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531.
Youssef Filali-Meknassi Muriel Auriol Craig D Adams Rao Y Surampalli 《Water environment research》2007,79(6):687-696
In this study, the occurrence of trace amounts of natural and synthetic steroid estrogens in the aquatic environment was studied using liquid chromatography coupled with electrospray mass spectrometry, following solid-phase extraction (SPE). The SPE was performed with C18 and NH2 cartridges. The first objective was to develop a reliable method for analyzing steroid estrogens (resulting from human and animal excretions) in different matrices. The method developed was then applied to quantify the occurrence of natural and synthetic hormones (estrone [E1], 17beta-estradiol [betaE2], 17alpha-estradiol [alphaE2], estriol [E3], and 17alpha-ethinylestradiol [EE2]) in environmental samples in surface water and wastewater treatment plant (WWTP) influent and effluent. In the WWTP influents, betaE2, alphaE2, and E3 were identified as ranging up to 72.6 ng/L in WWTP influent and to 16 ng/L in WWTP effluent. Analysis o f surface wa ter sampled upstream from the WWTP revealed the presence of all five estrogens, at levels up to 19.8 ng/L. These concentrations of estrogens pose an issue for large and small communities, because they are higher than the recommended guidelines for estrogen-active compounds and because a lot of communities use surface water as drinking-water sources. 相似文献
532.
Summer phytoplankton assemblages from surface waters off Kuwait were enriched with levels of eolian dust (105, 106, and 107 mg/m3), similar to seasonal dust fallout for this region. Algal growth was positive and dose dependent. Highest biomass was up
to 527 μg chlorophyll a/l on day 5. The maximum doublings of biomass per day were 0.64, 0.77, and 1.42, corresponding to 105, 106, and 107 mg/m3 enrichment and were significantly higher than the 0.56 for control. Changes in the phytoplankton species composition occurred
with changes in biomass, with small algae dominating peak populations. It is suggested that through enrichment of trace elements
via eolian dust, a high level of phytoplankton biomass and growth can be sustained in this arid environment.
Received: 15 October / Accepted in revised form: 16 June 1999 相似文献
533.
534.
N Reid P K Misra R Bloxam D Yap S T Rao K Civerolo E Brankov R J Vet 《Journal of the Air & Waste Management Association (1995)》2001,51(11):1561-1567
Anomalies appear to exist in our understanding of atmospheric sulfur compounds, specifically as evidenced in the time trends of the different chemical forms of these compounds. Trends determined at a number of locations by several different groups seem to indicate that, responding to emission reductions across North America, the concentration of SO2 in the atmosphere is declining more rapidly than that of aerosol SO4(2-). A number of possible reasons for this discrepancy are examined, but it is not possible to provide a definitive answer at this stage. The intent is to stimulate debate, because shortcomings in our understanding of the processes involved could have profound implications for the credibility of abatement strategies and policies for both acid deposition and fine particulate matter (PM). 相似文献
535.
Robert E. Eskridge William B. Petersen S. Trivikrama Rao 《Journal of the Air & Waste Management Association (1995)》2013,63(3):312-317
Recent theoretical and experimental investigations Indicate that turbulent diffusion behind moving vehicles Is Influenced by the speed of the vehicle. Vertical wake induced turbulent diffusion, explicitly treated in the numerical ROADWAY model, is proportional to the square of the wind speed relative to the moving vehicle. Hence, the model predictions of turbulent mixing and pollutant concentrations on and downwind of a roadway are dependent upon the traffic speed. It Is expected from theoretical considerations that the effect of vehicle speed on pollutant concentrations will be more significant during stable atmospheric conditions, because in neutral and unstable conditions the vehicle-wake turbulence is quickly masked by the ambient turbulence. In this study, experimental data are utilized to evaluate the theoretical predictions of the effects of traffic speed on the ambient pollutant concentrations. The effects of vehicle speed upon ambient concentrations are investigated through wind tunnel experiments and field studies that used dual tracers. Consistent with predictions of the ROADWAY model, data obtained near the Long Island Expressway indicate that the influence of traffic speed on the ambient pollutant concentrations Is not significant during unstable and neutral conditions. The Long Island experiment did not provide sufficient field data to assess the model predictions of the traffic speed effect during stable atmospheric conditions. 相似文献
536.
