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1.
The diversity of bacteria metabolizing nitriles of carbonic acids was studied in soils of the Perm region affected by human activities. Effective methods for selective isolation of cultures possessing the nitrile hydratase and nitrilase activities were developed. Most microorganisms capable of utilizing nitriles were Grampositive Nocardia-like bacteria of the genus Rhodococcus. Isolates with a detectable nitrilase activity were also represented by Gram-negative forms (Gram-negative aerobic/microaerophilic bacilli and cocci of the genera Pseudomonas, Azomonas, Azotobacter, and Acidovorax). Two enzyme systems for nitrile hydrolysis were found in 27% of cultures. The nitrile hydratase and nitrilase activities of the studied strains exceeded these enzymatic activities in bacteria isolated from native soils, which indicates that natural selection of saprophytic microflora occurs in chemically altered soils.  相似文献   

2.
The work presents the radioecological characterization of the new Brazilian uranium mining and milling site located in a semi-arid region of the country. The process characterization demonstrated that in heap leach plants most of the 226Ra remains in the leached ore. Despite the potential higher availability of radium isotopes in the soils of the studied region the lack of precipitation in that area reduces the leaching/mobilization of the radionuclides. High 226Ra and 228Ra concentrations were found in manioc while 210Pb was significant in pasture. It was suggested that a range from 10(-3) to 10(-1) may conveniently encompass most of the transfer factors (TF) values for soil/plant systems (i.e. involving different cultures, different soils and natural radionuclides). Impacts due to aerial transportation of aerosols and radon generated in the mining were proved to be minimal and restricted to an area not greater than 15 km2. Finally, uranium complexation by carbonates was shown to be the main mechanism responding for the elevated radionuclide concentration in groundwater.  相似文献   

3.
Information on the type and quantity of industrial pollutants from major land-based sources entering the marine environment through direct coastal discharges or indirectly through rivers, as well as on the present status of industrial waste management (treatment and disposal) practices, are provided for the West African region. Most of the data utilized in this analysis were collected by six UNIDO experts who visited the eighteen countries of the West African region during the period of January through August 1980. Industrial operations were visited and information was collected from the various ministries involved with industrial development and environmental protection. Estimates of the mass of pollutants discharged to the ocean were based upon production rates used in conjunction with actual measurements made by the industries located in the countries visited; studies reported in the literature; and an extrapolation of the U.S. Environmental Protection Agency Effluent Standards for various industrial sectors. The West African region was divided into five zones closely approximating the major currents of the Atlantic Ocean. The estimated pollution discharged by the industrial sector was calculated for each of the zones by adding the contribution from each country assigned to a zone.  相似文献   

4.
Radionuclides from past uranium mining in rivers of Portugal   总被引:2,自引:0,他引:2  
During several decades and until a few years ago, uranium mines were exploited in the Centre of Portugal and wastewaters from uranium ore milling facilities were discharged into river basins. To investigate enhancement of radioactivity in freshwater ecosystems, radionuclides of uranium and thorium series were measured in water, sediments, suspended matter, and fish samples from the rivers Vouga, D?o, Távora and Mondego. The results show that these rivers carry sediments with relatively high naturally occurring radioactivity, and display relatively high concentrations of radon dissolved in water, which is typical of a uranium rich region. Riverbed sediments show enhanced concentrations of radionuclides in the mid-section of the Mondego River, a sign of past wastewater discharges from mining and milling works at Urgeiri?a confirmed by the enhanced values of (238)U/(232)Th radionuclide ratios in sediments. Radionuclide concentrations in water, suspended matter and freshwater fish from that section of Mondego are also enhanced in comparison with concentrations measured in other rivers. Based on current radionuclide concentrations in fish, regular consumption of freshwater species by local populations would add 0.032 mSv a(-1) of dose equivalent (1%) to the average background radiation dose. Therefore, it is concluded that current levels of enhanced radioactivity do not pose a significant radiological risk either to aquatic fauna or to freshwater fish consumers.  相似文献   

