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71.
Mobilization Potential of Hydrophobic Organic Compounds (HOCs) in Contaminated Soils and Waste Materials. Part I: Mobilization Potential of PCBs, PAHs, and Aliphatic Hydrocarbons in the Presence of Solubilizing Substances When using an elution procedure for organic pollutants to estimate the leaching behaviour of contamined soils and waste deposits, the influence of organic matter in solids and eluates adequately has to be considered. In batch tests with a solid/liquid ratio of 1:10, various aqueous solutions were composed, the solubilizing effect of which can be attributed to ubiquitous natural compounds (e. g., phospholipids, humic and carbonic acids). These solutions were evaluated in regard to the mobilization of PAHs, PCBs, and aliphatic hydrocarbons in soil and waste samples. The results were compared with batch tests containing sodium dodecyl sulfate (SDS), the properties and applications of which are selected and optimized in order to simulate the chemical interactions between pollutant and solubilizing substances of natural sources. Under alkaline conditions, the part of eluated pollutants was high because of the release of humic substances indigenous to the sample. Low concentrations of phospholipids and humic acid could decrease the mobility of aliphatic hydrocarbons. The extend of HOC mobilization is affected by specific interdependences between solubilizing substances and reactive matter of the samples. For most samples, 5.0 g/L concentrated SDS solution was able to simulate the most effective natural solutizer potential in regard to the mobilization of PAHs, PCBs, and aliphatic hydrocarbons within the system of batch tests. Whereas elution with pure water caused significant deviations in pollutant composition and too low yields, the use of SDS effected à good conformity. Modified in such a manner, the elution procedure can follow DIN 38414 part 4, when loss of pollutants will be minimized; e. g., centrifugation is needed to separate phases. 相似文献
72.
Howard A. Bridgman 《Journal of Atmospheric Chemistry》1991,12(4):299-317
The pH and the concentrations of sulfate, nitrate, ammonia, and calcium in rainwater were measured for two periods of a single midwest rainstorm which occurred over a mesometeorological network in central Illinois on 24–25 July 1979. Regression analysis was used to compare ion concentrations with rainfall amount, and ion balance was used to compare cation and anion concentrations at individual sites. Only the ions SO4
2- and NO3
- show any significant relationship to rainfall amount, decreasing as rainwater amounts increase (r=–0.57 and –0.60, respectively). During the first period of the rainstorm, a sequential sampler measurements allowed the calculation of detailed temporal variations in SO4
2-, pH, and rain rate. SO4
2- decreased, and pH increased as the rate increased and the opposite temporal pattern occurred as the rain decreased at the end of the period. Reasons for these variations are discussed.Research done while a visiting scientist at the Illinois State Water Survey, Champaign, Illinois, U.S.A. 相似文献
73.
74.
75.
大气的严重污染导致雾中溶入SO2。等物质而形成酸雾(AcidFog)。酸雾的研究较少[1~6,8,10]。美国加州南部酸雾pH<3.0,最低1.63,我国仅对贵州的梵净山及四川的峨眉山等地的酸雾进行过研究,其成分多为常量组分[4~6,10]。SO2是大气中重要的污染物,而酸雾中SO2的研究至今未见报道。因此研究雾水中SO2及其他成分具有重要的意义。青岛的6~7月为多雾月份,此时盛行风SSE1,雾多形成于4~8m/s风速时,雾以上午4~8时频率最大,最小频率出现于午后14~16时,青岛海雾最长持续… 相似文献
76.
Several mines in the Witbank coalfield in South Africa are affected by acid mine drainage. This has led to a deterioration
in the water quality in many surface streams. The Loubert Mine is one such mine. Hence, an initial investigation was carried
out to determine the source of acid mine drainage pollution and the associated hydrogeological conditions. The investigation
showed that most of the acid mine drainage is emanating from old opencast workings which have been backfilled. Most of the
water from the backfilled area drains into control reservoirs. Unfortunately their capacity is limited, which means that water
overspills and seeps from them. This water finds its way into a nearby stream, the water of which accordingly has an unacceptably
low pH value and high sulphate content. The proposals advanced to control the problem basically involve inhibiting the amount
of water infiltrating the backfilled opencast area on the one hand and reducing the amount of water entering the control reservoirs
on the other.
Received: 5 March 1997 · Accepted: 17 June 1997 相似文献
77.
