Reaction mass of 5,12-dihydroquino[2,3-b]acridine-7,14-dione and aluminium tris(5,7,12,14-tetrahydro-7,14-dioxoquino[2,3-b]acridine-2-sulphonate) and dialuminium tris(5,7,12,14-tetrahydro-7,14-dioxoquino[2,3-b]acridine-2,9-disulphonate)

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

02 Nov 2016 to 23 Jan 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test (Carbon and Ammonium Oxidation))

Version / remarks:

2010

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Reaction mass of 5,12-dihydroquino[2,3-b]acridine-7,14-dione and aluminium tris(5,7,12,14-tetrahydro-7,14-dioxoquino[2,3-b]acridine-2-sulphonate) and dialuminium tris(5,7,12,14-tetrahydro-7,14-dioxoquino[2,3-b]acridine-2,9-disulphonate)

EC Number:

909-092-5

Molecular formula:

Unspecified

IUPAC Name:

Reaction mass of 5,12-dihydroquino[2,3-b]acridine-7,14-dione and aluminium tris(5,7,12,14-tetrahydro-7,14-dioxoquino[2,3-b]acridine-2-sulphonate) and dialuminium tris(5,7,12,14-tetrahydro-7,14-dioxoquino[2,3-b]acridine-2,9-disulphonate)

Test material form:

solid

Specific details on test material used for the study:

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
Ambient at room temperature

Sampling and analysis

Analytical monitoring:

no

Test solutions

Vehicle:

no

Details on test solutions:

Direct addition by initial weight into the test flasks. The test substance was weighed in the required amounts for the test concentrations directly to the test vessels.

Test organisms

Test organisms (species):

activated sludge, domestic

Details on inoculum:

- Age: 1 day
- Origin: Aeration tank of a wastewater treatment plant of Mannheim, Germany
- Collection of the test system: 02 Nov 2016
- Arrival in the test facility: 02 Nov 2016
- Pretreatment: After arrival of the activated sludge suspension in the test facility the suspension was sieved with a fine woven mesh (mesh size about 1 mm). This suspension was pre-aerated over night at room temperature. At the next day the sludge suspension was washed once with drinking water and the suspension was adjusted to 3 g/L dw.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test conditions

Test temperature:

20.1 - 21.3 °C

pH:

7.4 - 7.5

Nominal and measured concentrations:

- Nominal concentrations: 0 (control), 62.5, 125, 250, 500 and 1000 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Glas-beakers (nominal volume 1L)
- Test volume: 500 mL
- Aeration: Yes, oxygen concentration during aeration was > 2 mg/L
- No. of vessels per concentration: 3
- No. of vessels per control: 6
- No. of vessels per reference substance concentration: 2
- Sludge concentration (weight of dry solids per volume): 1.5 g/L dw

PREPARATION OF THE TEST
The test substance was added in the required amounts according to the test concentrations directly to the test vessels with 234 mL deionised water. Aliquots of the reference substance stock solution were dosed to the test vessels and made up with deionised water to a volume of 234 mL. 16 mL synthetic medium were dosed to each test vessel with test substance and reference substance afterwards. To prepare the blank control assays 234 mL of deionised water and 16 mL synthetic medium were mixed. The pH-values in all test vessels were checked. An adjustment was not necessary. After addition of 250 mL of inoculum suspension (3 g/L DW) the incubation was started by aeration of the test vessels with pressured air. The vessels for the blank control assays were prepared to the same procedure without addition of test- or reference substance.

TEST MEDIUM / WATER PARAMETERS
- Synthetic medium: 16 mL/test vessel of 100-fold concentrated OECD medium

OTHER TEST CONDITIONS
- Adjustment of pH: Yes, the pH value of the stock solution was measured and adjusted to 7.2 with 1 M sodium hydroxide solution.
- Measurement of temperature: The temperature was measured for seven times in a separate vessel filled with aerated deionized water during incubation phase.

EFFECT PARAMETERS MEASURED: The total oxygen consumption of was measured after 3 hours of incubation for a duration of 8 - 10 minutes.

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:

No inhibition of oxygen consumption was observed at any of the tested concentrations. Consequently, no monotone concentration response exists.

Results with reference substance (positive control):

The 3-h EC50 value of the reference substance was determined to be 11.1 mg/L.

Reported statistics and error estimates:

The consumption rates were used for the determination of the ECx for the reference substance by the probit method based on Finney with the software TOXRAT Professional 2.10.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

See 'Any other information on materials and methods incl. tables'.

Conclusions:

The inhibition of the degradation activity of activated sludge is not anticipated when introduced to biological treatment plants in appropriate low concentrations.