2-Butanone, peroxide

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1989-10-19 to 1989-11-08

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

Version / remarks:

1984

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: EEC, 1988: "Official Journal of the European Communities" L 133, Part C, Methods for the determination of ecotoxicity, biodegradation, activated sludge respiration inhibition test. (1988.05.30) 118 - 122

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

not required

Vehicle:

no

Details on test solutions:

The test substance was added to the vessels using a stock solution of 519 mg/L.

Test organisms (species):

sewage, domestic

Details on inoculum:

Secondray activated sludge was collected from the RZWI Nieuwgraaf in Duiven. This activated sludge plant predominatly treats domestic wastewater.
The actived sludge concentration in the incubation vessels was 0.7 g dry weight/L.

Water media type:

freshwater

Limit test:

no

Total exposure duration:

30 min

Remarks on exposure duration:

contact time

Test temperature:

20 °C

pH:

7.7 - 7.9

Dissolved oxygen:

The respiration rates were 0.17 - 0.17 mg O2/L min.

Nominal and measured concentrations:

The test concentrations were 5.0, 10.0, 20.0, 40.0, 80.0 mg/L.

Details on test conditions:

The homogenized sludge was incubated in a shaking water bath (100 Hz, 20 °C) for 30 minutes with various concentrations of the test compound and synthetic sewage.

Reference substance (positive control):

yes

Remarks:

2, 4, 5 - Trichlorophenol

Key result

Duration:

30 min

Dose descriptor:

EC50

Effect conc.:

48 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Remarks on result:

other: 95% CI: 37 - 70 mg/L

Key result

Duration:

30 min

Dose descriptor:

EC10

Effect conc.:

12 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Details on results:

The validity of the test is shown by two important criteria. Firstly, the control respiration rates are within 7 % of each other and secondly, the EC50 of the reference compound is within the described range ( 5 - 30 mg/L). The pH of the reaction mixture before the respiration varies from 7.7 to 7.9.

Results with reference substance (positive control):

The EC50 of the reference Compound is within the decribed range (5 - 30 mg/L). (Details of the respiration rates see "Remarks on results including tables and figures".

Reported statistics and error estimates:

Ec values were computed from the best fitted straight line (least square method) through the point given by the probit of the percentage inhibitation and logarithm of the concentration of the test substance. Confidence limits were computed based on Fiellers`s theorem. All computations were performed with the software package SAS.

Table1: Respiration rates of the activated sludge (Rs) and inhibition percentage calculated at various concentrations of the test compound

Concentration (mg/L)	pH start	Respiration rate (mg O2/L min)	Inhibition (%)
Control (Rc1)	7.7	0.45	-
Control (Rc1)	7.8	0.42	-
5.0	7.8	0.43	1
10.0	7.8	0.40	8
20.0	7.8	0.32	26
40.0	7.8	0.23	47
80.0	7.9	0.17	61

 

Table2: Respiration rates of the activated sludge and inhibition percentage calculated at various concentrations of 2,4,5 trichlorophenol

Concentration (mg/L)	pH start	Respiration rate (mg O2/L min)	Inhibition (%)
Control	7.7	0.43	-
Control	7.8	0.41	-
5.0	7.8	0.41	3
10.0	7.8	0.25	41
20.0	7.8	0.12	71
40.0	7.9	0.06	86

Validity criteria fulfilled:

yes

Conclusions:

The EC50 of methyl ethyl ketone peroxide in DMP for activated sludge (the concentration with 50 % inhibition of the respiration in comparison to the control) is 48 mg/L with 95 % confidence limits of 37 and 70 mg/L. The EC10, EC20 and EC80 are 12, 20 and 120 mg/L, respectively.

Executive summary:

The respiration rate after an incubation of methyl-ethylketone peroxide in DMP was measured for a period of 30 minutes in an activated sludge respiration inhibition test according OECD guideline 209.

The EC50 of methyl ethyl ketone peroxide for activated sludge (the concentration with 50 % inhibition of the respiration in comparison to the control) is 48 mg/L with 95 % confidence limits of 37 and 70 mg/L. The EC10, EC20 and EC80 are 12, 20 and 120 mg/L, respectively.

Description of key information

Methyl-ethylketone peroxide in DMP was assessed in an activated sludge respiration inhibition test, according to EU-method C.11 and OECD 209. The EC50 was determined at 48 mg/L and the EC10 was determined at 12 mg/L.

Key value for chemical safety assessment

EC50 for microorganisms:

48 mg/L

EC10 or NOEC for microorganisms:

12 mg/L

Additional information

The respiration rate after an incubation of methyl-ethylketone peroxide in DMP was measured for a period of 30 minutes in an activated sludge respiration inhibition test according OECD guideline 209.

The EC50 of methyl ethyl ketone peroxide for activated sludge (the concentration with 50 % inhibition of the respiration in comparison to the control) is 48 mg/L with 95 % confidence limits of 37 and 70 mg/L. The EC10, EC20 and EC80 are 12, 20 and 120 mg/L, respectively.