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Environmental fate & pathways

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:
1990
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Comparable to guideline study, GLP
Reason / purpose for cross-reference:
reference to same study
Reason / purpose for cross-reference:
reference to other study
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 301 E (Ready biodegradability: Modified OECD Screening Test)
Deviations:
not specified
Principles of method if other than guideline:
The method was reported to be on the basis of EG-Guideline 79/831 EWG annex V; OECD Guideline 301 E: Modified OECD-Screening
GLP compliance:
yes
Oxygen conditions:
not specified
Inoculum or test system:
activated sludge, industrial, non-adapted
Details on inoculum:
- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): STP for Laboratories, Wupperverband
- Concentration of inoculum: 0.5 mL/900mL.
Duration of test (contact time):
28 d
Initial conc.:
19 mg/L
Based on:
DOC
Parameter followed for biodegradation estimation:
DOC removal
Details on study design:
TEST CONDITIONS
- Test temperature: 22+/-2°C
- Continuous darkness: yes

SAMPLING
- Sampling frequency: DOC-measurements were made on day 0, 7, 14, 21, 27 and 28.

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes

CALCULATION
Percentage DOC-removal = [DOC (start of the test) - DOC (end of the test)/DOC (start of the test)] x 100
Reference substance:
aniline
Parameter:
% degradation (DOC removal)
Value:
6
Sampling time:
28 d
Details on results:
Details were not provided
Results with reference substance:
DOC removal of reference substance (in %): 100 after 28 days.

Time

[h]

DOC

Inoculum blank

DOC

test substance [mg/L]

DOCcorr.*

test substance [mg/L]

DOC removal

 

[%]

o

2

19

17

0

7

2

19

17

0

14

2

18

16

6

21

2

20

18

0

27

2

19

17

0

28

2

18

16

6

DOCcorr.*= value for test substance - value for inoculum

Validity criteria fulfilled:
yes
Remarks:
Reference substance degraded by 100% within 28 days
Interpretation of results:
other: not readily biodegradable
Executive summary:

A 28-d Modified Screening Test was performed on the basis of the OECD guideline 301E with predominantly domestic sewage.

6% degradation was observed within 14 and 28 days.

Trimethylolpropane is not readily biodegradable.

Reference: Müller & Caspers, 1990

Description of key information

Trimethylolpropane was shown not to be readily biodegradable, but fulfilled the criterion for inherent, ultimative biodegradability (70% degradability within 7 days).

Key value for chemical safety assessment

Biodegradation in water:
inherently biodegradable, fulfilling specific criteria
Type of water:
freshwater

Additional information

READY BIODEGRADABILITY

Key study:

A 28-d Modified Screening Test was performed on the basis of the OECD guideline 301E with predominantly domestic sewage. 6% degradation was observed within 14 and 28 days. Trimethylolpropane is not readily biodegradable.

Reference: Müller & Caspers, 1990

Supporting studies:

A 14-d Modified MITI Test (I) was performed on the basis of the OECD guideline 301C with activated sludge. 4% degradation was observed within 14 days on the basis of O2 consumption, 3 % when estimated by test material analysis by HPLC. Trimethylolpropane is not readily biodegradable.

Reference: MITI; <= 1994

The ready biodegradability of trimethylopropane was tested in a 14 -d MITI (I)-Test following a Japanese guideline, which corresponds to OECD 301C. The test substance was investigated at a concentration of 100 mg/L. 30 mg/L of activated sludge was used as inoculum. Degradation of trimethylopropane was recorded over a period of 14 days by analyzing BOD, TOC and the active substance. Trimethylopropane was degraded to 1.7 % (based on BOD) and 3 % (from test material analysis by GC) and is therefore considered not readily biodegradable.

Reference: CITI Japan, 1992

Further studies:

A 20-d Closed Bottle Test was performed with trimethylolpropan at a concentration of 2.4 mg/L.

0% degradation was observed within 5, 10 and 20 days.Trimethylolpropane is not readily biodegradable. As only a short abstract is available, the reliability is not assignable.

Reference: Müller & Caspers, 1973

A 20-d Closed Bottle Test was performed with trimethylolpropan at concentrations of 2.4, 8, 24 and 80 mg/L.

0% degradation was observed within 20 days.Trimethylolpropane is not readily biodegradable. As the used sludge population was adapted and the available information is too scarce, the study is not reliable.

Reference: Anonymous (Bayer), 1973

INHERENT BIODEGRADABILITY

Key study:

The inherent biodegradability of trimethylolpropane was tested in a 28-d- Zahn-Wellens test following the OECD Guideline 302B (draft from 1989) and GLP requirements. With an initial test substance concentration of 100 mg/L and an activated sludge concentration of 0.4 g dry weight/L 100% degradability of trimethylolpropane was determined by DOC-removal. 100% of the reference substance aniline degraded within the test period.

Trimethylolpropane was shown to be 100% inherently biodegradable after 28 days and fulfilled the criterion for inherent, ultimative biodegradability (70% degradability within 7 days).

Reference: Caspers & Müller, 1992

Supporting studies:

The inherent biodegradability was tested in a 17 d Zahn-Wellens-Test following the OECD Guideline 302B. A 0.1% aquatic solution of the test substance was exposed to activated sludge. 95% degradation was measured on day 15 and 98% on day 17 by DOC removal. The substance is inherently biodegradable.

As only a citation of a guideline test is available, the reliabiliy cannot be assigned.

Reference: BASF, Institute Kuhlmann, 1988

FURTHER STUDIES (BOD5, BOD10 and BOD15)

The BOD5 was estimated in the study to be > 5 mg O2/mg trimethylolpropane. For the dossier compilation, a ThOD of 1.908 mg/L was calculated according the formula given in OECD-Guideline 301, Annex IV. From these results, a degradation rate from BOD x 100/ThOD may not be calculated.

As only a short abstract is available, the reliability may not be assigned.

Reference: BASF, Institute Kuhlmann, 1988

The BOD5, BOD10 and BOD15 was estimated in the study to be 0.033, 0.269 and 0.428 mg O2/mg trimethylolpropane.

For the dossier compilation, a ThOD of 1.908 mg/L was calculated according the formula given in OECD-Guideline 301, Annex IV.

From these results, the following degradation rates are calculated: ca. 1.7 % on day 5, ca. 14.1 % on day 10 and ca. 22.4 % on day 15.

As only a short abstract is available, the reliability cannot be assigned.

Reference: Walton & Davis, 1980