为研究温度和盐度对华贵栉孔扇贝免疫相关酶活力的联合效应,采用中心复合设计(CCD)和响应曲面分析法(RSM)进行试验,在实验室条件下研究了温度(19~31℃),盐度(22~38)对华贵栉孔扇贝酸性磷酸酶(ACP)、碱性磷酸酶(AKP)、谷胱甘肽还原酶(GR)三种免疫相关酶活性的联合效应,旨在考察温度与盐度对ACP,AKP和GR活性的影响及华贵栉孔扇贝免疫水平较高时的最佳温度和盐度组合,为华贵栉孔扇贝人工养殖所需条件提供理论基础。结果表明:温度的一次效应和二次效应对ACP,AKP和GR活力影响显著(P0.05);盐度的一次效应和二次效应对ACP,AKP和GR的活力影响显著(P0.05);温度和盐度的交互作用对ACP,AKP和GR活力的影响显著(P0.05)。采用响应曲面法,建立了温度和盐度对华贵栉孔扇贝ACP,AKP和GR活性影响的模型方程,该模型方程决定系数分别为0.986 6,0.981 3和0.957 6(P0.01),预测系数分别为0.934 5,0.888 0和0.738 4,表明该模型可以用于预测华贵栉孔扇贝ACP,AKP和GR活力变化。通过模型优化和验证实验,得到在温度24.30℃、盐度30.55时,ACP和AKP活力达到最小值,分别为170.43,181.74U/mg,而GR活力最大为0.34U/mg,满意度达0.95。 相似文献
78.
The present study investigated the chemical composition of wet atmospheric precipitation in India’s richest coal mining belt.
Total 418 samples were collected on event basis at six sites from July to October in 2003 and May to October in 2004 and analysed
for pH, EC, F−, Cl−, , , Ca2+, Mg2+, Na+, K+ and . The average pH value (5.7) of the rainwater of the investigated area is alkaline in nature. However, the temporal pH variation
showed the alkaline nature during the early phase of monsoonal rainfall but it trends towards acidic during the late and high
rainfall periods. The rainwater chemistry of the region showed high contribution of Ca2+ (47%) and (21%) in cations and (55%) and Cl− (23%) in anionic abundance. The high non seas salt fraction (nss) of Ca2+ (99%) and Mg2+ (96%) suggests crustal source of the ions, while the high nss (96%) and high ratio signifying the impact of anthropogenic sources and the source of the acidity. The ratio of varies from 0.03 to 3.23 with the average value of 0.84 suggesting that Ca2+ and play a major role in neutralization processes. The assessment of the wet ionic deposition rates shows no any specific trend,
however Ca2+ deposition rate was highest followed by and
. 相似文献
79.
The changing chemical composition of cloud water and precipitation in the Western Sudety Mountains are discussed against the background of air-pollution changes in the Black Triangle since the 1980s until September 2004. A marked reduction of sulphur dioxide emissions between the early 1990's and the present (from almost 2 million tons to around 0.2 million tons) has been observed, with a substantial decline of sulphate and hydrogen concentration in cloud water (SO42− from more than 200 to around 70 μmol l− 1; H+ from 150 to 50 μmol l− 1) and precipitation (SO42− from around 80 to 20–30 μmol l− 1; H+ from around 60 to 10–15 μmol l− 1) samples. At some sites, where fog/cloud becomes the major source of pollutants, deposition hot spots are still observed where, for example, nitrogen deposition can exceed 20 times the relevant critical load. The results show that monitoring of cloud water chemistry can be a sensitive indicator of pollutant emissions. 相似文献
80.
1993—2006年中国区域酸雨变化特征及成因分析 总被引:28,自引:0,他引:28
中国气象局酸雨站网始建于1989年,最初仅有22个。1993—2005年,一直维持在85至88个,经2006和2007年两次扩建达到294个站。考虑到资料的连续性,本文是以80多个酸雨观测站有系统观测以来(即近14年)的酸雨观测资料为基础,经过客观统计分析,得出中国酸雨的时空变化特征。总的来说,中国酸雨区主体位于长江以南的广大地区,北方也存在小范围的酸雨区。从全国来看,酸雨发生范围总体上呈扩大趋势,北方酸雨发生范围扩大明显,南方基本保持不变;而且,酸雨污染重灾区由西南逐步转移至华中和华南中部。就酸雨强度而言,1993—1998年是最强阶段,1999—2002年强度有所降低,2003—2006年酸雨强度重又持续加强,到2006年已达到1993—1998年的平均水平;另一个显著特点是北方酸雨强度加强非常明显。对于中国区域降水酸度变化的成因,本文利用中国SO2排放量的变化和大气成分本底站降水化学的监测资料进行了分析和阐述。 相似文献