乌鲁木齐市水体中天然放射性水平初探

本文报道了乌鲁木齐市水体中天然放射性水平的初步调查结果.天然放射性核素含量属正常本底水平,从辐射卫生安全角度来看,人对水的利用是安全的.     

Mapping radioactivity in groundwater to identify elevated exposure in remote and rural communities

A survey of radioactivity in groundwater (110 sites) was conducted as a precursor to providing a baseline of radiation exposure in rural and remote communities in Queensland, Australia, that may be impacted upon by exposure pathways associated with the supply, treatment, use and wastewater treatment of the resource. Radionuclides in groundwater, including ²³⁸U, ²²⁶Ra, ²²²Rn, ²²⁸Ra, ²²⁴Ra and ⁴⁰K were measured and found to contain activity concentration levels of up to 0.71 BqL⁻¹, 0.96 BqL⁻¹, 108 BqL⁻¹, 2.8 BqL⁻¹, 0.11 BqL⁻¹ and 0.19 BqL⁻¹ respectively. Activity concentration results were classified by aquifer lithology, showing correlation between increased radium isotope concentration and basic volcanic host rock. The groundwater survey and mapping results were further assessed using an investigation assessment tool to identify seven remote or rural communities that may require additional radiation dose assessment beyond that attributed to ingestion of potable water.     

Microbial degradation op tripluralin by aspergillus carneus,fusarium oxysporum and trichoderma viride ∗

Abstract

³H‐Trifluralin was synthesized by condensation of ³H‐4‐chloro‐3,5‐dinitro‐α, α, α‐trifluorotoluene with di‐n‐propylamine.

After incubation of trifluralin with Aspergillus carneus, Fusarium oxysporum and Trichoderma viride for 10 days, a small percentage (less than 10%) of unchanged herbicide was recovered in the extractable fraction. This indicates a fairly rapid degradation of the herbicide by the fungal species. Other than trifluralin, the culture medium contained at least five labelled products: 2, 6‐dinitro‐N‐n‐propyl‐α, α, α‐tri‐fluoro‐p‐toluidine; 2, 6‐dinitro‐α, α, α‐trifluoro‐p‐toluidine; 2‐amino‐6‐nitro‐α, α,‐trifluoro‐p‐toluidine, 2, 6‐dinitro‐4‐trifluoromethyl phenol and a major polar product which constituted more than 50% of the total extractable transformation products. A pathway, which similates that of aerobic degradation of the herbicide in soil, is suggested for the microbiological degradation of trifluralin.     

Assessment of the radiological impact of oil refining industry

The field of radiation protection and corresponding national and international regulations has evolved to ensure safety in the use of radioactive materials. Oil and gas production processing operations have been known to cause naturally occurring radioactive materials (NORMs) to accumulate at elevated concentrations as by-product waste streams. A comprehensive radiological study on the oil refining industry in Egypt was carried out to assess the radiological impact of this industry on the workers. Scales, sludge, water and crude oil samples were collected at each stage of the refining process. The activity concentration of ²²⁶Ra, ²³²Th and ⁴⁰K were determined using high-resolution gamma spectrometry. The average activity concentrations of the determined isotopes are lower than the IAEA exempt activity levels for NORM isotopes. Different exposure scenarios were studied. The average annual effective dose for workers due to direct exposure to gamma radiation and dust inhalation found to be 0.6 μSv and 3.2 mSv, respectively. Based on the ALARA principle, the results indicate that special care must be taken during cleaning operations in order to reduce the personnel's exposure due to maintenance as well as to avoid contamination of the environment.     

Animal Burrowing Attributes Affecting Hazardous Waste Management

/ Animal burrowing is critical to the formation of soils and contributes to the interface between geological materials and organic life. It also influences the management of hazardous materials at nuclear waste facilities and elsewhere. For example, residues and waste products from the production of nuclear weapons are released onto the ground surface and within engineered burial structures. Soil bioturbation has exposed radionuclides and other hazardous materials to wind and rain, thereby risking inhalation and injury to humans and wildlife on and off site. Soil bioturbation can expand soil depths and spatial distributions of the source term of hazardous waste, potentially increasing chronic exposures to wildlife and humans over the long term. Ample evidence indicates that some of the large quantities of hazardous materials around the world have been released from soil repositories, where they have also contaminated and harmed biota. Key burrowing parameters influencing these outcomes include the catalog of resident species, and their abundance, typical burrow volumes (void space created by soil displacement), burrow depth profiles, maximum depth of excavation, constituents and structural qualities of excavated soil mounds, and proportion of the ground covered by excavated soil. Other important parameters include rate of mound construction, depth of den chambers, and volume of burrow backfill. Soil bioturbation compromised the integrity of some hazardous waste management systems using soil, but the environmental impact remains largely unknown. Designers and operators of waste management facilities, as well as risk assessors, need to understand how burrowing animals influence hazardous waste storage.KEY WORDS: Burrowing; Environmental impact; Radioactivity; Risk; Soil bioturbation; Hazardous waste     

居室放射性测量与防护探讨

研究家庭装饰建材的放射性辐射及其防护问题，经过多种材料的放射笥水平测量分析，给出其分布规律，介绍了家庭装修建材放射性安全防护方法。     

建筑材料放射性的控制

通过对建筑材料放射性污染状况分析，指出建筑材料放射性与其生产原料来源直接相关；并与其生产工艺及建筑物高度和结构有关。     

上海市水体中人工放射性水平调查及评价

调查了１９８９－１９９１年不海市各类水体中人工放射性核素的水平。调查共设点１５个，采集枯、丰水期水样４５个，结果表明，上海市各类水体中＾９０Ｓｒ、＾１３７Ｃｓ和总β放射性浓度均低于国家生活饮用水卫生限制标准，属正常本底水平。按调查结果估算的上海市居民从饮水中摄入的人工放射性核素＾９０Ｓｒ、＾１３７Ｃｓ、＾３Ｈ，所致人均年有效剂量为３．８×１０＾－７ＳＶ，与全国均值相吻合。     

锦州地区食品和水中放射性水平及居民内照射剂量研究

对锦州地区20种食品,2种饮用水、温泉水和海水中总α、总β、¹³⁴U、²³⁸Ｕ、²³²Th²²⁶Ra、⁹⁰Sr、¹³⁷Cs含量进行了测量。估算了该地区居民对6种放射性核素的年摄入量和有效剂量当量。研究结果表明：居民总年摄入量,城市居民为417.8Bq,a^-1,农村居民为12.57×102Bq·a^-1;居民总有效剂量当量,城市和农村居民分别为26.5和37.9μSv,这与居民膳食组成有关。此外,讨论了各类食品或放射性核素对总剂量的相对贡献份额。     

论燃煤过程中的放射性污染

国内煤层中普遍存在的天然放射性核素，通过燃煤产生的烟气、煤灰渣等介质进入空气、土壤和水环境中。公众健康危害评价结果证明燃煤排放的放射性污染物通过吸入途径对人体的总危害危险大于二氧化硫、氨氧化物等一般污染物。鉴于我国近几年火电厂等煤炭消耗量大，并且不断增长的现状，指出对燃煤造成的放射性环境污染应予足够的重视。