铅暴露的环境健康风险评估模型的本土化研究

我国现阶段重金属污染引发的群体事件频繁发生,其中铅污染事件尤为突出和严重。铅污染暴露对儿童健康损害的严重性、不可逆性以及铅污染后果的积累性和潜伏性特点,使得铅暴露的环境健康风险评估对中国的铅污染防治具有重要意义。目前,国际上最常用的铅污染暴露的儿童健康风险评估模型是美国EPA开发的IEUBK模型。为使IEUBK模型在中国得到更好的应用,本文首先对美国IEUBK模型系统做出如下本土化:1鉴于中国儿童的饮食结构、生活习惯及暴露参数等方面与欧美儿童存在的差异,对IEUBK模型暴露模块中的膳食模块和土壤-灰尘模块的数学模型进行改进;2探讨IEUBK模型中生理毒物代谢多隔室模型的高速精确的迭代算法。即针对生理毒物代谢多隔室模型的线性特征,通过离散化方法转化为线性方程组,引进中间变量,设计出了不需要进行高阶矩阵计算、存贮量较小、计算速度快且大样本模拟计算时优点明显的模型求解的一次迭代算法;3根据改进后的模型算法,编制模型的底层代码程序,并优化设计出友好的IEUBK模型系统中文输入界面。接着,对本土化IEUBK模型系统进行测试,测试结果表明:模型迭代算法的计算快速、结果准确,输入界面友好。然后,对本土化IEUBK模型进行实证分析,实证结果显示:本土化IEUBK模型的血铅预测值与血铅实测值的统计学差异并不显著。因此,本土化的IEUBK模型可在中国推广应用。最后,本文探讨了本土化的IEUBK模型系统的进一步改进方向及其在中国环评、环境标准制定及环境诉讼等方面的应用。     

Umbilical cord blood mercury levels in China

Mercury (Hg) is a well-known neurotoxicant. Hg exposure at high levels can harm individuals of all ages. Even low level exposure to Hg can damage the brain of fetuses and young children, and affect their central nervous system and cognitive development. The aims of our study were to measure total Hg levels in infant umbilical cord blood and to investigate the risk factors associated with total Hg cord blood levels in various cities in China. Our goal was to provide clues for the prevention of Hg exposure in utero. The results indicated that the average cord blood mercury levels (CBMLs) were (1.81 ± 1.93) μg/L, which were lower than those found in most previous studies. The concentrations also differed according to geographic region. The CBMLs were not only associated with family economic and living conditions, but also with diet in pregnant women, especially the intake of marine fish, shellfish, poultry, formula milk and fruits.     

Effects of amine, amine salt and amide on the behaviour of carbon dioxide absorption into calcium hydroxide suspension to precipitate calcium carbonate

The amount of carbon dioxide （CO2） absorption and calcium ion （Ca^2＋） concentration besides the pH of aqueous solution were observed during the COz absorption to precipitate calcium carbonate （CaCO3） from calcium hydroxide （Ca（OH）2）. A reaction rate-limiting effect of an amount of CO2 absorption without any organic additives in the early stage of the precipitation was observed, which was attributed to an interruption effect of bicarbonate ion （HCO3） on the precipitation of CaCO3. The improvement for the reaction rate was achieved not only by amine additives but also by neutral additives such as ε-caprolactam or amine salt. When the hexamethylene diamine was dissolved in the solution, successive change of crystal forms of CaCO3 aragonite to calcite in aqueous suspensions, confirmed by Ca^2＋ concentration change and X-ray diffraction, was concluded that a local environment around the amine group in aqueous solution and an interaction of the diamine with precipitated CaCO3 particles were important factors for these reactions.     

羧基改性阴极对微生物电合成系统产乙酸性能的影响机制

微生物电合成系统(microbial electrosynthesis systems,MESs)可利用微生物将二氧化碳转化为有价化合物,有望实现温室气体的资源化利用,然而,其合成效率仍需进一步提高.本研究通过电化学还原重氮盐反应将特定的官能团—COOH接枝到碳布电极表面,探究改性阴极对于MESs性能的影响.结果发现,经—COOH改性的阴极材料亲水性显著提高,而循环伏安扫描电流变弱. MESs在启动阶段性能差异最大,运行48 h,改性组CA-H、CA-M、CA-L的产氢速率是CK的21. 45、28. 60和22. 75倍;运行120 h,CA-H、CA-M和CA-L的乙酸累积浓度是CK的2. 01、2. 43和1. 44倍. MESs运行324 h后,各阴极的电化学活性无明显差异,生物膜蛋白量无明显差异(～0. 47 mg·cm~(-2)).阴极生物膜的群落结构分析发现,属水平上由Acetobacterium、norank_p_Saccharibacteria和Thioclava占据主导,总相对丰度占到59. 6%到82. 1%;各阴极之间产乙酸功能菌Acetobacterium的相对丰度差别不大(31. 3%～40. 1%),而消耗乙酸的norank_p_Saccharibacteria属在CA-H、CA-M、CA-L和CK的相对丰度分别为:16. 1%、24. 6%、31. 1%和37. 5%.羧基改性阴极对MESs的启动阶段影响较大,可为MESs的快速启动提供新的思路.     

