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71.
234U and 238U activity concentrations and their relative effective doses have been determined in 10 bottled mineral waters in Tunisia. Alpha spectrometry was used as technique to measure uranium isotopes. The obtained isotopic ratio 234U/238U varies between 1.1 and 3 which means that the two isotopes are not in radioactive equilibrium. Measured activity concentration varies between 3.2 and 40 mBq/l for 234U and between 1.5 and 26.3 mBq/l for 238U. Effective doses (assuming 2 litres per day of water consumption) coming from this two isotopes are found to vary between 0.16 and 2.02 μSv/a which is lower than the maximum recommended dose level by the WHO.  相似文献   
72.
简要介绍了江苏苏源环保工程有限公司开发的OI^2-WFGD-Ⅱ湿法烟气脱硫技术的工艺特点、设备布置、技术参数、设备国产化以及技术应用。  相似文献   
73.
U.S. EPA Region IX is supporting bioassessment programs in Arizona, California, Hawaii and Nevada using biocriteria program and Regional Environmental Monitoring and Assessment Program (R-EMAP) resources. These programs are designed to improve the state, tribal and regional ability to determine the status of water quality. Biocriteria program funds were used to coordinate with Arizona, California and Hawaii which resulted in these states establishing reference conditions and in developing biological indices. U.S. EPA Region IX has initiated R-EMAP projects in California and Nevada. These U.S. EPA Region IX sponsored programs have provided an opportunity to interact with the States and provide them with technical and management support. In Arizona, several projects are being conducted to develop the State's bioassessment program. These include the development of a rotational random monitoring program; a regional reference approach for macroinvertebrate bioassessments; ecoregion approach to testing and adoption of an alternate regional classification system; and development of warm-water and cold-water indices of biological integrity. The indices are projected to be used in the Arizona Department of Environmental Quality (ADEQ) 2000 water quality assessment report. In California, an Index of Biological Integrity (IBI) has been developed for the Russian River Watershed using resources from U.S. EPA's Non-point Source (NPS) Program grants. A regional IBI is under development for certain water bodies in the San Diego Regional Water Quality Control Board. Resources from the U.S. EPA Biocriteria program are being used to support the California Aquatic Bioassessment Workgroup (CABW) in conjunction with the California Department of Fish & Game (CDFG), and to support the Hawaii Department of Health (DoH) Bioassessment Program to refine biological metrics. In Nevada, R-EMAP resources are being used to create a baseline of aquatic information for the Humboldt River watershed. U.S. EPA Region IX is presently working with the Nevada Division of Environmental Protection (NDEP) to establish a Nevada Aquatic Bioassessment Workgroup. Future R-EMAP studies will occur in the Calleguas Creek watershed in Southern California, and in the Muddy and Virgin River watersheds in southern Nevada, and the Walker River watershed in eastern California and west-central Nevada.  相似文献   
74.
Protection of the environment is critically dependent on the quality of data used in decision making. Whether the decisions are part of the scientific process or relate to application of the laws governing people and their living conditions, good quality data are required/needed by two disciplines with distinct differences. This paper examines some differences between science and the law, provides a brief history of science in law, discusses the effects of law on science, compares United States Environmental Protection Agency (U.S. EPA) guidance and U.S. Supreme Court credible science criteria. This paper further speculates on the future use of science data by the courts.  相似文献   
75.
Impact of water quality parameters on the sorption of U(VI) onto hematite   总被引:2,自引:0,他引:2  
In this study, the sorption of U(VI) from aqueous solution on hematite was studied as a function of various water quality parameters such as contact time, pH, ionic strength, soil humic acid (HA) or fulvic acid (FA), solid content and temperature by using a batch technique. The results demonstrated that the sorption of U(VI) was strongly dependent on ionic strength at pH < 6.0, and outer-sphere surface complexation may be the main sorption mechanism. The sorption was independent of ionic strength at pH > 6.0 and the sorption was mainly dominated by inner-sphere surface complexation. The presence of HA/FA increases U(VI) sorption at low pH, whereas decreases U(VI) sorption at high pH. The thermodynamic parameters (ΔH0, ΔS0, and ΔG0) were calculated from the temperature dependent sorption isotherms, and the results suggested that U(VI) sorption was a spontaneous and endothermic process. The results might be important for the application of hematite in U(VI) pollution management.  相似文献   
76.
