云南酸控区土壤重金属释放特征及潜在风险

研究了云南省酸雨控制区3种土壤重金属Pb、Zn、Cu在模拟酸雨淋溶作用下的释放特征,并进行了酸雨淋溶前后的潜在风险评价.结果表明,重金属在模拟酸雨作用下很快溶出,约30 h后趋于平稳,3种重金属Pb、Zn、Cu最大累计释放量分别为102.32、52.19和70.54 mg/kg.不同pH下重金属的溶出趋势基本相同,重金...     

Optimized processing power and trainability of neural network in numerical modeling of Al Matrix nano composites

In this research, an experimental study of reinforcing alumina nano-particles into the aluminum alloy matrix was implemented to verify the accuracy of modeling results obtained by feed forward neural networks. Artificial neural network combined with numerical technique were used to predict the various parameters of mechanical properties such as hardness, tensile and compressive yield stress, UTS and elongation percentage. Much experimentation were taken to discover a suitable number of hidden neurons, avoid detraction from the trainability and enable feed forward neural networks to solve more complex problems. The predictions were found to be consistent with experimental measurements.     

Heavy metal removal and cyanide destruction in the metal plating industry: an integrated approach from egypt

Wastewater produced from a metal plating is a major environmental problem. Industrial auditing revealed that the main source of pollution mainly originated from rinsing water. The characterization of final effluent showed that it is highly contaminated with hazardous heavy metals and cyanide. The concentration of copper, hexavalent chromium, nickel, and cyanide in the rinsing water of metal plating department was 14.8, 40.9, 13.3, and 19 mg/l, respectively. The concentration of cyanide and zinc from the galvanizing department reached 60 and 80 mg/l. The remediation scheme included the application of in-plant control measures via changing the rinsing process followed by the destruction of cyanide and reduction of hexavalent chromium bearing wastes. The pretreated wastes were then mixed with other industrial wastes prior to a combined chemical coagulation-sedimentation using lime and/or lime in combination with ferric chloride. The results indicated that, after applying the waste minimization measures alone at the source, prior to final treatment of industrial waste, removal rates of cyanide, copper, nickel, and chromium concentrations were 23.2%, 14.9%, 32.3%, and 55.3%, respectively in the rinse water from metal plating department. Furthermore, the removal rates of cyanide and zinc in the galvanizing department reached 59.7% and 24.3. The integrated control measures and treatment scheme led to more than 99% removal of copper, nickel, chromium, and zinc, while the complete removal of cyanide was achieved in the final effluent.     

Source term characterisation using concentration trends and geochemical associations of Pb and Zn in river sediments in the vicinity of a disused mine site: Implications for contaminant metal dispersion processes

River sediment at a disused lead-zinc mine was analysed to provide an understanding of the chemical nature of the source term for contaminated sediment exported from the site. Changes in concentration and geochemical associations of Pb and Zn were measured using aqua regia digestion and the BCR sequential extraction procedure. Sediment in the immediate vicinity of the mine was highly contaminated with Pb (max. c. 11,000 mg kg⁻¹) and Zn (max. c. 30,000 mg kg⁻¹), but these values declined rapidly within 1 km of the mine due to dilution and hydraulic sorting. Lead fractionation changed from being predominantly in the reducible fraction to being in the acetic acid-extractable fraction, whereas Zn was predominantly in the residual fraction. This material is transported as fine sediment in the river system.     

Highly sensitive and selective determination of malathion in vegetable extracts by an electrochemical sensor based on Cu-metal organic framework

Abstract

This article demonstrates the first application of a copper-based porous coordination polymer (BTCA-P-Cu-CP) as a carbon paste electrode (CPE) modifier for the detection of malathion. The electrochemical behavior of BTCA-P-Cu-CP/CPE was explored using cyclic voltammetry (CV) while chrono-amperometry methods were applied for the analytical evaluation of the sensor performance. Under optimized conditions, the developed sensor exhibited high reproducibility, stability, and wide dynamic range (0.6–24?nM) with the limits of detection and sensitivity equal to 0.17?nM and 5.7 µAnMcm^?1, respectively, based on inhibition signal measurement. Furthermore, the presence of common coexisting interfering species showed a minor change in signals (<4.4%). The developed sensor has been applied in the determination of malathion in spiked vegetable extracts. It exhibited promising results in term of fast and sensitive determination of malathion in real samples at trace level with recoveries of 91.0 to 104.4%. (RSDs < 5%, n?=?3). A comparison of the two studied techniques showed that the HPLC technique is unable to detect malathion when the concentration is lower than 1.8?µM while 0.006 µM is detected with appropriate RSDs 0.2–5.2% (n?=?3) by amperometric method. Due to the high sensitivity and selectivity, this new electrochemical sensor will be useful for monitoring trace malathion in real samples.     

