2-(2,6-diethyl-4-methyl-phenyl)propanediamide

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:

04 November 2003 to 06 November 2003

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:

no

Qualifier:

according to guideline

Guideline:

EU Method C.2 (Acute Toxicity for Daphnia)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.1010 (Aquatic Invertebrate Acute Toxicity Test, Freshwater Daphnids)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Concentrations: The concentration of the test material in the test solutions were sampled at the end of the test, one replicate of the dilution water control and each test concentration was sampled

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION
- Method: A 1000 mL volume of the single test concentration (100 mg/L) was prepared by the direct addition of the test material to dilution water. This stock solution was stirred for 60 minutes and given 10 minutes ultrasonic treatment. The resultant solution was a clear yellow solution.
- Controls: Dilution water control

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Age at study initiation (mean and range, SD): <24 hours (first instar). Parent animals were 28 ± 1 days old.
- Method of breeding: diploid parthenogenesis
- Feeding during test: The Daphnia were not fed during the course of the study

ACCLIMATION
- Acclimation conditions: The stock cultures of Daphnia were maintained in a reconstituted water medium, identical to the test dilution water at a temperature of 20 ± 1 °C. The cultures were maintained in 2 L glass vessels with a working volume of 1.5 L. A photoperiod of 16 hours light:8 hours dark with 20 minutes dusk and dawn transition periods was provided. The parent animals were maintained with a twice weekly renewal of reconstituted water medium.
- Type and amount of food: Algae Chlorella vulgaris, strain CCAP 211/12 and a commercially available fish food.
- Health during acclimation (any mortality observed): 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:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Hardness:

228.3 mg/L as CaCO3

Test temperature:

20.2, 20.1 and 20.2 °C at 0, 24 and 48 hours respectively. The continuous temperature recorded automatically over the 48 hours remained within 20 ± 1 °C

pH:

7.96 to 8.03

Dissolved oxygen:

9.0 mg/L. At no time during the course of the study was the dissolved oxygen concentration in any of the test vessels less thant 60 % of the air-saturation value.

Nominal and measured concentrations:

100 mg/L nominal concentration tested.

The measured concentration at the start and end of the test was 100 % of the nominal value. The overall mean measured concentration was 100 % of the nominal value. The percentage loss in the measured concentration over the test period was 0 %.
The nominal concentrations were used for the calculated and reporting of results.

Details on test conditions:

TEST SYSTEM
- Type (delete if not applicable): closed (test vessels were covered with loose fitting glass lids)
- Type, material, size, headspace, fill volume of vessel: Borosilicate glass beakers of 250 mL nominal capacity containing 200 mL of test solution.
- Aeration: Not aerated during the test. The dilution water was aerated for >2 hours before use.
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- Loading rate: 25 Daphnia/L

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: The reconstituted water medium used for testing and maintenance of stock cultures was Elendt’s M4 Daphnia medium. The dilution water was analysed prior to the study. The water parameters and water quality are presented in tables 1 and 2 in the field “Any other information on materials and methods incl. tables.”
- Conductivity: 611 µS/cm.
- Culture medium different from test medium: No

OTHER TEST CONDITIONS
- Photoperiod: 16 hours light: 8 hours date with 20 minute dusk and dawn transition periods

EFFECT PARAMETERS MEASURED:
- An assessment of the response of the Daphnia was made 24 and 48 hours after the commencement of the test. Each Daphnia was viewed by eye and was defined as affected in showing no whole body movement, relative to the water, within a period of 15 seconds even is movement of individual appendages was visible. Daphnia so affected were termed immobile. Any overt symptoms of toxicity were also recorded.

Reference substance (positive control):

no

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks:

(immobilisation)

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks:

(immobilisation)

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Remarks:

(immobilisation)

Details on results:

- Behavioural abnormalities: No symptoms of toxicity were observed in this study.

Table 3: Analytical results

Nominal concentration of test material (mg/L)	Measured concentration of test material (mg/L)				Mean measured concentration over the test duration^a(mg/L)	Mean measured concentration as percentage of nominal concentration	Percentage loss in conc over test duration^a
	0 hours	% of nominal	48 hours	% of nominal
Dilution water control	<0.012	-	<0.012	-	<0.012	-	-
100	100^c	100	100^d	100	100	100	0

^aCalculated using the arithmetic mean of the 0 and 48 hour results.

^b100-[(final analysed concentration/concentration at 0 hours)x100

^cMean triplicate analyses.

^dMean triplicate analyses. 

Table 4: Daphnia response

Time (hour)	Nominal concentration of the test material (mg/L)	Number immobilised per replicate				Total number tested	Total number immobilised	Percentage immobilised
		A	B	C	D
24	Dilution water control	0	0	0	0	20	0	0
	100	0	0	0	0	20	0	0
48	Dilution water control	0	0	0	0	20	0	0
	100	0	0	0	0	20	0	0

 

Table 5: Dissolved oxygen concentrations and pH values

Nominal concentration of test material (mg/L)	Dissolved oxygen concentration						pH
	0 hour		48 hour				0 hour	0 hour
	mg/L	%^a	Rep. C		Rep. D			Rep. C	Rep. D
			mg/L	%^a	mg/L	%^a
Dilution water control	9.0	99	9.0	99	9.0	99	8.03	7.96	7.98
100	-	-	9.0	99	9.0	99	7.96	7.98	7.99

^aQuoted as percentage of the 100% air saturation value of 9.1 mg/L at 20 ºC

Validity criteria fulfilled:

yes

Conclusions:

Under the conditions of the test, no immobilisation, mortality or any other signs of toxicity occurred during the test. The 96 h LC50 of the test material could therefore not be derived. The NOEC of the test material to Daphnia magna was determined to be 100 mg/L. The study is considered to be reliable, relevant and adequate for risk assessment and classification and labelling purposes.

Executive summary:

The acute toxicity of the test material to aquatic invertebrates was investigated in Daphnia magna in accordance with the standardised guidelines OECD 202, EU Method C.2 and EPA OPPTS 850:1010. The Daphnia were exposed to the test material in a limit test (100 mg/L) under static conditions. The mean measured concentration of the test substance was 100 % of the nominal exposure concentration; the results and conclusions were therefore based on the nominal concentrations. No immobilisation, mortality or other symptoms of toxicity were observed during the course of the test. The NOEC of the test material under the conditions of the test was therefore determined to be 100 mg/L.

Description of key information

EC50 (48 h): >100 mg/L,  Daphnia magna, OECD 202, Maynard 2003

Additional information

The acute toxicity of the test material to aquatic invertebrates was investigated in water flea (Daphnia magna) in accordance with the standardised guideline OECD 202. The daphnids were exposed to the test material in a limit test (100 mg/L) under static conditions. The mean measured concentration of the test material was 100% of the nominal exposure concentration; the results and conclusions were therefore based on the nominal concentrations. No immobilisation, mortality or other symptoms of toxicity were observed during the course of the test. The NOEC of the test material under the conditions of the test was therefore determined to be 100 mg/L. The available data is considered to be complete and the result determined, 48 h NOEC value 100 mg/L, was taken forward for risk assessment.