Dihydrogen bis[monoperoxyphthalato(2-)-O1,OO1]magnesate(2-)

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

2002

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 (Carbon and Ammonium Oxidation))

Version / remarks:

1984

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Fresenius

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

activated sludge

Details on inoculum:

- Name and location of sewage treatment plant where inoculum was collected: Municipal sewage treatment plant of the city of Taunusstein-Bleidenstadt, Germany, Effluent of the aeration tank.
- Method of cultivation: Not applicable
- Preparation of inoculum for exposure: Activated sludge was preincubated for one or two days at 20 ± 2 °C with 50 mL of synthetic slugde being added daily to each litre of activated sludge. Sludge was aerated until use.
- Pretreatment: Culturing under aerobic conditions prior to the experiments at test temperature.
- Initial biomass concentration: 3.6 – 4.4 g dry substance/L

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test temperature:

17.1 - 17.8 °C (main test)

pH:

8.25 - 8.60 (main test)

Nominal and measured concentrations:

Control, 100, 200, 400, 800 and 1000 mg/L (nominal)

Details on test conditions:

TEST SYSTEM
- Test vessel: Glassbottles (250 mL)
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 2
- Biomass loading rate: 100 mL of the inoculum
1.6 g dry substance /L
(= 4 g/L • 100 mL/250 mL)



EFFECT PARAMETERS MEASURED :
Respiration inhibition, Oxygen measurement, Sampling after 3 hours contact time with test substance

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol

Duration:

3 h

Dose descriptor:

EC0

Effect conc.:

71 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Key result

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

280 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Duration:

3 h

Dose descriptor:

EC100

Effect conc.:

1 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Duration:

3 h

Dose descriptor:

other: EC20

Effect conc.:

123 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks on result:

other: recalculated by applicant

Duration:

3 h

Dose descriptor:

other: EC80

Effect conc.:

635 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks on result:

other: recalculated by applicant

Details on results:

- Blank controls oxygen uptake rate: 37.2 mg/L•h and 37.8 mg/L•h

Results with reference substance (positive control):

5, 15 and 30 mg/L
EC50 (3 h) = approx. 15 mg/L

Reported statistics and error estimates:

Effect values were calculated using regression analyses of the log concentration/ % inhibition curve

 

Preliminary test	Yes
Concentration	1, 10, 100 and 1000 mg/L
Effect data	Not calculated: Inhibition at 1000 mg/L: 95.2%, at 100 mg/L: 14.3%, at 10 mg/L: 9.5% and at 1 mg/L: 7.9%

 

Validity criteria fulfilled:

yes

Conclusions:

The acute toxicity of MMPP towards activated sludge microorganisms is low.

Executive summary:

The acute toxicity of MMPP towards bacteria was tested according to the OECD guideline 209. Sludge was obtained from the municipal sewage treatment plant of the city of,, and incubated for 3 hours with the test or reference compound. Oxygen consumption was measured after 3 hours.

The numerical results are given below (data were recalculated by the applicant to give EC₂₀ and EC₈₀ values). Additionally, the EC₁₀ value is 93 mg/L; EC₀ was given to be 71 mg/L.

Analytical monitoring of test concentration is not required for this test system. However,volatility of MMPP from aqueous solutions can be neglected and therefore this property has no influence on the result.

The test is considered as valid as the validity criteria given in OECD 209 are 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).

A dose-response-relationship with adequate accuracy was obtained.

Key value for chemical safety assessment

EC50 for microorganisms:

280 mg/L