title: Evaluation of trace metals bioavailability in Japanese river waters using DGT and a chemical equilibrium model.
abstract: To develop efficient and effective methods of assessing and managing the risk posed by metals to aquatic life, it is important to determine the effects of water chemistry on the bioavailability of metals in surface water. In this study, we employed the diffusive gradients in thin-films (DGT) to determine the bioavailability of metals (Ni, Cu, Zn, and Pb) in Japanese water systems. The DGT results were compared with a chemical equilibrium model (WHAM 7.0) calculation to examine its robustness and utility to predict dynamic metal speciation. The DGT measurements showed that biologically available fractions of metals in the rivers impacted by mine drainage and metal industries were relatively high compared with those in urban rivers. Comparison between the DGT results and the model calculation indicated good agreement for Zn. The model calculation concentrations for Ni and Cu were higher than the DGT concentrations at most sites. As for Pb, the model calculation depended on whether the precipitated iron(III) hydroxide or precipitated aluminum(III) hydroxide was assumed to have an active surface. Our results suggest that the use of WHAM 7.0 combined with the DGT method can predict bioavailable concentrations of most metals (except for Pb) with reasonable accuracy.
authors.affiliation: Graduate School of Environment and Information Sciences, Yokohama National University, 79-7 Tokiwadai, Hodogaya-ku, Yokohama, Kanagawa 240-8501, Japan. han-shuping-cw@ynu.ac.jp
authors.forename: Shuping
authors.initials: S
authors.lastname: Han
authors.forename: Wataru
authors.initials: W
authors.lastname: Naito
authors.forename: Yoshimichi
authors.initials: Y
authors.lastname: Hanai
authors.forename: Shigeki
authors.initials: S
authors.lastname: Masunaga
mesh_terms: D000536:Aluminum Hydroxide / Q000737:chemistry; D001682:Biological Availability; D004784:Environmental Monitoring / Q000379:methods*; D005290:Ferric Compounds / Q000737:chemistry; D005618:Fresh Water / Q000032:analysis / Q000737:chemistry; D007854:Lead / Q000032:analysis / Q000493:pharmacokinetics; D008670:Metals / Q000032:analysis* / Q000493:pharmacokinetics*; D008962:Models, Theoretical; D045483:Rivers / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000493:pharmacokinetics
chemical_list: D005290:Ferric Compounds; D008670:Metals; D014874:Water Pollutants, Chemical; D007854:Lead; C021024:ferric hydroxide; D000536:Aluminum Hydroxide
keywords: Bioavailability; Chemical equilibrium model; DGT; Japan; River waters; Trace metals