[Petroleum pollution and microbial community structure in the soil of Liaohe Oilfield.] / è¾½æ²³æ²¹ç”°åœŸå£¤çŸ³æ²¹æ±¡æŸ“åŠå ¶å¾®ç”Ÿç‰©ç¾¤è½ç‰¹å¾.

We analyzed the soil physico-chemcial properties, microbial community structure, petroleum hydrocarbon contents and components in soil samples from the well sites of Shuguang, Huanxi-ling and Jinzhou oil exploitation sites in Liaohe Oilfield, with uncontaminated paddy soil as a control. The results showed that: 1) The soil around all the three oil exploitation sites were seriously polluted by petroleum with certain differences in the petroleum hydrocarbon contents and components. The average content of petroleum hydrocarbon in the soil of Shuguang and Huanxiling oil exploitation sites was two times higher than that of Jinzhou oil exploitation site. The content of resins and asphaltenes in the soil of Shuguang oil exploitation site was the highest, while the soils of Huan-xiling and Jinzhou oil exploitation sites had the highest alkane content, which accounting for more than 40% in all the sites. 2)Compared with the paddy soil, the microbial OTU numbers, Chao1 and Shannon indices in the soil of Jinzhou oil exploitation site increased. The dominant phyla and genera were similar in the soil of all oil exploitation sites but with large differences in abundance. The soil in Jinzhou oil exploitation site had higher abundance of Mycobacterium and Pseudomonas, while Sphingomonas and Nocardioides, Massilia in the soil of Shuguang oil exploitation site, and Lysobacter, Thiobacillus and Pseudomonas in the soil of Huanxiling oil exploitation site. 3) The abundances of Sphingomonas, Nocardioides, Thiobacillus, Massilia, Pseudomonas and the contents of total petroleum hydrocarbons, total organic carbon and resins and asphaltenes were significantly positively correlated, while Mycobacterium, Lysobacter and Pseudomonas were significantly positively correlated with the contents of total nitrogen and total phosphorus. This study systematically analyzed the petroleum hydrocarbon, physico-chemcial properties and microbial communities in the soil of different oil exploitation sites, and revealed the specific dominant bacterial genera and microbial communities in the soil of Liaohe Oilfield. Our results provided a theoretical basis for functional bacterium screening and microbial community construction in the remediation process of petroleum contaminated soil in Liaohe Oilfield, and a reference for efficient degradation bacteria screening in other oilfields.

[Distribution characteristics and model establishment of microorganisms in electrokinetic remediation of organic contaminated soil.] / 有机污染土壤电动修复过程中微生物的分布特征及模型构建.

Soil microorganisms would reproduce rapidly and migrate directionally under the applied electric field. In this study, tetradecane-degrading bacteria were added at different locations in soil, and 1 V·cm-1 unidirectional DC electric field was applied to investigate the migration, distribution, and degradation characteristics of target bacteria in soil. The results showed that microorga-nisms migrated to the cathode and anode by electrodialysis and electrophoresis, respectively. The number of microorganisms migrated by electrodialysis was 3.5 times of that by electrophoresis. The application of electric field could make the soil environment spatially heterogeneous to affect the growth of microorganisms. The average number of soil microorganisms under electric field was 1.16×108 CFU·g-1(6 days), which was 2.3 times of that without electric field. S2 to S4 were the efficient growth areas of microorganisms, with the average number after 30-day electric treatment being 2.8-3.5 times of that on the anode and cathode, and 2.1 times of that in the control. There was a significant positive correlation between the tetradecane degradation rate and the number of microorganisms (r=0.895, P＜0.05). The optimal tetradecane degradation region was near the cathode (S4), where its degradation rate reached 94.6%. Based on these results, a model modified by environmental factors was established to simulate the spatial distribution of microorganisms under the combined effect of electrokinetic stimulation and transportation. According to the model, the number distribution of microorganisms could be deduced when exogenous bacteria were added in a fixed section. The results provide a theoretical basis for the efficient import of exogenous functional bacteria in electrokinetic-bioremediation of organic contaminated soil.

A Semi-Empirical Deflection-Based Method for Crack Width Prediction in Accelerated Construction of Steel Fibrous High-Performance Composite Small Box Girder.

