Biogeochemistry, regional sampling

The product contains information about different elements in brookwater plants as well as pH in running water. Analytical results are presented using different analytical methods, both total and acid lactic levels have been determined. The product is the direct result of many years of geochemical mapping software. Geochemical mapping at SGU is mainly conducted for the purpose of showing the natural occurrence of major substances and trace elements in aquatic plants as well as pH in water. In regional biogeochemical mapping, brookwater plants such as various Carex species (roots), Filipendula ulmaria (roots) and Fontinalis antipyretica (whole plant) were sampled and analysed. Plants were collected from smaller streams with a sample density of 1 sample per 7 km2. The brookwater plants (roots) and moss are considered to be sample media that, without separation, absorb trace elements and therefore reflect the brookwater chemistry. Breeding aquatic plants are exposed to both natural and anthropogenic influences. Due to chemical weathering processes, metal concentrations in stream water indicate the chemical composition of surrounding bedrock and soil. The exchange of metals between water and plant roots is a slow process that does not seem to be affected by seasonal fluctuations. It can be estimated that biogeochemical samples show bioavailable metal concentrations in aquatic plants. The main and trace elements i analysed in plant samples originate from the living roots and leaf moss, as well as from minerogenic materials and iron-manganese hydroxides associated with the plant. Other geochemical sources, such as humus particles, are considered to be of minor importance. The plant samples have been analysed on 30 elements with X-ray fluorescence (XRF), where Al, As, Ba, Ca, Cl, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, P, Pb, Rb, S, Si, Sr, Ti, U, V, W, Y, Zn and Zr have given sufficient analytical quality to be used for interpretation. A subset of samples has also been analysed on Hg, Cd, Se, Au, Sb, Bi and Tl with acidification combined with atomic absorption spectrometry (AAS) and inductively coupled plasma mass spectrometry (ICP-MS). Results from fourteen elements (As, Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb, Se, U, V, W and Zn) have been regularly published on SGU in the form of reports, maps and databases. The test results show how dispersal patterns of different elements in watercourses vary within the country. Variation is due both to the natural addition of soils and bedrock and to the addition of various sources of pollution.本数据集涵盖溪生植物的各类组分信息以及溪流水体的pH值。分析结果通过多种分析方法获取，已测定各元素的总含量及酸可提取态水平。本数据集系多年地球化学填图工作的直接成果。瑞典地质调查局（SGU）开展的地球化学填图工作，主要旨在表征水生植物中主要物质与微量元素的自然赋存状态，以及水体的pH值。在区域生物地球化学填图中，研究人员对溪生植物开展了采样与分析，涵盖各类薹草属（Carex）植物（根部）、旋果蚊子草（Filipendula ulmaria，根部）以及长叶水藓（Fontinalis antipyretica，全株），采样点位均设于小型溪流中，采样密度为每7平方千米1个样品。溪生植物（根部）与苔藓被视为无需额外分离即可吸附微量元素的采样介质，其元素组成可直接反映溪流水体的化学特征。生长于溪流中的水生植物同时受到自然作用与人为活动的双重影响。由于化学风化作用，溪流水中的金属浓度可反映周边基岩与土壤的化学组成。水体与植物根系间的金属交换过程较为缓慢，似乎不受季节波动的影响。据此可推断，生物地球化学样品所表征的为水生植物体内的生物可利用态金属浓度。植物样品中分析得到的主量与微量元素，其来源包括活的根系与叶部苔藓，以及与植物伴生的成矿物质与铁锰氢氧化物。腐殖质颗粒等其他地球化学来源的贡献则被认为相对次要。研究人员采用X射线荧光光谱法（X-ray fluorescence, XRF）对植物样品中的30种元素开展了分析，其中铝（Al）、砷（As）、钡（Ba）、钙（Ca）、氯（Cl）、钴（Co）、铬（Cr）、铜（Cu）、铁（Fe）、钾（K）、镁（Mg）、锰（Mn）、钼（Mo）、钠（Na）、镍（Ni）、磷（P）、铅（Pb）、铷（Rb）、硫（S）、硅（Si）、锶（Sr）、钛（Ti）、铀（U）、钒（V）、钨（W）、钇（Y）、锌（Zn）及锆（Zr）的分析质量满足后续解释工作的要求。另有部分样品经酸化处理后，采用原子吸收光谱法（atomic absorption spectrometry, AAS）与电感耦合等离子体质谱法（inductively coupled plasma mass spectrometry, ICP-MS）分析了汞（Hg）、镉（Cd）、硒（Se）、金（Au）、锑（Sb）、铋（Bi）及铊（Tl）等元素。十四种元素（As、Cd、Co、Cr、Cu、Hg、Mo、Ni、Pb、Se、U、V、W及Zn）的分析结果已定期以报告、地图及数据库的形式在SGU发布。本次测试结果揭示了瑞典境内不同元素在水系中的分散模式差异，这种差异既源于土壤与基岩的自然输入，也与各类污染源的人为排放有关。