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1.
A method to determine pyrophosphate (PP) and tripolyphosphate (TPP) in sediments was developed. Sediment was extracted with 2% EDTA + 0.1 M NH4F followed by a second extract of 2% EDTA + 1 N NaOH. Orthophosphate (OP), PP, and TPP were separated by anion exchange chromatography, the fractions collected, and P determined after extraction into isobutanol. The limit of detection of the method was 0.5 μg P g?1 sediment. Fourteen sediments were tested and the highest TPP found was 1.8 μg P g?1 sediment. Thirteen of the sediment samples contained less than 1 μg P g?1 as TPP. Only three of the 14 samples contained more than 1 μg P g?1 as PP. The highest level of PP (8.5 μg P g?1) was found in sediment from an animal waste lagoon. Estimates of error and reproducibility were made from analysis of samples with added PP and TPP. The error for samples containing 36.9 μg P g?1 as PP was ± 7.6, and for TPP at 12.3 μg P g?1 the error was ± 3.3. The values for PP and TPP were underestimated by 6 and 36%, respectively.  相似文献   

2.
To help expand our global perspective on trace metal contamination, concentrations of Cu, Fe, Hg, Mn, Ni, Pb, and Zn were determined for sediments from the Ebrie Lagoon in the Ivory Coast, a developing West African nation. Excess loading of several metals, especially Hg, Pb, and Zn was found at several sites. The maximum concentration of Hg measured in sediments from the Ebrie Lagoon (2250 ng g?1) is about 30 times greater than natural levels. Similarly, Pb and Zn concentrations for the Ivorian lagoonal sediments are as high as 250 and 560 μg g?1, respectively, showing sizeable anthropogenic inputs. Trace metal sources to the Ebrie Lagoon include untreated sewage and industrial wastes.  相似文献   

3.
The herbicide glyphosate was sprayed aerially on a section of conifer forest in Atlantic Canada that had been previously clearcut and reforested. Glyphosate was then tested for effects on ammonification, nitrification, and denitrification for a period of 8 months by comparing microbial activity in treated and untreated zones of the clay loam forest soil and the overlying decomposing litter, both with a pH of 3.8. With ammonification, there was generally a stimulation of activity in both the forest litter (FL) and forest soil (FS) that had been exposed to glyphosate during spraying. Nitrification rates in FL and FS were very low and glyphosate had no appreciable stimulatory or inhibitory effect on nitrification. Although glyphosate stimulated denitrification in a few instances, it generally had no significant effect on denitrification activity in FL and FS exposed during spraying. With all processes, microbial activity in FL was significantly greater than that in FS. Laboratory bioassays were also performed with FL and FS, as well as two silt loam (pH 5.8 and 6.4) and one sandy loam (pH 6.8) agricultural soils, using glyphosate concentrations up to 200 times higher than field application rates. With ammonification and denitrification, glyphosate generally stimulated activity at all levels tested and in all soil used. Glyphosate stimulated ammonification by 50% at concentrations ranging from 140 to 550 μg g?1 for the soils and >4000 μg g?1 for FL. With denitrification, the corresponding herbicide levels were approximately 2250 μg g?1 for FS, > 10,000 for FL, and 450 for an agricultural soil. With nitrification, it was estimated that glyphosate concentrations greater than 1000 to 2000 μg g?1 would be required to cause a 50% inhibition of activity. The careful use of glyphosate in forestry should have no toxic effects on N cycling in soils.  相似文献   

4.
Samples of soils and vegetation from the mining area of South-West Sardinia (Italy) were analyzed for Pb, Zn, Cd, and Cu content. The area (more than 100 km2) is inhabited by many thousands of people; land utilization includes mainly grapes on some small plains and permanent sheep pasture on the hills. The levels of Pb, Zn, and Cd were found to be exceptionally high in most samples. Lead concentration was up to 71000 μg g?1 in the soils and 4000 jig g?1 in vegetation; Cd concentration was found up to 665 μg g?1 in soils and 26.5 μg g?1 in vegetation. The heavy metal content of some soil samples was highly variable. Data show that Pb is easily absorbed by plant roots and translocated to foliage. In spite of the high heavy metal level, no signs of toxicity were apparent in vegetation.  相似文献   

5.
A simple marine algal bioassay method is described for short- and long-term studies on pesticides and industrial wastes. It can be used for rapid screening of a variety of substances with single-species and multiplespecies tests and gives relative toxicities of the pollutants tested. Algae are grown in optically matched culture tubes that fit directly into a spectrophotometer, allowing population density to be estimated by absorbance without removal of samples. 96 h EC50 values for some pesticides and the diatomSkeletonema costatum are: EPN, 340 μg l?1; carbophenothion, 109 μg l?1; DEF, 366ug l?1; ethoprop, 8.4 mg l?1; methyl parathion, 5.3 mg l?1; and phorate, 1.3 mg l?1. Presence of the chelator EDTA in medium had no effect on toxicity of carbaryl toS. costatum, Nitzschia angularum, Chlorococcum sp. andChlorella sp. Liquid industrial wastes either stimulated growth, inhibited growth, or stimulated growth at low concentrations but inhibited it at higher concentrations. In mixed-species studies with the herbicide neburon, presence of a resistant species protected the sensitive species. Liquid industrial waste from a paper products plant caused changes in relative numbers, as compared to controls, whenS. costatum andPorphyridium cruentum were grown together.  相似文献   

