Ethyl nicotinate

Toxicity to aquatic algae and cyanobacteria

Administrative data

Endpoint:

toxicity to aquatic algae and cyanobacteria

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 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition 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 Exposure solutions in volumetric flasks prior to division into replicate vessels; 72 Hour Composite of all replicates within
each treatment and control; additional replicate for solution without algae.
Number of Samples Taken from Each Solution: One sample at each interval
Sampling Location: Approximate midpoint from the surface, bottom, and sides of the vessel
Sampling Device: Pipet
Archive Samples Collected: Yes
Quality Control (QC) Samples: Three samples per sampling interval, prepared in dilution
water at nominal concentrations approximating the test concentration range

Test solutions

Vehicle:

no

Test organisms

Test organisms (species):

Pseudokirchneriella subcapitata (previous names: Raphidocelis subcapitata, Selenastrum capricornutum)

Details on test organisms:

TEST ORGANISM
- Common name: Pseudokirchneriella subcapitata, formerly Selenastrum
capricornutum
- Strain: 1648
- Source (laboratory, culture collection): UTEX The Culture Collection of Algae at the University of Texas, Austin, Texas (maintained in stock culture at Smithers Viscient)
- Age of inoculum (at test initiation):
- Method of cultivation: Three days since previous transfer


ACCLIMATION
- Acclimation period: N/A
- Culturing media and conditions (same as test or not): Same
- Any deformed or abnormal cells observed: N.D.

Study design

Test type:

static

Water media type:

other: Algal Assay Procedure (AAP) medium

Limit test:

no

Total exposure duration:

72 h

Test conditions

Hardness:

N/A

Test temperature:

23-25 celsius

pH:

7.1-8.1

Dissolved oxygen:

N/A

Salinity:

N/A

Conductivity:

92-96 µS/cm

Nominal and measured concentrations:

nominal: 0, 3.1, 6.3, 13, 25, 50, 100 mg/L
measured: 0, 2.4, 4.6, 10, 20, 37, 80 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 250-mL glass flasks, fitted with stainless steel caps
which permitted gas exchange
- Material, size, headspace, fill volume: 100 mL
- Aeration: cultures stirred
- Initial cells density: 10,000 cells/mL
- Control end cells density:
- No. of organisms per vessel: 10^6
- No. of vessels per concentration (replicates): 3
- No. of vessels per control (replicates): 6
- No. of vessels per vehicle control (replicates): N/A

GROWTH MEDIUM
- Standard medium used: yes Algal Assay Procedure medium
- Detailed composition if non-standard medium was used:

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water: AAP (Algal Assay Procedure) medium
- Total organic carbon: 0.87 mg/L
- Particulate matter: N.D.
- Metals: None detected
- Pesticides: None detected
- Chlorine:None detected
- Culture medium different from test medium: no
- Intervals of water quality measurement: periodic (monthly)

OTHER TEST CONDITIONS
- Sterile test conditions: yes/no
- Adjustment of pH: yes- to 7.5 +-0.1
- Photoperiod: continuous
Light Intensity (photosynthetically-
active radiation, PAR):60 to 120 µE/m2/S maintained within ± 15%, i.e., 60 to 73 µE/m2/S, measured at initiation and at each 24-hour
interval during the exposure period using a Licor ModelLI-189 photometer and radiation sensor LI-190SA
Light Intensity (lux): Approximately 4870 to 5740 lux, measured at exposure initiation using a Fisher Scientific Traceable dual range
light meter
Bulb Type: Premira VitaLux fluorescent bulbs
Agitation: Continuous, 100 ± 10 rpm on an orbital shaker, rate monitored & recorded daily

- Light intensity and quality:
- Salinity (for marine algae): N/A

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: electronic particle counter;
- Chlorophyll measurement: No
- Other:

TEST CONCENTRATIONS
- Spacing factor for test concentrations: 2
- Justification for using less concentrations than requested by guideline: N/A
- Range finding study
- Test concentrations:0, 0.01, 0.1, 1, 10, 100
- Results used to determine the conditions for the definitive study: yes

Reference substance (positive control):

yes

Remarks:

Zinc Chloride

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

> 74 - < 78 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC20

Effect conc.:

> 79 - < 81 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 3

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 80 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 4

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

ca. 37 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 5

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

ca. 80 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 6

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

> 75 - < 77 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

biomass

Effect concentrations 7

Duration:

72 h

Dose descriptor:

EC20

Effect conc.:

> 76 - < 78 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

biomass

Effect concentrations 8

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 77 - ca. 79 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

biomass

Results with reference substance (positive control):

Reference Substance: Zinc chloride (ZnCl2)
Duration: 96 hours
Date Performed: 26 to 30 May 2017
EC50: 0.076 mg Zn/L, with 95% confidence intervals of
0.069 to 0.083 mg Zn/L (historical mean =0.089 mg/L, March 2005 to present)

A reference test was conducted at Smithers Viscient to evaluate the sensitivity of
Pseudokirchneriella subcapitata. The result was within the expected range for
Pseudokirchneriella subcapitata reported by Greene et. al. (1991); therefore, the culture is
considered of appropriate sensitivity for use in toxicity testing.

Reported statistics and error estimates:

Response Variables Used for Statistical Analyses: 72-hour average specific growth rate and 72-hour yield
Endpoints Determined: No-Observed-Effect Concentration (NOEC), the highest test concentration which demonstrated no statistically adverse
effect (p ≤ 0.05) when compared to the control data ;
Lowest-Observed-Effect Concentration (LOEC), the lowest concentration which demonstrated a statistically adverse effectwhen compared to the control dat
EC10, EC20, EC50 (the concentrations of test substance which caused a 10, 20, or 50% reduction in the response variable compared to the control data)

Any other information on results incl. tables

Prior to NOEC and LOEC determinations, the data were first checked for normality using

Shapiro-Wilk’s Test (U.S. EPA, 2002) and for homogeneity of variance using Bartlett's Test

(U.S. EPA, 2002).  If the data sets passed the tests for homogeneity and normality, then a

parametric statistical test, e.g., Dunnett’s Multiple Comparison Test (U.S. EPA, 2002) was used

to determine the NOEC and LOEC.  If the data did not pass the tests for homogeneity and

normality, then the NOEC and LOEC were determined using an appropriate non-parametric

statistical test, e.g., Dunn’s Test with Bonferroni-Holm’s Adjustment (U.S. EPA, 2002).  All

statistical determinations were made at the 95% level of certainty, except in the case of ShapiroWilk’s

and Bartlett's Tests, where the 99% level of certainty was applied.

If possible, EC10, EC20, and EC50 values were calculated using a nonlinear regression model.

The test concentrations bracketed the EC values so that the EC value came from interpolation

rather than an extrapolation.  The EC10 , EC 20 , and EC 50 values were estimated so that (i) the

95% confidence intervals reported for the EC value did not contain zero and was not overly

wide, (ii) the 95% confidence interval for the predicted mean at the EC10, EC20, or EC50 value did

not contain the control mean and (iii) there was no significant lack-of-fit of regression model to

the data.  If no concentration resulted in a 10, 20, or 50% reduction, the EC values were

empirically estimated to be greater than the highest concentration tested.  CETIS Version 1.8

(Ives, 2013) was used to perform all statistical calculations.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The 72 hour specific growth rate EC50 for Pseudokirchinella subcapita exposed to the test substance is >80mg/L with no Confidence interval calculable. The 72 hour yield EC50 is 79 mg/L with a 95% confidence interval of 77-ND mg/L. The NOEC and LOEC are 37 mg/L and 80mg/L respectively for both growth rate and yield.