The concentration of naturally occurring radionuclides 232Th, 238U was determined using Instrumental Neutron Activation Analysis (INAA) in different food groups namely cereals, vegetables, leafy vegetables, roots and tubers cultivated and consumed by tribal population residing around the proposed uranium mine. The study area is a part of rural area K. P. Mawthabah (Domiasiat) in the west Khasi Hills District of Meghalaya, India located in the tropical region of high rainfall that remains steeped in tribal tradition without much outside influence. Agriculture by Jhum (slash and burn) cultivation and animal husbandry are the main occupation of the tribal populations. A total of 89 samples from locally grown food products were analyzed. The concentration of 238U and 232Th in the soil of the study area was found to vary 1.6-15.5 and 2.0-5.0 times respectively to the average mean value observed in India. The estimated daily dietary intake of 238U and 232Th were 2.0 μg d−1 (25 mBq d−1) and 3.4 μg d−1 (14 mBq d−1) is comparable with reported range 0.5-5.0 μg d−1 and 0.15-3.5 μg d−1 respectively for the Asian population.  相似文献   
77.
Samples from a marine sediment core from the Irish Sea (54.416 N, 3.563 W) were analyzed for the isotopic composition of uranium, plutonium and americium by a combination of radiometric methods and AMS. The radiochemical procedure consisted of a Pu separation step by anion exchange, subsequent U separation by extraction chromatography using UTEVA® and finally Am separation with TRU® Resin.Additionally to radiometric determination of these isotopes by alpha spectrometry, the separated samples were also used for the determination of 236U/238U and plutonium isotope ratios by Accelerator Mass Spectrometry (AMS) at the VERA facility.  相似文献   
78.
本文对近年文献报导中水、食品和人体中的~(234)U和~(238)U含量,比活度比值的调查结果,并估算出了人体所受的内照射剂量,作了评述,引用文献19篇,表格14张.  相似文献   
79.
Previous research on territoriality suggests that territorial intrusion is associated with particular territorial demarcations. In the present study the use of territorial displays involving symbolic barriers, actual barriers, detectability, traces and social climate is related to the territorial intrusion of residential burglary. The five classes of territorial displays were assessed for a total of 306 burglarized houses on burglarized blocks, non-burglarized houses on burglarized blocks, and non-burglarized houses on non-burglarized blocks. After the data were reduced through factor analysis, multiple regression analysis revealed that burglarized houses differed from non-burglarized houses on non-burglarized blocks on four of the five classes of territorial displays. In general, burglarized houses had salient public territorial qualities: cues of openness and unoccupied appearance. In contrast, the non-burglarized houses had salient secondary or primary territorial qualities: territorial markers communicating privacy and individuality. In addition, non-burglarized houses had greater visual contact with neighboring houses.  相似文献   
80.
International EIA activity has two origins. First, there is increasing concern over conflict between developmental and environmental interests within the economic development system. Second, EIA appeals to international agencies and governments as a well-defined, internally integrated procedure and planning tool. EIA activities involve political, institutional, and technical motivations and goals for the international bodies and the governments of countries receiving aid. Three criteria may be used to evaluate international EIA from the perspective of policy makers and administrators in the countries: political support, institutional strengthening, and technical capability. This paper reviews the influence of the United Nations system and of some multilateral and bilateral development assistance agencies in promoting EIA in developing countries. The extent the nature of the influence donors have on EIA in developing countries is shaped as much by the interests and organizational characteristics of the donors as by the needs and priorities of the recipients.  相似文献   
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