Alcohols, C12-14, ethoxylated, sulfates, sodium salts

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

12 - 15 Jul 1993

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

other: EU-Guideline 92/69 EWG

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

GLP compliance:

yes

Analytical monitoring:

yes

Details on sampling:

- Concentrations: all concentrations
- Sampling method: samples were taken at 0 and 72 h.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: a stock solution was prepared by dissolving the substance in purified water. Concentration of the stock solution : 0.143 g/L

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

TEST ORGANISM
- Strain: 86.81 SAG
- Source (laboratory, culture collection): originally obtained from Institut für Wasser-, Boden- und Lufthygiene, Berlin. In-house culture
- Age of inoculum (at test initiation): 3 days

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test temperature:

24 °C +/- 2 °C

pH:

Test start: 7.9 - 8.1
Test end: 7.2 - 8.8

Nominal and measured concentrations:

nominal concentrations: 0.7, 1.5, 3, 6, 12 and 24 mg/L based on nominal anionic surfactants concentration
Measured concentrations (initial.): 0.93, 1.8, 3.2, 6.3, 13.8 and 24.5 mg/L based on measured anionic surfactants concentration (MBAS)

Details on test conditions:

TEST SYSTEM
- Test vessel:Erlenmeyer flasks
- Material, fill volume: glass
- Aeration: yes
- Initial cells density: 20000 cells/mL
- Control end cells density: 730000 cells/mL
- No. of vessels per concentration (replicates): 5
- No. of vessels per control (replicates): 8


GROWTH MEDIUM
- Standard medium used: yes according to EU-Guideline 92/69/EWG
Composition of medium according to guideline (final concentration of nutrients in the test solution)
Macronutrients
NH4Cl: 15 mg/l
MgCl2.6H2O: 12mg/l
CaCl2.2H2O: 18 mg/l
MgSO4.7H2O: 15 mg/l
KH2PO4: 1.6 mg/l

Fe -EDTA
FeCl3.6H2O: 0.08 mg/l
Na2EDTA.2H2O: 0.1 mg/l

Trace elements
H3BO3: 0,185 mg/l
MnCl2.4H2O: 0,415 mg/l
ZnCl2: 3 x 10-3 mg/l
CoCl2.6H2O: 1.5 x 10-3 mg/l
CuCl2.2H2O: 10-5 mg/l
Na2MoO4.2H2O: 7 x 10-3mg/l
Stock solution 4: NaHCO3
NaHCO3: 50 mg/l


OTHER TEST CONDITIONS
- Sterile test conditions: yes
- Photoperiod: continuous illumination
- Light intensity and quality: approximately 8000 Lux (white)


EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: spectrophotometer (wave length: 685 nm), determined at 0, 24, 48 and 72 h

Reference substance (positive control):

no

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

27.7 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Remarks on result:

other: corresponds to a measured concentration of 27 mg/L based on anionic surfactants concentration (MBAS)

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

4.4 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Remarks on result:

other: corresponds to a measured concentration of 4.3 mg/L based on anionic surfactants concentration (MBAS)

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

0.95 mg/L

Nominal / measured:

meas. (initial)

Conc. based on:

act. ingr.

Basis for effect:

growth rate

Remarks on result:

other: corresponds to a measured concentration of 0.93 mg/L based on anionic surfactants concentration (MBAS)

Details on results:

- Exponential growth in the control (for algal test): yes

Reported statistics and error estimates:

The EC-values were determined by probit transformation of percental growth inhibition values using regression analysis. Based on these values an additional probit analysis according to Cavalli-Sforza were conducted.

Table 1: Results

Concentration [mg/L]	Cell density (x 10^4cells/mL)
	Test duration
	0 h	24 h	48 h	72 h
Control	2	5	18	73
0.93	2	5	19	73
1.8	2	5	17	58
3.2	2	5	16	59
6.3	2	5	16	53
13.8	2	4	12	19
24.5	2	4	13	14

Table 2: Measured concentrations based on methylene blue active substance concentration (MBAS)

Nominal concentration [mg/L]	Measured concentration [mg/L]
	0 h	48 h
stock solution	105	--
control	0.3*	0.12*
0.7	0.93	0.94
1.5	1.75	1.85
3	3.15	3.4
6	6.25	7.1
12	13.8	13
24	24.5	24.8

* concentrations < 0.5 mg/L are not considered

Table 3: Validity criteria for OECD 201.

Criterion from the guideline	Outcome	Validity criterion fulfilled
The biomass in the control cultures should have increased exponentially by a factor of at least 16 within the 72-hour test period.	37	Yes
The mean coefficient of variation for section-by-section specific growth rates (days 0-1, 1-2 and 2-3, for 72-hour tests) in the control cultures must not exceed 35%	29.2	Yes
The coefficient of variation of average specific growth rates during the whole test period in replicate control cultures must not exceed 7% in tests with Pseudokirchneriella subcapitata and Desmodesmus subspicatus. For other less frequently tested species, the value should not exceed 10%.	1.27	Yes

Validity criteria fulfilled:

yes

Remarks:

The validity crietria according to OECD 201 are fulfilled (for details see table 3 under "any information on results")

Description of key information

ErC50 (72 h): 27.7 mg a.i./L (nominal, OECD 201)

NOErC (72 h): 0.95 mg a.i./L (nominal, OECD 201)

Additional information

The available study on the toxicity of Alcohols, C12-14, ethoxylated, sulfates, sodium salts to algae was conducted according to OECD guideline OECD 201 (GLP). As test organism the green algae Scenedesmus subspicatus was used. The test was conducted with standard medium acc. to the guideline and nominal test concentrations of 0.7, 1.5, 3, 6, 12 and 24 mg/L based on nominal anionic surfactants concentration. The test concentrations were analytically verified using the MBAS assay (methylene blue active substances assay). Based on anionic surfactants concentration (MBAS) test concentrations of 0.93, 1.8, 3.2, 6.3, 13.8 and 24.5 mg/L were determined at test start. Based on the growth rate an ErC50 (72 h) of 27.7 mg a.i./L was determined (corresponding to 27.0 mg a.i./L based on measured anionic surfactants concentration (MBAS)).