2,4,6-tri-n-propyl-2,4,6-trioxo-1,3,5,2,4,6-trioxatriphosphorinane

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:

1995-06-14 till 1995-06-21

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

Qualifier:

according to guideline

Guideline:

other: 88/302/EWG (Part C), EG Amtsblatt L 133 (1988) S.118 - 122

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Remarks:

Not possible, because the composition of the test water disturbs the analysis by paramagnetic effects

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: The test substance was dissolved in deionized water and the pH adjusted with NaOH from 2.0 to 7.1

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Name and location of sewage treatment plant where inoculum was collected: Domestic sewage treatment plant at Frankfurt am Main, Sindlingen
- Preparation of inoculum for exposure: Sediment from activated sewage sludge was centrifuged and washed for 3 times
- Pretreatment: not acclimatized to the test substance or the reference substance
- Initial biomass concentration: the content of dry mass was 4 g/L in the suspension and 1.6 g/L in the final test volume respectively

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

3 h

Test temperature:

20 ± 2 °C

pH:

7.2 ± 0.2

Nominal and measured concentrations:

Nominal concentration: 0 and 1000mg/L
no measured concentrations

Details on test conditions:

TEST SYSTEM
- Test vessel: 480 mL Beakers with magnetic stirrers
- Material, fill volume: glass, fill volume 200 mL
- Aeration: 50 litres per hour
- No. of vessels per concentration (replicates): 2
- No. of vessels per control (replicates): 3
- No. of vessels per reference control (replicates): 1
- Sludge concentration (weight of dry solids per volume): 1.6 g/L

OTHER TEST CONDITIONS
- Adjustment of pH: yes, with NaOH to pH 7.1

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorophenole

Key result

Duration:

3 h

Dose descriptor:

IC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Duration:

3 h

Dose descriptor:

NOEC

Effect conc.:

1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Details on results:

- Adsorption: no

Results with reference substance (positive control):

- Results with reference substance valid? yes, EC50 between 5 and 30 mg/L

Validity criteria fulfilled:

yes

Conclusions:

The test item was examined for toxicity to microorganisms in a 3-h static test according to OECD Guideline 209 and EG 88/302/EWG. The test item caused no inhibition of respiration up to a nominal concentration of 1000 mg/L. Thus, the 3-h IC50 was determined to be greater than 1000 mg/L.

Executive summary:

The toxicity of the test item to microorganisms (Activated sludge) was determined according to the OECD Guideline 209 and EG 88/302/EWG.

A static test was performed as a limit test with a concentration of 1000 mg/L. Inhibition of respiration was determined after 3 hours. The test substance undergoes fast hydrolysis in water with subsequent temperature and pH-dependent changes in the composition of the hydrolysis products. An analytical determination of the test compound or of the hydrolysis products in the test batches was not possible, because the composition of the test water disturbs the analysis by paramagnetic effects.

Test organisms exposed to 1000 mg/L of the test item showed no inhibition of respiration. Thus, the 3-h IC50 was determined to be greater than 1000 mg/L.

Description of key information

The test item was examined for toxicity to microorganisms in a 3-h static test according to OECD Guideline 209 and EG 88/302/EWG. The test item caused no inhibition of respiration up to a nominal concentration of 1000 mg/L. Thus, the 3-h IC50 was determined to be greater than 1000 mg/L and the NOEC 1000 mg/L.

Key value for chemical safety assessment

EC10 or NOEC for microorganisms:

1 000 mg/L

Additional information

The toxicity of the test item to microorganisms (Activated sludge) was determined according to the OECD Guideline 209 and EG 88/302/EWG.

A static test was performed as a limit test with a concentration of 1000 mg/L. Inhibition of respiration was determined after 3 hours. The test substance undergoes fast hydrolysis in water with subsequent temperature and pH-dependent changes in the composition of the hydrolysis products. An analytical determination of the test compound or of the hydrolysis products in the test batches was not possible, because the composition of the test water disturbs the analysis by paramagnetic effects.

Test organisms exposed to 1000 mg/L of the test item showed no inhibition of respiration. Thus, the 3-h IC50 was determined to be greater than 1000 mg/L.