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971.
虚拟水贸易理论及其政策化研究进展 总被引:2,自引:0,他引:2
虚拟水贸易理论为水资源管理提供了全新的视角。通过虚拟水贸易,一方面可以通过进口虚拟水缓解缺水国家和地区实体水资源紧缺的状况,提高水资源在更广阔的空间范围内的配置效率;另一方面虚拟水的进口主要通过农产品贸易实现,对一国的粮食安全形成冲击。将虚拟水贸易理论政策化必须综合衡量这两方面的利弊。本文对虚拟水贸易理论及其政策化的研究进展进行了较为全面的梳理,得出结论认为:虚拟水贸易对缓解部分贫水国家和地区的水资源紧缺状况确实有效,但是并不适用于全部国家和地区;不能仅仅从虚拟水角度提倡进口粮食,而应与其他生产要素及影响因素一起,综合考虑农产品国际贸易战略的制定;考虑一国内部不同地区之间的虚拟水贸易,对将虚拟水理论纳入政策体系更具实际意义。 相似文献
972.
973.
制药废水的厌氧生化性评价及UASB处理 总被引:1,自引:0,他引:1
为了处理山东某一药厂的高浓度有机废水,首先采用间歇式实验对山东某一制药厂各主要车间生产废水及综合废水进行厌氧可生化性评价。然后以此为基础,采用两级中温UASB,以某一时期排放的厂区综合废水为处理对象,通过缩短HRT,考察在COD容积负荷的逐步升高下,反应器处理效果的变化。进水COD稀释至10 000 mg/L左右,p H维持在6.8到7.1。在单级UASB最大工程设计容积负荷6 g COD/(L·d)的条件下,经过两级UASB的串联处理,总COD的去除率能达73.5%,出水COD能基本稳定在2 600 mg/L。在这个系统运行时期,产气稳定,出水p H值稳定在7.4到8.0之间,VFA在500 mg/L以下。实验结果表明,两级UASB处理该制药厂废水是可行的。 相似文献
974.
Ying Su Xiulin Wang Keqiang Li Shengkang Liang Guodong Qian Hong Jin Aiquan Dai 《Environmental science and pollution research international》2014,21(17):10067-10082
At present, the monitoring network of China cannot provide sufficient data to estimate land-based pollutant loads that enter the sea, and estimation methods are imprecisely used. In this study, the selection of monitoring stations, monitoring frequency, and pollutant load estimation methods was studied in Qingdao City, a typical coastal city in China, taken as an example. Land-based pollutant loads from Qingdao were estimated, and load distribution, density, and composition were analyzed to identify the key pollution source regions (SRs) that need to be monitored and controlled. Results show that the administrative land area of Qingdao can be divided into 25 sea-sink source regions (SSRs). A total of 14 more rivers and 62 industrial enterprises should be monitored to determine the comprehensive pollutant loads of the city. Furthermore, the monitoring frequency of rivers should not be less than three times/year; a monitoring frequency of five or more times is preferable. The findings on pollutant load estimation with the use of different estimation methods substantially vary; estimation results with the use of ratio-based methods were 10 and 22 % higher than those with the use of monitoring-based methods in terms of chemical oxygen demand (COD) and total nitrogen (TN), respectively. None-point sources contributed the majority of the pollutant loads at about 70 % of the total COD and 60 % of the total TN. 相似文献
975.
Chlorpyrifos is one of the organophosphate pesticides widely used in agricultural practices throughout world. It has resulted in a series of toxicological and environmental problems, such as impacts on many non-target aquatic species, including fish. In the present study, toxic effects of chlorpyrifos on lysozyme activities, contents of IgM and complement C3, and the expressions of IgM and complement C3 at mRNA level in common carp were evaluated by acute exposure of 15 (1/10 LC50) or 75 μg L−1 (1/2 LC50) of chlorpyrifos for 7 d. The results of acute toxicity tests showed that the 96 h-LC50 of chlorpyrifos for common carp was determined to be 149 μg L−1. We also found that chlorpyrifos promoted lysozyme activities at the earlier stages of exposure but inhibited it at the late stages in the serum, hepatopancreas, and spleen of common carp. Furthermore, it was observed that chlorpyrifos-exposure decreased IgM contents in fish serum and spleen while increased it in kidney. No obvious change was found in the contents of complement C3 in fish spleen, while a slight increase of complement C3 was observed in fish serum and kidney after 1 d of chlorpyrifos-exposure. In addition, the results of quantitative real-time PCR showed that IgM and complement C3 expressions were up-regulated at the earlier stage of exposure but down-regulated at later stage. Our results indicate that chlorpyrifos causes immunotoxicity to common carp. 相似文献
976.
977.
