2-({1-[(2-methoxyphenyl)amino]-1,3-dioxobutan-2-yl}diazenyl)benzoic 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

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 201 (Alga, Growth Inhibition Test)

Test guideline 2

Qualifier:

according to guideline

Guideline:

EPA OPPTS 850.5400 (Algal Toxicity, Tiers I and II) (January 2012)

Test guideline 3

Qualifier:

according to guideline

Guideline:

EU Method C.3 (Algal Inhibition test)

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

2-(2-{1-[(2-methoxyphenyl)carbamoyl]-2-oxopropyl}diazen-1-yl)benzoic acid

EC Number:

683-287-0

Cas Number:

877670-90-1

Molecular formula:

C18H17N3O5

IUPAC Name:

2-(2-{1-[(2-methoxyphenyl)carbamoyl]-2-oxopropyl}diazen-1-yl)benzoic acid

Test organisms

Test organisms (species):

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

Study design

Test type:

semi-static

Limit test:

yes

Total exposure duration:

72 h

Test conditions

Test temperature:

23.8-24-6°C

pH:

7.02-7.36 (start) 7.32-8.41 (end)

Reference substance (positive control):

yes

Remarks:

Potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

2.58 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

biomass

Remarks on result:

other: 2.21-3.00

Effect concentrations 2

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

11.87 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

growth rate

Remarks on result:

other: 7.24-19.48

Effect concentrations 3

Duration:

72 h

Dose descriptor:

EC50

Effect conc.:

2.52 mg/L

Nominal / measured:

meas. (arithm. mean)

Conc. based on:

test mat.

Basis for effect:

other: Yield

Remarks on result:

other: 2.11-3.00

Effect concentrations 4

Duration:

72 h

Dose descriptor:

NOEC

Effect conc.:

1.35 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

other: Biomass, Growth rate and Yield

Effect concentrations 5

Duration:

72 h

Dose descriptor:

LOEC

Effect conc.:

2.81 mg/L

Nominal / measured:

meas. (not specified)

Conc. based on:

test mat.

Basis for effect:

other: Biomass, Growth rate and Yield

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

In this 72-h algal growth inhibition test on Pseudokirchneriella subcapitata with
ANTHRANILIC ACID-AAOA, the 72-h EC50 based on growth rate was
determined as 11.87 mg/L. This EC50 value is higher than the solubility of the test
item in the test media. Yield was the most sensitive parameter with an 72-h EC50
of 2.52 mg/L. The overall NOEC was determined to be 1.35 mg/L. The test item
solutions were slightly coloured and there was a minor absorption at one of the
chlorophyll wavelengths, this could have influenced the growth inhibition,
however the EC50 was above the maximum solubility of the test item.

Executive summary:

The effect of ANTHRANILIC ACID-AAOA test item was assessed on algal growth

using the unicellular green alga Pseudokirchneriella subcapitata (Selenastrum

capricornutum), over an exposure period of 72 hours.

The following concentrations were used in the main study (S.S.=Stock Solution):

S.S./16; S.S./8; S.S./4; S.S./2 and S.S./1. The corresponding measured mean test item

concentrations were: 0.31; 0.62; 1.35; 2.81 and 6.03 mg/L.

The test design included three replicates at each test concentration and six replicates

for the untreated control. At the start of the study the alga cell number was 104 cells/mL in

all of the test cultures.

The observed inhibitions in the definitive test could have been related to the coloured test

material and light absorption, therefore the following additional measurements were

preformed:

The test solutions were formulated again by the same method as during the definitive

test. Thereafter the light absorptions of these test solutions were measured

photometrically. The light adsorption measurements were performed in the range of

350-700 nm, because the absorption maximum of the Chlorophyll A is about 430 and

660 nm and the absorption maximum of Chlorophyll B is about 450 and 640 nm.

The maximum light adsorption of the test item was at ~380 nm in the test solutions.

There was no significant absorption at 450 to 660 nm, but there was some adsorption

at 430 nm.

The light intensity (8127 lux) was in the acceptable range during the definitive test.

In this 72-h algal growth inhibition test on Pseudokirchneriella subcapitata with

ANTHRANILIC ACID-AAOA, the 72-h EC50 based on growth rate was

determined as 11.87 mg/L. This EC50 value is higher than the solubility of the test

item in the test media. Yield was the most sensitive parameter with an 72-h EC50

of 2.52 mg/L. The overall NOEC was determined to be 1.35 mg/L. The test item

solutions were slightly coloured and there was a minor absorption at one of the

chlorophyll wavelengths, this could have influenced the growth inhibition,

however the EC50 was above the maximum solubility of the test item.