Lead uptake of water plants in water stream at Kiteezi landfill site, Kampala (Uganda)

Abstract

The purpose of this study was twofold: (i) to quantify the lead (Pb) uptake by two water plants reeds (Phragmites australis) and papyrus (Cyperus papyrus) in water stream at Kiteezi landfill site, Kampala (Uganda) and (ii) to compare the two species in Pb uptake downstream. As such, leachate samples were collected at the inlet and outlet of the waste water treatment plant (WWTP) at Kiteezi landfill site. A total of 6 plant samples of both plant species, P. australis and C. papyrus, were picked from three different sites at intervals of 10, 20 and 30 m taken from the exit point of the WWTP, as the reference point. All samples were taken to the laboratory for analysis in a cool container. The concentration of Pb in the samples was measured using the atomic absorption spectrometer (AAS), Perkin Elmer Model. The obtained data was analyzed using descriptive statistics and two-way Anova. The results showed that there was no significant difference (P > 0.05) in the mean Pb content up taken by both plants (reeds and papyrus). Significant quantities of Pb were present in the plants in the range of 1.68 to 5.46 mg/100 g. The removal efficiency of the plants was found to be 12.4 times higher than WWTP. The highest concentrations of Pb were found downstream at a distance of 30 m away from the reference point. Although, the plants were generalized as having equal uptake levels, the two species had different mechanisms with reeds being accumulators and papyrus being excluders. Therefore, reeds are preferable phytoremediators since when harvested by cutting as practiced by some communities in Uganda, the Pb can easily be removed from the environment.

Key words: Lead-uptake, excluders, accumulators, phytoremediation, leachates and Kiteezi.