Sorption Model for Dissolved Aluminium in Freshwaters     

S. Upadhyay  P. S. Liss  T. D. Jickells 《Aquatic Geochemistry》2002,8(4):255-275

A series of aluminium speciation measurements were madein the freshwaters of the Yare and Great Ouse rivers (England). Samples were analysedfor dissolved and particulate Al, suspended particulate matter (SPM), and other alliedchemical species in order to assess the role of sorption processes on the suspended phasesin controlling dissolved Al levels. Partitioning of Al occurs between solid andsolution phases with a distribution coefficient (K_d) which varies over about one anda half orders of magnitude for suspended particle concentrations of comparablemagnitude. A sorption model is proposed for dissolved Al concentrations in thesefreshwaters with most of the data fitting the model defined by a zone with K_dvalues of 0.316 × 10⁶ and 10⁷. However, a few data points lie outside thiszone, suggesting that other processes may also influence dissolved Al distributions.Nevertheless, the model may serve as a starting point for predicting concentrations ofdissolved Al in rivers where SPM levels are moderate to high (>1 mg l^-1 but< 75 mg l^-1), and indeed, this model works reasonably well for the Conway system(Wales). Further, the empirical distribution coefficient, K_d, decreases withincreasing suspended particle concentration, which may be due in part to colloidal phenomena.  相似文献   

Groundwater quality in the Niva River basin, Chittoor district, Andhra Pradesh, India   总被引：2，自引：0，他引：2  

Y. S. Rao  T. V. K. Reddy  P. T. Nayudu 《Environmental Geology》1997,32(1):56-63

 This study was made to assess the groundwater quality in relation to agricultural and domestic uses in a part of the Peninsular Archean granite and gneissic complex of India. Water samples were collected from the existing wells in the Niva River basin, Chittoor district, Andhra Pradesh, India and analysed for major ions. The analytical data, processed and interpreted acoording to the WHO standards, reveal that, in general, the groundwater is suitable for both agricultural and domestic uses, exept in a few locations. High concentration of nitrates were observed in some of the wells (both agricultural and domestic) that are affected by the impact of industrial effluents. Multiple regression analysis was performed and used as a positive predictive tool in understanding the chemistry of the groundwater. Received: 2 May 1996 / Accepted: 14 October 1996  相似文献   

渔塘坝独立硒矿床中硒赋存形式的电子探针分析研究   总被引：7，自引：1，他引：7  

姚林波  高振敏  杨竹森  龙洪波  叶先贤  王明再 《矿物学报》2001,21(1):49-52

利用电子探针手段分析了渔塘坝独立硒矿床中硒的赋存方式，发现硒的赋存形式为：①独立硒矿物：硒铜蓝、蓝硒铜矿、方硒铜矿、自然硒等；②类质同象方式：主要进入黄铁矿晶格。  相似文献   

紫阳富硒茶叶地质   总被引：2，自引：0，他引：2  

黎敦朋  邵颖 《陕西地质》2001,19(1):85-92

紫阳富硒茶产于北亚热带湿润季风气候条件，高硒异常区的汉江、任河及其主要支流沿岸中低浅山丘陵地貌区，其分布受温度影响明显，具有＜1000mm,1000-1300m两个垂直分带现象。紫阳富硒茶的产量主要与地质背景及微量元素含量相关，蒿坪－－流水店复式向斜志留系斑鸠关岩组和梅子垭岩组地层分布区是紫阳富硒茶开发的最佳地带。  相似文献   

Concentrations and transport of trace metals in the St. Lawrence River     

Bernadette Quémerais  Ken R. Lum  Claire Lemieux 《Aquatic Sciences - Research Across Boundaries》1996,58(1):52-68

Samples of raw water were collected in the St. Lawrence River during six sampling trips from August 1990 to April 1992. Water samples were analyzed for both dissolved and particulate phases for five trace metals. Partition coefficients (Kd) and metal fluxes were calculated in order to determine metal transport. A mass balance equation was used for the determination of the major metal sources to the St. Lawrence River and an estimation of metal loadings to the estuary was made. Average dissolved metal concentrations were found to be Cd 10 ng/L, Co 74 ng/L, Cu 64 ng/L, Fe 69 µg/L and Mn 700 ng/L. Particulate concentrations were (in µg/g) 1.68 for Cd, 31 for Co, 73 for Cu, 25 mg/g for Fe and 1.69 mg/g for Mn. Co, Fe and Mn were transported essentially in the particulate phase while Cd and Cu were predominantly found in the dissolved phase at 56% and 48% of the total metal concentration respectively. Log Kd values varied from 5.1 (for Cu) to 6.8 (for Mn). In the dissolved phase the major sources were found to be the Great Lakes and the Ottawa River whereas in the particulate phase Québec tributaries appear to be the most important. Industrial inputs are quite important in both the dissolved and the particulate phases for Cd, whereas other sources are very variable, especially for the dissolved phase.  相似文献   

