Assessment of the natural radioactivity in the soils of Windhoek city, Namibia, Southern Africa

The radioactivity concentrations of (238)U, (232)Th and (40)K in 160 soil samples collected from 16 geographical areas across Windhoek city, Namibia, have been determined using an HPGe detector and found to vary from 15.0 +/- 1.3 to 37.8 +/- 2.1 Bq kg(-1) for (238)U, 17.5 +/- 2.7 to 62.1 +/- 3.3 Bq kg(-1) for (232)Th and 168.9 +/- 15.0 to 784.9 +/- 30.1 Bq kg(-1) for (40)K. These concentrations were used to calculate the mean absorbed dose rate and the mean annual effective dose for the city. The value of 0.07 +/- 0.01 mSv y(-1) obtained for the mean effective dose is less than the maximum permissible dose of 1 mSv y(-1) recommended for the public by the International Commission on Radiological Protection.     

Radionuclide Enrichment Near Coal Processing in Southern Brazil

This work highlights environmental radionuclide enrichment as a result of coal mining activity, including disbursement related to the coal processing in southern Brazil. Soil cores collected near the coal mining area showed ²³⁸U, ²²⁶Ra and ²¹⁰Pb activities approximately 2 times greater than the background values. The highest activities were found at the surface and decrease downcore, indicating recent enrichment. Furthermore, atmospheric analyses of particulate matter indicated radionuclide enrichment up to 352 and 463 μBq m^–3 of ²²⁶Ra and ²¹⁰Pb, respectively, at the sites nearest to the coal-fired power plant. The atmospheric particulate material showed ²¹⁰Pb/²²⁶Ra ratios similar to the fly ash near the coal-fired power plant, suggesting an enhanced source of ²²²Rn to the atmosphere likely associated with the power plant. However, no risk to the population near the coal processing was found, as noted by the total air absorbed γ-ray dose rate in the topsoil samples, 74 ± 19 nGy h^–1, statistically similar to the background radioactivity (60 nGy h^–1).     

A scientometric assessment of the Southern Africa Development Community: science in the tip of Africa

This article reports the results of a scientometric assessment of the Southern Africa Development Community countries. The National Science Indicators database of Thomson-Reuters and the online ISI Web of Knowledge are utilized in order to identify the number of publications of the 15 countries over a period of 15 years; the activity and relative impact indicators of 22 scientific disciplines for each country and their collaborative patterns. It is identified that South Africa with 19% of the population in the region is responsible for 60% of the regional GDP and 79% of the regions publications. All countries tend to have the same focus in their disciplinary priorities and underemphasize disciplines such as engineering, materials science and molecular biology. It is expressed concern that the current research infrastructures are inadequate to assist in reaching the objectives developed in the Regional Indicative Strategic Development Plan of the Community.     

魏晋南北朝时期酒器设计的约制因素研究

目的 从影响魏晋南北朝时期酒器设计的约制因素角度,研究该时期酒器设计的独特性。方法 以典型案例的设计分析作为切入点,从人的约制、社会的约制、社会生产生活方式的约制、环境及技术的约制,4个视角逐一分析其对该时期酒器艺术所造成的影响。结论 魏晋南北朝时期的酒器设计是因当时特殊的时代背景下所产生的约制因素所影响造化的,提出在遵循约制规则前提下,现代酒器设计可借鉴以“折衷”方式传递“形、意、神”的设计方法,将该时期的酒器设计思想转移至现代酒器设计中。     

Assessing the sustainability of energy technological systems in Southern Africa: A review and way forward

The field of technology assessment is not new, but it continues to be relevant today more than ever, especially in the energy sector. Issues related to climate change, energy security and sustainability in general are at the core of all energy policies and strategies. The development of new and more sustainable energy technologies are needed to address these challenges. As part of this, energy technology assessment tools can help decision-makers with the identification of sustainable energy solutions, in order to integrate them in long-term energy policies and strategies. The concept and practice of sustainable development has subsequently manifested in the technology assessment field. This implies the re-classification of technology assessment into ecological, economic and social (and other) goals. In the Southern African context, specifically, there is no formal and coherent approach to energy technology assessment from a sustainability perspective. Governments in the region are finding it challenging to establish national policies concerning energy technology assessment. Indeed, the review reveals the limited use of the term “technology assessment” in energy evaluation studies in Southern Africa. Energy sustainability assessments may be reported, but certainly not from the perspectives of the technology management community, and, although a number of studies have discussed the issues of sustainability in technology assessment, none account for technology sustainability assessment from a holistic perspective. The paper argues that it is in this area that further research is needed.     

