Sources of pollution and distribution of Pb,Cd and Hg in Wrocław soils: Insight from chemical and Pb isotope composition

Human activities in cities affect properties of urban soils. In particular, urban soils often contain high contents of harmful metals even in deeper horizons added to them from diverse sources over centuries of the city development. This is reflected in complex distribution of metals in bulk soils with depth and the complex metal fractionation, but the exact sources of the metals are difficult to identify. This is also the situation in soils from Wroclaw, one of the largest cities in Poland. Potentially harmful elements Pb, Cd and Hg were examined in six profiles located along the major communication route and compared to two non-urban soils profiles located close to the same route. In all of the urban profiles, Pb and Cd exceeded the element contents observed in non-urban profiles and showed an erratic distribution compared to the more predictable one in non-urban soils. The differences between urban and non-urban profiles were explained as the result of contamination coming from more pollution sources in the case of urban soils, the conclusion supported by Pb isotope analyses. In fact, Pb isotopes showed that the contamination sources in urban soils included leaded petrol, coal combustion, smelting and possibly old pre-industrial ore processing, whereas leaded petrol and pre-industrial lead were the only possible anthropogenic sources in non-urban soils. The comparison of Wrocöaw soils with those from cities of comparable size Kraków and Poznań show similar ranges of metal contents with implication that urban pollution oversteps diverse geogenic chemical background. On the other hand, the comparison with other European cities show large variability in metal contents and suggest that urban soils contamination is time integrated and reflects long-term industrial evolution of each country.     

长江—黄河上游源区沼泽湿地遥感动态特征及其成因分析

通过两个时像的对比解译、调查验证和研究,表明长江-黄河上游源区20世纪90年代初至21世纪初的10年中,沼泽湿地总体呈减少趋势。由于自然和人为综合因素的长期作用,使本区沼泽湿地处于萎缩状态。     

新疆地震台网超短波传输系统及故障分析

介绍了新疆地震台网子台供电系统中太阳能电池、太阳能充电控制器、免维护蓄电池以及稳压电源等主要设备和超短波数传系统中发射机、接收机、数字复、分接设备以及天线等设备的日常维护,对超短波数传的原理、场强的接收以及设备的一些参数,作了简单的阐述,对台站设备日常出现的问题和故障,作了简单分析,并给出了一些解决的办法。并就1次典型的台网故障现象分析及排除作了详尽的阐述。     

Adjoint method for the optimum planning of industrial pollutant sources

The deterioration of air quality is threatening the life and health of people. Scientists in China and other countries have done a great deal of research work on the details of air pollution and the methods of preven-tion and control during the past decades. Up to now, most of the achievements are concentrated on the techniques of controlling pollutant sources and the programs of reduction, which focus on the improve-ment of air quality and the restoration of environment. The techniques of con…     

中国硫的供求现状和展望

从工业和农业两个方面供需现状分析，中国目前硫的供需基本平衡，且供略大于求。展望２０００年，中国硫的供求关系将出现缺口，需进一步开拓硫的潜在资源。从总体上看，目前中国土壤供硫情况尚好，但一些地区已开始出现缺硫和严重缺硫的状况，预测今后土壤缺硫状况将会加剧，希望各有关部门对此应给予充分注意     

北京平原区水源热泵应用适宜区划分

北京市水源热泵的应用,宏观上未充分考虑地下水水源地的分布,微观上未注重应用场地的水文地质条件,地下水回灌率低造成了水资源浪费。本文针对北京平原区的水文地质条件,以浅层含水层导水系数、有效导水系数、地下水中的铁和总硬度为评价因子,以水源地保护区及补给区、地面沉降中心区为约束因子,利用叠加分析技术,将平原区分为适宜发展区、较适宜发展区、限制发展区和禁止发展区,为水源热泵的理性推广提供了技术参考。     

Polybrominated diphenyl ethers and polychlorinated biphenyls in sediments of southwest Taiwan: regional characteristics and potential sources

Very little information is available on the contamination of coastal sediments of Taiwan by PBDEs and PCBs. In this study, we determined the concentrations of 19 PBDE and 209 PCB congeners in 57 surface sediment samples to identify the possible sources of PBDEs and PCBs. The total PBDE and PCB concentrations ranged from below detection limit to 7.73 ng/g and 0.88-7.13 ng/g, respectively; these values are within the ranges observed for most coastal sediments worldwide. The PBDE congeners were dominated by BDE-209 (50.7-99.7%), with minor contributions from penta- and octa-BDEs. The signatures of PCB congeners suggested that PCB residues in Kaohsiung coast may be the legacy of past use or the result of ongoing inputs from the maintenance, repair and salvage of old ships. Principal component analysis of the congener-specific composition of PBDEs and PCBs revealed distinct regional patterns that are related to the use of commercial products.     

三江源地区水资源的涵养和保护

分析了三江源区水资源现状,论述了建立水资源三级保护区的意义、作用和划分方案,实施林草植被的保护和恢复的水文生态效益及健全水资源补偿机制的必要性。