Evaluation of Acute Toxicity and Sub-Lethal Concentration of POEA on Fresh Water Fish Labeo rohita

Abstract

Polyoxyethylene amine (POEA) concentrations have been increasing in aquatic systems because of the widespread use of glyphosate herbicide. POEA is a glyphosate-formulation ingredient that facilitates the uptake and translocation of active ingredients into plant tissues. POEA has been reported to be more toxic to some aquatic organisms than glyphosate. Therefore, the present study was designed to evaluate the acute toxicity of POEA and the effects of its sub-lethal concentration on growth performance, haematological profile and bioaccumulation in the freshwater fish Labeo rohita. The LC₅₀ values of POEA were 10.01, 8.85, 6.75 and 5.65 mg L⁻¹ at 24, 48, 72 and 96 h, respectively, in Labeo rohita fingerlings. Exposure for 45 days to a sub-lethal concentration of POEA (0.56 mg L⁻¹) resulted in a significant reduction in growth and an increase in the feed conversion ratio in Labeo rohita at 15-, 30- and 45-day intervals. Haematological parameters, including red blood cells (RBCs), mean cell haemoglobin (MCH), haematocrit (HCT), haemoglobin (Hb) and platelets (PLT), decreased significantly (p < 0.05), whereas mean cell volume (MCV) and white blood cell (WBC) values increased significantly in POEA-exposed fish blood compared with normal fish at 15-, 30- and 45-day intervals. Furthermore, POEA accumulated most in the liver, followed by the gill, kidney and muscle. These findings indicate that low-concentration POEA exposure can adversely affect aquatic animals.