Chronic toxicity of copper on embryo development in Chinese toad, Bufo gargarizans

This study examined the effects of copper exposure on embryonic development of Chinese toad, Bufo gargarizans. Firstly, the LC₅₀ values from 24 to 96 h of exposure were 3.61 × 10⁻⁶ M, by means of a 4 d toxicity test with B. gargarizans embryos. Secondly, Chinese toad embryos were exposed to 10⁻⁹-10⁻⁶ M copper from mid gastrula stage to operculum completion stage. Measurements included mortality, tadpole weight, tadpole total length, growth retardation, duration of different embryo stages and malformation. Embryonic survival was not affected by copper. Relative to control tadpoles, significantly decreased weight and total length were found at 10^-9-10^-6 M reduced percentage of the embryos in right operculum stage after 10 d exposure to copper and reduced percentage of embryos in operculum completion stage after 12 d exposure to copper were also observed. Moreover, the duration of embryonic development increased at neural, circulation and operculum development stage in copper-treated groups. For the scanning microscope and histological observation, the abnormalities were malformation of wavy dorsal fin, flexural tail, curvature body axis, yolk sac oedema and reduced pigmentation in the yolk sac. Histopathological changes in olfactory, retinal epithelium and skin were also observed. DNA strand breaks exposed to the copper were analyzed by DNA ladder. In conclusion, copper induced toxic effects on B. gargarizans embryos. The present study indicated chronic toxicity tests may provide more accurate way in formulating the “safe levels” of heavy metals to amphibian.     

新疆阿尔泰地槽成矿元素分布特征

新疆阿尔泰地槽内成矿元素 ,自北东向南西分为四个带 ,每个带内分布有元素区和矿床 :①阿尔泰山北缘元素带 (阿克萨拉等区 ) ;②阿尔泰山中脊元素带 (冲呼等五个区和可可托海 3号脉稀有金属矿等矿床 ) ;③阿尔泰山南缘元素带 (阿舍勒等四个区和阿舍勒铜矿等矿床 ) ;④额尔齐斯元素带 (喀拉通克等区和喀拉通克铜镍矿等矿床 )。成矿元素区带是寻找新矿床的有利地段     

新疆老山口金矿岩浆隐爆角砾岩地质地球化学

新疆东准噶尔老山口金矿区发育有与金矿化密切有关的次火山闪长玢岩及与之密切伴生的闪长玢岩质隐爆角砾岩和闪斜煌斑岩质隐爆角砾岩 ,它们是在陆相火山作用下由同源岩浆分异演化而形成的产物。角砾岩具有浅成—超浅成环境及热塑、高压释放状态下的成岩特征。角砾岩的角砾、胶结物和次火山岩三者的岩石类型、岩相学特征和地球化学特征基本一致 ,具有稀土总量较低 ,轻稀土相对富集 ,重稀土相对亏损 ,铕异常不明显 ,大离子亲石元素相对富集 ,高场强元素相对亏损等特征。结合其构造背景、地质产状、岩石学和地球化学特征分析 ,这套岩石来源于受俯冲洋壳释放富含大离子亲石元素或强不相容元素流体交代过的亏损地幔楔。     

氮气中二氧化硫气体浓度测量不确定度的评定

采用紫外荧光法测定氮气中的二氧化硫气体浓度的测量不确定度.充分考虑重复测量的重现性、测量仪器的计量性能局限性、标定仪器所用的标准气体等因素对测量的影响,计算氮气中的二氧化硫气体浓度测量合成标准不确定度为0.4.     

