间接原子吸收法测定水中硫化物

通过将水样酸化后转化成硫化氢,用氮气带出,被含有定量且过量的铜离子吸收液吸收。分离沉淀后,通过测定上清液中剩余的铜离子,对硫进行间接定量。方法检出限为0.2 mg·L^-1,对实际水样进行分析,加标回收率在90%～95%之间,结果令人满意。     

1954～2008年衡阳冰冻特征及变化趋势分析

利用1954～2008年街阳8个地面气象观测站数据,对其年代际间曲线和气侯趋势系数进行综合分析,结果表明:衡阳冰冻的年代际间变化经历了上世纪70年代的活跃期,50、90年代的低谷期,目前向正常方向发展.年平均出现冰冻24.5站次,冰冻多发年的出现机率有所加大,但仍处于较低水平.1月中旬～2月上旬是冰冻相对集中时段,其中1月下旬是全年出现冰冻最多旬,而该旬并非气温最低时段.形成冰冻的有利条件是日平均气温0～-1℃,小～中等降雨(雪)过程,日平均风速5.0 m/s以下.衡阳的冰冻发生存在地域性特点,自北向南逐渐减少.轻度冰冻、中等冰冻和重度冰冻各占69.3%、25.4%和5.3%.     

珠江口及南海近海海域大气多环芳烃分布特征

分冬、春两次航次分别采集了珠江口及南海近海海域大气气溶胶样品和气相样品,同时以广州和中山作为陆基对照点,对16种EPA优控多环芳烃进行了分析.结果表明,大气PAHs主要以气态化合物为主,总PAHs(气态+颗粒态)的含量范围为49.6～256.6 ng/m3,平均120.7 ng/m3.珠江口海域大气颗粒态多环芳烃季节变化显著,冬、春航次大气颗粒态多环芳烃的含量分别为6.7～18.0 ng/m3和0.4～5.1 ng/m3,冬季航次期间大气颗粒态PAHs含量的高值主要源于大陆气流对城市群大气PAHs污染的输送,另外干冷的季节亦有利于PAHs向颗粒态的富集.与此相反,气态多环芳烃含量的季节差异不明显.在冬季,随东北季风携带的城市粉尘可以将大气中的气态PAHs捕获,而春季航次的大气PAHs主要来源于西太平洋地区的远程输送和PAHs的海-气交换作用.认为受控于季风活动的水、热因子组合特征,是影响珠江口海域大气PAHs含量与分布的主导因素.     

1954-2008年衡阳冰冻特征及变化趋势分析

利用1954-2008年衡阳8个地面气象观测站数据,对其年代际问曲线和气候趋势系数进行综合分析,结果表明-衡阳冰冻的年代际间变化经历了上世纪70年代的活跃期,50、90年代的低谷期,目前向正常方向发展。年平均出现冰冻24.5站次,冰冻多发年的出现机率有所加大,但仍处于较低水平。1月中旬-2月上旬是冰冻相对集中时段,其中1月下旬是全年出现冰冻最多旬,而该旬并非气温最低时段。形成冰冻的有利条件是日平均气温0— -1℃,小-中等降雨（雪）过程,日平均风速5.0m／s以下。衡阳的冰冻发生存在地域性特点,自北向南逐渐减少。轻度冰冻、中等冰冻和重度冰冻各占69.3％、25.4％和5.3％。     

Experimental studies on ozonation of ethylenethiourea

The experimental study on ozonation of ethylenethiourea(ETU) is conducted.The reaction of gas-phase ETU with 0.63 × 10-6 mol/L ozone is carried out in a 200-L reaction chamber.The secondary organic aerosol(SOA) resulted from the ozonation of gas-phase ETU is observed with a scanning mobility particle size(SMPS).The rapid exponential growth of SOA reveals that the atmospheric lifetime of ETU vapor towards ozone reaction is less than four days.The ozonation of dry ETU particles,ETU-contained water droplets an...     

鄱阳湖生态经济区农村生活垃圾的处理主体及功能研究

鄱阳湖生态经济区农村生活垃圾处理现状不容乐观。本文通过对鄱阳湖生态经济区农村垃圾处置现状的调查分析,从农村生活垃圾处理的四个主体：政府、村民、企业、学校等出发,探索四类主体功能实现的途径及方式,即突出政府职能,强化村民主人意识,鼓励企业加入,夯实学校基础,长期坚持,持续推进,以解决垃圾的日益增长与垃圾处理的矛盾,实现政府、群众、企业与环境的共赢,经济、社会、环境效益的统一,共同造就鄱阳湖生态经济区的美好生活。     

Contaminant removal from low-concentration polluted river water by the bio-rack wetlands

