Isooctyl palmitate

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

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 202 (Daphnia sp. Acute Immobilisation Test)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Isooctyl palmitate

EC Number:

215-675-9

EC Name:

Isooctyl palmitate

Cas Number:

1341-38-4

Molecular formula:

C24H48O2

IUPAC Name:

6-methylheptyl hexadecanoate

Test material form:

liquid

Remarks:

a colourless liquid

Sampling and analysis

Analytical monitoring:

yes

Test solutions

Vehicle:

yes

Details on test solutions:

The stock solution used in the range-finding test was prepared by dissolving 100.4 mg of the test item in 40 mL of dilution water – M4 and the total volume was completed to 1000 mL, resulting in a concentration of 100 mg.L-1. To assist solubilization, the solution was stirred for 20 minutes in a magnetic stirrer and 30 minutes of ultrasonic dispersion was also applied.

The stock solution used in the definitive test was prepared by dissolving 10.3 mg of the test item in 40 mL of dilution water – M4 and the total volume was completed to 1000 mL, resulting in a concentration of 10 mg.L-1. To assist solubilization, the solution was stirred for 30 minutes in a magnetic stirrer and 35 minutes of ultrasonic dispersion was also applied.

The test solutions were prepared from dilutions of the stock solutions. The preparation procedure is described in the raw data and in Tables 1 and 2.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

The test system used for this study is described below, according to Straus (1820):

Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Crustacea
Class: Branchiopoda
Order: Cladocera
Family: Daphniidae
Genus: Daphnia
Species: Daphnia magna

Young Daphnia magna ≤ 24 hours old were obtained from the culture kept at the Ecotoxicology Laboratory, maintenance and cultivation records are archived at BIOAGRI.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Test conditions

Hardness:

236.2 mg.L-1 CaCO3

Test temperature:

20.4°C

pH:

7.7 to 7.8

Dissolved oxygen:

8.1 mg.L-1

Nominal and measured concentrations:

Nominal and Effective Concentrations of Test Item, and Their Respective Deviations, Dilutions Factor and Chromatograms Results.

Nominal concentrations
(mg.L-1) Concentrations found in the chromatograms
(µg.L-1) Dilutions
factor Effective concentrations (mg.L-1) Average effective concentrations
(mg.L-1) Deviations

(%)
0 48 0 48 0 48
(Hours) (Hours) (Hours)
2 405.59 373.82 4.0000 4.3478 1.6412 1.6442 1.6427 17.86
1 428.28 311.81 2.0000 2.5641 0.8665 0.8088 0.8377 16.23
0.5 195.33 183.23 2.0833 2.2727 0.4117 0.4213 0.4165 16.71
0.25 109.11 84.91 2.0000 2.3810 0.2208 0.2045 0.2126 14.94
0.125 113.65 104.57 1.2500 1.2500 0.1437 0.1322 0.1380 10.38
Control < PLQ < PLQ ---- ---- ---- < PLQ < PLQ

The effective concentrations were determined according to the equations (1 and 2) described in the item 5.8.1 and exemplified in the appendix 1;
The average effective concentrations were the average of concentrations at 0 and 48 hours;
|Dev| = [(Cts (average) – Cnom) x 100] / Cnom
PLQ = practical limit of quantification (53.223 µg.L-1)

Details on test conditions:

Test Conduction

In the range-finding test the exposure conditions were:

a) Total number of organisms per each tested concentration or control: 10;
b) Number of replicates per each tested concentration and control: 2;
c) Number of organisms per test container: 5;
d) Volume: 15 mL of test solution per test container, 3 mL to each Daphnia;
e) The organisms were distributed randomly in the test container. Firstly, three organisms were placed in each test container and, finally, two organisms were added to the container;
f) Nominal used concentrations: control; 0.01; 0.1; 1; 10 and 100 mg.L-1;
g) Temperature of the test solutions: 20.2 to 20.6°C;
h) Photoperiod: 16 hours of light and 8 hours of dark;
i) Parameters evaluated: immobility after 24 and 48 hours; and still animals were considered unable to swim for a period of 15 seconds of observation after mild agitation of the flasks.

In the definitive test the exposure conditions were:

a) Total number of organisms per each tested concentration or control: 20;
b) Number of replicates per each tested concentration and control: 4;
c) Number of organisms per test container: 5;
d) Volume: 15 mL of test solution per test container, 3 mL to each Daphnia;
e) The organisms were distributed randomly in the test container. Firstly, three organisms were placed in each test container and, finally, two organisms were added to the container;
f) Nominal used concentrations: control; 0.125; 0.25; 0.5; 1 and 2 mg.L-1;
g) Temperature of the test solutions: 20.3 to 20.6°C;
h) Photoperiod: 16 hours light and 8 hours dark;
i) Parameters evaluated: immobility after 24 and 48 hours; and still animals were considered unable to swim for a period of 15 seconds of observation after mild agitation of the flasks;
j) Analytical determination: content dissolved oxygen, pH of the test solutions and the test item concentration were determined at the beginning of the test and after 48 hours.

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Results and discussion

Effect concentrations

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

ca. 0.71 mg/L

Details on results:

The value of 24-hours LC50 of Isooctyl palmitate was not determined because the highest tested concentration of 2 mg.L-1 caused only 45% immobility to organisms. The 48-hours EC50 value of 0.71 mg.L-1 (95% confidence limits = 0.58 to 0.85 mg.L-1).

In the definitive test the highest tested concentration that did not cause acute effect (immobility) to the organisms after 48 hours was 0.25 mg.L-1. The lowest concentration that caused 100% immobility was 2 mg.L-1.

Results with reference substance (positive control):

The 24-hours EC50 value of the reference item (potassium dichromate) was 0.93 mg.L-1 (95% confidence limits = 0.79 to 1.09 mg.L-1), showing the sensitivity of the test system (ISO 6341 / OECD 202, 2004).

Any other information on results incl. tables

Criteria for Validity of the Test

 

The test was valid to taking care of the following conditions:

 

·  In the control it was not exceed 10 per cent of immobilized on organism;

 

·  The dissolved oxygen concentration at the end of the test was ≥ 3 mg.L^{-inthe control and the concentrations test.}

 

Note:For the first item more then 10 per cent of daphnia did not show an immobilized in the control or others sings of disease or stress, for example, discoloration or unusual behavior such as trapping at surface of water.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The 48-hours EC50 value of Isooctyl palmitate was 0.71 mg.L-1 (95% confidence limits = 0.58 to 0.85 mg.L-1).