生态文学视角下《寂静的春天》和《复合污染》的对比

美国作家蕾切尔·卡逊通过对杀虫剂的危害研究,于1962年出版了《寂静的春天》。之后,有吉佐和子受此部作品的影响,从日本生态环境污染的角度出发,于1975年发表了《复合污染》。本文主要通过对这两部作品进行对比,来探究其生态思想及其社会作用。

从《复合污染》看有吉佐和子的创作思想

有吉佐和子是日本现代女性文学作家。《复合污染》于1974年10月~1975年6月在《朝日新闻》上连载,是一部围绕社会问题而作的大众文学作品,它也是最能代表有吉创作倾向的作品。作品中对日本崇拜美国追求农业现代化、不惜牺牲生态环境造成污染问题日益严峻的恶果进行了无情的批判,对化学制品对日本普通民众的生活恶劣影响和恶性循环复合链条进行了深刻的反思,同时不断拷问日本政府的不作为和日本人性格中的弊端,表现出有吉佐和子作为知识女性的良知、深刻的洞察力,也为世人敲响了警钟。

Growth Response and Metal Accumulation of Sedum alfredii to Cd/Zn Complex-Polluted Ion Levels

Sedum alfredii Hance has been identified as a new Zn-hyperaccumulator native to China. In this study, responses and metal accumulation of S alfredii were examined under Zn/Cd complex polluted conditions. The results showed that optimal growth of S alfredii in terms of the maximum dry matter yield was observed at Zn/Cd complex level of 500/100 mumol/L. Plant cadmium (Cd) or zinc (Zn) concentrations increased with increasing Cd or Zn supply. During the 20 d treatment, the highest Cd concentration in the leaves reached 12.1 g/kg at Zn/Cd level of 50/400 mumol/L and that of Zn in the stems was 23.2 g/kg at Zn/Cd level of 1000/50 mumol/L. The distribution of Cd in different plant parts decreased in the order: leaf > stem greater than or equal to root, whereas that of Zn was: stem > leaf greater than or equal to root. The accumulation of Cd and Zn in the shoots and roots of S. alfredii increased with the increasing of Zn/Cd supply levels, peaked at Zn/Cd levels of 250/400 and 500/100 mumol/L, respectively. The highest Cd and Zn uptake by the shoots was approximately 5 and 11 mg/plant, and was over 20 and 10 times higher than those in the roots, respectively. Zn supply at levels less than or equal to 500 mumol/L increased plant Cd concentrations, whereas high Zn supply decreased root Cd but did not affect leaf Cd concentrations in S alfredii Low Cd supply increased Zn concentration in the leaves, but Cd supply higher than 50 mumol/L considerably reduced root Zn concentrations, especially at low Zn level. These results indicate that S. alfredii can tolerate high Zn/Cd complex levels and has an extraordinary ability to hyperaccumulate not only Zn but also Cd. It could provide a new valuable plant material for understanding the mechanisms responsible for co-hyperaccumulation of Zn and Cd as well as for phytoremediation of the Cd/Zn complex polluted soils.

Effects of Combined Pollution of Pb and Cd on Growth and Yield of Rice

[Objective] The aim was to study the damage and the mechanism of combined pollution of Pb and Cd on rice growth,yield and quality of rice. [Method]Effects of combined pollution of Pb and Cd on the growth and yield of rice were studied by pot experiment with cultivating rice. [Result] Pb and Cd could promote rice growth at low concentration while inhibit plant height at high concentration; Pb and Cd stress reduced the number of rice tillers significantly,with the increasing of stress concentration,the decrease amplitude of the number of tillers was greater; the panicle per pot,seed setting rate,1 000-grain weight and yield of rice were reduced significantly by Pb and Cd stress,the grain number per panicle decreased significantly under low concentration of Pb and Cd but increased significantly under high concentration; the brown rice rate and milled rice rate increased significantly under low concentration of Pb and Cd while at high concentration of Pb and Cd,the both two reduced significantly,the head milled rice rate reduced significantly with the decreasing of concentration; The Pb and Cd content of grains were significantly positively related to the concentrations of Pb and Cd content in soil,it had excessively exceeded hygienic standard when the concentrations of Pb and Cd in soil were medium-high and the unqualified rate reached 333% and 122%. [Conclusion]The study had provided basis for the establishment of rice cultivation system in pollution areas.

