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1.
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   

2.
Transport of contaminants from coal storage areas through the rooting zone has the potential to negatively affect shallow ground water and terrestrial vegetation. Reject coal piles represent a worst-case scenario for contamination from coal storage areas because of the long residence time of the coal. Preliminary hydrologic data were collected from an area of stressed vegetation adjacent to an inactive ash basin and reject coal pile in South Carolina. The water table is near the surface (< 60 cm) in this wetland area and water movement is primarily to the west, toward the Savannah River. Acid leachate migration from the reject coal pile has contaminated the water-table aquifer with sulfate (up to 22 200 mg L?1) and metals (Fe to 9560 mg L?1) Al to 1110 mg L?1) A shallow plume of contaminated ground water parallels the reject coal pile and is elongated in the direction of ground-water movement. The plume is migrating westward at a calculated velocity range of 6.3 to 10.4 m yr?1. Leachate migration from the reject coal has produced a highly acidic (pH down to 2.2) and highly saline (EC to 11.8 dS m?1) rooting zone and is most likely responsible for the stressed vegetation in the study area.  相似文献   

3.
In order to ensure adequate performance and warn of potential ground water contamination, land application systems must be monitored. The monitoring system for the Lake George Village Sewage Treatment Plant land application system is described, including suction lsyimeters, observation wells and tracer studies.  相似文献   

4.
The coastal dune aquifer, providing drinking water for a large part of the population of the western Netherlands, is recharged by fainfall and artificial infiltration of Rhine water. Chernobyl fall-out has been detected in both water sources. At the Castricum lysimeter station the rainfall-derived water, draining from 2.25 m of unsaturated sandy soil, shows levels of Cs-137 around the detection limit of 20 to 40 mBq kg?1. At this site, the soil itself retained some Chernobyl-derived Cs-137 in the top 10 cm, where a similar quantity of old Cs-137 has also been retained. Penetration of old Cs-137 is deeper (up to 70 cm) under oak vegetation than in the bare soil. In the infiltration channels, fed by Rhine water, the bottom mud contains only Chernobyl-derived Cs nuclides. Radioactivity from Cs-137 is about one tenth of that from natural radioactivity due to K-40. Cesium levels are apparently unrelated to adsorptive properties.  相似文献   

5.
Survival ofEscherichia coli was studied in water from the Great Salt Lake, a highly saline lake with an ionic composition much like sea water. Samples used were from the most concentrated north arm (343.1 g l?1 solids) and the less concentrated south arm (about 113 g l?1 solids). At temperatures from 20°C to 9°C the bacterial death rate (k) for the north arm was ?0.17 log day?1 and the south arm and 1:3 dilution ?0.28 log day?1. Above 9°C the rate of death increased approximately exponentially and at 19°C the rate of death increased approximately exponentially and at 19°C the death rate was ?1.31 log day?1 in the north arm and ?0.98 log day?1 in the lower salinity water. These rates fall within those reported for sea water and are much higher than fresh water. Possible causes of death are discussed with the most likely being the high concentrations of minor elements or osmotic stress. The survival characteristics ofE. coli in waters with a sea water-like composition should require the same health concern as sea water regardless of the actual concentration of salt. High salt water of other ionic composition may behave differently, however.  相似文献   

6.
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   

7.
Lake water and sediment samples from approximately 2200 lakes and glacial sediment (sub-solum) samples from about 1800 sites were collected throughout a 38000 km2 rectangular area extending from Georgian Bay east to the Ottawa and St. Lawrence Rivers, Ontario, Canada. Lake water alkalinity and pH patterns are similar to the distribution of carbonate components in glacial drift. Carbonate-rich drift derived from the Paleozoic limestone terrain on the northeast flank of the Precambrian Frontenac Arch has been dispersed in a southwestward direction across a variety of non-calcareous metasedimentary and igneous rocks of the Canadian Shield, providing a buffering capacity to lakes situated in granitic terrain. The distribution patterns of mobile trace and minor elements are influenced by geochemical processes associated with subaerial weathering, ground and surface water transport, and the geochemical environment within the lakes themselves. Although composition of the drift is generally reflected by lake geochemistry, these post depositional processes can cause significant variations between patterns derived from the two sample types. Anions and cations such as S04 , Cl?, Na+, and F? exhibit concentration patterns thought to reflect both anthropogenic inputs and natural variations due to differences in the geology. All regional geochemical patterns may show evidence of local enhancement caused by high concentrations of chemically distinctive minerals in drift or nearby bedrock.  相似文献   