6.
Mud crab larvae, Rhithropanopeus harrisii were exposed to tributyltin oxide, (TBTO) (0.5, 1, 5, 10, 15, or 25 μg l?1) or tributyltin sulfide (TBTS) (0.5, 1, 5, 20, 30, or 50 μg l?1). Differential survival was observed in TBTO concentrations equal to or greater than 10 gg l?1 and in TBTS concentrations equal to or greater than 20 μg l?1 Growth and development rate were assessed as sublethal indices of stress. Of the two, development rate was more sensitive. All groups exposed to either compound had slower development rates than controls. Growth of the larvae, as shown by weight gain, was slightly increased in low exposures (a hormetic response) and decreased significantly in higher concentrations. The mean weight of the 50 μg l?1 TBTS group showed the largest decrease, to 57% of the control. The hormesis response was further examined by measuring daily growth of the zoeae. All groups exposed to tributyltin compounds showed an initial growth lag. The hormesis response occurred in the fourth zoeal stage or megalops. While R. harrisii is relatively tolerant to the acute toxicity of tributyltin compounds compared to other marine crustaceans tested, sublethal responses occur in very low concentrations. This points to the need for analyses to characterize tributyltin environmental concentrations.  相似文献   

7.
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   

8.
Air pollution and atmospheric deposition by PCBs and organochlorine pesticides (isomers of HCH and p,p′-DDE) were studied at Paris from January 1986 to June 1987. The deposition measured as total (wet plus dry) was also followed during 1986 on two suburban and two rural sites. The distribution of the pollutants between the vapor phase and aerosols was evaluated by sampling air through a glass microfiber filter connected to a Tenax resin cartridge. The study shows that in the atmosphere as in waters of the catchment area of the Seine river, PCBs are the main organochlorine pollutants. Pollution by OCL is of the same order as the one described in literature (mean γ-HCH concentration 1.4 ng m?3) while PCB concentrations in the atmosphere are equal to or higher than those observed in USA and Europe (range 5 to 44 ng m?3). On the average, 93% of the PCBs are in the vapor phase with a composition approximating Aroclor 1242. In aerosols and precipitations the composition is closely related to Aroclor 1254. The total fallout for 1986 was 40 μg m?2 for PCBs and 20 μg m?2 for γ-HCH, rainfall being 611 mm.  相似文献   

9.
Sediment cores were taken from the remote Sagamore and Woods Lakes in New York State's Adirondack acid lake region and analyzed for 3 to 7 ring polycyclic aromatic hydrocarbons (PAHs) and Ag, Al, As, Be, Cd, Cr, Cu, Hg, Ni, Ph, Se, Sn, TI, V, and Zn. With the exception of perylene, all of the parental PAHs, e.g. those without sidechains, and several of the metals, Pb, As, and Cd, were found to be significantly increased in the sediments of both lakes compared to their natural integrated deposits (ng cm?2) and their background concentrations (μg g?1 or ng g?1 dry wt). Although the concentrations were generally much higher in Woods Lake, the total anthropogenic integrated depositions were about the same in both lakes for most of the metals and the 3 to 4 ring PAHs. The prime source of most of the 3 to 7 ring PAHs and trace elements measured is ascribed to anthropogenic combustion. Anthropogenically derived materials decreased in concentration with depth to baseline levels in sediment layers estimated by137Cs analyses to be ~30 yr old, while biogenic or crustal derived species remained constant or fluctuated with core depth.  相似文献   

