2000～2015年山地城市土地利用景观格局动态演变研究——以重庆市渝北区为例

以重庆市渝北区为例,借助地理信息系统和遥感手段,利用Landsat TM 遥感数据和DEM数据,采用景观指数分析、地形位指数和分布指数等计算方法,对渝北区 2000、2005、2010 和 2015 年土地利用景观格局变化特征进行了分析,着重探讨了不同地形、坡度下各种景观类型变化情况,以及它们之间的相互关系,以期为在相似条件下的城市最佳土地利用模式选择提供一定的借鉴和参考。结果表明：（1）渝北区土地资源以中、高级地形位为主,海拔 200 m 以下,坡度6°以下的土地资源比较匮乏;（2）渝北区主要的景观类型是耕地和林地,但耕地景观总的趋势是不断减少,林地不断增加,建设用地增长较快,总体上景观破碎化程度在增加,景观多样性呈上升趋势;（3）研究期内,中低级地形位区间内大量耕地转变为建设用地,林地、草地景观面积的分布趋势随着地形位指数成正相关关系,其优势地形位主要集中于高级别地形位区间。     

气候变化对江汉平原调水格局的影响

江汉平原水利工程密布,大型调水工程对流域用水格局产生很大影响。气候变化同时会影响调水工程调入调出区供需水情况,从而影响流域的水资源的分配。梳理了江汉平原主要调水工程,重点围绕南水北调中线工程与引江济汉工程的规划设计指标及实际运营状况,分析江汉平原潜在的用水矛盾。此外,在未来气候变化情景下,随着干旱时长和频次增加,会导致各调水工程抽水引水成本提高,从而加剧江汉平原用水矛盾。结果表明:(1)从工程设计和运行来看,南水北调中线工程达到调水设计后,引江济汉工程在保证汉江下游用水需求上受限可能性很大;(2)引江济汉工程自运行以来,虽未有较长时间的泵站抽水引水,但就2018年的泵站抽水引水成本来看已经达到运行总经费的30%。如果引江济汉工程引水口长江水位下降,自流引水受限,使用泵站抽水引水时长及频率将会增加,会导致引水费用进一步增加;(3)"南水北调中线"、"引汉济渭"、"鄂北水资源配置"工程,再叠加汉江中下游生产生活用水,如遇枯水年份,汉江水资源配置会产生很大的矛盾,对汉江流域及汉江生态经济带发展将产生影响。     

膨润土吸附水中有机污染物的应用进展

论述了膨润土的吸附机理,介绍了膨润土的物理及化学改性方法及其对有机染料废水,焦化废水,烟草废水,煤泥水,含酚类、石油烃类、抗生素废水及微污染水等的处理效果。针对膨润土作为环保吸附剂存在的问题指出了今后的研究方向:1)将研究成果应用于实际废水;2)研究环境友好且效果好的改性工艺及材料;3)研究新的吸附剂制备形式;4)加大膨润土在废气处理上的研究力度;5)研制吸附效果更佳且能处理复杂成分污水的新型复合吸附剂。     

Biodegradation of Poly(Aspartic Acid-Itaconic Acid) Copolymers by Miscellaneous Microbes from Natural Water

Poly(aspartic acid-itaconic acid) copolymers (PAI) is a new scale inhibitor for water treatment. Thus, it is necessary to investigate its biodegradability. The biodegradability of PAI was investigated through CO₂ evolution tests under different conditions based on determination of carbon dioxide production. The investigation results showed that the degradation rate of PAI on day 10 and day 28 were respectively 38.7 and 79.5%, indicating that PAI was one kind of easily biodegradable scale inhibitors. With the increase in the content of itaconic acid in copolymerization process, the biodegradability of PAI was significantly reduced. In addition, the high biodegradability might be attributed to the existence of C–N bone-structure and more –COO–. Finally, Cu²⁺ could decrease the degradation percentage and the enzyme inhibition effect of Cu²⁺ was not the linear effect, but the “low-dosage effect”.     

