3,3'-methylenebis[5-methyloxazolidine]

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1992

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Remarks:

Study according to guideline (OECD 209).

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1992

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Version / remarks:

(dated 04.04.1984)

Deviations:

yes

Remarks:

ph value is not reported

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

3,3'-methylenebis[5-methyloxazolidine]

EC Number:

266-235-8

EC Name:

3,3'-methylenebis[5-methyloxazolidine]

Cas Number:

66204-44-2

Molecular formula:

C9H18N2O2

IUPAC Name:

3,3'-methylenebis[5-methyloxazolidine]

Details on test material:

- Test material: Reaction products of paraformaldehyde and 2-hydroxypropylamine (ratio of 3:2)
- Charge No. 620251
- Specification: MAR 71

Sampling and analysis

Analytical monitoring:

no

Test organisms

Test organisms (species):

activated sludge

Details on inoculum:

- Nature: Activated sludge
- Source: sewage treatment plant
- Sampling site: Stellinger Moor, Hamburg (Germany)
- Laboratory culture: No
- Method of cultivation: Not applicable
- Preparation of inoculum for exposure: Sludge diluted with 5% (v/v) synthetic waste water, aerated overnight and used without further pretreatment
- Pretreatment: None

Study design

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test conditions

Test temperature:

20 ± 1°C

Nominal and measured concentrations:

Nominal concentrations: 10, 20, 50, 100, 300 mg/L + control

Details on test conditions:

CULTURE MEDIUM
- 8 mL synthetic sewage were diluted to 150 mL with tap water, then 100 mL microbial inoculum were added

TEST SYSTEM
- Number of culture flasks/concentration: 1
- Aeration device: Membrane pump
- Measuring equipment: O2-electrode
- Test performed in closed vessels due to significant volatility of TS: No

OTHER TEST CONDITIONS
- Suspended solids concentration: 3.09 g/L filtratable solids

TEST PARAMETER
- Respiration rate (Measurement of dissolved oxygen concentration)
- After 3 h respiration rate measured over 10 min with oxygen electrode

CONTROLS
- 2 blank controls (without test substance), each 1 at the beginning and at the end of test

STATISTICS
- EC50 taken from concentration-response curve

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Results and discussion

Effect concentrations

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

44 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Details on results:

- No other effects observed

Results with reference substance (positive control):

- Concentrations: 10, 20, 30, 40, 50 mg/L + control (nominal concentrations)
- Results: 3 h-EC50 = 9 mg/L

Reported statistics and error estimates:

Deviation of respiration in controls ± 2%

Any other information on results incl. tables

Concentration (mg/L)	Respiration rate (mg O2/L*min)	Inhibition (%)
Control	0.87	-2
10	0.76	10
20	0.74	13
50	0.36	58
100	0.11	87
300	0.03	96

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The substance is harmful towards bacteria.

Executive summary:

The substance was found to be toxic towards sewage sludge microorganisms.

A clear concentration-response relationship can be established from the study results. At 10 mg/L respiration was inhibited by 10%, compared to the control. At 50 mg/L respiration was inhibited by 58%, while at the highest applied concentration inhibition was nearly total.The EC50 was determined at 44 mg/L.

The test is considered as valid as the validity criteria given in OECD 209 (as adopted 1981) were met: a) the difference of the duplicate controls was within a range of 15%; b) the sensitivity of the activated sludge towards the reference substance was within the accepted range (EC50 between 5 and 30 mg/L).

The constituents of the reaction product (substance) are not volatile from aqueous solutions, therefore this removal mechanism could not influence the test results. It is not expected that the the low adsorptivity of the test substance influenced test substance concentrations.

The constituents of the reaction product (substance) hydrolyse completely in concentrations which are expected to occur in waste waters and surface waters. Also in the media of toxicity tests, complete hydrolysis is expected, Therefore, the observed effects are assumed to be caused by a mixture of hydrolysis products.