Vertical distribution of polycyclic aromatic hydrocarbons (PAHs) in Hunpu wastewater-irrigated area in northeast China under different land use patterns

The concentrations of polycyclic aromatic hydrocarbons (PAHs) were determined in groundwater and soil profiles from upland field and paddy field in the Hunpu wastewater-irrigated area of northeast China. In the study area, the peak concentrations of total PAHs were within or just below the topsoil, and the contents decline with depth at various trend verified by the Spearman's rank correlation test. The total PAH concentrations in upland soil layers ranged from 46.8 to 2,373.0 microg/kg (dry wt.), while the concentrations in paddy soil layers ranged from 23.1 to 1,179.1 microg/kg (dry wt.). The 16 priority PAHs were all detected in the analyzed soil samples, and naphthalene (Nap), phenanthrene (Phe), fluoranthene (Fla), chrysene (Chr), and benzo[a]pyrene (Bap) were selected for further study in terms of their vertical distributions. The concentrations of both total and individual PAHs in upland soil were generally higher than those in the corresponding layers of paddy soil. The concentrations of total and individual PAH were notably different between the corresponding horizons in upland and paddy soil were probably attribute to the different sources and properties of the PAHs and soil; different methods of soil tillage and plant growing. Special PAH compound ratios, such as phenanthrene/anthracene, fluoranthene/pyrene, LMW/HMW, and parent PAH ratios (Ant/178, Fla/202, BaA/228, and Ilp/276) were used to identify the source of soil PAHs. The data suggests that the possible sources of PAHs in the Hunpu wastewater-irrigation area are the incomplete combustion of coal, petroleum and crude oil, automobile exhausts. These sources lead to pollution of the soil and groundwater by wet/dry deposition and vertical downward migration.     

天山中部山区不同胸径天山云杉对气候的响应

运用树木年轮气候学的方法,研究天山中部山区天山云杉(Picea schrenkiana)不同胸径年表特征以及与气候因子之间的关系,揭示不同胸径云杉对气候因子的敏感度差异,以及胸径大小因素对年表的潜在影响.结果表明:(1)云杉敏感度与胸径大小有线性负相关关系,说明小胸径云杉与气候变化关系密切;(2)不同胸径云杉年表对气候因子的响应存在一致性,均表现为对上一年月降水与月平均温度存在显著的滞后作用,与上一年8月降水以及当年4、5月降水正相关,与上一年8、9月平均温度负相关,与当年生长季温度负相关;(3)不同胸径云杉年表对气候响应存在一定的差异,大胸径云杉主要是对上一年8月、当年5月降水的正响应,对月平均温度无显著的响应关系,而小胸径云杉不但对上一年8月和当年4、5月降水有显著的响应关系,对当年5月平均温度也有显著的负响应关系.因此,在树木年轮气候学研究中应该考虑胸径大小因素对年表的影响.     

旅游景区标识系统的个性化实现路径研究——以三峡车溪民俗旅游区为例

旅游景区标识系统在展示景区形象、引导和管理旅游者、提升旅游者体验等方面具有重要作用,规范化与个性化是其设计的基本要求.在阐明景区标识系统的个性化内涵基础上,探讨了基于文化符号的个性化实现路径;以三峡车溪民俗旅游区为例,对其标识系统进行了个性化改进设计,以期为景区标识系统个性化建设提供理论指导和经验借鉴.     

剩余污泥对酸性大红G的吸附

以剩余污泥为吸附剂,研究其对模拟废水中酸性大红G的吸附条件及吸附机理。结果表明,剩余污泥对酸性大红G的吸附是一个快速过程,吸附时间可控制在30 min;其吸附过程同时受液膜扩散和颗粒内扩散的影响,可以用假二级动力学模型进行描述和预测;Freundlich方程可以较好地描述剩余污泥对酸性大红G的吸附行为。污泥未调pH时,对pH<2的溶液中酸性大红G的吸附性能良好;污泥pH为1时,对实验范围(pH<11)溶液中的酸性大红G均可有效吸附;污泥投加量增加,酸性大红G去除率升高,但污泥对酸性大红G的吸附量下降。     

改进的遗传算法在城市污水处理厂区间数优化设计模型中的应用

对于高度非线性的城市污水处理厂区间数优化设计模型(IPODM),若采用传统的方法求解,不仅计算繁琐,且难以有效地寻找全局最优解.本文通过引入遗传算法(GA),与传统的步长搜索法相结合,大大提高了问题的求解效率.本文给出了这种改进算法在某一城市污水处理厂优化设计中的应用实例.结果表明,不仅解的搜索效率有明显的提高,而且目标函数值在原有的基础上改进了20%,有着显著的经济效益;但是由于遗传算法自身的局限性,所求得的解只是一定条件下的最优区间解.     

