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Biodegradation in water: screening tests

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Reference
Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
09.04.2018 - 26.09.2018
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)
Version / remarks:
1992
Deviations:
no
GLP compliance:
no
Remarks:
ISO 9001 / ISO 14001 environment
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, non-adapted
Details on inoculum:
The study consisted of six bottles:
2 inoculum blanks (no test item),
2 test bottles (35730),
1 procedure control (sodium acetate) and
1 toxicity control (35730 plus sodium acetate).
Duration of test (contact time):
>= 28 - <= 28 d
Initial conc.:
>= 15 - <= 15 mg/L
Based on:
ThCO2
Remarks:
2.9 mg
Parameter followed for biodegradation estimation:
CO2 evolution
Details on study design:
The study procedures described in this report were in compliance with the OECD guideline
No. 301 B, 1992. In addition, the procedures were designed to meet the test methods of the
ISO standard 10634, 1995.
Key result
Parameter:
% degradation (CO2 evolution)
Value:
>= 59 - <= 61
Sampling time:
28 d
Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable
Executive summary:

The relative biodegradation values calculated from the measurements performed during the test period revealed 61% and 59% biodegradation of 35730, for vessel A and B, respectively (based on ThCO 2 ). Therefore, average biodegradation of the test item after 28 days is 60%. Since the test item consists of a mixture of structurally similar chemicals, the 10-day window need not be applied.

In the toxicity control, more than 25% biodegradation occurred within 14 days (53%, based on ThCO 2 ). Therefore, the test item was assumed not to inhibit microbial activity.

Description of key information

The relative biodegradation values calculated from the measurements performed during the test period revealed 61% and 59% biodegradation of 35730, for vessel A and B, respectively (based on ThCO 2 ).

Key value for chemical safety assessment

Biodegradation in water:
readily biodegradable
Type of water:
other: Milli-RO water

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