Ultra-trace (< 1 ng g⁻¹) rare earth elements and yttrium (REE + Y) and high field strength element (HFSE) geochemistry of freshwater can constrain element sources, aqueous processes in hydrologic catchments, and the signature of dissolved terrestrial fluxes to the oceans. This study details an adapted method capable of quantifying ≥ 38 elements (including all REE + Y, Nb, Ta, Zr, Hf, Mo, W, Th, U) with minimal sample preparation in natural water aliquots as low as ≤ 2 mL. The method precision and accuracy are demonstrated using measurement of the National Research Council – Conseil national de recherches Canada (NRC-CNRC) river water certified reference material (CRM) SLRS-6 sampled from the Ottawa River (OR). Data from SLRS CRM are compared to those of new, filtered (< 0.45 µm) stream water samples from the central Ottawa River basin (ORB), and discussed in terms of processes and geochemical signatures inherited from the highly evolved igneous/metamorphic Archean and Proterozoic bedrock in the catchment. The ORB waters have significantly LREE > HREE-enriched REE + Y patterns, small natural positive Y and Gd anomalies, and negative Eu and Ce anomalies. These REE + Y features are coherent downstream in the OR apart from amplification of Eu and Ce anomalies during REE removal/dilution. The OR samples capture a downstream decrease in sparingly soluble HFSE (Th, Nb, Ta, Zr, Hf), presumably related to their colloid-particulate removal from the dissolved load, accompanied by crustal Zr/Hf (32.5 ± 5.1) and supercrustal Nb/Ta (25.1 ± 7.7) ratios. Subcrustal Th/U (0.17–0.96) and supercrustal Mo/W (12.0–74.5) ratios in all ORB waters indicate preferential release and aqueous solubility of U > Th and Mo > W, with the latter attributed primarily to preferential W adsorption on soil or upstream aquatic (oxy)(hydr)oxide surfaces.

超痕量（<1 ng g ^-1）稀土元素和淡水的钇（REE + Y）和高场强元素（HFSE）地球化学可以限制元素来源，水文集水区的水过程以及溶解的海洋通量到海洋的签名。这项研究详细介绍了一种适用的方法，该方法能够以最少的样品制备量（最低等分于≤2 mL），以最少的样品定量方法量化38种以上元素（包括所有REE + Y，Nb，Ta，Zr，Hf，Mo，W，Th，U）。该方法的准确性和准确性通过使用加拿大国家研究委员会（Conseil National de rechesches Canada）（NRC-CNRC）取自渥太华河（OR）的河水认证参考物质（CRM）SLRS-6的测量方法进行了证明。将来自SLRS CRM的数据与来自渥太华河流域中部（ORB）的经过过滤（<0.45 µm）的新流水样品的数据进行比较，从集水区高度演化的火成/变质太古代和元古代基岩继承的过程和地球化学特征进行了讨论。ORB水域具有明显的LREE> HREE富集的REE + Y模式，小的自然正Y和Gd异常，以及负Eu和Ce异常。这些REE + Y特征在REE去除/稀释过程中除了Eu和Ce异常放大之外，在OR下游是一致的。OR样品捕获了少量难溶的HFSE（Th，Nb，Ta，Zr，Hf）的下游下降，大概与从溶解负荷中除去胶体微粒有关，伴有地壳Zr / Hf（32.5±5.1）和超硬壳Nb / Ta（25.1±7.7）比。次结壳Th / U（0.17–0.96）和超结壳Mo / W（12.0–74）。