Dibutyl hydrogen phosphate

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:

1988-02

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

GLP compliance:

yes

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

laboratory scale sewage treatment plant treating synthetic sewage (OECD 209)

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test temperature:

20.4

pH:

8.4

Dissolved oxygen:

start: 3.2 mg
end: 2.3 mg

Nominal and measured concentrations:

nominal: 100, 1000 and 10000 mg/L

Details on test conditions:

- test concentration of activated sludge: 6 g/L (dry matter)

Reference substance (positive control):

yes

Remarks:

3,5-Dichlorophenole

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 10 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Validity criteria fulfilled:

yes

Conclusions:

According to the OECD Guideline 209 dibutyl hydrogen phosphate was exposed to activated sludge of a predominantly domestic sewage. An 3h-EC50 of > 10000 mg/L was obtained.

Executive summary:

A study was performed to assess the toxicity of dibutyl hydrogen phosphate to microorganisms. The study was conducted according to the OECD Guideline 209. The activated sludge was exposed to dibutyl hydrogen phosphate at different concentrations. The respiration rate of each mixture was determined after aeration periods of 3 hours. Dibutyl hydrogen phosphate showed no respiration inhibition of activated sludge at a concentration of 10000 mg/L. The EC50 is higher than 10000 mg/L.

The effect value related to nominal concentration, since no analytical monitoring was performed.

Description of key information

Dibutyl hydrogen phosphate was exposed to activated sludge of a predominantly domestic sewage. An 3h-EC50 of > 10000 mg/L was obtained.

Key value for chemical safety assessment

EC50 for microorganisms:

10 000 mg/L

Additional information

A study was performed to assess the toxicity of dibutyl hydrogen phosphate to microorganisms. The study was conducted according to the OECD Guideline 209. The activated sludge was exposed to dibutyl hydrogen phosphate at different concentrations. The respiration rate of each mixture was determined after aeration periods of 3 hours. Dibutyl hydrogen phosphate showed no respiration inhibition of activated sludge at a concentration of 10000 mg/L. The EC50 is higher than 10000 mg/L.

The effect value related to nominal concentration, since no analytical monitoring was performed.