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891.
Xiaomin Gu Yong Xiao Shiyang Yin Xingyao Pan Yong Niu Jingli Shao Yali Cui Qiulan Zhang Qichen Hao 《Environmental monitoring and assessment》2017,189(10):514
In this study, the hydrochemical characteristics of shallow groundwater were analyzed to get insight into the factors affecting groundwater quality in a typical agricultural dominated area of the North China Plain. Forty-four shallow groundwater samples were collected for chemical analysis. The water type changes from Ca·Na-HCO3 type in grass land to Ca·Na-Cl (+NO3) type and Na (Ca)-Cl (+NO3+SO4) type in construction and facility agricultural land, indicating the influence of human activities. The factor analysis and geostatistical analysis revealed that the two major factors contributing to the groundwater hydrochemical compositions were the water-rock interaction and contamination from sewage discharge and agricultural fertilizers. The major ions (F, HCO3) and trace element (As) in the shallow groundwater represented the natural origin, while the nitrate and sulfate concentrations were related to the application of fertilizer and sewage discharge in the facility agricultural area, which was mainly affected by the human activities. The values of pH, total dissolved solids, electric conductivity, and conventional component (K, Ca, Na, Mg, Cl) in shallow groundwater increased from grass land and cultivated land, to construction land and to facility agriculture which were originated from the combination sources of natural processes (e.g., water-rock interaction) and human activities (e.g., domestic effluents). The study indicated that both natural processes and human activities had influences on the groundwater hydrochemical compositions in shallow groundwater, while anthropogenic processes had more contribution, especially in the reclaimed water irrigation area. 相似文献
892.
893.
溶液中阴离子和腐殖酸对UV/H2O2降解2,4-二氯酚的影响 总被引:2,自引:0,他引:2
研究了UV/H2O2工艺对2,4-二氯酚(2,4-DCP)的去除效果和水中阴离子、腐殖酸对该工艺降解2,4-DCP的影响.结果表明:UV/H2O2工艺可以有效地去除水中2,4-DCP,光降解过程符合一级反应动力学模型;在H2O2投加量为8 mg/L、1个30 W低压汞灯照射下,2,4-DCP在蒸馏水和自来水中反应速率常数分别为0.023 2、0.016 2 min-1;NO-3、Cl-、HCO-3对2,4-DCP光降解有抑制作用,当3种阴离子摩尔浓度为0.5、10.0、20.0 mmol/L时,对2,4-DCP光降解的抑制程度为HCO-3>NO-3>Cl-;腐殖酸在低浓度时,促进光降解反应进行,在高浓度时,2,4-DCP的光降解受到抑制.自来水中的反应速率常数低于蒸馏水中的反应速率常数是由于水中多种阴离子和腐殖酸影响的结果. 相似文献
894.
采取AB型热解两次焚烧(3T控制)和烟气净化处理新技术进行医疗废物无害化处置工艺设计,运行结果表明:该工艺技术能有效地处理医疗废物,具有无二次污染和社会、经济、环境效益好等优点,值得在实践中进一步推广应用。 相似文献
895.
896.
针对西南喀斯特地区典型矿渣中砷、锑的赋存形态及其潜在风险的问题,采用Shiowatana连续提取法提取矿渣中的砷(As)、锑(Sb),分析并揭示As、Sb的赋存特征;结合矿渣的基本理化性质和矿物组成特征,讨论矿渣堆中As、Sb的活动性及其关键影响因素;采用风险评价编码法(RAC)对矿渣中As、Sb的潜在生态风险进行相关评价.结果表明:矿渣中的As主要以铁铝结合态和残渣态的形式赋存;Sb主要以残渣态的形式赋存.As比Sb具有更高比例的铁铝结合态,而Sb比As具有更高比例的碳酸盐结合态.弱酸至近中性矿渣中,Sb的活动性强于As;酸性矿渣中,As的活动性强于Sb.矿渣中As、Sb的潜在风险以中-低风险为主,个别为高和极高风险. 相似文献
897.
