Dodecanoic acid, ester with 1,2-propanediol

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

16 Oct - 19 Oct 2018

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2019

Report date:

2019

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes (incl. QA statement)

Remarks:

interministerial group of chemical products (GIPC)

Test material

Test material information

Constituent 1

Reference substance name:

Dodecanoic acid, ester with 1,2-propanediol

EC Number:

253-462-2

EC Name:

Dodecanoic acid, ester with 1,2-propanediol

Cas Number:

37321-62-3

Molecular formula:

C15H30O3 C27H52O4

IUPAC Name:

Dodecanoic acid, ester with 1,2-propanediol

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

- Concentrations: 0.95, 3.05, 9.76, 31.25 and 100 mg/L at 0 and 72 hours.
- Sampling method: Test item solutions and control were sampled and immediately analysed. Diester: 2 mL of sample were pipetted into a 15 mL conical bottom glass tube and 2 mL of ethyl acetate were added. Samples were vortexed and layers were allowed to separate for one minute. 1 mL of the upper layer was pipetted into a GCMS vial. Monoester: 2 mL of sample were pipetted into a 15 mL conical bottom glass tube and 2 mL of hexane were added. Samples were vortexed and centrifuged for 2 min at 1500 rpm. 1 mL of the upper layer was pipetted into a GCMS vial and 50 μL of derivative agent BSTFA + 1 % TMCS were added.

Test solutions

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: Test solutions were prepared individually by water-accommodated fractions (WAF) approach according to OECD monograph No. 23. WAFs were prepared individually. Measured quantities of test item were added directly to test medium and mixed for 24 hours to achieve an equilibrated concentration of dissolved and dispersed or emulsified components in the aqueous phase. The test solutions have not been filtered. The test solutions used were therefore emulsions of the test element.
- Controls: yes (test medium)

Test organisms

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Source (laboratory, culture collection): The algal stock culture was provided by the CCAP (Culture Collection of Algae and Protozoa), reference CCAP 1405/1.
- Method of cultivation: The Pseudokirchneriella subcapitata stock culture was maintained on sloped agar tubes at 4°C and regularly transferred to fresh medium at the laboratory. A pre-culture was prepared from the stock culture and maintained in an exponential growth by successive transfers every 3 to 4 days.

ACCLIMATION
- Culturing media and conditions (same as test or not): OECD medium

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Test conditions

Test temperature:

21.63 - 22.69 °C

pH:

7.66 - 8.81

Nominal and measured concentrations:

nominal (loading rates): 0.95, 3.05, 9.76, 31.25 and 100 mg/L
measured: see below table 2 under "Any other information on results

Details on test conditions:

TEST SYSTEM
- Test vessel: glass Erlenmeyer flasks of 250 mL
- Type (delete if not applicable): closed with air-permeable stoppers made of polyether foam
- Fill volume: 80 mL
- Initial cells density: 5000 cells per mililiters
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6
- other: The flasks were repositioned each day to minimize differences in test conditions.

GROWTH MEDIUM
- Standard medium used: OECD medium in accordance with OECD 201

TEST MEDIUM / WATER PARAMETERS
- Intervals of water quality measurement: pH was recorded at the beginning and the end of the test.

OTHER TEST CONDITIONS
- Photoperiod: continuous illumination
- Light intensity and quality: 7700 - 85000 lux
- other: Algae were maintained suspended under continuous orbital stirring.

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: Cell biomass was measured every day in each flask using an electronic particle counter.

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 3.2
- Range finding study
- Test concentrations: 0.02, 0.2, 2 and 20 mg/L
- Results used to determine the conditions for the definitive study: Growth rate inhibition: 7.59% Inhibition at 0.02 mg/L, 2.91% Inhibition at 0.2 mg/L, 3.65% at 2 mg/L and 56.01% at 20 mg/L

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

9.76 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

31.25 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other:

Remarks:

95% CL 27.93 - 33.29 mg/L

Effect concentrations 3

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

14.96 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other:

Remarks:

95% CL 11.86 – 26.98 mg/L

Details on results:

- Observation of abnormalities (for algal test): No abnormal appearance of the algae at the start and at the end of the test for all concentrations.

Results with reference substance (positive control):

- Results with reference substance valid? yes
- EC50 (72h) = 1.07 mg/L (95% CL 0.94 – 1.2); starting date 18 May 2018

Reported statistics and error estimates:

EC10 (Effect Concentration for 10% effect), EC50 and confidence limits were obtained by calculation according to Regtox® Macro (“Vindimian”), using the Hill model.
The statistical evaluation (NOEC - No Observed Effect Concentration - and the LOEC - Lowest Observed Effect Concentration - determination) was conducted with R software.

