郑州市水污染物排放现状及分析研究

随着经济的进步,水污染问题日益凸显,水资源短缺越来越严重,这不仅制约了城市的经济、社会、环境的可持续发展,更是对人体健康造成了威胁,为了解郑州市近年来污染物排放状况及对其原因进行分析,本文对近几年污染物排放量进行调查,结果表明污水排放总量逐渐上升,这与人口增加、工农业需水量增加有关;主要限排物质COD、氨氮的排放量总体呈下降趋势,但个别年份出现突增现象,这可能与政府的环保政策改变及个别工业偷排有关,对此本研究提出相适应的建议.     

Study on the investment value and investment opportunity of renewable energies under the carbon trading system

China has promised to start the national carbon trading system in 2017. In the carbon trading system, the renewable energy projects may obtain additional benefits through the Certified Carbon Emission Reduction (CCER) trade. As the carbon price fluctuates along with the market conditions, such fluctuation enables the renewable power projects to acquire the rights of an option, i.e. it may contain an even higher value due to the uncertainties in the future. While making an investment decision, the renewable power companies may choose to make the investment immediately, or postpone the investment and accumulate more information to increase the return of investment; and for immediate investments, the return must be sufficient to exceed the potential value of a waiting option. To study the investment in renewable power projects subject to the fluctuation of carbon price, this paper adopts the trinomial tree model of real options to estimate the net present value (NPV) and real option value (ROV) of three types of renewable power projects; according to the decision-making rules of real options to defer, all the three types of projects will exercise the option to postpone the investment decision. This thesis also calculates the benchmark prices of the three types of renewable projects at different times, in the two situations of having no government subsidy and having the government subsidy, so as to determine the investment opportunity of a project. The benchmark price decreases gradually along with the increase of government subsidy, indicating that the government subsidy will stimulate the investment in renewable projects. The benchmark price also increases gradually along with the lapse of time, indicating that the uncertainty will increase together with the time span and thus requires an even higher carbon price to determine the investment opportunity. This thesis also analyzes the sensitivity of factors affecting the investment in renewable projects and draws the conclusion that the fluctuation of carbon price is positively related with the benchmark price of renewable power projects, which indicates that the fluctuation of carbon price increases the option value of an investment but postpones the time of investment. As the China’s carbon trading system improves gradually, the carbon price will reach a stable status, thus stimulate the power companies to invest in the renewable projects.     

Efficient removal of cadmium ions from water by adsorption on a magnetic carbon aerogel

Environmental Science and Pollution Research - Carbon aerogels are attracting much attention as adsorbents due to their high specific surface and large accessible pores. Herein, we describe a...     

Simultaneous measurements of arsenic and sulfide using diffusive gradients in thin films technique (DGT)

Diffusive gradients in thin films technique (DGT) is a dynamically passive sampling technique which has been applied increasingly to the environmental monitoring field. In the preliminary period, the DGT with zirconium hydroxide-silver iodide as the binding phase (ZrO-AgI DGT) has been developed for the determination of sulfide (S(II)). On this basis, this paper developed its determination method for inorganic arsenite (As(III)) to further realize the simultaneous and high-resolution measurements of labile inorganic As and S(II) in sediments. ZrO-AgI binding gel had a strong ability in adsorbing and fixing As(III), showing a linear increase in the initial 12.5 min. After saturation of S(II) on ZrO-AgI binding gel, the adsorption rate and adsorption capacity of As(III) reduced by 8 and 14%, respectively. A stable elution rate (89.1 ± 2.2%) was obtained by extraction of As(III) on the binding gel using a mixture solution of 1.0 M NaOH and 1.0 M H₂O₂ (1:1). The DGT capacity of As(III) determined by the ZrO-AgI DGT was 23.6 μg cm^?2. DGT uptakes of As(III) were independent of pH (4.0–9.0) and ionic strength (0.01–100 mM), and they did not interfere with each other during the uptake process. Simultaneous measurements of labile As and S(II) in four sediment cores of Taihu Lake (China) with ZrO-AgI DGT showed that they had similarly vertical distributions in the top 16-mm layer in one core and in the whole profile up to the 35 mm depth in two cores. It likely reflected a simultaneous release of As and S(II) in sediments by synchronous reduction of As-hosted oxidized iron and sulfate, respectively. The simultaneous decreases of labile As and S(II) from their co-precipitation (e.g., As₂S₃) were not obvious in deeper sediment layer through the measurement with ZrO-AgI DGT.     

Occupational Safety and Health Status of Sanitation Workers in Urban Areas: A Pilot Study From Wuhan,China

Sanitation workers ‘ workload increases quickly with rapid urbanization, but there is almost no evidence or policy recommendations for their management in developing countries. This study describes the health status and occupational protection of sanitation workers; it also explores risk factors related to their health status in Wuhan City, China. Three hundred and eighty-five sanitation workers from 54 streets of Wuhan were surveyed. Their prevalence of 2-week illness and arthritis was relatively higher than in the general population in China. Findings related to occupational protection showed that both sanitation workers (users) and their managers (providers) neglected the role of low-cost protection measures, especially masks, soap/hand sani-tizer and prejob training (use rate of 7.27%, 26.75% and 43.64%, respectively). High-intensity workload was an important risk factor for 2-week illness, and prejob training was an important protective factor against arthritis.     

