Growth Inhibition Effect of Organophosphate Pesticide, Monocrotophos on Marine Diatoms

Abstract

The growth inhibition effect of organophosphate pesticide, Monocrotophos on Odontella mobiliensis and Coscinodiscus centralis was investigated. Growth of diatoms was reduced on exposure to low concentrations (2 to 8 mg/L) of Monocrotphos (MCP) up to 48 hrs afterwards growth was normalized, but higher concentrations have seized the growth completely. The IC50 of MCP was 7.2±0.3 mg/L and 17.7±3.9 mg/L on O. mobiliensis and C. centralis respectively. The No Observable Effect Concentration (NOEC), Low Observable Effect Concentration (LOEC) and Sub Chronic Values (SChVs) were estimated to be 0.5±0.04, 0.95±0.06 and 0.69±0.03 mg/L on O. mobiliensis and 1.05±0.07, 2.13±0.11 and 1.5±0.09 mg/L on C. centralis. The results of present study ascertained that the MCP is moderately toxic to diatoms and the safe concentration of MCP for diatoms was determined to be less than 0.5 mg/L.