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641.
This paper presents results of investigations on the influence of humic substances (humate, HS) on the biological treatment of wastewater containing heavy metals (Cr, Cu, Fe, Mn, Ni, and Zn). Respirometric studies indicated that the investigated system complied with the Haldane model for inhibitory wastes. Chemical analyses showed that, while the soluble COD removal was high (82%), only 7% of ammonia was oxidized to nitrate. An addition of HS (500 mg L−1) mitigated the inhibitory effect of the wastewater on the returned activated sludge. The system with HS complied with the Monod model for non-inhibitory wastes, and the removal of ammonia and metals was 99% and over 90%, respectively. It is suggested that an application of HS could be beneficial for treatment plants receiving wastewater streams containing heavy metals. 相似文献
642.
Interacting effects of sulphate pollution, sulphide toxicity and eutrophication on vegetation development in fens: A mesocosm experiment 总被引:1,自引:0,他引:1
Jeroen J.M. Geurts Judith M. Sarneel Jan G.M. Roelofs Leon P.M. Lamers 《Environmental pollution (Barking, Essex : 1987)》2009,157(7):2072-2081
Both eutrophication and SO4 pollution can lead to higher availability of nutrients and potentially toxic compounds in wetlands. To unravel the interaction between the level of eutrophication and toxicity at species and community level, effects of SO4 were tested in nutrient-poor and nutrient-rich fen mesocosms. Biomass production of aquatic and semi-aquatic macrophytes and colonization of the water layer increased after fertilization, leading to dominance of highly competitive species. SO4 addition increased alkalinity and sulphide concentrations, leading to decomposition and additional eutrophication. SO4 pollution and concomitant sulphide production considerably reduced biomass production and colonization, but macrophytes were less vulnerable in fertilized conditions. The experiment shows that competition between species, vegetation succession and terrestrialization are not only influenced by nutrient availability, but also by toxicity, which strongly interacts with the level of eutrophication. This implies that previously neutralized toxicity effects in eutrophied fens may appear after nutrient reduction measures have been taken. 相似文献
643.
Henner Hollert Sebastian Hudjetz Evelyn Claus Werner Manz Georg Reifferscheid Peter Heininger Jan Schwarzbauer Wolfgang Ahlf Thomas Braunbeck Werner Brack Tobias Schulze Andreas Sch?ffer und Hans-Toni Ratte 《Umweltwissenschaften und Schadstoff-Forschung》2009,21(3):235-237
Ohne Zusammenfassung
Verantwortliche Herausgeber: Jan Schwarzbauer · Peter Heininger · Evelyn Claus
相似文献
Henner Hollert (Corresponding author)Email: |
Evelyn ClausEmail: |
Peter HeiningerEmail: |
Jan SchwarzbauerEmail: |
644.
Conservation subdivision design has been promoted as a way to protect ecologically sensitive areas while maintaining housing densities comparable to standard subdivisions, but many developers and planners question the appeal of conservation design to consumers. This study was conducted to compare economic aspects of conservation subdivision design to standard subdivision design in the midwestern United States. Three methods were used to determine the value homebuyers have for embedded conservation features in residential areas: transactional analyses (to indicate the value homebuyers have expressed for such features in the past); hedonic analyses (to determine the proportion of present value of homes attributable to such features); and contingent valuation (to examine willingness to pay according to homebuyers' preferred features, an indicator of potential future investment). Transactional analyses were based on assessment and transaction data for homes in three conservation-oriented subdivisions and three standard subdivisions in Cedar Rapids, Iowa, United States. Hedonic price models were also derived from assessment and transaction data. Contingent valuation analyses were based on a survey of residents in the same six subdivisions. Transactional data indicated higher 5-year appreciation rates for conservation versus standard subdivision design. Hedonic price models revealed that well-integrated conservation features (e.g. protected stream corridors) within subdivisions have a positive effect on home prices. Sixty-six percent of all respondents indicated willingness to pay for more embedded open space. Maximum willingness to pay was related to several factors including income, gender, desired level of open space, and concern about urban development. Overall, these results indicate that consumer demand and willingness to pay for conservation subdivision design are positive and should not be considered a barrier to implementation. 相似文献
645.
