Radioactivity levels of recent sediments in the Butrint Lagoon and the adjacent coast of Albania

Sediment samples have been collected in the Butrint area, located in the south-west Albania to determine the radioactivity levels of 40K, 137Cs, 212Bi, 212Pb, 214Bi, 214Pb, 226Ra and 228Ac on the bed of the lagoon and adjacent sea, using direct counting gamma spectroscopy. The concentration of 137Cs and 40K varied from 2.8 to 37.5 Bq/kg and from 266 to 675 Bq/kg dry weight (dw), respectively (central values). The average concentrations of 238U and 232Th daughter products varied from 8 to 27 Bq/kg and from 13 to 40 Bq/kg dw, respectively. The measured 235U activity ranged from 0.7 to 2.5 Bq/kg dw. Samples of different sedimentary properties, studied for the radioactivity concentration, revealed an inversely proportional relation between grain size and a linear combination of measured specific activities of 226Ra, 232Th (228Ac, 212Bi and 212Pb), 40K and 137Cs.