Using Sediment Budgets to Investigate the Pathogen Flux Through Catchments

We demonstrate a materials budget approach to identify the main source areas and fluxes of pathogens through a landscape by using the flux of fine sediments as a proxy for pathogens. Sediment budgets were created for three subcatchment tributaries of the Googong Reservoir in southeastern New South Wales, Australia. Major inputs, sources, stores, and transport zones were estimated using sediment sampling, dam trap efficiency measures, and radionuclide tracing. Particle size analyses were used to quantify the fine-sediment component of the total sediment flux, from which the pathogen flux was inferred by considering the differences between the mobility and transportation of fine sediments and pathogens. Gullies were identified as important sources of fine sediment, and therefore of pathogens, with the pathogen risk compounded when cattle shelter in them during wet periods. The results also indicate that the degree of landscape modification influences both sediment and pathogen mobilization. Farm dams, swampy meadows and glades along drainage paths lower the flux of fine sediment, and therefore pathogens, in this landscape during low-flow periods. However, high-rainfall and high-flow events are likely to transport most of the fine sediment, and therefore pathogen, flux from the Googong landscape to the reservoir. Materials budgets are a repeatable and comparatively low-cost method for investigating the pathogen flux through a landscape.     

年轻地下水定年研究综述

将环境示踪技术用于地下水定年以确定地下水的相关时间尺度问题在过去几十年中得到了长足发展,尤其是在年轻地下水定年方面。目前国内外用到的年轻地下水环境示踪剂有多种,这些示踪剂在地下水定年方面各有利弊。本文的目的是对国内外现有的9种年轻地下水示踪剂(3 H、3 H/3 He、4 He、35S、36 Cl/Cl、85 Kr、222 Rn、CFCs和SF6)的来源、示踪原理、误差来源、优缺点、适用性和应用现状等进行归纳和总结,为研究者、管理者和决策者在应用时提供参考。     

贵阳市土壤地球化学背景与生态环境分析

通过1∶250 000多目标区域地球化学调查,获得了贵阳市及邻区表、深层土壤中54项化学指标的地球化学背景值、基准值等参数。研究区总体土壤环境呈中偏酸性,对生态环境影响较大。土壤化学物质组成丰富,地球化学背景分布不均匀。除活动性强的化学组分对成土母质有分异外,多数化学组分对成土母质继承性显著。表层土壤有机碳、全碳、硫、氮、硒、氟和汞、镉、砷等的地球化学背景值显著高于深层土壤和我国其它城市地球化学基准值。前者适宜发展生态富硒特色农业,后者表明土壤环境安全形势严峻。土壤地球化学背景为生态环境评价和其它相关学科研究提供了科学基础,由此提出生态环境保护和利用建议。     

陕西绥德地区黄土-古土壤序列地球化学特征及其环境指示意义

黄土高原北部的绥德地区处于干旱-半干旱地区,对环境变化的响应十分敏感,通过对黄土-古土壤的研究对比可以探索该区的古环境气候特征、环境变化信息等相关问题.本文对绥德黄土-古土壤进行常量、微量、稀土元素测试分析,并与其他地区黄土的地球化学特征进行了对比.结果 表明:绥德地区黄土-古土壤的主要化学成分以SiO2、Al2O3、...     

湘西北黑色泥灰岩风化剖面重金属富集的地球化学机制

通过对湘西北地区黑色泥灰岩风化剖面（DM剖面）中Cr、Ni、Cu、Zn、Cd、Pb、Th、U 8种重金属元素地球化学特征的研究,并与区域上发育于黑色页岩的2条风化剖面的对比分析,初步揭示了黑色泥灰岩风化剖面中重金属富集的地球化学机制。结果表明：（1）与黑色页岩相比,黑色泥灰岩风化成土过程中重金属元素普遍呈现出低背景、高富集的地球化学特征。（2）黑色泥灰岩风化剖面的形成,是在基岩中碳酸盐快速溶蚀的基础上（基岩的酸溶相含量为78.57%）,由酸不溶相进一步演化的结果。在此过程中,对于无明显外源输入的元素Cr、Ni、Cu、Zn、Pb、Th、U,一方面,赋存在酸溶相的部分随碳酸盐的淋失而亏损甚至强烈亏损（其中Th相对惰性）;另一方面,残余在酸不溶相的部分因基岩中大量碳酸盐的淋失而显著富集,且随风化剖面的演化未显示出进一步的亏损。因此,这些元素在风化剖面中的富集是绝对（强烈）亏损和显著相对富集的综合结果。对于Cd,存在明显的外源输入,可能主要以水溶态形式带入并大量淀积在剖面下部。（3）在黑色泥灰岩风化剖面,有机质（OM）不是重金属元素的主要赋存介质,其对重金属元素地球化学行为的影响有限。（4）黑色泥灰岩发育的土壤中,Cu和Cd的平均含量分别为54.58 mg/kg和0.58 mg/kg,高于农用地土壤污染风险筛选值,特别是Cd,对土壤生态环境可能形成不利影响,应引起关注。     

