Neodecanoic acid, zirconium salt

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

0.14 mg/L

Assessment factor:

10

Extrapolation method:

assessment factor

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

0.014 mg/L

Assessment factor:

100

Extrapolation method:

assessment factor

STP

Hazard assessment conclusion:

no hazard identified

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

0.77 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

0.077 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Hazard for air

Air

Hazard assessment conclusion:

no hazard identified

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

PNEC soil

PNEC value:

0.075 mg/kg soil dw

Extrapolation method:

equilibrium partitioning method

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

PNEC oral

PNEC value:

0.021 g/kg food

Assessment factor:

90

Additional information

Metal carboxylates are substances consisting of a metal cation and a carboxylic acid anion. Dissociation of dissolved neodecanoic acid, zirconium salts resulting in zirconium cations and neodecanoate anions may be assumed under environmental conditions. The respective dissociation is reversible, and the ratio of the salt /dissociated ions is dependent on the metal-ligand dissociation constant of the salt, the composition of the solution and its pH.

Based on analysis of thermodynamic stability of aqueous zirconium species, the concentration of free Zr4+ ions under environmental conditions is barely detectable. Ionic zirconium (Zr4+) at relevant pH conditions (pH 7 - 8) of aquatic and terrestrial environments will rapidly transform to zirconium-oxide and -hydroxide complexes, precipitate and not be bioavailable to aquatic organisms. Therefore, zirconium has a very low mobility and bioavailability under most environmental conditions whereas neodecanoate is rather mobile.

Thus, it may reasonably be assumed that the respective behaviour of zirconium cations and neodecanoate anions in the environment determine the fate of neodecanoic acid, zirconium salts upon dissolution with regard to (bio)degradation, bioaccumulation, partitioning resulting in a different relative distribution in environmental compartments (water, air, sediment and soil) and subsequently its ecotoxicological potential.

Thus, in the assessment of environmental fate and pathways of neodecanoic acid, zirconium salts, read-across to the assessment entities zirconium ions and neodecanoate is applied since the individual ions of neodecanoic acid, zirconium salts determine its environmental fate and toxicity. Since zirconium ions and neodecanoate ions behave differently in the environment, regarding their fate and toxicity, a separate assessment of each assessment entity is performed. Please refer to the data as submitted for each individual assessment entity. For a documentation and justification of that approach, please refer to the separate document attached to section 13, namely Read Across Assessment Report for neodecanoic acid, zirconium salts.

Conclusion on classification

Aquatic toxicity studies of neodecanoic acid, zirconium salt are not available. Read-across to the assessment entities zirconium substances and neodecanoic acid is applied since the ions of neodecanoic acid, zirconium salt determine its fate and toxicity in the environment. Zirconium is poorly soluble and precipitates under most environmental conditions whereas neodecanoate is rather mobile.

 

Acute toxicity data:

EC/LC50 values of zirconium and of neodecanoate are above the OECD test limit of 100 mg/L for short-.term toxicity tests. Thus, the potential for acute toxicity of neodecanoic acid, zirconium salts is expected to be low. Therefore, neodecanoic acid, zirconium salt does not meet classification criteria as short-term hazard to the aquatic environment under Regulation (EC) No 1272/2008.

 

Long-term toxicity:

The potential of chronic toxicity of neodecanoic acid, zirconium salts is expected to be low based on the following:

- no acute toxicity to algae, crustacea and fish up to the OECD test limit of 100 mg/L for short-term toxicity tests for zirconium cations and neodecanoate anions

- Zirconium is poorly soluble and precipitates under most environmental conditions rendering zirconium biologically unavailable

- available chronic EC for zirconium, i.e. the 72h- NOErL (growth rate of algae) = 32 mg/L, is above the OECD test limit of 10 mg/L for chronic toxicity tests

- available chronic (equivalent) EC for neodecanoate for three trophic levels are at least above 1 mg/L.

- Criteria of Category Chronic 4 (safety net) are also not met

Thus, the potential for long-term toxicity of neodecanoic acid, zirconium salts is expected to be low. Therefore, neodecanoic acid, zirconium salt does not meet classification criteria as long-term hazard to the aquatic environment under Regulation (EC) No 1272/2008.

 

In sum, based on read-across of toxicity data available for zirconium and neodecanoate, neodecanoic acid, zirconium salt does not meet aquatic hazard criteria of Regulation (EC) No 1272/2008 and its subsequent adaptation.