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1.
The adsorption behaviour of Diphenylamine (DPAM), napthylamine ( NAM), napthylamine ( NAM)and aniline on pyrolusite and activated carbon has been studied.Pyrolusite shows remarkable sorption capacity for DPAM and NAM as compared to aniline; (the adsorption followed theorder:Activated Carbon: DPAM = NAM > AnilinePyrolusite: DPAM: NAM > NAM> Aniline)The maximum adsorption of NAM occurred in theconcentration range 4–20 g mL-1 on pyrolusite (95%)and 4–50 g mL-1 on activated carbon (100%). Theeffect of various doses of activated carbon on the adsorption of NAM confirm Langmuir and Freundlich isotherms where asFreundlich isotherm is obeyed by pyrolusite. The adsorption of NAM on both the absorbents is not affected in presence ofDPAM over a wide range of their initial concentrations (20–60g mL-1). The desorption studies of NAM onpyrolusite was carried out by batch as well as column processes.Excellent results were obtained when a mixture of n-hexane andisopropanol (91:1) was used as eluent.  相似文献   

2.
Residues of organochlorines and organophosphates were determined by gas chromatography in water and sediment from 26 locations in 17 major rivers, 7 natural springs and 13 wells across Jamaica. Samples were collected on only one occasion between May and July, 1994. Residues of endosulfan were detected in all but three rivers; -endosulfan in 15 samples of sediment (0.9–108.1, mean = 28.93, S.E. = 7.198 g kg-1) and 13 of water (0.01–0.35, mean = 0.11, S.E. = 0.035 g L-1), -endosulfan in 5 sediment (15.29–49.35, mean = 30.56, S.E. = 7.132 g kg-1) and 12 water (0.05–0.31, mean = 0.14, S.E. = 0.031 g L-1) samples, and endosulfan sulphate in waters of three rivers (0.003–0.244 g L-1). Chlorpyrifos was present in 9 sediment (0.423-135.2, mean = 18.38, S.E. = 10.699 g kg-1) and two water (0.001–0.022 g L-1) samples, diazinon and ethoprophos in the sediment of one river each. Mean levels (g L-1) of and isomers and sulphate of endosulfan were 0.16 (S.E. = 0.057), 0.12 (S.E. = 0.036) and 0.15 (S.E. = 0.089), respectively, in four of the seven springs and 0.23 (S.E. = 0.052), 0.11 (S.E. = 0.029) and 0.26 (S.E. = 0.088), respectively, in seven of the thirteen wells monitored.  相似文献   

3.
Residues of endosulfan insecticide (-and -isomers, and endosulfan sulphate) were determined in the livers of catfish from a cotton growing area during the summer and winter of 1988. The concentration of total endosulfan residues found in the fish was up to 0.31 mg kg-1 wet wt. It decreased in winter with a maximum 0.02 mg kg-1 wet wt. The difference in endosulfan residues between seasons was statistically significant (ANOVA,p<0.01).  相似文献   

4.
The mean levels ± s.d., (ranges) of organochlorines, pesticides, chlorobenzenes and polychlorinated biphenyl were determined in the livers of 100 Atlantic cod (Gadus morhua) caught off the east coast of Canada in 1980 and were as follows: PCB 1.71±0.90 (0.24–4.33); p,p-DDE 0.28±0.15 (0.01–0.84); p,p-DDD 0.10±0.09 (trace-0.84); p,p-DDT 0.15±0.09 (ND-0.58); -HCH 0.06±0.02 (trace-0.10); -HCH (ND-trace); heptachlor 0.02±0.01 (ND-0.04); heptachlor epoxide 0.15±0.37 (ND-2.16); dieldrin 0.06±0.11 (ND-0.71); hexachlorobenzene 0.02±0.01 (trace-0.05) mg kg–1 (wet wt.). The levels of these compounds in 1980 have not changed over the previous eight years with the exception of PCB and the DDT group where there appears to be a general decline between 1972 and 1975 with no significant change thereafter.  相似文献   

5.
Concentrations of polychlorinated biphenyls (PCBs), DDT and its metabolites, HCH isomers and hexachlorobenzene (HCB) were determined in fish and birds from different locations in the Biobio river basin (central Chile). Samples collected near the mouth of the river contained high concentrations of PCBs, reflecting the massive use of these xenobiotics in the urban and industrial areas of Concepcion and Talcauano. Samples collected in the central part of the basin contained very high concentrations of lindane that coincide with the widespread use of lindane-based pesticides (purified -HCH) in this area. DDT was distributed homogeneously throughout the basin, except at Laguna Icalma, the source of the river in the Andes. Most PCB residues in fish and birds consisted of congeners between penta- and hepta-chlorobiphenyls. In fish, the predominant congeners were the pentachlorobiphenyl 23445 (IUPAC number 118) and the hexachlorobiphenyl 2234455 (PCB-153); in birds 224455 (PCB-180) prevailed.  相似文献   

