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1.
Measurement of the rate and direction of ground water flow beneath Wollaston Beach, Quincy, Massachusetts by use of a heat-pulsing flowmeter shows a mean velocity in the bulk sediment of 40 cm d–1. The estimated total discharge of ground water into Quincy Bay during October 1990 was 1324–2177 m3 d–1, a relatively low ground water discharge rate. The tides have only a moderate effect on the rate and direction of this flow. Other important controls on the rate and volume of ground water flow are the limited thickness, geographic extent, and permeability of the aquifer. Comparisons of published streamflow data and estimates of ground water discharge indicate that ground water makes up between 7.4–12.1% of the gaged freshwater input into Quincy Bay. The data from this study suggest the ground water discharge is a less important recharge component to Quincy Bay than predicted by National Urban Runoff Program (NURP) models.The high nitrate and low nitrite and ammonia concentrations in the ground water at the backshore well sites and low nitrate and high nitrite and ammonia concentrations in the water flowing from the foreshore suggests that denitrification is active in the sediments. The low ground water flow rates and low nitrate concentrations in the foreshore samples suggest that little or no nitrate is surviving the denitrification process to affect the planktonic community. Similarly, oxidizing conditions in the aquifer and low trace metal concentrations in the ground water samples suggest that the metals may be precipitating and binding to sedimentary phases before impacting the bay.  相似文献   

2.
为提高四川省城市放射性废物库的安全管理水平,确保库区辐射环境安全和库内放射源实体安全,对2016—2021年四川省城市放射性废物库的库区环境监测结果进行了分析。分析表明:库区的γ辐射剂量率满足《核技术利用放射性废物贮存库选址、设计与建造技术要求》(试行)的要求,库区表面污染水平满足《电离辐射防护与辐射源安全基本标准》(GB 18871—2002)的规定,库区气溶胶历年监测数据一致性较好。此外,库区完善的安防措施为库区的安全运行提供了有力保障。四川省城市放射性废物库的运行未对库区环境造成不良影响,库区辐射环境质量良好。废物库的运行状态良好,库区辐射安全可控,其安全运行对保障全省核技术利用产业的发展和辐射环境的安全起到了重要作用。  相似文献   

3.
Pollution of the aquatic environment is a global concern owing to the devastating effects of contaminants whose levels are growing at an alarming rate, and it has become a major threat for marine organisms, as well as to humans as consumers. This study has been carried out on leaping mullet obtained from Aliaga Bay, which is located on the west coast of the Aegean Sea near Izmir and hosts the world’s fifth largest shipyard, plus a broad range of industrial activities, including an oil refinery and a paper factory. The waste from these industries, combined with municipal sewer discharges, is the main cause of pollution in this region. There is no national documentation or research on the determination of pollution resulting from the industrial activities in this area. In the present study, the degree of induction of CYP4501A-associated 7-ethoxyresorufin O-deethylase (EROD) activity and immunochemical detection of CYP1A1 in the liver of leaping mullet (Lisa saliens) were used as biomarkers for the assessment of polycyclic aromatic hydrocarbon (PAH)-type organic pollutants in Aliaga Bay. Mullet caught from different locations of the bay had approximately 52 times more EROD activity than the feral fish sampled from a clean reference site near Foca, Izmir. The results of this study indicate that Aliaga Bay is highly contaminated with PAH-type organic pollutants.  相似文献   