Mechanical properties of anti-seepage grouting materials for heavy metal contaminated soil

Cement-based composite grouting materials were used to construct grouting cutoff wall for heavy metal contaminated soil in non-ferrous metal mining areas. Cement, fly ash, and slag as principal ingredients were mixed with water glass in different ways to produce three composite grouting materials. In order to investigate the effect of water glass mixing ratio, Baume degree, fly ash and slag contents on the mechanical properties of the composite grouting materials, particularly their gel time and compressive strength, the beaker-to-beaker method of gel time test and unconfined compressive strength test were conducted. In addition, the phase composition and microstructure of the composite grouting materials were analyzed by the X-ray diffraction（XRD） and scanning electron microscope（SEM） techniques. The test results show that their gel time increases when water glass mixing ratio and Baume degree increase. The gel time increases dramatically when fly ash is added, but decreases slightly if fly ash is partly replaced by slag. When the mixing ratio of water glass is below 20%, their compressive strength increases with the increases of the ratio; when the ratio is above 20%, it significantly decreases. The compressive strength also tends to increase as Baume degree increases, and improves if fly ash and slag are added.

Characteristics of complex air pollution in typical cities of North China

The Beijing-Tianjin-Hebei urban agglomeration is currently facing severe complex air pollution. In this paper, simultaneous observations conducted in 2014 show that the annual mean concentration of fine particulate matter （PM2.5） was 84 ± 70, 86 ±60, and 118 ± 95 μg m-3 in Beijing, Tianjin, and Shijiazhuang, respectively. The mean 03 8h max in the summer was 171 ± 43, 147 ± 45, and 146 ± 44 μg m-3, respectively. This research indicates that PM2.5 and O3 are positively correlated when the temperature exceeds 20 ℃5 and the urban agglomeration shows characteristics of complex air pollution consisting of superimposed 03 and PM2.s. In summer, when the humidity was less than 55%, secondary particles and 03 also increased in a coordinated manner （y = 1.35x ＋ 29.85; R2 = 0.61）, which demonstrates severe complex pollution. However, the mean PM2.5（y） and mean 03 8 h max （x） in summer showed a negative correlation （y = - 1.3x ＋ 245; R2 = 0.61 ） in the three regions, indicating high concentrations of PM2.5 pollution partially inhibit O3 generation.

Preparation by enzymolysis and bioactivity of iron complex of fish protein hydrolysate (Fe-FPH) from low value fish

Preparation of Fe^2＋ chelate of fish protein hydrolysate （Fe-FPH） obtained from low value fish proteins was introduced and its bioactivity was studied by compound enzymolysis. The optimum conditions for hydrolysate chelating Fe^2＋ are DH （degree of hydrolysis） at 5%, pH 7.0, 20℃ and 15 min chelating time for FM （material not being defatted）. Four types of Fe-FPH including CA （deposit after chelating）, CB （deposit in 50% of absolute ethanol solution）, CC （suspended deposit in 80% of absolute ethanol solution）, and CD （bottom deposit in 80% of absolute ethanol solution） were fractionated with absolute ethanol from FM. Structural analysis through infra-red spectrum revealed that Fe^2＋ was combined strongly with amino-group and carboxyl-group in each chelate and each Fe^2＋ could form two five-member ring structures. All of the four chelates were shown more significant antioxidative activity and can be used as natural hydrophobic and hydrophilic antioxidant. Among all the chelates, the CB possesses the most effective antioxidative activity at 92% as high as that of a-tocopherol. Among all Fe-FPHs, only CD showed the most effective antibacterial activity against Escherichia coli, Staphylococcus aureus, Salmonella typhi, and Bacillus subtilis and can be used as natural antibacterial. It provides a more effective way for utilization of low value fish proteins and key information of Fe-FPH as additive in food industry.

Fouling-resistant Composite Membranes for Separation of Oil-in-water Microemulsions

Fouling-resistant ceramic-supported polymer composite membranes were developed for removal of oil-in-water （O/W） mieroemulsions. The composite membranes were featured with an asymmetric three-layer structure, i.e., a porous ceramic membrane substrate, a polyvinylidene fluoride （PVDF） ultrafiltration sub-layer, and a polyamide/polyvinyl alcohol （PVA） composite thin top-layer. The PVDF polymer was east onto the tubular porous ceramic membranes with an immersion precipitation method, and the polyamide/PVA composite thin top-layer was fabricated with an inteffaeial polymerization method. The effects of the sub-layer composition and the recipe in the inteffaeial polymerization for fabricating the top-layer on the structure and performance of composite membranes were systematically investigated. The prepared composite membranes showed a good performance for treating the O/W microemulsions with a mean diameter of about 2.41μm. At the operating pressure of 0.4MPa, the hydraulic permeability remained steadily about 190L·m^-2·h^-1, the oil concentration in the permeate was less than 1.6mg·L^-1, and the oil rejection coefficient was always higher than 98.5% throughout the operation from the beginning.

