Application of in-situ measurement to determine Cs in the Swiss Alps

Establishment of ¹³⁷Cs inventories is often used to gain information on soil stability. The latter is crucial in mountain systems, where ecosystem stability is tightly connected to soil stability. In-situ measurements of ¹³⁷Cs in steep alpine environments are scarce. Most studies have been carried out in arable lands and with Germanium (Ge) detectors. Sodium Iodide (NaI) detector system is an inexpensive and easy to handle field instrument, but its validity on steep alpine environments has not been tested yet. In this study, a comparison of laboratory measurements with GeLi detector and in-situ measurements with NaI detector of ¹³⁷Cs gamma soil radiation has been done in an alpine catchment with high ¹³⁷Cs concentration (Urseren Valley, Switzerland). The aim of this study was to calibrate the in-situ NaI detector system for application on steep alpine slopes. Replicate samples from an altitudinal transect through the Urseren Valley, measured in the laboratory with a GeLi detector, showed a large variability in ¹³⁷Cs activities at a meter scale. This small-scale heterogeneity determined with the GeLi detector is smoothed out by uncollimated in-situ measurements with the NaI detector, which provides integrated estimates of ¹³⁷Cs within the field of view (3.1 m²) of each measurement. There was no dependency of ¹³⁷Cs on pH, clay content and carbon content, but a close relationship was determined between measured ¹³⁷Cs activities and soil moisture. Thus, in-situ data must be corrected for soil moisture. Close correlation (R² = 0.86, p < 0.0001) was found for ¹³⁷Cs activities (in Bq kg⁻¹) estimated with in-situ (NaI detector) and laboratory (GeLi detector) methods. We thus concluded that the NaI detector system is a suitable tool for in-situ measurements in alpine environments. This paper describes the calibration of the NaI detector system for field application under elevated ¹³⁷Cs activities originating from Chernobyl fallout.     

In vivo and in vitro metabolism of tobacco-specific nitrosamine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), by the freshwater planarian, Dugesia japonica

Cigarette smoke is a risk factor for human health, and many studies were conducted to investigate its adverse effects on humans and other mammals. However, since large amounts of cigarette products are produced and consumed, it is possible that tobacco chemicals can end up in aquatic environments through several routes, thus influencing aquatic organisms. In this study, the presence of tobacco-specific nitrosamine (TSNA), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), in aquatic environment was demonstrated. Since toxic effects on and distribution patterns of tobacco chemicals in aquatic organisms were rarely studied, after results of an acute toxicity pretest were obtained, experiment was conducted to investigate the bioaccumulation pattern of NNK and distribution patterns of its metabolites, mainly 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), in NNK-treated freshwater planarians, Dugesia japonica. Results from in vivo and in vitro studies showed that NNK was readily converted to NNAL through the carbonyl reduction in bodies of NNK-treated planarians. Tissue concentrations of both chemicals increased in time- and dose-dependent manners. Furthermore, we examined the end products of NNK/NNAL α-hydroxylation in NNK-treated planarians, but only 1-(3-pyridyl)-1,4-butanediol was detected, suggesting that NNK metabolism in planarians partially differs from that in mammalian systems. This is the first report on NNK metabolism in an aquatic organism and can be used as a foundation for developing freshwater planarians as a new in vivo model for the study of NNK toxicology in the future.     

拉萨高原环境点型感烟探测器工程参数调整研究

气压对燃烧过程影响显著,常压环境下的火灾探测器标准不适用于高原环境.以高原环境下的点型感烟火灾探测器为研究对象,根据合肥及拉萨两地的国标探测器正庚烷标准火测试对比试验,研究高原环境对火灾烟气及点型离子、光电感烟探测器响应规律的影响.结果表明,对于相同火源,光电感烟探测器在高原环境下的响应明显弱于常压环境,而离子感烟感测器所受影响相对较小.依据试验结果,提出高原环境下点型感烟探测器的工程参数调整建议.     

