The macrophytes Potamogeton pusillus L. and Myriophyllum aquaticum (Vell.) Verdc. as potential bioindicators of a river contaminated by heavy metals

Abstract

To evaluate the Myriophyllum aquaticum and Potamogeton pusillus macrophytes as indicator organisms of heavy metal pollution in biomonitoring studies of the aquatic ecosystem, the aim of this studywas to determine the Co,Cu, Fe, Mn, Ni, Pb and Zn accumulation in leaves of the those species and the possible relationship to water pollution by thesemetals. Surfacewater, sediment and plantswere collected at 10 sampling sites of the Ctalamochitariver (Argentina). Cooper and Pb concentrations exceeded the limits established for the protection of aquatic life defined by Argentina Legislation (Cu: 2.0 μgL−1, Pb: 2.0 μgL−1) and international norms (Cu: 1.6 μgL−1, Pb: 2.5 μgL−1) in surface water, while Cu and Zn exceeded the limit for ecological screening levels (Cu: 31.6 mgkg−1, Zn: 121.0 mgkg−1) in sediment. Heavy metal concentrationswere found to be higher downstream of Río Tercero city in water and sediments samples, probably related to the contribution of pollutants from the effluent discharge of the city. Both species revealed a high capacity to accumulate heavy metals in its tissues, in areas of the river with higher heavy metals values in the abiotic compartments. Particularly, high accumulation of Co, Cu, Ni and Zn in P. pusillus correlatedwith their concentrations in sediments and Co, Cu, Mnand Zn accumulation in M. aquaticum correlated with the concentrations of these metals in water. These macrophytes reflect spatialvariations of metals in water and sediments of the Ctalamochita river; therefore they are of potential use as heavy metal bioindicators of river pollution.