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31.
Accumulations of polychlorinated dibenzo-p-dioxins, dibenzofurans and coplanar polychlorinated biphenyls were analyzed in common carp (Cyprinus carpio) collected in the Hikiji River, Kanagawa Prefecture, Japan in which dioxin contaminated effluent was released during the period starting from November 1992 to March 2000. Higher levels of 2,3,7,8-tetrachlorinated dibenzo-p-dioxin toxic equivalents were observed in carps collected downstream to the dioxin release site (contaminated site) than the reference site. Modulations of cytochrome p450 (CYP) enzyme in liver, serum estrogen concentration and gonadal somatic index (GSI) were also measured as biomarkers for the contaminants. Total CYP content in livers was markedly higher in male and female carps from the contaminated site relative to the reference site fish. The expression level of the cytochrome p450 1A and Ethoxyresorufin O-deethylase activity were significantly higher in female carps from the contaminated site than from the reference site. A lower level of plasma estrogen was observed in carps from the contaminated site. The GSI in female carps from the contaminated site was smaller than that recorded at the reference site. The present study indicates that dioxins released to the Hikiji River might induce the CYP enzyme and inhibit the reproductive functions in common carps dwelling downstream from the release site.  相似文献   
32.
日本关东南部冬季飘尘中有机碳和元素碳污染现状研究   总被引:3,自引:0,他引:3  
气溶胶中常含有一定的碳化合物,其中最主要的为有机碳(OC)和元素碳(EC),它们主要来源于化石燃料燃烧等人为活动,并强烈地影响着气溶胶的污染性质。日本关东平原南部初冬季节常发生高浓度飘尘污染,在对这种污染现象的研究中分析了OC和EC在飘尘中的含量,结果表明OC和EC是飘尘中重要的组成部分,二者之和可占质量浓度的20%左右,这也从一个侧面揭示了飘尘的污染状况和污染来源。   相似文献   
33.
The bio-briquette technique which mixes coal, biomass and sulfur fixation agent and bio-briquettes under 3-5 t/cm^2 line pressure has aroused people‘s attention in view of controlling the air pollution and the acid rain. In this paper, the physicochemical properties of bio-briquette and its ash were investigated. And the acid soil was improved by the bio-briquette combustion ash, which contained nutritive substances such as P, N, K and had the acid-neutralizing capacity(ANC). The pH, EC, effective nutrient elements(Ca, Mg, K, P and N), heavy metal elements(AI, Cu, Cd, Cr, Zn and Mn) and acid-neutralizing capacity change of ash-added soils within the range of 0-10%, were also studied. Specially, when 5% bio-briquette combustion ash was added to the tested soil, the content of the effective elements such as Ca, Mg and K rose by 100 times, ? times and twice, respectively. The total nitrogen also increased by about twice. The results showed the oxyanions such as that of AI, Cu, Cd, Cr, Zn and Mn were not potentially dangerous, because they were about the same as the averages of them in Chinese soil. It is shown that the ANC became stronger, though the ANC hardly increases in the ash-added soil. On the basis of the evaluation indices, it is concluded that the best mixture ratio is to add 2.5%--8% of the bio-briquette combustion ash to the tested soil.  相似文献   
34.
The effect of particle density on the turbulent open-channel flow carrying dilute particle suspensions is investigated using two specific gravities and three concentrations of solid particles. The particles, identical in size and similar in shape, were natural sand and a neutrally buoyant plastic. The particles were fully suspended, and formed no particle streaks on the channel’s bed. Accordingly, the changes in the flow are attributed to the interactions between suspended particles and flow turbulence structures. Measurements were obtained by means of image velocimetry enabling simultaneous, but distinct, measurement of liquid and particle velocities. The experimental results show that, irrespective of particle specific gravity, particle suspension influences bulk velocity of flow and the Kármán coefficient, while friction velocity essentially remains constant. The results also show that particles in suspension modify local water turbulence over the flow depth, but in ways not accurately predicted using the customary parameters for characterizing turbulence modification.  相似文献   
35.
IntroductionRecently ,nonylphenolpolyethoxylates (NPnEO (n :numberofethoxyunits(EOs) )havebecomeaproblematicissueforthereasonthatthesecompounds,animportantgroupofnonionicsurfactants ,havebeenusedwidelyinvariousindustriesasflocculants,dispersants,emulsifie…  相似文献   
36.
