Radionuclides in marine mammals off the Portuguese coast

Radionuclide analyses were performed in tissue samples including muscle, gonad, liver, mammary gland, and bone of marine mammals stranded on the Portuguese west coast during January-July 2006. Tissues were collected from seven dolphins (Delphinus delphis and Stenella coeruleoalba) and one pilot whale (Globicephala sp.). Samples were analyzed for ²¹⁰Po and ²¹⁰Pb by alpha spectrometry and for ¹³⁷Cs and ⁴⁰K by gamma spectrometry. Po-210 concentrations in common dolphin’s muscle (D. delphis) averaged 56 ± 32 Bq kg⁻¹ wet weight (w.w.), while ²¹⁰Pb averaged 0.17 ± 0.07 Bq kg⁻¹ w.w., ¹³⁷Cs averaged 0.29 ± 0.28 Bq kg⁻¹ w.w., and ⁴⁰K 129 ± 48 Bq kg⁻¹ w.w. Absorbed radiation doses due to these radionuclides for the internal organs of common dolphins were computed and attained a 1.50 μGy h⁻¹ on a whole body basis. ²¹⁰Po was the main contributor to the weighted absorbed dose, accounting for 97% of the dose from internally accumulated radionuclides. These computed radiation doses in dolphins are compared to radiation doses from ²¹⁰Po and other radionuclides reported for human tissues. Due to the high ²¹⁰Po activity concentration in dolphins, the internal radiation dose in these marine mammals is about three orders of magnitude higher than in man.     

High background radiation investigated by gamma spectrometry of the soil in the southwestern region of Cameroon

The aim of this work is to determine the radioactivity concentration of ²²⁶Ra, ²³²Th and ⁴⁰K in sub-surface (0-5 cm) soil samples collected from Awanda, Bikoué, Ngombas in the southwestern region of Cameroon, to assess their contribution to the external dose exposure relative to the United Nation Scientific Committee on Effects of Atomic Radiation (UNSCEAR) data. An HPGe p-type detector coupled to a multichannel analyzer was used to perform measurements and data processing. The activity concentrations of ²²⁶Ra varied from 0.06 ± 0.01 to 0.27 ± 0.02 kBq kg⁻¹ with a mean value of 0.13 ± 0.01 kBq kg⁻¹ wet weight. The activity concentrations of ²³²Th varied from 0.10 ± 0.01 to 0.70 ± 0.05 kBq kg⁻¹ with a mean value of 0.39 ± 0.03 kBq kg⁻¹ wet weight, and ⁴⁰K concentrations varied from 0.37 ± 0.02 to 1.53 ± 0.11 kBq kg⁻¹ with a mean value of 0.85 ± 0.07 kBq kg⁻¹ wet weight, respectively. The mean value of outdoor annual effective doses were estimated to be 0.48 mSv y⁻¹, 0.39 mSv y⁻¹ and 0.38 mSv y⁻¹ from Ngombas, Awanda and Bikoué, respectively. The studied areas can be said to have a high background radiation level.     

环境中氡辐射水平及控制措施分析

近年来,随着社会经济的发展,居民生活不断提高,对居室进行美化装修既成一种时尚。然而由安装（选用劣质材料）而引发的居室辐射水平超标,特别是氡辐射超标问题,已越来越受到人们的关注。为使人们对辐射环境有一基本认识和了解,作者根据多年从事辐射环境监测的经验,对环境空气中氡的性质、来源、辐射水平、危害及室内氡浓度控制措施作一简单分析介绍。     

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。     

Radiocaesium Activity Concentrations in Wheat Grains in the Republic of Croatia for 1965–2003 and Dose Assessment

Results of systematic, long-term measurements of ¹³⁷Cs activities in wheat for the period 1965–2003 are summarized. Radiocaesum fallout activities affect wheat activity concentrations, the coefficient of correlation being 0.91. In the observed period, the highest activity of ¹³⁷Cs deposited by fallout, 6321 Bq m⁻², was recorded in 1986, i.e., in the year of Chernobyl accident, causing peak ¹³⁷Cs activity concentration in wheat of 38.0 ± 13.0 Bq kg⁻¹. After the Chernobyl nuclear accident the ¹³⁴Cs:¹³⁷Cs activity ratio in wheat was ≈0.5, and did not differ from the value found in other environmental samples. The transfer coefficient from ¹³⁷Cs fallout deposition to wheat was calculated to be 8.6 × 10⁻³ Bq y kg⁻¹ per Bq m⁻², indicating the low transfer of radiocaesium from fallout to wheat. The upper limit for the collective effective dose for the Croatian population due to ¹³⁷Cs and ¹³⁴Cs ingestion by wheat and wheat products consumption for period 1965–2003 was estimated to be 665 person-Sv, the upper limit for the annual collective effective dose in 2003 being only about 0.061 person-Sv.     

