monoesters of C16 and C18 (branched and linear) fatty acids with decan-1-ol

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:

21 - 23 Sep 2011

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: Council Regulation (EC) No 440/2008, Acute toxicity for Daphnia

Deviations:

no

GLP compliance:

yes

Analytical monitoring:

no

Vehicle:

no

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Waterflea
- Source: CEFAS Laboratories, Lowestoft
- Date of gravid isolation: 20 Sep 2011
- Age of Daphnia at test start: Less than 24 h
- Culture conditions: Cultured under static conditions (20 °C, > 60% ASV, 16 h light and 8 h dark photoperiod)
- Feeding regime: A suspension of Chlorella vulgaris (as 1 mg organic carbon/L) every working day, until 24 h prior test start. The Daphnia were not fed during the test.

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Hardness:

156 mg/L CaCO3

Test temperature:

20 ± 1 °C

pH:

7.3 - 7.8

Dissolved oxygen:

60% air saturation

Nominal and measured concentrations:

0, 7, 13, 25, 50, and 100 mg/L (nominal)

Details on test conditions:

TEST SYSTEM
- Test vessel: 60 mL disposable plastic vessel, filled with 25 mL test medium and covered with a transparent perspex sheet
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: The stocks of animals were cultured and the tests performed in reconstitued ISO water. The water was adjusted to 18 - 22 °C, aerated until the dissolved oxygen concentration had reached a minimum of 60% air saturation and the pH stabilised between 6 and 9.
- Hardness: 156 mg/L CaCO3
- Culture medium different from test medium: Culture medium same as test medium.
- Intervals of water quality measurement: Water quality, pH, and dissolved oxygen were measured in pooled replicates for each test and control solution immediately before the test and at the end of the 48 h test period. Temperature was recorded at 0,2 4, and 48 h.

OTHER TEST CONDITIONS
- Adjustment of pH: The pH stabilised between 6.0 and 9.0 during aeration of the test water.
- Photoperiod: 16 h light and 8 h dark

EFFECT PARAMETERS MEASURED:
- Immobilisation: After 24 h and 48 h

RANGE-FINDING STUDY
- Test concentrations: 0, 0.1, 1, 10 and 100 mg/L (48 h)
- Results used to determine the conditions for the definitive study: Yes, 100% immobilisation at 100 mg/L after 48 h and no effects at lower concentrations. Data from the preliminary study identified the EC50 (48 h) as being between 10 and 100 mg/L.

Reference substance (positive control):

yes

Remarks:

Potassium Dichromate

Key result

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

None (0%) of the twenty control Daphnia maintained in dilution water were immobilised during the study, and no Daphnia were trapped at the surface of the water in the control vessels. Thus, the validity criteria of the study which states that control immobilisation must not exceed 10% at the end of the test was fulfilled.

The full water quality measurements are given in the summary tables (see any other infomation on results section) and were within acceptable limits. Specifically, the dissolved oxygen concentration remained greater than 3mg/l, which fulfils the validity criteria of the study.

Results with reference substance (positive control):

Please see "Any other information on results section" for reference test results table.

Reported statistics and error estimates:

The ECx values with 95% confidence limits were calculated according to the methods of ToxCalcTM Version 5.0 "Comprehensive Toxicity Data Analysis and Database Software", copyright 1994-1996.

VALIDITY CRITERIA

The test met the validity criteria defined by the guideline and is thus considered valid and reliable (Table 1).

Table 1: Validity criteria for OECD 202.

Criterion from the guideline	Outcome	Validity criterion fulfilled
In the control, including the control containing the solubilising agent, not more than 10% of the daphnids should have been immobilized.	0% immobilization was recorded in the control vessels.	Yes
The dissolved oxygen concentration at the end of the test should be ≥ 3 mg/L in control and test vessels.	The dissolved oxygen concentration was ≥ 3 mg/L.	Yes

 

WATER QUALITY DATA

Water quality data are summarized below (Tables 2 – 4). Water quality parameters were measured in pooled replicates for each test and control solution and were carried out immediately prior to initiating the test, at 24 h and at the end of the 48 h test period.

