Dibutyltin bis(2-ethylhexanoate)

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

2 µg/L

Assessment factor:

1 000

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

20 µg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

0.2 µg/L

Assessment factor:

10 000

Extrapolation method:

assessment factor

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

4.4 mg/L

Assessment factor:

10

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

165.7

Extrapolation method:

sensitivity distribution

Sediment (marine water)

Hazard assessment conclusion:

insufficient hazard data available (further information necessary)

Hazard for air

Air

Hazard assessment conclusion:

no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

insufficient hazard data available (further information necessary)

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

PNEC oral

PNEC value:

0.67 mg/kg food

Assessment factor:

30

Additional information

For derivation of the PNECaqua (freshwater), PNECaqua (marine water) and PNECaqua (intermittent release), the results of the Steger-Hartmann and Schmidt (1998) on the structural analogue DBTO were used. The value quoted for algae (>1.6 mg/L), although lower, was a greater than value set at the limit of solubility observed in the test system, at this concentration there was only 13% inhibition of growth rate and 26% inhibition of biomass indicating that the EC50 value for algae is above the saturation concentration. Steger-Hartmann and Schmidt (1998) is a reliable study (rated 2 according to the criteria set out by Klimisch, 1999) and gives the lowest actual EC/LC50 value observed in the key information for any of the ecotoxicology endpoints. The study examined toxicity of the test substance to Daphnia magna over a 48-hour exposure period and was conducted in accordance with OECD guideline for testing number 202. The standard assessment factors given in the European Chemicals Agency guidance document (R.10: Characterisation of dose [concentration]-response for environment) have been used to predict the above PNEC values from the results.

PNECstp has been derived based upon the Clarke (2010) study which provided a EC50 result of >1000 mg/l and a NOEC of 44 mg/L. The PNEC value has been derived from the NOEC. The standard assessment factors given in the European Chemicals Agency guidance document (R.10: Characterisation of dose [concentration]-response for environment) have been used to predict the PNEC values from the results.

PNECsediment and PNECsoil values have been estimated using the equilibrium partitioning method, in the absence of measured physico-chemical data, based on physico-chemical properties determined by expert judgement.

Conclusion on classification

Classification and labelling has been based upon the key information for the ecotoxicity endpoints available for the structural analogue DBTO. The results of these studies are as follows:

72 hour LOEC (fish): 3.1 mg/l (Steger-Hartmann T and Wendt B 1998)

48 hour EC50 (Daphnia): 2 mg/l (Steger-Hartmann, T. & Schmidt, M. 1998)

72 hour EC50 (algae): >1.6 mg/l (Steger-Hartmann T 1999)

It should also be considered that the substance does not meet the definition of a readily biodegradable substance (Hanstveit 2003) based on data available on the strutural analogue DBTO and knowledge of other organotin compounds.

The lowest of these results is the 72 hour EC50 for algae (Steger-Hartmann 1999) available on the strutural analogue DBTO, however this is a greater than the limit of solubility value observed in the test and is therefore not suitable for classification and labelling. The 48 -hour EC50 (Daphnia) value presented by Steger-Hartmann and Schmidt (1998) on the structural analogue DBTO, of 2 mg/l is suitable for use for classification and labelling and this meets the criteria under 67/548/EEC and EC Regulation 1272/2008 as follows:

67/548/EEC:

R50 and R53: Toxic to aquatic organisms and May cause long-term adverse effects to the aquatic environment.

EC Regulation 1272/2008:

Hazardous to the aquatic environment, Acute: Category 1 and Chronic: Category 1

It is considered suitable to apply classification and labelling based upon data availabnle on the structural analogue dibutyl tin oxide as it would seem likely that harmful effects to aquatic organisms are likely to be due principally to the tin content, gioven that similar effects have been seen in a variety of dibutyl tin compounds. Furthermore, the classification and labelling is considered to be the most severe labelling that can be applied under CLP for these endpoints.