All posts by simiecoind

Abstract:
In the quest for efficient and economical water use and the optimization of land footprint needed in water production, membrane bioreactors (MBR) are leading the way. In this article, we look at how the membranes in a MBR work, and show some construction developments in this sector of water industry. Secondly the article discusses a completely new and extremely environmentally friendly module cleaning technology. This technology has meanwhile been successfully tested in different pilot units for example in cooperation with Darmstadt University of Technology.

Abstract:
The recent research demonstrates that we spent indoor more than 80% of our time, or in case of child and old persons even 85-90%. Thus, the indoor air quality become a very important problem, a highly attention being accorded to find out the sources of pollution in order to reduce as much as possible the pollution in the indoor air. Polyvinyl chloride (PVC) is a product used on a large scale to produce a large variety of products used in buildings construction (windows, doors, floors, paints, fittings, etc.) but also for household assets (vessel, cling film, etc.) without an important effect on human health; uses of PVC products presents problems due to the presence of vinyl chloride monomer absorbed in the material which is slowly desorbed into air and further in the human body were can generate a large variety of manifestations, from simple sensitivity to diverse cancer forms. Concerns to reduce the monomer quantity from PVC products are since ’70, the producers having established maximum concentrations of polymer in their products. In the last years, due to the large scale usage of PVC in construction as well as due to the measures for building energy efficiency trough reduction of air exchange with outdoor, were generated conditions to accumulate, especially in the new buildings, new toxic compounds, including vinyl chloride. The vinyl chloride concentration in the indoor air, depending on the condition, can rise from tenths to hundred or even thousands of µg/m3. The present paper presents the results of the research activities conducted to establish a method to determine the vinyl chloride from indoor air. The methods performance parameters: LOD – 20,3µg/m3, LOQ – 31,1µg/m3 , bias -5,6%, repeatability – 1,31% and recovery 92,3% allow the method to be used for concentrations higher then 30-40 µg/m3; in order to determine vinyl chloride concentrations lower then 10µg/m3 the method sensibility should be improved.

Abstract:
By air pollution we mean the presence of certain substances in the atmosphere that are different from the normal composition of air and depending on their concentration and time of action lead to human health disorders, affect the flora and fauna, or alter the human living environment. An amount of pollutants discharged into the atmosphere is subjected to a dispersion process that lowers the concentration of pollutants as a function of distance from the source. Concentrations of heavy metals in the snow can be an indicator of air pollution in urban areas, also giving us indications on the origin of pollution. We compared the concentrations of heavy metals in the snow with the background levels to find out if they could be used as an effective indicator of urban air pollution. Samplings were carried out at road intersections in the center and peripheral areas of Bucharest to determine the influence of road traffic and industrial areas on the air pollution levels. Concentrations of copper, lead and cadmium were determined during sessions of sampling in various locations with low or high traffic density and at different distances from sources of industrial pollution. The concentrations of heavy metals in the snow in peripheral areas were clearly higher as compared with the concentrations in the inner city, as they were influenced by local pollution due to the industrial areas nearby the city, as well as due to the influence of wind on the dispersion of pollutants. The concentrations of copper were generally higher at road intersections with high traffic density as compared with sites of low traffic. This could be due to different driving style, especially braking, as the cars brakes are a major source of pollution with copper. In contrast, the cadmium and lead concentrations remained almost constant regardless of traffic intensity. For cadmium there were found relatively high concentrations even at the road intersections of low traffic. This indicates that, beside the traffic, there may be other important sources of pollution with cadmium. Thus we can conclude that the concentrations of heavy metals in the snow are a reliable guide for the degree of air pollution and can be used as a simple and effective indicator of urban air pollution.

