Exploring the linkages between river water chemistry and watershed characteristics using GIS-based catchment and locality analyses

A typology of land characteristics for the Humber catchment in central/eastern England is identified in relation to land use, hydrology and demographic, topographic and geological characteristics, using GIS and statistical analyses. Empirical relationships between land characteristics and water quality were examined in relation to the spatial variability in water quality across the Humber catchment. Analyses of relationships between land characteristics and water quality were undertaken at two hierarchical scales: (1) individual catchments and (2) localities of 10 km radius draining to each sampling site. The importance of urban and agricultural sources was identified, together with a hydrological component linked to dilution of point source inputs and mobilisation of specific sediment-associated contaminants in higher-energy (higher-flow) environments. High-solubility (dissolved) chemical determinands (such as B, Cl and SO₄), which undergo conservative transport through the river network, show the strongest linkages with land characteristics at the catchment scale. Cr, Zn and Ca show stronger correlations with land characteristics at the locality rather than the catchment scale, indicating that the concentrations of these determinands are more closely linked to the availability of localised sources. This work provides a starting point for investigating how changes in land use and management of drainage basins might impact river water quality at the regional scale and fluxes to the coastal zone, by providing a mechanism for examining linkages between regional-scale land characteristics and river water quality. The next step requires development of the approach within a more rigorous statistical framework and the extension of the regional analysis within a wider national and international context. Electronic Publication     

Point patterns of forest fire locations

In this paper I demonstrate some of the techniques for the analysis of spatial point patterns that have become available due to recent developments in point process modelling software. These developments permit convenient exploratory data analysis, model fitting, and model assessment. Efficient model fitting, in particular, makes possible the testing of statistical hypotheses of genuine interest, even when interaction between points is present, via Monte Carlo methods. The discussion of these techniques is conducted jointly with and in the context of some preliminary analyses of a collection of data sets which are of considerable interest in their own right. These data sets (which were kindly provided to me by the New Brunswick Department of Natural Resources) consist of the complete records of wildfires which occurred in New Brunswick during the years 1987 through 2003. In treating these data sets I deal with data-cleaning problems, methods of exploratory data analysis, means of detecting interaction, fitting of statistical models, and residual analysis and diagnostics. In addition to demonstrating modelling techniques, I include a discussion on the nature of statistical models for point patterns. This is given with a view to providing an understanding of why, in particular, the Strauss model fails as a model for interpoint attraction and how it has been modified to overcome this difficulty. All actual modelling of the New Brunswick fire data is done only with the intent of illustrating techniques. No substantive conclusions are or can be drawn at this stage. Realistic modelling of these data sets would require incorporation of covariate information which I do not so far have available.

Gas-phase and aerosol chemistry interactions in South Europe and the Mediterranean region

The atmospheric chemical composition is affected by the interaction mechanisms among gases and particulate matter through a wide range of chemical reactions that can occur with the aid of particulate matter (e.g. particles act as reacting or absorbing surfaces) or be influenced by the presence of particulate matter in the atmosphere (photochemical reactions). Physical and chemical processes are also bonded in an interactive way that often leads to the influence of the radiation budget, cloud physics and the warming or cooling of the lower atmospheric levels. The Euro-Mediterranean region is a key-sensitive area due to the unique climatic and air quality characteristics associated with the regional climatic patterns, geomorphology (land and water contrast) and coexistence of pollutants from different origin. Focusing on this region, the gas-aerosol interactions are studied using state-of-the-art atmospheric and chemical transport modeling tools following the necessary development in the chemical transport model CAMx. Sensitivity and large-scale simulations have shown significant responses of the modeling system to the inclusion of natural species emissions, the direct shading effect of dust particles on photochemical processes and the formation of new types of aerosols through heterogeneous uptake of gases on dust particles. Including such interactions in the chemical transport model often led to the improvement of the model performance compared with available measurements in the region.     

Heavy metal concentrations in plants and different harvestable parts: A soil-plant equilibrium model

A mathematical interaction model, validated by experimental results, was developed to modeling the metal uptake by plants and induced growth decrease, by knowing metal in soils. The model relates the dynamics of the uptake of metals from soil to plants. Also, two types of relationships are tested: total and available metal content. The model successfully fitted the experimental data and made it possible to predict the threshold values of total mortality with a satisfactory approach. Data are taken from soils treated with Cd and Ni for ryegrass (Lolium perenne, L.) and oats (Avena sativa L.), respectively. Concentrations are measured in the aboveground biomass of plants. In the latter case, the concentration of metals in different parts of the plants (tillering, shooting and earing) is also modeled. At low concentrations, the effects of metals are moderate, and the dynamics appear to be linear. However, increasing concentrations show nonlinear behaviors.     

