2-ethylhexanoic acid, molybdenum salt

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

0.42 mg/L

PNEC freshwater (intermittent releases):

0.163 mg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

0.042 mg/L

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

42.5 mg/L

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

7.41 mg/kg sediment dw

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

0.74 mg/kg sediment dw

Hazard for air

Air

Hazard assessment conclusion:

no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

PNEC soil

PNEC value:

1.2 mg/kg soil dw

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

no potential for bioaccumulation

Additional information

Read-across approach

In the assessment of the environmental fate, ecotoxicity and toxicity of 2-ethylhexanoic acid, molybdenum salt (CAS: 34041-09-3), a read-across approach from data for the metal (molybdenum) and the organic anion (2-ethylhexanoate) is followed. This read-across strategy is based upon the observation that upon dissolution in aqueous media, 2-ethylhexanoic acid, molybdenum salt completely dissociates and only is present in its dissociated form, i.e., as molybdenum and 2-ethylhexanoate ions. Data on the environmental fate, ecotoxicity and toxicity for both transformation products (molybdenum and 2-ethylhexanoate) together can therefore be combined in an additive approach to predict the corresponding properties of 2-ethylhexanoic acid, molybdenum salt.

A detailed justification for the read-across approach is added as a separate document in section 13 of IUCLID.

Upon dissolution and dissociation of 2-ethylhexanoic acid, molybdenum salt into molybdenum and 2-ethylhexanoate, both ions will each show the proper (bio)degradation, bioaccumulation and partitioning behaviour in the environment, as reported for the corresponding ion. The environmental fate and behaviour for molybdenum and 2-ethyl hexanoate is predicted to be clearly different from each other, resulting in a different relative distribution over the environmental compartments (water, air, sediment and soil). Because the relative exposure to both constituent ions is hence predicted to be different from the original composition of 2-ethylhexanoic acid, molybdenum salt, data for the ecotoxicological properties of this substance tested as such are considered less relevant for its effects and risk assessment and a read-across approach from data for both the molybdenum and 2-ethyl hexanoate ions is preferred. The dose additivity approach is used to explain the ecotoxicological effects of 2-ethylhexanoic acid, molybdenum salt based on the data for the individual transformation products (molybdenum and 2-ethylhexanoate ions).

Conclusion on classification

No reliable ecotoxicological data are available for 2-ethylhexanoic acid, molybdenum salt. The substance will dissociate into molybdenum and 2-ethyl hexanoate ions after dissolution in water and hence can be regarded as a mixture of both constituent ions. In the absence of toxicity data for 2-ethylhexanoic acid, molybdenum salt, its classification for environmental hazards is therefore based on the classification of the transformation products (molybdenum and 2-ethylhexanoate ions).

Both molybdenum and 2-ethyl hexanoic acid are not classified as hazardous to the aquatic environment and therefore, it is concluded that 2-ethylhexanoic acid, molybdenum salt is not classified as hazardous to the aquatic environment.