Aluminum magnesium vanadium oxide

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:

16 Nov - 06 Dec 2012

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

Version / remarks:

adopted 22 Jul 2010

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test)

Version / remarks:

adopted 30 May 2008

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Rheinland-Pfalz, Landesamt für Umwelt, Wasserwirtschaft und Gewerbeaufsicht, Mainz, Germany

Analytical monitoring:

no

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
The test item was directly added to the test vessels.

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

- Source: The sludge was taken from the activation basin of the ESN (Stadtentsorgung Neustadt) sewage treatment plant D-67435 NW-Lachen-Speyerdorf.
- Pretreatment: Upon arrival in the test facility, the sludge was filtrated, washed with tap water and re-suspended in tap water. The activated sludge was aerated until usage in the test and fed daily with 50 ml/L synthetic sewage feed.
- Initial biomass concentration (first experiment): 2.90 g suspended solids/L (1.45 g suspended solids/L in the test)
- Initial biomass concentration (second experiment): 3.00 g suspended solids/L (1.50 g suspended solids/L in the test)

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Hardness:

1.08 mmol/L (Analysis of drinking water, Sep 2012)

Test temperature:

18.9 – 20.0 °C (first experiment)
18.0 – 18.8 °C (second experiment)

Nominal and measured concentrations:

control, 1, 10, 100 and 1000 mg/L (nominal) (first experiment)
control, 320 and 1000 mg/L (nominal) (second experiment)

Details on test conditions:

TEST SYSTEM
- Test vessel:
- Material, size, headspace, fill volume: Glass beakers
- Aeration: purified air, using Pasteur pipettes, flow approx. 0.75 L/min
- No. of vessels per concentration (replicates, first experiment): 5 for 1000 mg/L; for other concentrations 1 replicate
- No. of vessels per concentration (replicates, second experiment): 5 for both 1000 and 320 mg/L
- No. of vessels per control (replicates, both experiments): 6
- Biomass loading rate first experimenmt): 1.45 g suspended solids/L
- Biomass loading rate first experimenmt): 1.50 g suspended solids/L

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: tap water
- Total organic carbon: 0.4 mg/L
- Metals: Al 0.006 mg/L; Cu 0.002 mg/L; others < LOQ
- Pesticides: < LOD
- Chloride: 14.0 mg/L
- Conductivity: 330 µS/cm

EFFECT PARAMETERS MEASURED (with observation intervals if applicable): O2 consumption, measured at the end of exposure

Reference substance (positive control):

yes

Remarks:

3.5-Dichlorophenol

Duration:

3 h

Dose descriptor:

NOEC

Effect conc.:

320 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

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

Remarks:

respiration rate

Results with reference substance (positive control):

- Results with reference substance valid? yes
- Relevant effect levels: 16 Nov 2012: 3h EC50 = 6.6 mg/L; 06 Dec 2012: 3h EC50 = 7.8 mg/L

Reported statistics and error estimates:

For the treatments with the test item concentrations 1000 and 320 mg/L (experiment 2 only), it was tested whether the differences between treatment and control were significant. For this determination, the values of the O2 consumption were used. In order to select a suitable test for significance, it was checked whether equality of variance was given. If equality of variance is given, the t-test is used; else, the WEIR test is used. The difference between treatment 1000 mg/L and the control can be considered as significant as the calculated t-value lay above the significance level and O2 consumption in the treatment was higher than in the control. Therefore, the NOEC is stated as 320 mg/L. The highest treatment of nominal 1000 mg/L showed inhibition values below 10 %, therefore EC10 and EC50 lies above 1000 mg/L.

Table 1. O2 -consumption, inhibition; first experiment

Vessel No.	Content	Concentration in mg/L	O2 consumption in mg/(L*min.)	O2 consumption in mg/(L*h)	Inhibition in %	pH
1	Control	0	0.7928	47.566	0	7.7
2	Control	0	0.7550	45.300	0	7.7
3	Positive Control	5	0.4845	29.069	38.7	7.8
4	Positive Control	10	0.2772	16.631	64.9	7.8
5	Positive Control	20	0.1280	7.679	83.8	7.8
6	Positive Control	40	0.0638	3.826	91.9	7.8
7	Control	0	0.8041	48.248	0	7.6
8	Control	0	0.7685	46.112	0	7.7
9-16	*	*	*	*	*	*
17	Test Item	1003.6	0.7188	43.130	9.0	8.2
18	Test Item	1001.8	0.7437	44.624	5.8	8.2
19	Test Item	1000.0	0.7522	45.132	4.8	8.1
20	Test Item	999.8	0.7395	44.368	6.4	8.2
21	Test Item	1002.2	0.7388	44.330	6.5	8.2
22	Test Item	100	0.7886	47.313	0.2	7.7
23	Test Item	11	0.8049	48.296	-1.9	7.6
24	Test Item	1	0.7849	47.094	0.6	7.6
25	Control	0	0.8184	49.106	0	7.5
26	Control	0	0.8001	48.007	0	7.6

*other test items were measured in vessels 9 – 16

Table 4. O2 -consumption, inhibition; second experiment

Vessel No.	Content	Concentration in mg/L	O2 consumption in mg/(L*min.)	O2 consumption in mg/(L*h)	Inhibition in %	pH
1	Control	0	0.5673	34.039	0	7.8
2	Control	0	0.5513	33.076	0	7.8
3	Positive Control	5	0.3820	22.921	33.6	7.9
4	Positive Control	10	0.2244	13.466	61.0	7.9
5	Positive Control	20	0.1159	6.956	79.9	8.0
6	Positive Control	40	0.0674	4.042	88.3	8.0
7	Control	0	0.5858	35.148	0	7.8
8	Control	0	0.5727	34.364	0	7.8
9	Test Item	1000.2	0.5311	31.864	7.7	8.4
10	Test Item	1001.2	0.5270	31.621	8.4	8.4
11	Test Item	1000.0	0.5384	32.303	6.5	8.4
12	Test Item	1001.0	0.5343	32.061	7.2	8.4
13	Test Item	1001.6	0.5336	32.019	7.3	8.4
14	Test Item	320.8	0.5488	32.925	4.7	8.0
15	Test Item	320.0	0.5540	33.238	3.8	8.0
16	Test Item	321.0	0.5630	33.778	2.2	7.9
17	Test Item	321.6	0.5673	34.038	1.4	8.0
18	Test Item	320.6	0.5710	34.257	0.8	8.0
19	Control	0	0.5808	34.846	0	7.8
20	Control	0	0.5957	35.741	0	7.8

 

Description of key information

EC50 (3h) > 1000 mg/L (nominal) (OECD 209, activated sludge)

Additional information

The determination of the inhibition of the respiration of activated sludge exposed to aluminium magnesium vanadium oxide was conducted according to OECD 209 and GLP (2013). Two valid experiments were performed. In the first experiment, the test item was exposed to four concentrations (1, 10, 100 and 1000 mg/L). Duration of the test was three hours. Activated sludge was used as inoculum. It was taken from a domestic sewage treatment plant and washed before usage. For the determination of the NOEC, a second experiment was performed. Because of low inhibition at the highest treatment and low solubility in the test medium, no full test was conducted. The second experiment was performed in the same way like the first, but using two concentrations, namely 1000 and 320 mg/L (nominal). The 3h NOEC is 320 mg/L and EC10 and EC50 are > 1000 mg/L.