长江口水体中重金属形态交换过程的研究

研究了重金属在水体中溶解态和颗粒态的含量分布,并以一个代表性水平剖面和垂直剖面分析了金属形态交换过程。其动态交换是,重金属由颗粒态沿水平方向交换时向溶解态转化,形态转化强度为Ｎｉ〉Ｆｅ〉Ｃｏ〉Ｃｕ〉Ｍｎ〉Ｐｂ;重金属的垂向交换过程,都是被铁锰（水合）氧化物及有机质吸附,向金属铁锰氧化物态转化,形态转化强度为Ｐｂ〉Ｃｕ〉Ｍｎ〉Ｆｅ〉Ｎｉ〉Ｃｏ,最后得出长江口海域金属污染程度及环境现状。     

铁铝盐基离子对土壤中水溶性氟环境效应的影响

氧化物或粘土矿物可吸附氟离子,但磷酸根离子与氟离子存在竞争吸附效应,造成氟的环境存在量、存在形态及生物效应更加复杂,影响了环境中氟污染的治理.试验选用典型贵州黄壤和石灰土,通过向模拟高氟污染土壤中添加铁铝盐基离子和磷酸盐,采用两因素最优设计,研究外源物质对土壤中水溶性氟的影响.结果表明,FeCl3·6H2O或AlCl3·6H2O都能降低土壤中水溶性氟,而KH2PO4使土壤中水溶性氟增加,对黄壤和石灰土中水溶性氟影响效果大小依次为FeCl3·6H2O(AlCl3·6H2O)、KH2PO4.同时表明,采用铁铝盐基离子改变黄壤性质,达到降氟效果仍有很大潜力,而石灰土环境在高添加铁铝盐基离子水平下继续添加FeCl3·6H2O或AlCl3·6H2O降低土壤中水溶性氟的作用较弱.从土壤pH看,黄壤水溶性氟受试验因子影响复杂,土壤pH低水溶性氟不一定低,pH在4～6时,氟元素的形态及有效性尤其复杂,而石灰土中水溶性氟基本随pH降低而降低.     

大气降尘中水溶性有机物组成与含量的研究

本文为了研究各个地区大气降尘中水溶性有机物的组成与含量,从离地表２０ 米处的电网绝缘子表面采集九个大气降尘样品,对其水溶性部分用有机溶剂进行有机物的分离萃取,求出有机物的含量,采用ＸＲＰＤ 进行物相鉴定,确定有机物的组成可分为有机酸、有机酸钾盐、有机碱·盐酸盐加合物,尿素与尿素·硝酸盐加合物等四类,并对其影响ＣａＳＯ４·２Ｈ２Ｏ 的溶解度进行一系列实验,结果表明这四类有机物对ＣａＳＯ４·２Ｈ２Ｏ 溶解度的提高均有显著影响,可提高４０ ％ － ６０ ％ ,与实际降尘样品中其溶解度平均提高５０ ％ 左右相一致。由于大气降尘中普遍存在来自土壤与燃煤飞灰所排放的ＣａＳＯ４·２Ｈ２Ｏ,研究有机物的组成与含量,这对了解局部地区环境酸化（ 湿沉降） 有其重要性。     

大气污染对悬铃木叶绿素及抗氧化酶系的影响

大气污染会影响悬铃木叶片内叶绿素含量以及活性氧清除系统,致使植物体内叶绿素含量降低,抗氧化酶系统活性上升,并使植物体内丙二醛积累增加。交通污染对植物的影响程度与工业污染相当,应引起重视。绿化可减少空气污染,提高环境质量。     

ABA对米槠和格氏栲种子发育的影响

采用酶联免疫分析法（ＥＬＩＳＡ） 提取和测定米槠和格氏栲发育过程中果实内ＡＢＡ含量,并用不同浓度ＡＢＡ喂养,测定果实不同发育期对外源ＡＢＡ的敏感性．用放射性同位素法测定ＡＢＡ对贮藏蛋白质的积累作用,结果表明：在米槠和格氏栲种子发育过程中内源ＡＢＡ 含量逐渐上升,两者均在１０ 月５ 日达到峰值,米槠为１６４８ ｎｇｇ,格氏栲为１ ４６８ ｎｇｇ,随后ＡＢＡ含量均逐渐下降．果实成熟采收时,ｃ（ＡＢＡ） 仅为高峰时的１９．随着果实的发育对外加ＡＢＡ的敏感性逐渐变小,ｃ（ＡＢＡ）＝１０－４ ｍｏｌＬ－１ 可以完全抑制１０ 月２５ 日（ 米槠） 和１０ 月１５ 日（ 格氏栲） 前种子发芽,但对完全成熟的种子ｃ（ＡＢＡ）＝１０－２ ｍｏｌＬ－１ 亦不能抑制发芽．ＡＢＡ 对成熟前期胚的贮藏蛋白质合成无影响,但能促进成熟中后期胚的贮藏蛋白质的积累作用,ＡＢＡ维持米槠和格氏栲贮藏蛋白质合成和积累作用表现在转录水平上．     