5.
During the last 5 yr, the air of sewage treatment plants was examined bacteriologically under different climatic conditions. Methods of examination were sedimentation on nutrient agar, membrane filtration and the use of an impinger. At each sampling site wind velocity and humidity of air were measured. In addition to colony counts, the presence of fecal indicators (E. coli, Clostridia), Salmonella, non-agglutinable cholera vibrios and Pseudomonas aeruginosa was determined. The results were as follows: The formation of mist above the sewage in aeration tanks was preferably observed during the winter season. Correspondingly, the bacteriological results were less favourable in winter-time; trickling filters are also capable of spreading bacteria into ambient air; E. coli could be found up to a distance of 300 m downwind from the aeration tanks, Salmonella up to a distance of 10 m; higher wind velocity resulted in a higher number of positive findings, sunshine diminished it, covering of the aeration tanks clearly resulted in a lower number of positive findings, parallel examinations performed at other sampling sites far from sewage treatment plants, such as underground stations, shops, or sports facilities revealed that the bacterial level at such sites was much lower than in the air of sewage treatment plants. Quantitative studies (Salmonella was taken as an example) revealed that the dissemination by air was low in relation to the Salmonella content of the sewage itself, so that the infectious dose was hardly attained by direct ingestion. Nevertheless, hygienic measures, such as hand washing, use of protecting clothes and avoidance of contact with foods in the open air should be performed in sewage treatment plants so that the infectious dose also cannot be indirectly reached. Beyond this, the possibility cannot be ruled out that conditions are quite different for other pathogens having much lower infectious doses.  相似文献   

6.
The degradation of DDT in aqueous phase was studied by treating it with microflora present in activated sludge developed in bench-scale reactors and in vitro by incubating it with mixed liquor from the activated sludge and with the bacteria obtained after enrichment of the mixed liquor culture through repeated transfers with increasing doses of DDT in standard inorganic medium. It was observed that several strains of bacterial isolates as well as the mixed culture were able to degrade DDT with hardly any formation of the stable metabolites DDD or DDE. The activated sludge degraded DDT (1 to 55 mg/L) almost completely within 23 h, as only some of the effluent samples contained DDTs up to 0.03 mg/L. The bacteria belonged to the genera Bacillus, Micrococcus, Pseudomonas, and Flavobacterium. The mixed liquor and individual bacteria, when incubated with DDT in a mineral medium for 42 days under culture conditions which were static, brought about 50% to 74% and 44% to 69% degradation of DDT respectively. Under shaked conditions, these bacteria, when incubated up to 1 month with 50,200 and 500 mg/L DDT, showed 5.3% to 76.6% degradation of DDT, respectively. Traces of DDE and DDD were detected in a few samples. The microorganisms were able to utilise DDT as a source of carbon and hence can be used for biotreatment of DDT.  相似文献   

7.
This paper presents the results of an evaluation of excessive salt emissions from 16 hogged fuel boilers in Washington, Oregon, and Alaska. Logs transported or stored in sea water, absorb substantial amounts of salt which is noncombustible, and is emitted as a fine particulate when the hogged fuel is burned, contributing to opacity and particulate emissions. Control measures considered are fuel pretreatment, combustion modification, use of conventional particulate control devices (electrostatic precipitators, fabric filters, and wet scrubbers), and several novel particulate control devices.The best available control technology appears to be a mechanical collector-fabric filter combination; some electrostatic scrubber type devices have also shown excellent capability.  相似文献   

8.
Microorganisms capable of degrading monocyclic and polycyclic aromatic hydrocarbons and several chlorinated aromatic compounds were isolated from soils polluted with industrial waste from chemical plants. They were identified as representatives of the genera Pseudomonas, Flavobacterium, Alcaligenes, Rhodococcus, Microbacterium, Cellulomonas, Arthrobacter, and Brevibacterium. Among them, bacteria capable of utilizing xenobiotics in a wide range of ambient temperatures and pH and in the presence of high sodium chloride concentrations were revealed.  相似文献   

9.