Accelerated construction in the form of steel⁻concrete composite beams is among the most efficient methods to construct highway bridges. One of the main problems with this type of composite structures, which has not yet been fully clarified in the case of continuous beam, is the crack zone initiation that gradually expands through the beam width. In the current study, a semi-empirical model was proposed to predict the size of cracks in terms of small box girder deflection and intensity of load applied on the structure. To this end, a set of steel⁻concrete composite small box girders were constructed by the use of steel fibrous concrete and experimentally tested under different caseloads. The results were then used to create a dataset of the box girder response in terms of beam deflection and crack width. The obtained dataset was then utilized to develop a simplified formula providing the maximum width of cracks. The results showed that the cracks initiated in the hogging moment region when the load exceeded 80 kN. Additionally, it was observed that the maximum cracked zone occurred in the center of the beam due to the maximum negative moment. Moreover, the crack width of the box girder at different loading cases was compared with the test results obtained from the literature. A good agreement has been found between the proposed model and experiment results.

[Fluorine emission list of China's key industries and soil fluorine concentration estimation.] / æˆ‘å›½é‡ç‚¹æ°Ÿæ±¡æŸ“è¡Œä¸šæŽ’æ”¾æ¸ å•ä¸ŽåœŸå£¤æ°Ÿæµ“åº¦ä¼°ç®—.

Industry-induced fluorine emissions and high background values of fluorine in soil lead to serious fluorine pollution in some regions of China, posing a serious threat to ecological security and human health. Based on the production capacity of China's key industries contributing to fluorine emission, we estimated the fluorine emissions of key industries and built a fluorine emission list in China. Based on data integration and fusion, the soil fluorine background value, fluorine geochemical distribution and soil fluorine concentration distribution in China were analyzed. Then, the causes and control of fluorine pollution in typical areas were analyzed. The results showed that productions of steel, phosphorus fertilizers and electrolytic aluminum were the key industries for fluorine emissions in China. The highest fluorine emission was from the application of phosphorus fertilizers. Due to the huge area of P application, its contribution to soil fluorine concentration was negligible. Electrolytic aluminum production resulted in a high intensity of fluorine emission. A high amount of fluorine was discharged with steel industry production, with low emission intensity. In most parts of China, the soil fluorine background value is low and the environmental capacity is large. In some areas of China, however, fluorine pollution is serious, mainly due to industrial fluorine emissions and high background values of fluorine in soil. These regions should take corresponding prevention and control measures.

[Fluorine speciation in soil and the remediation of fluorine contaminated soil]. / 土壤氟形态与氟污染土壤修复.

In China, fluoride pollution in soil is severe and poses a serious threat to human health and ecological security. However, how to control fluorine-contaminated soil has not received widespread attention. Here, we summarized fluorine speciation in soil and its main chemical reactions in water-soil system and reviewed the research progress on the remediation of fluorine-contaminated soils. Then, we proposed the focus of future research on fluorine-contaminated soil remediation. The aim of this review was providing the reference for the remediation of fluoride-contaminated soil. There are five forms of fluorine in soils, with the proportion of residual fluorine being over 90%. The reactions of fluorine in the soil solution mainly include precipitation-dissolution, complexation-dissociation, and adsorption-desorption. At present, the remediation technology of fluorine contaminated soil mainly focused on chemo-immobilization, chemical leaching, electrokinetic remediation, and phytoremediation. Clarifying the combined forms of fluorine in soil, screening functional microorga-nisms and plants, developing the combined remediation technology will be the focus of future research. Ultimately, on site fluorine-contaminated soil remediation could be implemented.

[Environmental and geochemical behaviors of fluorine and its impacts on ecological environment]. / æ°Ÿçš„çŽ¯å¢ƒåœ°çƒåŒ–å­¦è¡Œä¸ºåŠå ¶å¯¹ç”Ÿæ€çŽ¯å¢ƒçš„å½±å“.

In past decades, fluorine exposure of plants and human caused by regional geochemical anomalies of fluorine or environmental pollution has received widespread concerns. Many in-depth researches have been conducted on the geochemical behavior of fluorine in different environmental media, but with disputes and uncertainties. We reviewed the research advances on geochemical behaviors of fluorine in the atmosphere, water and soil, including source, quantity, existence form, migration, transformation, and controlling factors. The observation of correlation between geochemical behaviors of fluorine and plant and human fluoride exposure was also reviewed. Moreover, we proposed that the future research on environmental geochemical behaviors of fluorine should give priority to particular directions.

Novel Bacillus cereus strain from electrokinetically remediated saline soil towards the remediation of crude oil.