Strategic assessment of the magnitude and impacts of sand mining in Poyang Lake, China 总被引:2,自引:0,他引:2
Jan de Leeuw David Shankman Guofeng Wu Willem Frederik de Boer James Burnham Qing He Herve Yesou Jing Xiao 《Regional Environmental Change》2010,10(2):95-102
Planning for the extraction of aggregates is typically dealt with at a case to case basis, without assessing environmental
impacts strategically. In this study we assess the impact of sand mining in Poyang Lake, where dredging began in 2001 after
sand mining in the Yangtze River had been banned. In April 2008 concern over the impact on the biodiversity led to a ban on
sand mining in Poyang Lake until further plans could be developed. Planning will require consideration of both sand extraction
in relation to available sediment resources and also environmental impacts within the context of future demand for sand in
the lower Yangtze Valley. We used pairs of near-infrared (NIR) Aster satellite imagery to estimate the number of vessels leaving
the lake. Based on this we calculated a rate of sand extraction of 236 million m3 year−1 in 2005–2006. This corresponds to 9% of the total Chinese demand for sand. It qualifies Poyang Lake as probably the largest
sand mining operation in the world. It also indicates that sand extraction currently dominates the sediment balance of the
lower Yangtze River. A positive relation between demand for sand and GDP, revealed by historic data from the USA, suggests
that the current per capita demand for sand in China might increase in the near future from 2 to 4 m3 year−1. We review various environmental impacts and question whether it will be possible to preserve the rich biodiversity of the
lake, while continuing at the same time satisfying the increasing Chinese demand for sand. Finally we review alternative options
for sand mining, in order to relieve the pressure from the Poyang Lake ecosystem. 相似文献
646.
Biqing Zhu Johannes Kros Jan Peter Lesschen Igor Georgy Staritsky Wim de Vries 《Regional Environmental Change》2016,16(6):1571-1582
The global animal food chain has a large contribution to the global anthropogenic greenhouse gas (GHG) emissions, but its share and sources vary highly across the world. However, the assessment of GHG emissions from livestock production is subject to various uncertainties, which have not yet been well quantified at large spatial scale. We assessed the uncertainties in the relations between animal production (milk, meat, egg) and the CO2, CH4, and N2O emissions in Africa, Latin America and the European Union, using the MITERRA-Global model. The uncertainties in model inputs were derived from time series of statistical data, literature review or expert knowledge. These model inputs and parameters were further divided into nine groups based on type of data and affected greenhouse gas. The final model output uncertainty and the uncertainty contribution of each group of model inputs to the uncertainty were quantified using a Monte Carlo approach, taking into account their spatial and cross-correlation. GHG emissions and their uncertainties were determined per livestock sector, per product and per emission source category. Results show large variation in the GHG emissions and their uncertainties for different continents, livestock sectors products or source categories. The uncertainty of total GHG emissions from livestock sectors is higher in Africa and Latin America than in the European Union. The uncertainty of CH4 emission is lower than that for N2O and CO2. Livestock parameters, CH4 emission factors and N emission factors contribute most to the uncertainty in the total model output. The reliability of GHG emissions from livestock sectors is relatively high (low uncertainty) at continental level, but could be lower at country level. 相似文献
647.
Jan?StenisEmail author William?Hogland 《Environment, Development and Sustainability》2016,18(1):95-109
A cost structure is proposed for optimizing the recirculation and recycling of commodities and energy usage considering regional, national and global operating scales. The methodology proposed involves business administration theory and economics and employs the previously introduced equality principle and the model for efficient use of resources for optimal production economy (EUROPE) to impose shadow costs on unwanted material wastes and energy residuals that produce economic incentives to reduce such wastes at the source. A case study presents the practical application of the proposed theory in a national and a global context. It is concluded that the presented methodology is useful for increasing the cost-effectiveness and optimizing recirculation and recycling in the usage of energy resources and natural resources in general. Profitability increases, technology is advanced and environmental conditions improve simultaneously through the application of the EUROPE model to analyze government policy related to the recirculation and recycling of solid wastes and energy. Furthermore, the equity of the distribution of such recirculation and recycling facilities is improved. The developed methods are useful information support tools for decision-making in the management of energy and other natural resources with emphasis on the economics of recirculated and recycled residuals. 相似文献
648.
