Geochemistry and water dynamics: II. Trace metals and Pb–Sr isotopes as tracers of water movements and erosion processes

A dynamic scheme for water movements over a flood in a small watershed was proposed in a previous paper [Ben Othman, D., Luck, J.M., Tournoud, M.G., 1997. Geochemistry and water dynamics: application to short-time scale flood phenomena in a small Mediterranean catchment: I. Alkalis, alkali-earths and Sr isotopes. Chem. Geol. [140] 9–28] based on major, alkali–alkali earth trace elements and Sr isotopes. In the present paper, metal contents and Pb isotope data are reported for the same samples, and compared to natural and anthropogenic local sources analysed for this purpose. Water treatment plants have stable but show relatively large variations, presumably related to yet unidentified (industrial?) Pb sources. Some Cu–Zn-rich chemicals used extensively on vineyards have unradiogenic around 17.7. Local rains sampled over two years show roughly similar low values. Pb from rocks is variable and more radiogenic ( ≈18.8–22.8). Except for the first hours, trace element concentrations in the dissolved load are similar to or slightly higher than those observed over the year, and similar to other moderately anthropogenic areas [Shiller, A.M., Boyle, E.A., 1987. Variability of dissolved trace metals in the Mississippi river. Geochim. Cosmochim. Acta [51] 3273–3277] for [Pb] (0.05–0.45 nM), [Zn] (10–75 nM) and [Cd] (0.03–0.18 nM). Dissolved [U] and [Co] show simple variations correlated to carbonate, related to local natural sources. Most trace elements in the particulate load are strongly correlated. Lead isotopes in the dissolved and particulate loads show ranges over the flood, again similar to those observed over the year ( ≈17.9–18.3), implying the same sources. The very good alignments observed in and vs. diagrams, especially for the particulate, are interpreted as mixing phenomena. Generally Pb isotopic signature of the dissolved load is less radiogenic than the particulate, indicating differences in sources or proportions and absence of isotopic equilibration with respect to the time of transfer. Pb isotopes shift regularly with time away from the road runoff endmember towards more radiogenic values. The strong negative correlation between Pb isotopes in the particulate load and Sr isotopes in the dissolved load, observed for the first time in a small watershed, probably reflects the local coupling between mechanical and chemical erosion, respectively.     

沙地麻黄育苗试验研究

文章阐述了麻黄（ＥｐｈｅｄｒａｓｉｎｉｃａＳｔａｐｆ）的生物学特性、引种繁殖技术及育苗效果,认为覆膜育苗在生产上有较高的推广价值,可以很好地开发麻黄的药用资源。     

不同方法制备的海星皂甙细胞毒性评价

考察超临界CO2萃取、乙醇萃取两种方法制备的南海产多棘海星皂甙的溶血过程,采用分光光度法测定溶血指数,结合红细胞形态血观察,评价其细胞毒性。结果显示,两种方法制备的海星皂甙都具有明显溶血作用,超临界CO2萃取、溶剂萃取的海星皂甙溶血指数分别为19231,12821,超临界CO2萃取的海星皂甙保持了更强的细胞毒性,这为海星皂甙制备工艺的选择,探索其物质基础提供了参考依据。     

有毒铜绿微囊藻对鱼和溞的毒性

用有毒铜绿微囊藻细胞及其从毒细胞中提取的毒素喂养和腹腔注射鱼类,结果表明:(1)微囊藻毒素MCYST-LR对所有实验过的鱼有毒害作用(LD₅₀为110-500μg/kg).注射毒素24h后,鱼肝电镜超微结构观察均表现出肝损伤.(2)在受控条件下,当用有毒铜绿微囊藻作为食物喂养日鲢和罗非鱼时,鱼类能在以毒藻为唯一食物的环境中生活20d以上.白鲢和罗非鱼粪便的毒性比喂食藻类的毒性分别降低约2-4.5倍,其肝的超微结构现察仍有轻度损伤.(3)在培养液中加入15μg/mLMCYST-LR和用实验室纯培养的铜绿微囊藻作为食物培养枝角类时,均可使它们在48h死亡.以无毒微囊藻培养时则生长不良亦不怀卵,表明它不是枝角类合适的食物.     