Abstract:
Industrial activities cause important environmental changes. It is relevant to observe that the impact of industrial activities on the environment depends on the type of technological process and on the product that is obtained, or on the efficiency of pollution control technologies. A known source for environmental pollution in urban areas or at the workplace is noise. Sound pressure level produces harmful effects on human health. There are several studies that have investigated noise pollution determining the World Health Organization to warn, to raise awareness and to promote actions against noise pollution. This paper aims to introduce innovative systems that absorb and attenuate the noise from industry, urban or extra-urban environment efficient and sustainable based on composite made by recycling solid waste. Research regarding absorptive properties of new types of ecological composite materials, composed of reinforcement materials from various wastes is presented in this paper. Are presented research on the absorbing properties of new types of ecological composite materials, which are based on use as reinforcement material of various wastes, which can affect the environment. Absorption sound capacity for new composite materials varies depending on the proportion and of the nature of the waste that is used. Both the absorbtion capacity for each composite materials represented by the absorbtion coefficient and the influention of the reinforcement material are presented in this paper. Thus the worldwide was taken a series of measures to reduce noise, as in the environment, and jobs.Upon joining the EU, our country is required to align the relevant legal provisions that are regulated by a series of measures to limit noise.

Abstract:
In an economy increasingly globalized a country’s energy strategy is done in the context of changes and developments taking place worldwide. Due to increasing energy demand, energy has developed rapidly without the problem of environmental protection. Total energy demand in 2030 will be around 50% higher than in 2003. The current world energy situation compel mankind to find new energy sources in order to replace fossil fuels currently used widely. It is considered that in perspective, energy from biomass will be ranked second only to energy from fossil fuels. Special attention was given to recovery of the waste and biomass burning from the perspective of preserving natural resources and reduce the amount of waste generated. The quality criteria for the recovery of waste are usually connected to the structural properties of the residue and the content of hazardous substances and the amount of unburned fuel or the solubility of heavy metals, etc. This paper presents the results of same laboratory tests on different samples of coal and waste mixed blends of biomass and small clay. Test samples were subjected to specific laboratory solid (moisture, ash, elemental analysis, calorific value) necessary for evaluating and reporting CO2 emissions in accordance with the law. Analytical investigations were performed to highlight the following aspects: the influence of biomass present in the fuel mix to reduce CO2 emissions; the use of biomass mixed with slag often recover unburned carbon content in the process of energy production; the influence of carbon (total carbon, organic carbon) in calculating CO2 emissions. Following laboratory tests found a better relationship between organic carbon (TOC) and CO2 emissions than total carbon that is present in fuel.

Abstract:
This paper reports determination of bismuth from stationary emission sources using atomic absorption spectrometry with atomisation in a graphite tube (GFAAS) and with generation of hydrides (HGAA). In the last years hydride generation technique (HGAA) became more and more popular in laboratories for estimating trace metals in materials with changeable composition, while the graphite furnace method is often not reliable due to the strong and variable matrix effect and signal splitting. The metals sampling train is used to determine the bismuth in stationary source emissions. The stack gas is withdrawn isokinetically from the source with the particulate emissions collected in a probe and on heated filters and the gaseous emissions collected in a series of chilled impingers with absorption solutions. The filter, absorptions solution and rinsing solutions are recovered for analysis. This paper presents the results obtained by optimizing the method for bismuth determination, respectively the characteristic parameters by atomic absorption spectrometry, with atomisation in a graphite tube (GFAAS) and with hydrides generation technique (HGAA). The limit of detection values obtained were between 1.84 µg/l for method GFAAS and 0.06 µg/l for HGAA. Both methods can be used to determine the concentration of bismuth in fixed emissions sources but with a better accuracy and recovery for HGAAS.

Abstract:
From the potential air pollutants from big urbane areas in the last years special attention is given to particulate maters, which are found among the “six criteria polluters” as they were named by the United States Environmental Protection Agency (EPA) next to the ozone, carbon oxide, nitrogen dioxide, sulphur dioxide and led, due to the risk they can pose to human health and the environment. Of interest to the environment and population health are the PM 10 (particulate matter with an aerodynamic diameter of up to 10 µm) and PM 2.5 (particulate matter with an aerodynamic diameter of up to 2.5 µm) dust fractions, and their monitoring in the environmental air is controlled by the legislation all around the world, the PM 2.5 falling in the category of breathable dusts which can enter and accumulate in the respiratory system at the pulmonary alveolus level, causing serious health problems.The toxic degree of the particulate maters is amplified by the presence in their structure of other harmful chemical compounds from which the most important are heavy metals and PAH-s. The paper presents the test results in 2010, in two monitoring campaigns for PAHs concentration in particulate matter PM 10, PM 2.5 and total suspended particulates in the air, in Razoare, one of the crowded intersections from Bucharest. Thus, the concentration of polycyclic aromatic hydrocarbons in particulate matter in air varies greatly with temperature, the concentrations being 10 -15 times higher than in winter. In terms of distribution in dimensional fractions, the obtained data showed 90% of polycyclic aromatic hydrocarbons are present in PM2.5 fraction, thus indicating the traffic as the priority source of pollution with polycyclic aromatic hydrocarbons in the areas with heavy urban traffic.

