排序方式: 共有34条查询结果,搜索用时 15 毫秒
1.
Unger Bianca Herr Helena Viquerat Sacha Gilles Anita Burkhardt-Holm Patricia Siebert Ursula 《Environmental science and pollution research international》2021,28(3):2893-2903
Environmental Science and Pollution Research - Marine debris is known for its ubiquitousness and harmful effects on marine life. This study is the first analysis to provide information on the... 相似文献
2.
This work provides an exploratory analysis on the relative importance of various factors controlling the fate and transport of volatile organic contaminants (in this case, TCE) from a DNAPL source zone located below the water table and into the indoor air. The analysis is conducted using the multi-phase compositional model CompFlow Bio, with the base scenario problem geometry reminiscent of a field experiment conducted by Rivett [Rivett, M.O., (1995), Soil–gas signatures from volatile chlorinated solvents: Borden field experiments. Groundwater, 33(1), 84–98.] at the Borden aquifer where groundwater was observed to transport a contaminant plume a substantial distance without vertical mass transport of the contaminant across the capillary fringe and into the vadose zone. Results for the base scenario model indicate that the structure of the permeability field was largely responsible for deflecting the groundwater plume upward towards the capillary fringe, permitting aqueous phase diffusion to transport the TCE into the vadose zone. Alternative permeability realizations, generated as part of a Monte Carlo simulation process, at times deflected the groundwater plume downwards causing the extended thickness of the saturated zone to insulate the vadose zone from exposure to the TCE by upward diffusive transport. Comparison of attenuation coefficients calculated using the CompFlow Bio and Johnson and Ettinger [Johnson, P.C. and Ettinger, R.A., (1991), Heuristic model for predicting the intrusion rate of contaminant vapors into buildings. Environmental Science and Technology, 25, 1445–1452.] heuristic model exhibited fortuitous agreement for the base scenario problem geometry, with this agreement diverging for the alternative permeability realizations as well as when parameters such as the foundation slab fracture aperture, the indoor air pressure drop, the capillary fringe thickness, and the infiltration rate were varied over typical ranges. 相似文献
3.
4.
5.
6.
Quick fix. Putting out firs. Do it over. Fix it again. Bottlenecks. Come back to it later. Out of stock. Back order. Not what we ordered. Is that the best you can do? It's the contractor's fault. Not within specs. Defective. Nobody's perfect. Lost in the system. Over budget. Delayed. Late penalities. Fines. 相似文献
7.
Karsten Grunewald Christiana Unger Heinz -Jürgen Brauch Wido Schmidt 《Environmental Sciences Europe》2004,16(1):7-14
Objective
Flood sediments were investigated due to the extreme flood situation around Dresden in August 2002Method
The samples have been analyzed by screening inorganic and organic pollutants.Results
It was observed that As, Pb, Cd, Zn, Cu, B and other heavy metals as well as DDT, PCB and Benzo [a] pyren were significantly enriched.Conclusion
Depending on geogenic and anthropogenic impacts, the spatial distribution of these contaminants was different. Organic compounds were dislocated down stream from Czech Republic along the Elbe River. Because of the old ore mining, samples near the Mulde and Wei\eritz Rivers showed high metal pollution.Perspective
More detailed and systematic investigations should be undertaken in the Elbe and Mulde river systems. 相似文献8.
Allopaternal care in the fathead minnow,Pimephales promelas: females prefer males with eggs 总被引:3,自引:0,他引:3
Summary Some species of fishes with exclusive male parental care exhibit the phenomenon of allopaternal care; that is, some males acquire and care for other males' eggs. We conducted a series of experiments to investigate the dynamics and evolution of allopaternal care in one such species, the fathead minnow (Pimephales promelas). In choosing a nest site, a newly reproductive male tended to take over the nest site of a parental male by evicting the resident male, rather than occupy a physically identical empty nest site. The new male generally cared for the old male's eggs, and in most cases, daily egg survival improved under the new male's care. When males were given a choice among unguarded nest sites, they preferred to occupy nest sites already containing eggs. When eggs were randomly assigned to nesting males, females preferred to spawn with males who had eggs in their nest sites. Thus, it appears that female preference for males with eggs led to the evolution of allopaternal care in the fathead minnow. 相似文献
9.
Juliana M. Harding Michael A. Unger Roger Mann E. Alex Jestel Catherine Kilduff 《Marine Biology》2013,160(12):3027-3042
Imposex and decline in reproductive output in marine gastropods have been linked to tributyltin (TBT) exposure. This study describes Chesapeake Bay, USA, veined rapa whelk Rapana venosa imposex incidence and sex ratios from 1998 to 2009. Tissue TBT concentrations (ng g?1) were examined with respect to whelk sex, size, and water temperature at the time of collection, and also to egg case size, hatching success, and veliger diameter. Imposex incidence declined and population sex ratios moved closer to parity from 1998 to 2009. Observed TBT concentrations (ng g?1) were higher in James River than in Ocean View whelks with higher TBT concentrations observed in males than in females. Exponential declines in TBT concentrations from female-specific first to last clutches within a reproductive season were observed, indicating that whelks depurate TBT through egg case deposition. Egg capsule hatching success and veliger size were similar for female and imposex whelks. The R. venosa imposex levels observed in Chesapeake Bay apparently do not affect the production, release, or viability of larvae. 相似文献
10.
During oil and gas production, water is often extracted from geological formations along with the hydrocarbons. These "produced
waters" have been discharged to Nueces Bay since the turn of the century. These effluents were found to be highly toxic, and
sediments in the vicinity of the discharges were also toxic. We developed a map of wells and produced-water discharge sites
in the vicinity of Nueces Bay and identified numerous unplugged wells suitable for conversion to produced water disposal wells.
An economic analysis of conversion to subterranean injection of produced water indicates that most of the wells currently
in production could pay out the cost of conversion to injection in one to three years. The use of one injection well for two
or more water-producing wells could yield greater savings. Wells that could not support the cost of injection are small producers,
and their loss would not constitute a major loss of jobs or dollars to the area. This study could serve as a useful model
for evaluating the economic feasibility of conversion to injection in other areas of Texas and Louisiana. 相似文献