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91.
Multixenobiotic defence mechanism (MXDM) has been recently described as a first line defence system in many aquatic organisms and it has raised attention for its potential as an early biomarker of exposure to environmental stress. In order to investigate the relevance of this biomarker in the freshwater zebra mussel Dreissena polymorpha, we examined its response to exposure and to cessation of exposure. For this purpose, depurated zebra mussels were transplanted to natural rivers or exposed to medium experimentally contaminated with fuel oil 2 in the laboratory. After the exposure period, mussels were submitted to depuration in clean water in the laboratory. The level of MXDM activity was assessed by the efflux method that allows a simple and fast measure of the rate of rhodamine B efflux. MXDM activity was induced following exposure and induction appears earlier after laboratory exposure (3 days) than after in the field exposure (3-14 days). The level of MXDM response could not be directly correlated to exposure dose in the laboratory and to isolated physicochemical parameters or AOX levels in the field. The behaviour of MXDM activity seems to reflect the occurrence of exposure to a global stress rather than to specific compounds. Our results highlighted the possibility to monitor MXDM response in the freshwater zebra mussel. In spite of the difficulty to interpret responses resulting from the lack of specificity of response, multixenobiotic defence mechanism displays qualities to represent a biomarker of general stress in freshwater ecosystems. 相似文献
92.
Elisabet Berggren Marc Debois Janet Duffield Annett Janusch 《Environmental science and pollution research international》1997,4(1):55-59
Council Regulation (EEC) No 2455/92 has been adopted by the Council of the European Communities, in 1992, to improve information exchange on certain dangerous chemicals with third countries, particularly developing countries. To implement the notification procedure in accordance with the Regulation, a database has been developed to manage and simplify the procedure. The software exists in three versions; one adapted for use by the Designated Authorities of the Member States, another for the European Chemicals Bureau (ECB) and the third one is an information version aimed at Designated National Authorities outside the European Union and Industry. The database “EDEXIM” is currently working in a PC environment and is being developed as an on-line system with a stand-alone client/server architecture. 相似文献
93.
Melissa M. Lunden Kenneth L. Revzan Marc L. Fischer Tracy L. Thatcher David Littlejohn Susanne V. Hering Nancy J. Brown 《Atmospheric environment (Oxford, England : 1994)》2003,37(39-40):5633
Recent studies associate particulate air pollution with adverse health effects; however, the exposure to indoor particles of outdoor origin is not well characterized, particularly for individual chemical species. We conducted a field study in an unoccupied, single-story residence in Clovis, California to provide data and analyses to address issues important for assessing exposure. We used real-time particle monitors both outdoors and indoors to quantify nitrate, sulfate, and carbon particulate matter of particle size 2.5 μm or less in diameter (PM-2.5). The results show that measured indoor ammonium nitrate concentrations were significantly lower than would be expected based solely on penetration and deposition losses. The additional reduction can be attributed to the transformation indoors of ammonium nitrate into ammonia and nitric acid gases, which are subsequently lost by deposition and sorption to indoor surfaces. A mass balance model that accounts for the kinetics of ammonium nitrate evaporation was able to reproduce measured indoor ammonium nitrate and nitric acid concentrations, resulting in a fitted value of the deposition velocity for nitric acid of 0.56 cm s−1. The results indicate that indoor exposure to outdoor ammonium nitrate in Central Valley of California are small, and suggest that exposure assessments based on total particle mass measured outdoors may obscure the actual causal relationships for indoor exposure to particles of outdoor origin. 相似文献
94.
Effect of pH on phosphine production and the fate of phosphorus during anaerobic process with granular sludge 总被引:6,自引:0,他引:6
The effect of pH on phosphine formation during anaerobic cultivation of granular sludge was investigated. The sludge was taken from full-scale anaerobic reactors treating brewery wastewater. Acetate and phosphate were used as the carbon source and phosphorus source respectively. After 10 days cultivation in the dark, results showed that acidic conditions were more favorable for free phosphine production. At pH 5, the optimum concentration 86.42 ng PH3 m-3 of free phosphine was obtained. The level at pH 7 was reduced to 18.53 ng PH3 m-3, about 1/5 of the maximum. The maximum concentration of matrix-bound phosphine of 3.30 ng PH3 kg-1 wet sludge was achieved at pH 6. More than 83% of the total phosphine was matrix-bound phosphine, which accounted for 0.003-0.009 per thousand of the phosphate removal, while free phosphine comprised 0.00002-0.001 per thousand of the phosphate removal. Most of the phosphorus removal from solution was turned into chemical precipitation or was adsorbed by sludge. The mechanism of the phosphate reduction-step in the formation of phosphine production is still unknown. The promotion of phosphine formation by low pH is compatible with an acidic bio-corrosion mechanism of metal particles in the sludge or of metal phosphides which form phosphine at low pH. 相似文献
95.