Highly efficient conversion of sugarcane bagasse pretreated with liquid hot water into ethanol at high solid loading

Liquid hot water (LHW), an environmental-friendly physico-chemical treatment, was applied to pretreat the sugarcane bagasse (SCB). Tween80, a non-ionic surfactant, was used to enhance the enzymatic hydrolysis of the pretreated SCB. It found that 0.125 mL Tween80 /g dry matter could make the maximum increase (33.2%) of the glycan conversion of the LHW-pretreated SCB. A self-designed laboratory facility with a plate-and-frame impeller was applied to conduct batch hydrolysis, fed-batch hydrolysis, and the process of high-temperature (50°C) fed-batch hydrolysis following low-temperature (30°C) simultaneous saccharification and fermentation (SSF) which was adopted to overcome the incompatible optimum temperature of saccharification and fermentation in the SSF process. After hydrolyzing LHW-pretreated SCB for 120 h with commercial cellulase, the total sugar concentration and glycan conversion obtained from fed-batch hydrolysis were 91.6 g/L and 68.3%, respectively, which were 9.7 g/L and 7.3% higher than those obtained from batch hydrolysis. With Saccharomyces cerevisiae Y2034 fermenting under the non-sterile condition, the ethanol production and theoretical yield obtained from the process of SSF after fed-batch hydrolysis were 55.4 g/L and 88.3% for 72h, respectively, which were 15.5 g/L and 24.7% higher than those from separate fed-batch hydrolysis and fermentation. The result of this work was superior to the reported results obtained from the LHW-pretreated SCB.     

Current status and historical variations of phthalate ester (PAE) contamination in the sediments from a large Chinese lake (Lake Chaohu)

The residual levels of phthalate esters (PAEs) in the surface and two core sediments from Lake Chaohu were measured with a gas chromatograph–mass spectrometer (GC–MS). The temporal–spatial distributions, compositions of PAEs, and their effecting factors were investigated. The results indicated that di-n-butyl phthalate (DnBP), diisobutyl phthalate (DIBP), and di(2-ethylhexyl) phthalate (DEHP) were three dominant PAE components in both the surface and core sediments. The residual level of total detected PAEs (∑PAEs) in the surface sediments (2.146?±?2.255 μg/g dw) was lower than that in the western core sediments (10.615?±?9.733 μg/g) and in the eastern core sediments (5.109?±?4.741 μg/g). The average content of ∑PAEs in the surface sediments from the inflow rivers (4.128?±?1.738 μg/g dw) was an order of magnitude higher than those from the lake (0.323?±?0.093 μg/g dw), and there were similar PAE compositions between the lake and inflow rivers. This finding means that there were important effects of PAE input from the inflow rivers on the compositions and distributions of PAEs in the surface sediments. An increasing trend was found for the residual levels of ΣPAEs, DnBP, and DIBP from the bottom to the surface in both the western and eastern core sediments. Increasing PAE usage with the population growth, urbanization, and industrial and agricultural development in Lake Chaohu watershed would result in the increasing production of PAEs and their resulting presence in the sediments. The significant positive relationships were also found between the PAE contents and the percentage of sand particles, as well as TOC contents in the sediment cores.     

Research and application of method of oxygen isotope of inorganic phosphate in Beijing agricultural soils

Phosphorus (P) in agricultural ecosystems is an essential and limited element for plants and microorganisms. However, environmental problems caused by P accumulation as well as by P loss have become more and more serious. Oxygen isotopes of phosphate can trace the sources, migration, and transformation of P in agricultural soils. In order to use the isotopes of phosphate oxygen, appropriate extraction and purification methods for inorganic phosphate from soils are necessary. Here, we combined two different methods to analyze the oxygen isotopic composition of inorganic phosphate (δ¹⁸O_P) from chemical fertilizers and different fractions (Milli-Q water, 0.5 mol L^?1 NaHCO₃ (pH = 8.5), 0.1 mol L^?1 NaOH and 1 mol L^?1 HCl) of agricultural soils from the Beijing area. The δ¹⁸O_P results of the water extracts and NaHCO₃ extracts in most samples were close to the calculated equilibrium value. These phenomena can be explained by rapid P cycling in soils and the influence of chemical fertilizers. The δ¹⁸O_P value of the water extracts and NaHCO₃ extracts in some soil samples below the equilibrium value may be caused by the hydrolysis of organic P fractions mediated by extracellular enzymes. The δ¹⁸O_P values of the NaOH extracts were above the calculated equilibrium value reflecting the balance state between microbial uptake of phosphate and the release of intracellular phosphate back to the soil. The HCl extracts with the lowest δ¹⁸O_P values and highest phosphate concentrations indicated that the HCl fraction was affected by microbial activity. Hence, these δ¹⁸O_p values likely reflected the oxygen isotopic values of the parent materials. The results suggested that phosphate oxygen isotope analyses could be an effective tool in order to trace phosphate sources, transformation processes, and its utilization by microorganisms in agricultural soils.     

