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Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Bioaccumulation is possible. Triclosan is not B/vB (BCF < 2000)

Additional information

Bioaccumulation of Triclosan is possible. The available studies indicate that high accumulation rates in fish are achieved during relatively short time periods. However the observed loss during depuration was comparably fast and high.

In a weight-of-evidence approach, it can be shown that all of the available studies have merits and limitations. Therefore, all available data (in vivo, in vitro and estiamted) must be considered to assess the bioaccumulation potential of TCS with a higher certainty than based only on the studies by Ciba-Geigy and Schettgen.

From the study by Ciba-Geigy (1991) a BCF of 2532 was selected as key value. Taking into account all available information summarised in the comparison of both studies (BASF SE, 2012), it can be concluded that there is a much higher level of uncertainty in the BCF results from the Schettgen et al. (1999) study than in the results from the Ciba-Geigy (1991) study. Especially the uncertainty on test media preparation, the high variation in the recovery of Triclosan in the fish tissue along with the exceeding concentration of methanol in the test raises serious doubts on the validity of the Schettgen et al. (1999) study.

In combination with other available experimental and estimated data, it can be concluded that TCS has a BCF below 2000 and is thus not B/vB.

A bioaccumulation study in earthworm was performed according to a draft OECD guideline (adopted as OECD 317, 2010). Test material was radio-labeled (13C). Test concentrations were 01. and 1.0 µg/g (nominal) and were analytically verified. The BAF was determined at steady state and as kinetic value (normalised to lipid fraction) :

- BAF steady state: 52.1 at 0.1 µg/g, 31.3 at 1.0 µg/g

- BAF kinetic: 0.59 at 0.1µg/g, 1.4 at 1.0 µg/g

Elimination was observed during the 21 -d depuration phase.

Considering the similarity in the Koc and Kow values and the predominance of the unionized parent compound in the terrestrial environment, the potential for bioaccumulation in the earthworm based on present knowledge is low.