4.
A procedure is given for evaluating the toxic threat of selenium to fish and wildlife. Toxic threat is expressed as hazard, and is based on the potential for food-chain bioaccumulation and reproductive impairment in fish and aquatic birds, which are the most sensitive biological responses for estimating ecosystem-level impacts of selenium contamination. Five degrees of hazard are possible depending on the expected environmental concentrations of selenium, exposure of fish and aquatic birds to toxic concentrations, and resultant potential for reproductive impairment. The degree of hazard is given a numerical score: 5 = high hazard, 4 = moderate hazard, 3 = low hazard, 2 = minimal hazard, and 1 = no identifiable hazard. A separate hazard score is given to each of five ecosystem components; water, sediments, benthic macroinvertebrates, fish eggs, and aquatic bird eggs. A final hazard characterization is determined by adding individual scores and comparing the total to the following evaluation criteria: 5 = no hazard, 6–8 = minimal hazard, 9–11 = low hazard, 12–15 = moderate hazard, 16–25 = high hazard. An example is given to illustrate how the procedure is applied to selenium data from a typical contaminant monitoring program.  相似文献   

5.
The levels of 144Ce, 137Cs, 125Sb, and 90Sr in the open waters of the Great Lakes were measured over the period 1973–81. The levels were found to be very low. 144Ce was detected only up to 1975 after which it dropped below the detection limit. The data indicate that the concentrations of the remaining three radionuclides have decreased with time. 90Sr and 137Cs provide essentially all of the radiological dose from drinking Great Lakes water. The dose equivalant commitments have been calculated from these measurements and found to be well within the Great Lakes Water Quality Agreement's water quality objective for radioactivity.  相似文献   

6.
The purpose of this studywas to determine status and long-term trends of dissolved oxygen concentrations (DO) in Corpus Christi Bay, Texas, U.S.A. A 20-year record of randomized stations was used to determine the trend of surface water DO, salinity, and temperature over space and time. A 13-year record of two fixed stations was used to determine the temporal nutrient trends. A 10-year record of fixed stations in the southeastern region of Corpus Christi Bay was used to determine the status of disturbance caused by low DO in bottom waters. From 1982 to 2002, there was a significant decrease in surface water DO at a rate of 0.06 mg L−1 yr−1 and a significant increase in surface water temperature at a rate of 0.07°C yr−1. The southeastern region of Corpus Christi Bay had the lowest average DO, and during July and August, DO are steadily declining at a rate of 0.09 mg L−1 yr−1. It is not likely that eutrophication is causing hypoxia, because freshwater inflow rates have significantly decreased since 1941 and nutrient levels have not changed from 1987 to 2000. Even though long-term trends indicate that average surface DO is decreasing, disturbance by hypoxia appears to be stable, but this may be due to just eight years of data. In fact, if the current trend continues, surface water DO will not meet exceptional aquatic life standards (≤5 mgL−1) in 2032.  相似文献   

7.
The physico-chemical characteristics of the drinking water in nine residential halls of the Aligarh Muslim University, Aligarh, U.P. (India), were studied. Nine samples each of running and standing water were taken four times over a period of one month at weekly intervals from all of the residential halls and were analysed for physico-chemical characteristics and heavy metal contents. The temperature, pH and electrical conductivity of water samples ranged between 20.0–26.0°C; 7.00–8.00 and 116.00–199.04 micromhos cm–1 respectively whereas the values of total alkalinity, total hardness, Cl, SO 4 , F, NH3–N, NO2–N; NO3–N were found between 261.00–396.00; 128.00–200.00; 8.00–69.00; 12.00–46.00; 0.90–1.35; 0.20–0.44; ND; 1.60–6.50 mg l–1 respectively. The ranges of heavy metal concentrations in the running water samples were as follows: Cd (0.70–3.75); Cr (ND-5.00); Co (9.50–18.75); Cu (0.75–15.00); Fe (ND-13.50); Mn (3.50–51.00); Ni (7.00–17.50); Pb (0.50–2.50) and Zn (10.00–176.50) g l–1. The heavy metal concentrations in standing water samples were found to be: Cd (1.20–4.90); Cr (ND-10.00); Co (10.25–19.00); Cu (1.75–20.00); Fe (ND-18.00); Mn (5.00–66.50); Ni (8.75–19.75); Pb (0.75–5.50) and Zn (28.60–364.00) g l–1. The concentrations of heavy metals in drinking water supplies of the Aligarh Muslim University campus were well below the guidelines for drinking water quality as prescribed by World Health Organisation (1984). It is evident from the results that the drinking water may not cause any significant health hazard to water consumers due to heavy metals but these may be hazardous if they get accumulated in the body due to continuous consumption of water.  相似文献   