Abstract:
In this paper has been studied the utilization of Sphagnum moss peat, natural moss peat and alkaline treated moss peat for the active biomonitoring of air quality from two different areas: Poiana Negrii and Poiana Stampei (Dorna Basin, Romania), during of September – October 2009. The following heavy metals: Pb, Cd, Cu, Mn and Fe, were used as indicators of the level of air pollution in studied areas. Accumulated heavy metals in the exposure sorbents were determined by graphite-furnance electrothermal atomic absorption spectrometry and used for the calculation of the enrichment factor (EF) in each case. The experimental results have show that the efficiency of studied natural materials in the retention of mentioned heavy metals from air depends by the nature of monitorized heavy metal, location and also by the exposure time. On the basis of obtained results, the efficiency of considered low-cost natural materials in active biomonitoring of air quality was considered

Abstract:
An important component of the durable development concept, the environment protection strategy must be thought today in the alternative accepted by almost all world countries: maintain of the global, regional or local ecological balance means a continuous existence.Thus, a continuation, development or even perfecting of the solutions concerning the ecological reconstruction of the Lonea M.E. sterile heap from Jiu Valley is wanted, through field and laboratory research. The main pollutant in the Jiu Valley area is the coal extraction and preparation industry, which constitutes an influence factor on the environment, with negative effects on the soil, water and air. The soil is affected by sterile’ deposit in heaps as a consequence of the underground exploitation activities. By depositing sterile in heaps numerous unbalances have been produced in the area’s flora and fauna, the current project proposes solving these problems in the Lonea M.E. perimeter, which is taken into consideration. We will finally conclude and propose the sollution with the highest efficiency for the ecological reconstruction of the Lonea M.E. sterile heap by using modern methods, pointing out the concrete aspects resulted from the teoretical and experimental studies.

Abstract:
This paper evaluates the effects of the interferents on the method of determination of the As species through stripping voltammetry, using as a working electrode the dropping Mercury electrode. The interferents found in the determination of As through the voltammetric methods can be classified in three categories: the metallic ions which can form intermetallic compounds with As (Cd) that are accumulated on the hanging Mercury electrode; compounds with tensioactive properties which can be absorbed on the surface of the electrode or which can absorb As on their surface; compounds which can determine complexes or precipitates with As (Fe, Zn, Mn). The effected studies led to the following results: iron interferes in the correct evaluation of the result at concentrations higher than 13000µg/l, concentration corresponding to a As(III):Fe 1:4200 ratio; zinc presents interferences over 5000 µg/l values corresponding to a As(III):Zn ratio of 1:1700; the interference of Cadmium is very strong over 150 µg/l values; the tensioactive compounds over 500 µg/l concentrations, corresponding to a As(III) ratio: the tensioactive compounds of 1:167 completely block the determination of arsenic species. The samples were submitted to the UV digestion and then cysteine was added in order to determine the total arsenic, but the results were totally unsatisfactory; mangan proved not to have interference effects even over concentrations of 30mg/l. following these results, as well as the previous studies, we came to the conclusion that the method can be successfully applied on surface and drinking waters or on waters with low metal concentrations, as well as on waters with a reduced organic charge

Abstract:
The elemental concentrations of Ag, Al, As, Au, Ba, Br, Ca, Cd, Ce, Cl, Co, Cr, Cs, Cu, Dy, Eu, F, Fe, Hf, Hg, I, K, La, Lu, Mg, Mn, Mo, Na, Nd, Ni, Rb, Sb, Sc, Se, Sm, Sr, Ta, Tb, Th, Ti, U, V, W, Yb, Zn, and Zr in airborne particulate matter (PM10), deposited dust, and tap water samples collected inside a phosphate fertilizer plant in Romania have been determined by Instrumental Neutron Activation Analysis (INAA). In addition, X-Ray Fluorescence Analysis (XRFA) was used to determine S, and also Ba, Mn, and Ti in airborne particulate mater. These results were compared with permissible levels given by the Romanian norms for chemical pollutants in the workplace atmosphere and potable water. All values were below the maximum permissible levels

