Registration Dossier

Administrative data

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:
other: Not a guideline study, but well reported and conducted study

Data source

Reference
Reference Type:
publication
Title:
Effect of arsenic and mercury speciation on inhibition of respiration rate in activated sludge systems.
Author:
Stasinakis AS, Thomaidis NS, Apostolos GS, Themistokles LD
Year:
2003
Bibliographic source:
Environmental Science and Pollution Research International 10, 177-182

Materials and methods

Test guidelineopen allclose all
Qualifier:
no guideline followed
Qualifier:
equivalent or similar to
Guideline:
other: APHA (1989): Standard methods for the examination of water and wastewater, 17th ed. American Public Health Association
Principles of method if other than guideline:
Assessment of arsenic toxicity to respiration rate of activated heterotrophic sludge microorganisms
GLP compliance:
not specified

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
analytical grade (99%) from Aldrich

Test organisms

Test organisms (species):
activated sludge, domestic

Study design

Test type:
static
Water media type:
freshwater
Total exposure duration:
10 d

Results and discussion

Effect concentrationsopen allclose all
Duration:
2.5 d
Dose descriptor:
EC50
Effect conc.:
6.1 mg/L
Nominal / measured:
nominal
Conc. based on:
element
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Remarks on result:
other: lowest reported EC50 for As (III)
Duration:
5 d
Dose descriptor:
EC50
Effect conc.:
7.3 mg/L
Nominal / measured:
nominal
Conc. based on:
element
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Remarks on result:
other: for As (III)
Duration:
10 d
Dose descriptor:
EC50
Effect conc.:
10.6 mg/L
Nominal / measured:
nominal
Conc. based on:
element
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Remarks on result:
other: for As (III)

Applicant's summary and conclusion

Conclusions:
The lowest reported EC50 for respiration inhibition is 6.1 mg As/L.