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1.
Water samples, collected trimonthly along the Uruguay River between February 1988 and December 1989, were analyzed for alpha- and gamma-HCH, heptachlor and its epoxide, aldrin, dieldrin, and the o-p′ and p-p′ isomers of DDE, DDD and DDT to assess the present status of the contamination in this South American region. In general, chlorinated pesticides were encountered at very low concentrations. HCH isomers were the most commonly detected compounds with concentrations ranging from the detection limits to 10 ng L?1. Heptachlor, heptachlor epoxide, aldrin, dieldrin, p-p′ DDE and p-p′ DDT were occasionally encountered while o-p′ DDE, p-p′ DDD, o-p′ DDD and o-p′ DDT were never detected. Compared to previous studies in the area, the present data seems to indicate that there was a decrease in the concentrations of these compounds.  相似文献   

2.
The concentration of organochlorine insecticides/metabolites, namely, lindane, heptachlor, aldrin, p,p′-DDL, p,p′-DDD, and p,p′-DDT were determined in water samples taken from two lakes, Jalmahal and Mahalon, from June 1985 to July 1986. These lakes are contaminated with moderate to high level of residues of different insecticides. In Mahalon lake the residues were highest (6.6 μg L?1) during October 1985 whereas in Jalmahal lake they were highest (9.6 μg L?1) in September 1985. In both lakes, residues of DDT exceeded the recommended limit for water quality criteria. Lindane was found in most of the samples but in lower quantities. Aldrin was the second most common residue in these lakes.  相似文献   

3.
Water samples from twelve wells on the coastal aquifer of Israel were analyzed for γ-BHC (lindane), α-BHC, aldrin, o.p1.DDD, p.p1.DDT, dieldrin, heptachlor and heptachlor-epoxide. Lindane was found in five wells with concentrations ranging from traces to 15 ppt. α-BHC was detected in one well (4 ppt). None of the other pesticides could be detected. The wells where lindane was detected were between 13 m and 26 m deep and the soil above the water table was sandy. Lindane occurrence is attributed to heavy localized applications and downward movement of water in considerable quantities. Analysis of the potential mobility of lindane indicates that it can be rather mobile in sandy soils.  相似文献   

4.
Aquatic mosses have been used to study four accidental discharges of the heavy metals Cd, Zn and Hg or the chlorinated hydrocarbons pentachlorophenol (PCP) and lindane in highly contrasting river types. Hg, PCP and lindane moss concentrations reached 880, 4500 and 350 ng g?1, respectively. In the case of Cd and Zn, water samples and transferred bioindicators were taken simultaneously throughout an accidental discharge. The very high dissolved metal concentrations reached during this accident (9 mg L?1 Zn, 90 μg L?1 Cd) induced accumulation by the mosses of up to 28 mg g?1 for Zn and 225 μg g?1 for Cd. The increase in concentrations in the mosses was as rapid and substantial as in the water, the time lag due to accumulation kinetics being almost zero. On the other hand, the memory effect enabled mosses to retain marked evidence of Cd, Zn, Hg, PCP and lindane up to 13 days after the accident when difference from background levels can hardly be detected in the water. The four case studies, which killed fish, but not the mosses, show that the previously established scales of quality based on the analysis of aquatic mosses are well suited to estimating the potential damage to the aquatic ecosystem as a whole.  相似文献   

5.
The 48 and 96-hr LC50 values of Pb (Pb(NO3)2) with O. niloticus were 3.34 and 2.15 mg L?1, respectively, compared to 1.91 and 1.72 mg L?1, respectively, for C. lazera. C. tentans larvae and Benacus sp. demonstrated 48-hr LC 50 of 2.68 and 1.89 mg l?1 respectively. The 96-hr LC50 value was 1.77 mg L?1 for Chironomus and 1.36 mg L?1 for Benacus. Clarias appeared to be the most susceptible of the four to Pb poisoning; Chironomus being the least susceptible. Uptake pattern of Pb by fingerlings of O. niloticus and C. lazera exposed to 0.33 and 0.27 mg L?1 Pb, respectively, and the clearance of accumulated Pb were curvilinear. There was an initial ‘fast’ phase of accumulation occurring during the first 96 hr, followed by a slower phase over the remaining 240 hr. Mean Pb concentrations in gills, intestine, liver, muscle, bone, skin and whole body of O. niloticus were 33.30, 22.2, 5.3, 2.8, 1.8 and 14.9 μg g?1, respectively, compared to 28.7, 6.5, 11.5, 2.5, 5.6, 5.9 and 6.8 µg g?1 respectively in C. lazera. The half life of Pb in Oreochromis was 20 hr compared to 43 hr in C. lazera. Bioconcentration factors in Oreochromis and Clarias were 78.3 and 33.8, respectively. The data suggest that O. niloticus accumulates and eliminates Pb faster than C. lazera.  相似文献   

