| 1. |
- Mkumbo, Stalin, et al.
(författare)
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Assessment of the phytoremediation potential for Pb, Zn and Cu of indigenous plants growing in a gold mining area in Tanzania
- 2012
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Ingår i: International Journal of Ecology and Environmental Sciences. - : Integrated Publishing Association. - 0377-015X .- 2320-5199. ; 2:4, s. 2425-2434
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 2. |
- Mkumbo, Stalin
(författare)
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Development of a Low Cost Remediation Method for Heavy Metal Polluted Soil
- 2012
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- High concentrations of heavy metals in the soils have potential long-term environmental and health concerns because of their persistence and accumulation tendency in the environment and along the food chain. This study was aimed at studying the feasibility of heavy metals removal from the soil using plants naturally growing in the surroundings of selected polluted sites in Tanzania and soil application of the sorbent materials zeolite and autoclaved aerated concrete (AAC). The results showed thatSporobolus sp. is a hyperaccumulator of Cu. Four other species, Launea cornuta (Oliv & Hiern) O. Jeffrey, Tagetes minuta (L.), Sporobolus sp. and Blotiella glabra (Bory) Tryon showed high potential for phytoextraction 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, while 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 were identified as potential plants for phytoextraction of Zn. The result from sorbent experiments showed that both materials had a potential for remediating metal polluted soils. The AAC had a higher removal capacity for both Zn and Pb than zeolite. The removal capacity of zeolite and AAC in a mixed metal experiment (Pb and Zn) showed a little difference in the sorption capacity of AAC and Zeolite for Pb and Zn respectively. Speciation of the metal in soil shows that the major part of the metal was associated with firmly attached component of the metal in the soil. Compared with the total metal concentration analysed, the available component accounted for 13-39% for Zn and 31-39% for Pb. It can be suggested to co-remediate polluted soils using reactive sorbent nodules and hyper-accumulating plant species. Identification of the best combinations and designs remains the subject of future research.
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| 3. |
- Renman, Gunno, et al.
(författare)
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Active removal of lead and zinc from polluted soil by in situ sorption to mineral nodules
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Heavy metal pollution of soils is a worldwide problem. This study evaluated the capacity of autoclaved aerated concrete (AAC) and zeolite to adsorb zinc (Zn) and lead (Pb) in an artificially polluted soil. Rectangular shaped nodules of AAC and zeolite of 2 cm width, 4 cm length and 2.5 cm height were buried in plastic boxes of soil for 5 months and the soil was irrigated with distilled water every 3 days. The results showed that both AAC and zeolite had good potential for removal of heavy metals from polluted soils, although AAC showed a higher adsorption capacity for Zn than did zeolite. A large proportion of the metals was firmly bound to the soil particles and was not readily released on irrigation with water in the experimental set-up. Compared with the total metal concentration analysed, the available component accounted for 13-39% for Zn and 31-39% for Pb. This might be the reason why the adsorbent materials could only accumulate a fraction of the total metal concentrations.
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