Arsenic in Argentinean aquatic organisms in an ecologic context

MARDIROSIAN M.; VODOPIVEZ C.; PÉREZ C.A.; PÉREZ R.D.; VENTURINO A; BONGIOVANNI G.A.

Aveiro

Simposio; 9th International Symposium on Environmental Geochemistry; 2012

ISEG

Arsenic is an abundant toxic metal in our environment and is mobilized by water, which is theprimary route of exposure for plants and animals, including humans. Throughout Argentina, theAs is a natural contaminant of many groundwater and some river beds where many species andabout 4 million people are exposed to arsenic concentrations much higher than 0.010 mg/L.Although arsenic toxicology is well described for mammal models and humans, studies in otherenvironments such as those affecting aquatic organisms are rare in our country. Argentiniantoad (Rhinella arenarum) is an interesting biomarker of ecological impact of freshwatercontamination because, as most of the amphibians, are in close contact with water during theearly stages of life and have contact with land as adults. So, they may serve as a critical link inbiotransferance of arsenic within both, aquatic and terrestrial communities. On other hand, filterfeeders specie as krill and bivalves are an important element of the food chain within marineecosystems. For that, arsenic accumulated by R. arenarum, Diplodon chilensis (river´s clams),Mytilus edulis (mussels), and Euphausia superb (Antarctic krill) was measured by X-rayFluorescence Spectrometry in grazing incidence geometry (SR-TXRF) at the D09B-XRFbeamline from the Brazilian Synchrotron Light Laboratory (LNLS). Argentinian toad oocytes,obtained by in vitro fecundation, were incubated in Ringer solution containing 0 (control) or 1μg/ml As up to larval life stage. Oxidative damage was also determined along development.Clams, mussels and krill were collected in the ?Río Negro, Patagonia? river, ?Las Grutas,Patagonia? beach and ?Isla 25 de Mayo, Antártida? coast, respectively. We found up to 54 μg ofAs per gram of dry weight of in toad larvae accompanied by decreased antioxidant capacity.The highest As concentration found in analyzed samples was 2,88 μg/g of dry weight inmussels. In an ecologic context, the As accumulation in these organisms, may have importantimplications and should be further investigated.Work funded by FONCyT, CONICET, Argentina and ABTLuS, Brazil.