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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

2 studies  available (2002 and 2009)showing a readily biodegradation between 75.6% and 88% after 28 days.
1 study available (2012) showing a inherent biodegradation at 65% after 28 days

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable

Additional information

Ready biodegradation

A study was performed to assess the ready biodegradability of the test item in an aerobic aqueous medium (Dr U.NOACK Laboratorium, 2002). The method was designed to be compatible with the OECD Guidelines for Testing of Chemicals (1992) No 301B, "CO2 evolution Test”

 

The test item, at a concentration of 12.4 mg C/L, was exposed to sewage treatment micro-organisms with mineral medium in open culture vessels (aerated) in the dark at ambiant temperatures for 28 days.

The degradation of the test item was assessed by the determination of the CO2 evolution. Control solutions with inoculum and the reference item, (sodium acetate trihydrate), together with a toxicity control were used for validation purposes.

The test item attained 88% degradation after 28 days and is considered to be readily biodegradable under the strict terms and conditions of OECD Guideline No 301B.

 

 

A study was performed to assess the ready biodegradability of the test item in an aerobic aqueous medium (AQUATOX 2009). The method was designed to be compatible with the OECD Guidelines for Testing of Chemicals (1992) No 301B, "CO2 evolution Test”

 

The test item, at a concentration of 12.7 mg TOC/L, was exposed to sewage treatment micro-organisms with mineral medium in open culture vessels (aerated) in the dark at ambiant temperatures for 28 days.

The degradation of the test item was assessed by the determination of the CO2 evolution. Control solutions with inoculum and the reference item, (sodium acetate trihydrate), together with a toxicity control were used for validation purposes.

The test item attained 75.6% degradation after 28 days and is considered to be readily biodegradable under the strict terms and conditions of OECD Guideline No 301B.

 

 

Inherent biodegradation

In a study (2012), the inherent biodegradability of Octylphosphonic Acid (OPA) (initial concentration: 202.1 mg/L), was tested in a Zahn-Wellens test during 28 days, according to OECD guideline for Testing of Chemicals n°302B (1992).

Inoculum used in the study was 300 mg/L of a sludge from a sewage treatment plant, (predominantly domestic sewage).

The percentage of biodegradation was estimated by following the DOC removal.

-OPA did not adsorb on activated sludge.

-OPA was not inhibitory to activated sludge at the tested concentration of 202.1 mg/L because degradation was > 35% within 14 days.

The corresponding percentage of biodegradation obtained was 65% of DOC removal after 28 days.

Under the test conditions, OPA is considered as inherent primary biodegradable.