Mining has become one of the main causes of increased heavy metal loading of river systems throughout the world. There is however an evident gap between assessments of soil contamination and metal release at the mined sites and estimates of river pollution. The present work focuses on Zaamar Goldfield, which is one of the largest placer gold mines in the world, located along the Tuul River, Mongolia, which ultimately drains into Lake Baikal, Russia. It combines field observations in the river basin with soil erosion modelling and aims at quantifying the contribution from natural erosion of metal-rich soil to observed increases in mass flows of metals along the Tuul River. Results show that the sediment delivery from the mining area to the Tuul River is considerably higher than the possible contribution from natural soil erosion. This is primarily due to excessive mining-related water use creating turbid wastewaters, disturbed filtering functions of deposition areas (natural sediment traps) close to the river and disturbances from infrastructures such as roads. Furthermore, relative to background levels, soils within Zaamar Goldfield contained elevated concentrations of As, Sr, Mn,V, Ni, Cu and Cr. The enhanced soil loss caused by mining-related activities can also explain observed, considerable increases in mass flows of metals in the Tuul River. The present example from Tuul River may provide useful new insights regarding the erosion and geomorphic evolution of mined areas, as well as the associated delivery of metals into stream networks.

  相似文献   

10.
Environment, Development and Sustainability - In this study, non-carcinogenic health risks of thallium in grapevine exposed to mine waters of an abandoned mining region in Turkey were evaluated....  相似文献   

11.
The release of radon gas and progeny from the mining and milling of uranium-bearing ores has long been recognised as a potential radiological health hazard. The standards for exposure to radon and progeny have decreased over time as the understanding of their health risk has improved. In recent years there has been debate on the long-term releases (10,000 years) of radon from uranium mining and milling sites, focusing on abandoned, operational and rehabilitated sites. The primary purpose has been estimates of the radiation exposure of both local and global populations. Although there has been an increasing number of radon release studies over recent years in the USA, Australia, Canada and elsewhere, a systematic evaluation of this work has yet to be published in the international literature. This paper presents a detailed compilation and analysis of Australian studies. In order to quantify radon sources, a review of data on uranium mining and milling wastes in Australia, as they influence radon releases, is presented. An extensive compilation of the available radon release data is then assembled for the various projects, including a comparison to predictions of radon behaviour where available. An analysis of cumulative radon releases is then developed and compared to the UNSCEAR approach. The implications for the various assessments of long-term releases of radon are discussed, including aspects such as the need for ongoing monitoring of rehabilitation at uranium mining and milling sites and life-cycle accounting.  相似文献   

12.
The present work presents the results of 137Cs concentration in seawater, fish and sediments samples collect in 11 sampling points, crossing the Brazilian Southeastern coastal region, from Vitória (ES) to Santos (SP), on a routine basis from 1997 to 2002. This monitoring program was carried out by the Instituto de Radioproteção e Dosimetria (IRD/CNEN/MCT), in cooperation with the Instituto de Estudos do Mar Almirante Paulo Moreira (IEAPM/Brazilian Navy), aiming at determining artificial radionuclides in marine samples. Additionally to the 137Cs results, 90Sr concentrations in fish samples from 1998 to 2002 are also reported.The 137Cs in seawater follows a lognormal distribution, with a geometric mean of 1.8 Bq m-3 and a geometric standard deviation of 1.4 (n=54), decay corrected to June/2002. For 137Cs levels in fish samples a geometric mean of 0.19 Bq kg−1 and a geometric standard deviation of 2.9 (n=39), decay corrected to June/2002, with a range of 0.03 to 1.7 Bq kg−1, were obtained. Based on the 137Cs mean concentration in fish as well as in seawater, a transfer factor of 1 × 102 was calculated, which is quite in agreement with the recommended value found in the Safety Report Serie 19.  相似文献   

