N-(2-ethylhexyl)-8,9,10-trinorborn-5-ene-2,3-dicarboximide

PBT assessment

PBT assessment: overall result

Reference

Name:

N-(2-ethylhexyl)-8,9,10-trinorborn-5-ene-2,3-dicarboximide

Type of composition:

legal entity composition of the substance

State / form:

liquid

Reference substance:

N-(2-ethylhexyl)-8,9,10-trinorborn-5-ene-2,3-dicarboximide

PBT status:

the substance is not PBT / vPvB

Justification:

Persistance

Abiotic Degradation - A photolysis study was conducted with MGK 264. The data generated during this study demonstrate that [14C]-MGK 264 in aqueous solution at pH 7, 25°C, and exposed to light for 30 days does not photolyze. Because of the lack of degradation, the rate constant was determined to be statistically not significantly different from 0, yielding an infinite half-life.

Biotic degradation - An OECD 301B ready bioavailabilty study is available for MGK 264. Mean cumulative CO2 production by mixtures containing MGK 264 was negligible and had achieved, at most, 3% of the theoretical value (ThCO2,110.1 mg CO2) by the end of the test on Day 29. Substances are considered to be readily biodegradable in this test if CO2 production is equal to or greater than 60% of the theoretical value within 10 days of the level achieving 10%. MGK 264 cannot, therefore, be considered to be readily biodegradable.

In addition to the ready bioavailability study, a 365 day aerobic soil metabolism study and a 90 day anaerobic soil metabolism study are available for MGK 264. The average half-lives of MGK 264 was 341 days and 270 days in the aerobic and anaerobic metabolism studies respectively, thus fulfilling the criteria for persistent and also for vP.

The results of these 3 studies show that MGK 264 may be considered to fulfil the criteria for both P and vP based on the lack of biodegradability and the 341 day (worst case) soil DT50 result.

Bioaccumulation

A bioconcentration or bioaccumulation study in aquatic species is not available, however results estimated by QSAR in accordance with Section 1.3 of Annex XI may be used. The QSAR value for MGK 264 using epiwin, BCFBAF v3.01, gives a worst case result of 528. Thus, the criteria for bioaccumulation is not fulfilled.

Toxicity

There is an extensive data set for toxicity of MGK 264 which includes rat and mouse carcinogenicity studies, developmental toxicity studies in rat and rabbit and a reproductive toxicity study in the rat. From the results of these investigations MGK 264 is not classified with respect to carcinogenicity, reproduction or specific organ toxicity and therefore does not fulfil the criteria for T.

Three short term toxicity studies in fish, a short term toxicity study in daphnia and an algal growth inhibition study are available for MGK 264. The lowest 96 -hour LC50 was found in a toxicity study in rainbow trout (under static conditions) and the LC50 was 0.1687 mg/L. Therefore none of the available studies fulfil the criteria of EC50 or LC50 < 0.01 mg/L or <0.1 mg/L and therefore do not meet the criteria of T for aquatic toxicity.