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Environmental fate & pathways

Biodegradation in water: screening tests

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Description of key information

The test substance attained betweeen 10 and 15% degradation after 28 days and cannot therefore be considered as readily biodegradable as defined within strict OECD Guidelines.

Key value for chemical safety assessment

Biodegradation in water:
inherently biodegradable, not fulfilling specific criteria

Additional information

Method: Closed bottle test according to OECD Guideline No. 301D and EEC Directive 67/548 Annex V C6. as published in 84/449/EEC.

Duration: 28 days

Temperature: 21± 1ºC

Results:

Test concentration: 2 mg/l

Oxygen depletion (28 days): 0.375 mgO2/l

Theoretical oxygen demand (ThOD): 3.74 mg/O2/l

Percentage biodegradation (28 days): 10 -15%

Sodium benzoate (the standard reference substance) attained 92% degradation within 28 days.

Oxygen depletions in the inoculated and non-inoculated controls were within prescribed limits.

Method 2. Assessment of Ready Biodegradability, CO2 Evolution test OECD 301B- referenced as Method C.4 -C of Commission Regualtion (EC) no. 440/2008

Duration: 60 days

Temperature 20± 2ºC

Results:

Test concentration : 10mg/Carbon/L ( equivalent to 34.8 mg test item/L)

Biodegredation 15% after 28 days and 26% after 60 days

HPLC analysis, 65-67% of AS100 was recovered after 60 days. Recovery of hydrolysis product at 60days ranged between 7.44 and 7.83mg/L

Sodium Benzoate attained 87% biodegradation after 14 days, 88% after 28 days and 89% after 60 days therby confirming the suitability of the inoculum and test conditions

Validity of test:

1. Total Co2 evolution in the inoculum control vessel on Day 28 was 28.18mg/L - validation criteria satisfied

2. Inorganic Carbon (IC) content of the test item suspension in mineral medium at the start of the test was below 5% of the Total Carbon (TC) content

3. The difference between the values for CO2 production at the end of the test for the replicate vessels was <20% and hence satisfied the validation criterion given in the OECD test guidelines

Conclusion:

The test substance attained betweeen 10 and 15% degradation after 28 days and cannot therefore be considered as readily biodegradable as defined within strict OECD Guidelines.