Sulfuric acid, mono-C14-16 (even numbered)-alkyl esters, sodium salts

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Reference 1

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

Reference 2

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.