THESIS APPROVAL

PAHs abolished positive phototaxis in nauplii of barnacle Balanus amphitritniveus at
concentrations ranging from about 0.14 ppm dimethylnapthalene. The studies on
physiological changes including growth, reproduction and larval development also
have been observed. Laughlin and Neff (1979) reported that duration of larval
development to the megalops stage of mud crab Rhithropanopeus harrisii was
decreased by exposure to sublethal concentrations of naphthalene. Ott et al. (1978)
reported that marine copepod Eurytemora affinis was statistically significant
reduction in life span, brood size, and total number of nauplii produced when exposed
to 29 d 10 µg/l naphthalene. Woodward et al. (1983) found that cutthroat trout
Oncorhynchus clarki exhibited significant reductions in survival and growth at the
concentration between 1 and 17 µg/l total naphthalene. The study on mud crab Scylla
serrata showed that naphthalene causes disturbance in the normal physiology of the
crab at a concentration of 10 mg/l, including increase of the consumption of oxygen,
decrease of respiratory enzymes in hepatopancreas, ovary and gills (Vijayavel and
Balasubramanian, 2006a). Moreover, the biochemical constituents and all marker
enzymes in this crab species were decreases in hepatopancreas and ovary, while in
hemolymph, were increased (Vijayavel and Balasubramanian, 2006b).
1. Criteria for Selection
Use of Aquatic Oligochaete in Sediment Toxicity Tests
Test species used for evaluation of sediment toxicity and bioaccumulation of
anthropogenic contaminants should meet certain criteria to fit satisfactorily for
sediment bioassay. These criteria include ecological relevance, wide geographical
distribution, taxonomic relation to indigenous animals, good availability and ability
to assess chronic endpoint, incorporation of all relevant routes of exposure, tolerance
of sediment characteristics and suitability for bioaccumulation assays (Giesy and
Hoke, 1989). Oligochaetes fulfill most of the criteria and have been successfully
employed in bioassays (Kukkonen and Landrum, 1994). Due to their true sedimentingesting
behavior, they are excellent test organisms for studying bioaccumulation of
hydrophobic sediment-bound contaminants. Ingestion of contaminated particles and
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