A new strain SWH-15 was successfully isolated after initial electrokinetic remediation experiment using the same saline soil sampled from Shengli Oilfield, China. Four methods (morphological and biochemical characteristics, whole-cell fatty acid methyl esters (FAMEs) analysis, 16S rRNA sequence analysis and DNA G + C content and DNA-DNA hybridization analysis) were used to identify the taxonomic status of SWH-15 and confirmed that SWH-15 was a novel species of the Bacillus (B.) cereus group. Then, we assessed the degrading ability of the novel strain SWH-15 to crude oil through a microcosm experiment with four treatments, including control (CK), bioremediation using SWH-15 (Bio), electrokinetic remediation (EK), and combined bioremediation and electrokinetic remediation (Bio + EK). The results showed that the Bio + EK combined remediation treatment was more effective than the CK, Bio, and EK treatments in degrading crude oil contaminants. Bioaugmentation, by addition of the strain SWH-15 had synergistic effect with EK in Bio + EK treatment. Bacterial community analysis showed that electrokinetic remediation alone significantly altered the bacterial community of the saline soil. The addition of the strain SWH-15 alone had a weak effect on the bacterial community. However, the strain SWH-15 boosted the growth of other bacterial species in the metabolic network and weakened the impact of electrical field on the whole bacterial community structure in the Bio + EK treatment.

[Draft of soil environmental function regionalization of China]. / 中国土壤环境功能区划方案.

Soil environmental function regionalization is of significance for soil environmental classification management in China. In this paper, we discussed the broad and narrow concept of soil environmental function and its corresponding attributes. Based on the constraint analysis on the soil environmental quality to function, relationship between soil environmental function and quality was illustrated. Compared with different methods and indices of soil environmental function regionalization, we established the index system of soil environmental function regionalization according to the soil environmental suitability and function. The proposed draft of soil environmental function regionalization included four first-class function types, 10 second-class function types, and 75 soil environmental functional areas. According to the differences among those functional areas, we proposed corresponding management countermeasures. The results provided scientific basis for the control and prevention of soil pollution and the control of regional risk in China.

[A process of aquatic ecological function regionalization: The dual tree framework and conceptual model]. / 水生态功能区划流程:åŒå ³ç³»æ ‘æ¡†æž¶ä¸Žæ¦‚å¿µæ¨¡åž‹.

Aquatic ecological regionalization and aquatic ecological function regionalization are the basis of water environmental management of a river basin and rational utilization of an aquatic ecosystem, and have been studied in China for more than ten years. Regarding the common problems in this field, the relationship between aquatic ecological regionalization and aquatic ecological function regionalization was discussed in this study by systematic analysis of the aquatic ecological zoning and the types of aquatic ecological function. Based on the dual tree structure, we put forward the RFCH process and the diamond conceptual model. Taking Liaohe River basin as an example and referring to the results of existing regionalization studies, we classified the aquatic ecological function regions based on three-class aquatic ecological regionalization. This study provided a process framework for aquatic ecological function regionalization of a river basin.

[Rapid screening and construction of high-efficient petroleum-degrading microflora through enzyme activity assay]. / é‡‡ç”¨é ¶æ¶²æ´»æ€§æµ‹å®šæ³•å¿«é€Ÿç­›é€‰åŠæž„å»ºçŸ³æ²¹çƒƒé«˜æ•ˆé™è§£èŒç³».

It is of great practical significance to rapidly screen the mixed microbial flora for degradation of complex organic pollutants. It was the first time to rapidly calibrate the petroleum hydrocarbon degradation ability of highly efficient degrading microflora by measuring enzyme activity analyzed by the MicroRespTM technology. The results were validated by the traditional shaking culture. According to the activity analysis of exoenzymes, endoenzymes and mixed enzymes, the degradation abilities of microflora and enzymes (including exoenzymes, endoenzymes and mixed enzymes) on petroleum hydrocarbon was investigated. The results showed that the enzyme activity assay had perfect sensitivity and high-throughput for rapidly detecting the degradation ability of the petroleum hydrocarbon. The test period was 12 h which was 10 times shorter than shaking culture for 120 microflora combinations. The maximum degradation extent of the petroleum hydrocarbon by microflora reached (56.1±1.6)%. It was concluded that the method of enzyme activity assay was high-efficient and high-throughput screening, which could be used in the construction of petroleum-degrading microflora.

[Risk assessment of cadmium in rice in Xiangtan, Hunan, China based on Bayesian method]. / 基于贝叶斯方法的湖南湘潭稻米Cdè¶ æ ‡é£Žé™©è¯„ä¼°.

