2H-Azepin-2-one, hexahydro-, polymer with 1,6-diisocyanatohexane

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:

2007-06-26 to 2007-07-16

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Guideline study with acceptable restrictions: high concentration of solvent, no substance specific analytical monitoring

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Version / remarks:

(1984)

Deviations:

no

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

(1988)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

The test substance was directly weighed into Erlenmeyer flasks (incubation vessel) and stirred test item for 16 hours before start of incubation time.

Test organisms (species):

activated sludge

Details on inoculum:

The sludge originated from the aeration tank of a domestic sewage treatment plant (municipal STP Cologne-Stammheim). The sludge was aerated before use and daily fed with synthetic medium. Concentration of the activated sludge: 960 mg/L suspended solids

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test temperature:

20 ± 2° C

pH:

6.9

Nominal and measured concentrations:

nominal: 10, 100 and 1000 mg/L
concentration of reference substance: 5, 10 and 20 mg/L

Reference substance (positive control):

yes

Remarks:

3.5-Dichlorophenol

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:

Test concentration Inhibition [%]
10 mg/L 0
100 mg/L 0
1000 mg/L 0

Results with reference substance (positive control):

Test concentration Inhibition [%]
5 mg/L 24.2
10 mg/L 55.8
20 mg/L 88.3

Validity criteria fulfilled:

yes

Conclusions:

The test item showed no toxic effects on microorganisms (0% respiration inhibition) at a concentration of 1000 mg/L, corresponding to 720 mg 2H-Azepin-2-one, hexahydro-, polymer with 1,6-diisocyanatohexane/l. The EC50 of 2H-Azepin-2-one, hexahydro-, polymer with 1,6-diisocyanatohexane is therefore above 720 mg/L.

Executive summary:

A study was performed to assess the toxicity ofa 72 % solution of 2H-Azepin-2-one, hexahydro-, polymer with 1,6-diisocyanatohexane in 2-methoxy-1-methylethylacetateto bacteria. The study was conducted in accordance with the Commission Directive 88/302/EEC; Official Journal of the EG L133 Part C.11 (1988) and OECD Guideline 209 “Activated Sludge, Respiration Inhibition Test” (1984). The activated sludge was exposed to the test item at concentrations of 10, 100 and 1000 mg/L. The respiration rate of each mixture was determined after an aeration period of 3 hours. The test item showed 0.0 % respiration inhibition of activated sludge at a test item concentration of 1000 mg/L. The EC50 is higher than 1000 mg test item/L, corresponding to 720 mg2H-Azepin-2-one, hexahydro-, polymer with 1,6-diisocyanatohexane/L. The effect value related to nominal concentration, since no analytical monitoring was performed.

Description of key information

A study was performed to assess the toxicity of a 72 % solution of 2H-Azepin-2-one, hexahydro-, polymer with 1,6-diisocyanatohexane in 2-methoxy-1-methylethylacetate to bacteria. The study was conducted in accordance with the Commission Directive 88/302/EEC; Official Journal of the EG L133 Part C.11 (1988) and OECD Guideline 209 “Activated Sludge, Respiration Inhibition Test” (1984). The activated sludge was exposed to the test item at concentrations of 10, 100 and 1000 mg/L. The respiration rate of each mixture was determined after an aeration period of 3 hours. The test item showed 0.0 % respiration inhibition of activated sludge at a test item concentration of 1000 mg/L.

Key value for chemical safety assessment

EC50 for microorganisms:

1 000 mg/L

EC10 or NOEC for microorganisms:

1 000 mg/L

Additional information

The EC50 is higher than 1000 mg test item/L, corresponding to 720 mg 2H-Azepin-2-one, hexahydro-, polymer with 1,6-diisocyanatohexane/L. The effect value related to nominal concentration, since no analytical monitoring was performed and the substance is poorly water soluble.