8.
Solvent extraction is recommended as a suitable method for the removal of heavy metals from the waste waters of the chemical and electronic industries. Common extractants are organic compounds with molecular mass 200–450, almost insoluble in water (5–50 ppm), that selectively extract metals from aqueous solutions. On the basis of data from the literature, the extraction conditions are reviewed for the metals that cause problems in waste waters. The extraction conditions are understood to mean the type of extractant, anion present in the aqueous phase, and pH. As far as the data permit, the metals are ordered according to their extractability by given extractants. Special attention is paid to the main source of contamination of waste waters by heavy metals, namely electroplating plants. Two examples of the design of mixer-settler batteries are presented, which demonstrate continuous removal of heavy metals from the waste waters of electroplating plants to levels below the permissible limits. The first example illustrates removal of cadmium using triisooctylamine in a mixer-settler battery with the pertraction flow-arrangement; the second, removal of zinc and lead from rinse waters using the organophosphoric acid DEHPA (bis (2-ethylhexyl) phosphoric acid) in a battery with counter-current flow and reflux. The extraction equilibrium data were obtained in laboratory experiments using chloride solutions in concentrations close to those in the rinse waters of electroplating plants (erná and Volaufová, 1991).  相似文献   

9.
Hazardous waste sites may pose a threat to human health and the environment when toxic substances are released. However, the contaminants present at a waste site may have originated on-site (i.e., resulting from releases attributable to site activities) or off-site (i.e., resulting from sources not on-site). Off-site substances may result either from natural sources (e.g., erosion of naturally occurring mineral deposits) or anthropogenic sources (e.g., widespread contamination from automobile exhaust in urban areas). To determine the appropriate action to take at a hazardous waste site, the U.S. Environmental Protection Agency (EPA) must distinguish between substances directly attributable to the hazardous waste site (i.e., site contaminants) and those attributable to natural background concentrations. The most important factor to consider when determining background concentrations is to ensure that the physical, chemical, and biological aspects of the media to be sampled at both the contaminated site and the background site are as similar as possible. Inorganics, in particular metals, are addressed. Radionuclides are not specifically addressed; however, metals with radioactive isotopes that may be encountered at hazardous waste sites are included. There are references and data included in this paper that provide average concentrations and reference values for selected soils and sediments in the United States. Suggested sampling and monitoring design approaches that could be used by scientists and engineers faced with how to determine background concentrations are identified. The issues discussed include the selection of background sampling locations, considerations in the selection of sampling procedures, and statistical analyses for determining whether contaminant levels are significantly different on a potential waste site compared with a background site.  相似文献   

10.
In contrast to the monitoring and prevention of occupational radiation risk caused by enhanced natural radioactivity, relatively little attention has been paid to the environmental impact associated with residues containing enhanced activity concentration of naturally occurring radionuclides. Such materials are often deposited directly into the environment, a practice which is strictly forbidden in the management of other types of radioactive waste. In view of the new trends in radiation protection, the need to consider the occurrence of anthropogenically enhanced natural radioactivity as a particular unique case of environmental hazard is quite apparent. Residues containing high activity concentrations of some natural radionuclides differ from radioactive materials arising from the nuclear industry. In addition, the radiation risk is usually combined with the risk caused by other pollutants. As such and to date, there are no precise regulations regarding this matter and moreover, the non-nuclear industry is often not aware of potential environmental problems caused by natural radioactivity. This article discusses aspects of environmental radiation risks caused by anthropogenically enhanced natural radioactivity stored at unauthorised sites. Difficulties and inconclusiveness in the application of recommendations and models for radiation risk assessment are explored. General terms such as “environmental effects” and the basic parameters necessary to carry out consistent and comparable Environmental Risk Assessment (ERA) have been developed and defined.  相似文献   

