高邮市基本农田环境质量监测与评价

根据近两年高邮市试点工作经验，介绍基本农田分等定级的环境监测与评价方法，认为积极开展农田环境监测并进行科学评价是基本农田保护的重要工作内容。     

炼油装置运行周期评估技术及应用

炼油装置运行周期评估技术通过统计、分析装置故障数据,计算特定时间段装置的可靠性,进而获得装置可靠性随时间的变化规律和装置可靠性最差设备排序。介绍了该技术在某常减压装置的应用,应用结果表明,该评估技术为科学确定炼油装置运行周期提供了决策依据。     

The effectiveness and risk comparison of EDTA with EGTA in enhancing Cd phytoextraction by Mirabilis jalapa L.

In the previous study, Mirabilis jalapa L. had revealed the basic Cd hyperaccumulator characteristics, but the accumulation ability was not as strong as that of other known Cd hyperaccumulators. In order to improve the accumulation ability of this ornamental plant, the chelants were used to activate the Cd in soil. As a substitute, ethylene glycol bis(2-aminoethyl) tetraacetic acid (EGTA) was selected to testify whether it has better effectiveness and can bring lesser metal leaching risk than EDTA. The data showed that the growth of M. jalapa was inhibited, while the Cd concentration of the plant was significantly increased under the treatments containing EDTA or EGTA. The Cd translocation ability under the EGTA treatments was higher than that under the EDTA treatments. The available Cd resulted from the application of chelant EGTA to the contaminated soils can be limited to the top 5 cm, while the application of chelant EDTA to the contaminated soils can be limited to the top 10 cm. In a word, EGTA showed better effectiveness than EDTA in enhancing Cd phytoextraction of M. jalapa. As an ornamental plant, M. jalapa has the potential to be used for phytoextraction of Cd-contaminated soils and it can beautify the environment at the same time.     

Nitrogen enrichment in runoff sediments as affected by soil texture in Beijing mountain area

Enrichment ratio (ER) is widely used in nonpoint source pollution models to estimate the nutrient loss associated with soil erosion. The objective of this study was to determine the ER of total nitrogen (ER_N) in the sediments eroded from the typical soils with varying soil textures in Beijing mountain area. Each of the four soils was packed into a 40 by 30 by 15 cm soil pan and received 40-min simulated rainfalls at the intensity of 90 mm h^?1 on five slopes. ER_N for most sediments were above unity, indicating the common occurrence of nitrogen enrichment accompanied with soil erosion in Beijing mountain area. Soil texture was not the only factor that influenced N enrichment in this experiment since the ER_N for the two fine-textured soils were not always lower. Soil properties such as soil structure might exert a more important influence in some circumstances. The selective erosion of clay particles was the main reason for N enrichment, as implied by the significant positive correlation between the ER of total nitrogen and clay fraction in eroded sediments. Significant regression equations between ER_N and sediment yield were obtained for two pairs of soils, which were artificially categorized by soil texture. The one for fine-textured soils had greater intercept and more negative slope. Thus, the initially higher ER_N would be lower than that for the other two soils with coarser texture once the sediment yield exceeded 629 kg ha^?1.     

Assessing the effects of severe rainstorm-induced mixing on a subtropical,subalpine lake

Severe rainstorms cause vertical mixing that modifies the internal dynamics (e.g., internal seiche, thermal structure, and velocity filed) in warm polymictic lakes. Yuan Yang Lake (YYL), a subtropical, subalpine, and seasonally stratified small lake in the north-central region of Taiwan, is normally affected by typhoons accompanied with strong wind and heavy rainfall during the summer and fall. In this study, we used the field data, statistical analysis, spectral analysis, and numerical modeling to investigate severe rainstorm-induced mixing in the lake. Statistical determination of the key meteorological and environmental conditions underlying the observed vertical mixing suggests that the vertical mixing, caused by heat loss during severe rainstorms, was likely larger than wind-induced mixing and that high inflow discharge strongly increased heat loss through advection heat. Spectral analysis revealed that internal seiches at the basin scale occurred under non-rainstorm meteorological conditions and that the internal seiches under the rainstorm were modified on the increase of the internal seiche frequencies. Based upon observed frequencies of the internal seiches, a two-dimensional model was simulated and then appropriate velocity patterns of the internal seiches were determined under non-rainstorm conditions. Moreover, the model implemented with inflow boundary condition was conducted for rainstorm events. The model results showed that the severe rainstorms promoted thermal destratification and changed vertical circulation of the basin-scale, internal seiche motion into riverine flow.     

Assessment of trace element contamination in sediment cores from the Pearl River and estuary,South China: geochemical and multivariate analysis approaches

Twenty-four major and trace elements and the mineralogical composition of four sediment cores along the Pearl River and estuary were analyzed using ICP-AES, ICP-MS, and X-ray diffraction (XRD) to evaluate contamination levels. The dominant minerals were quartz, kaolinite, and illite, followed by montmorillonite and feldspars, while small amounts of halite and calcite were also observed in a few samples. Cluster analysis (CA) and principal component analysis (PCA) were performed to identify the element sources. The highest metal concentrations were found at Huangpu, primarily due to wastewater treatment plant discharge and/or the surreptitious dumping of sludge, and these data differed from those of other sources. Excluding the data from Huangpu, the PCA showed that most elements could be considered as lithogenic; few elements are the combination of lithogenic and anthropogenic sources. An antagonistic relationship between the anthropogenic source metals (K, Ba, Zn, Pb, Cd, Ag, Tl, and U) and marine source metals (Na, Mg, Ti, V, and Ca) was observed. The resulting normalized Al enrichment factor (EF) indicated very high or significant pollution of Cd, Ag, Cu, Zn, Mo, and Pb at Huangpu, which may cause serious environmental effects. Conflicting results between the PCA and EF can be attributed to the background values used, indicating that background values must be selected carefully.     