浙江省中部萤石产区氟环境与地方性氟病

通过对浙江省中部萤石产区氟地球化学环境的初步研究，探讨了该区地方性氟病的成因和分布规律，指出了地方性氟病与高氟环境的关系。     

Reconnaissance soil geochemical survey of Gibraltar

The extreme density of population of Gibraltar, situated at the southern tip of Spain, exerts considerable pressure on land use and thus future planning is of utmost importance. An initial reconnaissance soil geochemical survey of Gibraltar was based on 120 surface samples (0–15 cm) taken from a wide range of exposed, either bare soil or vegetated sites, to provide the optimum geographical distribution. The total elemental concentrations of 26 elements (Li, Na, K, Be, Mg, Ca, Sr, Ba, Al, La, Ti, V, Cr, Mo, Mn, Fe, Co, Ni, Cu, Ag, Zn, Cd, Pb, P, S, As) were determined by nitric/percholric acid digestion followed by inductively coupled plasma-atomic emission spectrometry (ICP-AES) analysis. The reconnaissance data shows that the spatial distribution of various elements depended on previous and present land use. Most elements (Ca, Cr, Mg and Mn excluded) exhibited relatively high concentrations in civilian and natural soils. Trends have been established for many elements, and concentrations exceeding guideline values have been found in certain areas of Gibraltar. This reconnaissance of Gibraltar is at present being followed by a more detailed baseline geochemical survey, which will establish the extent and magnitude of the variations in major and trace elements in soils and dusts, assess the impact of industrial, commercial and urban development on the geochemical landscape and to make recommendations concerning sustainable development.     

Trace Metal Distribution and Enrichment in Benthic, Estuarine Sediments: Southport Broadwater, Australia

The distribution and enrichment of selected trace metals (Cd, Cr, Cu, Ni, Pb, Sn, Zn) in benthic sediments of the Southport Broadwater, a semi-enclosed coastal body of water adjacent to the Gold Coast city, south-eastern Queensland, Australia, was studied with the objective of assessing the extent and degree of sediment contamination. Sediment samples from the 0–10 cm and 10–20 cm depth intervals of 32 sites within the Southport Broadwater and surrounding residential canals were analysed for particle size distribution, pH, organic C and ‘near-total’ major (Al, Ca, Fe, Mn) and trace (Cd, Cr, Cu, Ni, Pb, Sn, Zn) metal contents. Sediment contamination for each trace metal was assessed by (1) comparison with Australian sediment quality guidelines, (2) calculation of the index of geoaccumulation based on regional background values, and (3) geochemical normalisation against Al (i.e. the abundance of alumino-silicate clay minerals). Based on this approach, the results indicate that submerged sediments in the study area are not presently enriched with Cd, Cr or Ni, with the spatial distribution of these metals being very well explained by the abundance of alumino-silicate clay minerals. However, several sites were strongly enriched with Cu, Pb, Sn and Zn, arising from sources related to either urban runoff or vessel maintenance activities. The study indicates that several varying approaches are needed for a satisfactory assessment of contaminant enrichment in estuarine sediments.     

初论元素富集成矿的地球化学机理—以岩浆热液矿床的形成为例

元素富集成矿的过程实质上是元素在地球不同圈层和不同相以及不同集合体之间分配的结果。元素的富集起始于地球形成的初期。对于大多数金属成矿元素 ,地壳特别是上地壳是大多数矿石和矿胎的储库 ,地壳丰度是元素富集成矿的物质基础。元素在地质体系演化共存相间的分配是元素富集成矿的关键过程。对于以侵入体为中心的热液矿床的形成 ,岩浆部分熔融、结晶分异、液态分离、挥发分分离以及气液相不混溶等过程能够导致金属元素最终达到矿石级的富集。挥发分则是元素富集成矿的重要制约因素     

贵州独山锑矿田地质地球化学特征和构造动力热液成矿

独山锑矿田位于独山箱状背斜核部近倾伏端,矿床、矿体的产出严格受断裂控制,其半坡式锑矿呈脉状产于下泥盆统、志留系碎屑岩的陡倾斜断裂中;其巴年式的锑矿呈层状产于中泥盆统碎屑岩与碳酸盐岩之间的层间滑动带中。成矿温度低,矿石组分和围岩蚀变简单,锑主要来源于下伏地层,硫主要来源于赋矿地层．成矿流体主要为大气降水,构造动力成矿作用导致锑矿床的形成,矿床类型为一典型的构过动对热液矿床。