The bio-rack is a new approach for treating low-concentration polluted river water in wetland systems. A comparative study of the efficiency of contaminant removal between four plant species in bio-rack wetlands and between a bio-rack system and control system was conducted on a small-scale (500 mm length × 400 mm width × 400 mm height) to evaluate the decontamination effects of four different wetland plants. There was generally a significant difference in the removal of total nitrogen (TN), ammonia nitrogen (NH₃-N) and total phosphorus (TP), but no significant difference in the removal of permanganate index (COD_Mn) between the bio-rack wetland and control system. Bio-rack wetland planted with Thalia dealbata had higher nutrient removal rates than wetlands planted with other species. Plant fine-root (root diameter ≤ 3 mm) biomass rather than total plant biomass was related to nutrient removal efficiency. The study suggested that the nutrient removal rates are influenced by plant species, and high fine-root biomass is an important factor in selecting highly effective wetland plants for a bio-rack system. According to the mass balance, the TN and TP removal were in the range of 61.03--73.27 g/m² and 4.14--5.20 g/m² in four bio-rack wetlands during the whole operational period. The N and P removal by plant uptake constituted 34.9%--43.81% of the mass N removal and 62.05%--74.81% of the mass P removal. The study showed that the nitrification/denitrification process and plant uptake process are major removal pathways for TN, while plant uptake is an effective removal pathway for TP.     

Green finance and corporate environmental responsibility: evidence from heavily polluting listed enterprises in China

Green finance is not just a global trend, but it has become an important channel for industrialized countries to achieve sustainable growth. However, few studies have discussed the environmental governance effects of green finance from the micro-firm level. Based on the data of Chinese A-share listed firms in heavily polluting industries, we, combining with property rights and environmental regulation, empirically research the influence of green finance on corporate environmental responsibility (CER) performance. Results indicate that green finance has a significant negative effect on the environmental responsibility of heavily polluting firms. The result remains after a series of robustness tests. In addition, property rights and environmental regulation play a moderating role in the above relationship. The negative impact of green finance on CER is stronger in private firms and firms in areas with low environmental regulation intensity. Moreover, we observe that green finance decreases the CER performance of heavily polluting firms by increasing financing constraints, reducing environmental investment, and diminishing technological innovation. This study identifies the external factors that influence CER and also provides implications and theoretical support for the government to improve the setting and the implementation of green finance policy in the future.

     

Cation exchange resin supported nanoscale zero-valent iron for removal of phosphorus in rainwater runoff

Self-made cation exchange resin supported nanoscale zero-valent iron （R-nZVI） was used to remove phosphorus in rainwater runoff. 80% of phosphorus in rainwater runoff from grassland was removed with an initial concentration of 0.72 mg. L-1 phosphorus when the dosage of R-nZVl is 8 g per liter rainwater, while only 26% of phosphorus was removed when using cation exchange resin without supported nanoscale zero-valent iron under the same condition. The adsorption capacity of R-nZVI increased up to 185 times of that of the cation exchange resin at a saturated equilibrium phosphorous concentration of 0.42 mg. L-1. Various techniques were implemented to characterize the R-nZVI and explore the mechanism of its removal of phosphate. Scanning electron microscopy （SEM） indicated that new crystal had been formed on the surface of R-nZVI. The result from inductive coupled plasma （ICP） indicated that 2.1% of nZVI was loaded on the support material. The specific surface area was increased after the load of nanoscale zero-valent iron （nZVI）, according to the measurement of BET-N2 method. The result of specific surface area analysis also proved that phosphorus was removed mainly through chemical adsorption process. X-ray photoelectron spectroscopy （XPS） analysis showed that the new product obtained from chemical reaction between phosphate and iron was ferrous phosphate.     

北江河水中抗生素抗性基因污染初步研究（Preliminary Studies on the Pollution Levels of Antibiotic Resistance Genes in the Water of Beijiang River, South China）

环境中细菌的耐药性,尤其是对抗生素的耐药性已成为影响生态环境的重要因素.论文采用抗生素抗性平板法调查了北江河水中四环素、红霉素及磺胺类这3类抗生素耐药性细菌的存在,采用定性PCR及荧光定量PCR方法分别研究了该水域sul1和sul2这2种磺胺类抗生素抗性基因(ARGs)的存在和含量水平.结果表明,所采集北江水域的9个样品中有5个对四环素有耐药性,7个对红霉素有耐药性,8个对磺胺二甲嘧啶有耐药性;定性PCR实验并经基因测序结果证实,5个样品含有sul1,4个样品含有sul2.进一步的PCR定量分析结果显示,7个样品中均检出sul1和sul2磺胺抗性基因,它们与内对照基因16S-rRNA表达量比值分别在10-2.56~10-0.52及10-3.25~10-1.24范围内,该结果显著高于美国科罗拉多州北部河流的研究结果.此外,数据分析也发现,sul1和sul2磺胺抗性基因的含量水平与该区域水中磺胺含量分布具有一定的相关性,表明外源性抗生素对河流的污染是诱导抗性基因的重要因素.