几种海洋生物体内硒含量的测定   总被引：4，自引：1，他引：4  

毛文君  管华诗 《海洋湖沼通报》1995,(4):28-32

本文用石墨炉原子吸收光谱法直接测定几种海洋生物体内的硒含量。本方法的最低检出限为３０ｐｇ，变异系数低于５．９％，回收率９４％－９９％。测定发现；褐藻含硒量比红藻和绿藻低，紫贻贝和海湾扇贝的外套膜中硒含量远远高于肌肉组织。  相似文献   

Dissolved Organic Matter in Oceanic Waters   总被引：13，自引：0，他引：13  

Hiroshi Ogawa  Eiichiro Tanoue 《Journal of Oceanography》2003,59(2):129-147

The amount of information on oceanic dissolved organic matter (DOM) has increased dramatically in the last decade thanks to the advances in chemical characterization. This information has supported the development of some novel and important ideas for DOM dynamics in the ocean. Consequently, we have a better understanding of the importance of DOM in oceanic biogeochemical cycles. Here we review studies published mainly during 1995–2001, synthesize them and discuss unsolved problems and future challenges. The measurement, distribution and turnover of dissolved organic carbon (DOC) are presented as the bulk dynamics of the oceanic DOM. The size spectrum, elemental composition, and chemical compositions at molecular and functional group levels are described. The mechanisms proposed for the survival of biomolecules in DOM are discussed. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Limited nutritional benefit to the seagrass Halophila ovalis, in culture, following sediment organic matter enrichment     

K.L. Kilminster  D.I. Walker  P.A. Thompson  J.A. Raven 《Estuarine, Coastal and Shelf Science》2006,68(3-4):675

Essential nutrients for seagrass growth may be derived from benthic decomposition of organic matter. To test this idea, cores of Halophila ovalis (seagrass-vegetated) and unvegetated sediment (control) were amended with either particulate organic matter (POM) or dissolved organic matter (DOM) to test whether a positive feed-back loop exists, where increased organic matter results in increased seagrass nutrients. POM was added in the form of seagrass wrack (0, 1, 5, 12 g core⁻¹) and DOM was added with sucrose diffusion tubes at the root zone (0, 0.8, 2.4, 5.2 g core⁻¹). Cores were incubated under saturating light conditions (12 h light/12 h dark) at 18 °C, for 4 weeks. Results suggest a complex balance between positive and negative effects of organic matter enrichment. Whilst leaf molar concentrations of N and P of H. ovalis increased (by 15 and 30% respectively), plant growth declined (up to 50% relative to control) for both DOM and POM enrichments. Phosphate was removed from sediment porewater following POM addition and most likely translocated to the leaves. Stressors other than nutrient limitation (e.g. biogeochemical constraints) reduce growth and affect the nutrient dynamics of the seagrass and should be the focus of future work.  相似文献   

贻贝外套膜富硒液的研究     

毛文君  管华诗  李八方 《中国海洋大学学报(自然科学版)》1995,(Z1)

提出以贻贝的外套膜为主要原料，通过多种酶水解及其它工艺处理，研制出贻贝外套膜富硒液。分析表明，提取液富含天然有机硒、锌、铁、铜、锰微量元素及丰富的维吐素Ａ、维生素Ｅ、必需氨基酸等多种天然营养物质。  相似文献   

柘林湾水体溶解氧的分布特征及其与营养盐的关系   总被引：4，自引：0，他引：4  

杜虹  黄长江  董巧香 《台湾海峡》2006,25(2):188-193

根据2001年7月～2002年7月间对柘林湾进行的溶解氧和营养盐含量的调查数据,探讨柘林湾海域溶解氧的时空分布规律及其与营养盐之间的相关关系.结果表明柘林湾的溶解氧含量年均值为5.88mg/dm^3,呈河口、湾外高,湾内低的平面分布规律.回归分析表明,柘林湾溶解氧含量与NO3-N含量呈显著的正相关关系,与PO4-P、NH3-N含量呈显著的负相关关系.大规模的养殖生产是影响柘林湾水体DO含量的一个重要因素.  相似文献