石墨炉原子吸收分光光度法测定粮食中的铅和镉

研究并建立了石墨炉原子吸收分光光度法测定粮食中铅和镉的方法，用于实际样品的测定，得到了令人满意的结果。     

石墨炉升温程序的干燥技术

石墨炉升温程序的干燥技术吴华李绍南（江苏苏州市环境监测站，苏州２１５００４）石墨炉升温大致分为干燥、灰化、原子化和消除四个程序。然而，以往人们多对灰化技术颇为重视，研究甚多。因为即使测定同一元素，由于试样基体的不同，而其灰化参数的选择也会截然不同〔１...     

石墨炉原子吸收分光光度法测定土壤中镉的不确定度分析

探讨了石墨护原子吸收分光光度法测定土壤中隔的不确定度评价方法．根据测量不确定度的评定理论，以石墨炉原子吸收测定土壤中镉为例，分析了整个测试过程的不确定来源，通过推导计算，给出了扩展不确定度，并为石墨炉原子吸收光度法测量重金属元素的不确定度评价提供一定的参考价值．     

原子吸收光谱法测定废气中的锡

以HNO3和H2SO4进行消解，用火焰原子吸收光度法测定废气固定源中的锡，用石墨炉原子吸收光度法测定废气散源中的锡，方法的准确度达到满意结果。     

巯基棉富集分离水中痕量铅,镉,铜——火焰原子吸收测定法的研究

水中痕量铅、镉、铜的测定一般需采用石墨炉原子吸收法,此法对仪器要求高,耗费大,精密度、准确度相对较差.本文对巯基棉富集后用火焰原子吸收测定上述元素的方法进行了研究,并与蒸发浓缩和石墨炉原子吸收法作了对比.结果证明巯基棉富集——火焰原子吸收法测定水中微量铅、镉、铜能获得满意的结果.     

全自动消解-石墨炉原子吸收法测定土壤中镉的探讨

探讨全自动消解-石墨炉原子吸收法测定土壤中镉的方法。选用硝酸-氢氟酸-高氯酸作为消解体系,采用全自动消解仪对土壤样品进行消解,通过研究干燥、灰化和原子化温度对吸光度的影响,优化出最佳的石墨炉升温程序,依据国标方法 (GB/T17141-1997)石墨炉原子吸收分光光度法测定土壤样品中的镉元素含量。该方法检测土壤国家标准物质GSS-8、 GSS-22、GSS-24等,所得结果与标准值相吻合。方法简便、快速、重现性好、灵敏度高,适用于批量土壤样品中Cd的测定。     

微波消解-石墨炉原子吸收法测定土壤中铊

通过研究土壤消解体系、混合基体改进剂的使用、石墨管类型的选择和标准加入定量过程对测定结果的影响,建立了适用于土壤中重金属铊的微波消解-平台石墨炉原子吸收方法。结果表明,使用HNO_3-HF-H_2O_2消解体系对土壤进行微波消解,石墨炉原子吸收测定过程采用Pd(NO_3)_2/Mg(NO_3)_2混合基体改进剂和平台石墨管,土壤中铊的检出限可达0.05 mg/kg,线性相关系数为0.996,加标回收率在95.0%~105.0%。使用该方法测得的结果与ICP-MS法比较,无统计学差异。改进后的方法具有简单快捷、灵敏度高、重现性好、线性范围广、结果准确等优势,易于推广使用。     

火焰、石墨炉原子吸收法测定地表水中铜和镉

对浓缩火焰原子吸收法和石墨炉原子吸收法测定地表水中痕量铜和镉的结果作了比较。试验结果表明，两种方法测定结果间无明显差异，加标回收率为88．7％～103％，可互相替代，等效使用。     

原子吸收石墨炉手动进样的改进

国产原子吸收石墨炉仪大都以手动进样为主,由于进样位置难以固定,分析精度低,且与操作人员熟练程度有着极大关系。 在工作实践中根据所使用的石墨炉加工制作了一只进样定位器(见图1)(与北二光WFX—1D石墨炉配套使用),方便适用,基本解决了测定精度低的     

石墨炉原子吸收法用Pd基体改进剂测地表水中的Pb

石墨炉原子吸收法用Ｐｄ基体改进剂测地表水中的Ｐｂ李惠兰，牛星梅（南京市环境监测中心站２１００１３）１前言石墨炉原子吸收光谱法是测定环境样品中的痕量元素最有效的方法之一，它比火焰原子吸收的绝对灵敏度高三个数量级，方法简便，通常情况下液体样品可不用予处理...     

