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In the assessment of fatty acids, C9 -13 neo, potassium salts, read-across to the assessment entities soluble potassium substances and neodecanoic acid is applied since the ions of fatty acids, C9 -13 neo, potassium salts determine its fate and toxicity in the environment.

 

Potassium

As an essential element for living organisms, potassium has a very low potential for toxicity to freshwater as well as saltwater organisms. Effect concentrations are available for several species but exceed corresponding OECD test limits. In sum, potassium has very low potential for acute aquatic toxicity.

 

Neodecanoic acid

Reliable acute data are available from GLP-conform guideline studies for three trophic levels: algae, invertebrates and fish

- an unbounded value of > 100 mg/L (96h-LL50) was identified for rainbow trout

- an unbounded value of > 457 mg/L (48h-EL50) was identified for the invertebrate species Daphnia magna

- an unbounded value of > 100 mg/L (72h-LL50) was identified for the algae Pseudokirchneriella subcapitata

 

Reliable chronic data are available from GLP-conform guideline studies for two trophic levels: invertebrates and fish

- 21-d NOEC of 4.78 mg/L neoheptanoic acid (structural analogue) for reproduction of D. magna; Chronic Value (ChV) of 1.7 mg/L (QSAR-based estimate) for daphnids

- 14-d NOEC of 2.22 mg/L neodecanoic acid for growth of Oncorrhynchus mykiss; Chronic Value (ChV) of 1.6 mg/L (QSAR-based estimate) for fish

- Regarding algae, an EC10 or NOEC is not available for neodecanoate. However, based on the fact that the EC50 for growth rate of algae is > 100 mg/L, we may assume that it is unlikely that the EC10/NOEC < 1 mg/L. According to the QSAR-based outcome of the model ECOSAR v.2.0, neodecanoic acid has a very low potential for chronic toxicity to green algae since the chronic value (ChV = 10^([log (LOEC x NOEC)]/2)) of 12.3 mg/L is >> 1 mg/L.

 

Regarding the toxicity to aquatic microorganisms, a 4-h NOEC of ≥ 200 mg/L for the inhibition of nitrification by microorganisms (Nitrosomonas sp.) is available.

 

In sum, neodecanoic acid has very low potential for acute aquatic toxicity and a low potential for chronic toxicity.

 

Fatty acids, C9 -13 neo, potassium salts

According to aquatic toxicity data of the dissociation products of fatty acids, C9 -13 neo, potassium salts, the aquatic hazard assessment is based on the most toxic moiety.

 

Regarding acute (short-term) toxicity, the potential is low since relevant EC/LC50 values of potassium ions and neodecanoate are above respective OECD test limits.

 

Regarding chronic (long-term) toxicity, potassium is not expected to have a high potential since potassium as essential macronutrient is added to aquatic test media. Existing aquatic toxicity data of neodecanoic acid and neoheptanoic acid are recalculated for fatty acids, C9 -13 neo, potassium salts based on a maximum neodecanoate content of 84.5 %.

 

- 21-d NOEC of 5.66 mg/L for reproduction of D. magna; Chronic Value (ChV) of 2.01 mg/L (QSAR-based estimate) for daphnids

- 14-d NOEC of 2.63 mg/L for growth of Oncorrhynchus mykiss; Chronic Value (ChV) of 1.89 mg/L (QSAR-based estimate) for fish

Further, a 4-h NOEC > 237 mg/L for the inhibition of nitrification points to a very low potential for toxicity to sewage sludge microorganisms.