Calculated and measured values of liquid water content in clean and polluted environments     

J. Fišák  D. Řezáčová  J. Mattanen 《Studia Geophysica et Geodaetica》2006,50(1):121-130

The relationship between liquid water content (LWC) and visibility (VIS) in a fog was examined by a field measurement of LWC values at a clean location of the meteorological observatory Sodankylä (Finland) and in a polluted region at the meteorological observatory Mile?ovka (Czech Republic). Furthermore, the use of a simple regression fog model to determine LWC from VIS is examined by comparing well-known relationships with the measurement results. The results show that the verbal characterization of environment (clean, mild polluted, polluted) is insufficient to calculate the LWC values from visibility. It is necessary to establish an additional criterion based on quantitative fog characteristics or to determine the site-related equation from the previous LWC and VIS measurement.  相似文献   

Experimental research on adsorption/desorption for petroleum pollutants in the soil in Daqing oilfield     

Xiaoyan LIU Yingli LI Guocheng MAO Jungang LI Chun LI Jingxin SUN Qianya ZHU 《中国地球化学学报》2006,25(B08):260-260

The Daqing oilfield is one of the biggest oilfields in the world. It has been exploited for several decades, which brings serious pollution to local natural environment. The crude oil on ground which is produced in the process of oil production contains various organic pollutants. The petroleum pollutants tend to adsorb, desorb, biodegrade and photolyze and so on in the soil, but adsorption/desorption is a pair of extremely important environment geochemistry behavior. In order to master the rule of petroleum pollutants migration and transformation in the soil environment, and provide scientific evidence for the prevent research project on petroleum pollution treatment in the Daqing oilfield, the chemozem was selected as the experimental sample, which is a kind of representative soil in the Daqing oilfield. The factors affecting adsorbent and desorption＇s characteristics were discussed, including pH of the soil, the concentrations of suspended particulates and temperature. The oscillation-equity was used in the experiment. The mechanism and dynamics process of the adsorption/desorption were researched. The results showed that adsorbing of the petroleum pollutants on the chemozem sediment is a kind of physical adsorption phenomenon. The adsorption function comes from the hydrophobic and sticky character of the petroleum its self. The velocity of adsorption and desorption is almost equivalent, both concentrations of water in the soil are close to the balance in two hours, thus they achieve homeostasis in three hours. The process of adsorption of the petroleum pollutants responses to Herry isothermal model, with increasing pH, concentration of suspended particulates and temperature, the quantity of adsorption show a descending trend. However, desorption is a contrary course of adsorption in the experiment. Due to various influenced phenomena reflect that the soil in the Daqing oilfield has factors, the quantity of desorption shows an ascending trend. These strong adsorption ability to petroleum pollutants.  相似文献   

Surface and adsorptive properties of wood char particles in soil     

Joseph J. Pignatello Dongqiang ZHU Michael Sander Seokjoon Kwon Washington Braida 《中国地球化学学报》2006,25(B08):260-261

Char and soot （black carbon, BC） are highly surface-active materials that can play an important role in contaminant fate and bioavailability in soils and sediments. This report summarizes our research on the influence of adsorbate structure and BC properties on adsorption of organic compounds, and the possible attenuation of BC surface activity by humic substances in the environment. The BC was a maple wood char formed at 400 ℃ in air and under other conditions. The solutes were polar and apolar aromatic compounds. The following points will be discussed. （1） By comparing adsorption to nonporous graphite, it was shown that molecular sieving effects （steric restriction） in the char micropore system occur in the order of increasing substitution on the benzene ring and in the order of increasing fused ring size. （2） By accounting for hydrophobic and steric effects it was shown that aromatic rings substituted with strongly pi-electron-accepting functional groups, such as nitro, undergo pi-pi electron donor-acceptor （EDA） interactions with the pi-donor polyaromatic （graphene） surface of the char. The free energy of adsorption due to pi-pi EDA interactions correlated with the free energy of molecular complexation in chloroform with model compounds representing the graphene surface （napthalene, phenanthrene, pyrene）. （3） A series of chars were prepared of different polarity （O content） but similar surface area and pore size distribution by varying temperature and atmosphere. Single- and bi-solute experiments showed that polar interactions with surface O are not a significant driving force for adsorption of polar compounds. Rather, surface O attracts water molecule clusters that inhibit adsorption of both polar and nonpolar compounds by competition. （4） Aging of char particles in a soil-water suspension strongly reduced char SA and sorption of added benzene. Studies were conducted with dissolved humic （HA） acid, HA-char co-precipitates, Ala＋-HA-char co-flocculates, and soybean oil representing humic lipid components.  相似文献   