Agro-economic evaluation of water resource project--a modeling approach

Feasibility of an irrigation project is evaluated by two criteria viz., reservoir capacity to irrigate its command area and economic returns by incremental crop production versus capital investment for dam construction. The annual water requirement of different crops in the command area is estimated and compared with the availability of water from the dam for irrigation purpose. The annual crop water requirement is estimated as the sum of evapotranspiration for crops and transmission and other losses. Evapotranspiration is estimated by modified Penman formula. Economics of crop production is analyzed by first estimating the monetary value of existing crop production under current rain fed conditions and then estimating the incremental production of irrigated command area for the proposed crop pattern. The proposed cropping pattern is prepared so as to maximize the benefit of crop production and fodder requirement while maintaining a better crop rotation to improve and maintain physical, chemical, and biological conditions of the soil. The dam is to be used for irrigation and water supply only. Command area served by this reservoir will be 76,500 ha. The existing annual agricultural return is Rs. 2995.56 lakhs and with the proposed irrigation scheme, it is estimated as Rs. 1,77,91.90 lakhs. The incremental annual return would be Rs. 1,47,96.35 lakhs i.e., 642.68% increase in annual return.     

Concentrations of dissolved herbicides and pharmaceuticals in a small river in Luxembourg

Urban and agricultural areas affect the hydraulic patterns as well as the water quality of receiving drainage systems, especially of catchments smaller than 50 km(2). Urban runoff is prone to contamination due to pollutants like pesticides or pharmaceuticals. Agricultural areas are possible sources of nutrient and herbicide contamination for receiving water bodies. The pollution is derived from leaching by subsurface flow, as well as wash-off and erosion caused by surface runoff. In the Luxembourgish Mess River catchment, the pharmaceutical and pesticide concentrations are comparable with those detected by other authors in different river systems worldwide. Some investigated pesticide concentrations infringe current regulations. The maximum allowable concentration for diuron of 1.8 μg l(?-?1) is exceeded fourfold by measured 7.41 μg l(?-?1) in a flood event. The load of dissolved pesticides reaching the stream gauge is primarily determined by the amount applied to the surfaces within the catchment area. Storm water runoff from urban areas causes short-lived but high-pollutant concentrations and moderate loads, whereas moderate concentrations and high loads are representative for agricultural inputs to the drainage system. Dissolved herbicides, sulfonamides, tetracyclines, analgesics and hormones can be used as indicators to investigate runoff generation processes, including inputs from anthropogenic sources. The measurements prove that the influence of kinematic wave effects on the relationship between hydrograph and chemographs should not be neglected in smaller basins. The time lag shows that it is not possible to connect analysed substances of defined samples to the corresponding section of the hydrograph.     

Identification of hotspots using different statistical methods in a region of manufacturing plants

Incident electromagnetic radiation hitting the Earth’s surface shows three phenomena as absorptivity, reflectivity and transmissivity where sum of the three is equal to one. The transmissivity is zero when the surface is opaque. There is a strong relationship between absorptivity and emissivity that is explained by Kirchhoff’s Law. Emissivity is managed by the thermal radiation on the Earth’s surface. Thermal radiation related with the heat transfer of the electromagnetic radiation is controlled by passing energy of atoms and molecules. There are different sources of energy other than the Sun such as geothermal activities, volcanoes and manufacturing plants that contributes to the emissivity of the surface. The thermal radiation produced by manufacturing plants contributes to the Earth’s surface temperature as well.In this study, land surface temperatures were estimated by using inverse Planck function from five Advanced Spaceborne Thermal Emission and Reflection Radiometer remote-sensing satellite sensor thermal infrared bands. It is aimed to highlight hotspots related to manufacturing plants in the region of Kocaeli, Turkey. The hotspots are examined statistically with the minimum noise fraction, the independent component analysis, the local Moran’s I index and the Getis-Ord G_i index methods by using land surface temperatures.     

