Comparison of metals extractability from Al/Fe-based drinking water treatment residuals

Recycling of drinking water treatment residuals (WTRs) as environment amendments has attracted substantial interest due to their productive reuse concomitant with waste minimization. In the present study, the extractability of metals within six Al/Fe-hydroxide-comprised WTRs collected throughout China was investigated using fractionation, in vitro digestion and the toxicity characteristic leaching procedure (TCLP). The results suggested that the major components and structure of the WTRs investigated were similar. The WTRs were enriched in Al, Fe, Ca, and Mg, also contained varying quantities of As, Ba, Be, Cd, Co, Cr, Cu, K, Mn, Mo, Na, Ni, Pb, Sr, V, and Zn, but Ag, Hg, Sb, and Se were not detected. Most of the metals within the WTRs were largely non-extractable using the European Community Bureau of Reference (BCR) procedure, but many metals exhibited high bioaccessibility based on in vitro digestion. However, the WTRs could be classified as non-hazardous according to the TCLP assessment method used by the US Environmental Protection Agency (USEPA). Further analysis showed the communication factor, which is calculated as the ratio of total extractable metal by BCR procedure to the total metal, for most metals in the six WTRs, was similar, whereas the factor for Ba, Mn, Sr, and Zn varied substantially. Moreover, metals in the WTRs investigated had different risk assessment code. In summary, recycling of WTRs is subject to regulation based on assessment of risk due to metals prior to practical application.     

Relationship between two consecutive lactations and fat level in persistent organochlorine compound concentrations in human breast milk

An attempt was made to understand how consecutive deliveries and the following lactations have an impact on the organochlorine compound levels detected in human milk. The other goal of the study was to check for a possible dependence between fat content and the levels of the studied compounds in milk samples from the same lactations. 199 milk samples were examined for the presence of p,p'-DDT, p,p'-DDE, p,p'-DDD, alpha-, beta-, gamma-HCH and sigmaPCBs. Moreover, in 87 milk samples the fat content was additionally determined. This study has indicated that, for the mother with a shorter interval between lactations, mean concentrations of the examined compounds were higher in the milk of the first lactation than that of the second. For the other donor whose second lactation began after 2 years, the mean levels of HCB, beta-HCH, p,p'-DDD, and PCBs in her milk were higher during the first lactation. At the same time, the concentrations of p,p'-DDT and p,p'-DDE after the second delivery were slightly higher. The correlation coefficients between the two data sets (fat content in milk, concentrations of the compounds studied in milk) showed no interrelationship between them.     

Comparison of trace element accumulation in Baikal seals (Pusa sibirica), Caspian seals (Pusa caspica) and northern fur seals (Callorhinus ursinus)

Concentrations of 18 trace elements (V, Cr, Mn, Co, Cu, Zn, Se, Rb, Sr, Zr, Mo, Ag, Cd, Sb, Cs, Hg, Tl and Pb) were determined in liver, kidney, muscle and hair of Baikal seals, Caspian seals and northern fur seals. All the three species showed the highest concentrations of Hg, V, Mn, Se and Ag in liver, Cd, Co and Tl in kidney, and Cs in muscle among the soft tissues examined. The highest burdens of Zn, Rb and Cs were observed in muscle, Mo and Ag in liver, and Sb and Pb in hair in all the three species. Concentrations of non-essential elements, Rb, Cd, Cs and Hg, showed significant positive correlations among liver, kidney and muscle, whereas correlation coefficients for essential elements, Mn, Co, Cu, Zn and Se, between the three tissues were generally low for all the species, suggesting that homeostasis controls the concentrations of essential elements but not the non-essential elements in the tissues of these animals. Significant age-dependent increase was found in the concentrations of V, Se and Ag in liver and Hg in liver and kidney of all the three species. Hair concentrations showed significant positive correlations with Zn levels in liver and kidney and Hg in muscle for Caspian seals, Hg in liver and kidney for Baikal seals, and Pb in liver for northern fur seals. Furthermore, regression analysis using the data in the present study and in the literature showed significant positive correlations between Hg levels in hair, and liver, kidney and muscle for various species of pinnipeds. These results indicate the possibility of using hair samples for monitoring these trace elements in pinnipeds.     

