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PBT assessment

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PBT assessment: overall result

Oxydiethylene dibenzoate
Type of composition:
legal entity composition of the substance
State / form:
Reference substance:
Composition 1
PBT status:
the substance is not PBT / vPvB

PBT/vPvB criteria and justification

Persistence (P) Assessment:

A substance is not considered to be persistent if it can be demonstrated that it has potential to degrade (via photolysis, hydrolysis and/or biodegradation).

In a modified Sturm test DEGDB was found to have degraded by 17% after 2 days, 71% after 10 days, and by 93% at the end of the 28 -day biotic phase of the test (HLS 1998, VCL246/972257). The positive control substance, sodium benzoate, which was analysed contemporaneously degraded rapidly (65% degradation after 6 days), and confirmed that the inoculum was viable and that the test was valid.

Substances are considered to be readily degradable in this test if CO2 production is equal to or greater than 60% of the theoretical value within ten days of the level achieving 10%. In the Modified Sturm test, DEGDB met these criteria, so may be considered to be readily biodegradable.

Therefore, DEGDB does not meet the Persistent (P) or very Persistent (vP) criteria.

Bioaccumulation (B) Assessment:

According to the adaptations found in column 2 of annex IX, the bioconcentration in aquatic species study can be waived if direct and indirect exposure to the aquatic environment is unlikely. This substance has no defined uses where direct application to the aquatic environment would occur, and because the substance is readily biodegradable, wastewater treatment would also make indirect exposure to the aquatic environment unlikely. In addition, evidence of a low bioaccumulation potential is provided by QSAR estimates showing BCF values < 100 L/kg using a regression method based upon the experimental log Kow value of 3.2, and using the Arnot-Gobas QSAR method the BCF/BAF values for all trophic levels are < 10 L/kg when biotransformation rates are utilized and ~ 200 L/kg when biotransformation is not included in the estimation. For these reasons, and for animal welfare reasons, it is believed that a bioconcentration study is not justified and is not proposed.

Therefore, DEGDB does not meet the Bioaccumulative (B) or very Bioaccumulative (vB) criteria.

Toxicity (T) Assessment:

DEGDB was not identified as P/vP or B/vB therefore no further assessment is needed.

Conclusion of PBT/vPvB assessment

This available data showed that DEGDB is not classified as P/vP. Further bioaccumulation testing is not justified. There is a lack of potential exposure to the aquatic environment (based on adaptations found in column 2 of annex IX) and modelled Log Pow data would indicate that the potential for bioaccumulation would be low. Analysis of the T criteria is not required based on the fact that the substance is not P/vP or B/vB, therefore, DEGDB is not classified as PBT or vP or vB.