Trimorpholinophosphine oxide

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Dec 18, 2001 - Apr 02, 2002

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2002

Report date:

2002

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Principles of method if other than guideline:

none

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Trimorpholinophosphine oxide

EC Number:

224-662-7

EC Name:

Trimorpholinophosphine oxide

Cas Number:

4441-12-7

Molecular formula:

C12H24N3O4P

IUPAC Name:

trimorpholinophosphine oxide

Test material form:

solid

Sampling and analysis

Analytical monitoring:

no

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: 1000 mg lest item were dissolved in 200 mL deionized water. Thus, a concentration of 5.0 g/L was obtained.

Test organisms

Test organisms (species):

activated sludge, domestic

Details on inoculum:

Species: activated sludge, micro organisms from a domestic waste water treatment plant.
Origin: supplied by the sewage plant Groß Zimmern, Germany

The sludge was washed by centrifugation and the supernatant liquid phase was decanted. The solid material was resuspended in tap water and centrifuged again. The latter procedure was repeated twice. An aliquot of the final sludge suspension was weighed, dried and the ratio of wet sludge (g) to its dry weight (g) determined. Based on this ratio, calculated aliquots of washed sludge suspension, corresponding to 3 g dry material/L were made up with tap water. The pH of the activated sludge was determined to be 7.8. The activated sludge was used directly after adjustment without storage.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test conditions

Hardness:

250 mg/L

Test temperature:

19 - 20 °C

pH:

saturated (7-8 mg/L)

Dissolved oxygen:

>2.5 mg O2/L

Nominal and measured concentrations:

0, 10, 32, 100, 320, 1000 mg/L nominal (test material)
0, 3.2, 10, 32 mg/L nominal (reference 3,5-Dichlorophenol)

Details on test conditions:

Measurement of Respiration Rate:
For the measurement of the respiration rate a well-mixed sample of each test medium was poured into a Karlsruher flask after exactly 3 hours incubation time, and was not further aerated. The oxygen concentration was measured with an oxygen electrode, and was recorded for about ten minutes. During measurement, the samples were continuously stirred on a magnetic stirrer.
The oxygen consumption (in mg 02 per L per minute) was determined from the most linear part of the respiration curve.

Measurement of pH, dissolved oxygen and water temperature:
The pH and the oxygen concentrations were determined at the start and at the end of the incubation period in all treatments. The water temperature was measured in one control medium at the start and at the end of the incubation period.

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorophenol

Results and discussion

Effect concentrations

Effect concentrations 1

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

Effect concentrations 2

Key result

Duration:

3 h

Dose descriptor:

EC10

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Details on results:

Inhibition of respiration rate:
In comparison to the inoculum controls the respiration rate of the activated sludge was not inhibited (-4.9%) at the lowest concentration of 10 mg/L. At the nominal concentrations of 32 and 320 mg/L, the respiration rate was inhibited by 8.7%. St the highest nominal test concentration of 1000 mg/L an inhibition rate of 16.5% was determined. The test item concentrations exceeding 1000 mg/L were not tested.

3-hour EC20 and 3-hour EC50:
Based on measured inhibition rates, the 3-hour EC20 and EC50 could not be quantified, because up to the highest nominal test concentration (1000 mg/L) less than 20% inhibition was noted after 3 hours of incubation. Nevertheledd, the 3-hour EC20 and EC50 are clearly higher than 1000 mg/L nominal under the experimental conditions chosen.

Results with reference substance (positive control):

Inhibition of respiration rate:
In comparison to the controls the respiration rate of the activated sludge was moderately inhibited by 34% at the lowest nominal concentration of 3.2 mg/L. At the nominal concentrations of 10 and 32 mg/L, the respiration rate was inhibited by 67% and 88.4%, respectively.

3-hour EC20 and 3-hour EC50:
The 3-hour EC50 of 3,5-Dichlorophenol was calculated to be 6.0 mg/L with 95% confidence limits from 2.0 to 9.0 mg/L.

Any other information on results incl. tables

The influence of the test item on the activity of activated sludge was evaluated by measuring the respiration rate under defined conditions. The respiration rate (oxygen consumption) of an aerobic activated sludge fed with a standard amount of synthetic sewage was measured in the presence of various concentrations (10, 32, 100, 320 and 1000 mg/L) of the test item after an incubation period of 3 hours. This study was conducted according to Good Laboratory Practice (GLP) and the method applied followed the OECD Guideline for Testing of Chemicals, Section 2, No.209: "Activated Sludge, Respiration Inhibition Test", adopted April 04, 1984.

In comparison to the inoculum controls, the respiration rate of the activated sludge was inhibited by up to 16.5% at a tested concentration of nominal 1000 mg/L. Higher concentrations were not tested. Based on measured inhibition rates, the 3 hour EC20 and EC50 values of the test item could not be quantified as the inhibition at the highest nominal concentration of 1000 mg/L was less than 20%. However, the 3 -hour EC20 and EC50 are clearly higher than 1000 mg/L.

The 3 -hour EC50 of the test material was higher than 1000 mg/L under the present test conditions.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes