[Effects of Modified Biochar-Supported Zero-Valent Iron on the Removal of Trichloroethylene and Responses of Microbial Community in Soil].

Trichloroethylene is a typical organic contaminant that has widely existed in industry sites and groundwater. Biochar-supported zero-valent iron material has been used to remove trichloroethylene in groundwater; however, it could affect the microbial communities in aquifer soil, leading to changes in the environmental behavior of trichloroethylene. In this study, biochar was prepared under oxygen-limited conditions and modified by NaOH and HNO3 agents. Then, a modified biochar-supported zero-valent iron composite (BC composites) was synthesized using ball milling technology. The effects of BC composites on the removal of trichloroethylene and the responses of the microbial community were investigated under the condition of simulated aquifer soil. The results showed that the specific surface areas of BC composites were increased after the modification with NaOH. The highest removal rate of trichloroethylene was observed in the BC_2 treatment, up to 90.01%. Except in the BC_1 treatment, the diversity and abundance of soil microorganisms were increased, and the microbial community structure was changed after the addition of different BC composites, in which Bacillus, Thiobacillus, and Pseudomonas might have been the potential degrading bacteria of trichloroethylene. The abundance of Thiobacillus and Pseudomonas increased under the BC_2 treatment, which was favorable to the removal of trichloroethylene. The stabilization of the microbial community structure was probably maintained by Nocardioideas, Thermincola, Lysobacter, Gemmatimonas, Microvirga, and Pseudomonas. According to the predictive analysis of microbial metabolic pathways, the abundance of xenobiotics biodegradation and metabolism genes and the folding, sorting, and degradation of genes were the highest under the BC_2 treatment. Thus, the NaOH-modified BC composite could prompt the removal of trichloroethylene in simulated aquifer soil, probably due to the increase in the abundance of soil-degrading bacteria and the expression of degradation genes, demonstrating that the NaOH-modified BC composite could be used for the remediation of the organic-contaminated industry sites as a new composite material.

[Correlation Between the Diversity Characteristics of Groundwater Bacterial Community and Environmental Factors in Typical Industrial Areas].

In order to investigate the composition and diversity of groundwater bacterial communities in typical industrial areas in Shanghai, the Illumina MiSeq high-throughput technology was adopted to explore the correlation and response mechanism of groundwater bacterial communities and environmental factors in typical industries, combined with the analysis of groundwater tri-nitrogen, heavy metals, organic matter, and other indicators. The results showed that the ammonia nitrogen in the groundwater of the petrochemical industry was 64.49%, 32.46%, and 113.91% higher than that of the textile industry, metal products industry, and other industries (P<0.05), respectively. The main detectable indicators of organic matter were total petroleum hydrocarbons (TPH) and volatile phenol. The mass concentration of volatile phenol in groundwater of the petrochemical industry was significantly higher than that of the textile industry, metal products industry, and other industries (P<0.05). The mass concentration of arsenic in the metal products industry was 49.26% and 50.59% higher than that in the petrochemical industry and other industries (P<0.05), respectively. Chloride, manganese, sulfate, etc., were significantly different in different industries (P<0.05). The Shannon index of groundwater in the textile industry was the highest at 3.14, whereas the Shannon index and Ace index of the groundwater in the metal products industry were as low as at 2.42 and 960.46, respectively. The dominant bacterial phylum in groundwater in the industrial area was Proteobacteria, accounting for 80.05%-86.18%. Arsenic, mercury, TPH, etc. were the main influencing factors in groundwater in industrial areas, whereas the nitrifying bacteria, denitrifying bacteria, and organic matter-degrading bacteria were mostly related to groundwater environmental factors. The results of this study can provide theoretical support for groundwater pollution risk management and microbial remediation in petrochemical and metal product industrial areas.

[Content and Ecological Risks of Heavy Metals in Soil with Different Land Uses in a Rapidly Urbanizing Area].

Taking the Minhang District of Shanghai as a typical rapidly urbanizing area, and based on 595 soil samples from 36 plots, the content of eight heavy metals in soils from five different land uses were analyzed. The ecological risk was evaluated using the Nemerow composite index and the potential ecological risk index. The results showed that the variation coefficients of the heavy metals Zn and Cd were highest, and were notably affected by human activities. The content of heavy metals in industrial land soil was relatively high compared to residential land and cultivated land soils, and heavy metal content was lowest in public management and service land soil. The Nemerow composite index of Zn and Cd was high, corresponding to severe and moderate levels of pollution, respectively. The other heavy metals were found at warning or light levels of pollution. The potential ecological risks posed by heavy metals in the soils from different land uses, in descending order, were heavy-metal-related industry land > non-heavy-metal-related industry land≈residential land > cultivated land≈public management and service land. Industrial land had a greater risk of heavy metal pollution due to industrial operations, complex historical production, and widely variable levels of management. Heavy metal accumulation also tended to occur in residential land and cultivated land soils. Therefore, the prevention of soil heavy metal pollution in association with different land uses, and the control of associated risks during redevelopment, are key challenges in rapidly urbanizing area.