Abstract:
Many toxic xenobiotics entering aquatic environments exert their effects through redox cycle. Oxidative stress, incorporating both antioxidant defenses as well as oxidative damage, is a common effect in organisms exposed to xenobiotics in their environment. The present study proposed to evaluate the acute effects of benzenthonium chloride (quaternary ammonium compound with cationic proprieties) and cocamidopropyl betaine (zwitterionic compound with amphoteric proper) on antioxidant defense mechanisms and lipid peroxidation in Cyprinus carpio organs (liver, intestine, kidneys and gills). We assessed the level of oxidative stress biomarkers (superoxide dismutase – SOD, catalase – CAT, glutathione peroxidase – GPx, glutathione reductase -GR, glutathione S transferase – GST, glucose -6- phosphate dehidrogenase – G6PDH) and the levels of lipid peroxidation – LPO through malondialdehide -MDA of 1mg/l toxic substance nominal concentration after 96h exposure period. LPO and antioxidative enzymatic mechanisms displayed different responses in the investigated tissues. We observed that the action of toxic substances is selective at organs levels. The liver and gills were the most affected by toxic action of both tested surfactants compared with the controls. At liver, gills and kidneys level, after 96h toxic exposure, significant modifications were observed in case of CAT, G6PDH, GPx, GST and Gred. In all organs LPO installation was observed which indicate oxidative damage of tissues induced by accumulation of reactive oxygen species (ROS). The biochemical analysis led to the conclusion that antioxidant enzymes showed deficit in ROS balance at all tissues levels which induce oxidative stress in fish organs.

Abstract:
Lichens are by far the most indicators of the environmental quality, due to their sensitivity to anthropogenic impact. The assessment of environmental quality, has been performed in forest ecosystems located within Bucharest metropolitan area by using epiphytic lichens. A total of 27 lichen species were recorded in the investigated forests, of which some certain lichen species, such as: Candelaria concolor (Dicks.) Ach., Flavoparmelia caperata (L.) Hale, Pertusaria dacica Erichs., and Ramalina farinacea (L.) Ach. were not found within disturbed forests from the studied area. The presence of mentioned lichen species is attributed to an improvement of atmospheric quality. Regarding the number of inventoried lichen species no major differences were recorded in the investigated forests as a function of the distance from Bucharest Municipality. One certain lichen species (Flavoparmelia caperata) which have recorded the highest values of relative abundance have a rather low to intermediate resistance to atmospheric pollution, therefore it has been found within relatively unaffected forestry ecosystems unlike cosmopolitan lichen species which have recorded higher values of relative abundance in proximity of anthropogenic sources. The values of Atmospheric Purity Index has revealed for a majority of investigated forests a rather low environmental quality.

Abstract:
European legislation requires that special aggressive pollutant gases (i.e. NO), must be measured continuously, particularly in locations with the suspected highest load risk. There are a number of oxides of nitrogen, including nitrous oxide (N2O), nitric oxide (NO), nitrogen dioxide (NO2), nitrogen trioxide (N2O3), and nitrogen pentoxide (N2O5), that are referred to collectively as NOx. The two oxides of nitrogen that are of primary concern to air pollution are NO and NO2. The monitoring of NO2 for regulatory purposes requires methods suitable for concentrations measuring in the range relevant for Europe, i.e. 0 – 500 mg/m3, with a sufficiently high accuracy. Different methods have been developed for the measuring of NO2 concentrations, some of which can only measure NO2, while others can also measure NO and/or NOx. These methods are referring either to standard methods or to acceptable one, with simple chemical and physical principles, either to methods based on sophisticated electronic techniques. In this paper are presented certain methods for measurement, monitoring and control of the nitrogen oxides, recommended at international level. Through these methods, can be known the quantity of NOx emissions from ambient air. This is the first step to establish appropriate methods to prevent and reduce air pollution.

Abstract:
Voltammetric behavior of the complex of vanadium with 2,3-dihydroxybenzaldehide in acid buffered solutions in the presence of bromate ions as an oxidant agent has been investigated. It has been established that the analytical signal amplifies by more than one order. The lowest concentration of vanadium determination with an accumulation time of 30 s is 2·10-10 М. The method has been used for determination of vanadium in natural waters.