Table 2. Summary of pH values

Exposure period [h]	Concentration [mg/L]
	Control	7	13	25	50	100
0 (fresh)	7.8	7.7	7.6	7.6	7.5	7.5
48 (aged)	7.3	7.4	7.4	7.4	7.4	7.5

 

Table 3. Summary of dissolved oxygen (DO) values [mg/L].

Exposure period [h]	Concentration [mg/L]
	Control	7	13	25	50	100
0 (fresh)	8.5	8.3	8.6	8.3	8.5	8.5
48 (aged)	8.4	8.3	8.4	8.3	8.3	8.3

 

Table 4. Summary of temperature values [°C].

Exposure period [h]	Concentration [mg/L]
	Control	7	13	25	50	100
0	21.2	21.2	21.2	21.2	21.2	21.2
24	21.7	21.7	21.7	21.7	21.7	21.7
48	21.7	21.7	21.7	21.7	21.7	21.7

 

REFERENCE TEST

Results with the reference item Potassium dichromate are summarized in Table 5. After 48 h, 100% immobilization was observed at 1.2 mg/L.

Table 5. Results with Potassium dichromate (positive control)

Exposure period	EC50 value (95% confidence limits)	NOEC
24 h	1.13 mg/L (0.85 – 2.2)	-
48 h	0.84 mg/L (0.83 – 0.86)	0.5 mg/L

 

BIOLOGICAL RESULTS

Cumulative immobilization data is provided in Table 6 and the corresponding EC50 values are provided in Table 7.

Table 6. Cumulative immobilization.

Concentration	Number immobilized		% immobilisation
[mg/L]	24 h	48 h	24 h	48 h
0	0	0	0	0
7	0	0	0	0
13	0	0	0	0
25	1	2	5	10
50	0	0	0	0
100	0	0	0	0

 

Table 7. EC50 values.

Exposure time [h]	EC50 value [mg/L]	95% confidence limits [mg/L]
24	> 100	not determinable
48	> 100	not determinable

 

Validity criteria fulfilled:

yes

Remarks:

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

Conclusions:

The 48 hour EC50 value of Monoesters of C16 and C18 (branched and linear) fatty acids with decan-1-ol to Daphnia magna was estimated to be >100 mg/L.

Executive summary:

A study was performed to investigate the acute toxicity of Monoesters of C16 and C18 (branched and linear) fatty acids with decan-1-ol to Daphnia magna. The objective of this study was to determine the 48 hour EC50 value, which is defined as the concentration that immobilises 50% of the exposed Daphnia after a 48 hour exposure period at 19 to 21 °C. The test was carried out according to the procedures based on the OECD 202 guideline Daphnia sp. Acute Immobilisation Test, Annex V EEC C2 Acute toxicity for Daphnia and ToxCalc Version 5.0 "Comprehensive Toxicity Data Analysis and Database Software". The 48 hour EC50 value of Monoesters of C16 and C18 (branched and linear) fatty acids with decan-1-ol to Daphnia magna was estimated to be >100 mg/L.

Description of key information

No effects up to the limit of water solubility (nominal, OECD 202, D. magna)

Additional information

One study is available, in which the short-term toxicity of Monoesters of C16 and C18 (branched and linear) fatty acids with decan-1-ol to aquatic invertebrates was assessed according to OECD guideline 202 and GLP in freshwater (key study).

In a static test, the model organism Daphnia magna was exposed to five nominal concentrations of 7, 13, 25, 50, and 100 mg/L for 48 h. No chemical analysis of test item concentrations was performed. For each nominal concentration the required amount of homogenized sample was added to the appropriate amount of dilution water in an aspirator. The aspirators were mixed for 20 – 24 h and then allowed to separate for 4 h. The aqueous phase, avoiding all settled and floating material, was drawn off and used for the test.

After 48 h, no significant immobilization was observed (max 10%), resulting in an EC50 (48 h) of > 100 mg/L and a NOEC (48 h) of ≥ 100 mg/L.

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