Estimating nutrient loadings using chemical mass balance approach

The river Hindon is one of the important tributaries of river Yamuna in western Uttar Pradesh (India) and carries pollution loads from various municipal and industrial units and surrounding agricultural areas. The main sources of pollution in the river include municipal wastes from Saharanpur, Muzaffarnagar and Ghaziabad urban areas and industrial effluents of sugar, pulp and paper, distilleries and other miscellaneous industries through tributaries as well as direct inputs. In this paper, chemical mass balance approach has been used to assess the contribution from non-point sources of pollution to the river. The river system has been divided into three stretches depending on the land use pattern. The contribution of point sources in the upper and lower stretches are 95 and 81% respectively of the total flow of the river while there is no point source input in the middle stretch. Mass balance calculations indicate that contribution of nitrate and phosphate from non-point sources amounts to 15.5 and 6.9% in the upper stretch and 13.1 and 16.6% in the lower stretch respectively. Observed differences in the load along the river may be attributed to uncharacterized sources of pollution due to agricultural activities, remobilization from or entrainment of contaminated bottom sediments, ground water contribution or a combination of these sources.     

Characterization of humic substances of different origin by means of mass spectrometry and neural networks

Mass spectrometry fingerprinting of humic acids extracted from different soils has been carried out using laser desorption/ionization mass spectrometry (LDI-TOF MS). LDI-TOF MS provides characteristic mass spectra fingerprints for the humic acids of different origin. The information given in the fingerprints was evaluated for natural grouping trends in the samples by neural networks computing tools, such as self-organizing feature map (SOFM). This approach is efficient for recognizing patterns in the humic acids samples independently of their characteristic variability; variability characterizing natural products such as humic substances. The use of multi-layer perceptron artificial neural networks gave a successful classification of the samples.     

Evaluation of the Impact of Long-range Transport and Aerosol Concentration Temporal Variations at the Eastern Coast of the Baltic Sea

Ambient particles vary greatly in their ability to affect visibility, climate and human health. The fine fraction of aerosol is responsible for greater and wider effects on human health; thus, investigation of this fraction is very important. Continuous measurements of PM2.5 (particulate matter below 2.5 μm in size) concentrations at the Preila monitoring station started in 2003. During a period of 2 years, the episodes of high daily and semi-hourly concentrations of PM2.5 were measured. These episodes did not depend on the season or time of day. The substantial role of long-range transport of pollutants to these increases in concentration was shown using chemical and statistical analysis. It was found that most of the severe episodes occurred when air masses came from a specific site besides it was established that air masses of different origin were characterized by different mixing layer depth. Lower mixing depth was observed in air masses characterized by higher observed concentrations at the measuring site and vice versa. PM2.5 concentrations showed diurnal and seasonal variations whose pattern reflected the regional origin of the aerosol. The regional pollution level was evaluated by the statistical analysis of PM2.5 concentrations. The background annual average of PM2.5 mass concentration for the eastern coast of the Baltic Sea was 15.1 ± 0.8 μg m⁻³.     

NUTRIENT MASS BALANCE AND TRENDS,MOBILE RIVER BASIN,ALABAMA, GEORGIA,AND MISSISSIPPI1

ABSTRACT: A nutrient mass balance — accounting for nutrient inputs from atmospheric deposition, fertilizer, crop nitrogen fixation, and point source effluents; and nutrient outputs, including crop harvest and storage — was calculated for 18 subbasins in the Mobile River Basin, and trends (1970 to 1997) were evaluated as part of the U.S. Geological Survey National Water Quality Assessment (NAWQA) Program. Agricultural nonpoint nitrogen and phosphorus sources and urban nonpoint nitrogen sources are the most important factors associated with nutrients in this system. More than 30 percent of nitrogen yield in two basins and phosphorus yield in eight basins can be attributed to urban point source nutrient inputs. The total nitrogen yield (1.3 tons per square mile per year) for the Tombigbee River, which drains a greater percentage of agricultural (row crop) land use, was larger than the total nitrogen yield (0.99 tons per square mile per year) for the Alabama River. Decreasing trends of total nitrogen concentrations in the Tombigbee and Alabama Rivers indicate that a reduction occurred from 1975 to 1997 in the nitrogen contributions to Mobile Bay from the Mobile River. Nitrogen concentrations also decreased (1980 to 1995) in the Black Warrior River, one of the major tributaries to the Tombigbee River. Total phosphorus concentrations increased from 1970 to 1996 at three urban influenced sites on the Etowah River in Georgia. Multiple regression analysis indicates a distinct association between water quality in the streams of the Mobile River drainage basin and agricultural activities in the basin.     

