Registration Dossier

Diss Factsheets

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Adsorption / desorption

The adsorption coefficients on soil of the registered substance (Koc,n: METH) and the corresponding acid (Koc,i: METHAc) were calculated according to the EPA model KOCWIN (v2.00).

It was verified, using the Log Kow method, that Koc,i < Koc,n.

According to the McCall classification scheme, both the anhydride and acid forms are very highly mobile (0 < Koc < 50) on soil.

The higher value of the anhydride form, Koc= 25.5 L/Kg, was selected with conservative approach for the environmental assessment.

Henry's Law constant

The Henry's Law constants were estimated using the software HENRYWIN (v3.20).

The HLCs of methylbicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid (METHAc) in its identified isomeric forms, as hydrolysis products of 1,2,3,6-tetrahydromethyl-3,6-methanophthalic anhydride, were considered for the environmental assessment.

The value of 5.6E-07 Pa m³/mol, as a mean of estimated values, indicates that METHAc is essentially non volatile from surface water.

Distribution modelling

Distribution in environmental compartments has been calculated using a Fugacity model, under the emission scenario of 1000 kg/h into each of air, water and soil compartments, according to Mackay, Level III.

The distribution of 5-methylbicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid (5-METHAc) was estimated as: Air= 0.0%; Water= 34.6%; Soil= 65.4% and Sediment= 0.06%.

The distribution of 1-methylbicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid (4-METHAc) was estimated as: Air= 0.0%; Water= 34.5%; Soil= 65.5% and Sediment= 0.06%.

The soil, and less water, were then found to be the major target compartments.