Vertical distribution and inventories of 239+240Pu and mercury in Sagua la Grande estuary, Cuba

The vertical activity distribution and inventories of 239+240Pu profile and Hg were determined in Sagua la Grande estuary, Cuba. The shape of the 239+240Pu profile in the core column resembled very closely the history of atmospheric nuclear weapons' testing, and the maximum deposition in 1963 was recorded in the sediment core history. The 239+240Pu activity concentrations in the surface layer sediments varied from 0.163 to 0.611 mBq g−1. The inventory of 239+240Pu was 42 ± 5.6 Bq m−2, a value close to that expected from direct global fallout. Using the 239+240Pu as a chronomarker the mass sedimentation rate in the area for the last 60 years was calculated, reaching values of 0.173 g cm−2 y−1. The mercury profile reflects the history of anthropogenic pollution in the estuary and perfectly describes the operation of the mercury-cell chlor-alkali plant, for production of NaOH, which began operations in 1980. The inventory of Hg was 2.42 ± 0.19 μg cm−2. These results contribute to the scarce regional database for pollutants and anthropogenic radionuclides in the Caribbean marine environment, particularly in relation to 239+240Pu.

► The NORM radionuclides were measured in ashes from a power plant (CPP) in Cuba.
► The annual effective dose measured was lower than the permitted dose for public.
► The ashes can be used as an additive for building materials.