Ethyl nicotinate

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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Ethyl nicotinate

EC Number:

210-370-7

EC Name:

Ethyl nicotinate

Cas Number:

614-18-6

Molecular formula:

C8H9NO2

IUPAC Name:

ethyl nicotinate

Test material form:

liquid

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Sampling Intervals and Solution Composition: 0-Hour Intermediate vessels prior to division into replicate vessels; 48-Hour Composite of all replicates within each treatment level and control
Number of Samples Taken from Each Solution:Two samples at each interval; one sample for analysis, one sample for archival
Sampling Location: Approximate midpoint from the surface, bottom, and sides of the vessel
Sampling Device: Pipet
Quality Control (QC) Samples: Three samples at each sampling interval prepared in dilution water at nominal concentrations whichapproximated the test concentration range

Test solutions

Vehicle:

yes

Details on test solutions:

Primary Stock Concentration: 100 mg/L
Stock Vessel: Glass beaker
Stock Volume: 2.5 L
Amount of Test Substance Added: 0.2511 g (0.2503 g as active ingredient)
Diluent: Fortified laboratory well water

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

TEST ORGANISM
- Common name: Daphnia magna
- Strain/clone:
- Justification for species other than prescribed by test guideline:
- Source: Smithers Viscient culture
- Age of parental stock (mean and range, SD): < 24 hours old at exposure initiation; immature daphnids were removed from culture 24 hours prior to exposure initiation, thus isolating sexually mature adults. Young produced by the parent organisms were used for the exposure.
- Feeding during test
- Food type: none
- Amount: nil
- Frequency: nil

ACCLIMATION
- Acclimation period: 2 weeks
- Acclimation conditions (same as test or not): same
- Type and amount of food: Unicellular green algae, Ankistrodesmus falcatus
(4 × 10^7 cells/mL);YCT suspension (yeast, cereal leaves, and flaked fish food)
- Feeding frequency: Once daily during culture
- Health during acclimation (any mortality observed):

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

48 h

Remarks on exposure duration:

16 hours light: 8 hours dark

Test conditions

Hardness:

170 as CaCO3 (mg/L)

Test temperature:

20-21 celsius

pH:

8.0 - 8.2

Dissolved oxygen:

8.4 -8.9 mg/L

Salinity:

N/A

Conductivity:

860 µS/cm

Nominal and measured concentrations:

nominal: control, 6.3, 13, 25, 50 and 100 mg/L
measured: control, 5.4, 11, 22, 41, 84 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 250-mL glass beakers
- Material, size, headspace, fill volume: 200 mL
- Aeration: no
- No. of organisms per vessel: 5
- No. of vessels per concentration (replicates): 4
- No. of vessels per control (replicates): 4
- No. of vessels per vehicle control (replicates): n/a
- Biomass loading rate: 25 daphnids/L

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: Fortified laboratory well water
- Total organic carbon: 1.3 mg/L
- Particulate matter: N/A
- Metals: None detected
- Pesticides: None detected
- Chlorine: None detected
- Alkalinity: 84 mg/L as CaCO3
- Ca/mg ratio: N/D
- Conductivity: 860 µS/cm
- Salinity: N/D
- Culture medium different from test medium: no
- Intervals of water quality measurement: periodically

OTHER TEST CONDITIONS
- Adjustment of pH: No
- Photoperiod: 16 hours light: 8 hours dark
- Light intensity: 48 to 60 footcandles (520 to 650 lux) measured around the test area once during the exposure

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) : The biological observations, number of immobilized daphnids, and observations of the physical
characteristics of the exposure and control solutions (e.g., precipitate, film on solution’s surface) were recorded at exposure initiation and at each subsequent 24-hour interval until exposure termination (48 hours), if applicable. Immobilization was defined as the inability to swim within 15 seconds after gentle agitation of the exposure vessel.


VEHICLE CONTROL PERFORMED: N/A

RANGE-FINDING STUDY
- Test concentrations: control, 0.01, 0.1, 1, 10,100 mg/L
- Results used to determine the conditions for the definitive study: yes

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

24 h

Dose descriptor:

EC50

Effect conc.:

> 84 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 2

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 84 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 3

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

ca. 20 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Results with reference substance (positive control):

24 hr EC50 with Potassium Dichromate = 2.1 mg/L. The reference test is used to evaluate the sensitivity of the daphnid population at Smithers
Viscient. This result was within the expected range for daphnids and potassium dichromate.

Reported statistics and error estimates:

The concentrations tested and the corresponding immobilization data derived from the definitive
toxicity exposure were used to estimate the 24- and 48-hour median effect concentrations (EC50).
The EC50 is defined as the concentration of the test substance in dilution water which produces
50% immobilization of the test organism population at the stated time interval. If at least one
test concentration caused immobilization of greater than or equal to 50% of the test population,
then a computer program CETIS version 1.8 (Ives, 2013) was used to calculate the EC50
values and 95% confidence intervals. If no concentration tested resulted in greater than or equal to
50% immobilization, then the EC50 value was empirically estimated to be greater than the
highest concentration tested.

The No-Observed-Effect Concentration (NOEC) during the 48-hour exposure period was also
determined. The NOEC is defined as the highest concentration tested at and below which there
were no differences in sub-lethal or lethal effects with respect to the control organisms. In
addition, the highest concentration tested resulting in 0% immobilization and the lowest
concentration tested resulting in 100% immobilization were determined.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The EC50 values at 24 and 48 hours were determined to be >84 mg/L. the 95 % confidence intervals could ot be determined as the EC50 values were empirically determined. The 48h NOEC value is 20 mg/L.