废水中有机物生物降解性数据库系统的研究

在全面分析废有机物生物降解性数据库系统的需求状态及特点的基础上,采用软件工程的方法,面向用户完成了该数据系统的系统分析和系统设计,为系统的进一步全面实施奠定了基础。     

细菌降解非离子表面活性剂的研究

从石油污染的土壤中分离到２株能利用非离子表面活性剂ＡＥＯ－９和ＳＡ－２０作为唯一碳源生长的细菌。这２株菌被定名为假单胞杆菌５２（Ｐｓｅｕｄｏｍｏｎｏｓ５２）和Ｗｅｅｋｓｅｌｌａ６．最适于这２株菌利用非离子表活剂ＡＥＯ－９的培养条件是乙酸胺作为氮源,ｐＨ７．３０℃添加少量葡萄糖促进表活性的降解,降解速率的研究表明,当ＡＥＯ－９的初始浓度为５０００ｍｇ／Ｌ时,５２号菌和６号菌能在２周内将其去除８５％,     

序列间歇式活性污泥法处理毛纺厂废水的研究

采用序列间歇式活性污泥法处理毛纺厂废水。试验结果表明,经4h曝气处理,进水COD为190～650mg/L时,出水COD始终低于100mg/L,去除率大多在80％～90％之间,色度去除率大多在50％以上,出水COD和色度均达到行业排放标准。还对较低COD浓度下序列间歇式活性污泥法的COD降解过程进行了研究,推导出一级反应动力学关系式Sr＝So（1－10￣^-k1^t）,并以试验数据进行了拟合,求解出动力学常数k1和So。     

环境影响综合评价灰色层次模型研究

针对水电工程环境影响综合评价问题，应用拓展的灰关联理论和最小二乘准则，建立了环境影响综合评价的灰色层次模型。以东江水电工程环境影响综合评价为实例说明了该模型的合理性、可信性。结果表明：此基工程使环境总体向理想的１８．１％     

Daily Bank Erosion Rates in the Lower Yellow River Before and After Dam Construction

During the period of water impoundment and sediment detention of the Sanmenxia Reservoir, riverbank erosion processes played a key role in the channel evolution of the Lower Yellow River (LYR). However, research into bank erosion rates of the LYR has been neglected due to the lack of direct field monitoring. In this study, an indirect method is proposed to determine bank erosion rates at daily time scales by outlining a detailed calculation procedure using measured hydrological data. A total of 810 data points of daily bank erosion rates before and after the construction of Sanmenxia Dam was calculated at seven hydrometric sections along the LYR, with the corresponding values of the bank stability coefficient and the width‐to‐depth ratio also being calculated. Empirical relations were then developed to estimate the daily bank erosion rates, using these parameters at the sections. Temporal and spatial variability in daily bank erosion rates in the LYR before and after dam construction were also investigated, revealing that: (1) the bank erosion rates had a mean value of 16.7‐29.1 m/day in the braided reach, with a maximum value of 290.0 m/day, while they were relatively low in the meandering reach, with a mean value of 2.5 m/day; (2) the erosion rates before dam construction were slightly greater than those after dam construction, with the difference reaching 5‐10 m/day in the braided reach, decreasing in the transitional reach gradually, and being slight in the meandering reach.     

Sorption of phthalate acid esters on black carbon from different sources

Black carbon (BC) is known as a strong sorbent for the sorption of planar hydrophobic organic compounds (HOCs), but there is very little information about the sorption of nonplanar HOCs on BC. In this study, the sorption of di-(2-ethyl-hexyl) phthalate (DEHP), one kind of nonplanar phthalate acid ester (PAE), by environmental BC collected from river sediments and pure BC (char-wood, char-stalk and soot-ash) was investigated. Strong and nonlinear sorption was observed for the sorption of DEHP on both pure BC and environmental BC with the Freundlich exponent ranging from 0.55 to 0.75 except for soot-ash, and the measured K(BC) (BC-water partition coefficient) of DEHP was about one order of magnitude higher than its organic carbon-water partition coefficient. There was a significant difference in sorption capacity among the environmental and pure BC. The presence of di-methyl phthalate (DMP) could significantly decrease the sorption of DEHP on BC, especially for environmental BC. In addition, the contribution of BC to the total sorption of DEHP on original river sediments was more than 50% when the equilibrium concentration of DEHP was less than 10 μg L(-1). This study indicated that ortho-substituted nonplanar PAEs could also be strongly sorbed by BC, and the difference in sorption among the BC samples revealed that it is important to take the source of BC into account when assessing its effects on the fate of HOCs in aquatic environment.