Vanadium trichloride oxide

Toxicity to microorganisms

Administrative data

Endpoint:

activated sludge respiration inhibition testing

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

February 2013

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP study following the current guideline, but quoted with reliability 2 due to the read across.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2013

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Divanadium pentaoxide

EC Number:

215-239-8

EC Name:

Divanadium pentaoxide

Cas Number:

1314-62-1

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

Details on test material:

Description: orange colored powder
Purity: 99.7%
Expiry date: 24 December 2013
Storage conditions: room temperature in the dark

Sampling and analysis

Analytical monitoring:

not required

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
Method: the test item was dispersed in approximately 200 mL of deionized reverse osmosis water and subjected to ultrasonication for approximately 15 minutes followed by magnetic stirring for 24 hours in order to maximize the dissolved test item concentration.

Test organisms

Test organisms (species):

activated sludge of a predominantly domestic sewage

Details on inoculum:

A mixed population of activated sewage sludge micro-organisms was obtained from the aeration stage of the Severn Trent Water Plc sewage treatment plant at Loughborough, Leicestershire, UK which treats predominantly domestic sewage.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

3 h

Test conditions

Hardness:

no data

Test temperature:

20°C +/- 2°C

pH:

7.3 to 7.7 at the beginning of the test
7.4 to 8.2 after 3 hours

Dissolved oxygen:

2.9 to 5.7 mg O2/ L

Nominal and measured concentrations:

10, 40, 160, 640 and 2500 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 500 mL conical flask
- Aeration: The mixture was aerated with clean, oil-free compressed air via narrow bore glass tubes at a rate of approximately 0.5 – 1 liter per minute.
- No. of vessels per concentration (replicates): 3 replicates
- Biomass loading rate: suspended solids concentration: 3 g/L

TEST MEDIUM / WATER PARAMETERS: deionized reverse osmosis water containing less than 1 mg/L dissolved organic carbon

EFFECT PARAMETERS MEASURED : oxygen concentration rate

TEST CONCENTRATIONS
- Range finding study: 10, 100 and 1000 mg/L, gave toxicity from 10 mg/L
- Test concentrations: chosen to obtain EC10 and EC50: 10, 40, 160, 640 and 2500 mg/L

Reference substance (positive control):

yes

Remarks:

3,5- dichlorophenol

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

3 h

Dose descriptor:

EC10

Effect conc.:

14 mg/L

Nominal / measured:

nominal

Conc. based on:

element

Remarks:

vanadium

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Effect concentrations 2

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

2 719 mg/L

Nominal / measured:

nominal

Conc. based on:

element

Remarks:

vanadium

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Results with reference substance (positive control):

EC10, 3 hours: 0.24 mg/L
EC50, 3h : 6.3 mg/L

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

The coefficient of variation of oxygen uptake in the control vessels was 7.0% and the specific respiration rate of the controls was 27.67 mg oxygen per gram dry weight of sludge per hour.

Executive summary:

Following a preliminary range-finding test, activated sewage sludge was exposed to aqueous dispersions of V2O5 at concentrations 10, 40, 160, 640 and 2500 mg/L (three replicates of each) for a period of 3 hours at a temperature of 20 ± 2 °C with the addition of a synthetic sewage as a respiratory substrate.

When expressed as vanadium, the test item concentrations were 5.6, 22.4, 89.6, 358.4 and 1400 mg V/L.

The effect of the test item on the respiration of activated sewage sludge gave an EC 10 value of 25 mg/L and an EC 50 value of 4865 mg/L after 3 hours exposure expressed as test item content.

When expressed as vanadium, the effect of the test item on the respiration of activated sewage sludge gave an EC 10 value of 14 mg V/L and an EC 50 value of 2719 mg V/L after 3 hours exposure.