Isotridecanol, ethoxylated

Short-term toxicity to fish

Link to relevant study record(s)

Reference

Endpoint:

short-term toxicity to fish

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2021-04-12 to 2021-04-16

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 203 (Fish, Acute Toxicity Test)

Version / remarks:

2019

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

- Concentrations: fresh media at 0 and 72 h and aged media at 24 and 96 h (limit concentration: 1.5 mg/L)
- Sampling method: Samples were taken directly from the test vessels.

Vehicle:

no

Details on test solutions:

PREPARATION AND APPLICATION OF TEST SOLUTION (especially for difficult test substances)
- Method: WAF acc. to OECD guidance document No. 23 (2018). A WAF with a nominal loading rate of 5 mg/L was prepared. This dispersion was shaken for 24 hours with 20 rpm at room temperature. After completion of shaking and a separation phase
of at least 1 hour standing at room temperature, the WAF was removed by siphoning from the middle of the glass flask. Undissolved particles were removed by membrane filtration (membrane filter 0.45 μm, RC, Macherey-Nagel). The filter was saturated in order to avoid adsorption during the filtration. The first 25 mL of the filtrate were discarded. The filtration was interrupted for 10 minutes to allow adsorption and saturation of the filter material with dissolved test item. Thereafter, the filtration was continued. The next 25 mL were discarded. During filtration, the filter was always kept covered. No presence of undissolved test item during the test was observed. The limit loading of the test item was prepared out of the WSF (nominal loading 5.00 mg/L) by dilution and tested in a limit test with a nominal loading of 1.50 mg/L.
- Evidence of undissolved material (e.g. precipitate, surface film, etc.): no

Test organisms (species):

Danio rerio (previous name: Brachydanio rerio)

Details on test organisms:

TEST ORGANISM
- Common name: zebrafish
- Source: originally obtained from Umweltbundesamt, Berlin, Germany
- Age at study initiation (mean and range, SD): Juvenile

ACCLIMATION
- Acclimation period: 9 days
- Acclimation conditions (same as test or not): same
- Type and amount of food during acclimation: commercial fish food, Sera Vipan; SERA GmbH, Germany, 4% of the fish body weight.
- Feeding frequency during acclimation: three times per week
- Health during acclimation (any mortality observed): no mortality observed. No disease treatments were administered throughout holding and testing.

FEEDING DURING TEST (as applicable) : no

Test type:

semi-static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

96 h

Test temperature:

23.0 - 24.2°C

pH:

7.6 - 7.8

Dissolved oxygen:

94 - 100%

Conductivity:

150 μS/cm

Nominal and measured concentrations:

Nominal loading rate: 1.5 mg/L
Geometric mean measured concentration: 1.10 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: aquaria
- Material, size, headspace, fill volume: glass, 3 L, 2.5 L fill volume
- Aeration: gentle aeration
- Renewal rate of test solution (frequency/flow rate): every 24 h
- No. of organisms per vessel: 7
- No. of vessels per concentration (replicates): 1
- No. of vessels per control (replicates): 1
- Biomass loading rate: 0.132 g fish per liter test solution


TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Tap water of local origin was used for holding. The water was filtered on activated charcoal and aerated for at least 24 h to remove chlorine.
- Total organic carbon: < 2 mg/L
- Chlorine: < 0.01 mg/L
- Alkalinity: 0.6 mmol/L
- Intervals of water quality measurement: daily

OTHER TEST CONDITIONS
- Adjustment of pH: no
- Photoperiod: light / dark cycle: 16 / 8 h
- Light intensity: 540 – 1000 Lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : Mortality and symptoms of intoxciation after 2 ± 0.5 h and 5 ± 1 h after the start of the exposure. On days 1-4 of the test, all vessels with living fish were inspected twice per day.

Reference substance (positive control):

no

Duration:

96 h

Dose descriptor:

LL50

Effect conc.:

> 1.5 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Duration:

96 h

Dose descriptor:

LL50

Effect conc.:

> 1.1 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mortality (fish)

Details on results:

- Mortality of control: no

Sublethal observations / clinical signs:

Table 1: Measured Concentrations of the Test Item Isotridecanol, ethoxylated (2EO) during the Definitive Test

	0 h  fresh medium		24 h  old medium		72 h  fresh medium		96 h  old medium		Geometric mean measured test item concentration [mg/L]
Nominal concentration [mg/L]	Measured conc. [mg/L]	[%]	Measured conc. [mg/L]	[%]	Measured conc. [mg/L]	[%]	Measured conc. [mg/L]	[%]
1.50	1.27	85	1.01	68	1.31	88	0.861	57	1.10
Control	< LOQ		< LOQ		< LOQ		< LOQ		< LOQ

Table 2: Validity criteria for OECD 203.

Criterion from the guideline	Outcome	Validity criterion fulfilled
The mortality in the control(s) should not exceed 10% (or one fish if less than ten are used) at the end of the test	0%	yes
The dissolved oxygen concentration must have been at least 60 per cent of the air saturation value throughout the test	≥ 94%	yes
There must be evidence that the concentration of the substance being tested has been satisfactorily maintained, and preferably it should be at least 80% of the nominal concentration throughout the test. If the deviation from the nominal concentration is greater than 20%, results should be based on the measured concentration.	WAF prepared	yes

 

Validity criteria fulfilled:

yes

Remarks:

Please refer to table 2 at "Any other information on results incl. tables"

Description of key information

LL50 (96h) > 1.1 mg/L (geom. mean measured, OECD 203)

Additional information

The acute toxicity of Isotridecanol, ethoxylated, < 2.5 EO to fish was investigated in a study following OECD 203 (GLP). Fish of the species Danio rerio were exposed to a nominal loading rate of 1.5 mg/L. The study was set up in a semi-static test design with a daily renewal of the test medium. The test concentration was analytically verified by LC-MS/MS. Mortality was not observed. At the end of the 96 hour exposure period a LL50 > 1.1 mg/L (geom. mean measured) was determined.