Detection of herbicides in water bodies of the Samambaia River sub-basin in the Federal District and eastern Goiás

Abstract

The objective of this study was to identify and quantify herbicide residues in water samples of rain, cisterns, streams, ponds, springs, semi-artesian wells, dams and a river in the Rio Samambaia sub-basin in the Federal District and eastern Goiás. A total of 287 samples were collected from 20 farms in the sub-basin in the rainy (February, summer) and dry (August, winter) seasons in 2016. Aminomethylphosphonic acid (AMPA, a glyphosate metabolite), clethodim, chlorimuron-ethyl, diuron, fluazifop acid (a fluazifop-p-butyl metabolite and the active ingredient), haloxyfop acid (a haloxyfop-methyl metabolite and the active ingredient), imazamox, mesotrione, metsulfuron, nicosulfuron and pendimethalin were not identified in any water sample. In the rainy season, approximately 99% of the samples contained residues at least one of the evaluated herbicides; in the dry season (, 100% of the samples contained residues of at least one of the evaluated herbicides. When considering only detection frequency, metribuzin, atrazine, clomazone and haloxyfop-methyl were the main herbicides found in the water of the Samambaia River sub-basin. In turn, based on levels higher than the limit of quantification, the main compounds detected were atrazine, clomazone, haloxyfop-methyl and glyphosate. In both seasons, the highest relative concentrations of herbicides for the rainy and dry seasons were found in spring water, 25% and 56%, respectively, and dam water, 23% and 16%, respectively.     

Part II: temporal and spatial distribution of multiclass pesticide residues in lake sediments of northern Greece: application of an optimized MAE-LC-MS/MS pretreatment and analytical method

The development and application of an analytical methodology for the pretreatment and determination of 253 multiclass pesticides, in lake sediment samples, using liquid chromatography coupled with mass spectrometry (LC-MS/MS) are described in this work. Sediments of lakes Volvi, Doirani, and Kerkini, located in northern Greece, were collected in two-time periods (fall/winter 2010 and spring/summer 2011) and analyzed, applying the developed analytical methodology. Microwave-assisted extraction (MAE) was applied to extract the pesticide residues from lake sediment samples. Analytical results were stored, categorized, and visualized using geographical information systems, in order to assess and observe spatial and temporal variations of the pollution. Main pesticides that were detected included the following: amitrole, tebuconazole, phoxim, diniconazole, sethoxydim, temephos, tetrachlorvinphos, pendimethalin, boscalid, disulfoton sulfone, lenacil, propiconazole, cycloxydim, pyridaben, and terbuthylazine. Amitrole, diniconazole, and tebuconazole were found to be common in all three lakes. Lakes Kerkini and Doirani exhibited increased concentrations during the first sampling period (winter 2010) with predominant pesticide classes, triazines/triazoles and organophosphates. Pollution is mainly located near the populated villages of the lakes and the nearby cultivations. During the second sampling period, pesticide concentrations appear lower and located in sediments near the center of the lake. Lake Volvi exhibits increased pesticide concentrations during the second sampling period, temporal and spatial variations and different pesticide profile pattern. Increased pollution occurs near the center of the lake during the first sampling period, mainly comprised by triazines/triazoles and organophosphates. During the second sampling period, the majority of the sediment samples demonstrated a different pesticide profile dominated by unclassified pesticides and triazines/triazoles. Mineralogical analysis of the samples demonstrates that sediments are mainly composed of clay, mud, and sand particles, and they present spatial variations. Near the center of the lakes, sediments appear to be more fine-grained with higher clay content and are more likely to adsorb pesticides.     