Aline Chiabai Joseph V. Spadaro Marc B. Neumann 《Mitigation and Adaptation Strategies for Global Change》2018,23(7):1159-1176
The study aims to explore the main drivers influencing the economic appraisal of heat warning systems by integrating epidemiological modelling and benefit-cost analysis. To shed insights on heat wave mortality valuation, we consider three valuation schemes: (i) a traditional one, where the value of a statistical life (VSL) is applied to both displaced and premature mortality; (ii) an intermediate one, with VSL applied for premature mortality and value of a life year (VOLY) for displaced mortality; and (iii) a conservative one, where both premature and displaced mortality are quantified in terms of loss of life expectancy, and then valued using the VOLY approach. When applying these three schemes to Madrid (Spain), we obtain a benefit-cost ratio varying from 12 to 3700. We find that the choice of the valuation scheme has the largest influence, whereas other parameters such as attributable risk, displaced mortality ratio, or the comprehensiveness and effectiveness of the heat warning system are less influential. The results raise the question of which is the most appropriate approach to value mortality in the context of heat waves, given that the lower bound estimate for the benefit-cost ratio (option iii using VOLY) is up to two orders of magnitude lower than the value based on the traditional VSL approach (option i). The choice of the valuation methodology has significant implications for public health authorities at the local and regional scale, which becomes highly relevant for locations where the application of the VOLY approach could lead to benefit-cost ratios significantly lower than 1. We propose that specific metrics for premature and displaced VOLYs should be developed for the context of heat waves. Until such values are available, we suggest testing the economic viability of heat warning systems under the three proposed valuation schemes (i–iii) and using values for VOLY commonly applied in air pollution as the health end points are similar. Lastly, periodical reassessment of heat alert plans should be performed by public health authorities to monitor their long-term viability and cost-effectiveness. 相似文献
96.
Jean-Franois Cabaraux Franois-Xavier Philippe Martine Laitat Bernard Canart Marc Vandenheede Baudouin Nicks 《Agriculture, ecosystems & environment》2009,130(3-4):86-92
Gaseous emissions from agriculture contribute to a number of environmental effects. Carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) are greenhouse gases taking part to the global problem of climate change. Ammonia (NH3) emissions are responsible of soil acidification and eutrophication and contribute also to indirect emissions of N2O. This work evaluated the influence of the type of floor on the emissions of these gases in the raising of weaned pigs. Two trials were carried out. In the first trial, the animals were kept either on fully slatted floor or on straw-based deep litter and, in the second one, either on fully slatted floor or on sawdust-based deep litter. For each trial and on each type of floor, 2 successive batches of weaned pigs were raised without changing the litter or emptying the slurry pit between the 2 batches. The rooms were automatically ventilated to maintain a constant ambient temperature.The performance of the animals was not significantly different according to the floor type. In trial 1, the nitrogen contents of the straw deep litter (including the substrate) and slurry were respectively 276 and 389 g pig−1. In trial 2, the sawdust deep litter and slurry nitrogen contents were respectively 122 and 318 g pig−1.Raising pigs on straw deep litter produced proportionately around 100% more NH3 than raising pigs on slatted floor (0.61 g NH3-N d−1 pig−1 vs. 0.31 g NH3-N d−1 pig−1; P < 0.05). Differences in CO2, H2O and CH4 emissions were not significant between systems. Raising pigs on sawdust deep litter produced also proportionately more NH3 (+52%; 0.55 g NH3-N d−1 pig−1 vs. 0.36 g NH3-N d−1 pig−1; P < 0.01) but also more CO2 (+25%; 427 g d−1 pig−1 vs. 341 g d−1 pig−1; P < 0.001) and H2O (+65%; 981 g d−1 pig−1 vs. 593 g d−1 pig−1; P < 0.001) and less CH4 (−40%; 0.52 g d−1 pig−1 vs. 0.86 g d−1 pig−1; P < 0.001) than raising pigs on slatted floor. Practically no N2O emission was observed from rooms with slatted floor while the N2O emissions were 0.03 and 0.32 g N2O-N d−1 pig−1 for the straw and sawdust deep litter respectively. The warming potential of the greenhouse gases (N2O + CH4), were about 22, 34 and 168 g CO2 equivalents per day and per pig on fully slatted floor, straw or sawdust deep litter respectively.In conclusion, pollutant gas emissions from rearing of weaned pig seem lower with fully slatted plastic floor system than with deep litter systems. 相似文献
97.
