Radiotoxic metals concentration measurement in sediments due to gold mining activities, Chalkidiki.

Abstract

The mining operation and tailing deposits in Stratoni region, Northern part of Greece, make monitoring activities necessary both in the terrestrial and coastal areas. As a part of a preliminary monitoring action, in summer of 2012, surface sediment samples in the coastal area of Stratoni (in Ierissos Gulf) were collected and measured aiming a) to obtain concentration levels of (Natural Occurring Radioactive Materials) NORM and heavy metals (e.g. As, Zn, Cu, Pb and Mn,), b) to identify minerals composition and c) to determine the distribution of the grain size. The activity concentrations of 238U, 232Th daughters and 40K were found between (20-100) Bq/kg, (20-35) Bq/kg and (420-700) Bq/kg, respectively. The concentrations of the most toxic heavy metals were found, (8-4100) ppm for As, (30-4000) ppm for Zn, (7-200) ppm for Cu, (40-1700) ppm for Pb and (400-26000) ppm for Mn. In addition, granulometric analysis reveals mostly sandy and sandy-mud sediments (97 – 53% content of sand). In general, enhanced levels of heavy metals and radionuclides were located near the load-out pier area of the coastal region. So, the input mechanisms of them (via local streams, rainfall, floods or others) into the sea and their levels has to be periodically investigated through more concerted monitoring actions.