Registration Dossier

Diss Factsheets

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information


Phototransformation in air- Half-life for reaction with photochemically-produced hydroxyl radicals: estimated to be between 0.645 and 0.967 days.

Hydrolysis- A base-catalysed second-order hydrolysis rate constant of 1.248E-002 L/mol-sec was estimated using a structure estimation method. This corresponds to half-lives of 17.602 years at pH 7 and 1.76 years at pH 8.



The screening test inherent to the biodegradability of the substance was calculated using the software BIOWIN v4.10 and theresults indicate that diisobutyl hexahydrophthalate (DIBE) is expected to be readily biodegradable. A number of tests of ready biodegradability have been undertaken with the substance, some of these examining the effects of solubilizing agents, extending the test period beyond 28 days and the use of an adapted inoculum. The results obtained with non-adapted inoculum did not demonstrate ready biodegradability although up to 20% degradation was observed. When an adapted inoculum was used ready biodegradability was demonstrated.



The potential for bioaccumulation of the substance is low - Estimated BCF 22 L/kg ww.


Transport and distribution

Adsorption-desorption-Estimation has been made using high performance liquid chromatography (HPLC) according to OECD test methods. Log Koc soil was estimated to be 3.5 -3.8 and log Koc. sewage sludge was estimated to be 3.7-4.0, corresponding to a KOC.soil of = 3162-6310 and KOC.sewage sludge of 5012-10000 respectively.The adsorption coefficient (Koc) on soil of the substance has also been calculated using the computer program KOCWIN (v2.00). It is predicted that the substance has a Koc of 819 L/Kg.

Henry's Law constant- Estimated using the software HENRYWIN (v3.20). The value of 0.248 Pa m³/mol indicates that the substance is not significantly volatile from surface water.

Distribution modelling– Distribution in environmental compartments has been calculated using a Fugacity model according to Mackay, Level III. Soil and water were found to be the major target compartments.