基于模式生物秀丽隐杆线虫的环境污染物生殖毒性研究进展

由于人类社会的发展,环境污染也越来越严重,研究环境污染物对生态及人类健康的影响极为重要。生殖系统是人和动物繁衍后代的重要系统,常见环境污染物对生殖系统的影响正引起研究人员的广泛关注。秀丽隐杆线虫具有身体透明、品系丰富和遗传背景清楚等优点,为生殖毒理学研究提供了一个便利的平台。以秀丽隐杆线虫为模型已对多种环境污染物的生殖毒性进行了评价。本文重点叙述了重金属、纳米材料、有机物等化学污染,辐射、磁场等物理污染,以及病毒等生物污染对秀丽线虫生殖系统的影响,并归纳讨论了环境污染物造成生殖功能障碍的几种主要机制,如氧化应激、DNA损伤、内质网应激以及神经损伤等,但不同类型污染物的毒性效应与其自身的物化性质紧密相关。环境污染物诱导的生殖毒性中不同响应机制之间的关联性、不同发育阶段的敏感性差异、污染物的传代效应以及有效的缓解方式的筛选等都有待进一步的开展。     

上海市郊销售使用农药的环境毒理评价

调查了上海市郊1994年的农药销售使用量,并对其进行了农药排毒系数和农药使用危险性的环境毒理评价。结果表明,1994年上海市郊农药总销售用量为2418.64t,总排毒系数为35.43×10~6t/a,销售使用农药的LD_(50)为68.3mg/kg,接近我国高毒农药LD_(50)的界限(50mg/kg)。农药总用量最高的是南汇县,最低的是宝山区;排毒系数最高的也是南汇县,最低的是崇明县和浦东新区。从环境毒理角度看,上海市郊销售使用农药的结构很不合理,存在高效农药比例小,农药急性毒性高,使用危险性程度较高,及水溶性农药比例较大等问题。     

亚硝酸根的光度测定法

根据国内外１０９篇文章，对测定环境样品亚硝酸根的分光光度法（重氮连反应及亚硝化反应）、荧光光度法、动力学光度法及计算光度法等１００多种分析方法进行了评述。     

水工隧洞岩溶涌水的水文法计算

在总结数个不同类型水工隧洞岩溶涌水实例的基础上,提出了采用水文参数计算水工隧洞岩溶涌水的新方法,即利用同地区岩溶管道水及中小河流实测得到的最大径流模数,或据常年日暴雨计算得到的径流模数,乘以不同的折减系数来计算隧洞岩溶涌水量。折减系数考虑了岩溶管道与水工隧洞的接触关系、岩溶管道水的补给及出流特征,并提出了相应的经验值。     

Statistical aspects of inhalation toxicokinetics

The statistical analysis of dynamic processes is a useful tool to learn how environmental and ecological systems work and how they respond to disturbances. In the context of human risk assessment of potentially harmful chemicals, many complex dynamic processes in terms of kinetics have to be taken into account. Thorough research of direct influence of chemicals to humans depends on investigations with animalsin vivo andin vitro. However, when animals serve as models of human systems, one critical step is the extrapolation from the risk observed in the experimental animals to the risk associated with the human organism. To extrapolate the observed risk in this case, the detailed knowledge of the relevant kinetic processes as well as their differences between species is fundamental. On the other hand experimental tools for these processes are quite restrictive. Based on simple experimental designs a statistical method is proposed for characterizing such kinetic processes using the well-known compartmental analysis tool and non-linear regression. The methodology is then exemplified by non-invasive toxicokinetic inhalation experiments with rats.     

除草剂阿特拉津的环境毒理研究进展

叙述了阿特拉津的应用概况及其在生产实践中所存在问题;阿特拉津在生物体内和环境中的降解代谢过程。综述了近年来国内外在阿特拉津的残留分析方法、环境毒理学和微生物降解等方面的研究进展。     

Developing a CFD heat transfer model for applying high expansion foam in an LNG spill

Liquefied natural gas (LNG) is widely used to cost-effectively store and transport natural gas. However, a spill of LNG can create a vapor cloud, which can potentially cause fire and explosion. High expansion (HEX) foam is recommended by the NFPA 11 to mitigate the vapor hazard and control LNG pool fire. In this study, the parameters that affect HEX foam performance were examined using lab-scale testing of foam temperature profile and computational fluid dynamics (CFD) modeling of heat transfer in vapor channels. A heat transfer model using ANSYS Fluent® was developed to estimate the minimum HEX foam height that allows the vapors from LNG spillage to disperse rapidly. We also performed a sensitivity analysis on the effect of the vaporization rate, the diameter of the vapor channel, and the heat transfer coefficient on the required minimum height of the HEX foam. It can be observed that at least 1.2 m of HEX foam in height are needed to achieve risk mitigation in a typical situation. The simulation results can be used not only for understanding the heat transfer mechanisms when applying HEX foam but also for suggesting to the LNG facility operator how much HEX foam they need for effective risk mitigation under different conditions.     

