Use of pollution indices and ecological risk in the assessment of contamination from chemical elements in soils and sediments – Practical aspects

This paper presents a discussion involving practical aspects of applying contamination indices and ecological risk factors derived from chemical elements in the environmental assessment of soils and sediments. The single and integrated indices: Geoaccumulation index (I_geo), Enrichment factor (EF), Contamination factor (CF), Pollution Index (PI), Ecological risk factor (E_ir), Pollution Load Index (PLI), Degree of contamination (C_deg), Modified Contamination Factor (mC_deg), and potential ecological risk index (PERI) were discussed, and some applications were presented didactically. The analytical care needed to obtain reliable indices with the studied ecosystem is also evidenced. In addition, the advantages and limitations of the use of these indices are presented.     

Handheld device for fast and non-contact optical measurement of protein films on surfaces

Thin films of bacteria, proteins and other biochemical substances are almost always found on surfaces exposed to the environment. Optical methods enable innovative tools for the study of such films. Residua of proteins exhibit fluorescence when excited in the UV. We present a specially designed handheld measuring device that can detect organic contamination levels down to 100 ng/cm² with measurement times shorter than a second. Using time-correlated spectroscopy methods the fluorescence detection of contamination levels on surfaces is possible even if the fluorescence spectra of contamination and base material overlap. The results presented in this paper show that a detection of contamination levels of bovine serum albumine (BSA) down to 100 ng/cm² is possible on non-fluorescent materials. A theoretical analysis shows the possibility to detect BSA levels down to less than 1 ng/cm² with the presented setup. Future development of handheld optical devices suitable for the detection or analysis of various compounds can be based on these results. A compact formalism is suggested that can be used to calculate the minimal concentration of a given organic contamination that can be detected with a certain measurement setup.     

含弥散可压核废料污染问题的交替方向特征有限元格式及分析

对可压缩并含弥散的核废料污染问题,利用有限元块逼近技术提出了交替方向特征有限元格式,格式兼具特征线逼近技术及交替方向技术的优点,证明了格式的最佳H^1-收敛阶。     

A contamination carrying criterion for branched surfaces

A contamination in a 3-manifold is an object interpolating between the contact structure and the lamination. Contaminations seem to provide a link between 3-dimensional contact geometry and the classical topology of 3-manifolds, as described in a separate paper (Oertel and Świa̧tkowski, Contact structures, σ-confoliations, and contaminations in 3-manifolds. arXiv math.GT/0307177). In this article we deal with contaminations carried by branched surfaces, giving a sufficient condition for a branched surface to carry a pure contamination.     

Fruit Tree model for uptake of organic compounds from soil and air†

The current European risk assessment for chemicals considers only tap water, while in reality other beverages play an important role. A good part of beverages are made from fruits, for example apple juice and vine. A mathematical model was developed to predict uptake of neutral organic chemicals from soil and air into fruits. The new fruit tree model considers eight compartments, i.e. two soil compartments, fine roots, thick roots, stem, leaves, fruits, and air. Chemical equilibrium, advective transport in xylem and phloem, diffusive exchange to soil and air and growth dilution are the main processes. The parameterization is for a square-meter of an apple orchard. The model predicts that polar, non-volatile compounds will effectively be transported from soil to fruits, while lipophilic compounds will preferably accumulate from air into fruits. Results from various experiments show no disagreement with the model predictions.     

An investigation into possible sources of phthalate contamination in the environmental analytical laboratory

A study of common laboratory equipment and components was performed in order to identify sources of contamination of phthalates prior to testing environmental samples for such compounds. A screening study revealed significant leaching from laboratory consumables, such as plastic syringes, pipette tips released maximum leachings of 0.36?µg?cm^?2 diethylhexyl phthalate (DEHP) and 0.86?µg?cm^?2 diisononyl phthalate (DINP), plastic filter holders produced maximum leachings of 2.49?µg?cm^?2 dibutyl phthalate (DBP) from polytetrafluoroethylene (PTFE); specifically 0.61?µg?cm^?2 DBP from regenerated cellulose and 5.85?µg?cm^?2 dimethyl phthalate (DMP) from cellulose acetate and Parafilm® leached levels up to 0.50?µg?cm^?2 DEHP. In addition, a high-temperature bake-out process was found necessary to eliminate quite high levels of two phthalates present in a commercial bulking agent for pressurized liquid extraction.     

应用流体力学理论优化气流流型

洁净室的气流流型应以有效地排除污染粒子为优先。分析指出,气流流型应符合下述原则,即单向气流应接近流体力学中的渐变流和非单向气流尽量接近平面流动。     

负离子材料的净化研究

负离子材料是近年来材料科学中的热点,而负离子技术在洁净领域却发展缓慢。将对负离子材料净化空气的原理及净化效果进行探讨和研究。     

可压缩核废料污染问题的修正迎风差分格式及收敛性分析

对无弥散项的可压缩核废料污染问题模型建立修正迎风差分格式, 并进行了收敛性分析,最后给出其l^2误差估计.     

Correlation software algorithm for portable laser spectral analysis of heavy metal dopants

A novel correlation algorithm for laser spectral analyser (LSA) has been created for simultaneous determination of heavy metals' content in condensed matters, particularly in soils. This work is devoted to the design of a portable laser spectroscopy device for material contamination analysis using software with an original correlation algorithm. Detection sensitivity that can be achieved using this technique varies within 10–100 ppm. It has been demonstrated that acceptable results may be achieved during in-situ measurements. For a huge number of heavy metals, the limits of detection, which were determined experimentally with respect to unpolluted soil sample are lower. This system may provide fast in-situ analysis of heavy metal content and it uses optical fibre sensors.