4-hydroxybutyl acrylate

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: inherent biodegradability

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study without detailed documentation

Qualifier:

according to guideline

Guideline:

OECD Guideline 302 B (Inherent biodegradability: Zahn-Wellens/EMPA Test)

Qualifier:

according to guideline

Guideline:

other: ISO 9888

GLP compliance:

not specified

Specific details on test material used for the study:

- Test substance: Butanediolmonoacrylate
- Chemical name: 2-Propenoic acid, 4-hydroxy ester

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, industrial (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge: activated sludge from an industrial waste water treatment plant (BASF AG).
- Concentration of sludge: 1 g/L dry matter.

Duration of test (contact time):

8 d

Initial conc.:

737 mg/L

Based on:

test mat.

Initial conc.:

400 mg/L

Based on:

DOC

Parameter followed for biodegradation estimation:

DOC removal

Parameter:

% degradation (DOC removal)

Value:

90 - 100

Sampling time:

8 d

Details on results:

DOC removal (%):
- 0 % after 0 day
- 2 % after 0.125 day
- 7 % after 1 day
- 63 % after 4 days
- 79 % after 6 days
- 92 % after 8 days
Degradation products: not measured

Validity criteria fulfilled:

not specified

Interpretation of results:

inherently biodegradable

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

9 Dec 2004 to 31 Dec 2004

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 A (Ready Biodegradability: DOC Die Away Test)

Version / remarks:

1993

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.4-A (Determination of the "Ready" Biodegradability - Dissolved Organic Carbon (DOC) Die-Away Test)

Version / remarks:

Official Journal of the European Communities L383 A, 35th year, 29 December 1992

Deviations:

no

Qualifier:

according to guideline

Guideline:

ISO 7827 (Evaluation in an Aqueous Medium of the "Ultimate" Aerobic Biodegradability of Organic Compounds - Method by Analysis of Dissolved Organic Carbon (DOC))

Version / remarks:

1994

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Specific details on test material used for the study:

- Test substance: Butanediolmonoacrylate
- Chemical name: 2-propenoic acid, 4-hydroxybutylester
- Batch number: 010078 EDA 0
- Aggregate state: liquid
- Date of production: 10 July 2004
- Purity of the test substance: 99.3 corrected peak area-%
- Impurities: water 0.04 g/100g
- Stability: guaranteed by sponsor
- Expiry date: January 10, 2005

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: Activated sludge from a laboratory wastewater plant treating municipal sewage was used. The concentration of activated sludge in the test assay was 30 mg/L (dry substance). The inoculum was pre-aerated for about 24 hours before the start of the test. 

Duration of test (contact time):

21 d

Initial conc.:

32.3 mg/L

Based on:

test mat.

Initial conc.:

20 mg/L

Based on:

DOC

Parameter followed for biodegradation estimation:

DOC removal

Details on study design:

TEST CONDITIONS
- Test temperature: 22 ± 2 °C
- pH: 7.4 - 7.8
- pH adjusted: yes
- Analytical method: DOC elimination

CONTROLS
- Inhibition control (with reference and test substance, with inoculum)
- Physico-chemical (abiotic) elimination control (with test substance, without inoculum)
- Adsorption control (with test substance, with inoculum*) 
 * Bacterial activity was stopped by addition of mercury chloride solution.

Reference substance:

aniline

Test performance:

VALIDITY CRITERIA
- Deviation of the degradation degree of the test substance in the plateau phase was 20 %.
- Degradation degree of the reference substance was >70 % after 14 days (see 'Results with reference substance')
- Degradation degree in the inhibition control was >35 % after 14 days.

Key result

Parameter:

% degradation (DOC removal)

Value:

>= 90 - <= 100

Sampling time:

21 d

Details on results:

The adaption phase was 2 days. The degree of biodegradation increased from 24% at day 3 in a dose-dependent manner to approximately 100% after 14 days, see 'Any other information on results incl. tables'. The test was terminated after 21 days, as the test substance was completely mineralized (the duration of the degradation phase was approximately 12 days). The 10-day window was met.

CONTROLS
- Inhibition control: The inhibition control was degraded for 90 - 100% after 14 days
- Physico-chemical (abiotic) elimination of the test substance (% DOC) was < 10 at the end of the test
- Elimination of the test substance by adsorption (% DOC) was < 10 after 5 days
- Kinetic control (DOC degree in %): 0 % after 1 day and 96 % after 3 days

Results with reference substance:

Reference substance (aniline): 90 - 100 % degradation after 14 days.

Table: DOC-degree (%)

Day	RS	IH	TS mv
0	0	0	0
1	-4	1	4
3	96	12	24
5	98	80	59
7	95	88	76
10	92	95	95
14	99	97	100
17	99	98	98
20	98	98	98
21	98	98	99

RS: Reference substance

IH: Inhibition control

TS mv: Test substance, mean value

Validity criteria fulfilled:

yes

Remarks:

see 'Test performance'

Interpretation of results:

readily biodegradable

Description of key information

The substance is readily biodegradable as observed in a screening study according to OECD TG 301A.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Additional information

Two screening studies on the biodegradability of the test substance are availabe: one ready test and one inherent test.

The ready test was selected as key study, as this study was performed most recent, was GLP-compliant and performed according to OECD guidelines. The biodegradation potential of the substance in water in a screening study according to OECD TG 301A (DOC Die Away Test) and in compliance with GLP criteria (BASF, 2004). In this study 20 mg/L test substance (expressed as DOC) was inoculated with non-adapted activated sludge from a domestic sewage treatment plant for 21 days under aerobic conditions. The adaption phase was 2 days. The degree of biodegradation increased from 24% at day 3 in a dose-dependent manner to approximately 100% after 14 days. Therefore the test was aborted early, after 21 days (the duration of the degradation phase was approximately 12 days). The 10-day window criterion was met. The inhibition control was degraded for 90 - 100% after 14 days. Based on these results, the substance was assessed to be readily biodegradable.

The study selected as supporting study, determined the inherent biodegradability of the test substance according to OECD 302B (BASF, 1978). No detailed documentation is available. In this study, 737 mg/L of test substance (corresponding to 400 mg/L DOC) was inoculated with activated sludge from an industrial waste water treatment plant. The degree of biodegradation (based on DOC-removal) was 7% after 1 day, 63% after 4 days and increased to 79% and 92% after 6 and 8 days, respectively. Based on these results, the substance was assessed to be inherently biodegradable.