Preliminary Investigation concerning Metals Bioavailability in Waters of Aries River Catchment by Using the Diffusive Gradients in Thin Films Technique

Marin Senila,Marius Roman,Lacrimioara Ramona Senila,Erika Andrea Levei

doi:10.1155/2015/762121

Marin Senila, Marius Roman + Show 2 more

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https://doi.org/10.1155/2015/762121

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Abstract

The paper presents the metals content and bioavailability in waters of Aries River catchment, Romania. Concentration of labile dissolved metal species measured by diffusive gradients in thin films technique (DGT), metals in colloidal and in particulate phases, and also general physical-chemical indicators of water were determined. Very high total metal concentrations were found in the tributaries that drain the mining areas. However, the influence of the polluted tributaries on the Aries River water quality was moderate, as a consequence of the tributaries low flow rate compared with that of the Aries River. Using the DGT technique the bioavailable metals fractions expressed as % of total dissolved metals concentrations were found to be 28–88% for Cu, 43–72% for Zn, 73–85% for Fe, and 33–70% for Mn. Depending on the used method for dissolved metals determination the classification of waters according to quality classes may differ. Excluding the colloidal metal fractions, DGT measures only truly dissolved metal concentrations. In cases with very high metal contamination the differences between total dissolved and DGT-labile concentrations are unimportant for waters classification. However, where the metals concentration is near the thresholds values the determination method is very important.

Highlights

Metals can enter in the aquatic environment via natural pathways, but the anthropogenic inputs can increase total metal concentrations above the values that may pose risks for biota [1, 2]
The accurate measurement of bioavailable metals concentration is often a difficult task considering that colloids containing metals can pass through 0.10–0.45 μm filters, introducing positive errors in the determination of truly dissolved metal concentrations
A relatively simple, but very efficient, measuring tool for the determination of truly dissolved metals in water is the diffusive gradients in thin films (DGT) technique that is based on the diffusion of labile metal species through a diffusive gel, according to their diffusion coefficients, followed by trapping in a resin gel that accumulates metals

Summary

Introduction

Metals can enter in the aquatic environment via natural pathways, but the anthropogenic inputs can increase total metal concentrations above the values that may pose risks for biota [1, 2]. Metals toxicity is influenced by their total concentration, and by their bioavailability. The metals with the highest bioavailability are those found in labile or dissolved forms [3]. The accurate measurement of bioavailable metals concentration is often a difficult task considering that colloids containing metals can pass through 0.10–0.45 μm filters (typically used for water samples filtration prior to the measurement of dissolved metal species), introducing positive errors in the determination of truly dissolved metal concentrations. A relatively simple, but very efficient, measuring tool for the determination of truly dissolved metals in water is the diffusive gradients in thin films (DGT) technique that is based on the diffusion of labile metal species through a diffusive gel, according to their diffusion coefficients, followed by trapping in a resin gel that accumulates metals

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