Boronic acid, B-(2-fluoro-3-methoxyphenyl)-

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

Study period:

17 July 2018 - 20 July 2018

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Freshwater Alga and Cyanobacteria, Growth Inhibition Test)

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: MEP, P.R. China, the Guideline for the Testing of Chemicals, Effects on Biotic Systems (the Second Edition), No. 201 "Alga Growth Inhibition Test". (2013.8)

Test guideline 3

Qualifier:

according to guideline

Guideline:

other: European Commission, Health & Consumer Protection Directorate-General, Guidance document on analytical quality control and validation procedures for pesticide residues analysis in food and feed, SANCO/12571/2013, 19 November 2013 rev.0,

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

(2-fluoro-3-methoxyphenyl)boronic acid

EC Number:

609-099-0

Cas Number:

352303-67-4

Molecular formula:

FC6H3(OCH3)B(OH)2

IUPAC Name:

(2-fluoro-3-methoxyphenyl)boronic acid

Test material form:

solid: particulate/powder

Specific details on test material used for the study:

Lot number: 18051400
Storage: At room temperature 15-25°C
Appearance: Off-white powder
Purity: 100.2%

Sampling and analysis

Analytical monitoring:

yes

Remarks:

HPLC method

Details on sampling:

Six calibration standards of test item, at concentrations of 1, 2, 5, 20, 50 and 100 mg/L, were prepared and analyzed with each sample batch. Linear regression equations were generated using the peak area responses versus the respective concentrations of the calibration standards.

Test solutions

Vehicle:

no

Details on test solutions:

A test item solution of 100 mg/L was prepared with OECD alga growth medium. 0.0504 g of test item was weighed and 500 mL growth medium was added to dissolve the test item. The solution was mixed by magnetic stirring for about 2 hours to make the test item dissolved thoroughly. Pipette 10.0, 22.4, 50.0, 111.8, 250.0 mL of the stock solution of 100 mg/L and make up to 500 mL with OECD alga growth medium. The solutions were mixed thoroughly. The biomass of the pre-cultured alga inoculums was counted and the mean concentration was 251x10(4) cell/ml. 0.996 mL of alga inoculum culture was added into the flask to make the initial biomass to be 5x10 (3)cell/ml in the volume of 500 mL. The control solution was 500 mL growth medium inoculated with the same volume of alga inoculum culture and without test item. The test solution was dispensed into 3 replicates flasks and each replicate contained 100ml test solution. All test flasks were capped with air-permeable membrane. The vessels were placed and incubated under continuous shaking in the incubator.

Test organisms

Test organisms (species):

Desmodesmus subspicatus (previous name: Scenedesmus subspicatus)

Details on test organisms:

Test alga was Desmodesmus subspicatus, which is a freshwater alga species, and is one of the recommended species of Ministry of Environmental Protection of People's Republic of China and the OECD Guidelines for the Testing of Chemicals. The stock alga was originally introduced from Institute of Hydrobiology, Chinese Academy of Sciences and cultured continually in the facility. The test alga batch number was Desmodesmus subspicatus 20180713.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

no

Total exposure duration:

72 h

Post exposure observation period:

Intervals of 24hr, 48hr, 72 hr.

Test conditions

Test temperature:

21-24 °C, maintained at ± 2 C (actual measured was in the range of 22.7-23.4°C)

pH:

7.46 - 8.05

Nominal and measured concentrations:

Based on the results of the preliminary test, the definitive test was carried out at 5
concentrations of 2, 4.5, 10.0, 22.4 and 50 mg/L (nominal concentrations).

The determined concentrations in fresh media were 93.0% ~ 97.4% of nominal concentrations, and the determined concentrations in old media were 83.7% ~ 95.2% of nominal concentrations. The test concentrations were satisfactorily maintained in the range of 80 ~120% of nominal concentration.

Details on test conditions:

Based on the results of the preliminary test, the definitive test was carried out at 5
concentrations of 2, 4.5, 10.0, 22.4 and 50 mg/L (nominal concentration). A concurrent control group was included in parallel. 3 replicates were included in the control and treatment groups.
The alga species used in the test was Desmodesmus subspicatus and the initial cell concentration was 0.5x10 cell/mL. Alga growth medium recommended by OECD was used. During the 72 hours test period, the cell concentration in each flask was determined by manual cell counting by microscope at 24 hours, 48 hours and 72 hours after the start of the
test.

Reference substance (positive control):

yes

Remarks:

3,5-dichlorophenol (3,5-DCP)

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

other: EyC50

Effect conc.:

5.35 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks:

(Yield)

Effect concentrations 2

Duration:

72 h

Dose descriptor:

other: EyC10

Effect conc.:

2.169 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks:

(Yield)

Effect concentrations 3

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

11.675 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 4

Key result

Duration:

72 h

Dose descriptor:

EC10

Effect conc.:

4.236 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Results with reference substance (positive control):

The results of the reference item test (Study Number HI185680010) showed that 72 hour EyC50 of 3,5-DCP to Desmodesmus subspicatus was 1.66 mg/L with the 95% confidence limits 1.22 ~ 2.28 mg/L and 72 hour ErC50 was 2.29 mg/L with the 95% confidence limits 1.64 ~ 3.20 mg/L.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Executive summary:

An alga growth inhibition study ofFMPBA was conducted for a period of 72 hours. Based on the results  of the preliminary  test, the  definitive  test was  carried  out  at 5 concentrations  of 2, 4.5,  10.0,  22.4 and  50 mg/L  (nominal  concentration).  A concurrent control group was included in parallel. 3 replicates were included in the control and treatment groups.

The alga species used  in the test was Desmodesmus  subspicatus and the initial  cell concentration was 0.5x10 cell/mL.  Alga growth medium recommended by OECD was used. During the  72 hours  test  period, the  cell concentration  in  each flask was  determined  by manual cell counting by microscope at 24 hours, 48 hours and 72 hours after the start of the test. The  concentration  of test  item  was  determined  in  samples  of test  media  by  HPLC method.

The results showed that for the test solutions of 2, 4.5,  10.0,  22.4 and 50 mg/L, the determined  concentrations  in  fresh media were 93.0% ~ 97.4% of nominal  concentrations, and  the  determined   concentrations   in  old  media  were   83.7% ~ 95.2%  of  nominal concentrations.  The test concentrations  were satisfactorily  maintained  in  the range of 80 ~ 120% of nominal concentration. According  to the results  and based  on the nominal  concentrations,  the 72-hour  effect concentration  of average  specific  growth  rate  (ErCx) of and yield (EyCx)  of FMPBA to Desmodesmus subspicatus was calculated by Probit analysis (EPA Probit Analysis Program Used for Calculating LC/EC Values Version 1.5) and the results were as follows:

Test endpoints	EC10 and 95% confidence limits  (mg/L)		EC50 and 95% confidence limits (mg/L)
Average specific growth rate growth rate	ErC10: 4.236	1.917 ~6.369	ErC50: 11.675	8.152 ~ 16.838
Yield	EyC10: 2.169	1.752 ~ 2.561	EyC50: 5.350	4.771 ~ 5.983