Jadwiga Wyszkowska Edyta Boros-Lajszner Agata Borowik Małgorzata Baćmaga Jan Kucharski Monika Tomkiel 《Journal of environmental science and health. Part. B》2016,51(5):261-270
This study was undertaken to evaluate zinc's influence on the resistance of organotrophic bacteria, actinomyces, fungi, dehydrogenases, catalase and urease. The experiment was conducted in a greenhouse of the University of Warmia and Mazury (UWM) in Olsztyn, Poland. Plastic pots were filled with 3 kg of sandy loam with pHKCl – 7.0 each. The experimental variables were: zinc applied to soil at six doses: 100, 300, 600, 1,200, 2,400 and 4,800 mg of Zn2+ kg?1 in the form of ZnCl2 (zinc chloride), and species of plant: oat (Avena sativa L.) cv. Chwat and white mustard (Sinapis alba) cv. Rota. Soil without the addition of zinc served as the control. During the growing season, soil samples were subjected to microbiological analyses on experimental days 25 and 50 to determine the abundance of organotrophic bacteria, actinomyces and fungi, and the activity of dehydrogenases, catalase and urease, which provided a basis for determining the soil resistance index (RS). The physicochemical properties of soil were determined after harvest. The results of this study indicate that excessive concentrations of zinc have an adverse impact on microbial growth and the activity of soil enzymes. The resistance of organotrophic bacteria, actinomyces, fungi, dehydrogenases, catalase and urease decreased with an increase in the degree of soil contamination with zinc. Dehydrogenases were most sensitive and urease was least sensitive to soil contamination with zinc. Zinc also exerted an adverse influence on the physicochemical properties of soil and plant development. The growth of oat and white mustard plants was almost completely inhibited in response to the highest zinc doses of 2,400 and 4,800 mg Zn2+ kg?1. 相似文献
649.
Ingrid Öborn Jan Bengtsson Fredrik Hedenus Lotta Rydhmer Maria Stenström Katarina Vrede Charles Westin Ulf Magnusson 《Ambio》2013,42(7):823-839
To increase the awareness of society to the challenges of global food security, we developed five contrasting global and European scenarios for 2050 and used these to identify important issues for future agricultural research. Using a scenario development method known as morphological analysis, scenarios were constructed that took economic, political, technical, and environmental factors into account. With the scenarios as a starting point future challenges were discussed and research issues and questions were identified in an interactive process with stakeholders and researchers. Based on the outcome of this process, six socioeconomic and biophysical overarching challenges for future agricultural were formulated and related research issues identified. The outcome was compared with research priorities generated in five other research programs. In comparison, our research questions focus more on societal values and the role of consumers in influencing agricultural production, as well as on policy formulation and resolving conflicting goals, areas that are presently under-represented in agricultural research. The partly new and more interdisciplinary research priorities identified in Future Agriculture compared to other programs analyzed are likely a result of the methodological approach used, combining scenarios and interaction between stakeholders and researchers. 相似文献
650.
Understanding adsorption processes of butyltins (BTs) such as monobutyltin (MBT) and dibutyltin (DBT) by black carbons is important for the evaluation of BT exposure risks to organisms and humans. However, relevant knowledge is scarce. In this study, the acidity constants pKa,1 = 2.3, pKa,2 = 3.5 and pKa,3 = 5.9 for MBT and pKa,1 = 3.0 and pKa,2 = 5.1 for DBT are estimated via potentiometric titration. Additionally, adsorption isotherms of BTs to a wheat charcoal were determined. The adsorption behavior was observed to be pH-dependent due to BT speciation and the pH-dependent surface charge of the charcoal. MBT adsorption to the charcoal decreases with increasing pH from 4 to 8, while the highest adsorption occurs at pH 6 for DBT. Adsorption of the BTs is successfully described in the pH range of 3-10 by using a newly developed pH-dependent Dual Langmuir model. The model has the potential to predict the interaction of BT species with charcoal, which can contribute to the risk assessments of BTs in the environment. 相似文献