Any other information on results incl. tables

The components were not detectable at low concentrations and the evaluation of the endpoints were based on nominal loading rates.

Table 1: 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.	The growth multiplication factor in the control within the 72-hour test period was 288.	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%	The mean coefficient of variation for section-by-section specific growth rates (days 0-1, 1- 2 and 2-3) in the control was 11.2%.	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%.	The coefficient of variation of the average specific growth rates in the control during the whole test period was less than 6.16%.	yes

 

Table 2: Results for the controls after 72h

	Number of cells at 0 h	Measure at 24 h (cells / mL)	Measure at 48 h (cells / mL)	Measure at 72 h (cells / mL)	Specific growth rate 0 h – 24 h	Specific growth rate 24 h – 48 h	Specific growth rate 48 h – 72 h	Growth rate (day-1) after 72h	CV growth 72h (%)	Yield (cells / mL) after 72h	CV yield 72h (%)
Control	5000	33112	210200	1705000	1.890	1.848	2.093	1.944	6.2	1700000	28.7
	5000	23328	129500	1133000	1.540	1.714	2.169	1.808		1128000
	5000	23432	137700	738800	1.545	1.771	1.680	1.665		733800
	5000	26112	243400	1629000	1.653	2.232	1.901	1.929		1624000
	5000	33032	247400	1702000	1.888	2.014	1.929	1.943		1697000
	5000	24616	179900	1743000	1.594	1.989	2.271	1.951		1738000
Mean	5000	27272	191350	1441800	1.685	1.928	2.007	1.873		1436800

 

Table 3: Results for all test concentrations after 72h

Nominal loading rates (mg test item/L after 72h)	Number of cells at 0 h	Measure at 24 h (cells / mL)	Measure at 48 h (cells / mL)	Measure at 72 h (cells / mL)	Growth rate (day-1) after 72h	CV growth 72h (%)	Growth rate inhibition (%) compared to control after 72h	Yield (cells / mL) after 72h	CV yield 72h (%)	Yield inhibition (%) compared to control after 72h
0.950	5000	33144	344800	1453000	1.891	9.1	-0.92	1448000	50.0	-0.78
	5000	29952	137600	2412000	2.060		-9.94	2407000		-67.53
	5000	34920	142800	856800	1.715		8.48	851800		40.72
Mean	5000	32672	208400	1573933	1.888		-0.79	1568933		-9.20
3.050	5000	22968	391500	865300	1.718	9.2	8.30	860300	46.8	40.12
	5000	36248	265800	2421000	2.061		-10.01	2416000		-68.15
	5000	25264	253600	1719000	1.947		-3.91	1714000		-19.29
Mean	5000	28160	303633	1668433	1.908		-1.87	1663433		-15.77
9.760	5000	22488	133300	1123000	1.805	3.6	3.66	1118000	18.0	22.19
	5000	17272	128500	791500	1.688		9.89	786500		45.26
	5000	16224	140400	1073000	1.790		4.47	1068000		25.67
Mean	5000	18661	134067	995833	1.761		6.01	990833		31.04
31.700	5000	5888	1280	127100	1.079	13.9	42.43	122100	44.4	91.50
	5000	14913	1240	62480	0.842		55.07	57480		96.00
	5000	0*	1280	67760	0.869		53.62	62760		95.63
Mean	5000	6934	1267	85780	0.930		50.37	80780		94.38
100.420	5000	0*	1760	120	0.000	-	100.00	0	-	100.00
	5000	0*	17400	160	0.000		100.00	0		100.00
	5000	0*	1400	80	0.000		100.00	0		100.00
Mean	5000	0	6853	120	0.000		100.00	0		100.00

 

Table 4: Analytical results

Treatment		Control	Test substance
ID		C06	C07	C08	C09	C10	C11
Actual loading rate [mg test item.L-1]		0	0.95	3.05	9.76	31.7	100.42
0h  analyzed concentrati on	[mg monoester.L-1]	< LOQ	< LOQ	< LOQ	0.32	3.66	16.17
	[mg diester.L-1]	< LOQ	< LOQ	< LOQ	1.95	8.91	25.37
72h analyzed concentrati on [mg test item.L-1]	[mg monoester.L-1]	< LOQ	< LOQ	< LOQ	< LOQ	< LOQ	0.26
	[mg diester.L-1]	< LOQ	< LOQ	< LOQ	< LOQ	< LOQ	4.81

Limit of quantification (LOQ) =0.1 mg.L-1 for monoester, and 1 mg.L-1 for diester.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Remarks:

For further details please refer to “Any other information on results incl. tables”.