Effect of Parathion Exposure towards Green Microalgae Chlorella vulgaris on the Changes of Physicochemical Parameters in Water

Abstract

Agricultural activities has caused the release of pesticides such as parathion into the environment,
which threatened the freshwater ecosystem. Therefore, the objective is to observe for the changes
of physicochemical parameters (pH, conductivity and dissolve oxygen) caused on Chlorella
vulgaris due to parathion exposure. The cell count of C. vulgaris was done using hemocytometer
and this alga was exposed to different concentrations of parathion (1.000 mg/L, 0.100 mg/L, 0.001
mg/L, and 0.000 mg/L (negative control)). The values of each parameter were recorded before the
exposure and after 1 hour, 2 hours, 6 hours and 24 hours of exposure by using physicochemical
parameter. The results showed a fluctuation of all physicochemical parameters (pH, conductivity
and dissolved oxygen) values in the surrounding water at the first 5 hours of exposure and
decreased before reaching a plateau after the fifth hour of exposure. The reason of this phenomenon
could be due to the inhibition effects of parathion towards the photosynthesis activities of the algae
and thus lowering the physicochemical parameters. Therefore, C. vulgaris serves as a good
bioindicator of parathion pollution.