The intestinal parasite Pomphorhynchus laevis (Acanthocephala) from barbel as a bioindicator for metal pollution in the Danube River near Budapest, Hungary

Concentrations of As, Al, Ag, Ba, Bi, Cd, Co, Cr, Cu, Fe, Ga, Mg, Mn, Ni, Pb, Sb, Sn, Sr, Tl, V and Zn were analyzed by inductively coupled mass spectrometry (ICP-MS) in the intestinal helminth Pomphorhynchus laevis and its host Barbus barbus. The fish were caught in the Danube river downstream of the city of Budapest (Hungary). Ten out of twenty one elements analyzed were found at higher concentrations in the acanthocephalan than in different tissues (muscle, intestine, liver and kidney) of barbel. Considering the fish tissues, most of the elements were present at highest concentrations in liver, followed by kidney, intestine and muscle. Spearman correlation analyses indicate that there is competition for metals between the parasites and the host. The negative relationships between parasite number and metal levels in organs of the barbel support this hypothesis. The bioconcentration factors for Ag, As, Ba, Bi, Cu, Ga, Mn, Pb, Sr, Tl, and Zn showed that the parasites concentrated metals to a higher degree than the fish tissues. They accumulated the metals As, Cd, Cu, Fe, Ni, Pb, Sr and Zn even better than established bioindicators such as the mussel Dreissena polymorpha as revealed by data from the literature. The results presented here emphasize that acanthocephalans of fish are very useful as sentinels for metal pollution in aquatic ecosystems. Ratio of metal concentrations in the parasites and the host tissues provide additional information. Not including acanthocephalans in accumulation bioindication studies with fishes (as still customarily done) may lead to false results.     

Accumulation of Hg and other heavy metals in the Javan mongoose (Herpestes javanicus) captured on Amamioshima Island, Japan

Concentrations of 22 elements (Mg, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Mo, Ag, Cd, Sb, Cs, Ba, Tl, total Hg (T-Hg), Pb) and organic Hg (O-Hg) were examined in the liver, kidney and brain of the Javan mongoose (Herpestes javanicus) and in liver of the Amami rabbit (Pentalagus furnessi) from Amamioshima Island in Japan. Relatively high levels of T-Hg levels (from 1.75 to 55.5 microg g-1 wet wt.) were found in the Javan mongoose. As for a comparison of hepatic T-Hg concentrations between the two areas, there was no significant difference between the Javan mongoose in Amamioshima and those in the Okinawa islands. In addition, T-Hg levels in the livers of the Amami rabbit were the same as in the livers of other herbivorous mammals. Taken together, it suggested that T-Hg accumulation in the livers of the Javan mongoose was not affected by the environment but by a specific physiological mechanism. The comparison of Hg and other heavy metal accumulations between terrestrial mammals (13 species, 61 individuals) including the Javan mongoose and marine mammals (18 species, 508 individuals) were also discussed.     

Co-composting of distillery wastes with animal manures: carbon and nitrogen transformations in the evaluation of compost stability

The aim of this work was to study the viability of recycling the solid wastes generated by the winery and distillery industry by means of co-composting with animal manures, as well as to evaluate the quality of the composts obtained. Two piles, using exhausted grape marc and cattle manure or poultry manure, respectively (at ratios, on a fresh weight basis, of 70:30), were composted by the Rutgers static pile composting system. Throughout the composting process, a number of parameters were monitored, such as pH, electrical conductivity, organic matter, water-soluble carbon, water-soluble polyphenols, different forms of nitrogen (organic nitrogen, ammonium and nitrate) and humification indices (humification ratio, humification index, percentage of humic acid-like C, polymerisation ratio and cation exchange capacity), as well as the germination index. Organic matter losses followed first-order kinetics equation in both piles, the highest organic matter mineralisation rate being observed with exhausted grape marc and cow manure. On the other hand, the mixture with the lowest C/N ratio, using exhausted grape marc and poultry manure, showed the highest initial ammonium contents, probably due to the higher and more labile N content of poultry manure. The increase in the cation exchange capacity revealed the organic matter humification during composting. In contrast, other humification parameters, such as the humification ratio and the humification index, did not show the expected evolution and, thus, could not be used to assess compost maturity. Composting produced a degradation of the phytotoxic compounds, such as polyphenols, to give composts without a phytotoxic character. Therefore, composting can be considered as an efficient treatment to recycle this type of wastes, due to composts presented a stable and humified organic matter and without phytotoxic effects, which makes them suitable for their agronomic use.     

