Reaction products of 2-methylimidazole and 2,2'-[(1-methylethylidene)bis(4,1-phenyleneoxymethylene)]bisoxirane

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was conducted according to the O.E.C.D. test guideline 209 with GLP compliance.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2012

Report date:

2012

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Reaction products of 2-methylimidazole and 2,2'-[(1- methylethylidene)bis(4,1-phenyleneoxymethylene)]bisoxirane

EC Number:

701-436-0

Molecular formula:

(C15H16O2.C4H6N2.C3H5ClO)x

IUPAC Name:

Reaction products of 2-methylimidazole and 2,2'-[(1- methylethylidene)bis(4,1-phenyleneoxymethylene)]bisoxirane

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

As per IUCLID5 Sections 1.1. 1.2. 1.4. and 4.1.

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

The control, test, abiotic control and reference sample solutions were measured for dissolved oxygen content independently in series such that each bottle was measured immediately after the expiration of the three hour contact time.

Test solutions

Vehicle:

no

Details on test solutions:

The test substance was directly weighed into the test vessels. The test substance was added to 234 mL of deionized water in a quantity appropriate for the desired concentration. Sixteen mL of synthetic sewage feed and 250 mL of microbial inoculum (activated sludge) were added to each test bottle.

Test organisms

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

A sample of activated sludge was obtained from the Brazos River Authority in Sugar Land, TX and aerated when during fransport and storage. In preparation the sludge was washed three times, with a settling time of—20 minutes between each wash.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Post exposure observation period:

None

Test conditions

Hardness:

No data

Test temperature:

25° C

pH:

7.2

Dissolved oxygen:

1.0 mg/L

Salinity:

0.63 ppt

Nominal and measured concentrations:

10, 100 and 1000 mg/L nominal.

Details on test conditions:

The study was conducted in 300 mL Biological Oxygen Demand (BOD) bottles. Two blanks were conducted during the study for toxicity comparison. Each blank was prepared by bringing 250 mL of activated sludge and 16 mL of synthetic sewage feed to 500 mL volume with deionized water. The Synthetic sewage was prepared using 16 g peptone, 11 g meat extract, 3 g urea, 0.7 g sodium chloride, 0.4 g calcium chloride dihydrate, 0.2 g magnesium sulfate heptahydrate, and 2.8 g dipotassium hydrogen phosphate in 1 L of deionized water.

The Reference Standard (positive control) was 3,5-dichlorophenol at 5, 10, 20 and 40 mg/L. The Abiotic controls were prepared without the activated sludge.

The control, test substance, abiotic control and reference sample solutions were measured for dissolved oxygen content independently in series such that each bottle was measured immediately after the expiration of the three hour contact time.

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorophenol.

Results and discussion

Effect concentrations

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 mean relative percent inhibition of the activated sludge respiration by the test substance was 18.5% at the high concentration og 1000 mg/L.

Results with reference substance (positive control):

The relative percent inhibition of the activated sludge respiration was 11.2-11.6 % at concentrations of 5 and 10 mg/L. Relative percent inhibition was 40.7 % at 20 mg/L and 83.2 % and 40 mg/L. The EC50 for the positive control 3,5-dichhlorophenol was 24.4 mg/l with 95 % confidence limits of 8.4-36.8 mg/L.

Reported statistics and error estimates:

Linear interpolation was applied to estimate the positive control EC50 value. The positive control 95 % confidence limits were 8.4-36.8 mg/L.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The test substance had an EC50 value of > 1000 mg/L for the inhibition of activated sludge respiration. Therefore, the test substance will have little or no impact upon the operation of sewage treatment plants.

Executive summary:

The test substance, Bisphenol A, epichlorohydrin polymer, 2-methylimidazole condensate, was evaluated for its impact upon activated sludge respiration in an O.E.C.D. test guideline 209 study. The test substance had an EC50 value of > 1000 mg/L for the inhibition of activated sludge respiration. Therefore, the test substance will have little or no impact upon the operation of sewage treatment plants.