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901.
Biochemical responses of Pinus massoniana, with and without the inoculation mycorrhizal fungus Pisolithus tinctorius at the root, to artificial acid rain (pH 2.0) and various Ca/Al ratios were investigated. Some enzymes associated with the nutritive metabolism, such as acid phosphatase, alkaline phosphatase, nitrate reductase, mannitol dehydrogenase and trehalase, in the roots, stems and leaves of plant were obviously inhibited by the artificial acid rain and Al. After treatment with pH 2.0 + Ca/Al (0/1 or 1/10) artificial acid rain, the protein content in the organs was decreased. However, the activities of superoxide dismutase (SOD) and peroxidase (POD) and glutathione (GSH) concentrations were induced. It demonstrated that acid rain and Al could induce oxygen radicals in plant. Compared with the treatments with lower pH or Al, respectively, the combination of lower pH and Al concentration was more toxic to P. massoniana. Al toxicity could be ameliorated by the addition of Ca and the amelioration was the most when the ratio was 1/1 among the various Ca/Al ratio. Infection with mycorrhizal fungus P. tinctorius at the root of P. massoniana increased the ability of the plant to resist the toxicity of artificial acid rain and Al stress. 相似文献
902.
903.
Nunez CM Ramsey GH Kong EJ Bahner MA Wright RS Clayton CA Baskir JN 《Journal of the Air & Waste Management Association (1995)》1999,49(3):256-267
Pollution prevention (P2) options to reduce styrene emissions, such as new materials and application equipment, are commercially available to the operators of open molding processes. However, information is lacking on the emissions reduction that these options can achieve. To meet this need, the U.S. Environmental Protection Agency's (EPA) Air Pollution Prevention and Control Division, working in collaboration with Research Triangle Institute, measured styrene emissions for several of these P2 options. In addition, the emission factors calculated from these test results were compared with the existing EPA emission factors for gel coat sprayup and resin applications. Results show that styrene emissions can be reduced by up to 52% by using controlled spraying (i.e., reducing overspray), low-styrene and styrene-suppressed materials, and nonatomizing application equipment. Also, calculated emission factors were 1.6-2.5 times greater than the mid-range EPA emission factors for the corresponding gel coat and resin application. These results indicate that facilities using existing EPA emission factors to estimate emissions in open molding processes are likely to underestimate actual emissions. Facilities should investigate the applicability and feasibility of these P2 options to reduce their styrene emissions. 相似文献
904.
秦皇岛市从1998年5月29日至1999年2月25日空气污染指数平均为84.92,首要污染物是总悬浮微粒(TSP),空气质量Ⅱ级,属良好范围,在北方城市中仅次于大连和烟台。影响秦皇岛市空气质量的不利因素有煤炭运输规模大、建筑工地及城市卫生管理不严、绿地分布不合理、集中供热规模偏小等。为此,应继续治理煤尘,实行热电连产,改进绿化,加强管理。 相似文献
905.
906.
Transformation of erythromycin during secondary effluent soil aquifer recharging: Removal contribution and degradation path 总被引:1,自引:0,他引:1
Liangliang Wei Kena Qin Ningbo Zhao Daniel R. Noguer Wei Qiu Qingliang Zhao Xiangjuan Kong Weixian Zhang Felix Tetteh Kabutey 《环境科学学报(英文版)》2017,29(1):173-180
Erythromycin (ERY), a widely used antibiotic, has recently been detected in municipal secondary effluents and poses serious threats to human health during wastewater reusing. In this study, the removal, fate, and degradation pathway of ERY in secondary effluent during soil aquifer treatment was evaluated via laboratory-scale SAT tests. Up to a 92.9% reduction of ERY in synthetic secondary effluent was observed in 1.0 m depth column system, which decreased to 64.7% when recharged with wastewater treatment plant secondary effluent. XRD-fractionation results demonstrated that the transphilic acid and hydrophobic acid fractions in secondary effluent compete for the adsorption sites of the packed soil and lead to a declined ERY removal. Moreover, aerobic biodegradation was the predominant role for ERY removal, contributing more than 60% reduction of ERY when recharged with synthetic secondary effluent. Destruction of 14-member macrocyclic lactone ring and breakdown of two cyclic sugars (l-cladinose and d-desosamine) were main removal pathways for ERY degradation, and produced six new intermediates. 相似文献
907.
