南非大象管理与象牙贸易

本文对南非为什么要主张开放象牙贸易进行了分析，从历史上给出了南非大象的管理历程以及目前的实际情况。     

基于图像解译的瑞典山地石南退化早期检测

山地相对于低地,植被脆弱,尤其是在副极地地区,仅具有很低的生产力,恢复力较弱.山地植被对于机械损伤很脆弱,因此需要快而准确的方法监测山地植被,这对于规划资源的可持续利用有着重要意义.本研究的主要目的:①调查山区南部属于海洋性气候的圆丘形冰碛和用于夏季放牧的开阔区域,干燥矮小的石南灌木,是否很容易发生改变;②检验高分辨率IKONOS-2卫星影像是否可以用来对山区植被中的侵蚀斑块进行高精度的检测、定量化和制图;在什么情况下,这些数据可以替代彩色红外航片在变化早期检测中的应用.通过对比2000年的IKONOS-2高分辨率卫星影像打印图像和1975年彩色红外航片的目视解译结果,进行了植被变化的检测,并对解译结果进行了比较和实地验证.结果表明1975～2000年间,侵蚀发生在受风石南(Windheams)附近,这说明圆丘形冰碛地貌条件下,受风石南和矮小的干燥石南(Dry heaths)灌木很容易受到践踏和放牧的机械损伤,因此很容易发生改变.大部分的受风石南和其变化面积都较小(50～1000m2).结果显示对IKONOS-2卫星影像的目视解译,可以检测到侵蚀斑块和受风石南的面积和分布的细微变化,并且有较高的精度.这表明高分辨率卫星影像(4×4m像素分辨率)可以替代彩色红外航片来监测这些变化.     

Seasonality in freerunning circadian rhythms in man

Retrospective analysis of data collected over 15 years in normal subjects isolated from time cures showed seasonal rhythms in the circadian period of the core temperature rhythm, in the amount of sleep (both shorter in spring and longer in autumn), and in the incidence of internal desynchronisation (most often in summer). Women slept longer than men at all times of year.     

Effect of humification processes on polyaromatic hydrocarbons concentration during wastewater treatment.

The aim of the present work was to compare the concentration changes of polyaromatic hydrocarbons (PAH) and the course of humification processes during wastewater treatment. Studies of samples from a biological-mechanical wastewater treatment plant in Sosnowiec-Zagórze (Poland) were carried out. Determination of PAH was performed both for wastewater sludge and sludge water. Observations of the course of humification processes for humic acid fractions isolated from sludges were conducted. Analysis of PAH extracted from wastewaters and from sludge was performed by means of high-performance liquid chromatography. Investigations of humification processes were conducted by electron paramagnetic resonance and nuclear magnetic resonance methods. The elementary composition changes in the structure of the extracted humic acids were determined. It was found that polyaromatic hydrocarbons appear during the processes of humification. Their content in water decreased only after the process of sludge aeration; however, sludge water leaving the settlers was PAH-enriched.     

Assessing the environmental fate of chemicals of emerging concern: a case study of the polybrominated diphenyl ethers

It is suggested that assessments of chemicals of emerging concern can be rationally structured around a multistage process in which fate and risk are evaluated with increasing accuracy as new data become available. An initial tentative and approximate assessment of fate and risk can identify key data gaps and justify and direct further investigations, which progressively improve the reliability of the assessment. This approach is demonstrated for a class of chemicals, the polybrominated diphenyl ethers (PBDEs), which is of increasing concern, but about which there is presently a lack of comprehensive data on properties, sources, fate and effects. Specifically, 20 PBDE congeners are investigated using the suggested approach and research needs are identified.     

