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Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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Link to relevant study record(s)

Description of key information

BCF <100, dioctytin bis(2-ethylhexyl thioglycolate), OECD 305, EU Method C.13, Bouwman 2010

Key value for chemical safety assessment

BCF (aquatic species):
100 dimensionless

Additional information

The key study was performed in line with GLP and in accordance with standardised guidelines OECD 305 and EU Method C.13. The study was performed on the surrogate substance dioctyltin bis(2-ethylhexyl thioglycate); like all octyltin compounds, this is anticipated to hydrolyse very rapidly in water. The fish in the study are therefore expected to have been exposed to the same organotin species that would occur if the test had been performed using the registration substance as the test essentially measures the dioctyltin species.

The bioconcentration of the test material in rainbow trout exposed to 0.25 and 2.5 µg/L for 30 days in a flow-through system was determined to be 1294 and 99 respectively based on measured dioctyltin. The high BCF value found at the 0.25 µg/L concentration was due to the limitations in the sensitivity of the analytical methods employed in the study and could not be further improved. Based on the result found at the highest concentration tested, the BCF is at least less than 100 and therefore the substance is not expected to bioconcentrate.

The study was performed to a good standard with a sufficient level of detail to assess the quality of the results. As such it was assigned a reliability score of 2 due to being used in a read across capacity using the principles for assessing data quality as set out in Klimisch (1997) and considered suitable as an accurate reflection of the test material.

Two disregarded studies, Recommendation for classification dossier (2005) and IUCLID Dataset (2006), on the read across material n-dioctyltin oxide were included for completeness as both are in the public domain. The studies were deemed unsuitable as the result was derived using calculation software not validated for organometallic substances and reported in a secondary source.