The effect of environmental exposure to zinc in an ecosystem without point sources: a sublethal approach

SILVIA DE MARCO; ORNELA BELTRAME,; JORGE MARCOVECCHIO

Salvador (Recife)

Congreso; Environmental Health 2001 Conference – Resetting our Priorities; 2011

The concentrations, distribution and spatial / temporal variations of zinc (both dissolved and particulate) were fully studied in estuarine water, surface sediments, suspended particulate matter (SPM) and organisms within Mar Chiquita coastal lagoon, in Argentina’s Atlantic littoral. This coastal lagoon is a natural reserve (in the UNESCO’s Man & Biosphere Programme framework), and –even a large agricultural / livestock productive area encompasses this environment– point sources of heavy metals (i.e., industries, sewage discharges, harbours, etc) are not included there. Nevertheless, high Zn concentrations have been opportunely determined in the above mentioned matrixes: between non detectable and 1224 µg/L (dissolved); ~4 and 16900 µg/g (SPM); ~12 to 40 µg/g in total sediment and ~50 to 236 µg/g in the finest grain fraction (< 63 µm) of sediment; and, mean values of ~49 ± 10 µg/g in specimens of the burrowing crab (Neohelice granulata) recognized as a key species within the studied environment. Considerig the described environmental scenario, different toxicity bioassays were carried out in order to determine the range of Zn values producing deletereous effects (including lethality) on the the key species of the coastal lagoon, and the potentiality of toxicity events within the system concerning the detected Zn levels within the different compartments of this complex ecosystem