Registration Dossier

Diss Factsheets

Ecotoxicological information

Toxicity to microorganisms

Currently viewing:

Administrative data

Link to relevant study record(s)

Referenceopen allclose all

Endpoint:
activated sludge respiration inhibition testing
Type of information:
experimental study
Adequacy of study:
key study
Study period:
4 Jul 1997
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
EU Method C.11 (Biodegradation: Activated Sludge Respiration Inhibition Test)
Version / remarks:
reported as EG-guideline 88/302/EG (30.05.1988)
GLP compliance:
yes
Analytical monitoring:
no
Vehicle:
no
Details on test solutions:
PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Stock solution (5000,3 mg test substance in VE water) ad 200 mL (VE-Water) plus 200 µL Baysilone (foam killer)
Test organisms (species):
activated sludge of a predominantly domestic sewage
Details on inoculum:
- Source: Municipal sewage treatment plant "Marl-West"
- Preparation of inoculum for exposure: sludge was sampled, allowed to settle, washed with 2 L tap water, aerated for 30 min and stirred; 200 mL synthetic effluenct were added to the cleaned sludge and tap water added ad 4 L
- Pretreatment: On test day, the sludge was allowed to settle and was washed twice with 2 L tap water
- Initial biomass concentration: 3.82 g dry substance/L
Test type:
static
Water media type:
freshwater
Limit test:
no
Total exposure duration:
3 h
Post exposure observation period:
not relevant
Hardness:
no data
Test temperature:
20 ± 2 °C
pH:
8.0-8.4
Dissolved oxygen:
>2.5 mg/L
Salinity:
not relevant
Nominal and measured concentrations:
Nominal: 0, 260, 390, 578.5, 864.5 and 1300 mg/L
Details on test conditions:
TEST SYSTEM
- Test vessel: 500 mL beaker
- Renewal rate of test solution (frequency/flow rate): none
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 2
- No. of vessels per reference control (replicates): 3


- Culture medium different from test medium: no


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : oxygen consumption rate (manometric)


TEST CONCENTRATIONS
- Spacing factor for test concentrations: 1.5
Reference substance (positive control):
yes
Remarks:
Dichlorophenol
Duration:
3 h
Dose descriptor:
EC50
Effect conc.:
680 mg/L
Nominal / measured:
nominal
Conc. based on:
act. ingr.
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: EC50 between 5 and 30 mg/L (test result: 8.1 mg/L)
Reported statistics and error estimates:
Excel, program auswert.msk, probit and logarithm of concentration calculated, results from linear section of regression curve
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 for cross-reference:
read-across source
Duration:
3 h
Dose descriptor:
EC50
Effect conc.:
680 mg/L
Nominal / measured:
nominal
Conc. based on:
act. ingr.
Basis for effect:
growth inhibition
Remarks on result:
other: read-across from CAS 68955-19-1

Description of key information

3h EC50 (activated sludge, domestic) = 680 mg/L (respiration inhibition test, EU method C.11)

Key value for chemical safety assessment

EC50 for microorganisms:
680 mg/L

Additional information

Since no reliable toxicity tests with microorganisms are available for C14-16AS Na (CAS 91648-54-3), in accordance to Regulation (EC) No. 1907/2006 Annex XI, 1.5 a read-across to another structurally related category member was conducted. Read-across data from C12-18AS Na (68955-19-1) were used.

In the GLP-study with C12-18AS Na (CAS 68955-19-1) conducted according to the EU method C.11, an EC50 of 680 mg a.i./L is reported for the respiration rate after 3 h of exposure.

Due to structure and property similarities with the tested category member it can be concluded that the above result applies also to C14-16AS Na (CAS 91648-54-3). The 3h EC50 value for microorganisms is considered to be 680 mg/L. This value was used for the PNEC STP derivation.