Elsevier

Chemosphere

Volume 46, Issues 9–10, March 2002, Pages 1485-1489
Chemosphere

Triclosan, a commonly used bactericide found in human milk and in the aquatic environment in Sweden

https://doi.org/10.1016/S0045-6535(01)00255-7Get rights and content

Abstract

High levels of the commonly used, effective bactericide Triclosan was found in three out of five randomly selected human milk samples. It was also found in the bile of fish exposed to municipal wastewater and in wild living fish from the receiving waters of the three wastewater treatment plants.

Introduction

Triclosan (Fig. 1) is a very common antibacterial agent used in a number of products as diverse as toothpaste, detergents, household sponges, plastic cutting boards, socks and underwear. The main manufacturer is Ciba-Geigy that uses the names Irgasan® DP 300 and Irgacare® MP. Impregnated fibres and polymers have names like Ultra-Fresh®, Amicor®, Microban®, Monolith®, Bactonix® and Sanitized®. Triclosan is a stable, liphophilic compound (log Kow=4.8) able to form low chlorinated dioxins on incineration and under the influence of sunlight, under certain circumstances even more highly chlorinated isomers, as demonstrated by Kanetoshi et al., 1988a, Kanetoshi et al., 1988b.

Triclosan is active against both gram-positive and gram-negative bacteria and its mechanism of action and structural binding has recently been elucidated by a number of researchers (McMurry et al., 1998; Levy et al., 1999; Heath and Rock, 2000). The enzyme ENR (enoyl–acyl carrier protein reductase) involved in the bacterial lipid biosynthesis is effectively inhibited by triclosan. It has not yet been shown toxic to mammals, but it is toxic to water living organisms such as fish (LC50, rainbow trout=0.35 mg/l) and Daphnia magna (EC50=0.39 mg/l) and especially to algae (EC50=1.5μg/l) (Ciba, 1998). Very little is known about sublethal effects in fish living in the recipient. The use of this type of phenolic antibacterial substances was abandoned in most hospitals in Sweden several years ago, since they were considered unnecessary in practical use (Myrbäck, 1999). In the late 1970s it was shown that one of these substances, hexachlorophene used in soaps, was absorbed through the skin and caused damage to the nervous system of infants (de Groot et al., 1994).

In order to investigate human exposure for triclosan, five randomly selected samples of human milk were analysed using GC/MS. Triclosan occurrence in the aquatic environment was examined by exposing rainbow trout in cages in the receiving water outside a small wastewater treatment plant and in tanks to treated wastewater from two large plants. Wild living fish was also caught in the receiving waters of the three plants. Bile fluid from the exposed fish was analysed for triclosan. As it was found impossible to get information on what active ingredient an antibacterial product contains, other that toothpaste and cosmetics, a number of products on the Swedish market was collected in co-operation with the Swedish Consumer Agency and analysed by GC/MS.

Section snippets

Chemicals and reagents

Ethyl acetate SupraSolv and hexane LiChrosolv, were obtained from Merck, methyl-t-butyl-ether HPLC-grade came from Rathburn, β-glucuronidase (101200 β-glucuronidase units/ml and 290 sulfatase units/ml) from Sigma, acetic anhydride pro analysi from Prolab. Formic acid, Na2CO3, H2SO4, HCl and KOH were all pro analysi from Merck. Fluoranthene and β,β-binaphthyl with purity >99% were purchased from Larodan. Triclosan (Irgasan DP300) was a gift from Ciba-Geigy.

Consumer products

Bicycle shorts, socks, cutting boards,

Wastewater treatment plants

Three municipal wastewater treatment plants were investigated. Gråbo is a small conventional plant situated in the south west of Sweden. It uses no anaerobic digestion, receives mainly domestic wastewater from approximately 3500 persons and is not connected to any large industries. Ryaverken is a big modern plant on the Swedish west coast treating sewage water from the second largest town in Sweden, Göteborg. The water is subjected to both anaerobic and aerobic digestion. Henriksdal is a big

Consumer products

Most of the investigated consumer products with antibacterial treatment contained triclosan. One household sponge was treated with dichlorophene, three WC-blocks with chlorophene and two shoe insoles had an ingredient which still remains to be identified.

Human milk

High levels of triclosan were determined in three out of five individual samples of human milk, in one sample as high as 300μg/kg lipid weight (Table 2).

Fish exposure to treated wastewater

In all fish bile samples, high levels of triclosan was found: in the bile fluid of rainbow

Conclusion

The commonly used, effective bactericide triclosan contaminate human milk, survives several microbial degradation steps in the wastewater treatment process, enters the aquatic environment where it is bio available to fish.

Acknowledgements

We thank Prof. Lars Förlin for valuable discussions, Cajsa Wahlberg at Stockholm Vatten for help and discussions, Claes Öster and Rolf Wolfe at Henriksdals reningsverk, Göran Svernbäck at Gråbo reningsverk, Peter Balmér and Annette Johansson at Ryaverken for help, Daniel Berggren and Hans Bärring for catching the perch outside Henriksdal, Helena Nilsson and Gunilla Rosén at the Consumer Agency for help with collecting various antibacterial items. We thank MISTRA and Bohuskustens

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