Heavy metal concentrations in different compartments of Andean lakes of Northern Patagonia

Abstract

Trace elements, including heavy metals, can reach the aquatic ecosystems from natural or anthropogenic sources. Heavy metals are amongst the most important environmental contaminants due to its toxicity, permanency and its tendency to bioaccumulate in aquatic organisms. Because of those factors it is important to study these elements to assess the environmental risk they represent to the aquatic ecosystems of the region. The objective of this work is to present the most relevant results concerning the levels of heavy metals in different compartments of lakes in Northwestern Patagonia. These results allow the analysis of trace element concentrations in sediment cores, suspended sediments, water, plankton, macroinvertebrates and fish muscle and liver. In general, heavy metal concentrations in the different compartments are similar to those found in other freshwater ecosystems around the world. The exceptions are mercury and silver, which show enrichment in the last decades in the upper sections of the sediment cores and higher Ag concentration in sites near human settlements. In some cases, mercury concentrations in sediment and Ag and selenium in biota are similar to those foundin ecosystems affected by moderate levels of contamination. Although bioaccumulation of trace elements was observed in fish muscle, in any case the concentrations are above the limits allowed for human consumption by SENASA. This review will help to identify reference values for trace element concentrations and to discern patterns of anthropogenic impacts through time which will help future monitoring of the lacustrine environments of the region.liver. In general, heavy metal concentrations in the different compartments are similar to those found in other freshwater ecosystems around the world. The exceptions are mercury and silver, which show enrichment in the last decades in the upper sections of the sediment cores and higher Ag concentration in sites near human settlements. In some cases, mercury concentrations in sediment and Ag and selenium in biota are similar to those foundin ecosystems affected by moderate levels of contamination. Although bioaccumulation of trace elements was observed in fish muscle, in any case the concentrations are above the limits allowed for human consumption by SENASA. This review will help to identify reference values for trace element concentrations and to discern patterns of anthropogenic impacts through time which will help future monitoring of the lacustrine environments of the region.