Toxicity of oleate-based amino protic ionic liquids towards Escherichia coli, Danio rerio embryos and human skin cells

Abstract

Protic ionic liquids (PILs) have been widely employed with the label of "green solvents'' in different sectors of technology and industry. The studied PILs are promising for corrosion inhibition and lubrication applications in industry. Industrial use of the PILs can transform them in wastes, due to accidental spill or drag in water due to washing, that can reach water bodies. In addition, the handling of the product by the workers can expose them to accidental contact. Thus, the aim of this work is to evaluate the toxicity of PILs 2-hydroxyethylammonium oleate (2-HEAOl), N-methyl-2-hydroxyethylammonium oleate (m-2HEAOl) and bis-2-hydroxyethylammonium oleate (BHEAOl) towards Escherichia coli, zebrafish embryos, model organisms that can be present in water, and human skin cells. This is the first work reporting toxicity results for these PILs, which constitutes its novelty. Results showed that the studied PILs did not inhibit E. coli bacterial growth but could cause human skin cells death at the concentrations of use. LC₅₀ values for zebrafish eggs were 40.21 mg/L for 2HEAOl, 12.92 mg/L for BHEAOl and 32.74 mg/L for m-2HEAOl, with sublethal effects at lower concentrations, such as hatching retarding, low heart rate and absence of free swimming.

Keywords: Cytotoxicity; E. coli; Fish embryo toxicity; Protic ionic liquids; Toxicity.