Sulfuric acid, mono-C8-18-alkyl esters, magnesium salts, compds. with triethanolamine

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:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

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

Reference 2

Endpoint:

activated sludge respiration inhibition testing

Type of information:

experimental study

Adequacy of study:

key study

Study period:

04. Jul 1997

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

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 a-WAS/L (= active substance)

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.

Remarks:

a-WAS

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 3

Endpoint:

toxicity to microorganisms

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Comparable to national guideline study with acceptable restrictions.

Qualifier:

according to guideline

Guideline:

other: cell multiplication inhibition test acc. to Bringmann and Kühn (1977)

GLP compliance:

not specified

Analytical monitoring:

not specified

Vehicle:

not specified

Test organisms (species):

Pseudomonas putida

Test type:

not specified

Water media type:

freshwater

Total exposure duration:

18 h

Duration:

18 h

Dose descriptor:

NOEC

Effect conc.:

550 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth inhibition

Reference 4

Endpoint:

toxicity to microorganisms

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

12 Nov - 15 Nov 1991

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP study performed according to national guideline.

Qualifier:

according to guideline

Guideline:

DIN 38412-8 (Pseudomonas Zellvermehrungshemmtest)

GLP compliance:

yes

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

Pseudomonas putida

Details on inoculum:

- Laboratory culture: Stamm Berlin 33/2 (DSM 50026)

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

16 h

Post exposure observation period:

not relevant

Test temperature:

21 °C

pH:

6.6 - 6.8

Nominal and measured concentrations:

nominal: 0, 1000, 3000 and 10000 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: Clim-o-shake at 100 rpm

EFFECT PARAMETERS MEASURED: growth inhibition, measured photometrically at 436 nm (Zeiss filterphotometer PL4)

Reference substance (positive control):

no

Duration:

16 h

Dose descriptor:

EC0

Effect conc.:

409 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth inhibition

Duration:

16 h

Dose descriptor:

EC10

Effect conc.:

1 083.85 mg/L

Nominal / measured:

nominal

Conc. based on:

act. ingr.

Basis for effect:

growth inhibition

0.58% inhibition at 1000 mg prod./L

15.3% inhibition at 3000 mg prod./L

60.63% inhibition at 10000 mg prod./L

Description of key information

EC50(3h) = 135 mg/L (nominal) for respiration inhibition of activated sludge (EU Method C.11, read across CAS 151-21-3)

 

Key value for chemical safety assessment

EC50 for microorganisms:

135 mg/L

Additional information

Since no reliable studies on toxic effects of C8-18AS Mg & TEA (CAS 85586-38-5) to microorganisms are available, in accordance to Regulation (EC) No. 1907/2006 Annex XI, 1.5, a read-across to other structurally related alkyl sulfates was conducted. A key study was performed with C12AS Na (CAS 151-21-3) using activated sludge from a municipal sewage treatment plant (Dutka 1983). The test was performed 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. Since the toxicity of alkyl sulfates is dependent on the carbon chain length reaching its maximum at the C14/C15 carbon chain, it is expected that the toxic effects of the C12AS Na are similiar to a worst case scenario for C8-18AS Mg & TEA. The 3-hour EC50 value of 135 mg/L was used for the PNEC STP derivation for C8-18AS Mg & TEA (CAS 85586-38-5).

Moreover, a study on microorganisms was performed with C12-18AS Na (CAS 68955-19-1).  The respiration inhibition test with activated sludge was conducted according to the EU Method C.11 and is GLP compliant. An EC50 of 680 mg a.i./L was reported for the respiration rate after 3 h of exposure. Due to structural and property similarities with the tested category members it can be concluded that the above results apply also to C8-18AS Mg & TEA (CAS 85586-38-5). Additionally, a GLP test according to DIN 38412 part 8 with Pseudomonas putida using C12-14AS TEA (CAS 90583-18-9) is available (Guhl 1992). In this study, the growth inhibition of Pseudomonas putida was recorded after approximately 16 hours of exposure. The 16-h EC10 value was determined to be 1084 mg a.i./L (nominal concentration). Finally, a reliable study with Pseudomonas putida is available for C16-18AS Na (CAS 68955-20-4; Steber 1988). The study followed the procedure of cell multiplication inhibition test according to Bringmann and Kühn (1977). The growth inhibition of Pseudomonas putida was recorded after 18 hours of exposure to the test substance. The 18-hour NOEC value was determined to be 550 mg a.i./L (nominal concentration).