[Distribution Characteristics and Source Apportionment of Polycyclic Aromatic Hydrocarbons in Atmospheric Deposition in Areas Adjacent to a Large Petrochemical Enterprise].

In order to explore the influence of polycyclic aromatic hydrocarbons (PAHs) emissions by petrochemical enterprises on the surrounding environment, atmospheric deposition samples of the PAHs were collected in the industrial and residential areas adjacent to a petrochemical enterprise from March 2017 to February 2018. Deposition fluxes and the composition of PAHs were studied. The source of PAHs was analyzed by a positive matrix factor (PMF) model. The results showed that the deposition fluxes of Σ15 PAHs ranged from 549 ng·(m2·d)-1 to 18845 ng·(m2·d)-1, with an average of 2712 ng·(m2·d)-1. The flux of Σ15 PAHs in the industrial area was 1.36 times greater than that in the residential area. The deposition fluxes of PAHs in winter and spring were higher than those in summer and autumn. The deposition flux was highest in January in the industrial area and lowest in October in the residential area. Phe, BbF, and Fla were the dominant monomers. There was noticeable difference of monomers between the industrial area and the residential area in summer and autumn. The monomers, such as BbF, BkF, and BgP, in the residential area were higher than those in industrial area, and the proportion of 5, 6 rings was higher, which indicated that traffic contributed more to the residential area; 3 ring PAHs in industrial area had a higher proportion, which pointed out that their main source was petroleum volatilization. Based on the quantitative source analysis, the PAHs in atmospheric deposition were mainly from traffic emissions, petroleum volatilization, and coal combustion. Three sources of PAHs accounted for 45.7%, 18.4%, 35.9%, and 46.3%, 21.4%, and 32.3%, respectively, in the industrial area and the residential area in winter and spring. In summer and autumn, the contribution of traffic sources to the residential area was as high as 65.2%, and the proportion of the petroleum source to the industrial area increased to 35.5%. Due to high-altitude emissions and favorable diffusion conditions, the coal combustion contribution was significantly reduced.

[Distribution and Ecological Risk of Heavy Metals in the Soil of Redevelopment Industrial Sites].

Fifty typical redevelopment industrial sites in the Putuo, Baoshan, Minhang, and Jiangding districts of Shanghai were chosen to evaluate the ecological risk of heavy metals in the soil. The contents of heavy metal (Hg, Cd, Pb, Cr, and As) in 1847 soil samples, taken from vertical sections, were determined, and their risks were evaluated using the Nemero composite index and Hakanson potential ecological risk index. The average contents of Hg, Cd, Pb, Cr, and As in topsoil samples were 0.33, 0.37, 74.55, 69.23, and 9.05 mg·kg-1, respectively. The contents of Hg, Cd, and Pb exceeded the soil background values of Shanghai, which were 2.75, 2.85, and 2.93 times the background values, respectively. The contents of five heavy metals in soil decreased gradually with increased depth. The contents of heavy metals in deep and saturated soils were close to, or below, the background values, indicating that the anthropic activity disturbance was mainly confined to the topsoil. The accumulation of Hg, Cd, and Pb was the most obvious in Putuo topsoil, with the average contents being 4.25, 4.85, and 3.09 times the background values, respectively. The average contents of Hg and Pb in Baoshan were 4.92 and 6.43 times the background values, respectively. The Nemero Composite Index of Baoshan and Putuo districts were 3.70 and 3.20, respectively, representing heavy pollution level at these sites. The Hakanson potential ecological risk indexes of the Putuo and Baoshang districts were 398.59 and 303.08, respectively, with considerable ecological risk levels. The content and ecological risk of heavy metals at the Minhang and Jiading sites were relatively low. In summary, the pollution of heavy metal in the redeveloped industrial sites is influenced by the operating time, industry type, and past management level of the enterprises. The heavy metal accumulation in the Putuo and Baoshan districts, whose industries developed earlier, were higher than those in the Minhang and Jiading districts. The pollution of heavy metal Hg, Cd, and Pb in soil should be a focus of future work.

[Effects of Manure and Organic Fertilizer Application on Soil Microbial Community Diversity in Paddy Fields].