Relationships and bioaccumulation of chemical elements in the Baikal seal (Phoca sibirica)

Concentrations of Al, Ba, Cd, Cu, Fe, Mn, Mo, Si, Sr, Zn, Ca, K, Mg, Na and P in the livers of Baikal seal, plankton, zoobenthos, and fish, constituting the food sources for the seals, were determined by ICP-MS and ICP-AES. The accumulation of elements in the liver of seals, affected by internal and external (environmental) factors, was assessed by multidimensional (ANOVA, FA) and correlation analyses. FA has enabled identification of abiotic and biotic factors responsible for the accumulation of elements in the livers of Baikal seals. Significant influence of sex and development stage of the seals analysed on hepatic concentrations of some elements was found. The observed differences in element concentrations between pups, males and females could be attributable to the reproductive cycle of this species. ANOVA showed differences in concentrations of Fe, Zn, Cu and Cd in seals from the three separate basins of the lake. BMFs suggest biomagnification of Fe and Zn in the fish-seal trophic link.     

Congener profiles of PCB and a proposed new set of indicator congeners

In this study, a new method for calculating total PCB and toxic equivalents (TEQ) of coplanar PCB (Co-PCB) was proposed, called the 'PCB dual method'. This method analysed various kinds of technical PCB, samples contaminated by technical PCB and byproduct PCB. In the PCB dual method, a data set of 15 indicator congeners was utilized for the calculations, having IUPAC nos. #3, #8, #28, #52, #77, #101, #105, #118, #126, #138, #153, #180, #194, #206 and #209. The 15 congener set was chosen from the major congeners, determined by HRGC/HRMS analysis, in 18 technical PCB, Kanechlor, Aroclor, Clophen and Chlorofen, and 20 other samples, such as indoor air, flue gases, emission gases, municipal solid waste (MSW), ash and sealant. To obtain total PCB and TEQ of Co-PCB, the intermediate sum for the concentration of the 15 congeners was multiplied by each multiplication factor. As a result, we obtained the average factor used to calculate total PCB in technical PCB and other samples. For technical PCB, the factor was 3.01, while for indoor air samples, flue and emission gases, MSW, ash and sealants, the factors were 3.92, 4.16, 3.68, 4.52 and 4.77, respectively. Moreover, the factor used to calculate the TEQ of Co-PCB in Kanechlor and other source samples were also obtained. The factors for Kanechlor, indoor air samples and emission gases from a cement plant were in the order of 10(-5), while the factor for flue gases in a MSW incinerator was in the order of 10(-3). These data were valuable for the rough estimation of the TEQ of Co-PCB without separation from other PCB before individual measurements.     

Status and dynamics of the Kobresia pygmaea ecosystem on the Tibetan plateau

This paper provides information about the distribution, structure, and ecology of the world's largest alpine ecosystem, the Kobresia pygmaea pastures in the southeastern Tibetan plateau. The environmental importance of these Cyperaceae mats derives from the extremely firm turf, which protects large surfaces against erosion, including the headwaters of the Huang He, Yangtze, Mekong, Salween, and Brahmaputra. The emphasis of the present article is on the climate-driven evolution and recent dynamics of these mats under the grazing impact of small mammals and livestock. Considering pedological analyses, radiocarbon datings, and results from exclosure experiments, we hypothesize that the majority of K. pygmaea mats are human-induced and replace forests, scrub, and taller grasslands. At present, the carrying capacity is increasingly exceeded, and reinforced settlement of nomads threatens this ecosystem especially in its drier part, where small mammals become strong competitors with livestock and the removal of the turf is irreversible. Examples of rehabilitation measures are given.     

