater values than those from the quartzite terrain. The mainstream running along the boundary of schist and quartzite terrains had the intermediate values of the tributaries. The stream water samples collected in and near the upland showed a high concentration of NO3^- than those of forest regardless the lithology. The stream pathway was also directly reflected on the chemistry of stream water. The stream water drained in the forest of quartzite terrain had the lowest values of alkalinity, EC and concentrations of cations and anions but the stream water drain in the upland of schist terrain had the highest values of EC and concentrations of cations and anions, especially NO3^-.  相似文献   

12.
Effects of mercury on ecosystems and human health are well documented. Human activities have significant impacts on transport, transformation, and fate of mercury in the natural environment. In this study, a gold mining area （Tongchuan）, an urban area （Xi＇an）, and a historical site （Qinshihuan Tomb） in Shaanxi Province, China, was chosen to study the effects of human activities on the transport, transformation, and fate of mercury in the area. Samples of atmospheric precipitate, soil, sediment, pomegranate, corn and those from wells and the rivers that flow through or flow by the city and from the mining area were collected. The EPA methods were used for sample preparation and analysis of these samples. These methods combine acid digestion, chemical reduction, purge and trap with Cold Vapor Atomic Fluorescence Spectrometry （CVAFS）. Preliminary results showed high total mercury concentrations in the water samples collected from a river in Tongguan County. The total mercury concentrations ranged from 133 to 188 ng/L in the water samples collected from the rivers flowing through Xi＇an City. The amount of total mercury in the soil/sediment samples which were collected in the vicinity of Xi＇an ranged from 31.8 to 83.2 ng/g. The total mercury concentrations in the samples of atmospheric precipitate （including rain and snow collected from Sep. 2005 to Jan. 2006） ranged from 106-298 ng/L.  相似文献   

13.
In early summer 2005, acidic, metal-laden water and clay-rich debris flooded down the flanks of the Chiginagak Volcano, Alaska. The estimated 3-million-m^3 discharge occurred during a rapid partial draining of a newly formed summit crater lake. Twenty-seven kilometers downstream from the source, Mother Goose Lake, a 500-million-m3 lake, was acidified from surface to bottom （pH ranged from 2.9 to 3.06）. All aquatic life was killed and salmon spawning runs were eliminated. The flood was accompanied by a simultaneous release of caustic volcanic gas and aerosols that followed the flood flow-path, and caused defoliation and necrotic leaf damage to vegetation in a 30-km^2 area along and above affected streams. In September 2005, approximately 1.4 million m^3 of acidic water remained and continued to drain from the summit crater lake. Water sampled 8 km downstream after considerable dilution from glacial meltwater was a weak sulfuric acid solution （pH-3, SO4^2- ～500 mg/L, and SO4^2-/Cl～10）. Cation proportions decreased in the order of Ca〉Fe〉Al〉Mg〉Na〉K. The eightfold predominance of Ca^2＋ over Mg^2＋ may reflect some dissolution of anhydrite, but only about 30% of the SO4^2- can be balanced by Ca^2＋. The anomalously high concentrations of Fe （-25 mg/L） and A1 （-18 mg/L） are derived from rock dissolution under the acidic conditions within the crater lake, and appear to be the most serious environmental threat in terms of metals. Further downstream, at stream and lake sites ranging from 8 to 40 km from the source, concentrations of cations remained high and hazardous metals such as As, Cr, and Cu were elevated well above background levels. Copper concentrations exceeded the U.S. Environmental Protection Agency＇s chronic exposure limit for aquatic life at most sampled sites and several sites exceeded the acute exposure limit.  相似文献   

14.
Through a systematic observation of water level and temperature, and a comprehensive analysis of the data on major/trace elements, nitrite, hydrogen-oxygen isotopes, the conclusion has been drawn that there are two relatively independent groundwater systems （cool water and hot water）, and the geochemical indicators of hot/cool waters are described. The cool water system is relatively enriched in Ca^2＋, Mg^2＋ and HCO3^-. Its TDS is relatively low, about 1400-1800 mg/L. The hot water system is relatively enriched in K^＋, Na^＋, Cl^- and SO4^2-. Its TDS is relatively high, about 2200-2300 mg/L. The cool water system is enriched in Ba, Ga, Cd, and the hot water system is enriched in B, Ti, Cr, Ni, Cu, Mo, Rb, and Cs, relatively. Especially, the contents of Rb and Cs in the hot water system are more than five times as high as those in the cool water system. The NO3^- contents of cool water discharged from the gold mine are relatively high, and those of hot water are extremely low. The 8D and 8-80 values follow an increasing order of surface water〉mine cool water〉mine hot water. The cool water comes mainly from the lateral supply of phreatic water, while the hot water comes mainly from the vertical supply of deeply circulating structure-fracture water. The ratio of cool water over hot water was estimated to be about 1：1 by a water quality model..  相似文献   

