Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

The OECD SIDS report for 6,6`-tert-butyl-2,2`-methylenedi-p-cresol (SIDS initial assessment profile, UNEP publications, 2000) came to the folloging conclusion which is still valid and amended here by studies which were not available at the time of the SIDS report.

The substance is not readily biodegradable, corresponding to the OECD 301C: 0% after 28 days based on BOD and 1% based on HPLC analysis. A supporting study (OECD Guideline 301 , (Ready Biodegradability: Closed Bottle Test) yielded also 0% biodegradation.

A hydrolysis study is waived due to the very low water solublity which would make that study technically extremely difficult.

The substance, if released to air will react with photochemically produced hydroxy radicals with the half-life of 3.1 hours.

Fugacity level I calculations suggest that the majority of the substance would be distributed into soil if released to soil and/or air compartment, and sediment if released to the aquatic compartment.

When the substance is released to air, significant amount of the substance would be firstly photodegraded, and then any undegraded substance would be deposited to soil where the degradation rate would be very slow. In contrast, when the substance is released to soil directly, it would remain in soil since its solubility is low, it is essentially non-volatile, and the degradtion rate in soil would be low either.

In spite of high hydrophobicity (e.g. .ogPow: 6.25) the substance is not so highly bioconcentrated. A bioconcentration factor BCF of 840 was measured for fish.

Adsorption to particles is high with calculated logKow of 4.7 to 6.3 indicating that the substance is strongly adsorbed to soil and sediment particles.The Henry’s Law Constant calculated on the basis of logPow was found to be 8.02E-07 Pa x m³ x mol-1.