ABSTRACT

Ten Clarias gariepinus fmgerlings of mean weight 12.76±6.33 g and mean length of 8.41±1.39 cm S.E were randomly selected and respectively introduced into each of the following concentrations of laundry effluent; 0, 25 ppm, 50 ppm, 75 ppm and 100 ppm during a static bioassay for 96 hrs (4 days) experiment. The 96 hrs LC₅₀ of laundry effluent to fingerlings of Clarias gariepinus was 33.88 ppm with the upper and lower limits of 37.20ppm and  30.86ppm respectively. The threshold value (safe level) was calculated as 25.12 ppm. Six samples of laundry effluent were collected from one of the laundry outfits located in the Eastern sector of Umuahia and analysed for heavy metals; Zinc, Lead, Nickel, Copper, Cadmium and Iron using Atomic Absorption Spectrophotometer (AAS). The results got from the analysis of laundry effluents samples for the heavy metals listed above showed that zinc was with highest concentration in all the months with 3.5922mg/l, 4.6505 mg/l, 4.4485 mg/, 4.0272 mg/l, 4.2604 mg/l, 4.1464 mg/I while lead (Pb) emerged as the least with the concentration of 0.0997 mg/l, 0.1293 mg/l, 0.1362 mg/I, 0.1597 mg/l, 0.1015 mg/l and 0.1744 mg/l for the duration of six months (i.e. April — September). The physico-chemical parameters of the experimental water were also monitored during the period of the investigation. a Furthermore, the opercula ventilation beat and the pectoral fin beat frequencies of Clarias gariepinus fingerlings exposed to different concentration of laundry effluent were determined and their values recorded accordingly. The results showed that at the inception of the experimental test, the test fish were found to have an increased breathing while the breathing decreased at the terminal point of the experiment which resulted in eventual death. The toxicant auto delivery bioassay experiment of laundry effluent indicated that the toxicant led to the mortality of the fish in relation to time interval since the physico-chemicai parameters of experimental water did not vary significantly (P<0.05). ><0.05)