1,2-epoxybutane

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1999-09-14 to 1999-11-30

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

GLP compliance:

yes

Specific details on test material used for the study:

- Name: 1,2-epoxybutane
- CAS no.: 106-88-7

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: stock solution stirred for about 48 hours in deionized water
- Controls: blank control without test item, procedure control using reference compound

Test organisms (species):

activated sludge, domestic

Details on inoculum:

- Activated sludge from laboratory wastewater plants treating municipal sewage
- The inoculum was washed, brought to a concentration of 5 g/L dry substance and aerated for about 24 hours
- 50 mL were added to a total volume of 250 mL to obtain a concentration of 1 g/L dry substance in the test

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

30 min

Test temperature:

20°C

Details on test conditions:

TEST SUBSTANCE
- preparation of the stock solution: test substance was stirred for about 48 hours in deionized water
- the test substance hydrolysed and the hydrolysate was tested
- summary parameters of the test substance:
theoretical organic carbon (ThOC): 667 mg/g
total organic carbon (TOC) before hydrolysis: 600 mg/g; pH = 7.5 (not adjusted)
dissolved organic carbon (DOC) before hydrolysis: 582 mg/g
total organic carbon (TOC) after 48 hours hydrolysis: 591 mg/g; pH < 5 (adjusted to 7.6)
dissolved organic carbon (DOC) after 48 hours hydrolysis: 575 mg/g
remark: the deviation of 10%-14% to the ThOC is probably due to the hydrolysis.

TEST CONDITIONS
- incubation time: 30 min
- test vessels: Erlenmeyer vessels
- test volume: 250 ml
- synthetic medium: 8ml/Vessel 100-fold concentrated OECD medium
- oxygen concentration during aeration: > 2.5 mg/l
- oxygen concentration immediately before measurement: > 6.5 mg/l
- duration of the measurement of oxygen consumption: 8-10 min

Reference substance (positive control):

yes

Duration:

30 min

Dose descriptor:

other: EC20

Effect conc.:

ca. 160 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Duration:

30 min

Dose descriptor:

other: EC80

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Key result

Duration:

30 min

Dose descriptor:

EC50

Effect conc.:

ca. 900 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Details on results:

VALIDITY CRITERIA
- deviation of blank controls <15%: yes
- EC50 of 3,5-dichlorophenol in the range of 5-30 mg/L: yes

Results with reference substance (positive control):

The EC50 (30 min) was determined to be ca. 7.0 mg/L.

Validity criteria fulfilled:

yes

Conclusions:

In an activated sludge respiration inhibition test, the EC50 was determined at 900 mg/L, based on nominal concentrations.

Reference 2

Endpoint:

toxicity to microorganisms

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

test procedure in accordance with national standard methods with acceptable restrictions

Qualifier:

according to guideline

Guideline:

DIN 38412-8 (Pseudomonas Zellvermehrungshemmtest)

GLP compliance:

no

Analytical monitoring:

no

Details on test solutions:

- Concentration of the stock solution: 12500 mg/L

Test organisms (species):

Pseudomonas putida

Details on inoculum:

- Pseudomonas putida
- Strain: DSM 50026

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

17 h

Test temperature:

20°C

Nominal and measured concentrations:

- Nominal test concentrations: 1250, 2500, 5000, 7500 and 10000 mg/L

Key result

Duration:

17 h

Dose descriptor:

EC10

Effect conc.:

2 920 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Key result

Duration:

17 h

Dose descriptor:

EC50

Effect conc.:

4 840 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Duration:

17 h

Dose descriptor:

other: EC90

Effect conc.:

7 350 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth inhibition

Validity criteria fulfilled:

not specified

Conclusions:

In an reproduction test with Pseudomomas putida, the EC50 was determined at 4840 mg/L and the EC10 was determined at 2920 mg/L, based on nominal concentrations.

Description of key information

The inhibition of the degradation activity of activated sludge is not anticipated when 1.2 -epoxybutane introduced in appropriate low concentrations.

Key value for chemical safety assessment

EC50 for microorganisms:

900 mg/L

Additional information

Key information

The toxicity of 1.2 -epoxybutane on microorganisms was tested in an respiration inhibition test with activated domestic sludge, according to OECD guideline 209 [BASF AG, 1999]. The 30-min EC50 for respiration inhibition was determined to be approximately ca. 900 mg/L 1.2 -epoxybutane.

 

Supporting information

Additional information on the toxicity to microorganisms are available from growth inhibition tests with Pseudomonas putida [BASF AG, 1988]. The 17 h EC10 values for the cell growth inhibition of Pseudomonas putida was 2920 mg/L.

 

Conclusion

Based on the most reliable information [BASF AG, 1999] the 30-min EC50 is considered ca. 900 mg/L. This result is supported by even higher effect values (7-hour EC10 = 2920 mg/L).