甲醛溶液对发头裸腹溞及其体表聚缩虫影响的试验

不同浓度的甲醛溶液对枝角类发头裸腹溲Ｍｏｄｉｎａｉｒｒａｓａ的致毒效应以及对其体表附着的聚缩虫Ｚｏｏｔｈａｍｉｕｍｓｐ．的杀灭效果的试验结果表明,１２ｈ、２４ｈ两俱和用时段中,甲醛浓度与发头裸腹溲相对存活率之间以及甲醛浓度与发头裸腹溲体表聚缩虫营养体脱落率之间存在一定的函数关系。     

MCTSI联合D-D评估急性胰腺炎患者临床预后的可行性分析

目的:评估MCTSI评分联合D-二聚体检测值与急性胰腺炎患者临床预后的相关性。方法:收集我院2016年8月至2018年1月间收治并确诊的急性胰腺炎患者150例,记录入院后首日血浆D-二聚体检测值,并于第5～7日行CT增强扫描检查,根据MCTSI标准进行评分,将MCTSI评分和血浆D-二聚体检测值经过Logistic回归方程得出联合检测值,并将MCTSI评分、D-二聚体检测值、联合检测值进行ROC曲线分析。结果:轻、中、重度急性胰腺炎患者血浆D-二聚体检测值及预后存在有明显差异(P <0.001),重度患者D-二聚体检测值显著高于轻、中度患者(P <0.001)。MCTSI评分和血浆D-二聚体检测值经过Logistic回归方程得出联合检测值对于患者器官功能衰竭预测的效能优于单独使用MCTSI评分及血浆D-二聚体检测值预测的效能,且其与住院天数的相关系数也最高。结论:针对急性胰腺炎患者,参照MCTSI以及D-二聚体检测值进行联合评估,可了解患者预后情况,具备较高的临床参考价值。     

菲、芘、苯并(a)芘单一暴露及分别与α-萘黄酮(ANF)联合暴露对海水青鳉(Oryzias melastigma)胚胎发育毒性效应的比较研究

为了解和探讨3~5环PAHs对海水鱼类胚胎发育的毒性及作用方式,比较研究了菲(phenanthrene,Phe)、芘(pyrene,Py)、苯并(a)芘(benzo(a)pyrene,BaP)单一暴露和三者各自与α-萘黄酮(α-naphthoflavone,ANF)联合暴露对海水青鳉(marine medaka, Oryzias melastigma)胚胎发育的毒性效应。胚胎体内EROD活性、发育畸形、孵化率和心律等毒性指标被测定,结果显示:Phe,Py和BaP对海水青鳉胚胎体内EROD活性的诱导能力大小为BaP>Py>Phe,各化合物对EROD诱导与发育畸形之间的关系较为复杂,除Phe所引起的EROD诱导与畸形指数之间呈显著相关(r=0.95,p=0.015)外,Py和BaP均无相关性;在100 μg/dm3 ANF影响下,CYP1A活性诱导被抑制,但胚胎发育的畸形指数被显著提高,ANF分别与Phe,Py和BaP的联合暴露对胚胎发育呈潜在的协同作用。本文研究初步表明,3~5环PAHs化合物对海水青鳉胚胎发育的毒性作用方式可能不同;CYP1A活性抑制在PAHs混合物对海水青鳉胚胎发育的毒性作用过程中未起到缓解毒性的作用,CYP1A抑制剂与PAH型CYP1A诱导剂的混合物对鱼类胚胎发育具有潜在的协同毒性作用,现有的PAHs混合物毒性风险评价方法可能低估了实际环境中PAHs的风险;海水青鳉早期生活阶段的心脏发育对PAHs混合物暴露较为敏感,可推荐其作为生物标志物指示PAHs或溢油污染。