6.
This report presents the results of an ozone monitoring experience performed with tobacco indicator plants (Nicotiana tabacum L. cv. Bel-W3). These bioindicators were exposed to ambient air in 23 sites in Northern Italy from 27 April 1987 to 21 October 1987. Typical ozone-induced leaf necrosis was observed in every site. The percentage increase in injured leaf area was estimated weekly and a Leaf Injury Index (LII) was calculated. The weekly series of LIIs were statistically inspected for spatial and temporal relationships. Sample correlation coefficients were statistically significant for almost every possible pair of sites. The time series properties of ten series of LIIs with no missing data were analyzed using Box-Jenkins models. An autoregressive first order model, or AR(1), was selected to remove the autocorrelation from these series. Linear correlation coefficients between prewhitened (i.e. from which autocorrelation had been removed) pairs of LII series were statistically significant. Hence synchronous variations in leaf necrosis could only be related to the regional diffusion of tropospheric ozone.Work carried out as part of the research programme: ENEL's contribution to the knowledge of important environmental issues, Research line; Effects of atmospheric pollution on the land.  相似文献   

7.
Only organochlorine (OC) residues were monitored by gas chromatographyin water, sediment and shrimp samples collected everymonth between July 1982 and August 1983 from therivers of Rio Cobre basin. In samples collected everyfour months during 1989–1990, and seven times duringJuly 1995–March 1996, OC and OP (organophosphates)residues were monitored. Carbamate and pyrethroidresidues were not monitored. The detection ofresidues in 1982–1983 was 54 to 100% in water andsediment, and 83 to 100% in shrimp samples fromvarious sampling stations in the four rivers. In otheryears, it ranged from about 40 to 100% in the threetypes of samples.In 1982–1983, DDE and dieldrin residues were found tobe much higher than those of lindane and - and-endosulfan in Black River, Rio Pedro, ThomasRiver and Rio Cobre in the watershed. The ranges ofmeans of each residue in water (g L-1), sediment(ng g-1) and shrimp (ng g-1) samples, respectively, were:DDE, 0.059–102.0, 3.44–13.97, 0.344–14.57;dieldrin, 0.026–173.6, 1.21–2.75, 0.427–5.59;-endosulfan, bdl, 1.75–4.00, bdl;-endosulfan, bdl (below detectable limits), 2.51–9.48, bdl;and lindane, (bdl), 0.110–0.319, 2.90.In 1989–1990 and 1995–1996, residues of six OCs and two OPs were detected quite regularly. DDE, dieldrinand Chlorpyrifos residues were much higher than thoseof the other insecticides. The range of their meansin water (g L-1), sediment and shrimp (ng g-1),respectively, were: DDE, 1.66–19.76, 0.941–5.84,1.11–8.32; dieldrin, 0.077–7.22, 0.425–3.31,0.385–1.59; -endosulfan, 0.034–1.25, 0.021–1.22, 0.032–3.62; -endosulfan, 0.665–1.23,0.008–3.60, 0.005–3.97; endosulfan sulphate, 0.959–1.34, 0.035–3.08, 0.012–1.80; lindane, bdl,0.005–0.82, 1.19–1.56; chlorpyrifos, 0.702–4.06,0.005–1.51, 0.156–7.04; and diazinon, bdl, 0–0.150, 0.001–0.006. At the mouth of the river, whereit discharges into the sea, the levels of almost allthe residues were higher than upstream.  相似文献   

8.
Tobacco plants (Nicotiana tabacum L. cv. Bel-W3) were exposed to ambient air for 25 weeks during the 1987 growing season next to an air pollution monitoring station in Brera (Milan, Italy). The research objective was to study the influence of selected environmental parameters on leaf damage in this plant, which is widely used as an ozone indicator. A multiple linear correlation model was estimated between leaf damage and available meteorological and air pollution data. Leaf injury was positively correlated with ozone integrated exposure and temperature, but negatively with vapour pressure deficit. A linear correlation model was used to estimate ozone integrated exposure from the leaf injury indexWork carried out as part of the research programme: ENEL's contribution to the knowledge of important environmental issues, research line: Effects of atmospheric pollution on the land.  相似文献   

