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Ecotoxicological information

Toxicity to microorganisms

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Endpoint:
activated sludge respiration inhibition testing
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
Refer to the Category Approach Justification document provided in IUCLID6 Section 13.
Reason / purpose:
read-across source
Analytical monitoring:
no
Vehicle:
no
Test organisms (species):
activated sludge
Details on inoculum:
- Initial biomass concentration: 1.5 g/L suspended solids- Source: Rungsted municipal treatment plant, Denmark, treating almost exclusively domestic sewage
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
3 h
Reference substance (positive control):
not specified
Duration:
3 h
Dose descriptor:
EC50
Effect conc.:
135 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Duration:
30 min
Dose descriptor:
EC50
Effect conc.:
188 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
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: Acceptable, well documented publication which meets basic scientific principles
Justification for type of information:
Refer to the Category Approach Justification document provided in IUCLID6 Section 13.
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test
Version / remarks:
respiration test according to OECD 1976
Deviations:
no
Principles of method if other than guideline:
The respiration inhibition of the test substance to a sludge concentration of 1.5 g/L suspended solids is recorded after 3 hours.
GLP compliance:
no
Analytical monitoring:
no
Vehicle:
no
Test organisms (species):
activated sludge
Details on inoculum:
- Initial biomass concentration: 1.5 g/L suspended solids- Source: Rungsted municipal treatment plant, Denmark, treating almost exclusively domestic sewage
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
3 h
Reference substance (positive control):
not specified
Duration:
3 h
Dose descriptor:
EC50
Effect conc.:
135 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate
Duration:
30 min
Dose descriptor:
EC50
Effect conc.:
188 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
inhibition of total respiration
Remarks:
respiration rate

Description of key information

3h EC50 (activated sludge, domestic) = 135 mg/L (respiration inhibition test, similar to OECD 209)

Key value for chemical safety assessment

EC50 for microorganisms:
135 mg/L

Additional information

Since no reliable studies on toxic effects of C9-12AS Na to microorganisms are available, in accordance to Regulation (EC) No. 1907/2006 Annex XI, 1.5, a read-across to other structurally related category members was conducted. The key study was performed with C12AS Na (CAS 151-21-3) using activated sludge from a municipal sewage treatment plant (Dutka 1983). Since the toxicity of alkyl sulfates is dependent on the carbon chain length, it is expected that the toxic effects of the C12 homologue will be representative for C9-12AS Na. The non-GLP test was performed with C12AS Na according to a guideline similar to OECD 209. The EC50 values of 188 and 135 mg/L (nominal concentrations) were obtained for the endpoint respiration inhibition after 30 minutes and 3 hours of exposure, respectively. The 3-hour EC50 value of 135 mg/L was used for the PNEC STP derivation for C10-12AS Na (CAS 85049-86-1).

Due to structural and property similarities with the tested category members it can be concluded that the above results apply also to C9-12AS Na.