3. Results
The percent mortality of Nile Tilapia exposed to Folidol 600 at
each 24 h interval is shown in Table 1. No deaths of the control animals
were observed. Fish mortality increased with the concentration
of methyl parathion and exposure period. Fish deaths
occurred at concentrations 5.0 mg Folidol 600/L after 24 h. Mortality
rates of 100% were observed after 72 h exposure to 10 mg
Folidol 600/L and also after 96 h at 5 mg Folidol/L. The median
lethal concentration (LC50) of Folidol 600 to Nile Tilapia was
17.82, 8.91, 4.00, and 2.7 mg L1 after 24, 48, 72 and 96 h of exposure,
respectively (Table 1).