Triclosan

Short-term toxicity to aquatic invertebrates

Description of key information

Acutely very toxic for aquatic organisms

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

0.191 mg/L

Additional information

Three studies on the acute toxicity of Triclosan to aquatic invertebrates are available. In a study according to OECD guideline 202 Daphnia magna was exposed to the substance for 48 h in a static test system. Regarding the mobility of D. magna an EC50 of 0.191 mg/l was recorded (mean measured; Ciba-Geigy 1990). A second test on D. magna was set up according to U.S. EPA guideline No. 660/3-75-009. An EC50 of 0.39 mg/l (nominal) was determined after 48 hours of exposure. In a further test the correlation between acute toxicity and pH was tested. Ceriodaphnia dubia was exposed to Triclosan at four different pH (7.0, 7.5, 8.0, 8.5). The mortality of C. dubia was recorded after 48 hours. The LC50 values decreased with increasing pH. Following LC50 values were reported (measured): 0.13 mg/l (pH 7.0), 0.18 mg/l (pH 7.5), 0.24 mg/l (pH 8.0), 0.41 mg/l (pH 8.5) (Ciba-Geigy 1991).

The study by Ciba-Geigy (1990) was selected as key study as this study was performed with the preferred species Daphnia magna (REACH Regulation, Annex VII, 9.1.1) and showed the highest sensitivity at the tested pH range of 8.1 to 8.4. The study by Ciba-Geigy (1991) resulted in a similar EC50 at this pH range but was performed with a different species (Ceriodaphnia dubia). Only testing at a lower pH than the standard medium resulted in a higher sensitivity.

The acute toxicity of the metabolite methyltriclosan was determined according to OECD 202. The 48 -h EC50 was above the water solubility limit under test conditions of 0.18 mg/L (Ciba, 2006).

The following table gives an overview on the available reliable data on acute effects of Triclosan on aquatic invertebrates.

Reference	RL	Species	Exp.	Effect level	Value  (µg/L)	Nom./ meas.	Fw/ Mar.	Remark
Triclosan
Ciba-Geigy AG (1990). Proj. No. 262923	1	Daphnia magna	48 h	EC50	191	meas.	fw	mobility
Tamura et al. (2013)	2	Daphnia magna	48 h	EC50	180	meas.	fw	mobility
Harada et al. (2008)	2	Daphnia magna	48 h	EC50	260	nom.	fw	mobility
Peng et al. (2013)	2	Daphnia magna	48 h	LC50	330	nom.	fw	mortality
Wang et al. (2013)	2	Daphnia magna	48 h	LC50	338	nom.	fw	mortality
Procter & Gamble (1990). Rep. No. 38656	2	Daphnia magna	48 h	EC50	390	nom.	fw	mobility
Orvos et al. (2002)	2	Daphnia magna	48 h	EC50	390	nom.	fw	mortality
Ciba-Geigy Corp. (1991). Rep. No. 1011-0691-6278-132	2	Ceriodaphnia sp.	48 h	LC50	130	meas.	fw	mortality, pH 7.0
Ciba-Geigy Corp. (1991). Rep. No. 1011-0691-6278-132	2	Ceriodaphnia sp.	48 h	LC50	180	meas.	fw	mortality, pH 7.5
Ciba-Geigy Corp. (1991). Rep. No. 1011-0691-6278-132	2	Ceriodaphnia sp.	48 h	LC50	240	meas.	fw	mortality, pH 8.0
Ciba-Geigy Corp. (1991). Rep. No. 1011-0691-6278-132	2	Ceriodaphnia sp.	48 h	LC50	410	meas.	fw	mortality, pH 8.5
Wang et al. (2013)	2	Chironomus plumosus	96 h	LC50	2890	nom.	fw	mortality
Wang et al. (2013)	2	Limnodrilus hoffmeisteri	96 h	LC50	2046	nom.	fw	mortality
Wang et al. (2013)	2	Neocaridina denticulata sinensis	96 h	LC50	772	nom.	fw	mortality
De Lorenzo et al. (2008)	2	Palaemonetes pugio	96 h	LC50	154	nom.	Mar.	shrimp larvae
Kim et al. (2009)	2	Thamnocephalus platyurus	24 h	EC50	470	nom.	Mar.	mobility
Anselmo et al. (2011)	2	Psammechinus miliaris	72 h	EC50	78-89	nom.	Mar.	morphology of larvae
Hwang et al. (2014)	2	Strongylocentrotus nudus	72 h	EC50	286	nom.	Mar.	embryonic development
Cortez et al. (2012)	2	Perna perna	48 h	IC50	135	nom.	Mar.	embryo-larval development
Methyltriclosan
Ciba Specialty Chem. (2006). Rep. No.A34931	1	Daphnia magna	48 h	EC50	> 180	nom.	fw	mobility; EC50 above the solubility limit

Exp.: exposure duration; Fw.: freshwater; Mar.: marine water; Meas.: measured; Nom.: nominal; RL: Reliability