Reaction products of pentaerythritol, propoxylated and 1-chloro-2,3-epoxypropane with hydrogen sulfide

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:

14 -15 April 2010

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

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

not required

Vehicle:

no

Details on test solutions:

The test substance was directly weighed out in each test vessel. After 24h of stirring the test substance was completely dispersed.

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Origin: Municipal sewage treatment plant of D-31157, Sarstedt Germany
- Preparation of inoculum for exposure:
- Pretreatment: The sludge was washed twice with autoclaved tap water and adjusted corresponding to a dry weight of 4.0 g/L ± 10%. The sludge was used within 24 h after sampling.
- Dry sludge concentration: 3.97 g/L

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Hardness:

Not reported

Test temperature:

20.9 °C

pH:

6.89

Dissolved oxygen:

5.2 - 7.7 mg O2/L (determined at the start of the measurement)

Nominal and measured concentrations:

Nominal concentrations: 0 (control), 100, 180, 320, 580 and 1000 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 500 mL Erlenmeyer flasks
- Aeration: Permanent
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 2

TEST MEDIUM / WATER PARAMETERS
Composition of the test medium:
200 mL inoculum
16 mL synthetic waste water
284 mL autoclaved tap water
test item concentration (directly weighed out in each test vessel)


EFFECT PARAMETERS MEASURED:
The oxygen depletion of the control, reference and test item replicates was measured after 3 hours incubation by means of an oximeter and recorded for at least 3 minutes on a flat bed recorder.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 1.8
- Range finding study: Yes
- Test concentrations: 0 (control), 10, 100 and 1000 mg/L
- Results used to determine the conditions for the definitive study: 0% inhibition at 10 mg/L, 4% inhibtion at 100 mg/L and 18% at 1000 mg/L

Reference substance (positive control):

yes

Remarks:

copper (II) sulphate pentahydrate

Key result

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

Details on results:

The EC10 is estimated by the reviewer to be 1000 g/L (11% inhibition at 1000 mg/L and 9% inhibition at 580 mg/L).

Results with reference substance (positive control):

The 3h-EC50 of the refence substance copper (II) sulphate pentahydrate was 103 mg/L which is within the recommended confidence range of 54 - 156 mg/L

Table: Respiration rates and inhibition of respiration of test and reference item concentrations.

Treatment	Concentration (mg/L)	Respiration rate (mg O2/L/h)	Inhibition (%)
Test item	1000	28.0	11
	580	28.8	9
	320	31.6	0
	180	30.0	5
	100	32.8	-4
Control	-	31.2	-
	-	32.0	-
Reference item	180	9.2	71
	100	14.8	53
	58	23.6	25

 

Validity criteria fulfilled:

yes

Remarks:

The two control respiration rates differ not more than 15% in the study. The 3h-EC50 of copper (II) sulphate pentahydrate is within the accepted range of 54-156 mg/L.

Conclusions:

The 3h-EC50 of the test substance to activated sludge was > 1000 mg/L
The 3h-EC10 of the test substance to activated sludge, estimated by the reviewer was 1000 mg/L

Executive summary:

The toxicity of the test substance to activated sludge was investigated according to OECD guideline 209 and GLP.

The 3h-EC50 of the test substance to activated sludge was > 1000 mg/L

The 3h-EC10 of the test substance to activated sludge, estimated by the reviewer (based on 11% inhibition at 1000 mg/L and 9 % inhibition at 580 mg/L) was ca. 1000 mg/L.

Because the test was carried out according to OECD209 and GLP an no shortcomings were observed a reliability 1 was assigned.

Description of key information

The 3h-EC50 of the test substance to activated sludge was > 1000 mg/L.
The 3h-EC10 of the test substance to activated sludge, estimated by the reviewer was 1000 mg/L.

Key value for chemical safety assessment

EC50 for microorganisms:

1 000 mg/L

Additional information

The toxicity of the test substance to activated sludge was investigated according to OECD guideline 209 and GLP.

The 3h-EC50 of the test substance to activated sludge was > 1000 mg/L.

The 3h-EC10 of the test substance to activated sludge, estimated by the reviewer (based on 11% inhibition at 1000 mg/L and 9 % inhibition at 580 mg/L) was ca. 1000 mg/L. Based on the fact that this is an estimation, the worst-case EC50 value of 1000 mg/L is taken as key value for the CSA.

Since the test was carried out according to OECD209 and GLP, and because no shortcomings were observed a reliability 1 was assigned.