Ethylene bis(3-mercaptopropionate)

Biodegradation in water: screening tests

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:

2012

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:

July 1992

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge: Liede STP of Guangzhou
- Preparation of inoculum for exposure: coarse particles were removed; sludge was washed with mineral medium, after sedimentation, sludge was resuspended in mineral medium
- Pretreatment: none
- Concentration of sludge: 4.0 g dry solid/L

Duration of test (contact time):

28 d

Initial conc.:

31 mg/L

Based on:

test mat.

Initial conc.:

12.3 mg/L

Based on:

TOC

Parameter followed for biodegradation estimation:

CO2 evolution

Details on study design:

TEST CONDITIONS
- Composition of medium: potassium phosphate buffer solution with Ca, Mg, and Fe added
- Test temperature: 22+-2 °C
- Suspended solids concentration: 30 mg/L

TEST SYSTEM
- Number of culture flasks/concentration: 2

SAMPLING
- Sampling frequency: Days 2, 5, 7, 11, 14, 19, 25, 29
- Sampling method: Ba(OH)2 trap

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Toxicity control: yes

Reference substance:

benzoic acid, sodium salt

Test performance:

Reference substance (14 d): 66.1% degr.
Toxicity control (14 d): 75.4% degr.

Parameter:

% degradation (CO2 evolution)

Value:

53.8

St. dev.:

1.56

Sampling time:

14 d

Key result

Parameter:

% degradation (CO2 evolution)

Value:

72.1

St. dev.:

0.07

Sampling time:

28 d

Results with reference substance:

Reference substance (14 d): 66.1% degr.

Validity criteria fulfilled:

yes

Interpretation of results:

inherently biodegradable

Conclusions:

Based on 72.1% degradation after 28 days GDMP is not readily biodegradable.

Executive summary:

The biodegradation of GDMP was investigated over a 28-day period in a CO2 Evolution Test according to OECD guideline 301 B. The test medium was inoculated with activated sludge from a sewage treatment plant (secondary of Liede Sewage Treatment Plant of Guangzhou). The rate of degradation was monitored by measuring the carbon dioxide produced over the 28-d period. The test item was tested with a concentration of 31 mg/L in duplicates, corresponding to a carbon content (TOC) of 12.3 mg C/L in the test vessels. The biodegradation of the test item was followed by titrimetric analyses of the quantity of CO2 produced by the respiration of bacteria. The degradation was finished on day 28 by acidification, the last titration was made on day 29. After the soluble CO2 was turned out over a period of 24 h.

The percentage CO2 production was calculated in relation to the theoretical CO2 (ThCO2) of the test item. The biodegradation was calculated for each titration time.

To check the activity of the test system sodium benzoate was used as functional control. The percentage of degradation of the functional control reached the pass level of 60 % after 10 days.

In the toxicity control containing both test and reference item a biodegradation rate of 75.4% occurred within 14 days. The biodegradation of the reference item was not inhibited by the test item in the toxicity control.

Based on 72.1% degradation after 28 days GDMP is not readily biodegradable.

 

Description of key information

inherently biodegradable (72.1% degradation after 28 days)

Key value for chemical safety assessment

Biodegradation in water:

inherently biodegradable

Type of water:

freshwater

Additional information

The biodegradation of GDMP was investigated over a 28-day period in a CO2 Evolution Test according to OECD guideline 301 B. The test medium was inoculated with activated sludge from a sewage treatment plant (secondary of Liede Sewage Treatment Plant of Guangzhou). The rate of degradation was monitored by measuring the carbon dioxide produced over the 28-d period. The test item was tested with a concentration of 31 mg/L in duplicates, corresponding to a carbon content (TOC) of 12.3 mg C/L in the test vessels. The biodegradation of the test item was followed by titrimetric analyses of the quantity of CO2 produced by the respiration of bacteria. The degradation was finished on day 28 by acidification, the last titration was made on day 29. After the soluble CO2 was turned out over a period of 24 h.

The percentage CO2 production was calculated in relation to the theoretical CO2 (ThCO2) of the test item. The biodegradation was calculated for each titration time.

To check the activity of the test system sodium benzoate was used as functional control. The percentage of degradation of the functional control reached the pass level of 60 % after 10 days.

In the toxicity control containing both test and reference item a biodegradation rate of 75.4% occurred within 14 days. The biodegradation of the reference item was not inhibited by the test item in the toxicity control.

Based on 72.1% degradation after 28 days GDMP is not readily biodegradable.