七台河市大气污染特征及变化浅析

通过对七台河市2006年1月起空气连续监测系统正式运行以来的监测数据分析,归纳、总结七台河市大气污染物随季节变化规律,每日、小时变化规律及市区不同地区大气污染物分布特征,并对这种特征及变化规律进行分析.     

黄孢原毛平革菌在多种氨氮浓度下木质素降解酶的产生

在氨氮浓度0．0308-0．924g／L，下对黄孢原毛平革菌(Phanerochaete chrysosporium)在空气环境中进行自由悬浮振荡培养，在氨氮浓度0．0308-0．308g／L下可检测到木质素过氧化物酶活性，最高酶活为42．8U/L；在氨氮浓度0．0308g／L和0．154g/L下可检测到漆酶活性，最高酶活为35．0U／L，在氨氮浓度不低于0．154g/L时，葡萄糖消耗速率大致相当，明显高于在氨氮浓度0．0308g／L下的葡萄糖消耗速率；氨氮在葡萄糖耗尽时达到最低值，然后开始增大；木质素过氧化物酶和漆酶的活性峰与葡萄糖和氨氮的最大消耗基本对应。实验结果对木质素降解酶发酵和白腐真菌在环境工程中的直接应用具有启发意义。     

试论高等级公路的环境经济分析与实践

简要分析了公路工程环境经济分析的必要性,应用层次分析法(AHP)筛选出公路工程环境经济分析指标体系;应用环境经济学的方法初步探讨了公路工程建设的环境经济损失的价值评估方法和数学模型,以便在定量化评价中作指导和参考.     

Sorption kinetics of parent and substituted PAHs for low-density polyethylene (LDPE): Determining their partition coefficients between LDPE and water (KLDPE) for passive sampling

Low-density polyethylene (LDPE) has been widely used as a sorbent for passive sampling of hydrophobic organic contaminants (HOCs) in aquatic environments. However, it has seen only limited application in passive sampling for measurement of freely dissolved concentrations of parent and substituted PAHs (SPAHs), which are known to be toxic, mutagenic and carcinogenic. Here, the 16 priority PAHs and some typical PAHs were selected as target compounds and were simultaneously determined by gas chromatography–mass spectrometer (GC–MS). Some batch experiments were conducted in the laboratory to explore the adsorption kinetics of the target compounds in LDPE membranes. The results showed that both PAHs and SPAHs could reach equilibrium status within 19–38?days in sorption kinetic experiments. The coefficients of partitioning between LDPE film (50?μm thickness) and water (K_LDPE) for the 16 priority PAHs were in good agreement with previously reported values, and the values of K_LDPE for the 9 SPAHs are reported in this study for the first time. Significant linear relationships were observed, i.e., log K_LDPE?=?0.705?×?log K_OW?+?1.534 for PAHs (R²?=?0.8361, p?<?0.001) and log K_LDPE?=?0.458?×?log K_OW?+?3.092 for SPAHs (R²?=?0.5609, p?=?0.0077). The selected LDPE film was also proven to meet the condition of “zero sink” for the selected target compounds. These results could provide basic support for the configuration and in situ application of passive samplers.     

贵阳市秋冬季PM2.5中重金属污染特征、来源解析及健康风险评估

为掌握贵阳市大气PM_2.5中重金属的污染特征、潜在来源和健康危害,于2017年10月—2018年2月白天(08:00—19:00)、夜间(20:00—翌日07:00)连续采集秋、冬两季大气颗粒物PM_2.5样品(n=202),采用电感耦合等离子体质谱(ICP-MS)法,检测样品中10种重金属(Pb、Cd、Cr、As、Zn、Mn、Co、Ni、Cu和V)含量,分析其昼夜质量浓度特征及变化规律,运用PMF(正定矩阵因子分析)模型和HMHR(健康风险评价模型)分别探讨其来源及健康风险.结果表明:①秋、冬两季大气颗粒物ρ(PM_2.5)日均值分别为(53±18)(62±20)μg/m3,均低于GB 3095—2012《环境空气质量标准》二级标准(75 μg/m3);ρ(As)、ρ(Zn)和ρ(Mn)均呈冬季高于秋季的特征,其他元素变化不明显.②白天ρ(PM_2.5)为(61±20)μg/m3,稍高于夜间〔(58±24)μg/m3〕;ρ(Pb)白天低于夜间,ρ(Ni)、ρ(Mn)、ρ(Zn)和ρ(Cu)则白天高于夜间,其他元素昼夜质量浓度无明显差异.③PMF模型分析表明,交通污染、燃煤、工业冶金和土壤扬尘是采样期间10种重金属的主要来源,其贡献率分别为39%、37%、14%、10%.④HMHR结果表明,Cd和Mn对儿童存在非致癌风险,其他重金属元素对人群无非致癌风险.致癌元素As、Cr和Cd的致癌风险值介于4.3×10-6~4.4×10-5之间,对人群可能存在致癌风险;而Ni和Co的致癌风险值均低于可接受水平(10-6).研究显示,贵阳市秋、冬两季PM_2.5中重金属污染水平整体较低,交通污染和煤炭燃烧是其主要来源,重金属元素中Cd、Mn、As和Cr对人群存在一定的健康风险.      