Abstract:
Thermoelectric power plants are one of the main polluters of the environment. Power plants Nikola Tesla in Serbia burn lignite containing trace metals and radionuclides to a certain extent. To assess environmental contamination due to power plants operation, concentrations of metals and radionuclides were determined in soil samples of surrounding areas. Concentration of major and trace elements were determined using different spectrometry techniques. Gamma-ray spectrometry was used to determine activity concentrations of natural gamma-emitting radionuclides (40K, 226Ra and 232Th) and 137Cs derived from Chernobyl accident. Soil particle size fractions were determined by the traditional pipette method. To determine the correlation between content of metals and radionuclides in soil and soil particle-size fractions the obtained data were subjected to cluster analysis (CA). Resulting dendrogram identified five clusters. Significant correlations were obtained between Cr, Fe and Co; 40K, silt and clay; 232Th, 226Ra and sand. Weak correlation of Cu, Pb, Cd and 137Cs with other parameters indicated their anthropogenic origin in soil samples. Cesium, clay and Mn were grouped into one cluster which indicated the association of this radionuclide with manganese oxides and clay particles. Results obtained by CA confirmed that multivariate analysis is powerful tool for the assessment of origin of stable metals and radionuclides in areas surrounding thermal power plants

Abstract:
This study was realized in order to determine the degree of substances priority/hazardous pollution in the industrial chemical platform of Ramnicu Valcea. Samples were collected in two campaigns, in February and June 2010 and nickel, copper, cadmium, 1,2 dichloroethane, trichlorethylene, 1,2,4 trichlorobenzene and perchlorethylene from water, soil and sediments was analized. The results show that heavy metals in sediments collected from the Olt river, (Priza Olt and Cremenari), had higher concentrations than in National Legislation. Also notice that in all three points, 1,2 dichloroethane, trichlorethylene, 1,2,4 trichlorobenzene and perchlorethylene taking values below the detection method. Concentrations of heavy metals in water were lower than the limits imposed by National Legislation. For organochlorine substances analyzed in three points, an increase of concentration for 1,2 dichloroethane, trichlorethylene and perchlorethylene in sections downstream of the chemical platform of Ramnicu Valcea (Cremenari and Babeni Marcea) to the Priza Olt upstream section of the platform.The concentrations of nickel, copper, cadmium, 1,2 dichloroethane, trichlorethylene, 1,2,4 trichlorobenzene and perchlorethylene in soil samples respect the limits by the Environmental Legislation. In Priza Olt and Cremenari points, were found a degree of accumulation of heavy metals higher compared Babeni Marcea point, located in downstream of wastewater discharges of chemical platform. There was an accumulation of organochlorine in sediments in the three points.

Abstract:
In this paper, are monitored following indicators physics of water in Eforie Nord, Herastrau Mogosoaia Moeciu, Bordei: turbidity, pH, oxygen, conductivity, such variation is made and physical indicators of temperature. To measure this quality indicator of water, we used: turbidimetru portable microprocessor type HI 93 703, oxigenometru portable microprocessor type HI 9146, HI 9214 pH meter type. Natural water quality is determined, in general, all mineral and organic substances, dissolved gases, particulate matter and living organisms present. Conductivity of water is one of the most used indicators to assess the degree of mineralization, water conductivity measurements allow determination of total dissolved salts in water.The concentration of hydrogen ions in water (pH), is an important factor determining the reactivity of water capacity, its aggressiveness, ability to provide water for development of various media organizations. Turbidity is due to solid particles or in the form of colloidal suspensions. It is therefore very important to monitor physical indicators of water.

Abstract:
Pharmaceutical compounds are continually introduced into the environment as a result of industrial and domestic use. Influents and effluents from three municipal waste water treatment plants (WWTPs) with varying waste water treatment technologies and design were analyzed for six anti-inflammatory drugs, an antiepileptic drug and a nervous stimulant during nine months period. The temporal evolution and removal rates in the WWTPs of the pharmaceutical compounds have been studied. Analytical determination was carried out by high performance liquid chromatography (HPLC) with multiwaved detector after sample clean up and concentration by solid phase extraction (SPE). All compounds were detected not only in influents but also in waste water effluents. These findings indicate that several conventional waste water management practices are not effective in the complete removal of pharmaceutical compounds, and their discharges have a large potential to affect the aquatic environment.