A numerical model for transient-hysteretic flow and solute transport in unsaturated porous media

A two-dimensional flow and transport model was developed for simulating transient water flow and nonreactive solute transport in heterogeneous, unsaturated porous media containing air and water. The model is composed of a unique combination of robust and accurate numerical algorithms for solving the Richards', Darcy flux, and advection-dispersion equations. The mixed form of Richards' equation is solved using a finite-element formulation and a modified Picard iteration scheme. Mass lumping is employed to improve solution convergence and stability behavior. The flow algorithm accounts for hysteresis in the pressure head-water content relationship. Darcy fluxes are approximated with a Galerkin and Petrov-Galerkin finite-element method developed for random heterogeneous porous media. The transport equation is solved using an Eulerian-Lagrangian method. A multi-step, fourth-order Runge-Kutta, reverse particle tracking technique and a quadratic-linear interpolation scheme are shown to be superior for determining the advective concentration. A Galerkin finite-element method is used for approximating the dispersive flux. The unsaturated flow and transport model was applied to a variety of rigorous problems and was found to produce accurate, mass-conserving solutions when compared to analytical solutions and published numerical results.     

二氧化硫衍生物对小鼠心、肝、肺蛋白质的氧化损伤作用

研究了二氧化硫(SO2)衍生物--亚硫酸钠和亚硫酸氢钠混合物(分子比为3:1),对小鼠心、肝、肺中蛋白质的氧化损伤作用,探讨其分子作用机制.连续5 d对动物腹腔注射SO2衍生物,每天注射剂量为0、0.025、0.100、0.400 g·kg-1.用2,4-二硝基苯肼比色法测定不同器官组织中蛋白质羰基含量.结果表明,SO2衍生物染毒剂量为0.025、0.100 和0.400 g·kg-1时,小鼠心、肝、肺蛋白质羰基含量染毒组与对照组相比均呈现不同程度的增加,不同器官羰基含量增量大小的次序为:肝＞肺＞心;其染毒剂量与心、肝、肺蛋白质羰基含量之间存在明显的剂量效应关系(p＜0.05),线性拟合确定系数分别为0.894、0.893和0.903.由此认为,SO2衍生物可引起小鼠心、肝、肺组织蛋白质的氧化损伤,以及不同组织器官的蛋白质氧化损伤程度不同.     

五氯酚对斜生栅藻的毒性效应研究

以斜生栅藻细胞的生长状况、色素(叶绿素a、叶绿素b、类胡萝卜素)及蛋白质含量的变化作为指标,研究了不同质量浓度的五氯酚(0,0.02,0.05,0.10,0.50,1.00 mg/L)对斜生栅藻(Scenedesmus obliquus)的毒性效应.24,48,72,96和120 h五氯酚对斜生栅藻的EC50分别为0.883,0.283,0.225,0.168和0.192 mg/L.斜生栅藻生长受抑制程度随五氯酚质量浓度增加而加强,当五氯酚的质量浓度超过0.50 mg/L时,斜生栅藻的生长几乎完全受到抑制.染毒96 h的斜生栅藻色素(叶绿素a、叶绿素b、类胡萝卜素)含量以及蛋白质含量随着五氯酚质量浓度的增加呈下降趋势,色素比例失调,色素对五氯酚的敏感程度为:类胡萝卜素＞叶绿素a＞叶绿素b;可溶性蛋白质含量与色素含量的减少呈明显线性相关(r=0.793,n=6).      

赤泥对电解锰渣中可溶性锰离子固化效果研究

为了探讨赤泥固化电解锰渣中可溶性锰离子的固化效果和可行性,本文采用X射线衍射(XRD)、电子扫描显微镜(SEM)和X射线荧光光谱(XRF)等分析手段,对比评估了新鲜赤泥、陈旧赤泥(堆放1年以上)、生石灰以及陈旧赤泥复合生石灰等固化剂在不同添加剂量下对电解锰渣中可溶性锰离子的固化效果,并初步阐释了赤泥固化电解锰渣中可溶性...     

Phylogenetic Comparative Methods Strengthen Evidence for Reduced Genetic Diversity among Endangered Tetrapods

Abstract: The fitness of species with little genetic diversity is expected to be affected by inbreeding and an inability to respond to environmental change. Conservation theory suggests that endangered species will generally demonstrate lower genetic diversity than taxa that are not threatened. This hypothesis has been challenged because the time frame of anthropogenic extinction may be too fast to expect genetic factors to significantly contribute. I conducted a meta‐analysis to examine how genetic diversity in 894 tetrapods correlates with extinction threat level. Because species are not evolutionarily independent, I used a phylogenetic regression framework to address this issue. Mean genetic diversity of tetrapods, as assessed by protein heterozygosity, was 29.7–31.5% lower on average in threatened species than in their nonthreatened relatives, a highly significant reduction. Within amphibians as diversity decreased extinction risk increased in phylogenetic models, but not in nonphylogenetic regressions. The effects of threatened status on diversity also remained significant after accounting for body size in mammals. These results support the hypothesis that genetic effects on population fitness are important in the extinction process.