Effects of radionuclides on the recent foraminifera from the clastic sediments of the Canakkale Strait-Turkey

Abstract

The radionuclides that cause radioactivity accumulate in the sediments as they descend to the seabed, similar to heavy metals. As radionuclides are present on the surface of the sediment or within the sediment, marine benthic foraminifera can be affected by the radioactive pollution. In this study, the habitat of benthic foraminifera was evaluated for radioactive pollution in the Canakkale Strait, which constitutes the passage of the Marmara Sea and the Aegean Sea. In 2015, seven core samples and one drilling sample were taken from the shallow marine environment, which is the habitat of benthic foraminifera, in the Canakkale Strait. Locations of the core samples were specifically selected to be pollution indicators in port areas. Gamma spectrometric analysis was used to determine the radioactivity properties of sediments. The radionuclide concentration activity values in the sediment samples obtained from the locations were Cs-137: <2-20 (Bq/kg), Th-232: 17.5 583 (Bq/kg), Ra-226: 16.9-48.6 (Bq/kg) and K-40: 443.7-725.6 (Bq/kg). These values were compared with the Turkish Atomic Energy Agency (TAEK) and the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) data and environmental analysis was carried out. The Ra-226 series, the Th-232 series and the K-40 radionuclides accumulate naturally and increase continuously due to anthropogenic pollution. Although the Ra-226 values obtained in the study areas remained within normal limits according to UNSCEAR values, the K-40 and Th-232 series values were observed to be high in almost all locations. The values of Cs-137 were found to be maximum 20 in canakkale Dere Port and they were parallel to the values in the other places. In the study, 13 genera and 20 species were identified from core and drilling samples. The number of foraminifera species and individuals obtained at locations with high pollution was very low compared to those in non-polluted zones. (C) 2017 Elsevier Ltd. All rights reserved.