Marc Russell John Rogers Stephen Jordan Darrin Dantin James Harvey Janet Nestlerode Federico Alvarez 《Journal of Coastal Conservation》2011,15(4):647-658
The Tampa Bay Ecosystem Services Demonstration Project (TBESDP) is part of the U.S. Environmental Protection Agency’s Ecosystem
Services Research Program. The principal objectives of TBESDP are to (1) quantify the ecosystem services of the Tampa Bay
watershed, (2) determine the value of ecosystem services to society, (3) predict the supply of ecosystem services under future
scenarios of population growth and climate change, and (4) apply this knowledge through models and tools that will support
the best informed environmental decisions possible. The scope and complexity of this project required intensive effort to
establish which services can be quantified by applying existing models, data, and scientific literature and which services
will require supporting research. Research priorities were assessed by: (1) developing and refining conceptual models of major
ecosystems in the Tampa Bay region, (2) gathering input from stakeholders about the relative importance and values of various
ecosystem services, (3) preparing and reviewing a bibliometric analysis of the volume of scientific literature relevant to
the ecosystems and services of interest, and (4) evaluating an integrated analysis of importance, value, and availability
of scientific information. This analysis led us to focus on two research priorities, seagrass-habitat functions as support
for fishery production, and wetlands as regulators of water quality. 相似文献
98.
99.
Samson G. Mengistu Heather E. Golden Charles R. Lane Jay R. Christensen Michael L. Wine Ellen D’Amico Amy Prues Scott G. Leibowitz Jana E. Compton Marc H. Weber Ryan A. Hill 《Journal of the American Water Resources Association》2023,59(5):1162-1179
Eutrophication, harmful algal blooms, and human health impacts are critical environmental challenges resulting from excess nitrogen and phosphorus in surface waters. Yet we have limited information regarding how wetland characteristics mediate water quality across watershed scales. We developed a large, novel set of spatial variables characterizing hydrological flowpaths from wetlands to streams, that is, “wetland hydrological transport variables,” to explore how wetlands statistically explain the variability in total nitrogen (TN) and total phosphorus (TP) concentrations across the Upper Mississippi River Basin (UMRB) in the United States. We found that wetland flowpath variables improved landscape-to-aquatic nutrient multilinear regression models (from R2 = 0.89 to 0.91 for TN; R2 = 0.53 to 0.84 for TP) and provided insights into potential processes governing how wetlands influence watershed-scale TN and TP concentrations. Specifically, flowpath variables describing flow-attenuating environments, for example, subsurface transport compared to overland flowpaths, were related to lower TN and TP concentrations. Frequent hydrological connections from wetlands to streams were also linked to low TP concentrations, which likely suggests a nutrient source limitation in some areas of the UMRB. Consideration of wetland flowpaths could inform management and conservation activities designed to reduce nutrient export to downstream waters. 相似文献
100.
Miguel C. Leal Stella A. Berger Christine Ferrier-Pagès Ricardo Calado Jay Brandes Marc E. Frischer Jens C. Nejstgaard 《Marine Biology》2014,161(9):2191-2197
Gorgonians are widespread sub-littoral benthic suspension feeders in the world oceans. However, data on their trophic ecology and role in benthic–pelagic coupling and biogeochemical cycles remain limited. This study assesses the trophic ecology of Leptogorgia virgulata in the Skidaway River estuary, USA (31.9896N, 81.0242W) by analysing carbon and nitrogen isotopic signatures of its soft tissue and different-sized fractions of particulate organic matter (POM) in its environment. Samples were taken in 5 April, 2 August, and 15 October 2012 and 11 January 2013. Results support a distinct temporal shift in the diet of L. virgulata from the POM fraction <10 µm (i.e. pico- and nanoplankton) to the 10–63-µm fraction (i.e. microplankton). This trophic regime is likely associated with the natural abundance of prey items within these size classes, thus suggesting that L. virgulata may be an opportunistic feeder, and seasonal shifts in food availability in the water column affect its diet. As such small prey items affect the bioenergetics of L. virgulata, it is important to understand the implications of changes in food availability associated with environmental drivers on the physiology and population dynamics of this dominant species in the western Atlantic Ocean. 相似文献