15.
Seawater flows towards the inlands along with the rivers and canals, through the process of infiltration and leaks in the ground water characterized by high concentrations of soluble salts. High salinity concentrations can make groundwater unsuitable for public consumption and surface water unsuitable for irrigation and agricultural activities. This study envisages the fluctuations of ground and surface water quality of Bentota area in the presence of seawater intrusion. The temporal and spatial variations of eleven water parameters were monitored by collecting the water samples during one year period. Spatial distributions were assessed by applying the Inverse distance weighted (IDW) interpolation method in Arc GIS 10.5 software. Water quality is assessed on the integration of all parameters in terms of an index based on the World Health Organization (WHO) standards. The significant linear relationship between the considered parameters of surface water (SW) and groundwater (GW) were identified applying correlation analysis using SPSS software. All parameters of surface water were above the permissible limits of WHO standards. Surface water quality index values with respect to 60% of canals show very poor quality (>1 250) of surface water indicating their unsuitability for irrigation activities. Those surface water bodies indicated very highly saline conditions during dry months. The spatial distribution of ground water quality index with respect to the highest parameter values of each sampling location indicates that 52.2% of total land extent of Bentota Divisional Secretariat Division (DSD) has good quality of ground water which is suitable for drinking. Its 47.2% of total land extent has poor quality of ground water for drinking purpose and less than 0.5% of the area consists of excellent or very poor quality of ground water in each. This study helps to manage coastal aquifers by understanding the extreme water quality conditions and coastal salinity.  相似文献   

16.
The Sipadan island is the only oceanic island found in Malaysia, and is popularly known for its beautiful corals and diving activities. The aquifer of the island is affected by seawater intrusion associated with groundwater exploitation. Geologically, the aquifer is composed of several series of Quaternary bioherm facies, and its recharge merely depends on rainfall. This research attempts to understand the chemical changes of the groundwater attributed to the salinization processes based on major ion composition （Ca^2＋, Mg^2＋, Na^＋, K^＋, HCO, SO, Cl^-）. The initial assessments were done in years 1993 - 1994, followed by subsequent assessment in years 2004-2005. Methods of analyses were adopted from APHA （1995）. The hydrogeochemical saturation indices （SI） were computed using the PHREEQC program in order to assess the state of equilibrium between groundwater and the minerals present. The results of analyses indicated that the groundwater has been highly enriched in Na^＋, SO and CI, reflecting an encroachment of saline water into the aquifer. The groundwater facies can be classified as sodium chloride （Na-Cl） water type. There are positive correlations （moderate to strong）, except HCO3^-, between the studied parameters. The weak and inconsistent correlation of HCO3^- with the cations and anions related to dissolved salts suggests that saltwater intrusion has an insignificant impact on the chemistry of HCO3^- in the groundwater. Strong correlations （r 〉0.70） exist among the major elements （Na^＋, Mg^2＋, K^＋, Cl^- and SO4^-） and salinity （EC）. These relationships clearly identify the main elements contributing to the groundwater salinity and their tendency to depict a similar trend of salinization pattern. Chloride has a major influence on the salinity of groundwater based on the positive and strong correlation that exist between Cl^- and EC （r=0.97）.  相似文献   