6.
Clarias anguillaris and Oreochromis niloticus were each exposed to solutions of Analar grade Cu sulphate in static bioassays at a temperature range of 20 to 23.5°C and CaCO3 hardness of 30 to 44 mg L?1. Copper accumulation was determined by Atomic Absorption Spectroscopy. The Cu residues in Clarias anguillaris exposed to 0.027, 0.055, and 0.11 mg Cu L?1. for 8 weeks were 15.7, 21.8, and 31.17 mg g?1 dry weight, respectively. Oreochromis niloticus exposed to 0.05, 0.1 and 0.2 mg Cu L?1. accumulated 34.69, 36.09, and 81.03 mg g?1 dry weight, respectively, over the 8-week period of exposure. The lowest and highest bioconcentration factors (BCF) were 117 and 581 for Clarias anguillaris and, 176 and 694 for Oreochromis niloticus. Copper concentrations in tissues of both species were directly related to the exposure concentrations and the duration of exposure. Increased accumulation towards the last 2 weeks of exposure may be due to impaired capacity of elimination or poor nutritional status.  相似文献   

7.
The extent of pollution with organotin compounds was investigated in water, sediment and bivalve mussels (Mytilus galloprovincialis) from the Northern Adriatic Sea. Butyl-, phenyl- and octyltin species were quantified after extraction and derivatisation by gas chromatography–mass spectrometry in a total of 99 samples from the period from 2000 to 2006. The accuracies of the analytical procedures were checked by spiking of unpolluted water samples and by the analysis of standard reference materials (harbour sediment PACS-2 and mussel tissue ERM-CE 477). Among organotin species analysed in samples butyltins were the predominant. Tributyltin was found to be present in the highest concentrations, suggesting its recent input into the marine environment. Butyltins were detected at all sites surveyed (sum of butyltins was up to 718 ng Sn L?1, 3,552 ng Sn g?1 d.w. and 9,991 ng Sn g?1 d.w. in water, sediment and mussel samples, respectively), phenytins in much lower concentrations (up to 31 ng Sn L?1, 326 ng Sn g?1 d.w. and 442 ng Sn g?1 d.w. in water, sediment and mussel samples) and to a much smaller extent, while octyltins were not detected at any location. The spatial distribution of tributyltin was closely related to boating, with the highest concentrations found in marinas (up to 586 ng Sn L?1 for water samples, 1,995 ng Sn g?1 d.w. for sediment and 6,434 ng Sn g?1 d.w. for mussel samples). The temporal distribution clearly indicates a decrease of organotin pollution at all sites.  相似文献   

8.
The toxic effects and accumulation of the heavy metals, Cd, Cu, and Zn by the sheath forming blue-green alga Chroococcus paris were investigated. All three of the metals were bound rapidly. Approximately 90% of the total amount of the added metal was bound within 1 min. Further significant binding occurred at a slower rate. The maximum metal binding capacity, as determined by filtration studies, was determined to be 53, 120, and 65 mg g?1 dry algal weight for Cd, Cu, and Zn, respectively. Binding curves for the metals followed the Langmuir adsorption isotherm model. The amount of metal bound increased with increasing pH. Metal binding increased significantly when pH was increased from 4 to 7. Nearly all of the metal was found to be rapidly EDTA extractable. Metals were found to be increasingly toxic to growing cultures in the order, Zn, Cd, and Cu. All of the metals studied exhibited toxic effects at concentrations greater than 1.0 mg L?1. The lowest concentrations used which showed detectable toxicity were 0.1 mg L?1 for Cu and >0.4 mg L?1 for Cd and Zn.  相似文献   

