THESIS APPROVAL

2. Chemicals and Reagents
2.1 Naphthalene (C10H8, 99% purity, AR grade, Ajax Finechem, Australia)
2.2 Acetone (C3H6O, AR grade, J. T. Baker, USA)
2.3 Cyclohexane (C6H12, AR grade, Lab-Scan, Thailand)
2.4 Hexane (C6H14, AR grade, Fisher Chemicals, USA)
2.5 Acetonitrile (CH3CN, HPLC grade, Lab-Scan, Thailand)
2.6 Ethanol (CH3CH2OH, AR grade, Merck, Germany)
2.7 Sodium sulfate (Na2SO4, AR grade, Ajax Finechem, Australia)
2.8 Magnesium chloride (MgCl2, AR grade, Ajax Finechem, Australia)
2.9 Glutaraldehyde (C5H8O2, EM grade, EMS, UK)
2.10 Osmium tetroxide (OsO4, EM grade, EMS, UK)
2.11 Phosphate buffer (pH 7.2)
2.12 Olive oil
2.13 Deionized water
1. Test Organism and Sediment
1.1 Worms
Methods
Limnodrilus hoffmeisteri was manually collected in April 2006 from Chao
Phraya river bank located at Tok road waterside, Bangkorlaerm district, Bangkok,
Thailand (Figure 10). High densities of oligochaetes were found among debris within
5 m of the river edge. A large quantity of sediment containing worms was scraped
with small shovel several times. The sediments were washed through 0.5 mm sieve
with regional spring water. Worms were transported to the laboratory and carefully
sorted under stereo microscope. Before setting up the experiments, worms were
classified according to Brinkhurst and Jamieson (1971), and the identification was
also confirmed by Christer Erseus (pers. comm.), the expert on zoological systematics
of Class Clitellata (Phylum Annelida), from University of Gothenburg, Sweden, using
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