8.
The feasibility of removing nitrates from otherwise potable water by means of anion exchange was investigated. Candidate anion exchange resins had to demonstrate a higher affinity for nitrate ions than for the other ions present (Cl?, HCO3 ?). The distribution factor between chloride and nitrate was investigated with the anion exchange resin Amberlite-400. In studies of column operation it was found that sea water was as effective as NaCl for regeneration. The nitrate ion capacity was proportional to the nitrate ion concentration and to the TDS in the feed. Nitrate ion leakage was greater with lower levels of regeneration. An operational capacity for nitrate of 0.3 to 0.4 me ml?1 was found; this capacity was not significantly affected by the presence of sulfate ion in low concentration (2 me 1?1).  相似文献   

9.
Comparisons of stream water chemistry over a 2 yr period in East Fork, which drains an entirely forested watershed, and Big Run, which drains a forested watershed 8 % of which is occupied by Big Run Bog, indicated that Big Run Bog had no effect on stream water H+ or Cl? concentrations, but with increasing stream discharge the wetland was a source of Ca++ Mg++, K+, Na+, NO3 ?, and SO4 ?, and a sink for Fe+ +. Further comparisons with Tub Run, which drains a forested watershed, 13 and 12% of which is occupied by Tub Run Bog and an abandoned, unreclaimed coal surface mine, respectively, suggested that Tub Run Bog removes H+, Ca ++, Mg++, Fe++, and 504 ? from inputs of acid mine drainage. Wetland areas on the landscape contribute to the regulation of stream water chemistry in ways that are different from upland areas, and wetlands may have considerable applied potential for minimizing the impact of the mine drainage on stream water quality.  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.
The influence of NTA, EDTA, STPP, Triton X100, PO inf4 sup3 and NO inf3 sup? on the mobilization of Pb, Cd, Cu, Cr and Mn from sediments of two rivers located in Northern Greece was studied. The release caused by all examined complexing agents was higher in deionized water than either Axios or Aliakmon river water due to the lack of competition of Ca and Mg cations with the heavy metals for the studied complexing agents, and the decrease of ionic strength. From all examined agents NTA and EDTA showed the greater mobilization ability. Copper showed the greater tendency for remobilization by all examined agents, (according to the order: EDTA?NTA, Triton X1004 PO inf4 sup3? > NO inf3 sup3? ?STPP) while Cr and Mn the smallest following the orders: NTA, PO inf4 sup3? >> NO inf3 sup? , Triton X1004 EDTA, STPP and STPP > EDTA > NTA > Triton X 100 ? PO inf4 sup3? NO3, respectively. An increase in mobilization was noticed with an increase of agent concentration and time of shaking.  相似文献   

12.
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   

13.
The occurrence and characteristics of chemically-based density stratification in portions of the Seneca and Oswego Rivers, downstream of ion-polluted Onondaga Lake, are described for seven different days in the summer and fall of 1978 and 1981, which covered a wide range of river flows. The results indicate that chemically-based density stratification occurs routinely in the Seneca River downstream of the lake inflow, in response to a continuous chemically-based density difference between the two systems of 0.0015 to 0.0030 g cm?3. The persistence of the phenomenon, and therefore the longitudinal range over which the river stratification occurred, was dependent on the velocity of river flow and the magnitude of the density gradient that bordered the upper river water and the lower released lake water. During the low flows common to summer the stratification extended approximately 14 km downstream to a dam, and 3 km upstream, of the lake outlet — river junction. Vertical mixing between the stratified layers increased as the flow in the Seneca River increased, and as the vertical density gradient decreased. A dimensionless group, $$\frac{D}{{V\left( {\frac{\rho }{{\Delta _\rho /\Delta _z }}} \right)}}$$ where: D = apparent vertical diffusion (m2 hr?1), V = average velocity of the overlying river flow (m hr?1 ), p = density at the interface between the stratified layers (g cm?3), and Ap/Az = density gradient between the stratified layers (g cm?3 m?1), was found to be constant for summer low flow conditions for a 6.5 km length of the Seneca River, thus quantifying the interaction between vertical mixing and the included influences for that portion of the river. The occurrence of chemical stratification in the river had dramatic implications on the corresponding distribution of dissolved oxygen (DO). The isolation of the organically enriched lake water in the lower layer enhanced the depletion of DO there, which resulted in the development of substantial (> 4.0 mg 1?1 ) DO stratification downstream of the discharge from the lake during summer low flow periods.  相似文献   

14.
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   

15.

