Reaction mass of 2-ethylhexyl (3-isocyanato-4-methylphenyl)carbamate and 2-ethylhexyl (5-isocyanato-2-methylphenyl)carbamate and 2-ethylhexyl (3-isocyanato-2-methylphenyl)carbamate

PBT assessment

PBT assessment: overall result

Reference

Name:

Reaction mass of 2-ethylhexyl (3-isocyanato-4-methylphenyl)carbamate and 2-ethylhexyl (5-isocyanato-2-methylphenyl)carbamate and 2-ethylhexyl (3-isocyanato-2-methylphenyl)carbamate

Type of composition:

legal entity composition of the substance

State / form:

liquid

Reference substance:

Reaction mass of 2-ethylhexyl (3-isocyanato-4-methylphenyl)carbamate and 2-ethylhexyl (5-isocyanato-2-methylphenyl)carbamate and 2-ethylhexyl (3-isocyanato-2-methylphenyl)carbamate

Reference substance:

Reaction mass of 2-ethylhexyl (3-isocyanato-4-methylphenyl)carbamate and 2-ethylhexyl (5-isocyanato-2-methylphenyl)carbamate and 2-ethylhexyl (3-isocyanato-2-methylphenyl)carbamate

Reference substance:

Reaction mass of 2-ethylhexyl (3-isocyanato-4-methylphenyl)carbamate and 2-ethylhexyl (5-isocyanato-2-methylphenyl)carbamate and 2-ethylhexyl (3-isocyanato-2-methylphenyl)carbamate

PBT status:

the substance is not PBT / vPvB

Justification:

PBT assessment

Assessment of PBT/vPvB Properties has been conducted in accordance with the guidance given in Annex XIII of Regulation 1907/2006 (as amended by Commission Regulation No 253-2011 of 15 March 2011). A summary of these findings is as presented below:

 

Persistence

A key study is available on ready biodegradability of the substance which was conducted in accordance with OECD test guidelines 301B and EU-method C.4.C. The result of the study showed that the overall degradation over 28 days was 12% (CO2 evolution), and thus was concluded that the substance it Not Readily Biodegradable and as such meets the criterion for Persistent/very Persistent.

 

Bioaccumulation

The hydrophobic substance is highly insoluble (0.13237 mg/L (QSAR)) reaction mass with a molecular weight of 304.383.The substance is highly unstable in water, due to the reactivity of the isocyanate functionality to aqueous media (observations have shown that hydrolysis occurs in <15mins) forming amine which reacts with another isocyanate group to yield urea.

A key study is available assessing the substances n-Octanol/Water Partition Coefficients in accordance with OECD guideline 117 and EU-Method A.8. The study concluded that the test substance, based on 5 peak assignments from HPLC-UV analysis the corresponding log Kow values were as follows: 3.6, 3.8, 3.9, >6.5, and >6.5 (QSAR Log Kow: 6.26). According to Table C.4-1: Screening information for Persistence, Bioaccumulation, and Toxicity from Part C: PBT/vPvB assessment (2017), the substance is between the criteria for being not bioaccumulate and potentially bioaccumulative (not b or vB:Log Kow ≤ 4.5 / potentially b or vB: Log Kow > 4.5) in aquatic organisms.

The linear relationship between bioaccumulation and log kow > 6 the log BCF does not increase linearly with log Kow and as such it cannot be concluded as bioaccumulative on the basis of the octanol-water partition coefficient alone.

Due to the medium to high adsorption potential (log Koc 3.38 to > 5.63) it is expected that the substance or its metabolites will bind to sewage sludge and be removed from the water phase. In total, the concentrations in the environmental water phase are expected to be very low and not relevant for bioaccumulation.

From the aquatic toxicity studies using raphidocelis subcapitata, microorganisms from domestic sludge, daphnia magna and Pimephales promelas, there was no evidence of uptake in the organisms given the lack of effects above the limit of solubility under the conditions of the studies which were conducted to OECD test guidelines 201, 209, 203 and 202.

In conclusion, based on the information above it is proposed that the substance is or is not bioaccumulative/very bioaccumulative. The substance is extremely unstable in water, and does not exist for sufficient time to become bioaccumulated within aquatic organisms. Furthermore available measurements of log Kow indicate that the substance is likely to be outside of the ranges indicative of bioaccumulation should it be available for exposure. On this basis, bioaccumulation is not proposed. 

Toxicity

The substance is classified as chronic aquatic toxicity category 4 based on the substance not being biodegradable, insoluble and having a log Kow >4. The substance however was not seen to be toxic above the limit of solubility to which the results are provided below:

Pimephales promelas 96-hour LC50 > 0.50 mg formulation/L

Raphidocelis subcapitata 72-hour >1.0 mg/L

Activated sludge microorganisms 3-hour EC50 1000 mg/L

Daphnia magna 48-hour EC50 > 0.50 mg formulation/L

 

The substance is classified for reproductive toxicity (category 2) according to Regulation (EC) 1272/2008 based on effects noted in a key OECD Guideline 422 study, therefore based on this the substance meets the criterion for T.

 

Overall conclusions

The biodegradation study determined that the substance is not readily biodegradable.

The substance is or is not bioaccumulative/very bioaccumulative. The substance is extremely unstable in water, and does not exist for sufficient time to become bioaccumulated within aquatic organisms. Furthermore available measurements of log Kow indicate that the substance is likely to be outside of the ranges indicative of bioaccumulation should it be available for exposure. On this basis, bioaccumulation is not proposed. 

The substance is also classified as a suspected reproductive toxicant, therefore meeting the criterion for being toxic.

Based on the information above PBT / vPvB criteria are not fulfilled on the basis of the bioaccumulation potential