南岳森林群落生物多样性研究(Ⅰ)广济寺森林群落学特征

根据我们对南岳广济寺森林群落的实地考察及其调查资料统计分析结果,发现该群落是一种尚未报道的新类型,即水丝梨+甜槠-尾叶山茶+花竹-蔓赤 车群丛(Association of Sycopsis sinensis+Castnopsis eyeri-Camellia caudata+Phyllostachys nidularia-Pellionia scabra)。该群落内有维管束植物69科116属149种;其属的区系是以热带性质成分为主,温带性质成分为辅,各占56.19％和43.81％;其种的区系成分以华夏、东亚、中国-日本和华东至华中等四种类型为主,同时本群落具有明显的华东至华中过渡交迭性质。在群落中木本植物和草本植物各占71.14％和28.86％,草本植物中的多年生和一年生类型各占22.82％和6.04％。本群落可以明显划分为乔、灌、草三个层次,每个层次又可以进一步划分为三个亚层。这一群落是中亚热带东部典型常绿阔叶林北部植被地理亚带中的常绿阔叶林,在演替过程中,群落仍将保持以水丝梨为优势种的常绿阔叶林,但其亚优势种——甜槠将可能会被多脉青冈、中华石楠、长叶石栎取代。     

红壤坡地不同土地利用类型地表产流特征

在自然降水条件下,连续8 a对红壤丘陵坡地6种不同利用方式下的地表径流进行观测分析.结果表明,自然恢复保护能显著减少地表径流量,不同土地利用类型间地表径流量存在显著差异,其大小依次为:农作区＞甜柿区＞茶园区＞湿地松区＞干扰恢复区＞恢复区.各土地利用类型地表径流量存在明显的季节分布特征,产流主要发生于4-8月,降雨量和2.5～8.0 mm·h-1降雨强度是影响径流量的关键因素.恢复区和干扰恢复区呈现良好的水土保持效应,累积径流量增长缓慢;纯林生态系统水土保持效应与林木种类密切相关;农耕地由于土壤扰动大,水土流失严重,累积径流量增长迅速.必须通过构建合理的农林复合生态系统以进一步防治南方地区的水土流失.     

Kinetics of quinoline degradation by O3/UV in aqueous phase

The kinetics of quinoline degradation by O3/UV in aqueous phase was studied in this paper. It was found that the stoichiometric factor for the number of ozone molecule consumed by per quinoline molecule was 1. The second-order rate constants at 15 degrees C for the direct reaction of quinoline with ozone and that for the reaction of quinoline with *OH were determined to be 51.0 and 7.24 x 10(9) M(-1)s(-1), respectively. In O3/UV reaction system, *OH was the more important oxidant to degrade quinoline than ozone. For a comparison, in O3 reaction system, the relative importance of the two oxidants depended on the pH value greatly. To make the degradation of quinoline more practical, improvement of the concentration of *OH is more feasible.     

Human exposure and health risk of alpha-, beta-, gamma- and delta-hexachlorocyclohexane (HCHs) in Tianjin, China

The dynamic exposures to HCHs of individuals born between the years 1913 and 1993 in Tianjin have been simulated by connecting a fugacity model (IV) with a multimedia exposure model. Ingestion is the most important pathway for human beings to take up HCHs, and concentrations in the human body correlate with body weight changes. Accumulations of HCHs were derived assuming that the degradation in human body behaved linearly. The health risk of exposure to HCHs was measured using cancer risk and loss of life expectancy (LLE), and LLE was modified from its original definition to incorporate a dynamic calculation that takes variances in exposure into account. Monte-Carlo simulations were run to analyze the uncertainties of the model.     

