خيارات البحث
النتائج 1281 - 1290 من 1,540
Occurrence of psychoactive compounds and their metabolites in groundwater downgradient of a decommissioned sewage farm in Berlin (Germany)
2012
Hass, Ulrike | Dünnbier, Uwe | Massmann, Gudrun
PURPOSE: Psychoactive compounds—meprobamate, pyrithyldione, primidone, and its metabolites, phenobarbital, and phenylethylmalonamide—were detected in groundwater within the catchment area of a drinking water treatment plant located downgradient of a former sewage farm in Berlin, Germany. The aim of this study was to investigate the distribution of the psychoactive compounds in anoxic groundwater and to assess the risk of drinking water contamination. Groundwater age was determined to achieve a better understanding of present hydrogeological conditions. METHODS: A large number of observation and production wells were sampled. Samples were analyzed using solid-phase extraction and ultrahigh-performance liquid chromatography–tandem mass spectrometry. Groundwater age was estimated using the helium–tritium (3He–3H) dating method. RESULTS: Concentrations of psychoactive compounds up to 1 μg/L were encountered in the contamination plume. Generally, concentrations of phenobarbital and meprobamate were the highest. Elevated concentrations of the analytes were also detected in raw water from abstraction wells located approximately 2.5 km downgradient of the former sewage farm. Concentrations in the final drinking water were below the limit of quantification owing to dilution. The age of shallow groundwater samples ranged from years to a decade, whereas groundwater was up to four decades old at 40 m below ground. Concentrations of the compounds increased with groundwater age. CONCLUSIONS: Elevated concentrations of psychoactive drugs indicate a strong persistence of these compounds in the environment under anoxic aquifer conditions. Results suggest that the heritage of sewage irrigation will affect raw water quality in the area for decades. Therefore, further monitoring of raw and final drinking water is recommended to ensure that contaminant concentrations remain below the health-based precautionary value.
اظهر المزيد [+] اقل [-]Development of a country-specific CO₂ emission factor for domestic anthracite in Korea, 2007–2009
2012
Lee, Jeongwoo | Kim, Jinsu | Kim, Seungjin | Im, Gikyo | Lee, Seehyung | Jeon, Eui-Chan
INTRODUCTION: Korea has been making efforts to reduce greenhouse gas (GHG) emissions, including a voluntary commitment to the target of a 30% reduction, based on business-as-usual of the total GHG emission volume, by 2020; 2006 IPCC Guidelines provided default values, applying country-specific emission factors was recommended when estimating national greenhouse gas emissions. RESULTS AND DISCUSSION: This study focused on anthracite produced in Korea in order to provide basic data for developing country-specific emission factor. This study has estimated CO₂ emission factors to use worksheet of which five steps consisted according to the fuel analysis method. CONCLUSION: As a result, the average of net colorific value for 3 years (2007∼2009) was 4,519 kcal/kg, and the CO₂ emission factor was calculated to be 111,446 kg/TJ, which is about 11.8% lower than the 2006 IPCC guidelines default value, and about 7.9% higher than the US EPA emission factor.
اظهر المزيد [+] اقل [-]Source apportionment of ultrafine and fine particle concentrations in Brisbane, Australia
2012
Friend, Adrian J. | Ayoko, G. A. (Godwin A.) | Jayaratne, E Rohan | Jamriska, Milan | Hopke, Philip K. | Morawska, L. (Lidia)
PURPOSE: To investigate the significance of sources around measurement sites, assist the development of control strategies for the important sources and mitigate the adverse effects of air pollution due to particle size. METHODS: In this study, sampling was conducted at two sites located in urban/industrial and residential areas situated at roadsides along the Brisbane Urban Corridor. Ultrafine and fine particle measurements obtained at the two sites in June–July 2002 were analysed by positive matrix factorization. RESULTS: Six sources were present, including local traffic, two traffic sources, biomass burning and two currently unidentified sources. Secondary particles had a significant impact at site 1, while nitrates, peak traffic hours and main roads located close to the source also affected the results for both sites. CONCLUSIONS: This significant traffic corridor exemplifies the type of sources present in heavily trafficked locations and future attempts to control pollution in this type of environment could focus on the sources that were identified.
