Determination of Trace Elements in the River Aare (Switzerland) by Neutron Activation Techniques

Abstract

More than 20 trace and minor elements were determined in water samples and in the suspended load of the river Aare (Switzerland) using a simple sample preparation technique and subsequent instrumental neutron activation analysis. The water samples were irradiated without preconcentration. The interfering activity of ²⁴Na was eliminated with hydrated antimony pentoxide. The trace elements were co-precipitated as sulfides and hydroxides and were analyzed on Ge(Li)gamma-ray spectrometers. Particulate matter was filtered off in the field, irradiated and assayed by γ-ray spectroscopy. Main results: (a) the concentrations of all the elements investigated are much lower than WHO-limits for drinking water; (b) human activities are responsible for an increase of some elements along the river: (c) concentrations of dissolved trace elements are anticorrelated to the amount of water; (d) concentrations of trace elements in particulates (μg/l) are correlated to the amount of water: (e) significant correlations for elements do not exist between all four sampling stations (exception: Ca-Sr); (f) most of the elements in the suspended solids (μg/g) and in the water phase (μg/l) are not correlated.