南亚热带丘陵土壤水分循环及其有效性的研究──Ⅰ.赤红壤水库容及其有效性

阐述了南亚热带低山、丘陵、台地赤红壤总库容、贮水库容、通透库容的占有情况。探讨了水库容的有效性以及不同利用方式的赤红壤有效水库容与无效水库容的差异,并对影响赤红壤水分有效性的因素作了分析．结果表明：赤红壤贮水库容小,尤其是有效水库容小;赤红壤水分有效性主要与土壤有机质相关。     

南亚热带丘陵土壤水分循环及其有效性的研究──Ⅳ.丘陵土壤贮水量的增减规律

根据三年定位实测资料,阐述0～100cm土层贮水量的动态变化,分析土壤贮水增减与降雨、蒸发的关系．观测结果表明,在气候正常年,雨季土壤贮水为增量,旱季土壤贮水为减量,但在坡地不同坡段和梯地不同梯级,土壤贮水增减有差异。在旱月土壤贮水减至最低,仅相当子田间持水量的55％～80％．因此在土壤水分管理上．应当密切注意土壤贮水减量最大的时期,以采取有效措施减少土壤水分蒸发,提高土壤水分利用率。     

南亚热带丘陵土壤水分循环及其有效性的研究──Ⅵ.丘陵赤红壤-果树-大气连续体中能量的变化及其分布规律

依据田间实测资料,分析了南亚热带丘陵赤红壤-果树-大气连续体中的能量变化及其分布规律、结果表明,土壤基质势的年度变化特征说明南亚热带丘陵赤红壤存在明显的湿季和旱季．果树叶水势随土壤基质势、大气水势、气温及大气相对湿度的变化而变化,荔枝、龙眼叶水势的变化比芒果叶水势的变化大.以荔枝、芒果和龙眼作为供试植物,水分从土壤到达植物根表皮、进入根系并通过植物茎到达叶片,其能量降低分别约为0．9063～1.7428、0．2818～0．6979和0．2904～1．8707MPa;水分从叶部汽化扩散到大气中,其能量降低分别达15．1491～57．3669、15．4491～58．4036和14．5824～56．9536MPa,说明水流在南亚热带丘陵赤红壤-果树-大气连续体中运移时,其能量主要消耗在由叶部到大气这一环节上。     

南亚热带丘陵土壤水分循环及其有效性的研究──Ⅷ.丘陵赤红壤水分循环与平衡数学模型

依据田间实测资料,在分析丘陵赤红壤水分性质的基础上,建立了土壤有效含水量与土壤物理粘粒含量之间的数学模型、土壤水分特征曲线数学模型、土壤月均贮水量与月降雨总量之间的数学模型和径流率与土壤表层初始含水量之间的数学模型,研究了土壤水分循环与平衡数学模型及各分量与参数的确定方法.     

坡地赤红壤物理退化及其机理研究──Ⅲ.土壤物理退化机理分析

主要通过相关统计和综合分析,探讨坡地赤红壤物理退化的内部和外部环境的影响因素．指出养分贫瘠化,尤其是贫有机质化是坡地赤红壤物理性状退化的主要内部原因,植被破坏则是坡地赤红壤物理性状退化的外部因素、而人类活动的影响对坡地赤红壤的物理退化有重要作用。     

Land desertification monitoring and assessment in Yulin of Northwest China using remote sensing and geographic information systems (GIS)

The objective of this study is to develop techniques for assessing and analysing land desertification in Yulin of Northwest China, as a typical monitoring region through the use of remotely sensed data and geographic information systems (GIS). The methodology included the use of Landsat TM data from 1987, 1996 and 2006, supplemented by aerial photos in 1960, topographic maps, field work and use of other existing data. From this, land cover, the Normalised Difference Vegetation Index (NDVI), farmland, woodland and grassland maps at 1:100,000 were prepared for land desertification monitoring in the area. In the study, all data was entered into a GIS using ILWIS software to perform land desertification monitoring. The results indicate that land desertification in the area has been developing rapidly during the past 40 years. Although land desertification has to some extent been controlled in the area by planting grasses and trees, the issue of land desertification is still serious. The study also demonstrates an example of why the integration of remote sensing with GIS is critical for the monitoring of environmental changes in arid and semi-arid regions, e.g. in land desertification monitoring in the Yulin pilot area. However, land desertification monitoring using remote sensing and GIS still needs to be continued and also refined for the purpose of long-term monitoring and the management of fragile ecosystems in the area.     