Physiological adaptations in the lichens Peltigera rufescens and Cladina arbuscula var. mitis, and the moss Racomitrium lanuginosum to copper-rich substrate

Two lichen species (Peltigera rufescens and Cladina arbuscula subsp. mitis) and one moss species (Racomitrium lanuginosum) growing on a copper mine heaps (probably 200–300 yr old) in the village of Špania dolina (Slovak Republic) were assessed for selected physiological parameters, including composition of assimilation pigments, chlorophyll a fluorescence, soluble proteins and free amino acid content. The lichen C. arbuscula subsp. mitis was collected also at a control locality where total copper concentration in the soil was approximately 3% that of the waste heaps. Concentrations of Al, Co, Cu, Ni, Sb and Zn were highest in thalli of Peltigera, while the moss Racomitrium contained the highest content of Fe and Pb. Thalli of Cladina contained less metals than the cyanolichen Peltigera, and except for Zn metal concentrations in Cladina from the control locality were lower than in thalli of the same species from copper mine heaps. Regardless of the species or locality, the composition of assimilation pigments and chlorophyll a fluorescence showed that the tested lichens and moss were in good physiological condition and adapted to increased copper levels in the soil. There were significantly different amounts of total free amino acids in Peltigera, Cladina and Racomitrium from the Cu-polluted field. However, differences in amount of free amino acids in control, as well as Cu-polluted thalli of Cladina were less pronounced.     

Trace metals assessment in water, sediment, mussel and seagrass species--validation of the use of Posidonia oceanica as a metal biomonitor

The accumulation of trace metals (Cd, Co, Cr, Hg, Ni and Pb) was measured in water, sediment, the mussel Mytilus galloprovincialis and the seagrass Posidonia oceanica. Samples were collected in three locations of the north-western Mediterranean (Canari, Livorno and Porto-Torres) which present different levels and sources of human impact. Analyses in the different compartments (water, sediment, M. galloprovincialis and P. oceanica) have allowed to identify Canari as the most Cd, Co, Cr and Ni contaminated site; Livorno as the most Hg contaminated and Porto-Torres as the most Pb contaminated. Furthermore, for the first time, metal concentrations found in P. oceanica have been compared with those found in the water column, in the sediment and in the recognized metal bio-indicator species M. galloprovincialis and the results obtained have led to the same conclusions. Thus, this study allows to validate the use of P. oceanica as metal biomonitor of coastal waters.     

鞍山市大气尘和金属元素沉降通量及污染特征

通过采集鞍山市11个点位的降尘样品以及土壤样品,用ICP-MS分析了Cu、Mn、Zn、Pb等元素含量,并计算其沉降通量。结果表明,鞍山地区大气降尘的沉降通量为2.92～59.8g/(m2.month),其中鞍钢厂区沉降通量均值为31.6g/(m2.month),分别是周边地区和对照地区的4.72倍和10.5倍。重金属As、Cr、Pb和Cd的沉降通量分别为3.78、45.5、42.8、0.457g/(hm2.month)。降尘中各元素的富集系数为0.29～190,其中Cu、Fe、Zn、Mo、Cd、Pb和Se的富集系数大于10,说明这些元素主要来自于人为源。鞍钢厂区土壤中Cu、Pb、Mn、Zn、Mo、Cd、Ca、Fe和Se的含量较辽宁省土壤背景值高,说明其土壤环境已经受到了人类活动的影响。     

重金属致毒的化学机理

结合Pb(Ⅱ)对Ca(Ⅱ)生理活性的抗拮,取代金属对锌酶活性的影响,以及Hg(Ⅱ)和Pb(Ⅱ)对巯基(—SH)的亲合而致毒等实例,论述了分子水平上的金属致毒机理中,生物大分子配体的特殊结构与金属离子的电子结构所起的重要作用      

活性污泥胞外聚合物的组成与结构特点及环境行为

在活性污泥处理系统中,微生物大多以污泥絮体的形式悬浮在水中。胞外聚合物(EPS)作为污泥絮体的重要组成部分,以其独特的聚合结构和化学组成,在污水生物处理系统中起到重要作用。为了更好的描述EPS的环境行为,文章综合了近年来国内外相关的研究成果,首先分析了EPS的来源、化学组成及结构分布,得出EPS中包含蛋白质、多糖、腐殖酸、核酸、糖醛酸及脂类大分子等化学物质,其中蛋白质和多糖之和占总有机物含量的70%~80%;在结构上,EPS分为SB-EPS、LB-EPS和TB-EPS,三者与细胞结合的紧密程度递增,其中所含化学成分比例的不同将使其具有不同的理化特性。其次,文章对EPS的理化特征对污水处理系统的影响,如对系统中微生物降解特性的影响、磷和重金属的吸附等进行了讨论,并总结了EPS中相关的官能团对上述环境行为的贡献。同时,文章还论述了EPS中官能团的亲疏水特性及化学成分对污泥絮体的脱水性、絮凝沉降性能的影响。