10.
Litter decomposition was studied at two forested watersheds in east Tennessee which differed primarily in their past history of atmospheric S input. Cross Creek Watershed, located near a large coal-fired power plant, has received greater S inputs than the more remote Camp Branch Watershed. Decomposition was estimated through the measurement of forest floor respiration, litter microflora populations, litter and soil microarthropod populations, and litter nutrient status. Average forest floor respiration rates were very similar, 6.78 g CO2 m?2 day?1 or 2472 g m?2 yr?1 at Camp Branch and 6.86 g CO2 m?2 day?1 or 2505 g M?2 yr?1 at Cross Creek. Fractional loss rates provided estimates of annual decay rates (k) of 0.35 and 0.39 for Camp Branch and Cross Creek, respectively. Litter decomposition was estimated to contribute 23% of the total CO2 output at Camp Branch and 26% at Cross Creek, while root respiration accounts for about 43 to 46%. Bacterial and fungal populations were about equal in size at both watersheds, with bacteria averaging 100 × 106 g?1 of litter and fungi 23 × 106 g?1 of litter. Total numbers of arthropods averaged 34% greater at Camp Branch. Acarina populations averaged 59% higher at Camp Branch, while Collembola numbers were about equal at the two watersheds. Nutrient mobility in the litter and soil was similar at both watersheds. The order of decreasing mobility was K, Mg, Ca, S, N, and P. Litterfall nutrient concentrations were slightly higher for all elements at Cross Creek, resulting in greater litter concentrations of Ca and Mg. Litter concentrations of S and N, however, were significantly greater at Camp Branch, indicating watershed differences in the loss rates and cycling processes of these elements. There were no differences between the loss rates or litter concentrations of P, K, and Na at either site. Overall, decomposition was similar at the two watersheds. Historic S inputs do not appear to have had a major effect on decomposition rate or decomposer organisms with the possible exception of lowered arthropod populations at Cross Creek.  相似文献   

11.
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   

12.
Thirteen 1-L replicate water samples from streams emptying into Blanca Bay, Argentina, were taken to study the environmental quality of the surface waters. Out of tests for eleven chlorinated pesticides, five were detected in all the sampling places as both dissolved and adsorbed species: alpha-HCH, gamma-HCH (lindane), heptachlor, delta-HCH, and aldrin. The concentrations were in the following ranges: alpha-HCH = 3 to 68 ng L?1 and 9 to 239 ng g?1, lindane = 2 to 42 ng L?1 and 10 to 542 ng g?1, heptachlor = 5 to 32 ng L?1 and 9 to 390 ng g?1, delta-HCH = 1 to 10 ng L?1 and n.d. to 87 ng g?1, and aldrin = 1 to 7 ng L?1 and n.d. to 33 ng g?1 for filtered water and suspended matter samples, respectively. Heptachlor epoxide, dieldrin, o-p′ DDD, and p-p′ DDT were found to be present in solution at only one sampling site whereas p-p′ DDD and o-p′DDT were not detected. The analyses revealed a non-uniform distribution of these compounds over the studied area. The higher concentrations of organochlorines were detected downstream urban areas.  相似文献   

13.
The Hg concentrations in coal as fired in power plants in the Netherlands are low, 0.2 mg·kg?1 on average. After combustion the Hg is released partly (between 1 and 98%, on average 42%) in a gaseous phase, which is finally emitted into the air. The other part of the Hg, which remains in the ash is separated from the flue gases by electrostatic precipitators. The variation of the vaporisation percentage of Hg is probably caused by the presence of two chemical forms: Hgo and HgCl2. This may be concluded from the observation that relatively high concentrations of HCl in the flue gases (≈150 mg·m?3) give rise to low Hg concentration in the vapor phase. In cases when the concentrations of HCl are relatively low (≈25 mg·m?3) the amount of Hg in the vapor phase is high. The average gas phase concentrations of Hg in the flue gases, based on 33 measurements with no FGD, is 4.1 μg·mfo ?3. In a wet FGD based on the lime/limestone-gypsum process 50 to 70% of the Hg in the flue gases is removed, leaving a residual concentration of 1–2 μg·mfo ?3. The emission factor is then about 0.5 mg·GJ?1 or 5 μg·kWhr?1. In one particular measuring serie the fate of Hg was studied in a FGD-installation with a prescrubber.  相似文献   

14.
Observations on gaseous and particulate pollutants were undertaken at four locations in the region of a thermal power plant (TPP), which is under construction at Tuticorin, south India. The predicted concentrations Of SO2 due to the emissions from the TPP and its possible impact on the inhabitants and climate in the downwind region were evaluated. Also, the predicted concentrations downwind of a Petrochemical Industrial Complex (PIC) located in the vicinity of the TPP were computed and compared with the measured concentrations. The predicted maximum concentration of SO2 at 6 km downwind of TPP is about 530 μg m?3 under most favourable wind conditions. The anticipated increase in SO2 due to the thermal power plant under construction may therefore be substantial. The predicted concentrations Of SO2, at a distance of 1.8 km downwind of the PIC, varied between 34 and 216 μg m?3 for wind directions ranging from 70 to 90° and for Pasquill stability category C. The plume would be over the observational site when the wind direction is 80°. The maximum measured concentration was 23 ug m?3. The discrepancy was due to the rapid fluctuations in the wind direction during the observational period over a wide range from 20 to 90°.  相似文献   