In this study, a total of 73 groups of paddy soil and rice samples were collected from 3 counties of Xiangtan City, Hunan Province, which were Xiangtan, Yuhu, and Xiangxiang, respectively. The total content of Cd in soil and rice samples was determined, the available Cd in soil samples also was measured, and the correlation analysis was conducted among them, respectively. According to the prior probability and data feature, we proposed to use the Bayesian method to eva-luate the risk of Cd content exceeding criterion in rice and construct the risk assessment model. The results indicated that, the average soil Cd content, soil available Cd content and the rice Cd content in the study area were (0.891±0.638) mg·kg-1, (0.791±0.582) mg·kg-1 and (0.376±0.395) mg·kg-1, respectively, and the exceeding standard rate of Cd content in soil and rice reached 89.0% and 52.1%. The rice Cd content was significantly correlated with the available Cd content and total Cd content in soil in Xiangtan and Yuhu. A better correlation was presented between the soil available Cd content and rice Cd content. The rice Cd content in Xiangxiang had no correlation with total Cd content and available Cd content in soil. When the total Cd content and available Cd content were selected as the variables of Bayesian model, the deviations between the predicted exceeding probability of Cd in rice and the true exceeding standard rate were 6.6% and 3.9%, respectively, which proved the Bayesian risk assessment model was reliable. Selecting the available Cd content as the model variable, the predicted result was closer to the true value.

Effects of different remediation treatments on crude oil contaminated saline soil.

Remediation of the petroleum contaminated soil is essential to maintain the sustainable development of soil ecosystem. Bioremediation using microorganisms and plants is a promising method for the degradation of crude oil contaminants. The effects of different remediation treatments, including nitrogen addition, Suaeda salsa planting, and arbuscular mycorrhiza (AM) fungi inoculation individually or combined, on crude oil contaminated saline soil were assessed using a microcosm experiment. The results showed that different remediation treatments significantly affected the physicochemical properties, oil contaminant degradation and bacterial community structure of the oil contaminated saline soil. Nitrogen addition stimulated the degradation of total petroleum hydrocarbon significantly at the initial 30d of remediation. Coupling of different remediation techniques was more effective in degrading crude oil contaminants. Applications of nitrogen, AM fungi and their combination enhanced the phytoremediation efficiency of S. salsa significantly. The main bacterial community composition in the crude oil contaminated saline soil shifted with the remediation processes. γ-Proteobacteria, ß-Proteobacteria, and Actinobacteria were the pioneer oil-degraders at the initial stage, and Firmicutes were considered to be able to degrade the recalcitrant components at the later stage.

[Differential geometry expression and analysis of regionalized variables of typical pollutants concentration in terrestrial environment].

Based on the basic concepts of differential geometry in analyzing environmental data and establishing related models, the methodology for differential geometry expression and analysis of pollutants concentration in terrestrial environment was presented. As a kind of regionalized variables, the spatial distribution pattern of the pollutants concentration was transformed into 3-dimension form, and fitted with conicoid. This approach made it possible to analyze the quantitative relationships between the regionalized variables and their spatial structural attributes. For illustration purpose, several sorts of typical space fabrics, such as convexity, concavity, ridge, ravine, saddle, and slope, were calculated and characterized. It was suggested that this approach was feasible for analyzing the regionalized variables of pollutants concentration in terrestrial environment.

[Revaluation of soil heavy metals pollution in Zhangshi irrigation area of Shenyang and analysis of Cd forms in soil].

This paper revaluated the situation of cadmium (Cd) pollution in rice field soils of Zhangshi irrigation area in Shenyang. The results indicated that the soil Cd pollution of test area was still quite serious. The Cd content in brown rice samples ranged from 0.435 to 0.855 mg x kg(-1), which exceeded the national criteria for food sanitation in China, and increased by 335%-755% compared with that 20 years ago. Brown rice Cd had a significant negative correlation with soil pH, and a positive correlation with soil available Cd. The decrease of soil pH induced more soil Cd transformed into available Cd which occupied 22.8%-52.0% of the total Cd and was easy to be absorbed by rice plant, inducing the Cd in brown rice exceeded national criteria. The pollutant Cd could transfer along with surface runoff, ground water and flying dust, making the pollution extend gradually.

Investigation on Fe, Mn, Zn, Cu, Pb and Cd fractions in the natural surface coating samples and surficial sediments in the Songhua River, China.

