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Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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Description of key information

The following studies have been submitted in support of the argument for omission of further testing for the bioaccumulation aquatic/sediment end point:
No information is available for DBT (2-EHMA), however it is possible to read across from the structurally similar compound DBTC.
Tsuda et al (1986). Bioconcentration of Butyltin Compounds by Round Crucian Carp. Toxicological and Environmental Chemistry Vol. 12, pp. 137-143.
Tsuda et al (1988). BIOCONCENTRATION AND METABOLISM OF BUTYLTIN COMPOUNDS IN CARP. Wat. Res. Vol. 22, No. 5, pp. 647-651, cited in Walterson et al (1994). KEMI report: Mono and Di-Substituted Organotins Used as Plastic Additives - Volume 1: Environmental Hazard Assessment. Report no.: 11/94. Owner company: THE SWEDISH NATIONAL CHEMICALS INSPECTORATE.
All studies have been allocated a Klimisch score of 4. The studies were performed on dibutyltin dichloride, which is similarto the substance in question, a read-across approach was therefore considered suitable for assessment of the bioaccumulation potential of the substance.

Key value for chemical safety assessment

Additional information

The two studies provided in support of omitting further testing were Tsuda et al (1986) and The KEMI report (Waterson et al (1994). The Tsuda et al (1986) study was conducted to non-standard methods, and the parameters of the study were not comparable to those required for accurate assessment of this data requirement. Both studies were assigned reliability scores of 4 (not assignable), this was based on methodological deficiencies and areas lacking in detail in the reporting of the study by Tsuda et al (1986).The KEMI report (Waterson et al (1994), is a comprehensive review of mono and di-substituted organotins and encompasses a later report by Tsuda (Tsuda et al 1988). Both studies, though not sufficient for assessment indicated that the potential for bioaccumulation in aquatic species is low.

As bioaccumulation is considered to be unlikely further testing was ommitted in accordance with column 2 of REACH Annex IX. Bioaccumulation in Aquatic Species does not need to be conducted as the chemical safety assessment concluded that the substance is of no immediate concern to the environment. The available data are adequate for classification and labelling purposes and PBT assessment, so no further testing is required. Also direct and indirect exposure of the aquatic compartment is unlikely.This is further supported by the anticipated low log Kow (<3) which also points to the conclusion of a low potential for bioaccumulation.