RT Dissertation/Thesis
T1 A collection of insights on traditional phytoremediation approaches
T2 Una colección de ideas sobre enfoques tradicionales de la fitorremediación
A1 Novo, Luís Antonio Balreira
K1 2417 Biología Vegetal (Botánica)
K1 3209.07 Fitofármacos
K1 2417.08 Fitobiología
AB [eng] Soil metal pollution is a major threat for the environment and ultimately human health. Metals are extensively found scattered in rock formations, however industrialization and urbanization have critically enlarged the anthropogenic input of metals in the biosphere. Soils of mines, smelters, foundries, coal-burning power plants, and landfill sites are typically impaired by metal contamination. The production and use of pesticides, plastics, paints, coal ash, and industrial waste, and biosolids also contributes to the accumulation of metals in urban and agricultural soils. In addition to metals, soils are often subjected to stresses like salinity or drought. Salt stress in particular, is a growing concern afflicting nearly 25% of the soils in the world that consistently converts agricultural lands in saline lands. The individual and joint effects of metals, salinity and drought on plants include growth inhibition, leaf chlorosis, impairment of mineral nutrition, imbalance of water relations, and oxidative and photosynthetic damage, which strongly limits the presence of vegetation in polluted areas, increasing erosion and the migration of pollutants.Remediation of soils polluted with metals is essentially focused on the extraction or stabilization of the pollutants. Mechanical and physicochemical techniques are usually expensive and environmentally damaging, therefore the need for alternative low-cost and less harmful remediation methods has increased exponentially. Hence, techniques such as soil amendments and phytoremediation emerged as cheap and green solutions, whose individual or combined application has proven effective on the restoration of metal polluted soils.In this thesis, a number of papers depict various phytoremediation-based approaches to mitigate soil pollution. The contents can be condensed as follows: i) two waste-derived amendments, compost and technosol, were selected to assess their ability to promote the germination and growth of Brassica juncea in copper mine tailings. Both amendments, but especially compost, successfully allowed and enhanced the germination and plant growth. ii) Brassica juncea, a crop species well known for its tolerance to toxic levels of metals, was also studied for its potential for phytoremediation of copper mine tailings, and exhibited suitable features for phytostabilization and phytoremediation. iii) Considering the importance of the discovery of new species apt for phytoremediation, Salvia verbenaca was investigated due to the literature reports about its presence in mine areas and its antioxidant properties. The results suggested the fitness of Salvia verbenaca for phytostabilization of mine soils. iv) The synergistic effect of salt and Cd on the germination and early growth of a previously unreported variety of Brassica juncea was examined. The concurrent effects of Cd and salt did not significantly affect this variety, and the results suggest that mild concentrations of NaCl enhanced Cd uptake, revealing a good prospect for phytoremediation. v) The effect of salinity on the uptake of Zn with Brassica juncea was also studied. The species exhibited tolerance to the joint effect of both stresses, and moderate to moderately high NaCl concentrations increased the uptake and translocation of Zn to noteworthy harvestable amounts, making Brassica juncea an excellent candidate for phytoremediation of saline soils polluted with Zn. vi) The influence of soil moisture on phytoremediation of Cd and Zn with Brassica juncea was investigated. Higher soil moisture levels enhanced plant growth and the uptake of greater concentrations of these metals.
YR 2013
FD 2013-07-05
LK http://hdl.handle.net/11093/104
UL http://hdl.handle.net/11093/104
LA eng
DS Investigo
RD 02-dic-2024