Heavy metal concentrations in water and surface sediments of Maharlou Lake, SE of Shiraz, Iran     

Farid Moore Guiti Forghani Tehrani Afshin Qishlaqi Fatemeh Rastmanesh 《中国地球化学学报》2006,25(B08):168-168

The main objective of this study is to evaluate trace metal distribution and identify their sources in the Maharlou Lake. Trace metals （Cr, Co, Ni, Cu, Zn, Cd, Pb） and major elements （A1, Ca, Fe, K, Mg, Mn, Na, P） were investigated in water and surface sediments. There was a negative relationship between the depth of water and heavy metal concentration. Metal concentrations in water and sediment samples show a high variability and decrease in this order： Al〉Fe〉Ni〉Co〉Pb〉Zn〉Cu〉Mn〉Cd. In the northern parts of the lake, especially at the inflow of drains and the Khoshk River of Shiraz City, metal concentrations are higher in both water and sediment samples. In order to assess the heavy metal enrichment in sediment samples, trace metal concentrations were normalized for Al. Except for Mn, all metals are enriched relative to average crust and average sedimentary rocks. Also, the results showed that stations located at the northern coast of the lake, have higher enrichment factors （EF） than the other stations. The results of this study showed that the Khoshk River and other drains are the main pollutant sources of the Maharluo Lake.  相似文献   

Numerical Investigation of Gas Scavenging by Weak Precipitation     

Leiming Zhang  Robert Vet  Diane V. Michelangeli 《Journal of Atmospheric Chemistry》2006,54(3):203-231

A one-dimensional cloud model with size-resolved microphysics and size-resolved aqueous-phase chemistry, driven by prescribed dynamics, has been used to study gas scavenging by weak precipitation developed from low-level, warm stratiform clouds. The dependence of the gas removal rate on the physical and chemical properties of precipitation has been explored under controlled initial conditions. It is found that the removal of four gaseous species (SO₂, NH₃, H₂O₂ and HNO₃) strongly depends on the total droplet surface area, regardless the mean size of droplets. The removal rates also correlate positively with the precipitation rate, especially for precipitation having a mean radius larger than 20 μm. The dependence of the scavenging coefficients on the total droplet surface area is stronger than on the precipitation rate. The removal rates of SO₂, NH₃ and H₂O₂ by precipitation strongly depend on the others' initial concentrations. When NH₃ (or H₂O₂) concentration is much lower than that of SO₂, the removal rate of SO₂ is then controlled by the concentration of H₂O₂ (or NH₃). The removal of NH₃ (or H₂O₂) also directly depends on the concentration of SO₂. NH₃ and H₂O₂ can also indirectly affect each other's removal rate through interaction with SO₂. The scavenging coefficient of SO₂ increases with the concentration ratio of NH₃ to SO₂ if the ratio is larger than 0.5, while the scavenging coefficient of NH₃ increases with the concentration ratio of SO₂ to NH₃ when the ratio is smaller than 1. The scavenging coefficient of H₂O₂ generally increases with the concentration ratio of SO₂ to H₂O₂. Although the Henry's law equilibrium approach seems to be able to simulate gas scavenging by cloud droplets, it causes large errors when used for simulating the scavenging of soluble gas species by droplets of precipitating sizes.  相似文献   

