水中氨氮测定用纳氏试剂配制的探讨

纳氏试剂的配制是试验能否成功的关键.本文从纳氏试剂配制的反应机理分析,从理论和实践上探究了影响试剂配制的因素及解决的方法,得出了最佳的配制比例,并对细节注意事项进行了总结.     

Influence of Motivations for Seeking ISO 14001 Certification on Perceptions of EMS Effectiveness in China

This study examines the motivations of mainland Chinese facilities in seeking ISO 14001 certification and examines the linkages between these motivations and self-reports of the effectiveness of major environmental management system (EMS) components. In a sample of 128 facilities in Beijing, Shanghai, and Guangzhou, the main drivers for certification were reported to be to ensure regulatory compliance, to enhance the firms reputation, and to improve environmental performance, in that order. Although motivation to achieve cost reductions were least emphasized, a broad range of motivations appears to be considered in the decision to seek certification to ISO 14001. Regression models linking these motivations to the EMS components suggests that internal motivations have an influence on most EMS components. One interesting exception to this, however, is that no significant relationship was observed between internal motivations and the promulgation of environmental objectives and targets. The relationships associated with external motivations for certification (i.e., those in response to customer and other stakeholder pressures) and EMS components, on the other hand, are weaker and tend to occur earlier in the process cycle. No significant relationships were found between motivations to reduce costs and perceptions of the effectiveness of EMS components. Overall, these findings suggest that ISO 14001, as currently being implemented in mainland China, may have a modestly useful role when used in combination with other policy mechanisms to move the Chinese economy toward more sustainable practices. It is asserted that the ISO standard could provide even greater benefits if Chinese registrars were more proactive in developing EMS in conjunction with even more rigorous third-party audits.Published online     

FeS引发储油罐着火温度动态变化曲线的研究

储油罐着火事故被推测是由硫腐蚀产生的FeS氧化引起的。笔者阐述了储罐中FeS形成的原因 ,并采用自然发火绝热测试系统对FeS自然氧化进行 1 9h的跟踪实验 ,观察FeS绝热氧化过程中温度动态变化特性。实验发现 ,FeS氧化由诱导氧化期、中速氧化期和加速氧化期 3个阶段组成。诱导氧化期是积蓄能量 ,激发FeS活性的过程 ,试样温度基本未发生变化 ;中速氧化期是FeS试样表面的分子活性被激发 ,与FeS试样表面吸附的氧气发生氧化反应的过程 ,温度增加较慢 ;加速氧化期是FeS分子内部的活性被激活并进行氧化反应的过程 ,温度迅速升高。结果证明 :随着反应的进行 ,温度随反应时间变化的幅度越来越大 ,氧化反应的反应热不能及时散开而急剧地积累 ,温度急剧地升高 ,将引起油品自燃。此外 ,通过X衍射图和氧化升温曲线证明 ,水是影响FeS氧化的重要因素。     

铅蓄电池企业废气中铅及其化合物便携式XRF检测方法

在企业污染源现场实现污染物排放浓度水平的快速判定和超标风险筛查,对生态环境管理部门提高执法效率、企业提高环境管理水平意义重大。铅是一种对人体危害极大的有毒重金属,目前缺少含铅废气中铅及其化合物的便携式直读检测设备和检测方法。探索性地将X射线荧光光谱(XRF)法应用于铅蓄电池企业含铅废气中铅及其化合物的便携式快速、直读检测。研究结果表明,基于XRF的面密度法适用于铅蓄电池企业含铅废气处理设施后铅及其化合物的快速、直读检测,相对国标方法具有快速、直读、对样品无损、便于复测等特点,可用于铅及其化合物排放浓度水平的快速判定和超标风险筛查。     

Survey of phthalate pollution in arable soils in China

The problem of pollution by phthalates is of global concern due to their widespread occurrence, toxicity and endocrine disruption properties. The contamination by phthalates such as dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP) and di(2-ethylhexyl) phthalate (DEHP) in 23 arable soils throughout China was investigated to evaluate the present pollution situation. The survey results demonstrated that phthalates were ubiquitous pollutants in soils in China. The total concentrations of phthalates differed from one location to another, and ranged from 0.89 to 10.03 mg kg(-1) with a median concentration of 3.43 mg kg(-1). Among the phthalates, DEHP was dominant and detected in all 23 soils. DEP and DBP were also in abundance, and DMP was rarely detected. Similar contamination patterns were observed in all 23 soils. A distinct feature of phthalate pollution in China was that the average concentration in northern China was higher than that in southern China. In addition, a close relationship was observed between the concentration of phthalates in soils and the consumption of agricultural film. The correlation showed that the application of agriculture film might be a significant pollution source of phthalates in arable soils of China. The potential risk of phthalates in soils was assessed on the basis of current guide values and limits.     

