Metallic Pollution Around Reghaïa Lake: Tolerance Assessment of Oxalis Pes-caprae L. as Remediative Plant

Abstract

The Reghaïa Nature Reserve (Algeria) comprises a freshwater lake surrounded by natural soils covered by spontaneous vegetation with a habitat for wildlife. It is exposed to 3 mains sources of pollution i.e. an industrial zone, agricultural lands and the urban area. Abnormal high levels of metallic trace elements (MTEs) have been already reported in lake’s water and natural topsoil. In the present study, we explore the tolerance and phytoremediation capacity of Oxalis pes-caprae L., growing spontaneously on Reghaïa lake’s bank, toward Pb, Zn and Cd, the 3 main metal pollutants from anthropogenic activities. Sampling was carried out over 4 months, for Oxalis pes-caprae L. plants and rhizosphere soils, harvested in 3 sites along a gradient of proximity to lake’s water. Firstly, we estimated the degree of contamination of the sampled sites by Pb, Zn and Cd and we determined soils parameters which influence metals distribution in soil and their absorption by O. pes-caprae L. roots. Secondly, we examined the distribution and the accumulation of Pb, Zn and Cd within O. pes-caprae shoots and roots. The results revealed that Pb and Cd were the main soil pollutants and that O. pes-caprae L. adopted different remediation strategies such as an exclusion strategy for Pb in soil and a phytoextraction strategy for Cd.