Effects of urbanization on heavy metal accumulation in surface soils, Beijing

Urbanization processes affect the accumulation of heavy metals in urban soils. Effects of urbanization on heavy metal accumulation in soils were studied using Beijing as an example. It has been suggested that the ecological function of vegetation covers shifting from natural to agricultural settings and then to urban greenbelts could increase the zinc(Zn) concentrations of soils successively. The Zn concentration of urban soils was significantly correlated to the percentage of the impervious land surface at the500 m × 500 m spatial scale. For urban parks, the age or years since the development accounted for 80% of the variances of cadmium(Cd) and Zn in soils. The population density,however, did not affect the heavy metal distributions in urban soils. To conclude, the urban age turned out to be a notable factor in quantifying heavy metal accumulation in urban soils.     

Determination of Background Concentrations of Inorganics in Soils and Sediments at Hazardous Waste Sites

Hazardous waste sites may pose a threat to human health and the environment when toxic substances are released. However, the contaminants present at a waste site may have originated on-site (i.e., resulting from releases attributable to site activities) or off-site (i.e., resulting from sources not on-site). Off-site substances may result either from natural sources (e.g., erosion of naturally occurring mineral deposits) or anthropogenic sources (e.g., widespread contamination from automobile exhaust in urban areas). To determine the appropriate action to take at a hazardous waste site, the U.S. Environmental Protection Agency (EPA) must distinguish between substances directly attributable to the hazardous waste site (i.e., site contaminants) and those attributable to natural background concentrations. The most important factor to consider when determining background concentrations is to ensure that the physical, chemical, and biological aspects of the media to be sampled at both the contaminated site and the background site are as similar as possible. Inorganics, in particular metals, are addressed. Radionuclides are not specifically addressed; however, metals with radioactive isotopes that may be encountered at hazardous waste sites are included. There are references and data included in this paper that provide average concentrations and reference values for selected soils and sediments in the United States. Suggested sampling and monitoring design approaches that could be used by scientists and engineers faced with how to determine background concentrations are identified. The issues discussed include the selection of background sampling locations, considerations in the selection of sampling procedures, and statistical analyses for determining whether contaminant levels are significantly different on a potential waste site compared with a background site.     

Sorption of mercury (II) in Amazon soils from column studies

The sorption of Hg (II) onto four different types of Amazon soils from the A-horizon was investigated by means of column experiments under saturation conditions and controlled metal load. Higher organic matter contents in the soil resulted in higher Hg (II) adsorptions, reaching values as high as 3.8 mg Hg g⁻¹ soil. The amount of mercury adsorbed on a soil column (Q) shows a very poor correlation with soil clay content (r² = 0.2527), indicating that Hg sorption in these topsoil samples is chiefly governed by the organic matter content. Desorption experiments using Negro River (Amazon) waters were conducted using soil saturated with Hg (II) in order to better understand the metal leaching mechanism. The amount of Hg (II) released from soils was around 30% of the total sorbed mercury upon saturation, suggesting that mercury sorption in the soils present in the catchment area of the Negro River basin is not a reversible process.     

An empirical map of critical loads of acidity for soils in Great Britain

The method used to produce a critical load map of acidity for soils in Great Britain is described. Critical loads were assigned to the dominant soil in each 1 km grid square of the UK national grid. Mineral soils were assigned a critical load based on mineralogy and chemistry, using approaches appropriate to UK conditions. Critical loads for peat soils are based primarily on a maximum acceptable reduction of peat pH, and results from laboratory equilibration studies. The map shows that soils with small critical loads (<0.5 kmol_c ha⁻¹ year⁻¹) i.e. highly sensitive to acidic deposition, dominate in the north and west of Britain; the south and east are dominated by soils with large critical loads, with small areas of more sensitive soils associated with sandy soil-forming materials. A modified critical load map illustrates the potential impact of agricultural liming on soil critical loads.     

Effect of expandable clays and cometabolism on PAH biodegradability

Pyrene and phenanthrene degradation was examined in both single and binary slurry systems for three different natural soils. It was found that the amount of total expandable clays (smectite and vermiculite) was in a good agreement with the achieved rate and extent of biodegradation. For instance, the intrinsic phenanthrene biodegradation rate was 626 microg/L/day for the soil with the largest expandable clay and 3203 microg/L/day for the soil with the least. Similarly, the smallest total pyrene biodegradation (65%) was found for the soil rich in expandable clays, compared to an 82% pyrene reduction in the soil that had the lowest amount. Mass transfer limitation after compound sorption to the clays was more pronounced for the more hydrophobic pyrene. In the presence of phenanthrene, total pyrene biodegradation increased by 2 to 7% due to cometabolism, while the total phenanthrene biodegradation was only enhanced by 0.5 to 5% in the binary system. This research demonstrated that expandable clays might govern the substrate availability to microorganisms and microbial accessibility to substrates. Therefore, the contribution of organic matter and expandable clays to sorption, desorption and biodegradation should be taken equally into account in order to better understand complex bioremediation issues.     

坚持科学发展观,大力推进循环经济建设--关于东部工业区改造、建设生态工业园区的几点思考

坚持科学发展观,大力推进循环经济建设是我国当前和今后相当长一段时期的主旋律.从秦皇岛市东部工业区的区位优势和资源优势分析出发,提出了将该区改造和建设成生态工业园区的必要性和可能性,在次基础上初步探讨了发展与建设的基本方向与框架.     

IMPACTS OF RECREATION ON RIPARIAN SOILS AND VEGETATION1

ABSTRACT: The seemingly magnetic attraction of water resources for recreation has direct implications for proximate land resources which are needed to provide access and support facilities. This paper reviews and synthesizes the literature dealing with the impacts of recreation use on riparian soils and vegetation. Part one of the paper sets forth the major negative impacts of recreation use on soils and vegetation. A seven-step soil impact cycle is identified, beginning with the scuffing away of leaf litter and other organic material and working through the soil erosion and sedimentation process. Four major kinds of impacts of recreation use on vegetation are then outlined, and the‘Vicious circle” relationship between impacts on soil and vegetation is demonstrated through a Soil/Vegetation Impact Diagram. Part two identifies several spatial and temporal patterns of environmental impact caused by recreation use. The node and linkage pattern of recreation use, campground and trail expansion, ground cover response and succession, rates of soil compaction, and resource response to various intensities of recreation use are important aspects. The final part of the paper deals with measuring environmental impacts caused by recreation use. Management implications of the research findings are considered throughout the paper.     

建设生态工业园区 推进环保产业发展——在南海国家生态工业示范园区暨华南环保科技产业园建设规划论证会上的讲话

论述了建设生态工业园区是实现区域可持续发展、经济和环境双赢的重要举措。     

Sensitivity of soils to acid rain in South China

This paper deals with the sensitivity of soils to acid rain in 5 provinces, South China. Based on field work and literature, and taking soil pH, CEC, and the types of residua into account, the authors classified the sensitivity into 4 categories: highly sensitive, sensitive, slightly sensitive, and non-sensitive. By overlapping the maps of soil pH, CEC, and types of residua, the map of soil sensitivity in South China has finally resulted.The authors try to summarize the regularity of soil sensitivity to acid rain in this area. The sensitivity of different soil types in the studied area has also discussed.The seriousness and its prospects of acid rain in this area have been pointed out in order to draw the attention of relevant authorities.     

城市园林植保污染与环境保护控制对策

就城市园林植物保护对生态环境造成的污染,结合园林植物及病虫害的生态特点,从环境保护的角度,提出综合的防控措施和环境保护对策建议,使园林植保和环境保护工作相得益彰。