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201.
Eichhornia crassipes was tested for its ability to bioconcentrate 8 toxic metals (Ag, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) commonly found in wastewater
from industries. Young plants of equal size were grown hydroponically and amended with 0, 0.1, 0.3, 0.5, 1.0, 3.0, and 5.0
mM of each heavy metal individually for 21 days. The test plant had the lowest and the highest tolerance indices for Hg and
Zn, respectively. A significant (P ≤ .05) reduction in biomass production was observed in metal treated plants compared with the control. All strace elements
accumulated to higher concentrations in roots than in shoots. Trace element concentrations in tissues and the bioconcentration
factors (BCF) were proportional to the initial concentration of individual metal in the growth medium and the duration of
exposure. From a phytoremediation perspective, E. crassipes is a promising plant species for remediation of natural water bodies and/or wastewater polluted with low levels of Zn, Cr,
Cu, Cd, Pb, Ag and Ni. 相似文献
202.
Ecological risk assessment (ERA) evaluates potential causal relationships between multiple sources and stressors and impacts on valued ecosystem components. ERAs applied at the watershed scale have many similarities to the place-based analyses that are undertaken to develop Total Maximum Daily Loads (TMDLs), in which linkages are established between stressors, sources, and water quality standards, including support of designated uses. TMDLs focus on achieving water quality standards associated with attainment of designated uses. In attempting to attain the water quality standard, many TMDLs focus on the stressor of concern rather than the ecological endpoint or indicators of the designated use that the standard is meant to protect. A watershed ecological risk assessment (WERA), at least in theory, examines effects of most likely stressors, as well as their probable sources in the watershed, to prioritize management options that will most likely result in meeting environmental goals or uses. Useful WERA principles that can be applied to TMDL development include: development and use of comprehensive conceptual models in the Problem Identification step of TMDLs; use of a transparent process for selecting Numeric Targets for TMDLs based on assessment endpoints derived from the management goal or designated use under consideration; analysis of co-occurring stressors likely to cause beneficial use impairment based on the conceptual model; use of explicit uncertainty analyses in the Linkage Analysis step of TMDL development; and frequent stakeholder interactions throughout the process. WERA principles are currently most applicable to those TMDLs in which there is no numeric standard and, therefore, indicators and targets need to be developed, such as many nutrient or sediment TMDLs. WERA methods can also be useful in determining TMDL targets in situations where simply targeting the water quality standard may re-attain the numeric criterion but not the broader designated use. Better incorporation of problem formulation principles from WERA into the TMDL development process would be helpful in improving the scientific rigor of TMDLs. 相似文献
203.
Mark M. Wilsnack Victor P. Kelson Jack F. Wittman 《Journal of the American Water Resources Association》2005,41(1):67-76
ABSTRACT: The large volumes of ground water that are discharged from the Everglades toward the Miami metropolitan area have historically posed a significant environmental water supply problem. In order to analyze the effects of seepage barriers on these subsurface outflows, the analytic element modeling code GFLOW was used to construct a ground water flow model of a region that includes a portion of the Everglades along with adjacent developed areas. The hydrology of this region can be characterized by a highly transmissive surficial aquifer in hydraulic contact with wetlands and canals. Calibration of the model to both wet and dry season conditions yielded satisfactory results, and it was concluded that the analytic element method is a suitable technique for modeling ground water flow in the Everglades environment. Finally, the model was used to evaluate the potential effectiveness of a subsurface barrier approximately two miles long for increasing water levels within the adjacent fringes of the Everglades National Park. It was found that the barrier had a negligible effect on water levels due to both its relatively short length and the high transmissivity of the surficial aquifer. 相似文献
204.
Effects of spent engine oil on the growth parameters, chlorophyll and protein levels of Amaranthus hybridus L. 总被引:2,自引:0,他引:2
The susceptibility of Amaranthus hybridus L. seedlings to spent engine oil was investigated in soil supplemented with concentrations of oil ranging from 1–5 percent v/w. Parameters considered were relative growth rate (RGR), leaf area ratio (LAR), whole plant height, leaf area, leaf number, chlorophyll and protein levels. A relationship was found to exist between the inhibitory effects and the treatment concentrations. After seventy days growth in the treated soils, the mean height and leaf area of plants in soils treated with 5 percent spent engine oil were 27.0±1.25 cm and 5.63±0.36 cm2. These were significantly different (at p=0.05) from the respective values of 41.4±0.8 cm and 13.44±0.22 cm2 for the control plants. Levels of total chlorophyll (per gram fresh weight of leaves) and protein (per gram dry weight of whole plant) were higher in the control plants compared with those grown in oil treated soil. Results obtained from the growth analysis showed the inhibitory effects of spent engine oil on Amaranthus hybridus L. 相似文献
205.
