[A-HW28] Hydrology and Water Environment

[AHW28-P21] Measurement for Dissolved Metal Ions in River Water by ICP-MS Combined with Solid Phase Extraction

*Takuma Kitajima¹, Nobutoshi Ohtsuka^1,2, Shusuke Takemine¹ (1.Center for Environmental Science in Saitama, 2.Saitama University, Graduate School of Science and Engineering)

Keywords:Trace Metals, Chemical Equilibrium Calculations, Urban Rivers, Speciation

Dissolved metals in rivers are present in a variety of species, and the effect of their metals on aquatic organisms depends on the chemical species. The concentration of dissolved metals in each species is a key to critical data for ecological risk assessment. In addition, the forms of dissolved metals include ions, inorganic complexes, and organic ligand complexes, and the affect for aquatic organisms differs depending on the form. Currently used ecological impact models such as the Biotic Ligand Model and the Free Ion Activity Model suggest that dissolved metal ions and inorganic complexes have the bioavailability to affect aquatic organisms. Therefore, estimation of metal ion forms is also important for risk assessment. The aim of this study is to develop a method for estimating metal ion and inorganic complex concentrations by Inductively Coupled Plasma - Mass Spectrometry (ICP-MS). The metal ions and inorganic complexes in river water were attempted to be selectively extracted by a solid phase extraction cartridge filled with chelating resin (InertSep ME-2: GL Science). The extracted ions were eluted and determined by ICP-MS. In addition, a speciation analysis was performed for the same samples using the chemical modeling. The feasibility of the method was discussed by comparing the measured values with the model results.