Determination of low levels of free fibres of chrysotile in contaminated soils by X-ray diffraction and FTIR spectroscopy

A new analytical method for the determination of low levels (0.01–1 wt%) of free fibres of chrysotile in contaminated clayey, sandy and sandy-organic soils is described. The detection limit of 0.01 wt% is reached with an enrichment of free fibres of chrysotile in the sample using a standard laboratory elutriator for sedimentation analysis. The chrysotile quantitative determination is performed both by X-ray powder diffraction, using the internal standard and reference intensity ratio methods, and by Fourier-transform infrared absorption spectroscopy. The procedure can be successfully applied to different soils after removal, by a thermal treatment, of the matrix components which can interfere. This straightforward method fulfils the request of public institutions and private companies for an appropriate quantitative determination of chrysotile-free fibres in contaminated soils.     

土壤环境中铅的化学

论述了环境中铅的背景值、来源、污染、质量标准、化学循环以及环境中铅的烷基化，为铅污染治理提供理论依据。     

Monitoring of Fe,Mn, Cu,Pb and Cd levels in two brown macroalgae from the Bulgarian Black Sea coast

Heavy metal contents (Fe, Mn, Cu, Pb and Cd) were determined in two brown macroalgal species (Cystoseira crinita and Cystoseira barbata). Samples were collected during six seasons from spring 1996 to summer 2000 from five different sites of the Bulgarian Black Sea coastal zone – Tuzlata, Ravda, Sozopol, Ahtopol and Sinemoretz. The local and seasonal metal distribution and their variations were examined.

The data obtained indicate that the two investigated species demonstrate various degrees of metal accumulation and can be used as indicators for the type and quantity of anthropogenic contamination in marine ecosystems.     

Monitoring and Evolution of the Pollution by Volatile Organic Compounds (Vocs) in the Groundwaters of The Najerilla River Basin (Spain)

VOCs were detected and identified in the water of several wells in the area of Nájera (La Rioja). The past uncontrolled spills from an important painting and varnishing industry and from other smaller ones devoted to the manufacture of furniture and varnishing activities were the sources of the VOCs plume detected in this aquifer. This article shows the results obtained in the monitoring and assessment of the pollution at 18 sampling points for more than a year. It has allowed us to study the evolution of the different pollutants and the influence of a remediation process applied by the company in the main pollution source. The analytical method is based on headspace-solid-phase microextraction (SPME) using a 75-μm carboxen-polydimethylsiloxane fibre. Quantification was carried out by gas chromatography with flame ionization detection. This method has allowed us to determine the 13 VOCs identified in the polluted underground samples providing good sensitivity (LOD between 0.1 and 6.0 ng/mL) and reproducibility (r.s.d. less than 10%).     

Trends in the monitoring of legacy and emerging organic pollutants in protected areas

Protected Areas (PAs) are locations for conservation, internationally recognized for their natural, ecological, and/or cultural values. Human presence in PAs is generally limited to minimal or banned exploitation of natural resources. However, different threats to PAs are evident as a result of short and long-range transport of organic pollutants of legacy and emerging concern. There has been a shift of interest in legacy pollutants such as persistent organic pollutants (POPs) to emerging compounds, resulting in a need for improved monitoring strategies in PAs. Here, we highlight the main advances in environmental analytical chemistry for legacy and emerging pollution monitoring in PAs. Trends in sampling, sample preparation and instrumental determination of multiclass organic pollutants in biotic and abiotic matrices are presented and discussed. Here, we considered the most relevant and recent literature regarding organic pollutants in PAs from terrestrial to aquatic landscapes collected within 2015 to the present time frame.     

陶瓷微滤膜在液相领域的分离机理和控制分析

介绍了陶瓷微滤膜的过滤机理,分析了膜污染的现状及其影响陶瓷微滤膜膜通量的因素,总结了陶瓷微滤膜的应用前景和亟待解决的问题.     

Data assimilation and pollution forecasting in Burgers' equation with model error function

This article presents a correction method for a better resolution of the problem of estimating and predicting pollution, governed by Burgers' equations. The originality of the method consists in the introduction of an error function into the system's equations of state to model uncertainty in the model. The initial conditions and diffusion coefficients, present in the equations for pollution and concentration, and also those in the model error equations, are estimated by solving a data assimilation problem. The efficiency of the correction method is compared with that produced by the traditional method without introduction of an error function.Three test cases are presented in this study in order to compare the performances of the proposed methods. In the first two tests, the reference is the analytical solution and the last test is formulated as part of the “twin experiment”.The numerical results obtained confirm the important role of the model error equation for improving the prediction capability of the system, in terms of both accuracy and speed of convergence.     

ICP-OES法测成都市三环内表层土壤13种金属元素含量

采用电感耦合等离子体发射光谱(ICP-OES)法同时测定成都市三环内表层土壤13种金属元素含量与分布.研究显示,重金属元素As、Cr、Cu、Ni、Pb、Zn平均含量分别为24.3mg/kg,154.0 mg/kg,32.8 mg/kg,31.4 mg/kg,64.9 mg/kg,165.1 mg/kg.Mn、Mo、Fe平均含量分别为400.1 mg/kg,10.7 mg/kg,18911 mg/kg.Sr 74.0 mg/kg、Sb 4.9 mg/kg、Co 13.7 mg/kg、Sc 5.9 mg/kg.采用单项污染指数法和内梅罗综合污染指数法来评价土壤重金属污染程度,并针对表层土壤金属污染状况进行了讨论.     

改进的随机蛙跳算法对农机润滑油污染浓度的近红外光谱检测研究

润滑油是农业机械正常作业的必要物资,农业机械发动机工作的动力性、安全性、经济性以及寿命与润滑油状况有着紧密联系。污染浓度作为油液的综合评价指标,常规的实验室检测耗时长、成本高,所以开发高效的润滑油污染浓度检测技术具有重要意义。提出了一种基于近红外光谱技术的农机润滑油污染浓度的检测方法,同时针对随机蛙跳(RF)特征波长选择算法中迭代次数大,结果再现性低等缺点,提出了一种迭代保留信息变量的随机蛙跳(IRIV-RF)特征波长选择算法。该算法一方面利用迭代保留信息变量(IRIV)算法提取出强信息变量和弱信息变量,将其作为RF算法中的初始变量集,消除初始变量集的随机性对结果再现性的影响。另一方面通过对变量按被选概率值由大到小正向排序后,从首个波长开始依次增加一个波长建立偏最小二乘回归(PLSR)模型,选择交叉验证均方根误差(RMSECV)值最小时的变量子集为特征波长,消除RF算法所提取的特征波长数量的不确定性。利用近红外光谱仪采集自行配制的101份不同污染浓度的农机润滑油原始光谱数据,选用三种不同的预处理方法分别对原始光谱进行处理,确定最佳的预处理方法为变量标准化(SNV)。在此基础上通过RF,...     

环境水镉污染应急处理的药物及条件挑选

探讨了硫酸铝、聚铝、聚铁对环境水体中的镉的沉淀能力,实验证明当在实际环境水样品中调节pH在7-9之间,聚铁或聚铝能对环境水体中的镉很好的沉淀作用,短期作用比较明显,药剂能在30min左右达到2h的处理效果的70%-90%,而长期作用后(18h)能将水体中的镉降低到10μg/L以下,一立方水的用药量在100-400g之间就可以到达很好的处理效果,而且无二次污染,可为环境水中镉污染的应急处理药品.