Purpose

A multi-compartment monitoring study was performed to characterize the effect of environmental variables, such as temperature and water flow as well as sediment characteristics, on the distribution and transport of persistent organic pollutants (POPs) in a dynamic river system during 1 year in an industrial region in central Europe.

Materials and methods

Waterborne polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were assessed over a period of 1 year at five sampling sites in the Morava River in the Czech Republic. Contaminants were measured monthly in riverbed sediments, freshly deposited sediments, water samples and passive samplers.

Results and discussion

Sediments are the main carrier of POPs in the river. Distinguishable patterns of PAHs, OCPs and PCBs in sediment indicate that their origin is from distinct sources and different transport pathways. The PAHs were identified as the dominant contaminant group of compounds with a mean concentration in sediment of 5,900 μg kg?1. Such concentrations are up to 10 times higher than in the Danube River, into which Morava drains. In contrast, mean concentrations of PCBs, hexachlorocyclohexanes (HCHs), dichlorodiphenyltrichloroethane and its breakdown products (DDTs) and hexachlorobenzene (HCB) of 6.0, 0.4, 4.2 and 6.0 μg kg1, respectively, are similar to those in the Danube. With some exceptions, no significant difference in composition of surficial riverbed sediments and those collected using sediment traps was observed. Despite the presence of potential local pollutant sources, the differences in contaminant concentrations between sites in the region were in most cases not significant. Variations in POP concentrations in sediments are mainly induced by high flow events, whereas seasonal variability was not observed.

Conclusions

The changes in contaminant concentrations in Morava River sediments are induced by episodic high flow events that cause erosion of contaminant-containing particles and their deposition at suitable downstream sites.  相似文献   

16.
The growth rates of two diatoms, acidophilic Asterionella ralfsii and circumneutral A. formosa, were differentially affected by varying pH, Al, and EDTA in chemically defined media. Free Al ion concentration increased as pH and EDTA concentration decreased. Free trace metal ion concentration decreased as EDTA levels increased but increased by orders of magnitude upon addition of Al. pH had an overriding species specific effect on growth rate; at low pH A. ralfsii had higher growth rates than A. formosa and vice versa at high pH. For both species higher EDTA levels depressed growth rates. Moderate additions of Al generally resulted in growth stimulation. The growth rate stimulations, especially at 200 and 400 μg L?1 Al additions, correlate to increases in free trace metal ion concentrations. The EDTA-AI interaction effects on growth rate were both pH and concentration dependent: at pH 7 both species were stimulated by addition of Al at all EDTA levels (except A. ralfsii at 5.0 mM EDTA and A. formosa at 0.5 mNM EDTA); at pH 6 Al addition either stimulated or had no effect on the growth rates of both species (except at low EDTA and high Al levels); at pH 5 A. formosa did not grow and additions of 200 μg L?1 Al stimulated growth of A. ralfsii. It is likely that the effect of pH, Al, and EDTA on speciation of essential or toxic trace metals affects growth rates of these diatoms in a species specific manner.  相似文献   

17.

Purpose

Previous studies in the Mezquital Valley evidenced that irrigation with untreated sewage effluent supplies two- to tenfold larger nitrogen doses to crops than common fertilizer recommendations. However, nitrate concentrations in the groundwater are only slightly above threshold concentrations for drinking water. To understand the N dynamics in this agroecosystem, we quantified nitrogen inputs, outputs, and transformations within the rooting zone and in the vadose zone down to the aquifer (i.e., in the critical zone).

Materials and methods

Single irrigation events were monitored in three different fields cropped with either annual rye grass (Lolium rigidum) or oats (Avena sativa L.) harvested for fodder. For each irrigation event, the total amount of water entering and leaving the field was quantified with a flowmeter. Soil pore water was collected with either microsuction cups or observation wells and groundwater was sampled at two wells. All water samples were analyzed for total nitrogen (Nt), ammonium nitrogen (NH4 +–N), nitrate nitrogen (NO3 ?–N), chloride (Cl?1), and pH. Organic N was calculated as the difference between total N and inorganic N. The water tension and the soil water content were monitored before, during, and after the irrigation with tensiometers and TDR probes, respectively, installed at different depths and at three sites within each field. Batch experiments were conducted to assess the NH4 + adsorption capacity of the soils.

