Hexanamide, N-(2-hydroxyethyl)-3,5,5-trimethyl-

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:

22 January 2013-14 February 2013

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)

Version / remarks:

2004

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Measured concentrations: 0, 5.64, 11.5, 22.4, 44.0, 89.7 mg/L
- Sampling method: duplicate aliquots (ca 20 mL) were removed from each prepared concentration at the commencement of the test as 0 h samples. At termination of the definitive test, an aliquot (ca 15 mL) was removed from each replicate vessel at each concentration and combined. Duplicate aliquots (ca 20 mL) were removed from the combined solutions as 48 h samples.
- Sample storage conditions before analysis: Samples analysed on receipt.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: test solutions prepared by dilution of a 100 mg/L nominal stock solution of the substance coating additives, with Elendt M4 medium, producing nominal test concentrations of 6.25, 12.5, 25, 50 and 100 mg/L, with an untreated control. The 100 mg/L nominal stock solution of the substance coating additives was prepared by adding the substance coating additives (99.98 mg) to Elendt M4 (1 L) followed by ultrasonication for ca 10 min to aid dissolution. Four vessels containing 100 mL of treated media, untreated media for the control, were prepared for each treatment group. Five D. magna neonates (<24 h old) were added to each vessel within 30 min of preparation of the test vessels.
- Controls: Elendt M4 medium.

Test organisms (species):

Daphnia magna

Details on test organisms:

D. magna (water flea) were used for this study. They were bred within the laboratory by
acyclical parthenogenesis and the neonates used were <24 h old at test initiation.

Test type:

static

Water media type:

not specified

Limit test:

no

Total exposure duration:

48 h

Post exposure observation period:

Test vessels were observed for immobile D. magna at 24 and 48 h after test initiation. D. magna were recorded as immobile if no movement was observed within 15 seconds following gentle agitation of the test vessel and after gently touching with a glass rod.

Hardness:

293 mg CaCO3/L

Test temperature:

20.2-20.8°C

pH:

7.44-7.81

Dissolved oxygen:

72.4-96.2%

Nominal and measured concentrations:

Nominal concentrations: 0, 6.25, 12.5, 25, 50 and 100 mg/L
Measured concentrations: 0, 5.64, 11.5, 22.4, 44.0 and 89.7 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel:Glass crystallising dishes of ca 200 mL capacity, covered with Perspex lids
- Type (delete if not applicable): Open
- Aeration: No
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- Laboratory temperature: 18-22°C
- Light cycle of test room: 16 h light and 8 h dark was in operation throughout the test,provided by artificial daylight fluorescent tubes
- Light intensity: 677 lux

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Deionised water used to prepare Elendt M4 Medium
- Conductivity: 524-544 µS/cm
- Culture medium different from test medium: No
- Intervals of water quality measurement: Initiation, 24 h and 48 h


TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2
- Range finding study
- Test concentrations: 0, 0.1, 1.0, 10 and 100 mg/L
- Results used to determine the conditions for the definitive study: After 48 h exposure, no immobile D. magna were recorded at any test concentration.

Reference substance (positive control):

no

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 89.7 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

other: immobilisation

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

44 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

other: immobilisation

Details on results:

-Mortality of control: 0

Measured Concentrations of the substance Coating Additives During the Test

Nominal Concentration of the substance coating additives (mg/L)	Time (h)	Mean Measured Concentration of the substance coating additives (mg/L)	Overall Mean Measured Concentration of the substance coating additives (mg/L)	Deviation of 48 h Measured Concentration from 0 h Measured Concentration (± %)
Control	0	ND	ND	NA
	48	ND
6.25	0	6.00	5.64	-12
	48	5.28
12.5	0	12.3	11.5	-13
	48	10.7
25	0	24.0	22.4	-13
	48	20.8
50	0	47.3	44.0	-14
	48	40.7
100	0	94.6	89.7	-10
	48	84.8

ND = Not detected

NA = Not applicable

 D. magna Recorded During the Test

Time (h)	Replicate Vessel	Mean Measured Concentration of the substance Coating Additives (mg/L)
		Control	5.64	11.5	22.4	44.0	89.7
24	I II III IV	0 0 0 0	0 0 0 0	0 0 0 0	0 0 0 0	0 0 0 0	0 0 0 1
	% ImmobileD. magna	0	0	0	0	0	5
48	I II III IV	0 0 0 0	0 0 0 0	0 0 0 0	0 0 0 0	0 0 0 0	2 2 2 3
	% ImmobileD. magna	0	0	0	0	0	45