Gyamfi Bright Akwasi Bekun Festus Victor Balsalobre-Lorente Daniel ONIFADE Stephen Taiwo Ampomah Asiedu Benjamin 《Environment, Development and Sustainability》2022,24(10):11852-11870
Environment, Development and Sustainability - This study is motivated by the United Nations Sustainable Development Goals (UN-SDG-7,8,11,12 and 13) on the need for clean and responsible energy... 相似文献
206.
Grainger ALAN Stafford Smith MARK Squires Victor R. Glenn Edward P. 《Mitigation and Adaptation Strategies for Global Change》2000,5(4):361-377
Poor knowledge of links between desertification and globalclimate change is limiting funding from the Global Environment Facility foranti-desertification projects and realization of synergies between theConvention to Combat Desertification (CCD) and the FrameworkConvention on Climate Change (FCCC). Greater convergence betweenresearch in the two fields could overcome these limitations, improve ourknowledge of desertification, and benefit four areas of global climate changestudies: mitigation assessment; accounting for land cover change in thecarbon budget; land surface-atmosphere interactions; and climate changeimpact forecasting. Convergence would be assisted if desertification weretreated more as a special case in dry areas of the global process of landdegradation, and stimulated by: (a) closer cooperation between the FCCCand CCD; (b) better informal networking between desertification and globalclimate change scientists, e.g. within the framework of theIntergovernmental Panel on Climate Change (IPCC). Both strategies wouldbe facilitated if the FCCC and CCD requested the IPCC to provide ascientific framework for realizing the synergies between them. 相似文献
207.
Salvatore Collura Bruno Azambre Gisèle Finqueneisel Thierry Zimny Jean Victor Weber 《Environmental Chemistry Letters》2006,4(2):75-78
In this paper we present, for the first time, data on the combustion of Miscanthus × Giganteus straw and pellets. We found that the heating value of Miscanthus is 17.744 MJ/kg. The gaseous emission indices of SO2, NO
x
and total organic carbon (TOC) in the exhaust are reported and compared with the European standards for biomass boilers. On the basis of our results, it is possible to evaluate a net energy yield between 152 and 326 MJ/hectare/year for the cultivation of Miscanthus with an energy balance estimated to be in the range of 7.7–15.4. According to the presented results, it seems reasonable to consider Miscanthus as a promising candidate as alternative fuel. 相似文献
208.
Modifying Forest Management for Biodiversity 总被引:1,自引:0,他引:1
Victor J. Rudolph 《Conservation biology》2003,17(5):1463-1464
209.
The removal and recovery of heavy metals from a coal pilerunoff water using a mixture of multiple metal-tolerantbacterial strains of ATCC 55673, and ATCC 55674 and a Pseudomonas sp. was investigated. The analysis of elementalcomposition of metal precipitates recovered from the bacterialbiomass by transmission electron microscopy and energy dispersiveX-ray analysis revealed the presence of metals originally presentin the wastewater. In addition, analysis of metals in culturesupernatant and bacterial biomass by inductively coupled plasmaemission spectroscopy (ICP-ES) indicated a removal range of 82-100% and a recovery of 15-58% of metals from the wastewater and bacterial biomass, respectively. 相似文献
210.
A method is presented for calculating allowable use of tracked vehicles on the US Army's Pinon Canyon Maneuver Site in southeastern Colorado. The first step in this process is to determine the sheet and rill erosion rate on each soil series using the revised Universal Soil Loss Equation. Soil series are then ranked according to their trainability (e g., ranked based on how much vegetative cover can be lost without exceeding soil loss tolerance) Maximum onetime surface use, allowable surface use per year, usable hectares per year, and tracked vehicle days per year can then be calculated Examples are given to illustrate how these values can be manipulated to assist land managers and military trainers to better plan and match training missions to available land. Also, short- and long-term monitoring schemes are presented that can be used to verify or adjust estimates of allowable use. The methods presented can be converted to determine allowable use of other types of activities that disturb the vegetation and expose the soil surface to the erosive forces of wind and water (e g, recreational and off-road vehicles). 相似文献