Endocrine disruption effect of chronic exposure to mefenamic acid on aquatic organisms

Abstract

Pharmaceuticals and their metabolites have attracted an increasing concern in aquatic environments and biota. Alterations in the endocrine system in humans or wildlife are of special interest because these alterations could eventually lead to changes in reproductive fitness. In spite of frequent detection of mefenamic acid, the hazards associated with long-term exposure to MFA have seldom been investigated. We have determined the acute and chronic toxicity of MFA on several aquatic organisms, including two cladocerans, Daphnia magna and Moina macrocopa, and a teleost, Danio rerio. The 48 h acute median effective concentration (EC50) of D.magna and M. macrocopa was 17.16 mg/L and 2.93 mg/L, respectively. In 21 d chronic toxicity test, D. magna showed significant changes in reproduction related characteristics after the exposure to MFA. In the early life stage test using D. rerio, significant decrease of larvae survival was observed at 1 mg/L of MFA. In addition, vitellogenin gene expression and VTG protein level were significantly reduced at the highest concentration of MFA. The result of this study indicates that this pharmaceutical may have a potential effect on survival, reproduction and growth of the aquatic organisms. The pharmaceutical studied here has been frequently detected in ambient water worldwide, but the effect concentrations are a few orders magnitude greater than those occurring in the ambient aquatic environment.