اظهر المزيد [+] اقل [-]Evaluation of adsorption characteristics of an anionic azo dye Brilliant Yellow onto hen feathers in aqueous solutions
2012
Mittal, Alok | Thakur, Vijay | Gajbe, Vibha
PURPOSE AND AIM: Removal of an anionic azo dye Brilliant Yellow has been carried out from its aqueous solutions by using hen feathers as potential adsorbent. MATERIALS AND METHODS: Hen feathers procured from local poultry were cut, washed, and activated. Detailed chemical and physical analysis of hen feathers and its characterization through scanning electron microscopy, X-ray diffraction, and infrared measurements have been made. Procured dye has been adsorbed over under batch measurements and adsorption process is monitored using UV spectrophotometer. RESULTS: Optimum parameters for the adsorption of Brilliant Yellow over hen feathers have been determined by studying the effect of pH, temperature, concentration of dye, and amount of adsorbent. On the basis of Langmuir adsorption, isotherms feasibility of the ongoing adsorption has been ascertained and thermodynamic parameters have been calculated. Attempts have also been made to verify Freundlich, Tempkin, and Dubinin–Radushkevich adsorption isotherm models. It is found that during adsorption, uniform distribution of binding energy takes place due to interaction of the dye molecules and the ongoing adsorption process is chemisorptions. The kinetic measurements indicate dominance of pseudo-second-order process during the adsorption. The mathematical treatment on the kinetic data reveals the rate-determining step to be governed through particle diffusion at 8 × 10−5 M and involvement of film diffusion mechanism at higher concentration at temperatures at all the temperatures. CONCLUSIONS: The developed process is highly efficient and it can be firmly concluded that hen feather exhibits excellent adsorption capacity towards hazardous azo dye Brilliant Yellow.
اظهر المزيد [+] اقل [-]Lethal effects on different marine organisms, associated with sediment–seawater acidification deriving from CO₂ leakage
2012
Basallote, M. D. | Rodríguez-Romero, A. | Blasco, J. | DelValls, A. | Riba, I.
CO₂ leakages during carbon capture and storage in sub-seabed geological structures could produce potential impacts on the marine environment. To study lethal effects on marine organisms attributable to CO₂ seawater acidification, a bubbling CO₂ system was designed enabling a battery of different tests to be conducted, under laboratory conditions, employing various pH treatments (8.0, 7.5, 7.0, 6.5, 6.0, and 5.5). Assays were performed of three exposure routes (seawater, whole sediment, and sediment elutriate). Individuals of the clam (Ruditapes philippinarum) and early-life stages of the gilthead seabream, Sparus aurata, were exposed for 10 days and 72 h, respectively, to acidified clean seawater. S. aurata larvae were also exposed to acidified elutriate samples, and polychaete organisms of the specie Hediste diversicolor and clams R. philippinarum were also exposed for 10 days to estuarine whole sediment. In the fish larvae elutriate test, 100 % mortality was recorded at pH 6.0, after 48 h of exposure. Similar results were obtained in the clam sediment exposure test. In the other organisms, significant mortality (p < 0.05) was observed at pH values lower than 6.0. Very high lethal effects (calculating L[H⁺]50, defined as the H⁺ concentration that causes lethal effects in 50 % of the population exposed) were detected in association with the lowest pH treatment for all the species. The implication of these results is that a severe decrease of seawater pH would cause high mortality in marine organisms of several different kinds and life stages. The study addresses the potential risks incurred due to CO₂ leakages in marine environments.