Investigation of organic pollutants in wastewater-irrigated soil and its DNA damage and oxidative damage on mice

This work aimed to determine the DNA and oxidative damage on mice by mixtures of organic contaminants in wastewater-irrigated soil, in order to assess their usefulness as markers for this kind of pollution. Wastewater-irrigated soil samples in the vicinity of an industrial area in Tangshan, China were collected, and soil irrigated by underground water satisfying drinking water standards was used as control group. Organic pollutants were extracted from the soil using ultrasonic oscillation, and analyzed by gas chromatography–mass spectrometry (GC-MS). Meanwhile, DNA damage on mice was determined by the Comet assay after oral gavage with the extracts, and changes in total superoxide dismutase (T-SOD) activity, glutathione peroxidase glutathione, GSH peroxidase (GSH-P_X) activity and malondialdehyde content in serum of mice were investigated. The number of categories and concentrations of organic compounds in the wastewater-irrigated soil is more than those in groundwater-irrigated soil, as identified by the GC-MS. The toxicity test of mice showed that compared with reagent control group, the activities of T-SOD and GSH-P_X decreased; the tailing rate of peripheral blood lymphocyte of mice increased and was more than that of the control group. This shows that mammalian toxicity end points can be used to determine the joint toxicity of organic pollutants in soil. When there is no means to identify each and every pollutant in soil, it is feasible to evaluate the combined effects of various pollutants to determine the extent to which the soil is polluted.     

臭氧前体物排放清单相关模型及应用

欧美等国家对于O_3污染的研究开展较早,已建立较成熟的O_3污染生成、扩散及空气质量等模型。文章主要介绍评述了美国环保局推荐使用的计算O_3前体物的相关模型(MOVES、NONROAD、SMOKE、EMFAC和EDMS),从基本原理和功能、污染源类型、研究尺度、所需参数等方面对比分析各模型的特点和适用范围,并综述其国内外研究应用情况;讨论了中国在这些模型的使用方面应该注意的问题,如加强开展模型计算结果验证和基础实验获得本土化的模型参数,以及中国开发的相关模型的优势和适用性等。     

Identification of sources of elevated concentrations of polycyclic aromatic hydrocarbons in an industrial area in Tianjin, China

The concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) were determined by gas chromatography equipped with a mass spectrometry detector in 105 topsoil samples from an industrial area around Bohai Bay, Tianjin in the North of China. Results demonstrated that concentrations of PAHs in 104 soil samples from this area ranged from 68.7 to 5,590 ng g^???1 dry weight with a mean of ∑16PAHs 814 ± 813 ng g^???1, which suggests that there exists mid to high levels of PAH contamination. The concentration of ∑16PAHs in one soil sample from Tianjin Port was exceptionally high (48,700 ng g^???1). Ninety-three of the 105 soil samples were considered to be contaminated with PAHs (>200 ng g^???1), and 25 were heavily polluted (>1,000 ng g^???1). The sites with high PAHs concentration are mainly distributed around chemical industry parks and near highways. Two low molecular weight PAHs, naphthalene and phenanthrene, were the dominant components in the soil samples, which accounted for 22.1% and 10.7% of the ∑16PAHs concentration, respectively. According to the observed molecular indices, house heating in winter, straw stalk combustion in open areas after harvest, and petroleum input were common sources of PAHs in this area, while factory discharge and vehicle exhaust were the major sources around chemical industrial parks and near highways. Biological processes were probably another main source of low molecular weight PAHs.     

Risk assessment of trace elements in cultured freshwater fishes from Jiangxi province,China

The levels of trace elements (As, Cd, Cr, Cu, Fe, Ni, Pb, Se, and Zn) in eight species of cultured freshwater fishes from Jiangxi province were determined by inductively coupled plasma-mass spectroscopy. All the studied trace element levels in fish muscles from Jiangxi province did not exceed Chinese national standard and European Union standard, and they were often lower than previous studies. The calculated target hazard quotient values for all the studied trace elements in fish samples were much less than 1, suggesting that the studied trace elements in fish muscles from Jiangxi province had not pose obvious health hazards to consumers. As and Cd concentrations in northern snakehead were much higher than that in other fishes, demonstrating that this fish species could be valuable as a bioindicator of As and Cd in environmental surveys. In addition, the highest concentrations of Fe, Zn, and moderate contents of other essential trace elements in crucian carp indicated that crucian carp could be a good nutrient source of essential trace elements for human health.