Effect of initial temperature on the explosion pressure of various liquid fuels and their blends

In this work, the effect of initial temperature on the explosion pressure, P_ex, of various liquid fuels (isooctane, toluene and methanol) and their blends (isooctane-toluene and methanol-toluene, with three different fuel-fuel ratios) was investigated by performing experiments in a 20-l sphere at different concentrations of vaporized fuel in air. The initial temperature was varied from 333 K to 413 K.Results show that, as the fuel-air equivalence ratio, Φ, is increased, a transition occurs from a “thermodynamics-driven” explosion regime to a “radiant heat losses-driven” explosion regime. The maximum pressure, P_max, is found in the former regime (Φ < 3), which is characterized by a trend of decreasing P_ex with increasing initial temperature. This trend has been explained by thermodynamics. In the latter regime (Φ > 3), P_ex increases with increasing initial temperature. This trend has been addressed to the decrease in emissivity (and, thus, radiant heat losses) with the increase in temperature.     

基于低碳发展的企业资源损失定量分析及其应用

低碳经济是企业发展中面临的选择,但目前的研究却缺少企业产品生产过程中的资源消耗与环境影响问题之间的定量分析.另有研究发现,企业处于积极环境行为的第一个层次,即只要企业污染治理水平停留在企业污染治理边际成本和企业污染治理边际收益相等处,企业治理环境就是可以获得收益的,因而,企业有进行降低环境影响的强烈需求.本文运用物质流成本会计(MFCA),从数量与价值角度使企业资源损失定量化,使其损失结构清晰化,因此有利于企业找到损失改善点,促使企业减少资源的初始投入量、提高资源使用率,并降低环境影响.以一个案例进行具体运用,在此基础上,引入外部损害成本原理,通过"资源流内部损失-废弃物外部损害"双重维度分析,使企业资源损失从经济性和环境性方面得到全面体现.本文从微观层面为企业低碳经济发展提供了一个新的研究视角.     

Attenuation of N2O emission rates from agricultural soil at different dicyandiamide concentrations

An experiment was conducted to assess the role of different concentrations of dicyandiamide (DCD), a potent nitrification inhibitor, on temporal changes in nitrous oxide emission from sandy loam agricultural soil. It was found that with increasing concentration of DCD i.e. from 6 to 12% of nitrogen applied in the form of urea, there was a decrease in the both average and peak N₂O emissions. However, from 14% DCD treated soil, there was a non-significant alteration in the N₂O emission. Maximum average N₂O efflux of 217.55 μg m⁻² h⁻¹ was noted from control plots. As compared to control, there was an attenuation of 50, 58, 65, and 91% average N₂O efflux from 6, 8, 10 and 12% DCD applied pots, respectively, whereas, there was a negative average of N₂O efflux from the soil with 14% DCD treatment. The soil N content also showed a significant correlation with N₂O emission. Therefore, 12% DCD treatment has been found to be the best with regard to attenuation of nitrous oxide from sandy loam agricultural soils.     

巢湖水体散射和后向散射特性研究

湖泊水体散射特性的研究对湖泊水色要素遥感反演模型的发展具有重要的意义.本研究利用AC-S和ECO-BB9实测了巢湖水体的散射系数和后向散射系数,在分析光谱变化特性的基础上,构建了悬浮颗粒物散射系数和后向散射系数的幂函数光谱模型,获得的光谱指数分别为0.86和3.24.研究发现悬浮颗粒物散射系数与TSM和ISM都存在较好的线性函数关系,进而提出水体中总悬浮颗粒物的比散射系数为0.6364(10-3m2·mg-1),无机悬浮颗粒物的比散射系数为0.9108(10-3m2·mg-1).同时,分析了悬浮颗粒物后向散射率和折射指数的变化,其变化范围分别为0.003～0.026和1.02～1.06.     

三峡水库蓄水前后长江干流主要污染物浓度变化趋势分析研究

利用三峡库区长江干流1998年-2010年水质监测数据,以1998年-2003年代表蓄水前,2004年-2010年代表蓄水后,对比分析蓄水前后主要污染物浓度变化情况,用Spearman秩相关系数法判断其变化趋势的显著性。分析可知,蓄水后氨氮、化学需氧量、总磷指标的平均浓度要低于蓄水前,氨氮、化学需氧量浓度变化幅度大于蓄水前,总磷浓度变化幅度小于蓄水前;Spearman秩相关系数计算结果表明,三峡水库常年回水区内的断面,污染物浓度多数呈下降趋势,但只有晒网坝和培石断面的氨氮指标浓度下降趋势具有显著意义。