Fatty acids, C18-36, esters with ethylene glycol

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:

15 January 2018 to 19 January 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

Deviations:

yes

Remarks:

no analytics were performed because it was not possible to develop a suitable analytical method

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

no

Remarks:

no analytical method is available

Vehicle:

no

Details on test solutions:

The 100 mg/L WAF was prepared by adding a nominal 0.2 g of the substance (actual weight: 0.19994 g) to 2000 mL of test media. The control was treated the same without the addition of test substance.
The solutions were stirred for 24 hours and left to settle for approximately 1 hour 20 mins.
As precipitate and particles were observed, the sample was taken from the water soluble middle portion of the vessel

Test organisms (species):

Raphidocelis subcapitata (previous names: Pseudokirchneriella subcapitata, Selenastrum capricornutum)

Details on test organisms:

TEST ORGANISM
- Common name: Pseudokirchneriella subcapitata
- Strain: CCAP 278/4
- Source (laboratory): in house culture
- Age of inoculum (at test initiation): 4 days
- Method of cultivation: axenic, similar to test conditions

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Test temperature:

21.5-22.1 °C

pH:

7.29-7.78

Nominal and measured concentrations:

nominal: 0 and 100mg/L (WAF)

Details on test conditions:

TEST SYSTEM
- Test vessel: glass conical flasks of 250 mL nominal capacity with 100 mL test solution
- Type: closed with foam bungs
- Aeration: no
- Initial cells density: 0.5E4 cells/mL (nominal); 0.521E4 cells/mL (measured and taken as starting point)
- Control end cells density: 29.6E4 cells/mL
- No. of vessels per concentration (replicates): 6
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes AAP-medium according to the guideline

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: continuous
- Light intensity and quality: 6233 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: coulter counter
- Chlorophyll measurement: not included
- Other: cells of all concentrations (single replicate) were examined microscopically at the end of the test

Reference substance (positive control):

no

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

cell number

Duration:

72 h

Dose descriptor:

NOELR

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

cell number

Duration:

72 h

Dose descriptor:

EL50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

growth rate

Duration:

72 h

Dose descriptor:

NOELR

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Remarks:

WAF

Basis for effect:

growth rate

Details on results:

The microscopic observations, made at the end of the test, showed that compared to the control the algal cells sampled from the nominal 100 mg/L test concentration appeared normal.

Algal cell particle density (measured not corrected for the initial concentration of 0.521E04 cells/mL)

Nominal loading concentration (mg/L)	Replicate	Algal cell particle density (10^4cells/mL)
		24 hours	48 hours	72 hours
Culture medium control	A	1.65	4.95	25.2
	B	2.48	6.71	31.4
	C	2.09	5.04	27.1
	D	2.43	7.23	34.1
	E	2.53	6.36	30.1
	F	2.19	6.05	29.7
	Mean	2.23	6.06	29.6
100	A	1.87	6.30	33.5
	B	2.07	6.30	27.1
	C	1.95	5.28	27.2
	D	2.17	4.32	25.6
	E	1.64	4.31	23.8
	F	2.10	4.85	28.0
	Mean	1.97	5.23	27.5

Inoculum (Day 0) cell density = 0.521 x 10⁴cells/mL.

Algal cell particle density values are quoted to 3 significant figures.

Mean growth rates over the test period

Nominal loading concentration of (mg/L)	Mean growth rate/day (0-72 hours)	Mean growth rate/day 95% Cl	Percentage of control (%)
Culture medium control	1.35	1.31-1.38	-
100	1.32	1.28-1.36	98

All biological measurements are quoted to 3 significant figures and percentages to the nearest integer.

Mean yields over the test period (corrected for the initial concentration of 0.521E04 cells/mL)

Nominal loading concentration of (mg/L)	Mean yield (0-72 hours) (10^4cells/ml)	Mean yield 95% Cl (10^4cells/ml)	Percentage of control (%)
Culture medium control	29.1	25.8-32.4	-
100	27.0	23.6-30.5	93

Mean yield values are quoted to 3 significant figures and percentages to the nearest integer.

Validity criteria fulfilled:

yes

Conclusions:

The EL50 for yield and growth rate is > 100 mg/L; the NOELR yield and growth rate is 100 mg/L

Executive summary:

In a test according to OECD 201 Green algae (Pseudokirchneriella subcapitata) were exposed to the substance as a Water Accommodated Fraction (WAF) with a loading rate of 0 and 100 mg/L during 72 hours. No confirmatory analysis of the test solutions was performed due to lack of an analytical method. No effects on yield and growth rate were observed. All algae appeared normal at microscopic evaluation at the end of the test. The EL50 is >100 mg/L and the NOELR is 100 mg/L for growth rate and yield.

Description of key information

In a test according to OECD 201 Green algae (Pseudokirchneriella subcapitata) were exposed to the substance as a Water Accommodated Fraction (WAF) with a loading rate of 0 and 100 mg/L during 72 hours. No confirmatory analysis of the test solutions was performed due to lack of an analytical method. No effects on yield and growth rate were observed. All algae appeared normal at microscopic evaluation at the end of the test. The EL50 is >100 mg/L and the NOELR is 100 mg/L for growth rate and yield.

Key value for chemical safety assessment

EC50 for freshwater algae:

100 mg/L

EC10 or NOEC for freshwater algae:

100 mg/L