CONICET | Buscador de Institutos y Recursos Humanos

Trace metals have proven to be significantly hazardous pollutants in aquatic environments, even at very low concentrations. Mar Chiquita Coastal Lagoon covers an area of approximately 60 km2, and drains a tributary watershed of 10000 km2, where a very important agricultural land use is developed. Besides, agriculture has been identified as a source of heavy metals via fertilizers and pesticides. Although chemical and biological processes are common to most estuaries, the distributions of trace metals greatly vary among them, depending on environmental factors such as hydrodynamics, residence times, mixing patterns and transport processes. The present work deals with the analysis of dissolved and particulate heavy metals (Cd, Pb, Cu, Zn, Ni, Mn, Cr) of high environmental significance, and focusses on the relationships between both forms and with the suspended particulate matter (SPM). Significant inter-relationships between the concentrations of several metals, indicated similar sources and/or similar geochemical processes controlling their levels. Unlike results obtained in other estuaries, no relationships among metals with SPM were observed. The partition coefficient of all metals was very variable. The annual average of hydrographic parameters presented no evidence of abnormality in their distributions. This could support the fact that no gross change in the chemical speciation of trace metals occurred. A comparison with other estuaries and coastal areas indicated a great input of heavy metals. These results suggest that Therefore, the human activities -specially intense agriculture- within the drainage basin of Mar Chiquita Coastal Lagoon, may cause metal pollution.