Assessment of native species from Argentina for phytoremediation of lead polluted soils around a lead smelter

M. J. SALAZAR; M. L. PIGNATA

Portland, Oregon

Conferencia; International Phytotechnology Society Conference "Putting Plants to Work where we Live, Labor, Breathe, and Play"; 2011

International Phytotechnology Society

The heavy metal contamination of soils is considered one of the greatest environmental concerns at the moment, and has a great impact considering the fact that humanity is not sustainable without good quality soils. This type of pollution implies complex and costly measures to undertake due to the high residence time of metals in soils with the possibility of groundwater migration. By reason of its property of permanence, the adverse conditions persist long after removing the source of pollution. In this context, remediation of heavy metal polluted soils represents a technological challenge for both industries and government institutions. Despite being a method used in many parts of the world, phytoremediation studies are scarce in Argentina, especially those referring to heavy metals. On the other hand, there are no antecedents in the study of native species with this aim in Argentina. In the present work, we focused on soils affected by elevated lead concentrations in an agricultural and residential area surrounding a lead smelter plant that recycled batteries which operated between 1984 and 2005 in Bouwer, province of Córdoba, Argentina. We also studied the lead phytorremediation potential of certain native plants for polluted soils. The aims of this research work were to study the distribution of lead in soils around the lead smelter plant, differentiating the labile and total metal concentrations in soils, and to assess the plant species growing there as potential phytorremediators. Lead concentration in leaves, shoots and roots was determined in thirteen species collected in ten sites with different lead concentration in soil. Two native species, Tagetes minuta L. and Bidens pilosa L., showed interesting values of lead concentration in leaves, 380,5 μg/g and 100,6 μg/g respectively, in a site with 1500 μg Pb /g soil. In the same sampling site, Sorghum halepense (L.) Pers., a non native species, showed high lead concentration in roots, 1406,8 μg/g; but the values for leaves and shoots were lower than 6 μg/g. Tagetes minuta L. and Bidens pilosa L. are species with a phytoremediation potential for lead polluted soils and they should be studied deeply in order to enhance the lead uptake rate. Sorghum halepense (L.) Pers. may be an appropriate species for immobilizing lead in soils.