利用有机基质厌氧生物产氢的试验研究

对利用有机基质厌氧生物产氢过程进行了试验研究 ,结果表明 ,污泥种类、基质种类、基质浓度和起始 p H对厌氧产氢反应有显著影响。当校河底泥在以 2 0 g COD/L的果糖为基质 ,起始 p H为 6.5时 ,产氢效果最佳 ,停滞期仅为 5 h,产气速率高达5 0 .1m L/g VSS·h,且可持续 12 h,累积产气量高达 60 4.9m L/g VSS,其中氢气含量约为 5 0 %。半连续试验的结果表明 ,若及时更换和补充基质 ,适当调节 p H,就可实现持续产氢 ,在 16h内平均产气速率可达 60 .0 m L /g VSS· h,氢气含量约为 45 %。     

化学氧化剂对水华蓝藻的控制研究

对比了过氧化氢（H₂O₂）、高铁酸钾（K₂FeO₄）和过碳酸钠（Na₂CO₄）3种氧化剂对自然水体中群体蓝藻生长和光合活性的影响.结果发现,3种氧化剂对蓝藻均有快速的抑制效应,且随着氧化剂浓度的增加抑制效果增强.相同氧化剂浓度下,H₂O₂对水华蓝藻的去除能力强于K₂FeO₄和Na₂CO₄,对蓝藻光合系统Ⅱ的最大光量子产量（F_v/F_m）和有效光量子产量（F_v'/F_m'）的抑制效果也更显著.H₂O₂对不同浓度水华蓝藻的控制实验结果表明,初始藻细胞浓度对H₂O₂控藻效果影响较大,细胞密度越大,H₂O₂降解率增加,抑藻效果急剧下降.当初始藻密度为10μg/L和100μg/L,5mg/L H₂O₂的48h降解率分别为64.9%和97.5%,对藻细胞F_v/F_m的抑制率分别为10%和1%.因此,实施H₂O₂控制蓝藻水华的措施应该尽量在蓝藻水华形成早期,即藻密度较低的时候使用.     

石化污水处理场挥发性有机物排放状况研究

采用便携式气相色谱-质谱联用仪时石化污水处理场排放的挥发性有机物的排放状况进行了测定.检测出的挥发性有机物中以烷烃和芳香烃为主,总浓度随污水处理工艺流程逐级降低.芳香烃的质量分数为33.23%～84.73%.     

Concentrations of heavy metals and polycyclic aromatic hydrocarbons in needles of Masson pine (Pinus massoniana L.) growing nearby di erent industrial sources

Emissions from industrial activities pose a serious threat to human health and impose the need for monitoring both inorganic and organic pollutants in industrial areas.We selected Masson pine (Pinus massoniana L.) as potential biomonitor and collected the current (C) and previous year (C+1) needles from three industrial sites dominated by petrochemical, ceramics manufacturing, and iron and steel smelting plants and one remote site to determine heavy metals (Cu, Cd, Pb, Zn, Cr, Ni and Co) and polycyclic aromatic hydrocarbons (PAHs) in unwashed and water-washed needles. Both unwashed and washed C+1 needles showed generally higher concentrations of heavy metals and PAHs than C needles, although the washed needles more clearly spotlighted the accumulation e ect of PAHs over exposure time. Water-washing resulted in a significant decrease in needle PAH concentrations with more significant e ects shown in C needles. By contrast, needle heavy metal concentrations were much less a ected by washing. Although heavy metals and PAHs might di er in adsorption and uptake strategies, their higher concentrations in the needles at the industrial sites indicated conspicuous contamination due to industrial emissions there. The PAH distribution patterns in pine needles accorded with the real types of energy consumption in the study sites and were e ciently used for pinpointing local pollutant sources.     

水中重金属在线监测技术发展概述

近年来重金属污染事件层出不穷,重金属污染的监测已经成为国家和人民关注的重点问题。介绍了水中重金属在线监测仪器的主要应用技术,并指出技术的适用范围和优劣点,同时对水质重金属在线监测仪的发展前景提出几点意见。     

基于双向门控循环单元的地表水氨氮预测

为提高水环境中NH4+-N的预测精度,提出了一种互补完全集合经验模式分解(CCEEMDAN)和双向门控循环单元(BiGRU)神经网络的混合预测模型(CCB).首先,通过CCEEMDAN将NH4+-N数据分解成一系列较为简单的模态成份;然后利用BiGRU神经网络对各成份进行预测,将所有分解成份的预测结果相加即可获得最终预...