137Cs, 40K and 210Po in abiotic components of aquatic ecosystems two rivers in the Can Gio biosphere reserve, Vietnam

Abstract

Determination of 137Cs, 40K and 210Po in water, bottom sediments and suspended matter of river systems of the Can Gio Biosphere Reserve, Vietnam was carried out. The average activity concentration of 137Cs in waters of Ca Gau and Long Tau was 0.89 ± 0.14 and 1.08 ± 0.15 Bq m−3 and was comparable to the levels of this radioisotope in waters of the East Sea. The activity concentration of 137Cs in bottom sediments was 2.23 ± 0.81 and 3.63 ± 1.24 Bq kg−1. The activity concentration of 137Cs in water and bottom sediments could be characterized as low. So, the water areas of the Ca Gau and Long Tau rivers could be attributed to areas with insignificant pollution by technogenic radionuclides. The 210Ро activity concentration in bottom sediments of the Ca Gau and Long Tau rivers ranged from 9.2 ± 1.2 to 25.5 ± 2.1 Bq kg−1, which is typical for river bottom sediments. Such values indicate the absence of anthropogenic enhancement of the entry of this radionuclide into the Can Gio river systems. The 40K activity concentration varied within 467 ± 42–651 ± 39 Bq kg−1 and represented typical values of potassium content in the bottom sediments of coastal water bodies, subject to a significant influence of the lithogenic component of suspended matter.