Soil variables that determine lead accumulation in Bidens pilosa L. and Tagetes minuta L. growing in polluted soils

MARIA JULIETA SALAZAR; JUDITH HEBELEN RODRIGUEZ; CAROLINA VERGARA CID; CECILIA ELENA BERNARDELLI; EDGARDO RUBÉN DONATI; MARÍA LUISA PIGNATA

GEODERMA

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2016 vol. 279 p. 97 - 108

0016-7061

Toxic metal soil pollution is one of the most serious environmental problems, with phytoextraction being an ecologicaland inexpensive potential solution to recuperate soil functionality. This emergent technology has producedgood results for many elements, but phytoextraction has not been as successful for lead as for otherpollutants. This research aimed to evaluate several factors that could be determinant on Pb uptake by the accumulatorplants Bidens pilosa and Tagetes minuta. Topsoils (bulk and ryzospheric) and plants were collectedaround a former Pb smelter, and sequential extractions of Pb, Cu and Zn, organic matter content, electrical conductivity,pH, and texture were measured in soils. Also, bacterial diversity in soil was determined by the denaturinggradient gel electrophoresis (DGGE) technique. The Pb, Cu, and Zn concentrations in soil extractions andplants (leaves, stem, and root) were quantified by T-XRF in Synchrotron, Brazil. Our results demonstrated thatPb uptake from polluted soils and translocation to aerial tissues by two Asteraceae species are related not onlyto the traditional soil parameters, but even more importantly to the Zn and Cu concentrations in plant andsoils. In addition, the soil bacterial biodiversity also affects the Pb uptake by plants. In this study, we proposethe total translocation factor (TTF) to evaluate the phytoextraction efficiency, which is given by the ratio oftotal extraction of Pb in aerial organs and roots, instead of using the Pb concentrations alone