[210]Po and [210]Pb concentration in environmental samples of the Adriatic Sea

ABSTRACT

This study reports the concentrations of important tracers of the marine environment, [210]Po and [210]Pb, in different matrices from field samples collected at Central Adriatic Sea [Italy], a non-contaminated marine ecosystem. [210]Po concentration appears to decrease with increasing distance from the coast and a significant difference in [210]Po concentrations in seawater samples at two different depths is not appreciable. [210]Po and [210]Pb present the same trend in the different periods of the year. [210]Po and [210]Pb present high concentration factors and high Kd values in particular [210]Po shows values of 2.4 10[4] in plankton, 3.2 10[5] in the particulate fraction and 1.1 10[5] in sediment; [210]Pb shows values of 1.3 10[4] in plankton, 1.8 10[4] in the particulate fraction and 4.9 10[4] in sediment. The [210]Po/[210]Pb ratio results < 1 in sea water and >1 in the particulate fraction, sediment and plankton due to a significant fractionation occurring between the two radionuclides during their removal from solution to particle and due to their different biogeochemical cycling pathways in the marine environment. The noticeable accumulation of [210]Po in the food chain is not accompanied by an identical accumulation of [210]Pb. Due to its biomagnification in the marine food chain, [210]Po provides the larges radiation dose to any marine organism under natural conditions. The data reported provide reference values for the Central Adriatic [Mediterranean Sea] coastal environment