Degradation of para-hydroxybenzoic acid by means of mixed microbial cultures

Olive mill wastewater contains some phenolic compounds that cause antibacterial activity of a kind that prevents biological treatment without previous dilution. Among these phenolic compounds, p-hydroxybenzoic acid (PHB) is considered to be one of the most representative. This work examines the biodegradation of PHB by aerobic microbial mixed cultures previously acclimatized to glucose, which was used as an easily biodegradable model compound. Microbial growth runs were carried out in a batch reactor in the PHB concentration range of 200-1000 mg/L. In all the runs the PHB proved to be completely degradable. The specific growth rates obtained were in the range of 0.16-0.35 l/h. Experimental runs showed that the functional relationship between the specific growth rate and PHB concentration was that proposed by Monod. The kinetic constants of the Monod equation (mu(max) and K(S)) and biomass yield coefficient (Y) were determined experimentally. With the parameter values thus obtained, a mathematical model that also takes account of the duration of the lag phase was employed to describe both the microbial growth and the consumption of PHB. The concentration values of the model fit well with the data obtained experimentally.     

Oxalate production by wood-rotting fungi growing in toxic metal-amended medium

In this report, we have identified oxalic acid as an important metabolite elaborated in the response of wood-rotting fungi to toxic metal stress. The formation of oxalate crystals by white rot fungi (Bjerkandera fumosa, Phlebia radiata and Trametes versicolor) and the brown rot fungus Fomitopsis pinicola, grown on media containing high levels of toxic metal ions has been visualized using scanning electron microscopy (SEM) with energy-dispersive X-ray micro-analysis (EDXA) and HPLC. There were no significant differences between the growth of controls (metal-free) and on the 0.5% CaCO(3), Co(3)(PO(4))(2) or Zn(3)(PO(4))(2)-amended plates. ZnO inhibited the growth of all strains. Crystals were not detected in Zn(3)(PO(4))(2)-amended plates. The four examined strains displayed the formation of crystals on ZnO, Co(3)(PO(4))(2) and CaCO(3)-amended plates.     

3D printing filament as a second life of waste plastics—a review

In recent times, the issue of plastic recycling has become one of the leading issues of environmental protection and waste management. Polymer materials have been found an application in many areas of daily life and industry. Along with their extended use, the problem of plastic wastes appeared because, after withdrawal from use, they became persistent and noxious wastes. The possibility of reusing polymeric materials gives a possibility of valorization—a second life—and enables effective waste utilization to obtain consumable products. The 3D printing market is a well-growing sector. Printable filaments can be made from a variety of thermoplastic materials, including those from recycling. This paper focuses on a review of the available literature on the production of filaments for 3D printers from recycled polymers as the alternative to present approach of central selective collection of plastics. The possibility of recycling of basic thermoplastic materials and the impact of processing on their physicochemical and mechanical properties were verified (Lanzotti et al. 2019). In addition, commercially available filaments produced from recycled materials and devices which allow self-production of filaments to 3D printing from plastic waste were reviewed.

     

Polychlorinated dibenzo-p-dioxins and dibenzofurans pollution in China: sources, environmental levels and potential human health impacts

This review represents an assessment of the pollution status of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in China (the mainland, Hong Kong and Taiwan). During the past decades, seven PCDD/Fs pollution hotspots have been found: (a). Ya-er Lake, Hubei Province, with 'total PCDD/Fs' level reaching 177,427 pg g(-1) (dry weight) in lake sediments; (b). Chinese Schistosomiasis affected areas of Jiangxi Province with 33,660 pg g(-1) in soil; (c). e-waste recycling area of Yangtze River Delta, with 2726 pg g(-1) in paddy soil; (d). e-waste recycling area of Guiyu (eastern part of Guangdong Province), with 967,500 pg g(-1) in mixture of burnt residue and soil (the highest level among all hotspots); (e). Pearl River Delta with 2630 pg g(-1) in coastal sediment. (f). Kwun Tong, Victoria Harbour, Hong Kong with 10,999 pg g(-1) in coastal sediment; and (g). southern Taiwan with 606,000 pg g(-1) in soil near the vicinity of a pentachlorophenol manufacturing factory. The main sources of PCDD/Fs in China were formed from impurities during the production of polychlorophenol, hexachlorobenzene, polychlorinated biphenyls, organic chlorinated pesticide and triclosan. In addition, sources of PCDD/Fs included municipal waste incineration, mineral fuel usage, open burning of electronic waste and crop residues, industrial waste discharge and vehicle exhaust emission. Due to potential human health risks from long-term exposure to PCDD/Fs at these hotspots, body loadings of these contaminants should be monitored.