Registration Dossier

Data platform availability banner - registered substances factsheets

Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Environmental fate & pathways

Endpoint summary

Currently viewing:

Administrative data

Description of key information

Additional information

Aquatic bioaccumulation


This study was waived on the basis that it was not technically feasible to conduct.


Following decision number CCH-D-0000003196-74-05/F, it was attempted to conduct the bioaccumulation in aquatic species study (OECD 305) required under point 9.3.2. of Annex IX of Regulation (EC) No. 1907/2006. It was determined however that it is not technically feasible to conduct this study, due to the inability to develop a substance specific analytical method that could be used to monitor the substance during the performance of the test.


 


A literature search was conducted in order to determine the available data on the registered substance. No appropriate data that was judged to be both reliable and relevant to the material itself was uncovered.


 


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


DBTO can be considered to have low solubility in water and octanol. Although it was not technically feasible to determine a partition coefficient, the visual assessment of solubility in both water and n-octanol was found to be less than 1 mg/L.


In the OECD SIDS report for Dibutyltin oxide (5.12.2008) BCFWIN v2.15 (EPI Suite, US EPA 2000) was used to estimate a BCF value of 63720 L/kg. However in the report it is emphasised that this result should be used with caution as the model was not validated for chemicals that contain metals in their molecular structure.


In addition, a recalculation with BCFBAF v3.01 (EPI Suite, US EPA 2011), the updated program of BCFWIN, was performed and a BCF of 38360 L/kg wwt (based on the regression method) and a BCF of 574 for the upper trophic level (based on Arnot-Gobas method) were estimated. However once again, EPI Suite clearly states that inorganic and organometallic chemicals generally are outside the domain.


The program estimates the BCF of an organic compound using the log octanol-water partition coefficient (Kow). However, the Log Kow has also been estimated using EPI Suite, which as stated above is not validated for this type of compound.  The BCF estimate for this compound is therefore calculated from a QSAR which is itself based on a value determined using a QSAR.  In both instances, the QSARs used are not validated for this type of compound and the reliability of this estimation is highly questionable.


In the absence of any experimental data for DBTO, it is possible to refer to data on the similar compound DBTC.  This reference is considered appropriate as the species of concern with regard to bioaccumulation will be the DBT moiety.  In a BCF study with either compound, analysis would be for the same species (the DBT moiety or total tin).


 


In aquatic bioaccumulation studies DBTC had BCFs of 5 to 135. These are significantly below 2000.


 


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 is available. However, based on the low BCFs derived from the fish bioaccumulation study with the structurally similar substance DBTC above, there is considered to be a low risk of bioaccumulation.