Date of Award

1-1-2000

Thesis Type

Masters

Document Type

Thesis

Divisions

Institute for Advanced Studies

Department

-

Institution

Universiti Malaya

Abstract

Nine freshwater microalgal species of Malaysia, Chlorella vulgaris (isolate 001). Scenedesmus sp. (isolate 039), Moug,wlia sp. (isolate 069). l llothrix sp. (isolate 071). Ch/ore/la sp. (isolate 078), Ankistrodf!snms co11vo/11tus (isolate IO I), Chlorococuum sp. (isolate 110), Synechococcus sp. (isolate 075). Euglena sp. (isolate 058), and including two species Oocystis polymorpha UTEX 1645 (isolate 169) and Ankistrodesmus arcuatus UTEX LB 1379 (isolate 170) from the UTEX Collection, Texas, were used in 96 h single heavy metal (Cd, Co, Cr. Cu, Fe, Mn and Zn) exposure static studies for preliminary toxicity test. This was done by incubating the microalgae in a range of metal concentrations in Bold Basal Medium (BBM) in multiwell plates. Of these species Ankistrodesmus convolutus Corda (isolate No. 101) was selected for further toxicity and bioaccumulation tests. Toxicity tests were conducted to investigate the toxic effect of Cd. Co, Cr, Cu, Fe, Mn and Zn on the growth of A. c:onvoluws. Results from the toxicity tests showed that A. convo/11111.r is tolerant to most of the heavy metals. The order of toxicity in A. convolutus based on 96 h IC 50 and IC 25, are Zn= Mn > Cu > Cd > Cr > Co > Fe. A. convolutus was most sensitive to Fe (IC,o = 0.52 mgL-1) and most tolerant to Mn (IC 50 = 16.14 mgL -1). Ankistrodesmus convolutus was exposed to different concentrations of seven metals (Cd, Co. Cr, Cu, Fe, Mn and Zn) to observed patterns of heavy metal uptake (bioaccumulation) in short-term test. Four main metal accumulation patterns were observed in this study: Pattern: rapid metal uptake during the first hour of exposure and followed by a gradual release; Pattern 2: continuous uptake appears during the entire hour of exposure till an equilibrium level; Pattern 3: rapid uptake during the first hour exposure and followed by a gradual release till equilibrium level is reached ; Pattern 4: alternating uptake and release of metal. In general, maximum uptake occurred in the first hour of exposure, followed by a further gradual uptake, or gradual release, or an alternating uptake - release pattern. Metal bioaccumulation increased with increasing concentration of metal in the medium. Cells in logarithmic growth were more active in metal bioaccumulation than cells at stationary growth.

Initial

snms

Additional Information

Dissertation (M.A) -- Institute for Advanced Studies, Universiti Malaya, 2000

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