Benzaldehyde, 3-ethoxy-4-(.beta.-D-glucopyranosyloxy)-

Toxicity to aquatic algae and cyanobacteria

Link to relevant study record(s)

Reference

Endpoint:

toxicity to aquatic algae and cyanobacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

July-September 2018

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Version / remarks:

March 23, 2006 (Annex 5 corrected on July 28, 2011)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

yes

Details on sampling:

The test solutions were subjected for active ingredient analysis using the validated analytical method. For main study, six replicates for treatment and control groups were prepared. 10 mL of test samples from each replicates were drawn and mixed together for each group. Collected samples were centrifuged at 2000 rpm for 10 minutes in order to remove algal cell. The representative samples were divided into two equal portions. One portion was sent for test concentration analysis at 0, 24, 48 and 72 h and the second portion was stored at -20 ± 5 ºC. Active ingredient concentration in test media was determined using the validated analytical method.

Vehicle:

yes

Remarks:

algal medium

Details on test solutions:

An amount of 100 mg ethyl vanillin glucoside was transferred to a 10 mL volumetric flask and the volume was made up to the mark with the algal cultured medium to obtain the nominal concentration of 10.0 mg/mL. The volume of 1500 µL from the stock and 0.6 mL alga culture were transferred using a micropipette and diluted to 150 mL with sterile algal culture medium to obtain the test concentration of 100.0 mg/L. Only 0.6 mL alga culture was transferred using a micropipette and diluted to 150 mL with sterile algal culture medium for control group. Six replicates for the control group and the treatment groups were used. The experiment was conducted in 250 mL conical flasks.

Test organisms (species):

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

Details on test organisms:

TEST ORGANISM
- Common name: Pseudokirchneriella subcapitata
- Strain: ATCC 22662
- Source (laboratory, culture collection): American Type Culture Collection, 10801, University of Boulevard, Manassas, Virginia, 20110-2209, USA
- Age of inoculum (at test initiation): Date of Receipt (at JRF) - March 10, 2017; Date of Last Subculture - August 04, 2018
- Method of cultivation: Static

ACCLIMATION
The pre-culture was prepared 2 days prior to the commencement of the study by transferring 1 mL from the latest sub culture into a new culture vessel. The pre-culture was incubated under the same conditions as those required for the test and were used when growing exponentially (5 x 103 - 104 cells/mL). The temperature for pre-culture ranged between 21 - 23 °C.

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Remarks on exposure duration:

N/A

Post exposure observation period:

N/A

Test temperature:

21-23 °C

pH:

7.41-7.54

Salinity:

N/A

Nominal and measured concentrations:

Nominal 100 mg/L

Details on test conditions:

TEST SYSTEM
- Test vessel: 250 mL conical flasks
- Initial cells density: 5360 cells/mL
- No. of vessels per concentration (replicates): 6
- No. of vessels per control (replicates): 6

GROWTH MEDIUM
- Standard medium used: yes

TEST MEDIUM / WATER PARAMETERS
- Source/preparation of dilution water:
- Total organic carbon:
- Particulate matter:
- Metals:
- Pesticides:
- Chlorine:
- Alkalinity:
- Ca/mg ratio:
- Conductivity:

OTHER TEST CONDITIONS
- Sterile test conditions: yes/no
- Photoperiod:
- Light intensity and quality: 6680-6830 lux

EFFECT PARAMETERS MEASURED (with observation intervals if applicable) :
- Determination of cell concentrations: manual counting using a haemocytometer and a microscope

TEST CONCENTRATIONS
A preliminary range finding study was conducted with the test concentrations of 0.0 (control), 0.1, 1.0, 10.0, 50.0 and 100.0 mg ethyl vanillin glucoside/L. Two replicates were run for each concentration of the test item and three replicates for the control.
The percent inhibition of biomass was 1.86, 3.10, 5.27, 4.96 and 4.03 for the test concentrations of 0.1, 1.0, 10.0, 50.0 and 100.0 mg ethyl vanillin glucoside/L, respectively.
The percent inhibition of growth rate was 0.29, 0.58, 1.01, 1.16 and 1.01 for the test concentrations of 0.1, 1.0, 10.0, 50.0 and 100.0 mg ethyl vanillin glucoside/L, respectively.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Key result

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

> 100 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Details on results:

There was no significant alteration observed in algal growth (biomass), yield, and growth rate of ethyl vanillin glucoside exposed group as compared to control group. The ethyl vanillin glucoside does not inhibit the growth of alga (Pseudokirchneriella subcapitata) up to the concentration of 100.0 mg/L.

Results with reference substance (positive control):

- Results with reference substance valid
- 72-hr EC50: 1.15 mg/L (groth rate); 0.49 mg/L (yield)
- Other: NOEC 0.1 mg/L

Validity criteria fulfilled:

yes

Conclusions:

EC50, NOEC and LOEC: Greater than 100.0 mg ethyl vanillin glucoside/L.

Executive summary:

There was no significant alteration observed in algal growth (biomass), yield, and growth rate of ethyl vanillin glucoside exposed group as compared to control group. The ethyl vanillin glucoside does not inhibit the growth of alga (Pseudokirchneriella subcapitata) up to the concentration of 100.0 mg/L. The EC₅₀, NOEC and LOEC value was greater than 100.0 mg/L.

Description of key information

No toxic effects in algae seen at the highest concentration tested 100 mg/L.

Key value for chemical safety assessment

EC50 for freshwater algae:

100 mg/L

EC10 or NOEC for freshwater algae:

100 mg/L