2-ethylhexyl 10-ethyl-4,4-dioctyl-7-oxo-8-oxa-3,5-dithia-4-stannatetradecanoate

Bioaccumulation: aquatic / sediment

Key value for chemical safety assessment

BCF (aquatic species):

99 dimensionless

Additional information

The study procedure described in Bouwman, 2010, report was based on the OECD guideline No. 305, 1996.

The final target concentrations were 0.25 and 2.5 µg/l (based on water solubility and detection limits of the analytical methods used). The uptake phase lasted for 30 days, during which samples were taken from the test medium and from the fish.

 

Analyses were based on both dioctyltin (DOT) and monooctyltin (MOT). Results were based on DOT, due to the fact that MOT-concentrations were below the Limit Of Quantification (LOQ) for the target concentration of 0.25 µg/I. The mean concentrations of DOT were 0.19 ± 0.048 µg/l and 2.6

±

0.35 µg/I at target concentrations of 0.25 and 2.5 µg/I, respectively. The measured concentrations varied within the ± 20% window of the mean concentration at the target concentration of 2.5 µg/l but not at the target concentration of 0.25 µg/I.

 

Analyses of the concentrations of both DOT and MOT in fish tissues during the 30-day uptake phase showed measured concentrations that were always below the Limit of Quantification, i.e.< 0.25 mg/kg.

Since the concentrations of both DOT and MOT in fish were constantly below the LOQ during the uptake phase, a depuration phase was not considered to be significant. Therefore, the bioconcentration test was terminated after 30 days of exposure. In addition to the analytical work already performed on tin species, fish samples taken after 30 days of exposure were analysed on total tin.

 

The mean BCF-values based on dioctyltin at target concentrations of 0.25 and 2.5 µg/I were1294 and 99, respectively. The mean BCF-values based on total tin at target concentrations of 0.25 and 2.5 µg/I were 178 and 58, respectively.

 

The high value found at the target concentration of 0.25 µg/I was in fact due to the analytical methodology limit, which could not be further improved. Nevertheless, total tin analysis supports the fact that tin species do not bioaccumulate in fish tissues.

 

Based on the result found for the highest target concentration of 2.5 µg/I, the BCF is at leastless than 100 and therefore the substance does not bioconcentrate.