11.
Accumulation of Cu and Cd by Vallisneria spiralis was studied under laboratory conditions. Plants showed ability to reduce 5 µg ml–1 Cu background concentration to below 0.05 µg ml–1 (m.p.l., WHO 1985) within 48 h. The Cd concentration of 1.0 µg ml–1 was reduced to below m.p.l. (0.005 µg ml–1) in 168 h. Cysteine synthesis was more under Cd stress condition. Both the metals were toxic to the plants at higher concentrations; more in the case of Cd.NBRI Rsearch Publication No. 417 (N.S.).  相似文献   

12.
Lead,cadmium, arsenic and zinc in the ecosystem surrounding a lead smelter   总被引:2,自引:0,他引:2  
A lead smelter has been operating at Belledune in the province of New Brunswick, in eastern Canada, since 1966. This paper presents data on the concentrations of the four primary metals emitted from the smelter — lead, cadmium, arsenic and zinc — which were measured in the terrestrial environment near the smelter and the concentrate transport route. Deposition of these metals to the snowpack and the uptake by grass forage are discussed in relation to non-regulatory guidelines, toxicity and atmospheric emissions. A 1992 snowpack transect survey extending 0.5–40 km northwest, southeast and south of the smelter revealed lead concentrations of 2–3193 ppb, cadmium <0.10–49.7 ppb, arsenic <3.0–72.0 ppb, and zinc 3–401 ppb. Deposition estimates within this zone for lead were between 0.046 and 20.1 kg/ha/yr, cadmium <0.007 and 313 g/ha/yr, arsenic <0.016 and 453 g/ha/yr and zinc 0.020 and 2.52 kg/ha/yr. Concentrations of these metals in the snowpack were highest within 3 km of the smelter and were detectable at greater distances SE of the smelter. Lead was dispersed greater distances from the smelter than cadmium or arsenic. Snowpack samples collected within 5–20 m of the railway contained 140–7270 ppb of lead, 0.4–36.9 ppb of cadmium, <3.0–72.0 ppb of arsenic and 41–13100 ppb of zinc. Grass forage sampled within 0.6–16 km of the smelter contained lead 5–152 ppm, cadmium 0.10–4.1 ppm, and zinc 22–154 ppm. Highest concentrations of lead, cadmium and zinc in grass forage were found were found within 2.2 km of the smelter. Grass forage collected within 10–70 m of the railway contained lead 13–288 ppm, cadmium 0.4–1.3 ppm and zinc 98–831 ppm.  相似文献   

13.
Present and future annual methane flux estimates out of landfills, rice paddies and natural wetlands, as well as the sorption capacity of aerobic soils for atmospheric methane, are assessed. The controlling factors and uncertainties with regard to soil methanogenesis and methanotrophy are also briefly discussed.The actual methane emission rate out of landfills is estimated at about 40 Tg yr–1. Changes in waste generation, waste disposal and landfill management could have important consequences on future methane emissions from waste dumps. If all mitigating options can be achieved towards the year 2015, the CH4 emission rate could be reduced to 13 Tg yr–1. Otherwise, the emission rate from landfills could increase to 63 Tg yr–1 by the year 2025. Methane emission from rice paddies is estimated at 60 Tg yr–1. The predicted increase of rice production between the years 1990 and 2025 could cause an increase of the CH4 emission rate to 78 Tg yr–1 by the year 2025. When mitigating options are taken, the emission rate could be limited to 56 Tg yr–1. The methane emission rate from natural wetlands is about 110 Tg yr–1. Because changes in the expanse of natural wetland area are difficult to assess, it is assumed that methane emission from natural wetlands would remain constant during the next 100 years. Because of uncertainties with regard to large potential soil sink areas (e.g. savanna, tundra and desert), the global sorption capacity of aerobic soils for atmospheric methane is not completely clear. The actual estimate is 30 Tg yr–1.In general, the net contribution of soils and landfills to atmospheric methane is estimated at 180 Tg yr–1 (210 Tg yr–1 emission, 30 Tg yr–1 sorption). This is 36% of the global annual methane flux (500 Tg yr–1).  相似文献   

