Fractional Distributions of Trace Metals in Surface Water of Lake Biwa as Studied by Ultrafiltration and ICP-MS

Abstract

Abstract The distributions of 33 trace metals in the total dissolved fraction (TDF), small molecular weight fraction (SMWF; <10000 Da), and large molecular weight fraction (LMWF; >10000 Da) of surface water from two sampling stations (No. 1 and No. 2) in Lake Biwa (Japan) were investigated. In the experiment, the concentrations of trace metals in TDF and SMWF were determined by inductively coupled plasma mass spectrometry (ICP-MS) using a laboratory-made chelating resin-packed minicolumn for the preconcentration of trace metals. The concentrations of trace metals in LMWF were calculated by subtracting those in SMWF from those in TDF. The comparison between the distributions of trace metals in each fraction collected from the sampling stations No. 1 and No. 2 was made, and the enrichment factors of trace metals in LMWF were estimated. As a result, it was found that soluble biogenic large molecule–metal complexes and hydrogenic particulates were predominantly distributed in LMWF of surface water from Lake Biwa. Furthermore, positive anomalies of Ce and Gd were observed in the shale-normalized rare earth element (REE) distribution patterns.