Po levels and distribution in different environmental compartments from a coastal lagoon. The case of Briozzo lagoon, Uruguay.

This paper presents the levels and distribution of Po in different compartments of a coastal lagoon on the east coast of Uruguay (South America). Activity concentrations of Po have been obtained in different matrices, such as water, superficial sediments, clams (Diplodon sp.), freshwaters snails (Pomacea sp.), zooplankton, and fishes (Jenynsia sp.), collected at different points of the lagoon and during several sampling campaigns. In addition, the organic matter content of the sediment was determined to study the variation of Po along the lagoon. The activity concentrations of Po in the water samples are in the range between 1.1 ± 0.2-3.5 ± 0.4 mBq/L while in the sediment samples vary between 17.1 ± 1.4 and 540 ± 12 Bq/kg, DW. In the case of biota, the ranges obtained were 182 ± 5-265 ± 6 Bq/kg, DW in clams and 134 ± 4-1245 ± 16 Bq/kg, DW in snail samples. A good correlation of Po with the organic fractions of the sediment was observed (r = 0.8798, p-value < 0.001), being obtained high values for the distribution coefficient Kd (10 -10). In the biota samples, a clear difference was observed in the Po concentration values in both species, mainly due to the different feeding habits of both aquatic organisms, as it is reflected in the associated concentration ratios (CR). In this paper, a good set of results of Po, Kd, and CR have been obtained in different matrices, enhancing the limited archives available for modelers concerning these parameters for Po and freshwater systems.