电晕线加热降低负离子空气净化器臭氧浓度的实验研究

通过实验研究了臭氧浓度与电晕电流、电晕线线径、电晕线加热功率及供电电压间关系。结果表明：臭氧浓度随电晕电流线性增加；随电晕线线径的减小和电晕线表面温度的提高而下降；电晕线加热是降低负离子空气净化器的臭氧浓度的有效途径。     

南通市濠河水污染研究

本文采用系统聚类法对濠河水质进行了聚类分析，并且将濠河污染因子和监测断面的污染程度进行了分类．     

论建筑施工噪声管理中的执法对象

建筑施工噪声的执法对象是建设单位还是施工单位是长期未能统一的问题，分析两者在环境噪声污染防治中的责任与义务，阐述两者作为执法对象的利弊及法律依据，提出建设单位作为执法对象通过经济合同方式与施工单位进行环境责任与义务再分配的可行观战点，并建议对现行法律进行修改。     

地震台站如何做好防震减灾宣传科普工作

近年来，地震宣传科普工作越来越受到政府和地震部门的重视，作为地震监测系统的基本单位一地震台站如何在地震宣传科普工作发挥自己应有的作用，是一个很值得探讨的问题。本文根据地震台站自身特点和优势，从地震台站进行科普宣传工作的意义、内容、现状及建议等几个方面进行了一些探讨。     

溶氧及pH对地衣芽孢杆菌合成聚γ-谷氨酸的影响

在3.7L发酵罐中研究了溶氧、pH和甘油流加对地衣芽孢杆菌分批发酵生产聚γ-谷氨酸(γ-PGA)的影响.结果表明,当葡萄糖浓度为27.9g/L且通气量控制在4L/min时,搅拌转速达到300r/min即可满足细胞生长和聚γ-谷氨酸合成对溶解氧的需求.不同pH控制方式对聚γ-谷氨酸分批发酵的影响有较大差异.不控制pH时,细胞干重和聚γ-谷氨酸产量比控制pH为5.5的发酵分别低26%和94%.研究了将pH控制在4.0、4.5、5.0、5.5、6.0和6.5的聚γ-谷氨酸分批发酵过程,发现在pH5.5时聚γ-谷氨酸总产量最高.以溶氧水平作为甘油代谢指针来控制甘油限制性流加既可维持一定菌体生长,又不会发生发酵液中残余甘油及有害代谢产物阻遏作用.菌体关于甘油的表观的率、聚γ-谷氨酸的平均比生产速率较没有采用甘油限制性流加时都有所提高.图4表1参7     

Degradation of azo dye Acid Red 14 in aqueous solution by electrokinetic and electrooxidation process

A new wastewater treatment technology--electrokinetic-electrooxidation process (EK-EO process) is developed in this paper. The EK-EO process can take advantage of both electrooxidation on the anode surface and the electrokinetic process of anionic impurities under an electric field, which can enhance the TOC removal in electrolysis process. The degradation of an anionic azo dye Acid Red 14 (AR14) was experimentally investigated. It was found that under an electric field AR14 could be migrated into anode compartment and be efficiently mineralized. After 360 min electrolysis of 100 mgl(-1) AR14 solutions at 4.5 mAcm(-2), complete discoloration was observed in both cathode and anode compartment. About 60% TOC was electromigrated from cathode compartment to anode compartment, and more than 25 mgl(-1) TOC was abated in anode compartment. A possible degradation mechanism of AR14 by EK-EO process was proposed. Additionally, the effect of current density, recycling flux, and electrolyte concentration on the EK-EO degradation of AR14 was also investigated.     

Organo-chlorine pesticide (DDT and HCH) residues in the Taihu Lake Region and its movement in soil-water system I. Field survey of DDT and HCH residues in ecosystem of the region

The use of organo-chlorine (DDT and HCH) has been banned in China for 20 years. A field survey was carried out during 1999-2000 in the Taihu Lake Region. Organo-chlorine pesticide (OCP) residues in soil, water, fish and sediment samples were investigated. DDT was detected in 5 out of 10 samples with concentration ranging from 0.3 to 5.3 microg/kg in the surface (0-15 cm) layer, 6 out of 10 with 0.5 to 4.0 microg/kg in the subsoil layer (16-30 cm), and 4 of 10 with 0 to 2.7 microg/ kg in the deep soil layer (31-50 cm). Results for HCH residues in soil samples were similar to those of DDT. These results indicate that OCP residues in 0-50 cm profile had been leached out or degraded to safe level. In river water DDT was detected in 10 out of 13 samples ranging from 0.2 to 9.3 microg/l, with an average of 1.0 microg/l. While HCH was detected in 12 out of 13 samples ranging from 0.02 to 36.1 microg/l, with an average 5.6 microg/l. DDT residues in sediment ranged from 0.1 to 8.8 microg/kg, while HCH ranged from 0.3 to 66.5 microg/kg. DDT residues in fish body ranged from 3.7 to 23.5 microg/kg and HCH ranged from 3.7 to 132 microg/kg. These results demonstrate an accumulation through food chain (from soil-water-sediment-microbes-crop-fish-... etc.), also that HCH residues are generally more persistent than DDT residues. However, all these data are well below than the state warning standard limit.     

Distribution and relationships of selected trace metals in molluscs and associated sediments from the Gulf of Aden, Yemen

Concentrations of Cd, Pb, Zn, Cu, Ni, Co, Cr, Mn and Fe in the soft tissue of Turbo coronatus, Acanthopleura haddoni, Ostrea cucullata and Pitar sp., as well as in associated surface sediments (bulk and bioavailable metal concentrations) from the Gulf of Aden, Yemen, were determined by atomic absorption spectrophotometry method. Large differences between size-classes of molluscs in metal concentrations were recorded. Significant spatial differences in metal concentrations in both the soft tissue of the molluscs and associated sediments studied were mostly identified. Statistically significant correlations (p<0.01) between concentrations of selected metals were observed. A slope of the linear regression is significantly higher than unity for Fe (9.91) and Cd (3.45) in A. haddoni and for Ni (4.15) in T. coronatus, suggesting that the bioavailability of these metals is disproportionally increased with a degree of enrichment of the sediments in Fe, Cd and Ni, respectively. A slope constant approximating to unity (1.14) for Cu in A. haddoni relative to its concentration in sediment extract implies that bioavailability of this metal proportionally increased with growing concentrations of its labile forms in the associated sediment. The degree of contamination of Gulf of Aden waters by the metals studied is discussed and the potential ability of molluscs, especially A. haddoni and T. coronatus, as biomonitors of metallic pollutants is postulated.     

Trace metal speciation and bioavailability in urban soils

Urban soils often contain concentrations of trace metals that exceed regulatory levels. However, the threat posed by trace metals to human health and the environment is thought to be dependent on their speciation in the soil solution rather than the total concentration. Three inactive railway yards in Montréal, Québec, were sampled to investigate the speciation and bioavailability of Cd, Cu, Ni, Pb and Zn. Soil solutions were obtained by centrifuging saturated soil pastes. In the soil solutions, up to 59% of the dissolved Cd was in its free ionic form. For Cu, Pb and Zn, organic complexes were the predominant species. Over 40% of Ni was present as inorganic complexes if the solution pH exceeded 8.1. Multiple regression analyses showed that pH and total metals in soil were significantly correlated with the activities of free metal ions, except for Cd(2+), which only had a weak correlation with soil pH. Free, dissolved and total soil metals were tested for their ability to predict metal uptake by plants in the field. However, none of these metal pools were satisfactory predictors. The results indicated that in these urban soils, trace metals were mainly in stable forms and bioavailability was extremely low.