trans-dichloroethylene

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Data taken from accepted publication with limited details on methods and results. This study was selected as the key study because the information provided for the hazard endpoint is sufficient for the purpose of classification and labelling and/or risk assessment.

Data source

Reference

Reference Type:

publication

Title:

Biodegradability studies with organic priority pollutant compounds

Author:

Tabak HH, Quave SA, Mashni CI, and Barth EF

Year:

1981

Bibliographic source:

J WPCF, 53(10):1503-1518

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

Deviations:

yes

Remarks:

3 bottles per concentration; volatile fraction also captured and measured

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

trans-dichloroethylene

EC Number:

205-860-2

EC Name:

trans-dichloroethylene

Cas Number:

156-60-5

Molecular formula:

C2H2Cl2

IUPAC Name:

(1E)-1,2-dichloroethene

Details on test material:

- Purity: not reported

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge: settled domestic wastewater as microbial inoculum

Duration of test (contact time):

28 d

Initial test substance concentration

Initial test substance concentration 1

Initial conc.:

5 mg/L

Based on:

test mat.

Initial test substance concentration 2

Initial conc.:

10 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation 1

Parameter followed for biodegradation estimation:

test mat. analysis

Parameter followed for biodegradation estimation 2

Parameter followed for biodegradation estimation:

TOC removal

Details on study design:

TEST CONDITIONS
- Composition of medium: biochemical oxygen demand (BOD) dilution water containing 5 mg of yeast extract per litre, as the synthetic medium
- Test temperature: 25°C
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: 250-mL glass-stoppered reagent bottles
- Test performed in closed vessels due to significant volatility of test substance: yes
- Number of culture flasks/concentration: 3

SAMPLING
- Sampling frequency: every 7 days

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Abiotic sterile control: yes
- Other: Volatility controls, utilizing a nonbiological system (medium-test compound without inoculum) were held at both refrigerated and 25°C holding temperatures for 10 days and then analysed by GC and for TOC to determine loss of substrate from volatilization.

Reference substance

Reference substance:

other: Phenol

Results and discussion

% Degradation

% Degradation 1

Parameter:

% degradation (test mat. analysis)

Value:

67

Sampling time:

7 d

Remarks on result:

other: 5 mg/L test

% Degradation 2

Parameter:

% degradation (test mat. analysis)

Value:

95

Sampling time:

28 d

Remarks on result:

other: 5 mg/L test

% Degradation 3

Parameter:

% degradation (test mat. analysis)

Value:

40

Sampling time:

7 d

Remarks on result:

other: 10 mg/L test

% Degradation 4

Parameter:

% degradation (test mat. analysis)

Value:

93

Sampling time:

28 d

Remarks on result:

other: 10 mg/L test

% Degradation 5

Parameter:

% degradation (test mat. analysis)

Value:

33

Sampling time:

10 d

Remarks on result:

other: percent loss from 5 mg/L non-biologic control due to volatility

Details on results:

The test item exhibits slow biodegradative activity concomitant with relatively moderate rate of volatilization established in the non-biological volatility control systems. The test item was shown to be significantly biodegradable with gradual adaptation observed. The relatively significant volatilization in the non-biological volatility control series did not preclude the biodegradative activity of microbiota in culture media from the relatively high total percentage of loss of test item throughout the study in comparison to the volatility percentage losses.

BOD5 / COD results

Results with reference substance:

Phenol in the 5 and 10 mg/L positive control degraded 100% by Day 14.

Any other information on results incl. tables

			Average total loss (% biodegradation) of test item in 7 day intervals				Volatile Loss (%) 10 Days
Test Item	mg/mL	Degradation summary	Day 7	Day 14	Day 21	Day 28	5°C	25°C
Phenol (reference)	5	D	96	100	100	100	-	-
Phenol (reference)	10	D	97	100	100	100	-	-
Test Item	5	B	67	79	88	95	0	33
Test Item	10	B	40	76	81	93	0	26
D Significant degradation with rapid adaptation. B Slow to moderate biodegradative activity, concomitant with significant rate of volatilization.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

other: slow biodegradative activity concomitant with relatively moderate rate of volatilization

Conclusions:

This study and the conclusions which are drawn from it fulfil the quality criteria (validity, reliability, repeatability).
The test item exhibits slow biodegradative activity concomitant with relatively moderate rate of volatilization.

Executive summary:

The biodegradability test method used in the study was the static-culture flask-screening procedure using 5- and 10- mg/L concentrations of the test item with a 7-day static incubation followed by three weekly subcultures (total incubation of 28 days. Volatility controls, utilizing a non-biological system (medium and test compound without inoculum) were held at both refrigerated and 25°C holding temperatures for 10 days and then analysed by GC and for TOC to determine loss of the test item from volatilization.

For the 5 mg/mL concentration the 28 day percent total loss of compound was 95%. The volatilization loss was 33%.  In the 10 mg/mL test, total loss was 93% with a 26% loss due to volatilization. The test item exhibits slow biodegradative activity concomitant with relatively moderate rate of volatilization established in the non-biological volatility control systems.  The test item was shown to be significantly biodegradable with gradual adaptation observed. The relatively significant volatilization in the non-biological volatility control series did not preclude the biodegradative activity of microbiota in culture media from the relatively high total percentage of loss of test item throughout the study in comparison to the volatility percentage losses.