Registration Dossier

Ecotoxicological information

Endpoint summary

Administrative data

Description of key information

Additional information

No experimental data evaluating the toxicity to terrestrial organisms is available for 3,5,5-trimethylhexyl 3,5,5 trimethylhexanoate  (CAS 59219-71-5). The substance is not toxic to aquatic organisms up to the limit of water solubility and in addition, available data indicate that 3,5,5-trimethylhexyl 3,5,5-trimethylhexanoate is not bioaccumulative. Based on the available information, toxicity to terrestrial organisms is not expected to be of concern.

Intrinsic properties, fate and bioaccumulation

Due to its low vapor pressure ( 0.0193 Pa at 20°C ), indirect exposure to soil via the air through deposition is unlikely. Indirect exposure to soil through land spreading of activated sludge is also unlikely since this substance is readily biodegradable and it is not considered as highly adsorbable (log Koc < 5). According to the Guidance R.7.c (June 2017), in the case of readily biodegradable substances which are not directly applied to soil, it is generally assumed that the substance will not enter the terrestrial environment. Therefore the terrestrial exposure is unlikely.

Moreover the quick metabolism of aliphatic esters and their enzymatic hydrolysis products demonstrated in the literature in numerous organisms, as well as the estimated BCF/BAF values with the Arnot-Gobas model (BCF and BAF values were calculated to be 152.9/703.9 L/kg, respectively), both indicate that 3,5,5-trimethylhexyl 3,5,5 trimethylhexanoate will not be bioaccumulative.

Considering this, one can assume that the chronic exposure of 3,5,5-trimethylhexyl 3,5,5-trimethylhexanoate to the soil organisms is considered as unlikely.

Aquatic ecotoxicity data

Aquatic toxicity tests of the substance to fish, invertebrates and microorganisms showed no adverse effects in the range of the water solubility (1.5-4.4 µg/L at 20 °C). The obtained results indicate that the test substance is likely to show no toxicity to soil organisms as well.

Conclusion

According to the Guidance R.7.c (June 2017), in the case of readily biodegradable substances which are not directly applied to soil, it is generally assumed that the substance will not enter to the terrestrial environment. Taking int account the intrinsic properties of 3,5,5 -trimethylhexyl 3,5,5 trimethylhexanoate (low vapor pressure and log Koc < 5) and its ready biodegradability, the indirect exposure of the soil compartment is unlikely. In addition since the substance is not bioaccumulable, it will not reach levels of concern into the organisms. So chronic exposure of terrestrial organisms can be considered of no concern.

Furthermore no toxicity to terrestrial organisms is expected since no chronic adverse effects to aquatic organisms was observed up to the solubility limit of the substance (Guide R.7c, June 2017).

Based on the available information, toxicity to soil organisms is not expected to be of concern and additional tests are not judged necessary.  

A detailed reference list is provided in the technical dossier (see IUCLID, section 13) and within the CSR.