Abstract:
A study was conducted to determine acute and chronic effects of herbicidecyhalofop
butyl on the survival and reproduction rate of Moina macrocopa in a
laboratory study. It is found that cyhalofop butyl concentrations that cause 50%
mortality (LC50) after exposure for 24 and 48-h were 1.91 and 0.34 mgL-1,
respectively. While non-observable effect concentration (NOEC) was found to be 0.8
μgL-1• Moina macrocopa exhibited 100% mortality at day 14 and day 12 after being
exposed to cyhalofop butyl at 0.4 μgL-1 and 8 μgL-1, respectively. Reproduction rate
was greatly reduced by about 41.2% at 0.4 μgL-1
while approximately 60% at 8 μgL-
1
as compared to control organisms throughout 14 days. If environment
concentration of cyhalofop butyl is controlled and does not exceed 0.4 μgL-1
application of this herbicide is unlikely to cause adverse effect on this cladoceran
population in aquatic agroecosytem.
