Mercury distribution in estuarine wetlands and salt-marshes from argentina: an overview

DE MARCO, S.G.; BOTTÉ, S.E.; MARCOVECCHIO, J.E.

Belém, Brasil

Workshop; INTERNATIONAL WORKSHOP ON HEALTH AND ENVIRONMENTAL EFFECTS OF MERCURY – IMPACTS OF HG ON SOUTH AND CENTRAL AMERICA; 2003

National Institute for Minamata Disease and Universidade Federal do Pará

Total mercury contents from both abiotic and biological compartments within several estuarine wetlands and salt-marshes from Argentina have been fully studied since the 80´s. By the way, the assessment of Hg occurrence in surface sediments, suspended particulate matter and crab, fish or hallophyte species from Mar Chiquita Coastal Lagoon, Bahía Blanca estuary or Samborombón Bay (in La Plata river estuary) are included in the present study. Biological tissues were mineralized according with an own modification of the method described by Uthe et al.(1970) while sediments and SPM were treated following Marcovecchio et al.(1988) and APHA (1992). Analytical determination of total mercury has been carried out through flameless atomic absorption spectroscopy with cold vapor technique (CV-FAAS). In all cases analytical quality were checked against international reference materials. During 80´s Hg contents within sediments and SPM as well as in edible fish species from Bahía Blanca estuary have shown to be high, and the large industrial nucleous located in the northern margin of the estuary was opportunely identified as the main source of this metal. Nevertheless, a permanent monitoring programme developed since 1996 and up to now has demonstrated that Hg concentrations were significantly lower than those of 80´s. On the other hand, both Mar Chiquita coastal lagoon and Samborombón Bay have presented intermediate mercury in their abiotic and biological compertments. In both cases the possible occurrence of remote sources of this metal was considered. Both mercury bioaccumulation and biomagnification processes were evaluated in the studied estuaries, as well as the potential qualification of estuarine foodstuffs for human consumption.