Effects of a POEA surfactant system (Genamin T-200^®) on two life stages of the Pacific oyster, Crassostrea gigas

Abstract

Surfactants used in herbicide formulations are generally considered inert with no toxic effects on animals. Polyethoxylated tallow amines (POEAs) are non-ionic surfactants used in many herbicide formulations to promote the penetration of the active matter into plant cuticles. The present study aimed to assess the toxicity of a POEA surfactant system, the Genamin T-200^®, on two larval stages of the Pacific oyster, Crassostrea gigas. The embryotoxicity of Genamin T-200^® was quantified after 36 hr of exposure, considering both arrested development and abnormalities in D-shaped larvae. The ability of pediveliger larvae to metamorphose was studied after 24 hr exposure to Genamin T-200^®. According to the European toxicity classification, the present results suggest that Genamin T-200^® could be considered very toxic to embryo larval development, with an EC₅₀ of 262 µg/l, and toxic to metamorphosis processes with an EC₅₀ of 3,027 µg/l. The high toxicity of glyphosate-based formulations compared to the active ingredient and its by-product appears to be due primarily to surfactants.