Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Stability

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 6.4 hours.

The substance is highly unstable at pH 4, 7 and 9 and 20, 30 and 50°C, respectively, hydrolysing to the diacid. Instability increased as temperature and pH increased. The half life is in the order of minutes.

 

 

Biodegradation

Ready biodegradability has been investigated in a DOC-die away test according to EU test methods. Tetrahydrophthalic anhydride was found to be readily biodegradable but failed to meet the 10-day window criterion for the test.

Level III fugacity modelling indicates degradation in water, sediment and soil with half lifes estimated as 360, 3240 and 720 hours respectively

 

Bioaccumulation

BCF has been calculated using the computer program BCFBAF (v3.00). It is predicted that the substance has BCF of 3.297 L/kg wet weight. This is in agreement with the experimentally determined BCF of 4-cyclohexene-1,2-dicarboxylic acid (CAS No. 88-98-2), the degradation product of the submission substance, determined according to OECD test methods, which was as follows: < 0.2 at a test concentration of 2 mg/L and < 2 at a test concentration of 0.2 mg/L.

 

Transport and distribution

The adsorption coefficient (Koc) on soil and on sewage sludge using high performance liquid chromatography (HPLC) was estimated according to OECD test methods. Log Koc soil was estimated to be 1.70 and log Koc.sewage sludge was estimated to be 1.72. For the degradation product formed by hydrolysis Log Koc soil was estimated to be -1.34 and log Koc sewage sludge was estimated to be -1.57. The substance and its degradation product are both regarded as being highly mobile in soil.

The Henry's Law constant of 1.92 Pa-m3/mole indicates that the substance may not be significantly 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 - 0.0363%; Water - 32.8%; Soil - 67.1% and Sediment - 0.0738%. Refining modelling to examine distribution following emissions to waste water results in the following distribution: Air - 0.0319%; Water - 99.6%; Soil - 0.284% and Sediment - 0.0482%