Acute toxicity effects of a herbicide, Glycel on freshwater ciliates Paramecium caudatum, Oxytricha fallax and Blepharisma intermedium

The aim of this work was to assess the effect of Glycel on Paramecium caudatum , Oxytricha fallax and Blepharisma intermedium as this herbicide is mostly used in home, garden, and commercial applications. Acute toxicity tests were carried out for 3 hours and probit analysis is used to calculate the LC 50 values which were 63.09 ppm, 977.23 ppm and 1047.12ppm against to Paramecium caudatum, Blepharisma intermedium and Oxytricha fallax respectively. Paramecium caudatum was found more sensitive among test species, Blepharisma intermedium was moderate and Oxytricha fallax was found relatively tolerant. Behavioural manifestations like speedy egesting of food vacuoles, erratic swimming, moving to corners of cavity block and loss of movement coordination were observed during acute exposure. The various sub-lethal concentrations of Glycel were used to evaluate food vacuole, contractile vacuole activity and macronuclear aberrations tests and these tests proved that protozoan ciliates can act as alternative models to pesticide toxicity studies.