International Journal of Aquaculture, 2013, Vol.3, No.10, 43
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45
Figure 2 Trend of pH value with respect to effulent concentration
Figure 3 Trend of conductivity with respect to effulent concentration
1.2
Behavoural Response
Based on visual observation during data recording. the
fish were exhibited erratic swimming behouvral responses
particularly when the concentration of textile effluent
increased. As the experiment progressed the fish were
become weakere and weaker with some color changes
arround the operculum and fins particularly doursal
fins. However. normal behavour were observed on the
fish stocked in control and 10% (v/v) outlet effuelnt
concentration. and had similar patern.
1.3
Toxicity Evalution
The effects of inlet and outlet textile effluent
concentrations on percentage mortality of the fish for
96
hrs exposure time is demonestrated by Figure 4. As
indicated by this figure. mortality was not observed on
the fish stocked in control and 10% (v/v) outlet
effluent concentration. while maximum percentage
mortality was observed on the fish stocked in higher
effluent concentrations particularly for 100%. (v/v)
inlet effluent concentration. The 96hrs LC
50
was also
extrapoleted to be 30.5% (v/v). and 3.279 as ATU for
inlet. and 71.5% (v/v) and 1.399 as ATU for outlet
from the quaratic graph of percentage mortality
verces effluent concentration (Figure 5). The safe
concentration of effluent for both inlet and outlet
wastewater is set to be 3.05% (v/v) and 7.15% (v/v),
respectively. Similarly, the efficiency of removal of
toxicants was 57.33% (v/v) (Table 2).
Figure 4 A 96hrs percentage mortalty of the test organisms
exposed to different effluent concentrtions
Figure 5 A 96hrs lethal concentration (LC
50
)
determination of
Oreochromis niloticus