CONICET | Buscador de Institutos y Recursos Humanos

This study presents for the first time valuableresults of lead (Pb) accumulation in zooplankton from asouthwestern Atlantic temperate estuary, the Bahı´a Blancaestuary, one of the most important and industrialized coastalenvironments of Argentina. It considers Pb concentrationsin zooplankton organisms as well as in the dissolved andparticulate phases. These fractions were analyzed onaccount of their important role in the biogeochemical cyclesof trace elements in estuarine environments. In addition,the major physicochemical variables, i.e., nutrients, andpigment concentrations, and zooplankton composition andabundance, were also considered to understand Pb levels inthe above-mentioned fractions. Samplings were performedfrom March to December 2005 with a bimonthly frequencyand comprised a study area with stations located nearindustrial settlements and other stations a few kilometers farfrom these points. The results of the physicochemicalvariables and nutrients and pigments agreed with historicvalues for the estuary and did not present any evidence ofabnormalities. Dissolved Pb presented a mean concentrationof 2.15 ± 0.46 ug L-1, whereas particulate Pb presenteda mean concentration of 13.52 ± 3.07 ug g-1 dryweight (dw). In the mesozooplankton, represented bycopepods, the mean concentration was similar to the particulatefraction (13.38 ± 4.41 Use of biomarkers in resident organisms as a tool for environmental monitoring in a cold coastal system, Tierra del Fuego Island  ug g-1 dw), whereas in themacrozooplankton, represented by mysids, it was lower(9.81 ± 1.89 Use of biomarkers in resident organisms as a tool for environmental monitoring in a cold coastal system, Tierra del Fuego Island  ug g-1 dw). Thus, Pb concentrations wererelatively high in the dissolved and particulate phases.Moreover, zooplankton accumulated important concentrationsof this metal, which was mainly incorporated throughsuspended particulate matter (SPM). The source of Pb in allof these fractions is related to the industry discharges aswell domestic sewage located near the sampling stations.Finally, through these results, it was possible to show theimportance of zooplankton and SPM in the biogeochemicalcycle of Pb as well as the interaction between these fractionsin an estuarine and anthropogenic environment, such as theBahía Blanca estuary.