15.
Acidic lakes and streams can be restored with base application (usually limestone) provided that the base does not wash out before the benefits of alkalization can be realized; liming soils of the adjoining watershed may be an alternative approach. This study was conducted to provide a scientific basis for soil liming. Plots (50 m2) with different limestone dosages (e.g. 0, 5, 10 or 15 Mg CaCO3 ha?1) were established on each of two different soils (a Spodosol and a Histosol) in the Woods Lake watershed of the Adirondack Park Region of New York, USA. Six months after soil liming much of the added limestone was still present in both the Spodosol and in the Histosol. Ten months after soil liming results indicated that: (1) soil pH increased (>1 unit) but mostly in the top 1 cm; (2) net N mineralization increased from 9.6 to ca. 15 µg N g?1 d?1 and nitrification increased from 2.8 to ca. 8 µg N g?1 d?1; (3) denitrification was not affected (98 µg N g?1 d?1); (4) CO2 production potential decreased in the surface soil and as a function of limestone dosage (60 to 6 µmol g?1 d?1); and (5) soluble SO 4 2? concentrations in the Histosol were not affected (105 µmol L?1). Liming acidic forest soils with >5 Mg CaCO3 ha?1 may increase the soil's acid neutralizing capacity, which could provide long-term benefits for surface water acidification.  相似文献   

16.
Nitrogen dioxide gas was rapidly absorbed by soil. After a 15 min incubation at 25°C, soil at a moisture content of 16% absorbed 99% of the NO2 introduced into the gas-phase volume of a closed system. The presence of microorganisms hatl no influence on the rate of absorption of the gas by soil. The absorption of NO2 by sandy clay loam soil was not an oxygen- or temperature-dependent process nor did it depend upon the moisture content of the soil. These physical factors acquired significance only in determining the initial rate of absorption of the gas and the rate at which NO2 diffused through the soil. Exposure of soil to NO2 resulted in substantial increases in the levels of NO inf2 sup? N in the soil. Chemical oxidation of the NO inf2 sup? N resulted in an increase in NO inf3 sup? N levels. During a 14-day incubation, NO inf2 sup? N concentrations in sterile soil exposed to an atmosphere containing 100 μg ml?1 of NO2 decreased from 190 μg g?1 of soil to 105 μg g?1 with an accompanying increase in NO inf3 sup? N from 2 μg g? 1 to 63 μg g?1 of soil. Nitrogen dioxide severely inhibited the growth of both aerobic and anaerobic asymbiotic N2-fixing bacteria in soil. After a 48 h incubation at 25°C, soil aggregates exposed to an atmosphere containing 100 μg ml?1 of NO2 contained 88% and 98% fewer aerobic and anaerobic N2-fixing bacteria, respectively. C2H2-reduction measurements showed that nitrogenase synthesis and activity in artificial soil aggregates amended with 2% glucose were inhibited by 20% and 48%, respectively, when exposed to atmospheric concentrations of 35 and 3.5 μg ml?1 of NO2, respectively.  相似文献   

17.
Barley (Hordeum vulgare L.) was grown on a sandy soil given different doses of cadmium carbonate (salt), copper carbonate (malachite), lead carbonate (cerussite), and zinc carbonate (smithsonite) in a pot experiment conducted in a greenhouse. The element compounds were added to the soil in amounts equivalent to the following levels of the metals: Cd 5, 10, 50 μq ?1; Cu and Pb 50, 100, 500 μg g?1; Zn 150, 300, 1500 μg g?1. Sequential extraction was used for partition these metals into five operationally-defined fractions: exchangeable, bound to carbonates, bound to Fe-Mn oxides, bound to organic matter and residual. The residue was the most abundant fraction in the untreated soil for all the metals studied (43 to 61% of the total contents). The concentration of exchangeable Cd (0.2 μg g?1), Cu (0.01 μg g?1), Pb (0.1 μg g?1), and Zn (1.4 μg g?1) were relatively low in the untreated soil but increased markedly in the treated soils for Cd (up to 31 μg g?1) and Zn (up to 83 μg g?1), whereas only small changes were observed for Cu and Pb. The pot experiment showed a significant increase in the Cd and Zn contents of barley grown on the treated soils, but only small changes in Cu and Pb concentrations.  相似文献   

18.
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   

19.
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   

20.
Marked differences exist between the S and Pb concentration in Cladina ranziferina collected from eastern Canada and the Northwest Territories, Canada. These differences reflected the differing emission/deposition rates in the two regions. The spatial distribution of S and Pb in the lichen from eastern Canada is described in detail. Mean S concentrations ranged from 329 to 959 μg g?l; Pb concentrations varied in the range 3 to 21 μg g?l. A regional gradient in lichen S concentrations was evident with the highest concentrations being found in central and north-central Ontario and the lowest in Newfoundland. A regional gradient for Pb was apparent but was not as well defined as that for S. The regional distribution of S illustrated by the lichen agreed with another indirect measurement of S deposition. Lichen S concentrations correlated with measured wet sulphate deposition.  相似文献   

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