Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Henry's Law Constant

The Henry's Law constants of 1,2-Cyclohexanedicarboxylic acid, 4-methyl- (4-MHHPAc), as hydrolysis product of hexahydro-4-methylphthalic anhydride, was considered for the environmental assessment. The value of 2.75E-4 Pa m³/mol shows that 4-MHHPAc is essentially non volatile from surface water.

Distribution modelling

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= 0.236%; Water= 4.89%; Soil= 94.8% and Sediment= 0.028%.

.However, the substance is known to be unstable, rapidly hydrolysing to the corresponding di-carboxylic acid in aqueous media and this process is expected to occur in the environment should release occur. As a result the calculated distribution may not be a reasonable estimate. Similar modelling of the degradation product of the substance, 4 -methyl-1,2 -cyclohexanedicarboxylic acid, estimated distribution in the various environmental compartments as: Air= 0.08%; Water= 20.4%; Soil= 79.4% and Sediment= 0.109%.

Refinement of the modelling, undertaken as part of the CSA, and taking account of the uses of the substance, does not support these estimates.