A Superiority-Inferiority-Based Inexact Fuzzy Stochastic Programming Approach for Solid Waste Management Under Uncertainty 总被引:2,自引:0,他引:2
A superiority–inferiority-based inexact fuzzy stochastic programming (SI-IFSP) model was developed for planning municipal
solid waste management systems under uncertainty. The SI-IFSP approach represents a new attempt to tackle multiple uncertainties
in objective function coefficients which are beyond the capabilities of existing inexact programming methods. Through introducing
the concept of fuzzy random boundary interval, SI-IFSP is capable of reflecting multiple uncertainties (i.e., interval values,
fuzzy sets, probability distributions, and their combinations) in both the objective function and constraints, leading to
enhanced system robustness. The developed SI-IFSP method was applied to a case study of long-term municipal solid waste management.
Useful solutions were generated. A number of decision alternatives could be generated based on projected applicable conditions,
reflecting the compromise between system optimality and reliability as well as the tradeoffs between economic and environmental
objectives. Moreover, the consequences of system violations could be quantified through introducing a set of economic penalties,
reflecting the relationships between system costs and constraint violation risks. The results suggest that the proposed SI-IFSP
method can explicitly address complexities in municipal solid waste management systems and is applicable to practical waste
management problems. 相似文献
978.
Qingxiang Yang Jing Zhang Wenyu Zhang Zhe Wang Yongsheng Xie Hao Zhang 《Journal of environmental science and health. Part. B》2013,48(3):190-197
In this study, the effects of tetracycline exposure on wheat growth and the microbial community structure in the rhizosphere were investigated under hydroponic culture conditions. Exposure to various concentrations of tetracycline resulted in significant suppression of the growth of wheat roots and shoots, with minimum doses of 0.8 mg L?1 and 4 mg L?1 resulting in inhibition rates of 32% and 15.4%, respectively. Complete inhibition of the growth of these two parts of wheat plants was observed in response to treatment with tetracycline at 20 mg L?1 and 100 mg L?1, respectively. However, the germination of wheat seeds was not sensitive to exposure to tetracycline. The effects of tetracycline exposure on the microbial community in the wheat rhizosphere were evaluated through traditional cultivation and molecular biological analyses. The cultivation results indicated that bacteria were the dominant population, being present in concentrations of 1× 108–2.45× 109CFUs mL?1, although 39% to 87% inhibition occurred in response to tetracycline. The concentration of fungi increased in all tetracycline treated samples to 2.5 to 15.8 times that of the control. The highest concentration of fungi (4.27× 108 CFU mL?1) was observed in response to 60 mg L?1 tetracycline after 15 days of cultivation. In this stage, a large amount of fungal colonies was observed on the surface of the culture solution, the wheat roots became rotted and the plants became atrophic or even died. Molecular biological analysis indicated that the bacterial community structure was significantly different in samples that were exposed to high levels of tetracycline (over 20 mg L?1) than in samples that were exposed to lower concentrations. As the concentration of tetracycline increased, the diversity of the bacteria decreased. Additionally, several dominant sensitive species such as Sphingobacterium multivorum were suppressed by tetracycline, while some resistant species such as Acinetobacter sp. appeared or were conserved. The bacteria population tended to stabilize when the drug concentration exceeded 40 mg L?1. 相似文献
979.
Huan Feng Yu Qian Frank J. Gallagher Meiyin Wu Weiguo Zhang Lizhong Yu Qingzhi Zhu Kewei Zhang Chang-Jun Liu Ryan Tappero 《Environmental science and pollution research international》2013,20(6):3743-3750
Synchrotron X-ray microfluorescence and X-ray absorption near-edge microstructure spectroscopy techniques were applied to Typha latifolia (cattail) root sections and rhizosphere soils collected from a brownfield site in New Jersey to investigate lead (Pb) accumulation in T. latifolia roots and the role of iron (Fe) plaque in controlling Pb uptake. We found that Pb and Fe spatial distribution patterns in the root tissues are similar with both metals present at high concentrations mainly in the epidermis and at low concentrations in the vascular tissue (xylem and phloem), and the major Pb and Fe species in T. latifolia root are Pb(II) and Fe(III) regardless of concentration levels. The sequestration of Pb by T. latifolia roots suggests a potential low-cost remediation method (phytostabilization) to manage Pb-contaminated sediments for brownfield remediation while performing wetland rehabilitation. 相似文献
980.
以鸡粪为发酵原料,采用序批式两相厌氧消化工艺在中温条件(37℃)下对其进行消化处理。分别将水解酸化相和产甲烷相pH值控制在5.5±0.3和7.0±0.3,通过改变进样含固率(TS)研究有机负荷(OLR)对两相消化系统处理鸡粪过程中污染物转化和去除效果的影响。结果表明,水解酸化相出水总有机碳(TOC)、挥发酸(VFAs)和氨氮(NH4+-N)浓度都随OLR升高而升高。VFAs组成相对稳定,其中乙酸占总VFAs浓度的57%~64%,其次为正丁酸和丙酸。产甲烷相出水TOC和VFAs稳定在较低水平,TOC去除率最大达到90%以上。产甲烷相进水氨氮主要以NH4+形式在反应器内不断积累。实验后期产甲烷相生物气中甲烷体积分数维持在64%上,证明两相消化系统在实验条件下良好运行。 相似文献