14.
Biotransformation processes play an active role in reducing the environmental impact of fuel hydrocarbon releases to groundwater. Because monitoring data at release locations are typically sparse, spatial variations in geochemical indicator parameters are often called upon as indirect evidence of biotransformation. These parameters include concentrations of electron acceptors (O2, NO3 -, SO> 4 2- , reduced redox reaction by-products (Fe2+, Mn2+, CH4), as well as bicarbonate alkalinity, pH and Eh. However, background variability in a number of these parameters complicates the task of data interpretation, particularly in the case of small data sets. In this study, correlation analyses are applied to geochemical indicator data at six hydrocarbon groundwater contamination sites in California to identify which parameters are the most reliable indicators. The results of the analyses suggest that the most direct indicators of the local redox environment – Fe2+, Mn2+, CH4, Eh – yield the most consistent evidence of hydrocarbon biotransformation. Indicators which rely largely on mass balance – O2, NO 3 - , SO 4 2- , alkalinity – appear to be less reliable. These findings may provide guidance in both the collection and interpretation of groundwater monitoring data at hydrocarbon contamination sites.  相似文献   

15.
Static bioassay were carried out using two aquatic crocodiles (the short nosed crocodile, Osteolemus tetraspis and the Nile crocodile, Crocodilus niloticus) as test organisms in soft natural dilution water, with Petroleum waste drilling fluid as the test material, at 28 ± 2 °C. Comparison of results for the control and different concentrations of the waste drilling fluid were made by means of the F-statistic method. Both crocodile species exhibited a high insensitivity to the undiluted waste drilling fluid and the different dilutions. Differences in concentration of waste drilling fluid did not influence the response of crocodiles to the potential toxicant. Percentage of deaths which was never greater than 0.2% in control tanks was not significantly different from that in test tanks where mortality values of organisms was typically 1.6% or less in most cases. There was a delay toxicant – induced mortality effect.  相似文献   

16.
Biodegradation tests were conducted on solidified waste forms containing ion exchange resins contaminated with high levels of radioactive nuclides. These tests were part of a program to test waste forms in accordance with the U.S. NRC Branch Technical Position on Waste Forms. Small waste forms were manufactured using two different solidification agents, Portland Type I–II cement and vinyl ester-styrene (VES). Ion exchange material was taken from a filter system which had been used to remove radionuclides from highly contaminated water. As specified by NRC, the waste forms were evaluated for their resistance to biological degradation using the G21 and G22 procedures of the American Society for Testing Materials (ASTM). Results showed that microbial growth can be supported by the VES waste forms. The particular organisms used in the tests did not grow in the presence of the cement waste forms. It is also shown that the ASTM tests specified in the Technical Position are not suitable for the use intended. A different testing methodology is recommended which would provide direct verification of waste form integrity.Work supported by the U.S. Nuclear Regulatory Commission, Office of Nuclear Regulatory Research, under DOE Contract No. DE-AC07-761D01570.This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, or any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for any third party's use, or the results of such use, of any information, apparatus, product or process disclosed in this report, or represents that its use by such third party would not infringe privately owned rights. The views expressed in this report are not necessarily those of the U.S. Nuclear Regulatory Commission.  相似文献   

