X射线荧光光谱分析中熔融制样法的改进与应用

对于高硅、高铝、高铁等类的酸性样品,在熔融制样时,通过加入碱性氧化物来提高熔融体的碱性,消除酸性熔融体的不熔物,提高熔融体的流动性,使熔融体混和均匀,提高了制样的重现性,使准确度得到了提高。     

Heterotrophic potentials and trophic status of ten New Zealand lakes

A comparative study of the heterotrophic potentials of ten New Zealand lakes was carried out. Two sampling periods were chosen, one during late August and early September 1972 (late winter, minimal thermal stratification) and another during February 1973 (mid summer, strong thermal stratification in all but two lakes). A wide range of heterotrophic potentials occurred which enabled the lakes to be placed in the following basic groups according to descending trophic levels:

Group I: Rotowhero (thermal, acid lake) >Rotorua>Okaro

Group II: Rotokakahi> Tikitapu >Okareka

Group III: Rotoma = Rotoroa (S.I.) = Rotoiti (S.I.) = Okataina

Maximum values for heterotrophic potential (Vm a x ) in micrograms of glucose per litre per hour were: Maximum heterotrophic activities were found within the metalimnion, except in Lakes Tikitapu and Rotokakahi, where maximum activities occurred within the hypolimnion.     

论原始海洋水的酸碱度

通过对地球各圈层岩性、流体演化特征及类地行星岩石、大气特征的考察 ,对产生酸碱机理及生物生存繁衍进化基本条件的研究 ,认为古地球强还原性原始海水偏碱性。强还原性的古地球无Cl2 、F2 等强氧化剂物质存在 ,无由它们直接产生HCl、HF的可能 ;氮主要以N2 、NH3 形式存在 ,硫呈S2 -、S2 -2 、S0 形式存在 ,碳主要呈碳氢化合物、碳的低价氧化物、C0 等还原态存在 ,缺游离氧将它们氧化成高价而产酸。而大量基性、超基性岩浆喷溢出地表使原始海洋水呈碱性 ,由于碱金属、碱土金属及其合金氢化物与硅的氢化物一同迁移至地表 ,即使含硅很高的酸性岩其热液流体也呈碱性。     

Alkalinity buildup during silicate weathering under a snow cover

Results from the study of experimental plots at Hubbard Brook, New Hampshire for the years 1987, 1988, 1993, 1994, 1995, and 1996 show that the water draining from under a plot planted with pine trees exhibits its highest alkalinity during the year at about the time of spring snowmelt. This high alkalinity is believed to be due to buildup during the winter under a snow cover. The soil solutions are protected from acidic precipitation by the snow, and the natural process of the reaction of organic acids and carbonic acid with minerals and exchange complexes to form dissolved HCO₃ ^– (and organic anions) proceeds with an increase in alkalinity through the winter. When the snow melts the acidic meltwater mixes with, neutralizes and displaces the water previously occupying the soil interstices. This leads to a decided drop in alkalinity of the drainage water. The alkalinity buildup under the pine plot was found to be two to ten times greater than under a similar plot containing no higher plants. This strongly emphasizes the important role of plants, in their ability to produce organic acids and high levels of CO₂, in accelerating the weathering of silicate minerals.     

Recent environmental changes in a naturally acidic rocky lake in southern Finland, as reflected in its sediment geochemistry and biostratigraphy

Paleolimnological methods are combined with statistical multivariate analyses (PCA and CCA) to study the effects of local environmental disturbances and changes in loading of atmospheric origin on water acidity and the physiochemical properties of the sediment in a small, naturally acidic rocky lake in southern Finland. The pH of the lake as calculated from the diatom flora increased by 0.9 pH units as a consequence of a forest fire in the catchment area at the turn of the last century, and the changes in the diatom assemblages point to an increase in dys(eu)trophy and turbulence. In terms of element influx (in µg cm^-2 yr^-1), the effects of the fire are seen in a slight increase in the accumulation of lithophilous elements. Diatom-inferred pH values decline upwards in the sediment, but do not regain the level recorded before the fire. This is attributed to reactions between Fe³⁺ and S, which has partly accumulated from the air as SO^2-, producing internal alkalinity. Accumulation rates of many elements increase markedly after the 1960s, an effect for Al, Mg, Na, P and Zn may be connected mainly with the enhanced accumulation of dry matter, whereas the accumulation of K, Ni, Pb, Ti and V in surface sediment are obviously related to atmospheric loading. Measured accumulation rates of Cd and Cu are lower than the calculated values especially in the surface sediment, possibly because of diagenetic changes. Accumulation of Ca and Mn decreases towards the surface on account of acidification of anthropogenic origin.     

