Analyse og vurdering av ulike tilstandsformer til tungmetaller i avrenningsbekker fra skytebaner

Abstract

The aim of this work was to study the speciation of lead (Pb), copper (Cu), zink (Zn) and antimony (Sb) in selected shooting ranges, and how the speciation of these elements varied under different conditions /episodic events (i.e water discharge, pH). Three shooting ranges were selected; Steinsjøen, Avgrunnsdalen and Hengsvann. Water samples were collected during winter/spring 2003. Samples were both in situ size- and charge fractionated, using filtration, ultrafiltration and ion exchange. In Steinsjøen an automatic water sampler was used in addition to collect samples every 12hr during june 3-20. Samples from the automatic sampler was collected 2-3 times a week and fractionated in the lab as soon as possible. The speciation study indicated that in the investigated shooting ranges lead was mainly associated to particles and colloids. Copper was mainly found in the colloid fraction (on average 60 %) and in the <10 kDa fraction (35 %). Zink and antimony was mainly found as low molecular species, on average 60 % and 84 % respectively. A large fraction of Zn was as labile ions, while Sb was mainly present as a negative specie. When the water discharge increased an increased concentration of all elements was observed.