Heavy metals in maternal and cord blood in Beijing and their efficiency of placental transfer

This study aimed to determine the effect of exposure to heavy metals in pregnant women in Beijing, China. We also evaluated the association of these heavy metals with birth weight and length of newborns. We measured the levels of 10 heavy metals,including lead(Pb), titanium(Ti), manganese(Mn), nickel(Ni), cadmium(Cd), chromium(Cr), antimony(Sb), stannum(Sn), vanadium(V), and arsenic(As), in 156 maternal and cord blood pairs. An inductively coupled plasma mass spectrometry method was used for measurement. Pb, As, Ti, Mn, and Sb showed high detection rates( 50%) in both maternal and cord blood. Fourteen(9%) mothers had blood Pb levels greater than the United States Center for Disease Control allowable threshold limit for children(50 μg/L).In prenatal exposure to these heavy metals, there was no significant association between any heavy metal and birth weight/length. Moreover, we estimated the placental transfer efficiency of each heavy metal, and the median placental transfer efficiency ranged from 49.6%(Ni) to 194%(Mn)(except for Cd and Sn). The level and detection rate of Cd in maternal blood were much higher than that in cord blood, which suggested that Cd had difficulty in passing the placental barrier. Prospective research should focus on the source and risk of heavy metals in non-occupationally exposed pregnant women in Beijing.     

Cytotoxicity and autophagy induction by graphene quantum dots with different functional groups

Graphene quantum dots(GQDs) possess great potential in various applications due to their superior physicochemical properties and wide array of available surface modifications.However, the toxicity of GQDs has not been systematically assessed, thus hindered their further development; especially, the risk of surface modifications of GQDs is largely unknown. In this study, we employed a lung carcinoma A549 cells as the model to investigate the cytotoxicity and autophagy induction of three types GQDs, including cGQDs(COOH-GQDs), hGQDs(OH-GQDs), and aGQDs(NH_2-GQDs). The results showed hGQDs was the most toxic, as significant cell death was induced at the concentration of 100 μg/mL,determining by WST-1 assay as well as Annexin-V-FITC/PI apoptosis analysis, whereas cGQDs and aGQDs were non-cytotoxic within the measured concentration. Autophagy detection was performed by TEM examination, LC3 fluorescence tracking, and Westernblot. Both aGQDs and hGQDs induced cellular autophagy to various degrees except for cGQDs. Further analysis on autophagy pathways indicated all GQDs significantly activated p-p38 MAPK; p-ERK1/2 was inhibited by aGQDs and hGQDs but activated by c GQDs. p-JNK was inhibited by aGQDs and c GQDs, while activated by hGQDs. Simultaneously, Akt was activated by hGQDs but inhibited by aGQDs. Inhibition of autophagy by 3-MA significantly increased the cytotoxicity of GQDs, suggesting that autophagy played a protective role against the toxicity of GQDs. In conclusion, c GQDs showed excellent biocompatibility and may be considered for biological applications. Autophagy induction may be included in the health risk assessment of GQDs as it reflects the stress status which may eventually lead to diseases.     

我国3个城市人体血清中新型溴代阻燃剂水平趋势及分布特征

本研究检测分析了我国吉林省伊通满族自治县(YT)、湖南省怀化市(HH)、四川省甘孜藏族自治州(GZ)3个城市5个年龄段(≥60、50~59、40~49、30~39、20~29岁)人体混合血清中六溴苯(hexabromobenzene,HBB)、五溴甲苯(pentabromotoluen,PBT)、五溴苯(pentabromophenyl,PBBz)、四溴对二甲苯(tetrabromo-p-xylene,PTBX)等4种新型溴代阻燃剂(NBFRs)的含量水平.PBBz、PBT和HBB在人体血清中的检出率为100%.在3个城市中,NBFRs总含量、HBB含量、PBT含量、PBBz含量(除GZ外)均在年轻人群中有升高的趋势.在5个年龄段中,YT和HH均有明显的主要污染物,但GZ首要污染物不明显且4种NBFRs含量占比在5个年龄段中基本稳定.3个城市人体血清中NBFRs在5个年龄段中的组成分布呈现出不同的趋势,表明不同地区的污染来源不同.其中,工业较为发达地区(YT和HH)人体血清中NBFRs总含量高于欠发达地区(GZ)的水平.     

改进铁路餐饮服务经营安全监督管理的思考

阐述铁路餐饮服务监督管理工作中食用油及食品添加剂管理、旅游列车供餐及沿线伙食团管理、快餐配送及网络订餐、相关监督工作文书使用等,根据国家相关规定,结合铁路管理现状和工作实践提出了应对和解决建议。     

基于AHP的列车司机非技术技能综合评价模型

列车司机的非技术技能对保证驾驶安全、降低人因事故发生概率有至关重要的影响。为了客观、准确地评价列车司机的非技术技能,从决策能力、人际能力、自我管理和情景意识4个维度通过问卷对非技术技能的指标进行筛选,得到11个列车司机非技术技能指标;然后使用层次分析法建立非技术技能综合评价递阶层次模型,为了获得各层指标权重,结合群决策方法建立各层的判断矩阵,获得各层指标的权重,最终构建了列车司机非技术技能综合评价模型。该模型既可以分析导致人因事故的非技术技能因素,也能够用于列车司机的评价、选拔和培训。