Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Aquatic bioaccumulation

The following information is taken into account for any hazard / risk / bioaccumulation assessment:

DBT(2EHMA) has a LogKow of 3.4 which indicates a potential concern with regard to bioaccumulation. The EPIWIN BCFBAF v3.0 model calculates a BCF of 2043 using the simple regression model and the measured LogKow. However, the BCF calculated by the Arnot-Goban method using the same software is far lower at 6.5 as is that calculated using the CAESAR v1.0.0.11 model of 4.5.

No information is available for DBT(2EHMA), however it is possible to read across from the structurally similar compound DBTC. The following studies for DBTC have been submitted to address the bioaccumulation aquatic/sediment endpoint:

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.

Terrestrial bioaccumulation

No data available. However based on the low BCFs derived from the fish bioaccumulation study with the structurally similar substance DBTC at 4.3.1 above, there is considered to be a low risk of bioaccumulation.