9.
10.
Organochlorinated Compounds in Waters of the Pearl River Delta Region   总被引:4,自引:0,他引:4  
Samples of river water and sewage water were analysed for ten PCB congeners, chlorobenzenes and chlorinated pesticides (BHCs and DDT) in three cities (Guangzhou, Shenzhen and Zhaoqing) in the Pearl River Delta, The results showed that the sewage water in Shengzhen had the highest concentration of total PCBs at about 10ng/L, and Dasha River (Shengzhen), the lowest at about 1.0ng/L. In general, the sewage waters in the three cities had higher concentrations of PCBs than river waters. Chlorobenzenes were investigated in the water samples. The total concentrations of chlorobenzenes ranged from 0.02~0.13g/L, the Dasha River had the highest level of chlorobenzenes, and the sewage water in the city of Zhaoqing had the next highest. The result may be related to the discharges from paper production factories nearby the sampling sections of the Dasha River (Shenzhen) and sewage water in Zhaoqing. The concentrations of organochlorinated pesticides (-BHC, -BHC, -BHC, DDT and DDE) changed little in all water samples except for the sewage water in Guangzhou. It seemed that these pesticides are more a residual signal than a direct discharge from point sources.  相似文献   

11.
Although exposure assessments cannot be completed remotely, remote sensing techniques provide an invaluable adjunct in exposure monitoring programs. Exposure can be defined as the summation over time, in all media, of the amount of a pollutant available at the exchange boundaries of the receptor during a specified period. This paper describes a few remote monitoring techniques that provide direct measurement input into an exposure assessment and several that furnish quantitative or qualitative information leading to decisions regarding how to monitor, such that the source-exposure-dose relationships can be fully defined. Two general classes of remote sensing systems are included in this discussion-passive and active. Passive systems depend on a measurement of the energy reflected or emitted by a target and active systems use an energy source, e.g., a laser to perform the environmental interrogation. Airborne as well as ground-based remote monitoring measurements or systems are also considered in this paper.  相似文献   

12.
Many organic pollutants potentially are available for uptake by plants and thus bioaccumulation and food contamination. One method of studying uptake is with excised roots, a technique extensively used with plant nutrients. A similar method was developed and used to evaluate uptake patterns of several 14C-labeled organic chemicals. Uptake rate constants for the chemicals tested occurred in the following order: captan phenol > aniline > ethanol indole trifluralin propanil > 1,2,4-trichlorobenzene (TCB) > nitrobenzene atrazine > bromacil > simazine > monuron.  相似文献   

13.
Methane concentrations and stable carbon isotope ratios of water samples from the East Pacific Rise (EPR) at 21°S and the Arabian Sea (24°N, 65°E) have been determined. EPR surface water is in equilibrium (ca. 50 nl/L and –50<13CH4<–46) with atmospheric methane. Deep background water has the signature of the remaining fraction of atmospheric methane partially oxidized in the water column by bacteria. Bottom near, hydrothermally influenced vent methane (>100nl/L and –30<13CH4<–22) is detectable only close to the seep site. There is no input of hydrothermal methane into the atmosphere. EPR water is considered to be rather a sink than a source of atmospheric methane. Surface waters of the Arabian Sea are enriched in methane relative to the atmosphere (source for atmospheric methane). Carbon isotope ratios point to a bacterial origin of methane (13CH4<–55) that is generated in the surface waters. Concentration changes and variations of carbon isotope ratios also suggest that methane seeping from the sea floor sediments of the Arabian Sea is oxidized by bacterial activity and does not reach the atmosphere.  相似文献   

14.
The difficulty of measuring 15N in dilute solutions has limited the potential of ecosystem labeling experiments and model comparisons. By concentrating the N from large (up to 20 L) water samples on ion-exchange resin columns, we obtained enough N for accurate and reproducible 15N measurement using the Teflon tape diffusion method. Analysis of standards demonstrated >95% recovery of inorganic N from samples, and 15N values comparable to those obtained using standard distillation methods. The value of the blank at our laboratory was 0.16 moles N. Analytical precision was within 2 15N when samples of streamwater from the Bear Brook Watersheds (1800 eq · ha-1 · yr-1 N addition at 192 15N) were kept frozen until analysis. The analytical process is lengthy, but once set up can easily be performed for large numbers of samples.  相似文献   

15.
The simultaneous behaviour of seven ecological indices(Hurlberts, Margalefs, Menhinicks, Shannons,species number, Jaccards and saprobic index) wasstudied based on phytoplankton data close to the shoreon the East coast of Sweden during the summer 1998.The sampling stations had a similar eutrophicationlevel and were located in bays. Standard phytoplanktondatabases were used in calculating the indices, whichwere later compared using cluster analysis.Hurlberts, Margalefs, Menhinicks, Shannons andspecies number indices, as measure of communitydiversity, produced similar trends which oftendiffered from those based on Jaccards index ofsimilarity. However, the simultaneous use of theseindices was found meaningful as a possible part of themonitoring close to the shore. The application of asaprobic index lead to erroneous conclusions in thestudied case.  相似文献   