Linking valve closure behavior and sodium transport mechanism in freshwater clam Corbicula fluminea in response to copper

Sediment geochemical technique was employed to assess how the sediment records reflect the environmental changes of Jiaozhou Bay, a semi-enclosed bay adjacent to Qingdao, China. In the past hundred years, Jiaozhou Bay has been greatly impacted by human interventions. A dated core sediment by 210Pb chronology was analyzed for trace metals including Li, Cd, Cr, Pb, Cu, Ni, Co, Zn together with C, N, P and BSi. Based on the research, the development of Jiaozhou Bay environment in the past hundred years can be divided into three stages: (1) before the 1980s characterized by relatively low sedimentation rate, weak heavy metal pollution and scarce eutrophication; (2) from the 1980s to 2000, accelerating in the 1990s, during which high sedimentation rates, polluted by heavy metals and the frequent occurrence of red tide; (3) after 2000, the period of the improvement of environment, the whole system has been meliorated including the heavy metal pollution and hypernutrification.     

中国固体废物法规体系框架分析

固体废物污染与其它环境污染不同,具有综合性、长期性和潜在性。固体废物管理更为强调综合利用和全过程管理,必须通过立法建立科学完善的法律制度来加强固体废物的管理。有关固体废物污染防治的法律、法规、部门规章、地方法规和环境技术标准构成了固体废物法规体系的基本框架。在系统分析现有固体废物法规中存在的问题的基础上,对固体废物管理的法规框架进行了探讨。通过立法,以“统一协调,分工负责”的原则规范各部门对固体废物的管理职能。还强调通过立法、健全监督机制、从法律上限制个人对行政权的滥用、制订技术政策与环境技术标准。除了行政责任外,论文还着重强调了环境违法者的民事责任和刑事责任。     

Seasonal variation and local distribution of metals in the seagrass Halophila stipulacea (Forsk.) Aschers. In the Antikyra Gulf, Greece

Accumulation of Fe, Pb, Zn, Cu, Cd, Na, K, Ca and Mg concentrations by the seagrass Halophila stipulacea (Forsk.) Aschers. was studied at eight stations of the Antikyra Gulf (Viotia, Greece). This area was of interest because the contribution of bauxite to the mineral substrate and the discharge of an aluminium factory's wastes in it. Fe, Zn and K concentrations showed a significant seasonal variation with the same pattern (maximum mean value in summer and autumn), unlike Cu, Na and Mg concentrations which showed the opposite pattern. The observed patterns were mainly attributed to the dependence of metal concentrations in the plant on the tissue-age, the growth dynamics of the seagrass and the environment. All metal concentrations in the plant present uniform distribution in the inner part of the Gulf. The leaves of H. stipulacea accumulated higher Zn, Na, K and Mg concentrations than the stems, roots and rhizoids. There was a positive correlation between Cu, Zn, Cd and Na concentrations in the above-ground and below-ground plant parts.     

Mathematical modeling of biofiltration in activated pine-bark charge of a biofilter