Optimized Coagulation of High Alkalinity, Low Temperature and Particle Water: pH Adjustment and Polyelectrolytes as Coagulant Aids

The Yellow River in winter as source water is characterized as high alkalinity, low temperature and low particle concentrations, which have brought many difficulties to water treatment plants. This study fully examines the optimized coagulation process of the Yellow River by conventional and pre-polymerized metal coagulants, pH adjustment and polyelectrolytes as the primary coagulants or coagulant aids. For all the metal coagulants, polyaluminum chlorides are superior to traditional metal coagulants due to their stable polymeric species and low consumption of alkalinity. The removal of natural organic matter by monomeric metal coagulants can be improved through pH adjustment, which is in accordance with the higher concentration of polymeric species formed at corresponding pH value. With the addition of polyelectrolytes as coagulant aids, the coagulation performance is significantly improved. The effective removal of dissolved organic matter is consistent with high charge density, while molecular weight is relatively important for removing particles, which is consistent with polyelectrolytes as primary coagulants. These results suggest that the coagulation mechanisms in the removal of dissolved organic matter and particles are different, which may be exploited for optimized coagulation for the typical source water in practice.     

Methanogenesis in monogastric animals

Studies of methanogenic bacteria present in monogastric animals are still scarce. Methanogens have been isolated from faeces of rat, horse, pig, monkey, baboon, rhinoceros, hippopotamus, giant panda, goose, turkey and chicken. The predominant methanogen in all except the chicken and turkey is species of Methanobrevibacterium. The chicken and turkey harbour species of Methanogenium. In pig the population of methanogenic bacteria is more than 30 times as dense in the distal colon as in the caecum. This finding is in agreement with the finding that the rate of methane production is much higher in the colon than in the ceacum. The amount of methane excreted clearly seems to depend on the amount of non-starch polysaccharide intake.The directly measured methane production rate in pigs is from 3.3 to 3.8 times lower than the amount expected from stoichiometric estimates. These data, together with data showing that only small net amounts of hydrogen and small amounts of methane are produced in the ceacum and proximal colon where the microbial activity is high, clearly indicate that hydrogen sinks other than methane production are involved in hydrogen removal in the hindgut of pigs and probably also in other monogastric animals.Methane production by monogastric animals is lower than methane production by ruminants. However, methane production by large herbivorous monogastric animals such as horses, mules and asses is substantial (up to 80 l per animal per day). Methane production by rodents and avians is low. In general, methane production by wild animals is lower than methane production by domestic animals. It is concluded that the contribution of monogastric animals to the global methane emission is negligible, as it only represent about 5% of the total methane emission by domestic and wild animals of 80 Tg per year.     

An Application of the Pump-to-Fill Policy for Management of Urban Stormwater

We consider the management of urban stormwater in two connected dams. Stormwater generated by local rainfall flows into a capture dam and is subsequently pumped into a similar sized holding dam. We assume random gross inflow and constant demand. If we wish to minimise overflow from the system then the optimal management policy is to pump as much water as possible each day from the capture dam to the holding dam without allowing the holding dam to overflow. We shall refer to this policy as the pump-to-fill policy. The model is based on the Parafield stormwater management system in the City of Salisbury (CoS) but assumes constant demand instead of level dependent outflow. If there is insufficient water in the holding dam to meet the desired daily demand then all water in the holding dam is used and the shortfall is obtained from other sources. CoS, in suburban Adelaide in South Australia, is recognised in local government circles as a world leader in urban stormwater management. The water is supplied to local industry to replace regular mains water and is also used to restore and maintain urban wetlands. In mathematical terms the pump-to-fill policy defines a Markov chain with a large transition matrix and a characteristic regular block structure. We use specialised Matrix Analytic Methods to decompose the event space and find simplified equations for the steady state probability vector. In this way we enable an elementary solution procedure which we illustrate by solving the modified Parafield problem. The optimal nature of the pump-to-fill policy is established in a recent paper by Pearce et al. (JIMO 3(2):313–320, 2007). The purpose of the current study is to find optimal management policies for urban stormwater systems. Work supported by the Australian Research Council.     