9.
Tetrahymena pyriformis, a common freshwater ciliate concentrated the four common HCH (Hexachlorocyclohexane) isomers viz., α, β, δ, and γ to varied extent. Bioconcentration factor [as expressed by the ratio of cellular insecticide in ng mg?1 (dry weight) to supernatant in ng μL?1 ranged from 342 to 2260 for α-HCH, 37 to 831 for β-HCH, 326 to 2806 for δ-HCH and from 106 to 1214 ppm for γ-HCH.  相似文献   

10.
The hydrobiological parameters of the waters in the vicinity of ash slurry and cooling water outfall from Ennore Thermal Power Station located on the shore of Bay of Bengal, Madras were determined. In the outfall site, an increase in mean temperature (35 °C), salinity (3.5%), nitrite ? N (25 μg L?1), ammonia ? N (185 μg L?1), phosphate ? P (1 mg L?1), silicate ? SiO2 (1.65 mg L?1), chlorophyll a (21.1 mg m?3), respiration (76% of gross production), suspended solids (3.84 g L?1), BOD (3.65 mg O2) and decrease in pH (8.1), dissolved oxygen (DO) (5.5 mg L?1), nitrate ? N (15 jig L?1), gross production (16.6 Mg C m?3 hr?1) were recorded. Phaeopigment and respiration were inversely related with chlorophyll a and net productivity, respectively. Microbial biomass varied spatially, but was generally low (114.5 jig L?1), at the outfall site. The hydrobiological characteristics of water with high turbidity indicate that the ash slurry and coolant water play a crucial role in a localized area resulting in environmental disturbance. The effect was profoundly influenced by an initial dilution, dispersion, wave mixing and current direction. The ecological relationships between these parameters and their implications in coastal pollution are discussed.  相似文献   

11.
Levels of trace metals and chlorinated hydrocarbons were determined in sludge produced at the three main wastewater treatment plants in Kuwait (Ardhiya, Jahra, and Reqqa). Over the 6 mo study period (October 1984 to March 1985) levels at the three plants showed the following ranges (μg g?1 dry weight); Cd, 0.5 to 5.0; Cu, 90 to 270; Zn, 1100 to 3000; Pb, 80 to 300; Ni, 25 to 60; Hg, 1.8 to 3.6; Ag, 1 to 35; PCBs, 0.1 to 3.6; lindane, 0.4 to 7.4; EDDT (i.e., DDT + DDD + DDE), 0.07 to 0.20; aldrin, below detection to 0.07; endrin, below detection to 0.27; dieldrin, 0.005 to 0.04). Mean levels were generally close or lower than mean concentrations reported in the United Kingdom and the United States. They were also lower than suggested concentration limits for application of sludge on agricultural land, which is one of the most cost-effective and attractive techniques for sludge disposal. For Kuwait to adopt this application, however, the characteristics of the local soil and prevailing environmental conditions, notably the frequent occurrence of severe dust storms, should be considered.  相似文献   

12.
Chestnut agro-industrial companies consume a high volume of water for washing and processing fruit, generating a large volume of wastewater. This work studied the biodegradation of chestnut processing wastewater through aerobic assays, varying substrate, and biomass concentrations. In general, this wastewater presents a good biodegradability, especially in experiments with relatively low chemical oxygen demand (COD) (0.4 and 0.6?g O2 L?1) allowing a COD removal of 85?C90?%. The best results were obtained in the reactor initially loaded with 2?g?L?1 of biomass and 0.4 or 0.6?g O2 L?1 of COD. These experiments also showed high COD removal rates: 4.25 and 3.88?g COD g?1 volatile suspended solids (VSS) h?1, respectively. The sedimentation rate, evaluated for different initial values of biomass (1, 2, and 3?g?L?1), always presented higher values in the experiments with 2 and 3?g?L?1 of biomass, regardless of the initial COD value used. After comparing different kinetic models (Monod, Contois, and Haldane), it was observed that the Haldane inhibition model satisfactorily describes the COD biodegradation. AQUASIM software allowed calculating the kinetic constant ranges: K s, 1.59?C6.99?g COD L?1; ?? max, 25?C40?g COD g?1 VSS day?1; and K i values, 0.07?C0.11. These kinetic constants corresponds to maximum rates (??*) between 1.48 and 4.25?g COD g?1 VSS day?1 for substrate concentrations (S*) from 0.38 to 0.88?g COD L?1.  相似文献   