流动注射-氢化物发生-原子吸收法测定土壤中微量砷

用混酸消解土壤试样，用体积分数为20％的盐酸作酸介质，质量分数为1．5％的硼氢化钾作还原剂，体积分数为1％的盐酸作载液，采用流动注射-氢化物发生三-原子吸收法定量测定土壤中的微劈砷。通过实验确定，在原子化温度为920℃、土壤中共存元素含量低于5mg／kg时对测定无干扰。该方法的榆出限为0．5μg/L，线性范嘲为5～100μg/L．相对标准偏差为0．89％，平均回收率达98．99％：     

An earthquake disaster in Turkey: an overview of the experience of the Israeli Defence Forces Field Hospital in Adapazari

On 17 August 1999 at 3:04 a.m., an earthquake of 7.4 magnitude (Richter scale) struck the Marmara region in Turkey. The city of Adapazari suffered 2,680 fatalities with approximately 5,300 injured. The Israeli Defence Forces (IDF) field hospital arrived at Adapazari, on day four after the quake. The team consisted of 102 personnel. The field hospital acted as a secondary referral centre. A total of 1,205 patients were treated in the field hospital between day four and day 14 of the earthquake. The frequency distribution of the medical problems seen in the field hospital was 32 per cent internal medicine, 13 per cent general surgery including plastic, 21 per cent orthopaedic surgery, 23 per cent paediatric disease, 10 per cent obstetrics and gynaecology and 1 per cent major psychiatric disorders. A mean number of 35 patients per day were hospitalised in the field hospital for between 24 hours to one week. The rapid establishment of the field hospital enabled the local medical facilities to 'buy time' in order to organise and restore surgical and hospitalisation abilities in this disastrous situation.     

An Overview of Sediment Organic Matter Records of Human Eutrophication in the Laurentian Great Lakes Region

The isotopic and molecular compositions of organic matter buried in lake sediments provide information that helps to reconstruct past environmental conditions and to assess impacts of humans on local ecosystems. This overview of sedimentary records from the North American Great Lakes region describes examples of applications of organic geochemistry to paleolimnological reconstructions. These lakes experienced a succession of human-induced environmental changes that started after completion of the Erie Canal in 1825. Agricultural deforestation in the mid-nineteenth century released soil nutrients that increased algal productivity and caused an associated increase in algal biomarkers in sediment records. Eutrophication that accompanied magnified delivery of municipal nutrients to the lakes in the 1960s and 1970s created excursions to less negative δ¹³C values in sediment organic matter. Increased organic carbon mass accumulation rates mirror the isotopic evidence of eutrophication in the Great Lakes.     

油田采出水过滤进水中不同粒径悬浮物的质量分布

采用已知孔径的微孔过滤器,对油田采出水的过滤进水进行了筛分,分析了悬浮物的质量浓度,并同步测定了颗粒体积浓度和几何特征值。除了D[v,0.5]具有指标性意义外,粒度分析结果并不能完全代表过滤等工艺的分离精度。悬浮物几何特征值、体积浓度和质量含量降低率不是同步的,其中质量浓度降低幅度最小。当粒径小于4μm的悬浮物质含量超过3mg/L时,难以被目前普遍采用的过滤工艺去除。应选择与膜过滤类似的更精密的工艺技术,才能最终达到采出水回用标准。     

深部岩体分区破裂化模拟试验模型几何尺寸的确定

为了揭示深部岩体在开挖时所发生的一系列变化情况,需要进行模拟试验研究。简要介绍了深部岩体在开挖洞室或巷道时发生的分区破裂化现象及其发展规律。根据分区破裂化力学现象、模拟试验背景和试验加载条件,运用弹性力学的基本理论,通过分析与计算,确定了采用b/a≥10作为模型几何参数的选取原则。在实验室条件下,可以采用石膏半径b=1 000 mm,钻孔半径a=100 mm的圆柱体模型来模拟深部岩体的分区破裂化现象及其规律。     

Evaluation of Mass-Transfer Coefficient of Free Fall – Cascade-Aerator

The mass-transfer coefficient of a free-fall cascade-aeratorunit of 15 million litres per day was evaluated for its efficiency in the removal of a class of volatile organics, the trihalomethanes(THMs). These compounds are carcinogenic and occur as a resultof chlorination of natural waters. Due to the volatile nature ofthe THMs, the efficiency of aeration as a potential techniquefor their removal has been studied. The principle behindaeration is gas-transfer, according to which the gas-liquidinterface is hypothesized to consist of a gas and liquid filmthrough which gas is transferred by molecular diffusion untilequilibrium is attained. The overall mass transfer coefficient(K _L) of the aerator considering oxygen as the reference compound, was found to be29.3 hr^-1 for THMs.