The biochemical response to different Cr and Cd concentrations in soils amended with organic wastes

The effects of adding municipal solid waste (MSW) or poultry manure (PM) on the biochemical properties of a soil polluted with Cr and Cd were studied. Soil was mixed with Cr(NO₃)₃ and Cd(NO₃)₂ to give three concentrations (0, 100, and 250 mg Cr kg⁻¹ and 0, 100, and 250 mg Cd kg⁻¹) in the soil, which was then treated with MSW at a rate of 10% or PM at a rate of 7.6%. The pH and biochemical parameters were measured at 0 and 120 days. An unamended and no-polluted soil was used as control. Compared with the non-polluted soil, for the 250 mg Cd kg⁻¹ treatment the microbial biomass-C, dehydrogenase, urease, β-glucosidase, phosphatase, and arylsulphatase activities decreases 23%, 26.2%, 36%, 34.8%, 18.4%, and 15.8%, respectively, whereas for 250 mg Cr kg⁻¹ treatment the biochemical parameters were slightly lowest than for 250 mg Cd kg⁻¹ treatment. For 250 mg Cr kg⁻¹ soil + 250 mg Cd kg⁻¹ soil treatment, the inhibition percentages of the biochemical parameters increased. After the application of organic wastes in Cr + Cd polluted soil, the inhibition of biochemical properties was greater with the MSW amendment than with PM, possibly due to its higher humic acid concentration.     

Different manifestations of ‘context’: examples from a bibliometric study of research in Zimbabwe in Southern Africa

Scientometrics - ‘Context’ refers to the environment in which a phenomenon exists or takes place, and which can help to understand the phenomenon. Aspects of context are present in all...     

魏晋南北朝高士图中坐具的莲花纹饰特征和意义研究

目的研究魏晋南北朝高士图中的坐具形制和纹饰特征,探析其历史成因、演进过程和符号意义。方法以南京西善桥考古出土的《竹林七贤与荣启期》砖画这一魏晋南北朝时期高士图的代表作品为例,依据历史文献、石窟艺术、佛教文化等相关背景资料,剖析《竹林七贤与荣启期》砖画中坐具的纹饰特征和意义,并结合与此画有密切关联的唐代孙位所绘的《高逸图》中的坐具纹饰特征进行佐证。结论南朝《竹林七贤与荣启期》高士图中的坐具具有明显的莲花纹饰特征,反映了当时人们对魏晋高士的文化尊崇和"坐莲升仙"的精神寄托。这与当时盛行的人物品藻、佛教文化等具有内在的密切关联,莲花纹饰自此也成为后世摹本高士图中坐具的重要装饰纹样。     

Bioslurry treatment for soils contaminated with very high concentrations of 2,4,6-trinitrophenylmethylnitramine (tetryl)

Past and current DoD activities have resulted in the contamination of soil, sediment and groundwater with various explosive compounds. This research was undertaken to determine the effectiveness of a soil bioslurry process for remediation of soil with very high concentrations of 2,4,6-trinitrophenylmethylnitramine (tetryl). A 99.9% reduction in tetryl concentrations (from 100,000 to below 100 mg/kg) was achieved in 180 to 200 days. A variety of process modifications (i.e. addition of fertilizer, microbial biomass, purging with nitrogen, etc.) that were performed during the course of the experiment did not increase the tetryl biodegradation rate beyond the rates of degradation without modifications. Subsequent batches of soil added as a 25% (v/v) replacement of the slurry were also degraded. These results indicate the potential for this process to remediate highly contaminated soils at many former and current ammunition manufacturing sites.     

伴生放射性矿中放射性核素检测实验室比对总结

The state has issued a series of measures to regulate the radiation of associated radioactive ores. For this reason, the Beijing Research Institute of Uranium Geology organized the activity of “BRIUG IC-2018 Interlaboratory Comparison of Radionuclides and Heavy Metals in Associated Radioactive Mines”. Our laboratory actively participated in 238U, 232Th, 226Ra, 40K comparing activities and studied measuring parameters, sample loading conditions and so on. Satisfactory results were obtained in the comparison activities.It shows that our laboratory has strong detection ability, which lays a solid foundation for similar radionuclide detection work in the future. Finally, some suggestions for future work improvement are put forward.     

Unified Counting Channels in State Standards for Radionuclide Activity,Neutron Flux,and Neutron Flux Density

There is a program for upgrading the measuring equipment forming part of the State Primary Standards for the units of radionuclide activity, neutron flux, and neutron flux density, where it is planned to replace fifteen counting channels by various types of standardized channel of four types. These unified channels are considered for two primary standard-equipments, and their technical and metrological advantages are emphasized. Metrological characteristics are given for equipment containing the unified channels, which are compared with nonunified ones.     

