Atmospheric depositional fluxes of 210Pb in bulk precipitation at the Adriatic coast, Croatia

Abstract

The atmospheric bulk depositional fluxes of ²¹⁰Pb were measured at a station on the Adriatic coast, Croatia over 4 years period from March 2017 to December 2020. The monthly depositional fluxes followed oceanic deposition patterns with a lower flux between 0.0735 and 16.9 Bq m^-2 month^-1. The volume-weighted activities were 0.000514 and 1.35 Bq L^-1 and decreased with increasing precipitation. A clear seasonal trend was observed with higher depositional flux in autumn and minimum value in the winter season. The average annual bulk depositional flux and volume-weighted activities of ²¹⁰Pb were 73.8 Bq m^-2 y^-1 and 0.119 Bq L^-1 respectively. The precipitation normalized enrichment factor (α) indicates higher depositional fluxes of ²¹⁰Pb during summer and spring than desired value according to the amount of precipitation. We found that the ²¹⁰Pb depositional fluxes in the coastal stations are lower due to ²¹⁰Pb-depleted oceanic air masses and increase with the amount of precipitation.

Keywords: Adriatic coast; Correlation; Depositional flux; Oceanic pattern; Precipitation.