Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

Only one study was available and was selected as key study.

In this study (RCC, 2006), the test item Paradimethoxybenzene was investigated for its ready biodegradability in a manometric respirometry test over 28 days according to EU Commission Directive 92/69 EEC, C.4-D (1992) and OECD Guideline for Testing of Chemicals No. 301 F (1992).

The percent biodegradation of the test item was calculated based on the theoretical oxygen demand (ThOD) of 2.20 mg O2/mg test item.

The biochemical oxygen demand (BOD) of Paradimethoxybenzene in the test media significantly increased from about Exposure Day 18 until test termination after 28 days. At the end of the 28-day exposure period, the mean biodegradation of Paradimethoxybenzene amounted to 81%. Consequently, Paradimethoxybenzene was found to be biodegradable under the test conditions within 28 days. Moreover, the pass level for ready biodegradability, i.e. biodegradation of at least 60% of the ThOD in a 10-day window within the 28-day period of the test, was reached.

Consequently, Paradimethoxybenzene was found to be readily biodegradable under the test conditions within28 days.

Other primary biodegradation data was available from soil studies, indicating that 100% of Paradimethoxybenzene (at 15 mg/l)

was biodegraded by a mixed soil microflora within 8 days, based on loss of UV absorbancy (Alexander & Lustigman, 1966).