Indoor radon concentrations in Adana, Turkey

The indoor radon concentration in Adana, Turkey was measured in living rooms of 52 houses during winter 2005 and 57 houses during summer 2005. Forty-four houses were selected for both winter and summer researches for estimating seasonal variations. Indoor radon concentrations were measured seasonally over hotter and colder 2 months over the whole year, using CR-39 passive nuclear track radon detectors. The radon concentrations were ranged from 15 to 97 Bq m(-3) on January-February 2005 for 60 d and from 5 to 70 Bq m(-3) on June-July 2005 for 60 d. The average summer concentration measured was 25.8 Bq m(-3) and the average winter concentration was 48.9 Bq m(-3) in 44 houses that observed seasonal variations. The differences between winter and summer periods were ranged from 1 to 77 Bq m(-3). The average value in both winter and summer periods is 37 Bq m(-3) in 44 houses that observed seasonal variations. This value is below the worldwide indoor radon concentration distribution of 46 Bq m(-3). The annual effective dose equivalent from (222)Rn was 0.9 mSv y(-1).     

Radionuclide content and associated radiation hazards of building materials and by-products in Baoji, West China

Seven types of common building materials and by-products of coal-fired power plants collected from Baoji, West China, were analysed for the natural radioactivity of 226Ra, 232Th and 40K using gamma ray spectrometry with an NaI(Tl) detector. The average activity concentrations vary from 23.0 to 112.2, 20.2 to 147.5 and 113.2 to 890.8 Bq kg(-1) for 226Ra, 232Th and 40K, respectively. The measured activity concentrations for these radionuclides were compared with the data reported from other countries and with the worldwide average activity of soil. As a measure of radiation hazard to the people, the radium equivalent activities, total annual effective dose and activity concentration index were estimated. The radium equivalent activities of the studied samples are below the internationally accepted values. The calculated total annual effective dose and the activity concentration index of seven types of common building materials are <1 mSv y(-1) and 1, respectively. But fly ash and bottom ash exhibit the higher values that exceed and be close to the acceptable values, respectively. This study shows that the measured building materials do not pose any significant source of radiation hazard and are safe for use in the construction of dwellings. Nevertheless, when fly ash and bottom ash are used in dwelling construction, it is important to assess their radiation potential.     

Assessment of metals contamination of soils in Ulaanbaatar, Mongolia

The purpose of this survey is to investigate the current status of metal pollution of the soil in Ulaanbaatar, the capital city of Mongolia. During the last decade, the city has been rapidly urbanized. Twenty-two soil samples were collected from different parts of the city and analyzed by aqua regia extraction. Generally, metal pollution was not a serious problem in the city and there was no significant evidence of infiltration of metal solutions into subsoil (at a depth of 30 cm). However, it was recently found that the arsenic(As) concentration in the soil was higher than the guideline value and the lead(Pb) content in some samples was higher than normal. The source of As pollution appears to be the coal combustion in three power plants in the city. The sources of the increase in Pb pollution might be the remarkable increase in the number of used vehicles and the increase in the use of leaded fuel in the last few years. To evaluate the leaching potential of heavy metals, sequential extraction was conducted. The quantity of the easily extractable fraction of metals was lower than that of the hardly extractable (residual) fraction. As a result, the leaching potential of heavy metals in Ulaanbaatar was found to be quite low.     

Distribution of phthalate esters in urban soils of subtropical city, Guangzhou, China

Surface soils from 37 sampling sites including roadsides (RS), parks (PA) and residential areas (RE) of the Subtropical City, Guangzhou, were collected in December of 2005 and analyzed for 16 phthalate esters (PAEs). PAEs were detected in all surface soils analyzed, which indicate that PAEs are ubiquitous environmental contaminants. The summation operator(16)PAEs concentrations ranged from 1.67 to 322 microg g(-1)-dry weight (dw), with the median concentration of 17.7 microg g(-1)-dw, mainly originating from municipal solid waste leachate, discarded plastic effusion, municipal sewage and atmospheric depositions. Concentrations of PAEs were poorly correlated with soil organic carbon content, suggesting mixing process between local and on-going sources. Of the 16 PAEs, diisobutyl phthalate (DiBP), di-n-butyl phthalate (DnBP) and di(2-ethylhexyl) phthalate (DEHP) dominated the PAEs, with the median concentrations of 1.63 microg g(-1)-dw, 1.80 microg g(-1)-dw and 14.8 microg g(-1)-dw, respectively, and accounted for 74.2-99.8% of the summation operator(16)PAEs concentrations. Principal Component Analysis (PCA) was applied to the distribution patterns of PAEs in the urban soils. Significant correlations existed among DiBP, DnBP, and DEHP, and between dimethyl phthalate (DMP) and diethyl phthalate (DEP). No significant differences of PAE congeneric profiles were observed between this and studies conducted elsewhere, which is consistent with the application of similar commercial PAEs around the world. As compared to the results from other studies, the urban soils of Guangzhou city were severely contaminated with PAEs. The environmental and human health risks posed by PAEs in the urban soils of Guangzhou city may deserve further attention.     

The Role of Phytoplankton in Self-Purification of Water Bodies with Radionuclide Pollutants

Radiochemistry - The review considers the participation of phytoplankton in the self-purification of water bodies from radionuclide pollutants. An assessment of the mobility of the main...