Natural surface coating samples (NSCSs) from the surface of shingles and surficial sediments (SSs) in the Songhua River, China were employed to investigate the relationship between NSCSs and SSs in fractions of heavy metals (Fe, Mn, Zn, Cu, Pb, and Cd) using the modified sequential extraction procedure (MSEP). The results show that the differences between NSCSs and SSs in Fe fractions were insignificant and Fe was dominantly present as residual phase (76.22% for NSCSs and 80.88% for SSs) and Fe-oxides phase (20.33% for NSCSs and 16.15% for SSs). Significant variation of Mn distribution patterns between NSCSs and SSs was observed with Mn in NSCSs mainly present in Mn-oxides phase (48.27%) and that in SSs present as residual phase (45.44%). Zn, Cu, Pb and Cd were found dominantly in residual fractions (>48%), and next in solid oxides/hydroxides for Zn, Pb and Cd and in easily oxidizable solids/compounds form for Cu, respectively. The heavy metal distribution patterns implied that Fe/Mn oxides both in NSCSs and SSs were more important sinks for binding and adsorption of Zn, Pb and Cd than organic matter (OM), and inversely, higher affinity of Cu to OM than Fe/Mn oxides in NSCSs and SSs was obtained. Meanwhile, it was found that the distributions of heavy metals in NSCSs and SSs were similar to each other and the pseudo-total concentrations of Zn, Cu, Pb and Cd in NSCSs were greater than those in SSs, highlighting the more importance for NSCSs than SSs in controlling behaviours of heavy metals in aquatic environments.

Scavenging of Cd through Fe/Mn oxides within natural surface coatings.

The dynamics of Cd scavenging from solutions by Fe/Mn oxides in natural surface coatings (NSCs) was investigated under laboratory conditions. Selective extraction methods were employed to estimate the contributions of Fe/Mn oxides, where hydroxylamine hydrochloride (0.01 mol/L NH2OH x HCl + 0.01 mol/L HNO3), sodium dithionite (0.4 mol/L Na2S2O4) and nitric acid (10% HNO3) were used as extraction reagents. The Cd scavenging was accomplished with developing periods of the NSCs (totally 21 data sets). The resulting process dynamics fitted well to the Elovich equation, demonstrating that the amount of Cd scavenged was proportional to the increments of Fe/Mn oxides that were accumulated in the NSCs. The amount of Cd bound to Fe oxides (M,,) and Mn oxides (MCdMn could be quantified by solving two equations based on the properties of two extraction reagents. The amount of Cd scavenged by Fe/Mn oxides could also be estimated using MCdFe and MCdMn, divided by the total amounts of Fe and Mn oxides in the NSCs, respectively. The results indicated that the Cd scavenging by Fe/Mn oxides was dominated by Fe oxides, with less roles attributed to Mn oxides. The estimated levels of Cd scavenging through Fe and Mn oxides agreed well with those predicted through additive-adsorption and linear-regression models.

Impact of anions on the heavy metals release from marine sediments.

Marine sediments from Lianshan Bay in Huludao, China, were studied in laboratory. A series of simulated experiments were carried out to investigate the influences of three kinds of anions Cl-, SO42- and HCO3 on the release of Cd, Pb, Cu and Zn from the sediments. The results showed that the sequences about the impact of the three anions were Cl- >HCO3 > SO42. The release potential of heavy metals in the presence of each anions was in the following order: Cd>>Cu>Zn approximately equal to Pb. The correlations were positive between Cl content and the quantity of Cd released from the marine sediment, whereas there was no significant relationship between Cl-content and amount of Cu and Zn released. For SO42- and HCO3-, the release of the heavy metals from marine sediments was not obvious.

Selective extraction and separation of Fe, Mn oxides and organic materials in river surficial sediments.

In order to investigate the adsorption mechanism of trace metals to surficial sediments (SSs), a selective extraction procedure was improved in the present work. The selective extraction procedure has been proved to selectively remove and separate Fe, Mn oxides and organic materials (OMs) in the non-residual fraction from the SSs collected in Songhua River, China. After screening different kinds of conventional extractants of Fe and Mn oxides and OMs used for separation of heavy metals in the soils and sediments, NH2OH x HC1 (0.1 mol/L) + HNO3 (0.1 mol/L), (NH4)2C204 (0.2 mol/L) + H2C2O4 (pH 3.0), and 30% of H2O2 were respectively applied to selectively extract Mn oxides, Fe/Mn oxides and OMs. After the extraction treatments, the target components were removed with extraction efficiencies between 86.09% -93.36% for the hydroxylamine hydrochloride treatment, 80.63% -101.09% for the oxalate solution extraction, and 94.76%-102.83% for the hydrogen peroxide digestion, respectively. The results indicate that this selective extraction technology was effective for the extraction and separation of Fe, Mn oxides and OMs in the SSs, and important for further mechanism study of trace metal adsorption onto SSs.