MERCURY IN THE IDRIJCA RIVER SEDIMENTS AS A REFLECTION OF MINING AND SMELTING ACTIVITIES OF THE IDRIJA MERCURY MINE

Stream and flood plain sediments along the valley of the Idrijca River were systematically sampled. Upstream of the mercury mining town of I drija, the Hg in stream sediment varies around 2 mg/kg. Mecury content s in the region from Idrija downstream to the town of Spodnja Idrija a re from 100 to 1,000 mg/kg. Downstream from Spodnja Idrija, sediments contain lower Hg (from 5 to 300 mg/kg). Recent overbank sediments are enriched relative to the stream sediments downstream of Idrija. River flood plain sediments that represent an accumulation of polluted sedim ents have Hg contents of 100 to 200 mg/kg.