Deterioration of Polyamideamine–Epichlorohydrin (PAE) in Aqueous Solutions During Storage: Structural Changes of PAE

Structural changes of polyamideamine–epichlorohydrin (PAE) in solution during storage at 4 °C and pH 4.2–4.5 for up to 8.9 years were studied by ¹H- and ¹³C-NMR analyses, colloidal titration and others. NMR signals due to 3-hydroxy-azetidinium groups of PAE decreased during storage, and correspondingly 2, 3-dihydroxypropyl groups were formed by the ring opening. The content of 3-hydroxy-azetidinium groups in PAE determined by ¹H-NMR were similar to that determined by the colloidal titration, although the former was higher than the latter. About 50% of the 3-hydroxy-azetidinium groups present in the fresh PAE were lost during storage for 8.9 years. Furthermore, ¹³C-NMR analysis revealed that significant depolymerization of polyamideamine chains occurred by hydrolysis of the amide linkages during storage. Rough evaluation of number average degree of polymerization (DPn) of the amideamine repeating unit showed that the DPn decreased from 12 to 2 during storage for 8.9 years.     

抓好班组长培训夯实安全生产基础

班组长综合素质的高低,可影响安全生产.试图通过叙述抓好班组长培训与搞好安全生产的辩证关系,以期引起工业企业对抓好班组长培训工作的重视.     

欧美水质大肠菌群相关检验标准探究

对欧美水质大肠菌群检验的相关内容进行分析探讨,重点剖析了总大肠菌群、粪（耐热）大肠菌群、大肠埃希氏菌等检测项目的内涵、检测意义。以及它们之间的内在联系。介绍了大肠菌群检测指标在欧关的发展应用情况,以及当前大肠菌群标准检测技术方法。对我国水质大肠菌群标准体系提出要求。     

海洋溢油对浮游生物种群的影响

随着溢油风险的不断加大,对溢油产生的环境损害的研究也日益增多,由于溢油对海洋生态系统的多元影响,短期和长期影响的差异,使溢油环境损害赔偿变得非常困难,因此有必要对溢油对浮游生物种群的长期影响进行系统研究。本文对溢油对浮游生物影响现有的研究进行概括和综述。并以3．24事故为例对溢油对浮游生物的长期种群结构影响进行研究,分析是否产生影响。分析1998年事故发生时及事故后历史数据以及近几年的监测数据,进行对比试图解决如下问题：浮游生物在生物量上是否有变化？产量是否变化？种群结构是否发生变化？种群的主导物种是否变化？最后对这些结论的原因进行了探讨。     

对苯二甲酸、乙二醇和氢化三联苯对职业人群健康影响的研究

目的研究长期接触对苯二甲酸、乙二醇、氢化三联苯对职业人群健康状况的影响,为职业健康监护提供依据。方法采用职业流行病学的方法,在对某化纤公司进行劳动卫生学调查的基础上,分析对苯二甲酸、乙二醇、氢化三联苯接触工人心血管系统及肝肾功能的变化。结果接触组平均接触工龄为16年,接触组和对照组人群高血压检出率分别为13．41％,19.21％;接触组WBC、RBC、HGB、PLT、ALT、GGT、ALP、HBsAg异常检出率分别为9．76％,13．12％,8．66％,11．17％,19．83％,14．24％,2．51％,8.38％;对照组上述指标的异常检出率分别为13．36％,9．09％,11．76％,12．29％,19．25％,13．36％,1．61％,9.09％。经统计学检验。两组人群各检出率无明显差异（P〉0．05）。结论对苯二甲酸、乙二醇、氢化三联苯在很低浓度情况及企业做好防护措施的情况下对职业人群的心血管系统及肝肾损害不大。     

基于群决策的河流允许排污量公平分配博弈模型

为解决河流水质管理中允许排污量的公平分配问题,建立一个由排污者群体决策的博弈模型.其基本原理是在现有被普遍接受的公平分配准则基础上,排污者按照一定的顺序,根据个体利益最大化原则依次选择分配准则并获得相应的允许排污量,同时考虑所有排序方式,求取平均值作为最终分配结果.案例研究结果表明,模型综合考虑了多种分配准则,无需人为给定准则的权重,保证了分配依据和分配过程的公正,由排污者群体决策而得出最终结果,是一种较为公平合理的允许排污量分配方法.模型求解与博弈论的Shapley解法类似,计算量呈随排污者个数阶乘递增趋势.     

生态通道模型及其在水生态系统中的应用探讨

文章对生态通道Ecopath模型方法的提出及发展进行了简要介绍,并归纳了该方法在国内外水生态系统研究和管理中的应用,探讨了其应用过程中存在的问题。Ecopath模型目前主要应用在海洋生态系统中,因此在淡水生态系统应用具有一定的发展前景;在模型建立过程中,研究区域的生物种群动态及食性组成等基础研究的不足,会导致模型需要的食性数据难以获得,功能组的划分及数量较难把握,模型P/B、Q/B参数的计算及输入的准确性不高;对于Ecopath模型的敏感度分析、输入参数的不确定度分析及模拟效果的评估,在该模型发展及应用过程中将越来越受到关注。     

降低土壤中氟含量的生态地质学方法探讨

从生态地质学角度提出一种新型的降低土壤氟的方法,利用植物的根系分层特性研究植物对土壤氟进行吸收的功能,通过对研究区植被的根群特征进行调查分析,可以构建根群坝、农林复合系统等,人为地把氟在土壤包气带中由源到汇的运动过程进行层层拦截、吸收,实现对土壤氟经淋滤进入地下水的迁移过程分层、分阶段拦截的效果,从而达到降低土壤及农作物氟含量水平的目的。并根据南阳盆地不同的地貌提出了具体生态降氟的建设措施。     

Risk assessment for the daily intake of polycyclic aromatic hydrocarbons from the ingestion of cockle （Anadara granosa） and exposure to contaminated water and sediments along the west coast of Peninsular Malaysia

The concentration of carcinogenic polycyclic aromatic hydrocarbons (c-PAHs) present in the sediment and water of Peninsular Malaysia as well as in the cockle Anadara granosa was investigated. Samples were extracted and analysed with gas chromatographymass spectrometry. The concentrations of total carcinogenic polycyclic aromatic hydrocarbons (t-PAHs) were measured between 0.80 0.04 to 162.96 14.74 ng/g wet weight (ww) in sediment, between 21.85 2.18 to 76.2 10.82 ng/L in water samples and between 3.34 0.77 to 46.85 5.50 ng/g ww in the cockle tissue. The risk assessment of probable human carcinogens in the Group B2 PAHs was calculated and assessed in accordance with the standards of the United States Environmental Protection Agency (US EPA). Case I in the toxicity assessment analysed the cancer risk to consumers of Malaysian blood cockle. Case II assessed the risk of cancer from exposure to PAHs from multiple pathways. The average cancer risk of case I and case II were found to be classifiable as unsafe according to the US EPA standard. The cancer risk due to c-PAHs acquired by the ingestion of blood cockle was (8.82 0.54) 10??6 to (2.67 0.06) 10??2, higher than the US EPA risk management criterion. The non-cancer risks associated with multiple pathways in Kuala Gula, Kuala Juru and Kuala Perlis were higher than the US EPA safe level, but the non-cancer risk for eating blood cockle was below the level of US EPA concern.