THESIS APPROVAL
THESIS APPROVAL
THESIS APPROVAL
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(1997) said that naphthalene is moderately hydrophobic with log Kow of 3.34, and<br />
this chemical may thus have a tendency to adsorb to particulate matter and<br />
accumulate in biota if the period of exposure is no longer. From these documents, it<br />
is suggested that naphthalene body burden may depends on the period of time<br />
exposure. With an estimation by 96 h test period using in this study, it could be said<br />
that naphthalene remained in the test sediment tends to transfer and then<br />
bioaccumulate in the tissue of L. hoffmeisteri.<br />
105<br />
The route of uptake of a chemical to an organism will have a major<br />
influence on the bioaccumulation of many chemical contaminants. Aquatic animals<br />
may be exposed to such contaminants via several routes, such as, the food by<br />
ingestion, through the overlying water, by pore water, by the respiratory system, and<br />
by dermal absorption. The latter two routes of entry is called skin absorption for<br />
some invertebrate species which do not have very specialized respiratory organs<br />
(Conrad et al., 2002). James and Kleinow (1994) stated that the different uptake route<br />
would affect bioaccumulation. Several previous studies have suggested that pore<br />
water is the most important route of uptake for infaunal benthic organisms, including<br />
oligochaetes (Roesijadi et al., 1978a; Oliver, 1984; Knezovich and Harrison, 1988).<br />
The chemical was accumulated via pore water or via direct contact of integument with<br />
sediment particles and then entered to the body of oligochaetes (Leppanen and<br />
Kukkonen, 1998b). Although these animals received their body burden both through<br />
interstitial water and sediment ingestion, the low molecular weight PAHs, such as<br />
naphthalene (128.18), is more available to such organisms that mainly accumulate<br />
from pore water due to only 2-ring PAH with hydrophilic character. This is agreed<br />
with the work of Lyes (1979), Landrum (1989), Weston (1990) and Meador et al.<br />
(1995). In comparison with highly hydrophobic PAHs, strongly associated with<br />
particulate matter are accumulated in deposit-feeder as a result of sediment ingestion<br />
(Lyes, 1979; Landrum, 1989; Boese et al., 1990; Schrap and Opperhuizen, 1990;<br />
Weston, 1990; Meador et al., 1995). Chemicals with greater hydrophobicity are more<br />
tightly associated to solids which in turn increase the importance of ingested material<br />
in accumulation (Leppanen and Kukkonen, 2000a). This is in agreement to previous<br />
studies conducted with other oligochaete species. Leppanen and Kukkonen (1998b)