A modular approach to Integrated Assessment modeling

In this paper, we present a new approach to model coupling that probably forms the methodological basis of a new generation of Integrated Assessment models. This approach respects the knowledge and expertise that is embodied in existing models and encourages their gradual evolution. Modularity is the guiding principle. Our approach is distinguished by the way modules are coupled which is based on an interplay of a job control module, a numerical coupling module, and a couple of stand-alone functional modules. The numerical coupling module - the core component - serves to treat the feedbacks between the functional modules. A first implemented example that couples an economic and a climate module by means of a two-phase meta-optimization is presented here. The algorithm and mathematical structure behind are discussed as well as important features such as convergence behavior and reliability.     

Source Release-Rate Estimation of Atmospheric Pollution from a Non-Steady Point Source at a Known Location

The goal is to build up an inverse model capable of finding the release history of atmospheric pollution by using measured gas concentration data at just one location on the ground and identify the factors which affects the accuracy of the model predictions. The problem involves a non-steady point source of pollution at a known location in the atmosphere. This problem of finding the release rate is an ill-posed inverse problem and its solution is extremely sensitive to errors in the measurement data. Special regularisation methods, which stabilise the process of the solution, must be used to solve the problem. The method described in this paper is based on linear least-squares regression and Tikhonov regularisation, coupled with the solution of an advection-diffusion equation for a non-steady point source. The accuracy of the method is examined by imposing normally-distributed relative noise into the concentration data generated by the forward model as well as some real experimental data.     

Impact of Hazardous Exposure to Metals in the Nile and Delta Lakes on the Catfish, Clarias lazera

The impact of metal pollution in the Nile and Delta lakes was studied in Clarias lazera. Lake Edku is grouped as the site highest in metal concentrations. Compared to Lakes Maryût and Edku, the Nile stations displayed lower levels of metal contamination signifying their selection as reference sites. Metals were accumulated most by the liver, less by muscles and least by serum. Iron showed the highest bioconcentration factors (BCF) in liver, muscles or serum compared to other metals. Even after the refinement of the surrounding water, fish seem to uphold the metals that have been previously ingested. Mercury, in particular, seems to eventually reside in muscles rather than in liver. The positive relationship between total serum protein and metal contents may indicate the formation of specific metal-binding proteins. Meanwhile, serum hyperalbuminemia in polluted fish is probably a shock response towards the high stress index induced by metals. The hypothesis that most of serum copper is bound to ceruloplasmin is documented also in C. lazera. Moderate, but not extennsive, exposure to metals was quite stimulatory to liver alkaline phosphatase (AP) biosynthesis. AP could, thus, be considered as a promising bioindicator for assessing sublethal water intoxicosis.     

Statistical zonation of sediment samples using ratio matching and cluster analysis

A zonation technique for sediment samples based upon contaminant ratios of a series of samples is described. The technique is based on the fact that sediment samples of common origin will tend to have similar ratios of concentrations of trace pollutants such as heavy metals, PCBs, etc., despite dilution by variable amounts of inert materials such as silica or calcite. Comparison of these ratios between individual samples yields a matrix of similarity coefficients, which are then analyzed by a hierarchical agglomerative cluster analysis procedure. Sediment samples of similar origin will tend to group together in a single cluster, whereas samples influence by unique factors such as transport patterns or proximity to point source discharges will appear as separate individual clusters. The results of application of this methodology to Great Lakes samples from Hamilton Harbour and Port Hope are presented.