13.
We describe a three step process for the removal of uranium (U) from dilute waste waters. Step one involves the sequestration of U on, in, and around aquatic plants such as algae. Cell wall ligands efficiently remove U(VI) from waste water. Growing algae continuously renew the cellular surface area. Step 2 is the removal of U-algal particulates from the water column to the sediments. Step 3 involves reducing U(VI) to U(IV) and transforming the ions into stable precipitates in the sediments. The algal cells provide organic carbon and other nutrients to heterotrophic microbial consortia to maintain the low E(H), within which the U is transformed. Among the microorganisms, algae are of predominant interest for the ecological engineer because of their ability to sequester U and because some algae can live under many extreme environments, often in abundance. Algae grow in a wide spectrum of water qualities, from alkaline environments (Chara, Nitella) to acidic mine drainage waste waters (Mougeotia, Ulothrix). If they could be induced to grow in waste waters, they would provide a simple, long-term means to remove U and other radionuclides from U mining effluents. This paper reviews the literature on algal and microbial adsorption, reduction, and transformation of U in waste streams, wetlands, lakes and oceans.  相似文献   

14.
To evaluate the environmental impacts from large scale mercury mining (LSMM) and artisanal mercury mining (AMM), total mercury (THg) and methyl mercury (MeHg) were determined in mine waste, ambient air, stream water and soil samples collected from Wuchuan mercury (Hg) mining area, Guizhou, Southwestern China. Mine wastes from both LSMM and AMM contained high THg concentrations, which are important Hg contamination sources to the local environment. Total gaseous mercury (TGM) concentrations in the ambient air near AMM furnaces were highly elevated, which indicated that AMM retorting is a major source of Hg emission. THg concentrations in the stream water varied from 43 to 2100 ng/L, where the elevated values were mainly found in the vicinity of AMM and mine waste heaps of LSMM. Surface soils were seriously contaminated with Hg, and land using types and organic matter played an important role in accumulation and transportation of Hg in soil. The results indicated heavy Hg contaminations in the study area, which were resulted from both LSMM and AMM. The areas impacted by LSMM were concentrated in the historical mining and smelting facilities, while Hg pollution resulted from AMM can be distributed anywhere in the Hg mining area.  相似文献   

15.
To evaluate the consequences of irradiation on the vegetation of the Chernobyl region, gene expression was compared in morphologically normal and dwarf needles from the same Pinus sylvestris trees in a region where the absorbed dose was 3-5 Gy. To compare the levels of gene expression, arrays consisting of 373 Pinus taeda cDNAs were hybridized with labeled cDNA derived from normal and dwarf needles of P. sylvestris. Twelve genes were significantly (P<0.01) up- or down-regulated between normal and dwarf needles for all five trees taken together. Five of these, related to stress or development, were up- or down-regulated 1.25-1.7-fold in the dwarf needles. There were no significant differences in (137)Cs content in the normal and dwarf needles, or in elongation growth rate of seedlings raised under controlled conditions from seed derived from trees in the region that had received a radiation dose over the range 2-12 Gy.  相似文献   

16.
基于社会生态系统视角的长三角地级城市韧性度评价   总被引:2,自引:0,他引:2  
为提升城市应对重大冲击和慢性压力的能力,提高城市的抗打击能力与恢复能力,以及城市对抗不确定风险的韧性程度,本文结合现实背景,以城市社会生态系统的视角,对2014年长三角地区16个地级城市韧性进行实证分析。采用GIS的空间分析和叠加功能方法,从生态环境、市政设施、经济和社会发展4个方面选取24个具体指标,对长三角地区16个地级城市韧性程度及其空间状态做出评价,并确定测度标准值。首先对构成城市韧性的4个因子:生态、市政设施工程、经济以及社会发展进行分析和数字化,得出各因子对城市韧性影响程度的栅格图层;其次对图层进行空间叠加,再得到长三角地区地级城市韧性度评价图。评价结果表明:(1)长三角地级城市韧性呈现"级差化"分布状态,总体呈现出中等韧性状态;(2)长三角地级城市韧性空间分异特征显著,其北翼城市比南翼城市韧性程度较高;(3)长三角地级城市经济、生态韧性在空间分布上相对集中,趋向协调均衡发展。通过城市韧性度分析,认为评价结果基本符合近年来长三角地区城市韧性发展的整体状况,可以在一定程度上增强城市社会生态系统对外界风险的适应能力,并在今后的城市发展调适过程中更具韧性,从而对不同时空尺度的城市韧性状态评价提供一种思路。  相似文献   