新型组合式消防服热防护性能分析

本文对不同隔热层材料组成的消防服的热防护性能进行了实验测试与分析验证,评价了新型组合式消防服和传统组合式消防服的隔热性能优劣。结果表明以SiO2气凝胶材料为隔热层的新型组合式消防服的导热系数约为传统型的1/4,具有更显著的热防护效果。     

主压缩沉降阶段垃圾填埋体渗透特性研究

针对垃圾填埋体的研究主要集中在降解及垃圾渗滤液处理,而其渗透特性研究不足的现状,选取处于4种压力状况下的垃圾填埋体,对其主压缩沉降阶段渗透特性进行室内物理试验,结合试验数据对垃圾填埋体渗透性能变化规律进行分析研究.结果表明,4种压力状况下垃圾填埋体试验测定分析符合达西定律,其COD变化处于产酸阶段,对渗透性能的影响可以不予考虑;在此基础上,对垃圾渗透系数计算表明,处于主压缩沉降阶段内,除没有施加压力状况下垃圾填埋体渗透性能变化规律与其他试验表现不尽相同外,其他垃圾填埋体渗透系数变化大致符合自然指数规律,而4种压力状态下的垃圾填埋体渗透系数数值均在10~(-4.5)～10~(-5.3) m·s~(-1)的范围内,与典型垃圾渗透系数的代表值相一致.     

突发性大气环境污染事故的应急监测

介绍了突发性环境污染事故的分类及特征，检测管法在突发性大气环境污染事故应急监测中的应用，并讨论了突发性环境监测中的个人防护问题。     

生活污水电导率与CODcr的相关性分析

CODcr标准测定方法测定时间较长,氯离子干扰较大.通过对生活污水电导率的测定,归纳出电导率与CODcr的相关性,在基层环境监测中较适用.     

陕西渭北旱塬区农田土壤有机质空间预测方法

准确预测土壤有机质(SOM)含量的空间分布对于改善土壤质量、提高区域土壤管理水平具有重要意义.为探索预测陕西渭北旱塬区农田SOM含量的最优模型,借助地理探测器选取与SOM含量密切相关的影响因子作为建模的协变量,选用普通克里格方法(OK)、地理加权回归模型(GWR)、偏最小二乘回归模型(PLS)、地理加权回归扩展模型(G...     

基于EBK插值预测和GDM模型的襄州区耕地土壤重金属时空分布及来源变化分析

为探讨襄州区重金属空间格局时空变化及其来源变化,于2009年11月和2019年11月分别在襄州区耕地土壤采集395个和326个土壤样品,测得两年铬（Cr）、铅（Pb）、砷（As）、汞（Hg）和镉（Cd）含量,采用经验贝叶斯克里金法（EBK）得出两年5种土壤重金属含量空间格局情况及变化量分布情况,并利用地理探测器模型（GDM）计算19种环境因子和5种重金属含量q解释力并比较两年变化情况.结果表明,与2009年相比,2019年襄州区Cr、Pb、Hg和As这4种土壤重金属含量整体趋于降低,Cd整体含量增加;2019年襄州区土壤重金属含量空间分异情况较2009年趋于复杂,Pb、Hg和Cd在南部、Hg在中部市区及周边地区也表现为含量增加;各元素向北及西北部地区表现为含量降低.2019年自然因子和污染企业距离对5种土壤重金属含量单因子解释力均有所下降,且单因子主控下对其含量的影响力显著性降低,而人类活动因子尤其是居民点用地距离、道路距离、污染企业用地和环境因子对土壤重金属元素的叠加影响力增强.说明2019年土壤重金属来源变化由以结构性因素为主要影响因素趋于复杂,污染企业的排放对重金属元素影响力降低,而人类活动对重金属含量影响增加.     

黔桂喀斯特区域河流水体离子对底栖硅藻群落的影响

为了建立喀斯特地区河流底栖硅藻对水环境变化的响应模型,定量研究了中国西南喀斯特地区黔桂珠江水系典型岩溶水体中的离子、电导率与底栖硅藻群落分布的关系.研究发现,电导率的范围为20-2070 μS·cm-1,并且ca2+与(HCO-3+CO2-/3)是岩溶水体的主要优势离子.对离子、电导率与硅藻群落结构进行主成分分析(PCA)、对应分析(CA)、加权平均分析(WA)和相关性分析,结果表明,水体离子(HCO-3+CO2-/3、SO2-/4、NO3-、Cl-、Ca2+、Na+、Mg2+、K+)与电导率环境变量都能用于解释底栖硅藻的群落分布特征;而ca2+、(HCO3-+CO2-/3)和Na+浓度是影响物种组成的显著因素.通过研究确定了以上8种水体离子和电导率的相应指示种值(最适值Optima),以及这些离子环境下的硅藻分布特征.该结果为中国西南喀斯特地区硅藻种群生态学、个体生态学以及水质评价的研究提供了理论依据.