悬浮液进样石墨炉原子吸收法直接测定土壤、底泥中的铅、镓、钴、镍

介绍一种悬浮液进样直接测定土壤、底泥中多种微量金属元素的快速分析方法。基体改进剂的使用，适宜的原子化温度的选择，使用水相标准溶液作校准曲线成为可能．对标准作品的测定证明了此方法的精密度和准确度较好，适合于常规环境样品分析．     

用科学管理的手段控制呼和浩特市二氧化硫污染

呼市的二氧化硫污染比较严重，呼市政府结合城市建设，确定了污染源控制思路，强化管理，二氧化硫的治理工作取得了显著成绩，已达到国家空气质量二级标准。本文分析了目前二氧化硫防治面临的问题，对进一步开展治理工作提出了有益的建议和对策。     

二氧化硫对棉花叶片光谱反射特性的影响

在动态熏气箱中对棉株进行SO_2处理(2ppm,8小时).测定叶片光谱反射率和微分光谱.受SO_2伤害的棉叶光谱反射率发生变化:在可见光部分,反射率普遍增加;在近红外部分,反射率降低.整个光谱反射曲线发生蓝移,初步确定几个波段可用于区别污染的与正常的棉叶光谱反射特性.     

Streamwater chemistry and flow dynamics along vegetation-soil gradient in a subalpine Abies fabri forest watershed, China

Streamwater chemistry and spatial flow dynamics from a subalpine Abies fabri forest in an experimental watershed located in the east slope of Gongga Mountain were analyzed to gain insights into the gradient effect of primary community succession on the stream biogeochemical process. Results showed that high sand content (exceeding 80%) and porosity in the soil(exceeding 20% in A horizon and 35% in B horizon), as well as a thick humus layer on the soil surface, made the water exchange quickly in the Huangbengliu (HBL) watershed. Consequently, no surface runoff was observed, and the stream discharge changed rapidly with the daily precipitation. The flow trends of base ions in the stream water were influenced by the Abies fabri succession gradient. Ca^2 , HCO3^- and SO4^2,- were the dominant anions in the streamwater in this region. A significant difference of Ca^2 , HCO3^- and SO4^2- concentration exported between the succession stages in the watershed can be found. But they had the similar temporal change in the stream flow. Ca^2 , HCO3^- and SO4^2- showed significantly negative correlations with the daily precipitation and the stream discharge. Concentrations of Cl^- , Na^ , K^ , and Mg^2 were low in all streamwaters monitored and we observed no differences along the Abies fabri succession gradient. Low ratios of Na. (Na Ca) (range from 0.1 to 0.2) implied cations were from bedrock weathering (internal source process in the soil system) in this region. But, a variance analysis showed there were almost no differences between rainwater and streamwaters for Mg^2 , Na^ , K^ , and Cl^- concentrations. This indicated that they might be come from rainfall inputs(external source). The highly mobile capacity, rapid water exchange between precipitation and discharge, and long-term export lead to this observed pattern were suggested.     

典型耐候钢在江津大气环境中暴晒1 a的腐蚀行为

目的 研究3种典型耐候钢在江津大气环境中暴晒1 a的初期腐蚀行为。方法 采用户外大气挂片、腐蚀质量损失、SEM、XRD、电化学等方法,研究Q355NH、Q460FRW、Q690的腐蚀速率、锈层形貌、锈层物相和锈层电阻,并与Q345碳钢进行对比。结果 耐候钢和碳钢在大气暴晒初期的腐蚀规律是一致的,Q355NH、Q460FRW、Q690和Q345碳钢的腐蚀速率分别为0.050 9、0.053 6、0.047 8、0.055 mm/a,Q690的腐蚀速率最小,约为碳钢的87%。耐候钢和碳钢的锈层都主要由α-FeOOH、γ-FeOOH和Fe₂O₃组成,耐候钢的锈层更致密,裂纹更少。Q355NH、Q460FRW、Q690的锈层电阻值分别为821.3、1 005、1 080?·cm²,碳钢为101.68?·cm²,耐候钢的锈层电阻值约为碳钢的10倍。Cr和Cu元素在耐候钢的锈层中富集明显。结论 耐候钢的腐蚀速率低于碳钢,3种耐候钢的耐蚀性顺序为Q690>Q355NH>Q460FRW。Cr和Cu元素在...