香烟侧流烟中超细颗粒物释放及衰减特性

超细颗粒物(Ultrafine Particles,UFPs)能够进入人体肺泡组织进而危害人体健康,为了解香烟侧流烟中UFPs数浓度和表面积浓度释放及衰减特性,结合环境舱和现场实验结果对不同品牌香烟颗粒进行了分析.结果表明:燃烧过程中UFPs数浓度和表面积浓度峰值粒径分别为47.5~66.3 nm和85.6~100.5 nm,衰减2 h后,数浓度和表面积浓度峰值粒径仍小于200 nm;不同品牌香烟侧流烟中UFPs数浓度和表面积浓度释放速率分别为4.22×10~(12)~5.23×10~(12)个·min~(-1)和5.95×10~(10)~6.90×10~(10)μm2~·min~(-1),根据该释放速率模拟得到的不同换气率条件下UFPs数浓度衰减趋势与实验结果相符;通风和实验环境均会影响UFPs的衰减速率,随着换气率由0.7次·h~(-1)增至7次·h~(-1),侧流烟中UFPs的衰减时间由3 h降低至40 min,吸附作用的存在亦会加快UFPs的衰减速率.     

Cell concentration, viability and culture composition of airborne bacteria during a dust event in Beijing

Airborne bacteria were measured when a dust storm passed Beijing in spring 2012 with a focus on cell concentration,viability and TSA-and R2A-cultured strain composition.The concentration varied at an order of 10~7 cells/m~3 with dust loading(demonstrated with PM_(10))and they had a very close correlation(R_T~2 = 0.91,p 0.01).At the time of highest PM_(10) of652 μg/m~3,the bacterial concentration reached 1.4 × 10~8 cells/m~3,which was larger than that before and after the dust event by one order.Bacterial viability,the ratio of number concentration of viable cells to total cells,was 32%-64%and smaller in the dust plume than that before the dust arrival.Bacterial strains from the culture ranged between 2.5 x 104 and4.6×10~5 CFU/m~3 and no correlation with PM_(10) was determined.Their composition was different before and after the dust arrival according to 16SrRNA gene sequences and strains belong to Actinomycetes and Firmicutes were the majority in the dust samples.     

海岸带污染负荷预测模型及其在渤海湾的应用

针对海岸带及其近岸海域污染的特点,建立旨在为污染负荷总量的控制与削减以及在不同部门的重新分配提供技术手段和科学依据的海岸带水污染负荷预测模型．该模型涵盖了海岸带区域的主要污水排放部门,综合采用统计回归、灰色预测等方法,解决了由于数据缺乏或相互关系不明确而带来的环境系统的不确定性问题,并依据天津市污染负荷历年统计数据对模型加以验证．通过对天津市近岸海域近10年氮、磷、石油类和耗氧有机物排放量估算结果可以看出,万元产值工业废水排放量逐年下降,耗氧有机物排放量逐年缓慢增长．在污水排放总量中,有2／3的耗氧有机物和75％以上的氮来自于生活污水,因此天津市应重点控制生活污水排放．     

农业废物好氧堆肥过程因子对细菌群落结构的影响

采用聚合酶链式反应-变性梯度凝胶电泳(PCR-DGGE)技术研究了农业废物堆肥过程中细菌种群随时间的变化.同时,应用Quantity One2.0和Canoco4.5软件对获得的堆肥细菌种群数据与堆肥过程因子:环境温度、堆体温度、pH、含水率、水溶性有机碳(WSC)、C/N、水溶性氨氮(NH4+-N)和硝氮(NO3--N)进行冗余分析,并做出样点、种群与堆肥过程因子的二维排序图.结果表明,细菌群落(样点)以堆肥过程因子为梯度大体可划分为升温期(1～2d)、高温期(3～11d)、降温期(12～18d)和腐熟期(19～36d)4个阶段,每一阶段均有对应种群存在.不同的堆肥过程因子对细菌种群的影响大小依次为:NO3--N堆体温度WSCC/NNH4+-N含水率pH环境温度,其中,堆体温度、WSC、NO3--N、NH4+-N对细菌种群的影响极显著(p0.01),C/N、pH对细菌种群的影响显著(p0.05),含水率、环境温度对细菌种群的影响不显著.     

基于主成分分析的上海春季近地面臭氧污染区域性特征研究

为研究上海春季近地面臭氧污染的区域性特征,对长三角地区55个城市国控站点及上海市54个城市监测站点2016年5月的臭氧监测网络数据进行主成分分析(Principal Component Analysis,PCA),并将分析结果与气象条件进行综合分析,结果表明,主成分分析在不同的空间尺度下可以解析出行为模式不同的臭氧生成及传输来源主成分,且在较大的空间尺度下可以解析出区域背景臭氧浓度.长三角地区春季区域臭氧特征复杂,存在9个主成分,第一主成分所能解释的背景臭氧浓度在68.8～154.7μg·m~(-3)之间,而上海市主成分解析结果较为集中,仅能解析出两个主成分,且第一主成分即可解释90.5%的臭氧.对比同时段长三角及上海市主成分分析解析结果,上海市春季臭氧污染主要受到来自海洋的东南风影响,高浓度臭氧污染的本地生成贡献显著.