Results and discussion

The irrigations added 537 to 727 kg ha?1 N in form of organic N (40 %) and NH4 +–N (60 %) to the fields. Crops absorbed 65 % of the N and 31 to 66 kg NO3 ?–N ha?1 leached out beyond the rooting zone (>40 to 130 cm). Batch experiments evidenced an ammonium adsorption capacity of 43 and 53 % of the input ammonium mass. Nitrification dominated over denitrification as the water infiltrated through the soil, evidenced by changes in nitrate concentrations and pH values in the soil pore water. The behavior of the total N/Cl ratio with depth indicated possible N losses due to NH3 volatilization at the field surface, a temporal withdrawal of N from the soil solution due to NH4 +–N adsorption in the rooting zone, as well as probable denitrification losses in the vadose zone.

Conclusions

Although the studied agroecosystem muses the large N inputs relative efficiently, between 7 and 10 % of the added N with each irrigation leaches beyond the crop root zone as nitrate. This is triggered by overflow irrigation, since up to 8,699,000 L of water with N concentrations of up to 50 mg total N L?1 infiltrate rapidly through macropores beyond the rooting zone. Additionally, ammonia volatilization and denitrification seem to be occurring. The latter could provide a self-cleaning potential to the system, if it reaches N2 and needs further verification. Nevertheless, N inputs to the system should match crop uptake to avoid groundwater and atmospheric pollution.
  相似文献   

18.
After recalling briefly the optical properties of aerosols, we describe the principle and the working conditions of photoelectric apparatus for aerosol measurements. Two size distribution analyzers are presented: the first one is based on a classical detection principle, the minimum detectable radius being 0.2 µm, and the maximum concentration 3 × 104 particles cm?3; the second one is based on a photon counting technique, with which particles of radius between 0.03 and 0.2 µm can be measured at maximum number concentration of 2 × 106 particles cm?3. We describe then two Condensation Nuclei Counters (CNC) with continuous flux; in these types of apparatus, the vapor of a liquid is condensed on Aitken nuclei using a Peltier effect device. They are thereby rendered visible and counted using a classical photoelectric method. One apparatus works under normal conditions of pressure and temperature, while the other one works under stratospheric conditions, i.e., at low pressure and temperature. The concentration range is still between 10 and 106 nuclei cm?3 and the minimum concentration is 0.1 particle cm?3 in the case of the stratospheric counter. The four devices work on individual particles; their characteristics are compared to those of commercially available apparatus and their advantages discussed.  相似文献   

19.
Arbacia punctulata eggs were continuously exposed to various concentrations (0.5, 1, 5, 10 mg l?1) of the PCB mixture, Aroclor 1254 in filtered sea water using reagent grade acetone as a carrier molecule. Control eggs were cultured in acetone and sea water. The effects of the PCB on fertilization efficienty, pluteus development, and its acute toxicity to the eggs were studied. Differences between control and experimental results were tested using Chi-square and a 95% level of confidence. When the eggs were initially exposed to the PCB at the time of fertilization there were no significant differences between the % fertilization, pluteus development, or % mortality when the controls were compared to the experimentals. However, when the eggs were initially exposed to PCB 1 h prior to fertilization there was a reduction in fertilization efficiency in all PCB concentrations. In all but the 0.5 mg l?1 PCB concentration, the % mortality was higher and the % pluteus development was lower.  相似文献   

20.
A field program for the measurement of the physical and chemical properties of aerosols and clouds was conducted at Whiteface Mountain, N.Y., during an 8-week period in June, July, and August 1983. Analysis of two-stage Nuclepore filter samples by proton-induced X-ray emission (PIXE) spectroscopy showed that most (85 to 90%) of the aerosol sulfate was in the accumulation mode (modal radius r - 0.1 μm) and that ?90% of total sulfate originated southwest of the Whiteface Mountain site. During a typical pollution episode originating in the Midwest, the total aerosol sulfate concentration was 19 pg m ?3, or 63 of total dry aerosol, which was - 30 gg m? s. Scavenging of sulfate aerosol by clouds was found to be greater than 95% efficient in clouds of 0.5gm?3 liquid water content. Measured pH values when the air mass trajectories were from the southwest were systematically lower than when the trajectories were from the northwest or northeast, i.e., 3.4 vs 4.4 and 4.8. In the southwest sector water samples, S04 ?2 and N03 ? were highly correlated to each other and to free H+, Ca2 ?, Cl?, Pb, and Ba.  相似文献   

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