Octadecanoic acid, reaction products with 2-amino-2-methyl-1-propanol

Short-term toxicity to aquatic invertebrates

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From November 29, 2017 to December 01, 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

not specified

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Remarks:

High-performance liquid chromatography (HPLC)

Details on sampling:

To demonstrate that nominal exposure concentrations were being achieved the concentrations of test substance in the test vessels were measured using the high-performance liquid chromatography method. At study start, samples were taken from excess test solutions and at study end from the test vessels of the dilution water control, solvent control and each test concentration.

Vehicle:

yes

Remarks:

Tetrahydrofuran

Details on test solutions:

The study was run with a dilution water control, solvent control and nominal exposure concentrations of 0.0097, 0.031, 0.098, 0.313 and 1.0 mg/L. A primary stock concentrate of test substance, with a nominal concentration of 10 g/L, was prepared by adding a nominal 0.100 g of test substance (actual weight 0.09999 g) and making up to 10 mL with the solvent tetrahydrofuran (THF) in a volumetric flask. The stock was ultrasonicated for 45 minutes and observed to be clear and colourless. The stock was used to prepare the test solutions by direct addition of the appropriate amount, using a microliter syringe, to stirring dilution water in a volumetric flask. The solvent control was prepared in the same way using solvent only. Solvent only additions were also made, as appropriate, such that the final concentration of solvent used in all exposure solutions was 0.1 mL/L with the exception of the dilution water control which contained dilution water only. A solvent was used in this study to assist in dosing the test compound. All test solutions were clear and colourless prior to use.

Test organisms (species):

Daphnia magna

Details on test organisms:

The test organism was the freshwater crustacean, Daphnia magna, obtained from continuous laboratory cultures held at Scymaris. The stock cultures of D. magna were maintained in a reconstituted water medium, the same as the test dilution water, at a temperature of 20 ± 2°C. The cultures were maintained in 2 L glass vessels with a working volume of 1.6 L. A photoperiod of 16 h light:8 h dark, with 20-minute transition periods was provided. The D. magna cultures were fed on a mixed algae diet of Chlorella vulgaris, strain CCAP 211/12 and Pseudokirchneriella subcapitata, strain CCAP 278/4. The D. magna cultures were fed a daily ration depending on the age and density of the culture. Culture conditions were such that the D. magna reproduction was by diploid parthenogenesis. D. magna <24 h old, obtained from a single culture vessel, were used for testing. The parent animals were 22 ± 1 days old and had been maintained with a twice weekly renewal of reconstituted water medium since birth. The test organisms and the culture from which they were obtained showed no evidence of disease before the test period.

Test type:

static

Water media type:

other: Elendt's M4 D. magna medium

Limit test:

no

Total exposure duration:

48 h

Test temperature:

20±1°C

pH:

7.58 to 8.05

Dissolved oxygen:

8.99 to 9.10 mg/L

Nominal and measured concentrations:

Control, Solvent Control and 0.0097, 0.031, 0.098, 0.313 and 1.0 mg/L (nominal)
Control, Solvent Control and 0, 0.0070, 0.073, 0.26 and 0.88 mg/L (measured)

Details on test conditions:

Apparatus
Glass beakers of 250 mL nominal capacity were used as test vessels, with four replicates per test concentration. Each vessel contained 200 mL of test solution providing a depth of approximately 60 mm. The beakers were covered with loose fitting glass lids. The positions of the treatments were randomly allocated within the test area.

Reference substance (positive control):

no

Key result

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

> 0.88 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat. (total fraction)

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

ca. 0.15 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat. (total fraction)

Basis for effect:

mobility

Remarks on result:

other: Confidence interval: 0.025 – 0.22 mg/L

Remarks:

Linear interpolation (ICPIN)

Key result

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

ca. 0.073 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat. (total fraction)

Basis for effect:

mobility

Key result

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

ca. 0.007 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat. (total fraction)

Basis for effect:

mobility

Details on results:

Analytical data
The limit of quantification (LOQ) of Test substance in this study was 0.01 mg/L. The instrument LOQ was 0.005 mg/L but during analysis, samples from the control and each test concentration were diluted ×2, doubling the LOQ. All analytical values are quoted to two significant figures and percentages to the nearest integer. Analytical calibrations were constructed using a minimum of 5 calibration levels, with a minimum R2 value of 0.99. The maximum percentage difference from nominal concentration for standards at the LOQ was less than 30% and less than 20% at levels greater than the LOQ. All analytical values are quoted to two significant figures and percentages to the nearest integer. The measured concentration at the start of the study for the nominal 0.0097 mg/L test solution was
Biological data
Based on immobility compared to the control (p <0.05) the 48 h No Observed Effect Concentration (NOEC) was determined to be 0.043 mg/L and the Lowest Observed Effect Concentration (LOEC) was 0.097 mg/L. There was no immobility observed in the dilution water control. No other symptoms of toxicity were observed.