LES – DFSD modelling of vented hydrogen explosions in a small-scale combustion chamber

Accidental explosions are a plausible danger to the chemical process industries. In the event of a gas explosion, any obstacles placed within the path of the flame generate turbulence, which accelerates the transient flame and raises explosion overpressure, posing a safety hazard. This paper presents numerical studies using an in-house computational fluid dynamics (CFD) model for lean premixed hydrogen/air flame propagations with an equivalence ratio of 0.7. A laboratory-scale combustion chamber is used with repeated solid obstacles. The transient compressible large eddy simulation (LES) modelling technique combined with a dynamic flame surface density (DFSD) combustion model is used to carry out the numerical simulations in three-dimensional space. The study presented uses eight different baffle configurations with two solid obstructions, which have area blockage ratios of 0.24 and 0.5. The flame speed, maximum rate of pressure-rise as well as peak overpressure magnitude and timing are presented and discussed. Numerical results are validated against available published experimental data. It is concluded that, increasing the solid obstacle area blockage ratio and the number of consecutive baffles results in a raised maximum rate of pressure rise, higher peak explosion overpressure and faster flame propagation. Future model development would require more experimental data, probably in a more congested configuration.     

A study of the blast wave shape from elongated VCEs

Elongated congestion patterns are common at chemical processing and petroleum refining facilities due to the arrangement of processing units. The accidental vapor cloud explosion (VCE) which occurred at the Buncefield, UK facility involved an elongated congested volume formed by the trees and undergrowth along the site boundary. Although elongated congested volumes are common, there have been few evaluations reported for the blast loads produced by elongated VCEs. Standard VCE blast load prediction techniques do not directly consider the impact of this congested volume geometry versus a more compact geometry.This paper discusses an evaluation performed to characterize the blast loads from elongated VCEs and to identify some significant differences in the resulting blast wave shape versus those predicted by well-known VCE blast load methodologies (e.g., BST and TNO MEM). The standard blast curves are based on an assumption that the portion of the flammable gas cloud participating in the VCE is hemispherical and located at grade level. The results of this evaluation showed that the blast wave shape for an elongated VCE in the near-field along the long-axis direction is similar to that for an acoustic wave generated in hemispherical VCEs with a low flame speed. Like an acoustic wave, an elongated VCE blast wave has a very quick transition from the positive phase peak pressure to the negative phase peak pressure, relative to the positive phase duration. The magnitude of the applied negative pressure on a building face depends strongly on the transition time between the positive and negative phase peak pressures, and this applied negative phase can be important to structural response under certain conditions. The main purpose of this evaluation was to extend previous work in order to investigate how an elongated VCE geometry impacts the resultant blast wave shape in the near-field. The influence of the normalized flame travel distance and the flame speed on the blast wave shape was examined. Deflagration and deflagration-to-detonation transition regimes were also identified for unconfined elongated VCEs as a function of the normalized flame travel distance and flame speed attained at a specified flame travel distance.     

The utility of behavioral studies for aquatic toxicology testing: A meta-analysis

Behavioral responses have been applied for decades as tools for aquatic toxicity testing, but have received far less attention than studies assessing lethality, development or reproduction. With improved visual and non-visual assessment tools and increased knowledge of the importance of behavior for organism health and fitness, interest in behavioral analysis has increased in recent years. However, to our knowledge there has never been a quantitative assessment of the available techniques for organismal toxicity testing, so it is not clear whether behavioral studies represent valuable additions to environmental monitoring. We performed a meta-analysis comparing the relative sensitivities and average durations of behavioral studies to those assessing acute lethality, development and reproduction. Results demonstrate that the average duration of behavioral studies is consistently less than developmental or reproductive studies, and that behavioral endpoints are generally more sensitive than those assessing development or reproduction. We found effect sizes to be lower but power to be higher in behavioral and reproductive studies compared to studies assessing development, which likely relates to low sample sizes commonly used in developmental studies. Overall, we conclude that behavioral studies are comparatively fast and sensitive, and therefore warrant further attention as tools for assessing the toxicological effects of environmental contaminants. We suggest that research aimed at developing and optimizing techniques for behavioral analysis could prove extremely useful to the field of toxicology, but that future work must be directed at determining what specific behaviors are most sensitive to various classes of contaminants, and at understanding the relevance of changes to discrete behaviors for influencing organismal and population-level health and fitness.