氯化钠和碱度对罗氏沼虾仔虾的毒性研究

实验研究氯化钠、碱度对罗氏沼虾仔虾的急性毒性作用。用概率单位法求出了其氯化钠2 4、4 8、72、96 h的半致死浓度分别为 8.58、 5.32、 3.4 7、 2 .19g/ L;碱度的 2 4、4 8、72、96 h半致死浓度分别为 51.0 2、 37.0 7、 2 7.19、 2 1.54mmol/ L。对氯化钠和碱度混合作用的结果进行的方差分析表明 ,氯化钠和碱度对仔虾的死亡率影响显著 ,而两者的交互作用不显著。碱度 (AL K)与罗氏沼虾仔虾氯化钠 2 4、4 8h L C50 (S)关系式分别为 S=- 0 .12 78AL K+ 9.2 346 ,S=- 0 .0 715AL K +5.530 1。     

A Revised Analytical Method for HCO3- and CO32-Determinations in Geothermal Waters: An Assessment of IAGC and IAEA Interlaboratory Comparisons

A statistical evaluation of the results of HCO₃^‐ determinations in geothermal waters during the interlaboratory comparison programmes of the International Association of Geochemistry and Cosmochemistry (IAGC) and International Atomic Energy Agency (IAEA) indicated that the analytical uncertainty increases with decreasing concentration of HCO_3‐ and was ? 25% for 50 μg ml^‐1 and ? 60% for 25 μg ml^‐1 of HCO₃^‐. The analytical method (Method 1) used by chemists and hydrologists works well for waters containing carbonic alkalinity, whereas Method 2 used by geochemists is conceptually incorrect. A stepwise comparison between the theoretical and experimental titration results for a given concentration Na₂CO₃ (0.0988 mol l^‐1) solution was performed to understand the limitations of the titration method for geothermal water analysis. Backward titration from the carbonic acid equivalence point (H₂CO₃EP) to the original pH after CO₂ removal, as had been practised earlier in the geothermal industry, in order to estimate the contribution of silicic and boric alkalinities to the total alkalinity, is incorrect because the amount of standard base (NaOH) added is equivalent to silicic and boric alkalinities plus some OH^‐ alkalinity. In a Na₂CO₃ solution, the added NaOH is equivalent to OH^‐ alkalinity only. Backward titration is only needed from the forward titration end point to the H₂CO₃EP in order to correct the total alkalinity for the excess of standard acid (HCl) added during the forward titration. In the case of a Na₂CO₃ solution, the H₂CO₃EP, after removal of CO₂ during the forward titration, is at pH = 7, not at pH = 4.5 (3.8) as has been considered in literature. Similarly, the liberation of CO₂ during titration occurs well before the point expected theoretically and it is less for shorter titration time. The revised procedure for the determination of carbonic species concentration is presented and illustrated for a water sample from Alchichica Lake, Puebla, Mexico.     

云南祥云县王家庄碱性温泉水化学特征与成因分析

位于云南省祥云县刘厂镇的王家庄温泉水样YMD10-1(王家热水井)与YMD10-2(聚龙温泉宾馆热水井)的矿化度为1.49~1.65 g/L,主要阳离子为Na^+,主要阴离子为HCO3^-,水化学类型均为HCO3-Na型。YMD10-1和YMD10-2的p H值野外测定数据分别为10.8和7,因YMD10-2暴露于空气使其pCO2较高导致其p H野外观测值偏低;实验室p H测定值分别为8和7.6,主要受到pCO2差异影响导致水中碳酸组分发生变化而改变了其p H值。水样的δ^2H-δ^18O数据显示温泉的补给来源为大气降水。利用Si O2温标估算了温泉的地下热储温度为89~92℃。利用226Ra-222Rn法估算出YMD10-1的热水年龄为446.84 a,YMD10-2的热水年龄为319.56 a。估算的地下热水的循环深度为3 808~3 898 m,利用δ^2H和δ^18O估算热水补给高程为2 845~2 865 m,补给区为周边的山区。地下水获得大气降水入渗补给后,经历深循环并获得深部热流加热,沿断裂带上升穿透浅部第四系出露地表。温泉显示碱性是由于长石与水和CO2发生反应,产生大量的HCO3^-,HCO3^-在溶液中有可能水解消耗H^+产生OH^-。王家庄温泉被当地人们用来晒制土碱,与热水Na^+和碳酸的含量高有关。     

近平衡状态海水中方解石和文石沉淀速率及动力学研究

利用"freedrift"开放反应系统,研究人工海水中近沉淀平衡状态时二氧化碳分压(p(CO2))的变化对方解石、文石沉淀速率及其动力学方程的影响.反应在恒定的温度(25.0℃±0.2℃)、p(CO2)环境下进行,通过实验得到了不同p(CO2)环境下,方解石和丈石的沉淀速率及动力学方程.研究发现:(1)晶体类型和碳酸盐...