Registration Dossier

Ecotoxicological information

Toxicity to microorganisms

Currently viewing:

Administrative data

Link to relevant study record(s)

Reference
Endpoint:
activated sludge respiration inhibition testing
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Justification for type of information:
Peer reviewed publication assessing effects of heavy metals on sewage respiration
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test (Carbon and Ammonium Oxidation))
Principles of method if other than guideline:
Oxygen consumption measured as well as microscopic observations for activity of micro-organisms
Experiment was based on slowly increasing concentration of vanadium until reduction in oxygen consumption was noted. Total period of testing was over 110 days.
GLP compliance:
no
Specific details on test material used for the study:
Noted to be hygroscopic and difficult to handle as solid.
Analytical monitoring:
yes
Details on sampling:
Verification of starting concentrations
Vehicle:
no
Test organisms (species):
activated sludge
Details on inoculum:
Source not specified in terms of domestic or industrial
Test type:
flow-through
Water media type:
freshwater
Limit test:
no
Total exposure duration:
50 d
Remarks on exposure duration:
Experiment was based on slowly increasing concentration of vanadium until reduction in oxygen consumption was noted. Exposure not started until day 60 and ended day 110.
Nominal and measured concentrations:
Maximum addition rate of 200 mg/l vanadium
Reference substance (positive control):
no
Duration:
50 d
Dose descriptor:
EC10
Effect conc.:
ca. 20 mg/L
Nominal / measured:
meas. (initial)
Conc. based on:
element
Remarks:
Vanadium
Basis for effect:
inhibition of total respiration
Remarks on result:
not determinable
Duration:
50 d
Dose descriptor:
EC50
Effect conc.:
ca. 100 mg/L
Nominal / measured:
meas. (initial)
Conc. based on:
element
Remarks:
Vanadium
Basis for effect:
inhibition of total respiration
Key result
Duration:
50 d
Dose descriptor:
EC50
Effect conc.:
ca. 340 mg/L
Nominal / measured:
estimated
Conc. based on:
test mat.
Remarks:
Registered substance
Basis for effect:
inhibition of total respiration
Details on results:
The report does not indicate the time duration between sequential increases in concentration and the reduction in inhibiton and the 'duration' of 50 days indicated in the results table relates to the period of exposure to vanadium.

Although there was a significant reduction of up to 50% in respiration rate at 100 mg/l vanadium, additional concentrations over the following 20 days or so with concentration ramping up to 200 mg/l failed to reduce the oxygen consumption further and there was an indication of adaption with the respiration actually increasing over the longer period.

Conclusions:
Although the cited research uses unconventional methods, it demonstrates that vanadium has a significant impact on sludge respiration from about 20 mg/l and a 50% reduction was seen at ca 100 mg/l vanadium (estimated ca 340 mg/l using the nominal molecular weight of 173 for the registed substance)

Description of key information

Although the cited research uses unconventional methods, it demonstrates that vanadium has a significant impact on sludge respiration from about 20 mg/l and a 50% reduction was seen at ca 100 mg/l vanadium (estimated ca 340 mg/l using the nominal molecular weight of 173 for the registed substance)

Key value for chemical safety assessment

EC50 for microorganisms:
340 mg/L
EC10 or NOEC for microorganisms:
68 mg/L

Additional information