Aim, Scope and Background Human economic activities cause emissions of various pollutants of an organic nature: butanol, butyl acetate, methanol, formaldehyde, phenol, benzene, toluene, xylene, etc. These compounds are emitted to atmosphere by various enterprises of food, chemistry, wood processing industries, from transportation means, agricultural enterprises, etc. Therefore, when purifying air from these pollutants, it is necessary to apply efficient and inexpensive air purification methods. In this dimension, the biological air purification is chosen from all possible air cleaning methods. An experimental biofilter with the activated charge of pine bark was developed at the Department of Environment Protection of the Vilnius Gediminas Technical University. In the course of the experimental investigation, it was determined that this air purification method is efficient. Filter efficiency, when purifying air of volatile organic compounds (butanol, butyl acetate and xylene), to a great extent, depending on the nature and concentrations (up to 100 mg/m3) of pollutants injected, might go up to 70-98%. The mathematical model of the biofilter was developed based on the research results and fully taking into consideration physical, chemical, and biological processes going on during its operations. Main Features The aim of this article is to determine biodegradation constant , absorption capacity , and half empiric expressions of filter efficiency. Knowing this, it is possible to find out the dependence of the filter efficiency on the operational parameters of the filter (i.e. on the concentrations and the height of biocharge of the initial pollutants (butanol, butyl acetate, xylene) fed through it). Conclusions With the help of mathematical modeling, the biodegradation constants and absorption capability of volatile organic compounds (butanol, butyl acetate, and xylene) fed into the biofilter charged with the activated pine bark and used for the cleaning of volatile organic compounds, as well as the efficiency of the biofilter in half empiric expression, have been established. It has been discovered that the constant of pollutant biodegradation is a value inverse to the time during which the amount of pollutants in the filter becomes times higher. It is rather complicated to carry out theoretical calculation of the biodegradation constant at a molecular level, therefore this constant has been established based on the results obtained in the course of research. The equations describing pollutant dynamics in the filter charge and the air cleaning processes going on in it have been derived from diffusion equations in a mobile medium. The modeling helped to find out the absorption capacity of the examined pollutants, which by its numeric value is equal to the volume unit of the absorbed gas amount. The latter factor, the same as the biodegradation constant, was determined basing on the experimental results. Mathematical modeling brought a range of formulas expressing dependences of each pollutant's efficiency on its initial concentrations and filter charge height. Recommendation /Outlook. Based on the experimental data, a mathematical model has been developed which will allow the measuring of the filter efficiency not only with regard to the absorption and biodegradation of the pollutants under examination, but also with regard to other pollutants and their compounds, etc., having an impact on the filter performance. The results of the mathematical modeling have revealed that the modeling of processes going on in the filter is much simpler than isthe performance of long and costly experiments. The developed mathematical model makes it possible to measure the filter efficiency at the present moment.     

Report from the Symposium on Air Quality Criteria

Neither time nor space permitted full reporting of the Symposium on Air Quality Criteria, held June 4-5, 1968, in New York City. The Symposium was sponsored by the Air Pollution Control Association, the American Industrial Hygiene Association, the American Petroleum Institute, and the Industrial Medical Association and its educational affiliate, The Occupational Health Institute.

Published here are excerpts from, or author’s abstracts of, the eight principal papers presented at the Symposium.

Not included are the prepared discussions which followed the delivery of the papers.

A full proceedings, including prepared discussions, general discussions, and summation, will be published in the September issue of the Journal of Occupational Medicine, 55 E. Washington Street, Chicago, Illinois 60602.     

Air pollution records on selenite in the urban environment

Black crusts (BC) on selenite, i.e. gypsum stone used in buildings and monuments in the city of Bologna (northern Italy) have been studied.The crusts have been compared with genetically identical ones encountered on gypsum outcrops in the area surrounding the same city, in a relatively clean rural environment.Because of gypsum's high solubility, also in the past, BC began to form and embed particles of atmospheric aerosol as soon as the stone was used in construction, even though the SO₂ levels in the air were probably much lower than today. Unlike other types of stone (sandstone, limestone, marbles), selenite is currently undergoing a deceleration of dissolution processes, following the acidification of the environment caused by industrialisation. For this reason the BC on selenite are older (up to 580±45 yr), thicker (up to 4 cm) and far more stable than those encountered on other types of building stones used in the same area.The BC are stratified: at the base, in contact with the stone, the crust contains numerous prismatic black particles originating from wood combustion; immediately above the base layer these particles progressively increase; finally, in the outer part of the crust one encounters the characteristic black, spongy spherical fly-ash originating from the combustion of mineral oils.From the chemical point of view, a comparison between urban and rural crusts shows that elements such as C, Si, K, Fe, V, Cr, Ni, Zn, Ga, As and Pb are due to present-day and/or past pollutant sources within the city itself.Moreover, the chemical data from the stratigraphy of the BC show that, while C and K were more abundant in the past than now, elements such as Fe, V, Cr, (Mn, Ni), Cu, (Zn), (Ga), As, Pb characterise recent and current urban atmospheres.     