اظهر المزيد [+] اقل [-]Urbanisation and human health in China: spatial features and a systemic perspective
2012
Li, Xinhu | Wang, Cuiping | Zhang, Guoqin | Xiao, Lishan | Dixon, Jane
BACKGROUND, AIMS AND SCOPE: Current studies have paid little attention to the dynamism in urban spatial expansion and its possible environmental and health effects or to the health effects of rapid urban environmental change at different points along the urbanisation gradient. This study adopts a public health ecology approach to systematically understand the relationship between urbanisation, urban environmental change and human health in China. METHOD: Remote sensing image analysis, based on night light data at five different time periods in recent decades, was used to determine changes to the overall urban area. Through a review of the evidence on the relationships between environmental health, urbanisation and health, we advance a pathway framework for explaining urban human health ecology. The Spearman rank correlation coefficient was used to measure the correlation between disease prevalence and urbanisation level, adding a further dimension to a systemic understanding of urban health. RESULTS AND CONCLUSIONS: Urban areas have been increasing spatially, but unevenly, in recent decades, with medium and small cities also expanding rapidly in the past decade. Urbanisation and urban expansion result in changes to land use/coverage change, the urban environment and the residents’ lifestyle, which result in human health problems. Regions with the highest urbanisation level were more inclined to have a high prevalence of chronic disease in recent decades. An ecological public health approach provides insights into the multiple types of data which need to be routinely collected if human disease is not to become a barrier to social and economic development.
اظهر المزيد [+] اقل [-]An overall risk probability-based method for quantification of synergistic and antagonistic effects in health risk assessment for mixtures: theoretical concepts
2012
Yu, Qiming J. | Cao, Qiming | Connell, D. W.
PURPOSE: In the assessment of health risks of environmental pollutants, the method of dose addition and the method of independent action are used to assess mixture effects when no synergistic and/or antagonistic effects are present. Currently, no method exists to quantify synergistic and/or antagonistic effects for mixtures. The purpose of this paper is to develop the theoretical concepts of an overall risk probability (ORP)-based method to quantify the synergistic and antagonistic effects in health risk assessment for mixtures. METHOD: The ORP for health effects of environmental chemicals was determined from the cumulative probabilities of exposure and effects. This method was used to calculate the ORP for independent mixtures and for mixtures with synergistic and antagonistic effects. RESULTS: For the independent mixtures, a mixture ORP can be calculated from the product of the ORPs of individual components. For systems of interacting mixtures, a synergistic coefficient and an antagonistic coefficient were defined respectively to quantify the ORPs of each individual component in the mixture. The component ORPs with synergistic and/or antagonistic effects were then used to calculate the total ORP for the mixture. CONCLUSIONS: An ORP-based method was developed to quantify synergistic and antagonistic effects in health risk assessment for mixtures. This represents a first method to generally quantify mixture effects of interacting toxicants.
اظهر المزيد [+] اقل [-]Simultaneous immobilization of metals and arsenic in acidic polluted soils near a copper smelter in central Chile
2012
Cárcamo, Valeska | Bustamante, Elena | Trangolao, Elizabeth | de la Fuente, Luz María | Mench, Michel | Neaman, Alexander | Ginocchio, Rosanna
INTRODUCTION: Acidic and metal(oid)-rich topsoils resulted after 34 years of continuous operations of a copper smelter in the Puchuncaví valley, central Chile. Currently, large-scale remediation actions for simultaneous in situ immobilization of metals and As are needed to reduce environmental risks of polluted soils. Aided phytostabilization is a cost-effective alternative, but adequate local available soil amendments have to be identified and management options have to be defined. MATERIALS AND METHODS: Efficacy of seashell grit (SG), biosolids (B), natural zeolite (Z), and iron-activated zeolite (AZ), either alone or in mixtures, was evaluated for reducing metal (Cu and Zn) and As solubilization in polluted soils under laboratory conditions. Perennial ryegrass was used to test phytotoxicity of experimental substrates. RESULTS: Soil neutralization to a pH of 6.5 with SG, with or without incorporation of AZ, significantly reduces metal (Cu and Zn) solubilization without affecting As solubilization in soil pore water; furthermore, it eliminates phytotoxicity and excessive metal(oid) accumulation in aerial plant tissues. Addition of B or Z to SG-amended soil does not further reduce metal solubilization into soil pore water, but increase As solubilization due to excessive soil neutralization (pH > 6.5); however, no significant As increase occurs in aerial plant tissues. CONCLUSION: Simultaneous in situ immobilization of metal(oid) in acidic topsoils is possible through aided phytostabilization.