Rajendra Kumar Isaac Dinesh Kumar Syed Mohd Azmi 《Environmental monitoring and assessment》2011,172(1-4):517-527
This study was aimed to establish background and reference values of total heavy metals in soils from a representative area of Albania (Tirana). Thirty-eight soil samples collected from genetic horizons of major soil types of Tirana were analyzed for important physicochemical properties by standard methods and for total contents of Cd, Cr, Ni, Pb, Zn, and Cu by atomic absorption spectrometer, after extraction with aqua regia. The results showed that the total contents of Cd, Cr, Ni, Pb, Zn, and Cu in surface horizons varied widely with respective mean values of 0.3 (??0.6), 174.2 (??63.7), 305.9 (??133.0), 19.7 (??12.4), 95.5 (??26.3), and 42.7 (??6.8) mg/kg. The highest metal contents were found in two soils developed in limestone. The depth distribution of metals showed a tendency for accumulation of Cd and Pb in the surface horizons of three soils, suggesting that these metals partially come from anthropogenic inputs. Correlation analysis indicated that the metal contents of soils were controlled by soil properties, including pH, CaCO3, clay, organic matter, cation exchange capacity, and Fe oxides. The background values (given as the 90th percentile) were much higher than those reported in the literature, showing that the levels of respective metals were naturally higher. The total metal contents of some soils were above background levels, suggesting metal pollution. The reference values for all the analyzed metals were quite consistent with those of the Dutch system. The proposed background and reference values can be used to evaluate the soil pollution with these elements. 相似文献
537.
Rucha Vaidya Kisan Kodam Vikram Ghole K. Surya Mohan Rao 《Journal of environmental management》2010,91(9):1821-1830
The aim of the present study was to devise and validate an appropriate treatment process for disposal of hazardous barium and cyanide waste into a landfill at a Common Hazardous Waste Treatment Storage Disposal Facility (CHWTSDF). The waste was generated during the process of hardening of steel components and contains cyanide (reactive) and barium (toxic) as major contaminants. In the present study chemical fixation of the contaminants was carried out. The cyanide was treated by alkali chlorination with calcium hypochlorite and barium by precipitation with sodium sulfate as barium sulfate. The pretreated mixture was then solidified and stabilized by binding with a combination of slag cement, ordinary Portland cement and fly ash, molded into blocks (5 × 5 × 5 cm) and cured for a period of 3, 7 and 28 days. The final experiments were conducted with 18 recipe mixtures of waste + additive:binder (W:B) ratios. The W:B ratios were taken as 80:20, 70:30 and 50:50. The optimum proportions of additives and binders were finalized on the basis of the criteria of unconfined compressive strength and leachability. The leachability studies were conducted using the Toxicity Characteristic Leaching Procedure. The blocks were analyzed for various physical and leachable chemical parameters at the end of each curing period. Based on the results of the analysis, two recipe mixtures, with compositions – 50% of [waste + (120 g Ca(OCl)2 + 290 g Na2SO4) kg?1 of waste] + 50% of binders, were validated for in situ stabilization into a secured landfill of CHWTSDF. 相似文献
538.
C. K. Sreedharan Jagannadha Rao Matta 《Environment, Development and Sustainability》2010,12(6):877-888
In a major deviation from conventional joint forest management approaches where the emphasis of management is on provision
of forest products to the participating villagers, the Tamil Nadu Afforestation Project (TAP) focused on poverty alleviation
as the principal means to achieve sustainable forest management. This study assesses the effectiveness of TAP’s strategy in
improving the ecology and socio-economic conditions of forest fringe villages using a diverse set of research methods. Results
indicate that in a span of four to seven years, there was significant increase in forest cover, biodiversity, and agricultural
productivity. The project villages have also shown considerable progress in various indicators of socio-economic development.
The authors, however, suggest continued poverty alleviation and promotion of alternative livelihood opportunities to place
the programme on a stable ground. Meeting the development needs of local villagers through strong and durable institutional
linkages is also suggested for the programme to sustain and succeed. 相似文献
539.
Isotopic evidences for provenance of East Asian Dust 总被引:1,自引:0,他引:1
Jiedong Yang Gaojun Li Wenbo Rao Junfeng Ji 《Atmospheric environment (Oxford, England : 1994)》2009,43(29):4481-4490
We have systematically collected samples in the possible source regions (the deserts and sandy lands of North China, northeastern past of the Tibetan Plateau, Chinese Loess Plateau and southern part of Mongolia) of the East Asian dust. Based on Nd–Sr isotopic ranges, the source regions can be divided into four isotopic regions: Region A1: the Gurbantunggut Desert in Junggar basin and Hunlun Buir sandy land in northeastern China; Region A2: the Hunshandake sandy land, Horqin sandy land and southern part of Mongolia; Region B: the Taklimakan Desert in Tarim basin, northeastern past of the Tibetan Plateau, Chinese Loess Plateau, Badain Jaran Desert and Tengger Desert in Alashan Plateau; Region C: the Hobq Desert and Mu Us Desert in the Ordos Plateau. Through comparison of Nd–Sr isotopes, it can be inferred that the sediments of the north-central Pacific and dust particles in the Greenland ice cores are mainly derived from Region B. Dusts of East Asian dust storm are derived mostly from Region B also, and less from Region A2. The materials of dust storm at Beijing area in April 2006, originated largely from the Hobq Desert and Mu Us Desert in the Ordos Plateau. The floating dust at Beijing area in April 2006, is the mixing of dust of distant deserts and local dust at Beijing area. Loess of the Chinese Loess Plateau may largely originate from Region B. 相似文献
540.