Thesis Archive
Evaluation of the combined effects of pH and copper concertation on the copper phytoremediation potential of Dendrocalamus asper
BUENO, Brian Gerald C.
DAR, Lloyd Ross M.
MACANDILI, Romeo Antonio G.
Abstract:
Phytoremediation utilizes the hyperaccumulating ability of plants to uptake the contaminants in a growth matrix through its natural, biological, chemical, or physical activities and processes. Studies on phytoremediation by bamboos have been carried out by several investigators; however combined effects of initial contaminant concentration (Cu) and initial soil pH on the pollutant uptake of Dendrocalamus asper is not yet well established. When any of these parameters is too high or too low, copper uptake may be hindered due to speciation, competition, and copper toxicity. As such, D. asper was planted in soil at varying levels of copper concentration (14 mg Cu/kg dry soil and 42 mg Cu/kg dry soil) and pH levels (pH 5 and pH 7). The copper concentrations of the soil, roots, culm, and stems and leaves were analysed using AAS. For both initial copper concentration and initial soil pH, no direct effects were discovered regarding the copper uptake of D. asper. However, further investigations proved that the combined effects showed better correlation with D. asper’s copper uptake potential, in which the highest and lowest copper uptake were obtained from the 14 mg Cu/kg dry soil | pH 5 and 42 mg Cu/kg dry soil | pH 5 combinations, respectively. The optimal initial copper concentration and initial soil pH must be further identified to determine the best growth conditions of the bamboo. The kinetic behaviour was also determined by linear regression using the derived equations of rate law. It was found that samples at pH 7 and 14 mg Cu/kg dry soil obeys 0th order kinetics with an R2 of 0.9817. On the other hand, the combined effect of pH 5, 42 mg Cu/kg dry soil and pH 7, 42 mg Cu/kg dry soil follows 2nd order with 0.6613 and 0.6346, respectively. The poor kinetic fit of the samples at 42 mg Cu/kg soil could be the result of high copper toxicity to the bamboos. Lastly, samples with pH 5 and 14 mg Cu/kg dry soil exhibits decrease in Cu uptake in every order. One possible explanation for this is that maximum Cu uptake was already achieved in the 7th day and leakage of Cu ions occur at the following days.
Adviser:
BELO, Lawrence P.
GALVEZ, Ma. Cecilia D.