Efficacy of Si fertilization to modulate the heavy metals absorption by barley (Hordeum vulgare L.) and pea (Pisum sativum L.)

Silicon-based fertilizers and soil amendments can have direct and indirect positive influences on cultivated plants. The solid forms of Si-based substances, the most widespread in use, are efficient only at high application rates due to their low level of solubility. Several types of Si-based substances such as fumed silica, slags from the iron and steel industry, modified slags, and a Si-rich product were tested using barley and pea as silicon accumulative and non-accumulative plants, respectively, at two application rates. The plants were grown under toxic concentrations of heavy metals in a greenhouse. Si-rich materials high in water-soluble Si had a positive effect at both the low and high application rates, and for both plant species. This type of substance can be regarded as Si fertilizer, demonstrating greater efficiency at a low application rate and lessened efficiency at a high application rate for protection of the cultivated plants against accumulation of the heavy metals.

     

环境管理战略转型研究综述

由于经济社会的发展伴随的环境问题越来越复杂,资源相对不足、环境容量有限越来越突出,环境管理转型问题引起越来越多的国内外学者关注。所谓环境管理转型,是指环境管理思维、策略和方式的转变,是以环境质量为目标导向,从被动应对向主动防控的转变。本文通过文献梳理的方法,综述了国内外学术界对于环境管理战略进行的多角度探讨。通过综述发现,国外学者主要注重环境管理理论研究,如环境管理的模型研究和不同环境管理战略的研究,且国外学者在研究不同环境管理战略时,研究对象多为微观层面的企业组织;而我国学者的研究则主要集中在宏观层面,即从国家的角度来探讨环境管理战略如何完成转型,从而促进我国经济社会的良性发展。现有的国内外研究是环境管理战略相关理论发展和实践推行的重要基础,在环境管理战略研究领域,本文认为还有一些问题需要进一步研究:一是环境管理的转型不仅需要宏观层面的统筹、微观方面的变革,也需要从中观层面来推进,所以中观层面的环境管理研究同样具有重要的现实意义。二是环境管理的转型不仅需要法律手段的支撑、经济手段的配置,也需要公民环保意识的觉醒,所以关于公民环保意识层面的研究也需要加强。     

Deodorization of pig manure using lignin peroxidase with different electron acceptors

Odor pollution is a big environmental problem caused by large-scale livestock production in China, and developing a practical way to reduce these odors is pressing. In this study, a combination of 0.2–1.0 U/mL lignin peroxidase (LiP) and one of three peroxides (H₂O₂, CaO₂, 2Na₃CO₃·3H₂O₂) was examined for its efficiency in reducing the release of eight chemicals (propionic acid, isobutyric acid, isocaproic acid, isovaleric acid, phenol, p-cresol, indole, and skatole), NH₃, H₂S, and odor intensity from pig manure. The results showed an approximately 90% reduction in p-cresol, 40–60% reduction in odor intensity, 16.5–40% reduction in indolic compounds, and 25–40% reduction in volatile fatty acids. Being the electron acceptors of LiP, 2Na₃CO₃·3H₂O₂ and CaO₂ performed better than H₂O₂ in reducing the concentration of eight chemicals, NH_3, H₂S, and odor intensity from pig manure. The effect of deodorization can last for up to 72 hr.

Implications: In China, one of the major environmental problems caused by confined feeding is odor pollution, which brings a major threat to the sustainability, profitability, and growth of the livestock industry. To couple the LiP with the electron acceptors, a low–cost, simple, and feasible method for odor removal was established in this study. Based on the study results, a practical treatment method was provided for odor pollution and supply the farm operators a more flexible time to dispose treated manure.