Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Stability

Stability of the substance in the atmosphere was calculated using the computer program AOP program (v 1.92). It is predicted that the substance will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals. The half-life for this reaction in air is estimated to be approximately 111 hours.

A base-catalysed second-order hydrolysis rate constant (Kb) of 0.0564 L/(mol-sec) at 25 deg C was estimated using a structure estimation method.

This corresponds to half-lives of 3.90 years at pH 7 and 142.3 days at pH 8.

Biodegradation

Ready biodegradability has been investigated in a shake flask test conducted according to EPA test methods. Diethyl phthalate was found to be readily biodegradable.

In accordance with REACH Regulation 1907/2006, Annex IX, Column 2, simulation tests of biodegradation in water, sediment and soil do not need to be conducted as the substance is readily biodegradable. Values have been calculated using a Fugacity model according to Mackay, Level III usingEPIWIN (v.4.11) - Half life in water: 360 hours; Half life in sediment: 3240 hours; Half life in soil: 720 hours.

Bioaccumulation

In accordance with REACH Regulation 1907/2006, Annex IX (9.3.2), Column 2, a study of bioaccumulation need not be conducted if the substance has a low potential for bioaccumulation (based on a log Pow <3. Diethyl phthalate has a log Pow of 2.2 and waiving of the data requirement is justified on the basis of the stated criterion.

BCF has been calculated using the computer program BCFBAF (v3.01). It is predicted that the substance has BCF of 13.1 L/kg wet weight, indicating a low potential for bioaccumulation and supporting the justification for waiving of the test requirement.

Transport and distribution

The adsorption coefficient (Koc) on soil and on sewage sludge using high performance liquid chromatography (HPLC) has been estimated and adsorption coefficients estimated to be log Koc,soil = 2.34 and log Koc, sewage sludge = 2.39.

These values correspond to a Koc,soil = 217 and Koc,sewage sludge = 245.

The McCall classification scheme classifies the substance as having medium mobility in soil (Koc 150 - 500).

The Henry's Law constant was estimated using the software HENRYWIN (v3.20). The value of 0.0256 Pa m³/mol indicates that the substance is essentially not volatile from surface water.

Distribution in environmental compartments has been calculated using a Fugacity model according to Mackay, Level III. Distribution in various environmental compartments is estimated as: Air= 1.95%; Water= 22.1%; Soil= 75.7% and Sediment= 0.224%.

Soil and water were then found to be the major target compartments.