To investigate the effect of typical manure application on soil microbes in paddy fields, a field experiment on manure application in Chongming Island was carried out. The composition and variety of soil microorganisms in rice paddy fields were analyzed using high-throughput theory (CK), chicken manure (CM), pig manure (PM), and organic fertilizer (OF). The results showed that compared with CK, the application of organic manure increased soil organic matter (SOM), and the application of chicken manure significantly increased the soil ammonia nitrogen (NH4+-N) and total nitrogen (TN) contents (P<0.05). Soil microbial diversity in the PM group was significantly higher than that in the CK group (P<0.05), and the soil microbial community richness in the OF group was significantly higher than that in the CM group (P<0.05). pH, total phosphorus (TP), total nitrogen, and Pb were the important factors affecting the composition of soil microbial communities in paddy fields. The microbial community structure in the CM group was significantly different from those in the other three groups. Compared with CK, the OF group increased the relative abundance of Nitrospira, and the CM group significantly reduced the relative abundance of the denitrifying bacteria Ignavibacteriae (P<0.01) to 40.56%, but significantly increased the relative abundance of nitrifying bacteria Thauera(P<0.05) to 203.00%. The PM group significantly increased the relative abundance of ammoniated bacteria Armatimonadetes (P<0.05) to 57.51% and the anaerobic strain Anaerolinea to 102.00%. The application of chicken manure and pig manure significantly increased the relative abundance of pathogens Pseudomonas and Flavisolibacter (P<0.05), respectively, while the application of organic manure reduced the relative abundance of Flavisolibacter. Overall, the application of manure increased the abundance of bacteria involved in the nitrogen cycle of paddy soils and played a positive role in regulating the nitrogen balance in paddy soils. However, direct application of chicken manure and fresh pig manure increased the abundance of pathogenic bacteria, which had a certain degree of stress on the soil health in the paddy field.

[Heavy Metal Pollution and Potential Ecological Risk of Soil from Reclaimed Industrial Sites and Surrounding River Sediments].

Eight heavy metals (As, Cd, Cr, Cu, Ni, Pb, Zn, and Hg) in the soils from 53 reclaimed industrial sites and 23 river sediments in the Shanghai suburbs were determined using the Nemero pollution index and Hakanson potential ecological risk index (RI). The results show that the eight heavy metals exceed the secondary standard limits to different extents. The rate of standard excess is the most prominent for Cu and Zn; it accounts for 47.17% and 43.40%, respectively. The contents of heavy metals in the sediments from surrounding rivers are significantly lower than those in soil from reclaimed industrial sites. The comprehensive Nemero pollution index of heavy metals in reclaimed soil is 11.41, which represents a serious pollution level; Cu and Zn are the most prominent heavy metals. The Nemero pollution index of heavy metals in surrounding river sediments is 1.26, indicating slight pollution. Based on the single-potential ecological risk, the heavy metals at the reclaimed industrial sites all have a slightly latent ecological risk level, except for Cd (strong), Hg (strong), and Cu (moderate). The potential ecological RI is high (385.79). Heavy metals from the surrounding river sediments have a mild potential ecological risk level, except for Hg. Overall, the potential ecological level is mild (RI=83.91). In short, Cu and Zn are more prominent in reclaimed industrial soil. With respect to the toxic response factor, Cd and Hg should be focused on. The heavy metal pollution of surrounding river sediments is light, leading to a mild potential ecological risk level.

[Composition and distribution characteristics of stable carbon isotope in typical riparian grassland ecosystem]. / å ¸åž‹æ»¨å²¸è‰åœ°ç”Ÿæ€ç³»ç»Ÿç¢³ç¨³å®šåŒä½ç´ ç»„æˆåŠåˆ†å¸ƒç‰¹å¾.

Plant-soil carbon stable isotope characteristics of riparian herbaceous ecosystem were ana-lyzed by measuring the δ13C value of plant tissues from four typical riparian herbaceous plants, which were Cynodon dactylon, Trifolium repens, Festuca arundinacea and Imperata cylindrical, and that of soil organic carbon (SOC) from different vertical depths along Dongfeng Port River in Qingpu District, Shanghai. The result showed that T. repens and F. arundinacea were C3 plants while C. dactylon and I. cylindrical were C4 plants. There was no significant difference between the δ13C va-lue of stem and leaf, litter and root of the four herbaceous plants. The surface SOC δ13C value of C3 and C4 plants strips showed different trends with soil depth, which could be related to the background SOC δ13C value, soil carbon stable isotope fractionation effect and plant root distribution depth as well. Plant input was the main source of SOC and the δ13C composition of plant organisms had direct effect on the SOC δ13C value. The δ13C value of plant components were significantly correlated with the δ13C value of SOC. The SOC content and δ13C value were significantly correlated in the four herbaceous plants strips. The SOC content and δ13C value showed linear negative correlation in C3 plant strips and linear positive correlation in C4 plant strips.