Study of sorption kinetics of some ionic liquids on different soil types

In the present contribution sorption kinetics experiments under static conditions were utilized in three selected ionic liquids cations (1-ethyl-3-methylimidazolium, 1-butyl-3-methylimidazolium, 1-hexyl-3-methylimidazolium chlorides) study with five type of soil, differing in total organic carbon (TOC) content. The experimental results indicate the sorption capacity growth with increase in TOC content and hydrophobicity of ionic liquid cation. The obtained kinetic sorption parameters as well as distribution coefficients (K_d) were used to estimate the sorption properties of the soil types towards the ionic liquids in question. The Gibbs free energy values indicate that ionic liquid cations sorption on soils could be generally considered as a physical adsorption with exothermic effect. But the values of −dG for studied cations sorption on soil with very high of TOC content in soil (45%) may testify to nature of chemical adsorption. Sorption of the analyzed compounds occurs probably by means of hydrogen bonds, electrostatic and π  π interaction with the organic matter and the clay minerals of the soils.     

除草剂苯达松与腐植酸作用机理的研究

采用ＩＲ，ＥＳＲ，ＵＶ等近代仪器分析手段，对除草剂苯达松与２种不同来源的腐植酸的作用机理进行了研究。结果表明，苯达松与腐植酸作用时，因腐植酸所含官能团各类，数量不同，形成不同的吸附机理，含有羟基较多的腐植酸ＨＡ１，易与苯达松形成离子键，氢链是其可能的吸附机理；而含有胺基和低羧基的腐植酸ＨＡ２，则易与苯达松以氢键相结合，苯达松与腐植酸作用时，两者之间发生了电荷转移，形成了更大的共轭体系。     

Adsorption of basic dyes onto MCM-41

The adsorption of two basic dyes, Basic Green 5 (BG5) and Basic Violet 10 (BV10), onto MCM-41 was studied to examine the possible effect of interactions between large adsorbates and MCM-41 on the pore structure stability of MCM-41 and the potential of MCM-41 for the removal of basic dyes from wastewater. The revolutions of surface characteristics and pore structure of MCM-41 induced by dyes adsorption were characterized based on the analyses of the nitrogen isotherms, the XRD patterns, and the FTIR spectra. It was experimentally concluded that when the effect of interactions between large dyes (such as BV10) and MCM-41 on the pore structure stability of MCM-41 was insignificant, MCM-41 might be a good adsorbent for the removal of basic dyes from wastewater. The adsorption of BV10 on MCM-41 with respect to contact time, pH, and temperature was then measured to provide more information about the adsorption characteristics of MCM-41. Both Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms and the pseudo-second-order kinetic model was used to describe the kinetic data, from which some adsorption thermodynamic parameters were also evaluated.     

光催化氧化/吸收工艺处理垃圾焚烧发电厂恶臭废气

我国南方某城市垃圾焚烧发电厂采用光催化氧化技术/吸收工艺联用技术对难降解恶臭气体进行高效处理,大大提高了恶臭气体的去除效率,实现了该行业废气的无害化处理,取得了良好的效果。运行结果显示,光催化氧化技术/吸收工艺联用技术能实现难降解恶臭气体的高效处理,排放废气可达到《恶臭污染物排放标准》(GB14554-93)中的二级标准。     

Dealing with uncertainty in qualitative models with a semi-quantitative approach based on simulations. Application to the Gironde estuarine food web (France)

In the context of ecosystem approach to fisheries, it is a critical issue to build management tools able to predict the possible trajectories of ecosystems under various human pressure or environmental variations, but also capable to point out influent and sensitive components.     

细水雾灭火技术的研究

细水雾灭火技术主要通过汽化隔氧、冷却燃料和氧化剂以及吸收部分热辐射等效应与火相互作用,降低燃烧化学反应速率和火焰传播速率,达到控制和扑灭火灾的目的,不会产生“二次性环境污染”,可以达到火灾防治洁净化目标。为此,对细水雾抑制火灾的过程和机理进行了实验研究和数值模拟,以促进细水雾灭火技术的发展