17.
Within a series of pot experiments with substrates sampled at heavily to moderately polluted sites of past metal mining activities, it was tried to influence the soil plant transfer of metals via addition of complexants, soil bacteria and perlite. Lettuce （lactuca sativa） was chosen as a universal accumulator plant. A wide range of concentrations in the samples ensures a rather general approach. The goal was to develop a strategy to enable plant growth at metal contaminated substrates for phytoremediation purposes. One contaminated mine tailing from Shiheung/Korea was treated with EDTA, NTA, citric acid, malic acid, NaCl, citrate＋NaCl, as well as compost, to provoke effects from chemical treatment. This should yield low molecular metal complexes in the soil solution and provide a carbon source to natural soil life. Other samples from Shiheung, from Okdong mine tailings, Okdong farmland, as well as from three contaminated sites from a medieval mine tailing at Oberzeiring/Styria/Austrias were treated with Cd- adapted soil bacteria, perlite, and soil bacteria and perlite, to impose of changes in microbial life directly. Fresh mine tailings are low in microbial life and plant- available nitrogen, whereas in the contaminated Austrian medieval samples, conditions have had time to adapt for more than 600 years. In the test substrates, supply with nutrient nitrogen was low, supply with nutrient phosphorus was low to adequate, and supply with potassium and sulfate was adequate. Effects of various additives on the plant yield mainly depend on the initial nutrient status. After harvest, the soils were parted in root soils and bulk soils to recognize possible differences. The lettuce plants were parted in leaves and roots. The solids were characterized by convential methods and aqua regia digestion, as well as by a Tessier-type sequential leaching procedure. The plant samples were digested with HNO3/HClO4. Basically, sample solutions were simultaneously read for 23 elements in ICP-OES in appropriate dilutions. Various treatments result in concentration shifts in root soil, bulk soil, plant roots and plant leaves. Interpretation is not easy, but physiologically active elements or contaminants are usually more involved.  相似文献   

18.
The authors investigated the effect of Bacillus mucilaginosus on weathering of phosphorite. Analysis of different proteins was of significance in exploring the molecular biological mechanism in the bacterial weathering process. The concrete methods are described as follows： Mineral powder was put into liquid culture medium and B. mucilaginosus was incubated in the medium. The control （group） had no mineral powder in the medium. The treatments and controls were cultured simultaneously under the same condition. In a few days, the supernatant was filtrated, the main cations （Ca^2＋, Mg^2＋, Na^＋, Mn^2＋, Al^3＋, Fe^3＋, K^＋） were measured by ICP-OES, and the contents of water soluble phosphorus （Pws） and silicon （Siws） were determined by colorimetry. The residual solid was weighed on the filter paper, followed by digestion with concentrated HNO3. The concentrations of the main cations and Pws, Siws in the digest liquid were measured by using the method mentioned above. After the supernatant was centrifuged, the precipitation was used to analyze the protein differences between the treatment groups and the control groups by 2-dimentional gel electrophoresis （2-DE）. The experimental results showed that apatite and quartz were partially weathered, but kaolinite was dissolved completely. The population of bacteria increased when mineral powder was added in the liquid medium. Software analysis and comparison of the 2-DE pictures of bacterial proteins revealed 1134 visible protein spots in the treatment group, and 729 visible protein spots in the control group. To compare the bacterial protein expression contents of the treatment group with those of the control group, there were 496 different protein spots, including 214 protein spots which indicated that the protein contents increased, 75 protein spots were indicative of a decrease, and 207 proteins were newly synthesized. It is proposed that the increased bacterial contents may be related to some protein expression and activation after the  相似文献   

19.
A simulating experiment was carried out on the interaction between natural precipitation and soil. The results demonstrated that the contents of heavy metals （V, Co, Cr, and Ni） released from soil into the solution under Earth＇s surface conditions are higher than the contents of those metals bonded to exchangeable species, which were extracted by sequential extraction procedure recommended by Tessier and others in 1979. It is demonstrated that the metals bonded to other 3 species （carbonate, Fe-Mn oxide, and organic matter） except those bonded to the exchangeable species in efficient speciation can be released under the Earth＇s surface conditions, when pH=4 in the reaction system, and the higher correlation coefficient indicated that the concentrations of heavy metals released from soil into the solution vary approximately with reaction time in terms of index regulations.  相似文献   

20.
Low molecular weight organic acids （LMWOAs） are important components of root exudates. They play an important role in immobilizing and remobilizing contaminants in rhizospheric soil. Effects of four LMWOAs on the sorption and desorption behavior of p-chlorophenol by yellow earth was studied in batch mode. The results showed that the previous application of LMWOAs to enhanced adsorption capacity of p-chlorophenol of the soil in the order of maleic acid〉malic acid〉oxalic acid〉citric acid. However, when LMWOAs were applied to soil where p-chlorophenol had been previously adsorbed, substantial p-chlorophenol was desorbed from soil by oxalic acid, whereas citric acid, malic acid and maleic acid didn＇t desorb as much p-chlorophenol from soil as deionized water.  相似文献   

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