Tiered Approach for the Evaluation of Environmental Impacts of Triclosan on Aquatic Ecosystems

Ildikó Fekete-Kertész,Flóra Lukács,Zsófia Berkl,Mónika Molnár

doi:10.3311/ppch.12826

Abstract

The synthetic broad-spectrum antibacterial agent triclosan is one of the most commonly encountered emerging micro-pollutant in the aquatic environment due to the extensive use since 1968 mainly in cosmetics and household cleaning products and the partial elimination from wastewater. Its low water solubility, high sorption coefficient to organic matter, accumulation potential in fatty tissues and its low acute toxicity determined by conventional ecotoxicological tests suggest that its risk is more related to chronic effects requiring risk assessment based on more sensitive ecotoxicological methods. In this paper the short- and midterm ecotoxicological effects of triclosan were investigated using various test systems taking into account ecological complexity and environmental relevance. Acute single-species, simplified microcosm experiments and complex multi-species microcosm experiments were conducted with the determination of sublethal physiological and behavioral endpoints including the Daphnia magna heartbeat rate and feeding activity, the Heterocypris incongruens movement parameters and the Lemna minor chlorophyll content and root length. All physiological and behavioral endpoints indicated sensitively the adverse effect of triclosan in the concentration range of 4–25.6 µg/L. In some cases, responses of selected organisms in single-species laboratory tests did not correspond to those of the higher levels of test systems. Daphnia sensitivity increased with the level of the test system for all chosen endpoints except the heartbeat rate. Considering the varying ecological complexity of the assembled test systems, according to our results the exposure time and the different combinations of exposure routes were the most decisive parameters in terms of triclosan ecotoxicity and endpoint sensitivity.

Highlights

The adverse effects of aquatic micro-pollutants and their fate and behavior in the environment are widely studied recently [1, 2]
Triclosan is mainly released into the environment via the use of consumer products, which in most cases are externally applied to the human body, triclosan generally is not subjected to metabolic alteration [3]
3.1 Acute, single-species ecotoxicity tests The effect of triclosan on D. magna lethality and normal physiology was investigated applying 48 h exposure time

Summary

Introduction

The adverse effects of aquatic micro-pollutants and their fate and behavior in the environment are widely studied recently [1, 2]. Triclosan (5-chloro-2-(2,4-dichlorophenoxy) phenol) is a synthetic broad-spectrum antibacterial agent categorized as a halogenated aromatic hydrocarbon having phenolic, diphenyl ether and polychlorinated biphenyl substructures [3]. It has been used since 1968 as an antiseptic, disinfectant, and preservative in household consumer products (cosmetics, cleaning products) and in clinical settings incorporated on the surface of medical devices [4] with an estimated annual usage of 1000 t per year in the EU [5]. It has been detected ubiquitously in various aquatic environments such as lakes, rivers, coastal and estuarine waters, sediments, drinking water and even in living aquatic organisms [6,7,8] in ng/L–μg/L concentrations [9, 10]

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