老港填埋场新鲜渗滤液性质研究

用系列滤膜对老港填埋场2003年3月份新鲜渗滤液进行了梯度分离．并研究了其CODcr、氨氮、TOC、IC、TC、TS、FS、电导率、pH、色度,浊度的变化趋势与不同孔径膜之间的关系。结果表明,随着膜孔径的减小,CODcr、氨氮、TOC、IC、TC、TS、FS、色度、浊度等都有不同程度的降低,但降低不大,说明可溶性部分物质对新鲜渗滤液的污染性贡献最大;电导率、pH则先增大后减小。     

Pathways and products of the degradation of PCBs by the sodium dispersion method

Nine polychlorinated biphenyl (PCB) congeners (2-chlorobiphenyl, 3-chlorobiphenyl, 4-chlorobiphenyl, 2,3,4-trichlorobiphenyl, 2,2',5,5'-tetrachlorobiphenyl, 2,3',4,4',5-pentachlorobiphenyl, 3,3',4,4',5-pentachlorobiphenyl, 2,2',4,4',5,5'-hexachlorobiphenyl, and decachlorobiphenyl) were dechlorinated by the sodium dispersion method (SD) at low temperature (60 degrees C). The dechlorination of 4-chlorobiphenyl was the fastest among the three monochlorobiphenyls. As for the other six congeners, we investigated the major dechlorination pathways. Although reaction selectivity was not very sensitive to the position of the chlorine substituent, the chlorines at the para position were slightly easier to dechlorinate than those at the ortho or meta positions. The decomposition rate increased with the total numbers of chlorine substituents. A chlorine situated between two other chlorines showed a high reactivity. When the numbers of chlorines on each of the phenyl rings were different, the reactions occurred on the more substituted ring. In the degradation of 4-chlorobiphenyl at elevated temperature (160 degrees C), we investigated the structures of the polymerized products and whether all the organic chlorinated compounds degraded finally or not. As for the dimers, p-quarterphenyl (QP) and m,p-QP were detected but not o-QP, m-QP, o,p-QP, o,m-QP, or the mono- to tetra-chlorinated QPs. Compounds with a molecular weight of 534.4183 or 758.6713 were detected. They were considered to have C40H54 or C56H86 as their molecular formula. The compounds were most probably the polymerized products resulting from coupling of hexadecane or two hexadecanes and two phenylcyclohexadienes. It was thought the dechlorination and the polymerization were the main reactions. All of many detected compounds were hydrocarbons without chlorines, and no peaks originating from organic chlorinated compounds were observed by mass spectroscopic (MS) methods.     

Integrating remote sensing and local vegetation information for a high-resolution biogenic emissions inventory--application to an urbanized, semiarid region

This paper presents a methodology for the development of a high-resolution (30-m), standardized biogenic volatile organic compound (BVOC) emissions inventory and a subsequent application of the methodology to Tucson, AZ. The region's heterogeneous vegetation cover cannot be modeled accurately with low-resolution (e.g., 1-km) land cover and vegetation information. Instead, local vegetation data are used in conjunction with multispectral satellite data to generate a detailed vegetation-based land-cover database of the region. A high-resolution emissions inventory is assembled by associating the vegetation data with appropriate emissions factors. The inventory reveals a substantial variation in BVOC emissions across the region, resulting from the region's diversity of both native and exotic vegetation. The importance of BVOC emissions from forest lands, desert lands, and the urban forest changes according to regional, metropolitan, and urban scales. Within the entire Tucson region, the average isoprene, monoterpene, and OVOC fluxes observed were 454, 248, and 91 micrograms/m2/hr, respectively, with forest and desert lands emitting nearly all of the BVOCs. Within the metropolitan area, which does not include the forest lands, the average fluxes were 323, 181, and 70 micrograms/m2/hr, respectively. Within the urban area, the average fluxes were 801, 100, and 100 micrograms/m2/hr, respectively, with exotic trees such as eucalyptus, pine, and palm emitting most of the urban BVOCs. The methods presented in this paper can be modified to create detailed, standardized BVOC emissions inventories for other regions, especially those with spatially complex vegetation patterns.