Five D. magna in each of 4 replicates were tested at each concentration

Water Quality Parameters Recorded during the Test

Time/Parameter	Mean Measured Concentration of the substance coating additives (mg/L)
	Control	5.64	11.5	22.4	44.0	89.7
0 h   pH Temperature (°C) Conductivity (µS/cm) Dissolved Oxygen (% ASV*)	7.96 20.0 631 93.9	7.98 19.8 629 96.2	7.97 19.8 634 91.3	7.97 19.9 634 89.7	7.99 20.1 636 92.0	7.98 19.8 633 91.8
24 h   pH Temperature (°C) Conductivity (µS/cm) Dissolved Oxygen (% ASV*)	7.76 19.9 623 72.4	7.82 19.8 628 73.0	7.83 19.7 625 74.8	7.86 19.6 626 79.0	7.87 19.6 625 75.1	7.87 19.7 624 78.7
48 h   pH Temperature (°C) Conductivity (µS/cm) Dissolved Oxygen (% ASV*)	7.84 20.2 599 74.5	7.85 20.2 595 75.2	7.87 20.1 598 76.3	7.93 20.1 600 73.5	7.90 20.1 600 75.7	7.89 20.2 599 78.1

*ASV = Air saturation value

Validity criteria fulfilled:

yes

Conclusions:

Under the study condition, the 48 h EC50 and NOEC for the test substance to D. magna is concluded to be >89.7 and 44 mg/L respectively based on arithmetic mean measured concentrations

Executive summary:

A study was conducted to determine the acute toxicity of test substance to the Daphnia magna according to a method similar to OECD Guideline 202, in compliance with GLP. The study was conducted over a 48 h period under static conditions. Based on the results of a range finding and limit test, the definitive test was conducted with nominal test concentrations of 6.25, 12.5, 25, 50 and 100 mg/L, together with an untreated control. Four test vessels were prepared for each test concentration and 5 daphnia were added to each. The samples for analytical confirmation of actual exposure concentrations were taken at the start (0 h) and at the end of the test (48 h). Chemical analysis of test samples taken at 0 and 48 h indicated that concentrations of the test substance were maintained within the range 86 -91% of the initial measured values. No undissolved test substance was observed in the test tanks throughout the test period. Based on these results, the mean measured concentrations of the test substance were calculated to be 5.64, 11.5, 22.4, 44.0 and 89.7 mg/L, respectively. The daphnia were observed at regular intervals for immobilisation and the test conditions (pH, temperature, conductivity and dissolved oxygen) were measured daily during the test. The test solution quality parameters were within the following ranges: pH: 7.44 -7.81; temperature: 20.2 -20.8°C; conductivity: 524 -544 μS/cm and dissolved oxygen concentration: 77.3 -88.2% of air saturation value. The cumulative number of immobile D. magna recorded at 48 h were 9 (45%) at 89.7 mg/L. No immobile D. magna were recorded in the control, 5.64, 11.5, 22.4 and 44.0 mg/L concentrations throughout the test period. Based on immobilisation being 45% at 100 mg of the test substance/L, an EC50 value could not be determined as immobilisation did not reach 50%. Under the study condition, the 48 h EC50 and NOEC for the test substance to D. magna is concluded to be >89.7 and 44 mg/L respectively based on arithmetic mean measured concentrations (Knight, 2013).

Description of key information

The 48 h EC50 and NOEC of the test substance inDaphnia magnawere determined to be >89.7 and 44 mg/L (measured; arithmetic mean) respectively.  

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

EC50

Effect concentration:

> 89.7 mg/L

Additional information

A study was conducted to determine the acute toxicity of test substance to the Daphnia magna according to a method similar to OECD Guideline 202, in compliance with GLP. The study was conducted over a 48 h period under static conditions. Based on the results of a range finding and limit test, the definitive test was conducted with nominal test concentrations of 6.25, 12.5, 25, 50 and 100 mg/L, together with an untreated control. Four test vessels were prepared for each test concentration and 5 daphnia were added to each. The samples for analytical confirmation of actual exposure concentrations were taken at the start (0 h) and at the end of the test (48 h). Chemical analysis of test samples taken at 0 and 48 h indicated that concentrations of the test substance were maintained within the range 86 -91% of the initial measured values. No undissolved test substance was observed in the test tanks throughout the test period. Based on these results, the mean measured concentrations of the test substance were calculated to be 5.64, 11.5, 22.4, 44.0 and 89.7 mg/L, respectively. The daphnia were observed at regular intervals for immobilisation and the test conditions (pH, temperature, conductivity and dissolved oxygen) were measured daily during the test. The test solution quality parameters were within the following ranges: pH: 7.44 -7.81; temperature: 20.2 -20.8°C; conductivity: 524 -544 μS/cm and dissolved oxygen concentration: 77.3 -88.2% of air saturation value. The cumulative number of immobile D. magna recorded at 48 h were 9 (45%) at 89.7 mg/L. No immobile D. magna were recorded in the control, 5.64, 11.5, 22.4 and 44.0 mg/L concentrations throughout the test period. Based on immobilisation being 45% at 100 mg of the test substance/L, an EC50 value could not be determined as immobilisation did not reach 50%. Under the study condition, the 48 h EC50 and NOEC for the test substance to D. magna is concluded to be >89.7 and 44 mg/L respectively based on arithmetic mean measured concentrations(Knight, 2013).