13.
Both Pb(II) and UO2 2+ were abstracted from aqueous solution by both living and dead biomasses of Streptomyces sp. The organisms were particularly effective in taking up UO2 2+ ions. Optimum pH for both metals was pH 5 to 6. For a UO2 2+ concentrations of 1 mmol L?1 and a dead biomass concentration of 1 g L?1, 60% of the UO2 2+ was removed from solution. If cell wall material of the organism was prepared from a killed biomass an equal weight of the material removed 90% of the UO2 2+ from solution. in this case accumulated U in the biomass was 0.9 mmol g?1 of dry biomass. Electron micrographs showed clearly that the Pb abstracted was only in the microorganisms cell surface, but UO2 2+ uptake was also intracellular.  相似文献   

14.
Avoidance responses of an estuarine fish, mummichog (Fundulus heteroclitus), and crustacean, grass shrimp (Palaemonetes pugio) to the antifoulant his (tri-n-butyltin) oxide (TBTO) were evaluated. Four out of six groups of mummichogs tested at 1.0 μg total organic Sn L?1 showed avoidance. Total organic Sn concentrations of ≥ 3.7 μg L?1 were avoided by this fish species in all cases. Higher concentrations of total organic Sn did not result in greater avoidance responses. Grass shrimp did not avoid total organic Sn concentrations between 2.3 and 30.0 μg L?1. Response data at 2.3 and 30 μg L?1 were similar. Mummichogs and grass shrimp differed greatly in their abilities to avoid potentially adverse concentrations of total organic Sn. Since mummichogs are major predators of grass shrimp, these behavioral responses may have important implications for tidal marsh ecosystems.  相似文献   

15.
Litterfall can be an important flux of mercury (Hg) to soils in forested landscapes, yet typically the only available data to evaluate Hg deposition is from precipitation Hg monitoring. Litterfall was collected at 39 sampling sites in two small research watersheds, in 2003 and 2004, and analyzed for total Hg. Four vegetation classes were designated in this study as hardwoods, softwoods, mixed and scrub. The mean litter Hg concentration in softwoods (58.8 ± 3.3 ng Hg g?1 was significantly greater than in mixed (41.7 ± 2.8 ng Hg g?1 and scrub (40.6 ± 2.7 ng Hg g?1, and significantly lower than in hardwoods (31.6 ± 2.6 ng Hg g?1. In contrast, the mean weighted litter Hg flux was not significantly different among vegetation classes. The lack of a significant difference in litter Hg flux between hardwoods and softwoods was attributable to the large autumnal hardwood litter Hg flux being balanced by the higher softwood litter Hg concentrations, along with the higher chronic litterfall flux throughout the winter and spring in softwoods. The estimated annual deposition of Hg via litterfall in Hadlock Brook watershed (10.1 μg m?2 and Cadillac Brook watershed (10.0 μg m?2 was greater than precipitation Hg deposition and similar to or greater than the magnitude of Hg deposition via throughfall. These results demonstrate that litterfall Hg flux to forested landscapes can be at least as important as precipitation Hg inputs.  相似文献   

16.
Created wetlands offer a low cost, low maintenance, and practical alternative for upgrading secondary municipal wastewater treatment systems. The removal efficiencies, effects of seasonal temperature variations, and effects of increased loading rates on contaminant removal within such a system was studied by Auburn University researchers at a created wetland site in Hurtsboro, Alabama. The 0.16 ha system consisted of a two cell wetlands planted with cattails (Typha latifolia), bulrush (Scirpus validus), arrow duck potatoes (Sagitaria latifolis), burr reeds (Spargaminum eurycarpun), water pennywort (Hydrocotyl ranunculoides), and parrotfeather (Myriophyllum brasiliense). Testing occurred from January through September of 1988 at hydraulic loading rates of 169, 289, and 345 m3 ha?1 d?1. The monthly average total suspended solids influent: effluent mg L?1 concentration ratio during the study period was 135:19 while the monthly average total BOD5 influent: effluent mg L?1 concentration ratio was 38:8. Once the system stabilized, the monthly average total BOD5 effluent concentration remained essentially constant over the range of average BOD5 loading rates employed in this study. Total Kjeldahl N removal was more effective at loading rates of 2.6 kg ha?1 d?1. The monthly average influent: effluent TKN mg L?1 concentration ratio was 15:4.  相似文献   

