Registration Dossier

Environmental fate & pathways

Biodegradation in water: screening tests

Currently viewing:

Administrative data

Link to relevant study record(s)

Reference
Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
26 Apr - 24 May 2011
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: GLP guideline study with acceptable restrictions (no detailed information on composition of inoculum)
Qualifier:
according to
Guideline:
OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))
Deviations:
no
GLP compliance:
yes
Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge (adaptation not specified)
Details on inoculum:
- Source of inoculum/activated sludge: Purchased from Chemicals Evaluation and Research Institute, Japan, on April 14, 2011 (sludge no. 230414)
- Laboratory culture: Cultured under 25 ± 2 °C, not less than 5 mg/L of dissolved oxygen concentration and pH 7.0 ± 1.0
- Concentration of sludge: 4647 mg/L (25 Apr 2011)
Duration of test (contact time):
28 d
Initial conc.:
100 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
TEST CONDITIONS
- Composition of medium: recommended medium in the guideline
- Test temperature: 25.0 °C
- Suspended solids concentration: 30 mg/L
- pH at the end of exposure: in the samples sludge + test substance: 7.18 – 7.39, in the sample water + test substance: 8.86

TEST SYSTEM
- Culturing apparatus: Coulometer Type OM-2001A, Ohkura Electric Co., Ltd.
- Number of culture flasks/concentration: 3 (sludge + test sub.)
- Measuring equipment: Coulometer

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes, 1 replicate
- Abiotic sterile control: no
- Toxicity control: no
- Reference substance: yes, 1 replicate
Reference substance:
aniline
Remarks:
100 mg/L
Parameter:
% degradation (O2 consumption)
Value:
2
Sampling time:
28 d
Remarks on result:
other: Mean of three replicates
Results with reference substance:
Degradation of aniline: 67% and 74% degradation after 7 days and 14 days, respectively; 60% pass level was reached.

Table 1: Residual rate and degradation rate

Results of

Test solution

Residual rate (%)

Degradation rate (%)

BOD

Sludge + test substance

-

2 *

Determination of 1,4-isomer (GC)

Sludge + test substance

99 *

6 *

Water + test substance

105

-

Determination of 1,5-isomer (GC)

Sludge + test substance

100 *

0 *

Water + test substance

100

-

* mean values

 

Table 2: Residual amount of TOC

Test solution

Residual amount of TOC (1)

Residual rate (%)

Degradation rate (%)

Sludge + test substance

18.9 *

106 *

2 *

Water + test substance

19.2

108

-

* mean values

(1) Calculation by subtracting control blank from sludge + test substance, and water blank from water + test substance, respectively

 

Validity criteria fulfilled:
yes
Interpretation of results:
under test conditions no biodegradation observed

Description of key information

Under test conditions no biodegradation observed: 2% after 28 d based on O2 consumption (OECD 301C)

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed

Additional information

One study is available investigating the ready biodegradability of the test substance. The study was performed according to OECD 301C under GLP conditions using a mixed population of activated sewage sludge microorganisms (Tosoh Corporation, 2011). A biodegradation of 2% based on O2 consumption was attained after 28 d indicating that the substance is not readily biodegradable under the test conditions. The toxicity control attained 67% degradation after 7 d and 74% after 28 d indicating that the test substance is not inhibitory to the inoculum. In conclusion the test substance is not readily biodegradable according to the OECD criteria.