17.
The distributions of 238Pu and 239+240Pu in surface soils from the Piemonte region were measured and the main factors influencing Pu concentrations investigated. Rainfall, altitude and the concentration of organic matter play an important role, while other soil parameters (pedology, lithology and geomorphology) are of lesser significance. Contour maps of the surface soil concentrations of 238Pu and 239+240Pu are reported.  相似文献   

18.
The presence of erm genes was investigated among macrolide-resistant Gram-positive bacteria isolated from soil samples collected from four Danish farms that had been treated with animal waste. Soil samples were collected before, a few days after spread and 1 1/2 months and 5 months later. In 33% (9/27) of these isolates, an erm gene was detected using PCR. Eight isolates were positive for erm(B) and one isolate was positive for erm(C). No isolates contained erm(A), erm(D) or erm(F). The positive isolates were identified to genus level. Two erm(B) positive isolates were identified as Enterococcus spp., and the erm(C)-positive isolate as a Streptococcus spp., probably indicating survival from animal waste. The remaining six erm(B) positive isolates all belonged to the Bacillus cereus group. The erm(B) gene has not previously been identified in B. cereus but is frequently found among enterococci. This result could indicate horizontal transfer from bacteria of animal origin to indigenous soil bacteria.  相似文献   

19.
The hunting of wild animals remains a common activity in various parts of the world, especially in rural communities with poor socioeconomic conditions. To investigate patterns of mammal hunting, this study adopted a rural community located in semiarid Brazil as a model to test whether variables such as perceived abundance, activity period (day or night) and animal biomass could influence the consumption potential of mammal taxa. For this study, a checklist/interview technique using 32 photographs of mammals recorded in the region and two photographs of species that did not occur in the region, which acted as “control” species, was used, in addition to other visual stimuli and free lists. All species presented in the photographs, with the exception of the “control” species, were recognized as occurring in the region. Fourteen species were cited as being those most hunted locally. The species cited as most hunted had an average perceived abundance higher than the group of the least-hunted species. However, there was no significant relationship between hunting of a species and its locally perceived abundance. No significant difference in hunting pressure between diurnal and nocturnal species was found, nor was a relationship between animal biomass and hunting pressure observed. Our findings suggest that perceived abundance is an important factor for choosing a resource fauna, but other factors such as intended use, meat flavor and vulnerability to hunting, among others, may influence the potential use of a species.  相似文献   

20.
Radium and heavy metal contaminated tailings and scales resulting from Polish hard coal mining were investigated for their mobilisation potential by using leaching methods. The main focus is set on a three-step extraction procedure proposed by BCR (Bureau Communautaire de Référence, now Standards Measurements and Testing Programme) of the European Union, which was used for investigating the availability of radium isotopes. In addition, the results of a Polish extraction procedure for the heavy metals' water solubility are presented for rough comparison. After a special treatment, the BCR-reagents were measured by gamma-spectrometry to define their radium activity concentrations; the heavy metal content in the water soluble fractions was determined by ICP-AES. The samples were collected at two different sites influenced by the discharge of pit water from hard coal mining. The tailings were taken from a former tailing pond, which now is no longer in use, but the settled material is still present. At another abandoned and meanwhile flooded tailing pond, the scales were scraped from the inside of a discharge tube. The results obtained show that there is different leaching behaviour between the radium isotopes. The tailings being characterised by surface adsorbed radium provide up to 25% of the initial (226)Ra content, (228)Ra is altogether leached up to 15%. The scales comprise stable radiobaryte (Ba[Ra]SO(4)) and can be considered as being unable to provide radium isotopes, since no trace of radium dissolution was observed. The leaching behaviour of heavy metals is similar to that of radium. Mn, Ni and Zn are dissolved by water from the tailings; the scales do not provide any.  相似文献   

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