17.
A survey of the concentrations of heavy metals — cadmium, zinc and total mercury — in the tissues of fifteen fish species from Samborombón Bay, La Plata river estuary, in Argentina, has been carried out. Liver appeared to be the main organ accumulating cadmium and zinc, while both liver and muscle showed a similar ability for accumulating mercury. The bioaccumulation process was verified for the three metals analyzed, even though low concentrations have been determined. The biomagnification process of the metals studied was not verified in this environment. The highest metal concentrations were recorded in Mugil liza, and particulate matter and sediments — which are closely related to its trophic and ecological habits — seemed to be the main source of metals for this species. Both Micropogonias furnieri and Mugil liza were recognized as possible indicator species for future monitoring programmes for heavy metals in Samborombón Bay. Considering the present results, this area of La Plata river estuary is characterized as a non-polluted environment.Scientific Researcher from the National Council for Scientific and Technological Researches (CONICET), of Argentina  相似文献   

18.
The activity concentrations of natural radionuclides in soils from the area affected by uranium mining at Stara Planina Mountain in Serbia were studied and compared with the results obtained from an area with no mining activities (background area). In the affected area, the activity concentrations ranged from 1.75 to 19.2 mg kg?1 for uranium and from 1.57 to 26.9 mg kg?1 for thorium which is several-fold higher than those in the background area. The Th/U, K/U, and K/Th activity ratios were also determined and compared with data from similar studies worldwide. External gamma dose rate in the air due to uranium, thorium, and potassium at 1 m above ground level in the area affected by uranium mining was found to be 91.3 nGy h?1, i.e., about two-fold higher than that in background area. The results of this preliminary study indicate the importance of radiological evaluation of the area and implementation of remedial measures in order to prevent further dispersion of radionuclides in the environment.  相似文献   

19.
Distribution of heavy metals in plants and fish of the Yamuna river (India)   总被引:2,自引:0,他引:2  
The distribution of cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb) and zinc (Zn) in the plants and fish of Yamuna river from Delhi to Allahabad, a distance of about 840 km, at five sampling stations was determined in the year 1981. The results have shown wide variations in the heavy metal levels from one sampling station to the other. The concentrations of Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn in the plants (Eicchornia crassipes) were found to be 0.02–0.12, 2.7–21.3, 4.6–64.8, 9.8–114.0, 193.0–1835.0, 380.0–1443.0, 4.4–83.0, 4.8–30.2, and 22.1–356.5 g g-1 respectively whereas in the fish (Heteropnuestes fossilis) were found to be ND-0.40, 2.3–13.7, 3.7–26.9, 8.33–58.1, 278.3–1108.0, 81.3–213.8, 2.8–32.7, 1.4–12.8 and 101.8–364.8 gg-1 respectively on dry weight basis.  相似文献   

20.
The potential ecotoxicity of fluorescent dyes used in tracing, and their possible effects on human health, were evaluated by reviewing available toxicological information for 12 dyes — fluorescein, Lissamine Flavine FF, Rhodamine WT, Rhodamine B, Sulpho Rhodamine G, Sulpho Rhodamine B, eosin, pyranine, Phorwite BBH Pure, Tinopal 5BM GX, Tinopal CBS-X, and Diphenyl Brilliant Flavine 7GFF — and a dye-intermediate, amino G acid. This evaluation used available toxicological information, test data on analogous substances, and mathematical expressions for biological activity. Based on set criteria for human health and acute ecotoxicity, the evaluation indicated that these tracers have low to moderate levels of concern. The use of these tracers for the study of groundwater flow is appropriate if consideration is given to the overall human health and environmental effects. Their use in the environment requires tracer concentrations not exceeding 1–2 mg 1–1 persisting for a period in excess of 24 h in the groundwater at the point of groundwater withdrawal or discharge. A simple calculated potential dose was used in a comparison of the estimated acute toxicity of Rhodamine WT in rats to the known acute oral toxic dose in humans for several known acutely toxic chemicals. This comparison showed that none of the fluorescent dyes evaluated would present an acutely toxic threat at or substantially above the recommended 2 mg 1–1 concentration.The U.S. Governments right to retain a non-exclusive, royalty free licence in and to any copyright is acknowledged. Disclaimer: The views of this paper are solely those of the authors and do not necessarily reflect the views or policies of the U.S. Environmental Protection Agency.  相似文献   

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