1-benzyl-5-phenylbarbituric acid

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:

2018-05-14 - 2018-05-18

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 (Alga, Growth Inhibition Test)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

1-benzyl-5-phenylbarbituric acid

EC Number:

276-940-2

EC Name:

1-benzyl-5-phenylbarbituric acid

Cas Number:

72846-00-5

Molecular formula:

C17H14N2O3

IUPAC Name:

1-benzyl-5-phenylpyrimidine-2,4,6(1H,3H,5H)-trione

Test material form:

solid: particulate/powder

Specific details on test material used for the study:

Molecular Formula:
C17H14N2O3
Molecular Weight:
294.3
Characteristics (Physical Appearance):
White powder
CAS No.:
72846-00-5
Batch Number:
170240
Purity:
99.5%

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

The concentration verification of the test solution were carried out at 0 hour and 72 hours after initiation of exposure for the concentration of 50 mg/L (Maximum Soluble Concentration).

Test solutions

Vehicle:

no

Details on test solutions:

35 mg of 1-Benzyl-5-Phenylbarbituric acid (BPBA) was suspended in OECD media to prepare a stock solution of a final volume of 700 ml, with a nominal concentration of 50 mg/L and this solution was sonicate for 30 minutes. This stock solution was then divided into test containers.

Test organisms

Test organisms (species):

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

Details on test organisms:

Test species:
Unicellular green alga, Pseudokirchneriella subcapitata (Selenastrum capricornutum)
Justification for selection of species:
Species recommended by OECD Guideline No. 201.
Strain:
ATCC-22662
Source:
Procured from American Type Culture Collection (ATCC) and maintained at INTOX PVT. LTD.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

72 h

Test conditions

Test temperature:

Incubator maintained at 25.4 to 25.5 0C.

pH:

7.58 to 8.45 (0 hour to 72 hours)

Nominal and measured concentrations:

nominal 50 mg/l

Details on test conditions:

Test Condition:
Static
Culture Medium:
OECD Medium
Test Flasks:
The cultures were maintained and tested in conical flasks with capacity 250 ml each containing 100 ml OECD Medium.
Culture Apparatus:
Incubator maintained at 25.4 to 25.5 0C.
Illumination:
A continuous uniform illumination of 4650 to 5890 Lux, cool white light during the test.
pH of the test solutions:
7.58 to 8.45 (0 hour to 72 hours)
Exposure period:
72 hours
Initial Cell Concentration:
25000 cells/mL

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 50 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

growth rate

Effect concentrations 2

Key result

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

> 50 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

biomass

Results with reference substance (positive control):

The ErC50 (72 hours) of reference item, Potassium dichromate in fresh water unicellular green algae Pseudokirchneriella subcapitata is estimated to be 0.72 mg/L with fiducial limits between 0.43 to 1.13 mg/L at 95% confidence level.
The EyC50 (72 hours) of reference item, Potassium dichromate in fresh water unicellular green algae Pseudokirchneriella subcapitata is estimated to be 0.45 mg/L with fiducial limits between 0.39 to 0.52 mg/L at 95% confidence level.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

Growth inhibition Test of 1-Benzyl-5-Phenylbarbituric acid (BPBA) in fresh water green alga -Pseudokirchneriella subcapitata (Selenastrum capricornutum) was performed in compliance with the OECD Guideline for Testing of Chemicals, No. 201, ‘Freshwater Alga and Cyanobacteria, Growth Inhibition Test’, Section 2, adopted by the Council on 23 March 2006 and Annex 5 corrected: 28 July 2011.
The ErC50 (72 hours) value of 1-Benzyl-5-Phenylbarbituric acid (BPBA) in fresh water unicellular green alga - Pseudokirchneriella subcapitata is estimated to be greater than 100 mg/L (Maximum Soluble Concentration).
The EyC50 (72 hours) value of 1-Benzyl-5-Phenylbarbituric acid (BPBA) in fresh water unicellular green alga - Pseudokirchneriella subcapitata is estimated to be greater than 50 mg/L (Maximum Soluble Concentration).

Executive summary:

Growth inhibition Test of 1-Benzyl-5-Phenylbarbituric acid (BPBA) in fresh water green alga -Pseudokirchneriella subcapitata (Selenastrum capricornutum) was performed in compliance with the OECD Guideline for Testing of Chemicals, No. 201, ‘Freshwater Alga and Cyanobacteria, Growth Inhibition Test’, Section 2, adopted by the Council on 23 March 2006 and Annex 5 corrected: 28 July 2011.

1-Benzyl-5-Phenylbarbituric acid (BPBA) was tested for its possible inhibitory effect on growth of alga, Pseudokirchneriella subcapitata. Exponentially growing cultures of the algae were exposed to test item at concentration of 50 mg/L (Maximum Soluble Concentration) for a period of 72 hours, along with a concurrent blank control group. Potassium dichromate, used as a reference item, was also concurrently tested at concentrations of 0.4, 0.8 and 1.6 mg/L. The cell concentration, i.e. the number of cells per ml, for all the concentrations, was counted at 24, 48 and 72 hours of the exposure by counting them under microscope in a haemocytometer counting chamber and the inhibition of growth in relation to the control culture was determined.

Percent inhibition of growth rate in fresh water unicellular green alga, Pseudokirchneriella subcapitata at 72 hours, was 1.28 recorded at the concentration of 50 mg/L. In reference item group percent inhibition of growth rates in fresh water unicellular green alga, Pseudokirchneriella subcapitata at 72 hours, were 19.85, 46.33 and 98.15 recorded at the concentrations of 0.4, 0.8 and 1.6 mg/L respectively.

Percent inhibition in yield in fresh water unicellular green alga, Pseudokirchneriella subcapitata at 72 hours, was 3.77 recorded at the concentration of 50 mg/L. In reference item group percent yield in fresh water unicellular green alga, Pseudokirchneriella subcapitata at 72 hours was 45.61, 77.62 and 99.58 recorded at the concentrations of 0.4, 0.8 and 1.6 mg/L respectively.

The ErC50 (72 hours) value of 1-Benzyl-5-Phenylbarbituric acid (BPBA) in fresh water unicellular green alga - Pseudokirchneriella subcapitata is estimated to be greater than 50 mg/L (Maximum Soluble Concentration).

The EyC50 (72 hours) value of 1-Benzyl-5-Phenylbarbituric acid (BPBA) in fresh water unicellular green alga - Pseudokirchneriella subcapitata is estimated to be greater than 50 mg/L (Maximum Soluble Concentration).