Use of Airborne γ-Ray Spectrometry for Environmental Assessment of the Rehabilitated Nabarlek Uranium Mine, Australia

This article describes an airborne γ survey of a 7 × 5 km region around the rehabilitated Nabarlek uranium mine in northern Australia. An unusually tight line spacing (100 m) and low aircraft height (50 m) were used, enabling the survey to distinguish man-made structures such as ponds and accommodation areas, as well as creek lines. Positive correlations between airborne data and ground-based readings enabled an estimation of the average absorbed dose rate arising from terrestrial γ radiation over large areas of the site to be derived. For the fenced minesite area this estimate was 0.31 μ Gy hr^{− 1}. The airborne survey data were found to be invaluable in helping to plan further ground-level investigations and showed promise as an assessment tool for rehabilitated minesites.     

SO2排放造成的森林损失计算:以湖南省为例

SO₂排放对我国的森林生态系统造成了严重的损害,因而损失计算对于SO₂控制具有重要意义,但是目前仍缺乏有效的方法计算不同排放水平下的森林损失.本研究以硫沉降超临界负荷作为计算森林损失的参数,推导了适用于我国硫沉降导致森林损失的剂量-响应函数,并以湖南省为例,以1995为基准年,计算了2000年～2020年高中低3种SO₂排放方案下的森林损失.研究结果表明,随着今后湖南省经济和能源消费的增长,森林损失将继续增加.高排放方案下2020年SO₂排放将增长1.2倍,但森林损失增长4.3倍,边际损失高于6000元/t.在当前排放水平下对SO₂排放进行削减,边际效益达到1500元/t,因此控制SO₂具有显著的经济效益.对湖南案例的不确定性分析显示,计算方法有较高的可靠性.研究结果为区域SO₂控制策略的优化提供了支持.     

Tools for an enhanced solvent properties screening in the early stages of pharmaceutical process development

The objective of this research was the implementation of tools for the evaluation of solvents trough property screening in the early stages of process development. An important feature of the tools is that the implementation of indexes, scores, or weights is avoided. Information already available from the literature was stored in a database in order to turn raw data into decision making information. As a result, a solvent radar chart, a solvent representation table, and a solvent telescopying tool were developed in an ASP.NET application. The synthesis of Propranolol was used as study case in order to explore the selection of solvents in the early stages of process development. The replacement of diethyl ether was possible in the extraction step, while solvent choices were detected for potential telescoping for extraction and crystallisation steps. Solubility was found as a critical parameter in telescoping analysis. The methodology proposed enhanced the view towards a more holistic perspective and a more robust solvent screening process. As a consequence, the next steps into solvent evaluation and process development can be reduced.     

Effects of carbaryl on the aminotransferases in the mid gut of blister beetle,Mylabris pustulata (Thunb)

The activity levels of aminotransferases such as alanine aminotransferases (AlAT), aspartate aminotransferases (AAT), isoleucine aminotranferases (IlAT), leucine aminotransferases (LAT), valine aminotrasferases (VAT) were measured in the mid gut of the blister beetle; Mylabris pustulata (Thunb) exposed to sublethal doses of carbaryl. The insecticide markedly inhibited the activity levels of all aminotransferases exposed for either short or prolonged treatments. The beetles regained normal enzymic activity after withdrawal from the treatment. It is possible that chronic exposures of beetles to carbaryl may induce impairment in protein synthesis in the mid gut of the beetle.     

土壤水分对稻田土壤有效砷及碱性磷酸酶活性影响

采用室内模拟方法,在35%、65%和110%最大饱和持水量（WHC）条件下,系统地分析了稻田土壤有效砷及碱性磷酸酶活性变化规律.结果表明：砷污染稻田土壤后有效砷含量随砷污染浓度增加而增大,随培养时间延长逐渐降低,15d后趋于稳定;淹水降低了土壤有效砷含量及碱性磷酸酶活性;采用U=A/（1+B×C）模型较好拟合了不同水分下土壤碱性磷酸酶活性（U）与砷浓度（C）关系,表明碱性磷酸酶活性在一定程度上可表征不同水分下稻田土壤砷污染程度;计算得到稻田土壤砷轻度污染临界浓度（ED₁₀）为总砷67mg/kg和有效砷11mg/kg.研究表明适当调控土壤水分含量是控制稻田土壤砷毒性的有效方法之一.