Analytical results

Nominal concentration of Test substance (mg/L)	Measured concentration of Test substance (mg/L)				Mean measured concentration (mg/L)	Mean measured concentration (%)
	0 h		48 h
	(mg/L)	% of nominal	(mg/L)	% of nominal
Control	<LOQ	-	<LOQ	-	0	-
Solvent Control	<LOQ	-	<LOQ	-	0	-
0.0097	<LOQ	0	<LOQ	0	0	0
0.031	0.014	45	<LOQ	0	0.0070	23
0.098	0.080^a	81	0.066^b	68	0.073	74
0.313	0.28	90	0.25	79	0.26	84
1.0	0.94	94	0.82	82	0.88	88

All measurements are quoted to 2 significant figures

a Mean of triplicate analyses:0.081, 0.081, 0.077 mg/L

b Mean of triplicate analyses:0.068, 0.067, 0.063 mg/L

The limit of quantification in the study was 0.01 mg/L. The instrument LOQ was 0.005 mg/L but during analysis, samples were diluted×2, doubling the LOQ. Where measured concentrations were less than the LOQ, zero values were used to calculate the mean. Geometric means are used except when a zero is present and necessitates an arithmetic mean.

Daphnia magna response

Time (h)	Nominal concentration of Test substance (mg/L)	Mean measured concentration of Test substance (mg/L)	Number immobilised per replicate				Total number tested	Total number immobilised	Percentage immobilised
			A	B	C	D
24	Control	0	0	0	0	0	20	0	0
	Solvent Control	0	0	0	0	0	20	0	0
	0.0097	0	0	0	0	0	20	0	0
	0.031	0.0070	0	0	0	0	20	0	0
	0.098	0.073	0	0	0	0	20	0	0
	0.313	0.26	1	0	0	0	20	1	5
	1.0	0.88	2	2	1	0	20	5	20
48	Control	0	0	0	0	0	20	0	0
	Solvent Control	0	0	0	0	0	20	0	0
	0.0097	0	0	0	0	0	20	0	0
	0.031	0.0070	0	0	0	0	20	0	0
	0.098	0.073	3	2	1	1	20	7	35
	0.313	0.26	3	3	4	4	20	14	70
	1.0	0.88	4	4	5	4	20	17	85

Validity criteria

As no immobility or other signs of stress were observed in the control and dissolved oxygen concentration remained at ≥3 mg/L, this test has satisfied all OECD Guideline 202 validity criteria.

Validity criteria fulfilled:

yes

Conclusions:

Under study conditions, the 48 h EC50 of the test substance for Daphnia magna was determined to be 0.15 mg/L (measured).

Executive summary:

A study was conducted to determine the acute toxicity of test substance, C16-18 AMP, to Daphnia magna, according to OECD Guideline 202, in compliance with GLP. Twenty test organisms were exposed to nominal test substance concentrations of 0, 0.0097, 0.031, 0.098, 0.313 and 1 mg/L for 48 h under static conditions. Analytical dose verification was conducted via HPLC. The mean measured test substance concentrations were determined to be 0, 0.0070, 0.073, 0.26 and 0.88 mg/L. Immobilisation was recorded at 24 and 48 h and compared with control values. Based on immobility compared to the control (p <0.05), the 48 h NOEC was 0.0070 mg/L (measured) and the LOEC was 0.073 mg/L (measured). No other symptoms of toxicity were observed. Based on the study results, the 48 h EC50 was calculated to be 0.15 mg/L (measured). As no immobility or other signs of stress were observed in the control and dissolved oxygen concentration remained at ≥3 mg/L, the test satisfied all validity criteria. Under study conditions, the 48 h EC50 of the test substance for Daphnia magna was determined to be 0.15 mg/L (measured) (Scymaris, 2017).

Description of key information

Based on study results, the 48 h EC50 of the test substance for Daphnia magna was determined to be 0.15 mg/L (measured).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

0.15 mg/L

Additional information

A study was conducted to determine the acute toxicity of test substance, C16-18 AMP, to Daphnia magna, according to OECD Guideline 202, in compliance with GLP. Twenty test organisms were exposed to nominal test substance concentrations of 0, 0.0097, 0.031, 0.098, 0.313 and 1 mg/L for 48 h under static conditions. Analytical dose verification was conducted via HPLC. The mean measured test substance concentrations were determined to be 0, 0.0070, 0.073, 0.26 and 0.88 mg/L. Immobilisation was recorded at 24 and 48 h and compared with control values. Based on immobility compared to the control (p <0.05), the 48 h NOEC was 0.0070 mg/L (measured) and the LOEC was 0.073 mg/L (measured). No other symptoms of toxicity were observed. Based on the study results, the 48 h EC50 was calculated to be 0.15 mg/L (measured). As no immobility or other signs of stress were observed in the control and dissolved oxygen concentration remained at ≥3 mg/L, the test satisfied all validity criteria. Under study conditions, the 48 h EC50 of the test substance forDaphnia magnawas determined to be 0.15 mg/L (measured) (Scymaris, 2017).​