Fixation of Multiple Metals in Contaminated Soil by Different Passivators

The effects of 4 passivators, zeolite, lime, red mud and peanut shell biochar, on the fixation of Cd, Pb, Cu and Zn in acidic multi-metal contaminated soils were studied by passivator culture experiment in order to screen out the passivator with better fixation effects. The results showed that the soil pH values of zeolite, lime, red mud and peanut shell biochar increased significantly by 0.511.02, 0.821.29, 0.720.89 and 0.300.35 respectively. The effects of 4 passivators on the fixation of Cd and Zn in soil are lime>red mud>zeolite>peanut shell biochar. The order of effects on the fixation of Pb is red mud>lime>zeolite>peanut shell biochar. The order of the fixation effects of Cu is red mud>lime>peanut shell carbon>zeolite. The contents of Cd, Pb, Cu and Zn in the extractable state of CaCl2 decreased with the increase in the dosage of 4 passivators. Lime and red mud showed good fixation effects on Cd, Pb, Cu and Zn. The contents of Cd, Pb, Cu and Zn in the extractable state of CaCl2 at the low dosage(2.5 g/kg) of lime and red mud decreased by 41%, 84%, 76% and 83% respectively. Soil pH value was negatively correlated with CaCl2-Cd, Pb, Cu and Zn(P<0.01). Lime and red mud had significant fixation effects on Cd, Pb, Cu and Zn in acidic multi-metal contaminated soils at low application dosages.

Synergistic photocatalytic effect of porous g-C_3N_4 in a Cr(Ⅵ)/4-chlorophenol composite pollution system

The photocatalytic reduction of aqueous Cr(VI)to Cr(III)was preliminarily studied using porousg‐C3N4as a photocatalyst under acidic conditions.The observed synergistic photocatalytic effect ofporous g‐C3N4on a Cr(VI)/4‐chlorophenol(4‐CP)composite pollution system was further studiedunder different pH conditions.Compared with single‐component photocatalytic systems for Cr(VI)reduction or4‐CP degradation,the Cr(VI)reduction efficiency and4‐CP degradation efficiency weresimultaneously improved in the Cr(VI)/4‐CP composite pollution system.The synergistic photocatalyticeffect in the Cr(VI)/4‐CP composite pollution system can be attributed to the acceleratedredox reaction between dichromate and4‐CP by electron transfer with porous g‐C3N4.

Application of polymeric aluminum salts in remediation of soil contaminated by Pb,Cd,Cu,and Zn

Soil contaminated with typical heavy metals (Pb,Cd,Cu,and Zn) was remedied by using the polymeric aluminum salt coagulants including polyaluminum chloride (PAC) and polyaluminum sulfate (PAS).The remediation efficiencies are influenced by reaction time,water amount,and dosage of remediation agent.The optimal remediation conditions are as follows:6 h of reaction time,1 kg/kg of water addition amount,and 0.25 kg/kg of remediation agent dosage.After PAC addition,the remediation efficiencies of diethylenetriamine-pentaacetic acid (DTPA)-extractable Pb,Cd,Cu,and Zn reach 88.3%,85.1%,85.4%,and 73.7%,respectively;and those for PAS are 89.7%,88.7%,83.5%,and 72.6%,respectively.The main remediation mechanism of the polymeric aluminum salt may contribute to the ionization and hydrolysis of PAC and PAS.H + released from ionization of polymeric aluminum salt can cause the leaching of heavy metals,while the multinuclear complex produced from hydrolysis may result in the immobilization of heavy metals.For PAC,the immobilization of heavy metals is the main remediation process.For PAS,both leaching and immobilization are involved in the remediation process of heavy metals.

Dechlorination of Chlorinated Aliphatic Compounds by Micro-scale Al-Zn-Mg/Fe Powders as Advanced Zero-valent Iron

Micro-scale Al-Zn-Mg/Fe composite powders (MAF) with high reactivity and good storage properties were prepared by reducing iron onto the surface of Al-Zn-Mg alloy powders. Experimental results show that MAF as advanced zero-valent iron are highly effective for degradation of chlorinated organic compounds. The efficiency of degradation for carbon tetrachloride and perchloroethylene is higher than 99% within a period of 2 h. The efficiency of degradation for trichloroethylene by MAF after storing for one month is equivalent to that by freshly prepared nano-size zero-valent iron particles.