A novel poly(ethyleneimine)/Au nanoparticles/hemin nanocomposite(PEI-AuNPs-Hemin)acting for Methyl Orange(MO) removal has been synthesized. PEI-AuNPs was prepared firstly and it was then linked to hemin through the coupling between carboxyl groups in hemin and amino groups in PEI without the activation of carboxyl groups. The high reactivity and stability of AuNPs contributed greatly in the formation of the amido bonds in the nanocomposite. Fourier transform infrared spectroscopy, transmission electron microscopy and UV–visible spectroscopy were used to characterize the PEI-AuNPs-Hemin.Results show that PEI-AuNPs-Hemin has strong adsorption for MO. Adsorption and degradation experiments were carried out at different p Hs, nanocomposite concentrations and UV irradiation times. Removal of MO in acidic solutions was more effective than in basic solutions. The real-time study showed that the MO degradation with the nanocomposite under UV irradiation was a fast process. In addition, the photocatalytic degradation mechanism was proposed. The study suggests that the PEI-AuNPs-Hemin may have promising applications in environmental monitoring and protection. 相似文献
908.
水生生物水质基准是水质基准体系的重要组成部分。由于不同地区的生态体系存在差异,所需要推导的水质基准也存在不同。目前太湖流域的水质基准研究刚刚起步,国内外制订的水质标准并不能代表太湖流域的水生生物和环境特征。因此,开展基于太湖流域的水生生物和环境特征的水质基准研究,对于太湖流域的水环境保护和水质管理具有重要的作用和意义。在水生生物水质基准的物种选择方面,选择了两种鱼类、两种浮游动物、3种底栖动物以及一种水生植物或浮游藻类,可以全面的代表太湖流域的水生态结构和营养等级。 相似文献
909.
Distributed photovoltaic (PV) generation is a promising pathway for reducing carbon emission and meeting energy demands in electricity sector. Subsidies are essential to accelerate its deployment. This paper aims to study the optimal subsidy levels for distributed PV generation from the perspective of maximizing the net policy benefits (environmental and economic) by applying the principal–agent theory, which is a commonly used method of analyzing government incentive issues. Based on a detailed analysis of asymmetric information and of benefit conflicts between the government (the principal) and the investor (the agent), the optimal subsidy principal–agent model is established, in which the investor’s preference toward distributed PV generation is asymmetric and is described by a random variable. The equivalent model is then presented to obtain the optimal solutions, and a numerical example is provided to test the effectiveness of the model and to illustrate the implications of the solutions. The results show that high net policy benefits are directly influenced by a high investor preference. This emphasizes the importance for the government of improving the investor’s preference level and of eliminating asymmetric information to develop distributed PV generation and reduce subsidy costs. Additionally, lowering the market risk and enlarging the overflow value of distributed PV generation both contribute to subsidy cost savings. This paper offers policy makers an effective subsidy scheme to accelerate distributed PV generation development and will also be a useful reference for government to subsidize other renewable power systems to mitigate global climate and energy changes. 相似文献
910.
建立了高效液相色谱法测定水样中N,N-二甲基甲酰胺(DMF)、N,N-二甲基乙酰胺(DMAC)和二甲基亚砜(DMSO)含量方法.本方法采用Venusil MP C18色谱柱,流动相乙腈:水(6:94,v/v),测定波长为:DMF与DMAC 220 nm;DMSO 210 nm.目标物在约0.5~10 mg·L-1范围内呈良好线性,线性相关系数r在0.999以上,检出限分别为:DMF与DMAC 0.02 mg·L-1、DMSO 0.1 mg·L-1,加标回收率在97%~109%,相对标准偏差RSD≤2%.本法前处理简单、有机溶剂消耗少,操作方便快捷. 相似文献