Variations of organochlorine pesticides and polychlorinated biphenyls in atmosphere of the Tibetan Plateau: Role of the monsoon system

Monsoon transport is an important process that influences the global transport of persistent organic pollutants. Only a few studies focused on the influence of monsoon on organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) levels in the Tibetan Plateau. In this study, 19 samples were collected in Lhasa, the capital of Tibet Autonomous Region, using a high-volume air sampler. The average concentrations of α-HCH, γ-HCH, p-p′-DDT, p-p′-DDE, o-p′-DDT, α-endosulfan, β-endosulfan and PCBs (including PCB-28, 101, and 118) were 2.3, 10.3, 3.2, 2.9, 5.8, 6.3, 2.2, and 10.6 pg m^?3, respectively. The weak correlation coefficients between lnp (natural logarithm of partial pressure) and 1/T (reciprocal temperature) were obtained for DDTs and β-endosulfan (r² values ranged from 0.13 to 0.41). However, no significant correlations were obtained for HCHs and PCBs. These results suggested that both local emission and long-range atmospheric transport (monsoon) may influence the distribution of OCPs at Lhasa. In this study, peak concentrations of DDTs, endosulfans and PCBs were found in August, when Eastern Monsoon system occurred. However, the maximum concentrations of HCHs appeared in June (Indian Monsoon is the dominant air circulation pattern). Monthly variation of OCP/PCB levels was likely associated with the different air sources of monsoon system.     

Interactive response of photosynthetic characteristics in Haloxylon ammodendron and Hedysarum scoparium exposed to soil water and air vapor pressure deficits

C₄ plants possess better drought tolerance than C₃ plants. However, Hedysarum scoparium, a C₃ species, is dominant and widely distributed in the desert areas of northwestern China due to its strong drought tolerance. This study compared it with Haloxylon ammodendron, a C₄ species, regarding the interactive effects of drought stress and different leaf–air vapor pressure deficits. Variables of interest included gas exchange, the activity levels of key C₄ photosynthetic enzymes, and cellular anatomy. In both species, gas exchange parameters were more sensitive to high vapor pressure deficit than to strong water stress, and the net CO₂ assimilation rate (A_n) was enhanced as vapor pressure deficits increased. A close relationship between A_n and stomatal conductance (g_s) suggested that the species shared a similar response mechanism. In H. ammodendron, the activity levels of key C₄ enzymes were higher, including those of phosphoenolpyruvate carboxylase (PEPC) and nicotinamide adenine dinucleotide phosphate-malate enzyme (NADP-ME), whereas in H. scoparium, the activity level of nicotinamide adenine dinucleotide-malate enzyme (NAD-ME) was higher. Meanwhile, H. scoparium utilized adaptive structural features, including a larger relative vessel area and a shorter distance from vein to stomata, which facilitated the movement of water. These findings implied that some C₄ biochemical pathways were present in H. scoparium to respond to environmental challenges.     

基层环保面临的危险废物管理问题及对策研究

近年来,中国在危险废物管理方面出台了一系列法律、法规、标准及日常管理文件,加大了对危险废物的监管力度,危险废物规范贮存、处置工作不断加强,非法转移现象也得到有效遏制,有力促进了危险废物管理的标准化、规范化、程序化。但是,当前在实际工作中,特别是一线基层环保危险废物管理,还存在管理机构、人员不到位,环保部门及企业业务知识缺乏,危险废物规范化处置能力不足,对是否属于危险废物管理的废物鉴定有资质的单位很少、鉴定费用极其昂贵,废物综合利用率、资源化水平不高以及国家在危险废物上管理的法律法规不够健全或缺乏实际操作性等问题。提出了应从提高对废物综合利用率的角度,进一步完善危险废物管理的法律体系,打破危险废物利用和处置的地方保护,充分利用市场调节和优化资源配置,解决企业危险废物处置难的问题。同时,加强对环保管理机构能力建设,促进危险废物处理的资源化、规范化和安全化。     

中国水污染源监测方法标准技术体系研究

通过梳理中国水污染源监测方法标准体系发展历程,剖析其构成及技术应用现状,对比国际先进监测技术体系,总结了中国水污染源监测方法标准体系特点,并结合国内外分析技术现状、发展趋势,提出了中国水污染源监测方法标准体系技术发展方向：一是常规监测更加自动化、智能化;二是加强重金属形态分析能力,建立ICP-MS监测方法标准;三是强化有机监测仪器、标准品和耗材研发力度,提高LC-MS、GC-MS利用率;四是建立生物监测标准方法群.     

硅砂矿土地复垦与植被恢复研究

根据彰武县阿尔乡北甸子硅砂矿地貌、自然条件及周边环境等特征,确定硅砂矿土地复垦的方向为林地和鱼塘。简要介绍硅砂矿土地复垦的开采流程及闭坑后土地复垦与植被恢复的技术要求,提出土地复垦和植被恢复过程具体措施及预防控制。通过开展硅砂矿土地复垦与植被恢复工作,把破坏的土地采取整治措施恢复为可利用的土地,缓解了矿区土地减少的趋势,改善了矿山生态环境,最终实现矿山生态环境保护、土地资源利用与地方经济可持续发展。