Abstract:
The purpose of this paper was to investigate distribution of organic and inorganic contamination in water and sediment in different locations of Saint George Branch -the southern branch of the Danube Delta. Concentrations of dissolved oxygen, nutrients, metals, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), mineral oil were analyzed in water and sediment samples and the results were compared to those obtained in the previous works. Sampling was monthly performed in the period 2009-2011 from seven locations of Saint George Branch from the Danube Delta. The obtained values were evaluated for their compliance with quality standards stipulated in Statutory Order No. 161/2006 of the Romanian Ministry of the Environment and Water Management. In Danube river water, the content of heavy and toxic metals was in most cases below the limits according to the national legislation, only iron values exceed the limit. Concerning organic compounds, mineral oil, DDTs and PCBs periodically were recorded in river water over the limit. In sediment, in some locations, were detected higher concentrations of copper, nickel, mercury, Lindane, PAHs, DDTs and PCBs that exceeded the quality standards according to Romanian legislation transposed from Frame Water Directive 2000/60/EC.

Abstract:
Drinking water produced in water plants almost invariably fulfils the water quality requirements set in European Union Drinking Water Directive (Council Directive 98/83/EC, 1998). However, the DWD requires that water quality should also meet the requirements at the consumer’s tap. When drinking water is distributed through pipelines, biofilms will grow on the inner surface of the pipes and soft deposits (organic and inorganic matter) and several metals will accumulate to the pipelines. Corrosion of household plumbing systems is an important source of trace metals found in tap waters. Significant levels of trace metals could be detected after stagnation of the water in distribution system, especially during night – time. In order to get an overview of the overall current contamination levels of drinking water at the point of consumption were collected and analysed more than 600 samples from cold line-pipe with three different sampling procedures (first draw, fully flushed and randome daytime). A monitoring plan was developed and the content of metals was analyzed from drinking water samples collected directly from consumers and from the municipal distribution network. In the study were correlated data regarding metals concentration in customer’s tap water and materials used in domestic distribution systems in order to investigate influence of materials to the tap water quality.

Abstract:
The paper presents a new analytical method for identifying of chromium, copper and lead from drinking water. Its novelty consists in introducing a selected methyl orange –dye for identification and dozing of three metals. The method is applicable both for drinking and mineral water in which the degree of interaction with other compounds or impurities is relatively low. The three metals are usually qualitatively and quantitatively analysed by standard classical methods: colorimetry or atomic absorption spectrophotometry. But these methods require some reagents, also are energy consuming and have high cost. The new method is cheaper, faster and the colloidal dye can be applied in situ. The method for determination of: chromium, copper and lead from drinkable waters consists in introducing a fixed amount of dye and measuring absorption of the formed metal-dye associates. Most organic dyes are basic or acids compounds and present colloidal association. Their tendency to associate in colloidal micelles was first studied by conductivity. Due to the flat shape their molecules form layered lamellar micelles, resembling like a “package of cards”. Methyl orange is recognized as a colloidal type dye. The intensity of characteristic bands is proportional to the amount of colloid indicator (methyl orange- dye) and number of metal-dye associates present in the system. Thus the concentration of metals in water can be determined. Due its capacity to determine qualitatively and quantitatively the three selected metals in drinking water, the paper presents ecological importance

Abstract:
There is increasing interest in isolation, identification and quantification of polyaromatic sulfur heterocycles (PASH) in view of their importance in environmental forensics, toxicology, geochemistry, etc. Although EU regulations are still in process for this class of compounds, the mutagenic and carcinogenic effects of some PASH compounds determined a major analytical development, all efforts being conducted to a higher level of interest of monitoring water resources and possible soil contamination. Over the past decade, gas chromatography coupled with mass spectrometry was a powerful tool for characterization of PASH compounds in environmental samples. To be able to identify possible water and soil contamination with PASH compounds, a new method was necessary to be developed, to have the opportunity to take action and promote a new step in Romanian environmental protection. For this purpose, we developed a GCMS method using a low resolution mass spectrometer for identification and quantification of some PASH compounds including phenanothro[3,4b]thiophene with mutagenic effect J.Heterocycl.Chem.17(1980)1259).