Triclosan: its occurrence, fate and effects in the Australian environment

摘要

Triclosan (TCS) is an antimicrobial agent used widely in household products such as soaps,nhousehold cleaners, cosmetics, sportswear, mouthwash and toothpaste. It is a bioaccumulativencompound known for its high toxicity to algae, daphnids, fish and other aquatic organisms. Weninvestigated its occurrence in effluents, biosolids and surface waters in Australia, as well as itsnfate in Australian soils and wastewater treatment plants (WWTPs), including the effects onnmicrobial processes in soils. The concentrations of TCS in 19 effluents ranged from 23 to 434 ng/Ln(median 108 ng/L) and in 17 biosolids from 0.09 to 16.79 mg/kg on dry weight basis (mediann2.32 mg/kg). TCS at concentrations of up to 75 ng/L were detected in receiving waters from fivencreeks affected by effluent discharge from WWTPs. The removal rate of TCS in five selectednWWTPs ranged from 72 and 93%, ascribed mainly to sorption onto sludge and biologicalndegradation. Biodegradation in a clay loam soil was noted with a half life of 18 days. Howevernthe half-lives under field conditions are expected to be very different. The studies on the effectnof TCS on soil microbiological processes showed that triclosan can disrupt the nitrogen cyclenin sensitive soils at concentrations Z5 mg/kg. In view of the recent risk assessment by thenAustralian regulatory agency NICNAS, there is an urgent need to assess exposure to TCS andnits effect on ecosystem health.