Heavy metal pollution in surface soils of Pearl River Delta,China

Heavy metal pollution is an increasing environmental problem in Chinese regions undergoing rapid economic and industrial development, such as the Pearl River Delta (PRD), southern China. We determined heavy metal concentrations in surface soils from the PRD. The soils were polluted with heavy metals, as defined by the Chinese soil quality standard grade II criteria. The degree of pollution decreased in the order Cd?>?Cu?>?Ni?>?Zn?>?As?>?Cr?>?Hg?>?Pb. The degree of heavy metal pollution by land use decreased in the order waste treatment plants (WP)?>?urban land (UL)?>?manufacturing industries (MI)?>?agricultural land (AL)?>?woodland (WL)?>?water sources (WS). Pollution with some of the metals, including Cd, Cu, Ni, and Zn, was attributed to the recent rapid development of the electronics and electroplating industries. Cd, Hg, and Pb (especially Cd) pose high potential ecological risks in all of the zones studied. The soils posing significantly high and high potential ecological risks from Cd covered 73.3 % of UL, 50 % of MI and WP land, and 48.5 % of AL. The potential ecological risks from heavy metals by land use decreased in the order UL?>?MI?>?AL?>?WP?>?WL?>?WS. The control of Cd, Hg, and Pb should be prioritized in the PRD, and emissions in wastewater, residue, and gas discharges from the electronics and electroplating industry should be decreased urgently. The use of chemical fertilizers and pesticides should also be decreased.     

Improving artificial forest biomass estimates using afforestation age information from time series Landsat stacks

China maintains the largest artificial forest area in the world. Studying the dynamic variation of forest biomass and carbon stock is important to the sustainable use of forest resources and understanding of the artificial forest carbon budget in China. In this study, we investigated the potential of Landsat time series stacks for aboveground biomass (AGB) estimation in Yulin District, a key region of the Three-North Shelter region of China. Firstly, the afforestation age was successfully retrieved from the Landsat time series stacks in the last 40 years (from 1974 to 2013) and shown to be consistent with the surveyed tree ages, with a root-mean-square error (RMSE) value of 4.32 years and a determination coefficient (R ²) of 0.824. Then, the AGB regression models were successfully developed by integrating vegetation indices and tree age. The simple ratio vegetation index (SR) is the best candidate of the commonly used vegetation indices for estimating forest AGB, and the forest AGB model was significantly improved using the combination of SR and tree age, with R ² values from 0.50 to 0.727. Finally, the forest AGB images were mapped at eight epochs from 1985 to 2013 using SR and afforestation age. The total forest AGB in seven counties of Yulin District increased by 20.8 G kg, from 5.8 G kg in 1986 to 26.6 G kg in 2013, a total increase of 360 %. For the persistent forest area since 1974, the forest AGB density increased from 15.72 t/ha in 1986 to 44.53 t/ha in 2013, with an annual rate of about 0.98 t/ha. For the artificial forest planted after 1974, the AGB density increased about 1.03 t/ha a year from 1974 to 2013. The results present a noticeable carbon increment for the planted artificial forest in Yulin District over the last four decades.     

双极不对称预荷电静电增强过滤除尘技术的应用

双极不对称预荷电静电增强过滤除尘技术 ,是国家“九五”科技攻关课题所取得的成果之一 ,该技术采用双极不对称荷电增强方式 ,将普通静电增强效果与粉尘凝并机能有机地结合在一起 ,既提高了过滤除尘器的收尘效率 ,尤其是呼吸性粉尘的效率 ,同时又极大地改善了滤料粉尘层的结构 ,可显著地降低过滤阻力增值 ,节约运行能耗。笔者研究的该技术应用于焊接车间的焊接烟尘的治理上 ,取得了良好的效果。现场测试表明 ,该技术对焊接烟尘的滤除效率提高了 3% ,尤其对微细粉尘效果显著 ,2 μm粉尘穿透率相对下降了 4 7%。采用超细滑石粉高粉尘负荷测试结果表明 ,过滤阻力增值降低达 30 % ,清灰效果明显改善     

金川公司二矿区通风系统风流非定常流动规律研究

实际上 ,矿井的风流状态受多种因素影响 ,金川公司二矿区井下风流就处于非定常状态 ,为了保证生产安全 ,控制风流状态 ,采取相应的通风措施 ,开设课题研究 ,建立了井巷内空气非定常流动能量方程和通风网络中非定常流动的数学模型。根据该模型可以模拟出矿井通风系统内非定常状态下任意时刻、任意位置通过风量。通过对金川公司二矿区井下机站风机开停和风门开关引起通风系统风流的非定常流动过程的数值模拟 ,得出了受其影响区域内风流状态的变化规律 ,并为其采取通风措施和控制风流状态 ,提供了科学依据