Browsing by Author "Sangu, George"

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    Study on the phytoremediation of arsenic (as) contaminated soils in Geita
    (University of Dar es Salaam, 2014) Sangu, George
    The study on phytoremediation of arsenic contaminated soils was carried out in Geita low land areas that receive effluents from gold mining. Screening of plant species with ability to accumulate arsenic using systematic random sampling revealed that Chloris pycnothrix is a potential arsenic hyperaccumulator. The species was found to accumulate 42.4 mg/kg in frond tissues with negligible amounts of arsenic in roots under field conditions .Laboratory testing of the species against hyperaccumulator criteria, C. pycnothrix qualified for high plant biomass, easy germination, rapid growth and translocation factor above one. This study found that amending the soils with organic matter, pH and mycorrhizae improved C. pycnothrix biomass increased the species tolerance to arsenic toxicity, improved arsenic uptake by the species and translocation of arsenic from the root tissues to the frond tissues. Single factor analysis of variance at P < 0.05 showed that there were significant differences in biomass, arsenic uptake and translocation when amended with organic matter > 5 %, amended to pH > 8 and mycorrhizae amended at all levels of arsenic subjected to the plant.These findings suggest that C. pycnothrix is a potential hyperaccumulator and that amending contaminated soils with organic matter, pH and mycorrhizaae can improve hyperaccumulation. The other species i.e. Cyperus papyrus, Paspalum auriculata, Oryza sativa, Ageratum conyzoides, Cynodon dactylon and Miscanthus vioolecium were classified as arsenic excluders although they can be explored for hyperaccumulation of other metals than arsenic.