Sotida Boonsomboone. A selection of appropriate test conditions for whole effluent toxicity testing with juvenile nile tilapia (Oreochromis niloticus) . Master's Degree(Environmental Sanitation). Mahidol University. : Mahidol University, 2004.
A selection of appropriate test conditions for whole effluent toxicity testing with juvenile nile tilapia (Oreochromis niloticus)
Abstract:
Whole effluent toxicity testing is a procedure for an evaluation of effluent
toxicity. The study aimed to determine the toxicity of industrial effluent from
various test conditions on juvenile Nile tilapia (Oreochromis niloticus), and to
further select appropriate test conditions for whole effluent toxicity testing.
The results of 24-96 hr LC50 values of whole effluent toxicity testing of
every test condition were within a range of 35%-60%. This effluent was toxic to
Nile tilapia. When the toxicity of effluent from various test conditions were compared,
the different test conditions provided significant differences among 24-hr LC50,
48-hr LC50, 72-hr LC50 and 96-hr LC50 values (p-value < 0.05). The test conditions
significantly affected effluent toxicity. Furthermore, the effective factors were
studied, and it was found that temperature range and types of dilution water
significantly affected LC50 value in which toxicity increased with room temperature,
and receiving water caused a decrease in toxicity (p-value < 0.01). In conclusion,
the selected appropriate test conditions of whole effluent toxicity testing with
juvenile Nile tilapia (Oreochromis niloticus) were at control temperature : 25±1ºC,
tap water or receiving water, density 10 individuals : 200 ml at 24 hour exposure
time.
In addition to the findings of this study, using sensitive organisms from several
trophic levels, other endpoints and various types of effluent should be conducted
in further study for sound environmental management on the aquatic ecosystem.