اظهر المزيد [+] اقل [-]Influence of enumeration time periods on analyzing colonization features and taxonomic relatedness of periphytic ciliate communities using an artificial substratum for marine bioassessment
2012
Zhang, Wei | Xu, Henglong | Jiang, Yong | Zhu, Mingzhuang | Al-Rasheid, Khaled A. S.
Colonization features and taxonomic relatedness measures of ciliate communities have been used as useful indicators for marine bioassessment. The influence of enumeration time periods on analyzing colonization features measures of periphytic ciliate communities was studied in coastal waters of the Yellow Sea, northern China, during the period of May–June 2010. Ciliated protozoan samples were collected at depths of 1 m using an artificial substratum and were analyzed with different enumeration schemes. The ciliate species were identified using living observation and silver impregnation. Data analyses were conducted using a range of multivariate statistical routines. Enumeration time periods represented a strong influence on analyzing both colonization and taxonomic relatedness features of periphytic ciliate communities, although no significant changes occurred in colonization patterns between two enumeration schemes (within 24 and 24–48 h after sampling). The delayed enumeration (within 24–48 h) may result in the species richness, individual abundance, colonization rate decreasing to standard errors of >10 % in samples with almost all colonization ages, and in the similarities of the communities being reduced to 11–38 %. However, the species biodiversity (e.g., species diversity and evenness, except species richness) and taxonomic relatedness (taxonomic diversity, taxonomic distinctness and average taxonomic distinctness, except variation in taxonomic distinctness) measures of periphytic ciliate communities were weakly sensitive to disturbance from the delayed enumeration, achieving standard errors of <10 and <5 % during the colonization periods, respectively. These results suggest that the enumeration should be completed as soon as possible within 24 h after sampling to analyze colonization and taxonomic relatedness features of periphytic ciliate communities, and that the species diversity and taxonomic distinctness measures can be used on a robust bioindicator with weak dependence on enumeration time limits for monitoring programs and ecological investigations in marine ecosystems.
اظهر المزيد [+] اقل [-]A source classification framework supporting pollutant source mapping, pollutant release prediction, transport and load forecasting, and source control planning for urban environments
2012
Lützhøft, Hans-Christian Holten | Donner, Erica | Wickman, Tonie | Eriksson, Eva | Banovec, Primož | Mikkelsen, Peter Steen | Ledin, Anna
PURPOSE: Implementation of current European environmental legislation such as the Water Framework Directive requires access to comprehensive, well-structured pollutant source and release inventories. The aim of this work was to develop a Source Classification Framework (SCF) ideally suited for this purpose. METHODS: Existing source classification systems were examined by a multidisciplinary research team, and an optimised SCF was developed. The performance and usability of the SCF were tested using a selection of 25 chemicals listed as priority pollutants in Europe. RESULTS: The SCF is structured in the form of a relational database and incorporates both qualitative and quantitative source classification and release data. The system supports a wide range of pollution monitoring and management applications. The SCF functioned well in the performance test, which also revealed important gaps in priority pollutant release data. CONCLUSIONS: The SCF provides a well-structured approach for European pollutant source and release classification and management. With further optimisation and demonstration testing, the SCF has the potential to be fully implemented throughout Europe.
اظهر المزيد [+] اقل [-]