2,3-dichlorobuta-1,3-diene

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2010-03-18 till 2010-03-26

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline and GLP-compliant study.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

2,3-dichloro-1,3-butadiene

IUPAC Name:

2,3-dichloro-1,3-butadiene

Constituent 2

Reference substance name:

2,3-dichlorobuta-1,3-diene

EC Number:

216-721-0

EC Name:

2,3-dichlorobuta-1,3-diene

Cas Number:

1653-19-6

Molecular formula:

C4H4Cl2

IUPAC Name:

2,3-dichlorobuta-1,3-diene

Constituent 3

Reference substance name:

2,3-dichlorobutadiene-1,3

IUPAC Name:

2,3-dichlorobutadiene-1,3

Details on test material:

Partie number - Q101
Sample number - 1152
Purity - not stated

Specific details on test material used for the study:

Details on properties of test surrogate or analogue material (migrated information):
Not applicable

Sampling and analysis

Analytical monitoring:

no

Details on sampling:

Not applicable

Test solutions

Vehicle:

no

Test organisms

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

Collected from the aeration tank of a domestic sewage treatment plant, Cologne- Stammheim. The sludge was allowed to settle and the supernatant was decanted. After centrifuging for 15 minutes at 3500 - 4500 rpm at 20 °C the supernatant was decanted. The required amount of sludge to achieve a 3 g/L (dry weight) of suspended solids was calculated and the required amount of sludge was made up to volume with deionised water. The sludge was stored at 20 ± 2°C, aerated and fed daily with synthetic medium until used.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Post exposure observation period:

Not applicable

Test conditions

Hardness:

Not applicable

Test temperature:

Test temperature range during the study was 19.7 - 19.9 °C

pH:

pH range in the definitive study was 7.5 - 7.6

Dissolved oxygen:

Results of dissolved oxygen measurements are presented in the results section.

Salinity:

Not applicable

Nominal and measured concentrations:

Nominal exposure concentrations were 100, 180, 320, 560 and 1000 mg/L.

Details on test conditions:

The study was performed in 300 mL glass Erlenmeyer flasks. The incubation time was 30 minutes with permanent aeration.

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Effect concentrations 2

Duration:

3 h

Dose descriptor:

EC10

Effect conc.:

163.8 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Remarks on result:

other: 7.9 - 301.4 mg/L

Results with reference substance (positive control):

The reference study was conducted using 3,5-dichlorophenol using nominal exposure concentrations of 2.5, 5.0, 10, 20 and 40 mg/L. Inhibition of respiration was 5.9, 12.3, 41.7, 75.4 and 89.1% in the 2.5, 5.0, 10, 20 and 40 mg/L nominal treatments. The 3 h EC50 for 3,5-dichlorophenol was for 12.0 mg/L, this is within the range 5 - 30 mg/L required in the guideline.

Reported statistics and error estimates:

The EC50 value of 2,3-dichlorobutadiene-1,3 was determined by observation of the data.

Any other information on results incl. tables

Respiration rates and percentage inhibition

Treatment	Nominal concentration (mg/L)	Respiration rate (mg O2/L/h)	% inhibition
Control 1	0	24.9	-
Control 2	0	24.0	-
Control mean	-	24.4	-
% difference in controls	-	3.6	-
3,5-DCP	2.5	23.0	5.9
	5	21.4	12.3
	10	14.3	41.7
	20	6.0	75.4
	40	2.7	89.1
2,3-dichlorobutdiene-1,3	100	22.0	9.9
	180	21.8	11.0
	320	19.5	20.2
	560	18.9	22.8
	1000*	12.9	47.4

* the physico-chemical oxygen consumption has been determined at 4000 mg/L test item concentration. As no physic-chemical oxygen consumption was observed at the that test item concentration this observation also holds true for the lower test item concentrations.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The toxicity of 2,3-dichlorobutadiene-1,3 to activated sewage sludge was investigated in a respiration inhibition test according to EU Method C11 Activated sludge respiration inhibition 2008. Following three hours exposure to 2,3-dichlorobutadiene-1,3 the EC50 was observed to be > 1000 mg/L (based on nominal exposure concentrations), the corresponding EC10 was calculated to be 163.8 mg/L.

Executive summary:

The toxicity of 2,3-dichlorobutadiene-1,3 to activated sewage sludge was investigated in a respiration inhibition test according to EU Method C11 Activated sludge respiration inhibition 2008. Following three hours exposure to 2,3-dichlorobutadiene-1,3 the EC₅₀was observed to be > 1000 mg/L (based on nominal exposure concentrations), the corresponding EC₁₀was calculated to be 163.8 mg/L.