Assessing the effect of glyphosate on the shrimp Palaemon adspersus: Acute toxicity and biomarker responses

Abstract

Glyphosate, a widely used agricultural herbicide, poses a risk of aquatic contamination. This study assessed the acute toxicity of glyphosate in the shrimp Palaemon adspersus (Decapoda, Palaemonidae). The sublethal (LC10 and LC25) and lethal (LC50 and LC90) concentrations were estimated after 24 and 96 hours of exposure. The compound was added to rearing water at LC25 and LC50– for 96 hours during the exposure phase (24, 48, 72, and 96 hours). Shrimp were then transferred to clean seawater and collected during the recovery phase (24, 48, 72, and 96 hours). Enzymatic activities in shrimp heads and flesh fragments were measured for acetylcholinesterase, gluthatione S-transferase, and malondialdehyde, followed by lipid quantification. Toxicological data indicated the toxicity of glyphosate against shrimp, exhibiting a dose-response effect. Lethal concentrations LC10, 25, 50, 90 were 1.15, 1.25, 1.35, 1.59 mg/L after 24 hours and 0.99, 1.06, 1.14, 1.31 mg/L after 96 hours. Two-way ANOVA during the treatment phase showed significant (P < 0.05) effects of glyphosate concentration and treatment time on all the biomarkers. During the recovery phase, shrimp compensated for herbicide effects, demonstrating acute toxicity that caused oxidative stress and neurotoxic effects at sublethal concentrations. Careful control is recommended to minimise the negative impacts on non-target aquatic organisms.

Keywords

• decapoda; herbicide; glyphosate; toxicity tests; biomarkers; biochemical responses.