Comparison of Heavy Metal Accumulation in Four Vegetables Grown in the Soils Contaminated with Multiple Heavy Metals

In order to compare the differences in the accumulation of plumbum(Pb),cadmium(Cd),chromium(Cr),cuprum(Cu),nickel(Ni)and zinc(Zn)from the multi-contaminated,alkalescent soil in the plants of four-season big-leaf coriander,butter lettuce,four-season fast-growing pakchoi and four-season parsley to choose low accumulation vegetables,a pot experiment was conducted by using heavy metal salts to simulate high-,moderate-and low-level heavy metals multi-contaminated soils.The results showed that the multi-contaminated soil by high levels of Pb,Cd,Cr,Cu and Zn produced inhibition on biomass of four-season fast-growing pakchoi,failing to collect samples,but had no obvious inhibition on the growth of the three other vegetables.Among the four kinds of vegetables examined,the accumulation ability of four-season parsley to the five heavy metals of Pb,Cd,Cr,Cu and Zn was the strongest,while the accumulation ability of four-season fast-growing pakchoi to Ni was the strongest.In the high-level contaminated soil,the underground part of these four vegetables grown was more likely to accumulate heavy metals than their aboveground part.Both of vegetable varieties and heavy metal types can affect the accumulation of heavy metals in vegetables.Our research also found that four-season big-leaf coriander was high yielding and low accumulation of heavy metals.

Ecological Risk Assessment of Combined Pollution of Heavy Metals and Pesticides in Urban Soils

Urban soil is the main component of urban ecological systems and the key risk receptor from urbanization. Heavy metal and green pesticide pollutions in urban soils have been widely reported with the expanding of urbanization. Since urban soil pollution comes from various resources, application of integrated thinking and methods is needed in ecological risk assessment of urban soil pollution. This paper synthetically reviewed the combined pollution of heavy metals and pesticide, and ecological risk assessment, and then proposed some research trends and areas in the future that are required to carry out intensively according to the present situation of environmental pollution and international research fronts.

Preparation of Photocatalytic TiO_2 and TiO_2-SiO_2 Particles and Application to Degradation of Trace Organics in Aqueous Solution

TiO2 and TiO2-SiO2 photocatalysts were prepared by sol-gel and supercritical CO2 fluid drying method and characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), etc. Their catalytic properties were tested through the photocatalytic degradation of phenol and aniline in wastewater. The results show that the developed fluidized photocatalytic reactor (FPR) and TiO2 catalyst had better performance in degrading pollutants as compared with slurry photocatalytic reactor (SPR) and commercial TiO2 catalyst. The composition and crystal form of TiO2-SiO2 composite oxide had obvious influence on catalytic effect and TiO2-SiO2 photocatalysts showed better catalytic activity and stability.

Surface Morphology of Reactive Powder Concrete Containing Soil

Recent studies have revealed that concrete can be used as a media to contain As （arsenic） removed from drinking water. Concrete, which is a composite material, has been effective in solidifying hazardous wastes and contaminated soils. A research project was conducted to study the effects of uncontaminated soil and arsenic contaminated soil on the microstructure of concrete to qualitatively define the mechanisms of the encapsulation of soils containing inorganic material such as arsenic by application of solidification/stabilization technique. This research paper focused on studying the surface morphology of RPC （reactive powder concrete） containing soil.

Magnetite/Reduced Graphene Oxide Nanocomposites： One Step Solvothermal Synthesis and Use as a Novel Platform for Removal of Dye Pollutants

A simple one step solvothermal strategy using non-toxic and cost-effective precursors has been developed to prepare magnetite/reduced graphene oxide （MRGO） nanocomposites for removal of dye pollutants. Taking advantage of the combined benefits of graphene and magnetic nanoparticles, these MRGO nanocomposites exhibit excellent removal efficiency （over 91% for rhodamine B and over 94% for malachite green） and rapid separation from aqueous solution by an external magnetic field. Interestingly, the performance of the MRGO composites is strongly dependent on both the loading of Fe304 and the pH value. In addition, the adsorption behavior of this new adsorbent fits well with the Freundlich isotherm and the pseudo-second-order kinetic model. In further applications, real samples--including industrial waste water and lake water--have been treated using the MRGO composites. All the results demonstrate that the MRGO composites are effective adsorbents for removal of dye pollutants and thus could provide a new platform for dye decontamination.

Preparation of graphene-MoS_2 hybrid aerogels as multifunctional sorbents for water remediation

The increasing demand of clean water and ef- fective way to recycle industrial wastewater has offered a new application for carbon-based three-dimensional （3D） porous networks as sorbents due to their superior sorption abilities. Through the surface modification and hybridization with functional materials, the physical and chemical properties of the 3D carbon-based materials can be engineered. In this work, graphene-MoS2 aerogels （GMAs） with bulky shape are synthesized via a one-pot hydrothermal method. The obtained GMAs show quick sorption rate and high sorption capacity towards a wide variety of contaminants. The sorption covers not only organic solvents or organic dyes, but also toxic heavy metals ions such as Hg2＋ and Pb2＋. More importantly, the sorption capacity towards metal ions can be optimized by simply changing the loading amount of MoS2.