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

Abstract EN

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.