偏振激光雷达在沙尘暴观测中的数据解析   总被引:12,自引:5,他引:12  
阐述了日本国立环境研究所(NIES)研制的双波长偏振激光雷达的工作原理和主要工作参数,探讨了激光雷达方程在沙尘暴监测中的应用条件,并对激光雷达获取的各种信息进行直观图视化处理.分别用光学强度、后向散射强度、退偏振率、消光系数以及双波长信号比等对沙尘天气的污染特征进行了解析,并对垂直方向沙尘浓度的分布进行了计算.研究表明:退偏振率大于10%时,即可判断为沙尘天气;双波长信号比(P(1 064)/P(532))大于0.4,则表示该期间为沙尘天气;利用消光系数表示气溶胶浓度时,NIES激光雷达观测沙尘气溶胶消光系数超过0.3 km-1(ρ(TSP)约为500 μg/m3),且持续时间超过3 h的沙尘天气现象即可判断为一次沙尘事件.根据激光雷达特有物理量对沙尘气溶胶的不同判定标准,对沙尘事件的强度、持续时间、沙尘云厚度以及沙尘天气的污染特征进行了解析和探讨.   相似文献   
37.
Comprehensive temperature monitoring was done in an in-vessel forced-aeration static-bed composting process using sewage sludge. The three layers that divided the compost pile horizontally showed different temperature distributions. The temperature of the top layer appeared not to be influenced by the ambient temperature. The temperature of the center area of the top layer was taken to be the representative temperature for evaluating composting start-up performance. The temperature of the bottom layer was strongly influenced by the ambient temperature, and the temperature of the center area of the bottom layer was taken to be the representative temperature for pathogen control as it was the minimum temperature in the reactor. Composting start-up performance was influenced by several factors when the ambient temperature was either below or above 20°C. When the ambient temperature was below 20°C, the time taken to reach 65°C (T 65) was influenced by the temperature of inflowing air, but when the temperature was higher than 20°C, it was influenced by the ratio of sewage sludge to seed compost (F/S). T 65 was least when F/S was 1–2. Received: January 9, 2001 / Accepted: October 10, 2001  相似文献   
38.
This paper introduces an integrated water management model at the industrial park level. It suggests four approaches to water management: first, direct water reuse among users; second, water reuse among users by blending with freshwater; third, water reuse between users and a wastewater treatment plant; and fourth, groundwater recharge by reclaimed wastewater or other feasible applications in order to optimize the overall water efficiency. The model results in a comprehensive management methodology for optimizing water resources within an industrial park, seeking potential water reuse among industries, and incorporating the size and cost of reclaimed wastewater delivery systems. A case study is employed to test the model’s feasibility. An economic analysis of the optimized water use network is also carried out, showing the potential water and cost savings.  相似文献   
39.
Coralliophila abbreviata (Lamarck) is a corallivorous gastropod that lives and feeds on several species of scleractinian coral in the Western Atlantic and Caribbean. Previous studies of C. abbreviata have revealed that snails on branching acroporid corals are larger and consume more tissue than those on massive and plating corals. To ascertain whether snail life-history and fitness are differentially affected by the coral host, an analysis of the age structure and female reproductive output of snail populations on three coral host taxa (Acropora palmata, Diploria spp., and Montastraea spp.) was conducted at four shallow (2–7 m depth) reef sites off Key Largo, Florida in June through August, 2004. Snails were, on average, almost twice as large on A. palmata than on Diploria spp. and Montastraea spp., averaging 30.3 mm shell length, compared to 17.2 and 17.6 mm, respectively. Brood size increased as a power function with female shell length. Females on A. palmata were significantly larger than females on the other two hosts and, therefore, produced more offspring per female. The number of growth striae on the inner surface of the operculum was used to estimate snail age. Estimates of growth rate were obtained by fitting the Gompertz growth function to size-at-age plots and mortality was estimated using growth parameters and size-frequency data. The data suggest that C. abbreviata inhabiting A. palmata are larger than on alternative hosts due to a combination of a faster growth rate and longer life-span. The species is believed to be a protandrous hermaphrodite. The timing of sex change varied among hosts; snails on A. palmata changed sex later at larger sizes relative to those on the other two hosts. Based on these results, it seems probable that C. abbreviata has developed reaction norms for life-history traits, allowing snails to adjust and maximize fitness in the different environments associated with various coral hosts.  相似文献   
40.
The feasibility of the use of short-wavelength UV (254+185 nm) irradiation and TiO2 catalyst for photodegradation of gaseous toluene was evaluated. It was clear that the use of TiO2 under 254+185 nm light irradiation significantly enhanced the photodegradation of toluene relative to UV alone, owed to the combined effect of photochemical oxidation in the gas phase and photocatalytic oxidation on TiO2. The photodegradation with 254+185 nm light irradiation was compared with other UV wavelengths (365 nm (black light blue lamp) and 254 nm (germicidal UV lamp)). The highest conversion and mineralization were obtained with the 254+185 nm light. Moreover, high conversions were achieved even at high initial concentrations of toluene. Catalyst deactivation was also prevented with the 254+185 nm light. Regeneration experiments with the deactivated catalyst under different conditions revealed that reactive oxygen species played an important role in preventing catalyst deactivation by decomposing effectively the less reactive carbon deposits on the TiO2 catalyst. Simultaneous elimination of photogenerated excess ozone and residual organic compounds was accomplished by using a MnO2 ozone-decomposition catalyst to form reactive species for destruction of the organic compounds.  相似文献   
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