Assessment of the phytoremediation potential for Pb, Zn and Cu of indigenous plants growing in a gold mining area in Tanzania

Phytoremediation of soil has attracted much attention in recent years due to its multiple advantages such as maintaining the biological activity and physical structure of soils, being potentially inexpensive and visually unobtrusive, and providing the possibility of biorecovery of metals. Identification of native species for phytoremediation is a key to the success of the method. This study sought to identify plant species with potential for phytoremediation of soils polluted with lead (Pb), zinc (Zn) and copper (Cu). Soil and plants were collected and analysed for total metal concentration. Soil metal content range (mg kg-1) was 29.64-3457 for Pb, 37.53-6544.2 for Zn and 30.7-3625 for Cu. Of 19 plant species analysed, Sporobolus sp. proved to be a hyperaccumulator of Cu, Launea cornuta (Oliv & Hiern) O. Jeffrey, Tagetes minuta (L.) and Blotiella glabra (Bory) Tryon showed high potential for phytoextraction of Cu, and Dioscorea spp. (yam) and Stylochaeton natalensis Schott showed high potential for phytostabilisation of Cu. No hyperaccumulators of Pb and Zn were identified in the area, but Tephrosia candida and Tagetes minuta (L.) were identified as potential plants for phytoextraction of Pb and Conyza bonariensis (L.) Cronquist, Launea cornuta (Oliv & Hiern) O. Jeffrey, Tagetes minuta L.), Blotiella glabra (Bory) Tryon, Pteridium aquilinum (L.) Kulm and Polygonum setogulum A. Rich as potential plants for phytoextraction of Zn. Sphaeranthus africanus (L.) and Pteridium aquilinum (L.) Kulm showed potential for phytostabilisation of Pb and Stylochaeton natalensis Schott for phytostabilisation of Zn.© 2012 Copyright Mkumbo. S et al, licensee IPA.This is an open access article distributed under the Creative Commons Attribution License (2.0) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The electronic version of the article can be downloaded below.QC 20121016