| Popis: |
Radiological risks associated with 40K, 226Ra and 232Th massic activities in limestones, marls, stream sediments, and soils of the Kaštela Bay (Croatia) coastal area were assessed by calculating outdoor absorbed dose rates in air (D), annual outdoor effective dose rates (Def), radium equivalent activities (Raeq), and external hazard indices (Hex). Radionuclides relative contributions to D and Hex were determined for all four types of samples as well as their total contribution to Hex in all samples. D, Def, Raeq, and Hex were the lowest in limestones and the highest in soils. Maximum Raeq and Hex in soil were below the recommended values of 370 Bq/kg and 1.0. No adverse radiological effects were determined in the researched area. The most important contribution to D and Hex in limestones was almost exclusively from 226Ra, in marls from 40K, in stream sediments from 226Ra and in soils from 232Th. The most significant total contribution to Hex in all samples came from 226Ra and 232Th, and the lowest came from 40K. 226Ra showed the largest variability of its total contribution to Hex, with tendency to higher values. Special attention should be given to 226Ra when studying radiological risks in typical karstic areas, irrespectively of other possible influences of geological background. |