17.
The concentrations of Al in fish gills has been used as a measure of fish exposure to this metal in acidified waters. This experiment was designed to determine if other fish tissues also accumulate Al and thus possibly contribute to the cause of death. Rainbow trout (Salmo gairdneri) were exposed to the following fours test conditions for 48 hr or until death: (1) pH 6.8, <0.001 mg.L?1 Al (n=6); (2) pH 5.2, <0.001 mg1L?1 Al (n=2);(3) pH 5.2,1.0 mg.L?1 Al (n=5); (4) pH 6.8, 1.0 mg.L?1 Al (n=3). The trout were held in synthetic, low Ca water prior to, and during, experimentation. Esophagus-stomach, gonad, gall bladder, gill (left and right), heart, intestine, kidney, liver, muscle (epaxial), and spleen were digested in a 4:1 mixture of HNO3:HClO4 and analyzed by Inductively Coupled Plasma Emission Spectrophotometry. Elevated Al concentrations were found in gill and gastrointestinal tissues. Left and right gills of fish exposed to pH 5.2, 1.0 mg.L?1 Al were the only tissues found to be significantly different (p<0.01) between the test conditions. The mean total Al concentrations of these test 3 fish, for the left and right gill were 3.61 and 4.33 mg.g?1 Al dw. The Al concentration in thle gastrointestinal tissues of the fish exposed to pH 6.8 at 1.0 mg.L?1 Al was greater than that of the control fish, but not statistically significant. These results suggest that the analysis of whole gill remains an effective indicator of Al exposure in fishes at low pH.  相似文献   

18.
Three months after neutralization concentrations of methylmercury (MeHg) were higher in the water of the limed than in the control basin of a small lake. After two years, the concentrations in the limed basin were somewhat lower than in the control (0.056–2.19 ng L?1 and 0.129–2.65 ng L?1, respectively). The highest concentrations were found in the anoxic hypolimnia. The total amount of MeHg in the water mass of the lake varied from 19 to 68 mg, showing a drop after spring and autumn overturns and a maximum during stratification periods. The total Hg concentrations of fish in L. Iso Valkjärvi varied from 0.06 to 0.14 μg g?1 (ww) in whitefish to 0.1 to 0.7 μg g?1 in perch and to 0.2 to 1.4 μg g?1 in pike. The total amount of MeHg bound in the fish of the lake was quite similar to that in the water column, 43 to 59 mg in 1990–1993, 33 to 47 mg of which was in the perch population.  相似文献   

19.
We analyzed surface waters from 30 Wisconsin lakes and rivers for total mercury ([Hg]T) and total suspended particulates (TSP) on a state-wide basis with trace-metal ‘ultraclean’ techniques. Mercury concentrations ranged from 0.3 to 2.9 ng L?1 in lakes and from 0.7 to 8.9 ng L?1 in rivers. TSP concentrations ranged from 0.9 to 6.6 mg L?1 in lakes and from 3.1 to 31.4 mg L?1 in rivers. Spatial trends were weak; however, [Hg] T was generally higher in the spring than in the autumn of 1991. Total mercury concentration was weakly dependent on TSP with the coefficient of determination (r 2) ranging 0.06 to 0.49 across seasonal and geophysical differences.  相似文献   

20.
The effects of selenium (Se) (VI) soil fertilization with 2 μg Se L?1 or foliar spraying twice with 20 mg Se L?1 in the form of sodium (Na) selenate on the physiological and biochemical characteristics of cabbage plants were studied. The ability of the plants to take up Se and translocate it to different parts of the plants was also studied. Despite the high concentration of Se in the foliar solution, there was no effect on photosynthesis, transpiration rate, photochemical efficiency of PSII, or electron transport system activity. The amount of chlorophyll and anthocyanins were unchanged. At harvest, the concentration of Se in control plants was lower than 100 ng Se g?1 dry weight (DW), while plants treated with 20 mg Se L?1 contained 5500 ng Se g?1. Selenium enriched cabbage could be used in human nutrition. The tolerance of cabbage to Se could be explained by the formation of insoluble compounds that are not available for the plant.  相似文献   

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