Sensitivities of seven algal species to triclosan, fluoxetine and their mixtures

Ran Bi,Lei Mu,Lingtian Xie,Liping Hou,Wenhua Liu,Hongxing Chen,Dan Li,Xiangfeng Zeng,Jiaxi Tang,Ping Li,Agnes Bouchez

doi:10.1038/s41598-018-33785-1

Abstract

Increasing release of pharmaceuticals and personal care products (PPCPs) into aquatic ecosystems is a growing environmental concern. Triclosan and fluoxetine are two widely used PPCPs and frequently detected in aquatic ecosystems. In this study, the sensitivities of 7 algal species from 4 genera to triclosan, fluoxetine and their mixture were evaluated. The results showed that the inhibitory effect on algal growth (EC50-96h) of triclosan varied with 50 times differences among the 7 algal species. Chlorella ellipsoidea was the least susceptible species and Dunaliella parva was the most sensitive species to triclosan. The inhibitory effect of fluoxetine was less variable than triclosan. Slightly higher toxicity of fluoxetine than triclosan was shown in the 7 tested algal species. No consistent pattern of the effects from mixture of triclosan and fluoxetine was observed among the 7 algal species and among the 4 genera. Additive effects of the mixture occured in 4 species and antagonistic effects in the other 3 species but no synergistic effect was detected. The algal species might show some sign of phylogenetic response to triclosan, as evidenced by the wide range of differences in their sensitivity at the genus level. This study provides important data which could be beneficial for biomonitoring programs on the ecological risk (algal species diversity) of these two chemicals.

Highlights

Pharmaceuticals and personal care products (PPCPs) are a large group of chemicals including antibiotics, hormones, anti-inflammatory drugs, disinfectants, insect repellants, and UV-filters, etc.[1,2]
The no-observed effect concentrations (NOEC) in the seven algal species ranged from 6.2 μg/L in S. quadricauda to 100 μg/L in C. pyrenoidosa and C. ellipsoidea (Table 1)
Metabolic pathway of triclosan may include biodegradation, hydroxylation, methylation, gluocosylation and xylosylation in different organisms, where the major pathyway for triclosan is biodegradation in C. pyrenoidosa, and biotransformation in S.obliquus[51,52]. Other factors, such as algal species, culture medium, pH, light intensity would affect the inhibitory effect of triclosan on the growth of algae[15,19,36,53,54]

Summary

Introduction

Pharmaceuticals and personal care products (PPCPs) are a large group of chemicals including antibiotics, hormones, anti-inflammatory drugs, disinfectants, insect repellants, and UV-filters, etc.[1,2]. Triclosan (5-chloro-2-(2,4-dichlorophenoxy)phenol) is a synthetic antimicrobial chemical and applied in a variety of consumer healthcare products, soaps and plastics[9] It has been used as a disinfectant for several decades[10]. Fluoxetine has a logKow value of approximately 4.5 in surface water and is hydrolytically and photolytically stable in water. It can be rapidly dissipated from water phase as a result of adsorption in the particulate matter or sediment in natural water[29]. Algae have proved to accumulate many pollutants from the water which can be transferred to species at higher trophic levels[38,39,40]. Dunaliella are salt tolerant species found in salt lake and marine environment and are often used as model test species for marine and estuary environments[44,45]

Objectives

Methods

Results

Conclusion