Abstract

HERNANDEZ CORDOBA, OSCAR DARIO; CASTRO HERRERA, FERNANDO  and  PAEZ MELO, MARTHA. Mercury Bioaccumulation on Tadpoles of a Gold Mining Zone in Dagua River, Buenaventura, Valle del Cauca, Colombia. Acta biol.Colomb. [online]. 2013, vol.18, n.2, pp.341-348. ISSN 0120-548X.

Amphibians, particularly larval stages, are strongly sensitive to pollutants, so they have become useful indicators to assess how different human activities affect ecosystems. In this way, tadpoles were used as bioindicators in the Medio Dagua zone, in Zaragoza town, where mining has released pollutants into the Dagua River (mostly heavy metals). Using spectrophotometry by cold vapor atomic absorption, we measured total mercury concentrations in tadpoles of five species, with a sediment sample for each animal sample as an environment reference. The study was realized in two areas with different intervention levels, we report mercury concentration ranges from 0.07 to 0.24 µg/g for high impact zone and from 0.07 to 0.17µg/g for unknown impact zone, these levels do not exceed set limits used by local environmental authorities, however, is evident that bioaccumulation processes are developing in the area because organisms concentrations were always higher than those of the environment, in fact, significantly different (MW Utest, p = 0.001) therefore we propose the implementation of biomonitoring and bioremediation programs in the area, taking in consideration that tadpoles species used here, were mainly first order consumers, and when their mercury concentrations are incorporated into the food chain, these contaminant loads will produce biomagnification processes.

Keywords : Biomagnification; Contamination; Ecotoxicology; Tadpoles.

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