东湖主要点源氮 , 磷负荷的动态变化   总被引：7，自引：1，他引：7  

贺华中 《湖泊科学》1996,8(3):229-234

根据1990～1992年对武汉东湖水果区几个点源的监测研究,并通过对1982年和1992年入湖氮、磷量的比较,认为武汉东湖富营养化主要在于含氮、磷生活污水的排入;东湖的氨氮污染与可溶磷污染较严重。阐述了东湖水质继续向严重富营养化演变的原因,并提出了防治富营养化的建议。  相似文献   

近20年北京晴天紫外辐射的变化趋势   总被引：11，自引：1，他引：11       下载免费PDF全文

白建辉  王庚辰  胡非 《大气科学》2003,27(2):273-280

在对北京晴天1990年1月～1991年12月太阳辐射观测资料进行了详细分析的基础上,得到了计算晴天紫外辐射的计算公式,结果表明,计算值与观测值吻合得比较好,计算值与观测值的最大相对偏差为6.2%,24个月相对偏差的平均值为1.9%.利用此公式计算了北京晴天1979～1998年的紫外辐射,并给出了1979～1998年紫外辐射的变化趋势,发现近20年北京地区晴天的紫外辐射呈下降趋势,并对其产生原因以及影响紫外辐射的各个因子进行了详细分析.  相似文献   

总磷运移二维模型的有限元法   总被引：7，自引：4，他引：7  

马瑞杰  杨天行  刘晓端 《吉林大学学报(地球科学版)》2003,33(2):200-203

水库中总磷的浓度是水库富营养化的重要指标，根据水库水环境条件，给出污染质总磷运移的二维数学模型；采用Galerlom有限元法进行求解，并给制了等值线图，得到水库中总磷的时空变化规律，为防治水库污染、选择最佳处理方案提供科学理论依据。  相似文献   

天然矿物材料修复富营养化水体的实验研究   总被引：13，自引：0，他引：13       下载免费PDF全文

薛传东  杨浩刘星 《岩石矿物学杂志》2003,22(4):381-385

采用底泥掩蔽技术，选取天然红土，添加适量的粉煤灰及石灰粉作为掩蔽覆盖物，对滇池富营养化水体进行现场修复实验。结果表明：用天然矿物材料减小底泥内源营养盐负荷的释放修复富营养化水体的效果良好；红土是有效的底泥覆盖材料，添加粉煤灰和石灰粉有助于消减底泥中TP、TN的释放量，还可提高对藻类等浮游植物繁殖的营养基础和对藻、藻细胞及其胚胎上浮生长的控制效率，最终达到除藻的目的，为滇池及类似湖库富营养化水体的修复提供了崭新的思路。  相似文献   

生活垃圾对环境的污染评价方法探讨   总被引：5，自引：0，他引：5       下载免费PDF全文

张云  刘长礼  张胜  殷密英  宋淑红  郭根秋 《地球学报》2003,24(4):379-384

生活垃圾对环境的污染，主要表现为垃圾渗滤液对地面水、地下水、土壤等的污染。其污染评价涉及污染物指标、污染物标准值的确定和计算模式的建立等内容。本文在总结现行环境指数评价法的基础上，探讨性地提出一套将基于生活垃圾填埋场环境监测技术标准(CJJ／T3037—95)中涉及地面水、地下水、土壤等的相关监测项和垃圾中的其他常见重要污染物，一并确定出的污染评价指标，再根据相关有毒物急性毒性分级，结合阈限值和部分浸出毒性鉴别标准值等分为5类污染指标。并在污染物的标准值确定后，进行对应于5类污染物的不同数学模式计算，得到5个分类污染指数，再比较判别这5个分类污染指数，选出最大者作为总污染指数的组合型评价垃圾污染的方法。经实例应用分析，该方法对各种污染物数据分布情况的适宜性优于现行其他常用方法。  相似文献