16.
In the U.K., local authorities have new duties to review and assess air quality. Dispersion models are important tools in this process. The performance of a street canyon model, AEOLIUS, in calculating carbon monoxide (CO) concentrations in urban areas is discussed. A field experiment was conducted in a busy street canyon in Leek, Staffordshire. Wind speed and direction were measured at three heights adjacent to the street. The canyon's CO concentrations and traffic counts were recorded. Predicted concentrations of CO, calculated using AEOLIUS, were compared with the observed values. The concept of a roof-top wind is discussed, as are the consequences of using wind measurements from outside the town. Choice of wind measurement location and height of the anemometer above the canyon had a pronounced effect on calculating the roof-top wind. Two methods of deriving a street level wind speed from a roof-top wind speed gave results that differ by up to a factor of two. AEOLIUS had variable skill at predicting CO concentrations depending on the roof-top wind direction: possible reasons for this variability are explored. A sensitivity study of the model showed that vehicle emissions have the greatest impact on predicted concentrations. Implications for local air quality management are discussed.  相似文献   

17.
The Niepoomice Forest is a large forestcomplex (110 km2) situated in southern Poland 10 to 30 kmto the east of the urban industrial Kraków agglomeration andsteelworks, which was built up on the outskirts of the city in1950. Due to prevailing westerly winds, the forest is affectedby pollutants emitted by both the steelworks and the city. Thelevel of heavy metal contamination in the Niepoomice Forestwas described using a sensitive bioindicator – the moss Pleurozium schreberi. Mean concentrations of metals in mosscollected in the Niepoomice Forest were Cd – 0.71, Cr – 2.4,Cu – 8.6, Fe – 673, Pb – 12.7, and Zn – 61 mg/kg.Concentrations of heavy metals in moss in the NiepoomiceForest decreased in time. As compared with the relatively cleanarea in north-eastern Poland (Puszcza Biaowieska), the concentration of Fe was 2–9 fold and Pb 4–6 fold higher in theNiepoomice Forest in 1975, while in 1998 4 fold and 2 fold,respectively. In both 1975 and 1998 the most polluted by heavymetals was the western part of the Niepoomice Forest (closestto the pollution sources) and the area along the roads insidethe forest complex.  相似文献   

18.
Different urban air pollution problems deal with complex structure of air flows and turbulence. For such problems the Computer Fluid Dynamics (CFD) methods become widely used. However, this approach despite a number of advantages has some problems. Experience of use of CFD tools for development of models and suggestions of their applications for a local scale air pollution over a complex terrain and stable stratification are discussed in this paper, including: Topography and complex geometry: choose of the co-ordinate system and computer grid; Turbulence closure for air pollution modelling: modified k- model for stable stratified ABL; Boundary conditions for vertical profiles of velocity for stable-stratified atmosphere; Effects of the radiation and thermal budget of inclined surfaces to dispersion of pollutants; Artificial sources of air dynamics and circulation.Some examples of CFD applications for air pollution modelling for a flat terrain, mountainous area, mining open cast and indoor ventilation are discussed. Modified k- model for stably-stratified ABL is suggested. Due to the isotropic character of the k- model a combination of it in vertical with the sub-grid turbulence closure in horizontal can be more suitable for ABL. An effective scheme of boundary conditions for velocity profiles, based on the developed similarity theory for stable-stratified ABL, is suggested. Alongside with the common studies of atmospheric dispersion, the CFD methods have also demonstrated a good potential for studying anthropogenic and artificial-ventilation sources of air dynamic and circulation in local-scale processes of air pollution.  相似文献   

19.
This paper aims to assess the consequences of the amendments made to the Kyoto Protocol during COP 7 in Marrakech. The major issue of hot air and CDM transaction costs is examined using the CERT model to show that primary supply regions, typically those with hot air availability, might control the emissions reduction permit supply market and maximise net export revenues of permit supply by withholding 40 to 60% of available hot air credits. The assumption that primary permit suppliers control permit price via a restriction of hot air supply to the market will inadvertently leave a portion of the market share open to non-Annex B CDM supply, despite potentially extreme variance in CDM transaction costs. A summary table of policy implications on the emissions reduction permit market is also included.  相似文献   

20.
The nature of atmospheric aerosols at Gurushikar, Mt. Abu, Rajasthan where a gamma ray telescope is to be installed, was investigated. Air particulate samples collected on filters were used to estimate the total suspended particulate matter (TSPM) and its elemental composition. The TSPM varied from 31 to 103 g/m3 during January to March 1994. The heighest loads were observed during the months of May and June (80–100 g/m3) and lowest during October (20–60 g/m3). The dust was also examined for size, shape and nature of the mineral matter. The particle sizes varied from 100 m to 5 m. The course particles (>50 m) are irregular shaped quartz grains. Some of the medium size (=50 m) particles were spherical and were highly conducting. These particles were rich in iron content. Correlation coefficients among various elements in the dust showed that it is made up of mainly two components-wind blown ground dust and particulate arising out of wood and coal burning.  相似文献   

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