探究了次氯酸钙(Ca(ClO)2)预处理对活性污泥厌氧发酵合成中链脂肪酸(MCFAs)的影响,结果表明Ca(ClO)2能显著提高污泥的降解性能,且发酵液中可溶性有机物增量与Ca(ClO)2浓度梯度呈正相关.当预处理浓度为80 mg·g-1时,产出MCFAs浓度达到峰值(5691.9 mg·L-1),是空白组的2.6倍.然而,更高Ca(ClO)2(240 mg·g-1)预处理浓度下其对污泥中的微生物过程(水解、酸化过程)的抑制作用导致MCFAs产出浓度有所降低.本研究为拓展污泥高值化处理技术提供了新思路. 相似文献
898.
Weng HX Yan AL Hong CL Qin YC Pan L Xie LL 《Environmental geochemistry and health》2009,31(3):401-411
Radioactive iodide (125I) is used as a tracer to investigate the fate and transport of iodine in soil under various leaching conditions as well as
the dynamic transfer in a soil–plant (Chinese cabbage) system. Results show that both soils (the paddy soil and the sandy
soil) exhibit strong retention capability, with the paddy soil being slightly stronger. Most iodine is retained by soils,
especially in the top 10 cm, and the highest concentration occurs at the top most section of the soil columns. Leaching with
1–2 pore volume water does not change this pattern of vertical distributions. Early breakthrough and long tailing are two
features observed in the leaching experiments. Because of the relatively low peak concentration, the early breakthrough is
really not an environmental concern of contamination to groundwater. The long tailing implies that the retained iodine is
undergoing slow but steady release and the soils can provide a low but stable level of mobile iodine after a short period.
The enrichment factors of 125I in different plant tissues are ranked as: root > stem > petiole > leaf, and the 125I distribution in the young leaves is obviously higher than that in the old ones. The concentrations of 125I in soil and Chinese cabbage can be simulated with a dual-chamber model very well. The biogeochemical behaviors of iodine
in the soil-cabbage system show that cultivating iodized cabbage is an environmentally friendly and effective technique to
eliminate iodine deficiency disorders (IDD). Planting vegetables such as cabbage on the 129I-contaminated soil could be a good remediation technique worthy of consideration. 相似文献
899.
Pan Jiahua 《中国人口.资源与环境(英文版)》2011,9(2):28-38
The fundamental way of satisfying the basic needs of human development is to secure the basic needs,limit luxurious and wasteful emissions,and ensure the fulfillment of climate targets,so as to achieve intra-and intergenerational equity.In this paper,the author discusses and analyzes a series of challenges that the development has to face,such as poverty elimination,urbanization,and industrialization,and the problems of increased consumption that is brought about by the improvement of living standards;the author distinguishes the stock emission,which does not need annual updating,and the flow emission of regular consumption;the author also defines the standards of energy consumption and carbon emissions that can meet the basic needs.On this basis,the author proposes the concept and method of carbon budget,compares this method with other means,and in particular,studies and analyzes the implications of international equity and sustainability of carbon budget as part of the international climate regime design. 相似文献
900.
Climate change has become a hot topic in international environmental negotiations.For post-Kyoto international climate regime negotiations,many countries have proposed a variety of frameworks to share the emission reduction responsibilities and allocate carbon emission rights,and have tried to quantify the emission reduction obligations of all countries based on the perspectives of international equity and individual equity.In this paper,the authors have distinguished the concepts of carbon emissions rights based on these two perspectives respectively,have analyzed the relationship between carbon emissions per capita and economic development,and have calculated and compared the proportion of cumulative emissions per capita of different countries in history and future,and then authors conclude that emission reduction obligations should be allocated based on each country’s conditions,including historical emissions,development stage,and future demands.Developed countries should take the initiative to significantly reduce their emissions because they have already accomplished their industrialization process.However,developing countries are still in the process of industrialization,which requires more emission rights to meet their development needs.For China,the concept of carbon emissions based on individual equity can be used as a theoretical tool for the allocating the international carbon emissions rights. 相似文献