4-[(2,5-dichlorophenyl)azo]-3-hydroxy-N-(2-methoxyphenyl)naphthalene-2-carboxamide

Short-term toxicity to aquatic invertebrates

Administrative data

Endpoint:

short-term toxicity to aquatic invertebrates

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 2000-12-13 to 2001-04-27

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study performed according to relevant guideline and compliant to GLP, well documented translation of original report (in Japanese)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2001

Report date:

2001

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 202 (Daphnia sp. Acute Immobilisation Test)

Deviations:

no

GLP compliance:

yes

Remarks:

The study was conducted in accordance with "Eco-toxicity test Standards" by Japanese Ministry of the Environment.

Test material

Test material information

Constituent 1

Reference substance name:

3-hydroxy-4-[(2-methyl-5-nitrophenyl)azo]-N-phenylnaphthalene-2-carboxamide

EC Number:

229-245-3

EC Name:

3-hydroxy-4-[(2-methyl-5-nitrophenyl)azo]-N-phenylnaphthalene-2-carboxamide

Cas Number:

6448-95-9

Molecular formula:

C24H18N4O4

IUPAC Name:

3-hydroxy-4-[(2-methyl-5-nitrophenyl)diazenyl]-N-phenyl-2-naphthamide

Test material form:

not specified

Details on test material:

Name of test material (as cited in study report): Acute Immobilization Test of ... on Water Fleas (Daphnia magna): C. I. Pigment Red 22 (abbreviated name: PR)
Analytical purity: Over 99%

Sampling and analysis

Analytical monitoring:

yes

Details on sampling:

Samplings were made at the time point of study initiation (0 hr) and termination (48 hr).

Test solutions

Vehicle:

yes

Details on test solutions:

After weighing of a necessary amount of test substance using an electronic balance, the same amount of hydrogenated castor oil (HCO-40) was added to the test substance as co-solvent and mixed well. Then, the solution was made up to the volume with dilution water and mixed with a stirrer for 30 minutes to prepare the test solution of the desired nominal concentration.
The prepared test solutions showed strong red color but no visible precipitate was observed. The solution of control and solvent control was observed to be clear and colorless without visible undissolved test substance.

Test organisms

Test organisms (species):

Daphnia magna

Details on test organisms:

Species: Water fleas
Scientific name: Daphnia magma
Supplier: National Institute for Environmental Studies, Japan
Date of receipt: October 28, 1996
Maintenance after received: Subculture
Acclimation: Acclimation period: December 28, 2000 - January 16, 2001
Mortality of parent daphnids during acclimation period was 0% and ephippia and presence of males were not observed.
Age: Juvenile within 24-hr of age

Condition for acclimation
Water: Dilution water
Loading: 100 daphnids per 5 L culturing water
Temperature: 20 +/- 1 deg C
Lighting: Indoor lighting, 16 hr light 18 hr dark
Feeding: Chlorella vulgaris (commercially available condensed chlorella liquid, trade name: raw chlorella-V12, manufacture: Chlorella Industry Co., Ltd.). The amount of organic carbon in 1% suspension was 1192 mg C/L (measured on December, 2000). The amount fed was determined based on this value. The measurement of the amount of organic carbon was contracted out to Koei Techno Company, Limited.
Feed amount: 0.1 - 0.2 mg C (total organic carbon) per daphnid per day.

Study design

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

48 h

Post exposure observation period:

No

Test conditions

Hardness:

Total hardness 63.1 mg/L

Test temperature:

Temperature: 20 +/- 1 deg C

pH:

8.0 to 8.1

Dissolved oxygen:

8.6 to 8.9 mg/L

Nominal and measured concentrations:

Nominal limit concentration: 100 mg/L;
Measured concentration test start: 100 mg/L;
Measured concentration test end (48 hours): 120 mg/L;
Geometric mean measured concentration: 110 mg/L.
The concentration of test substance in the control and solvent control were less than the quantification limit (0.06 mg/L).

Details on test conditions:

- Volume of test solution: 100 mL / vessel (glass beaker)
- Replication: 4 vessel / test group
- Number of organisms: 20 daphnids per test group (5 daphnids per vessel)
- Lighting: Indoor lightning, 16-hour light, 18-hour dark
- Feeding: None
- Dilution water: Tap water (Takarazuka city, Hyogo) was dechlorinated with charcoal filter and saturated with oxygen by aeration. Then the water was used as the dilution water after adjusting to the test temperature. The results of water quality measurement are shown in section "Any other information on materials and methods incl. tables". From the results of the water quality measurement and no observed abnormalities in organisms, it was judged that the dilution water can be used as culturing water in the bio-assays.
- Water bath: Thermostatic water bath for daphnid test
- Selection of test concentration: In a range-finding study conducted at the concentration of 10 mg/L and 100 mg/L (which was the maximum attainable homogeneous dispersion concentration), no immobilizations were observed among daphnids exposed to all the exposure levels. Based on these results, a limit test with 100 mg/L was chosen for the definitive study. As reference, a control group (dilution water only) and a solvent control group, in which co-solvent concentration was 100 mg/L (i.e. the same as for the exposure group) were allocated in the study.
- Test operation procedure: The prepared test solutions were dispensed to 4 vessels with 100 mL per each test concentration, and the vessels were placed in the thermostatic water bath. The initiation of exposure was defined as the time point at which daphnids were introduced to each vessel using glass pipette after measurement of temperature, dissolved oxygen level and pH of test solution. The pipetted aliquot of water was less than approximately 1% of the volume of test solution, which was used as guide. The observation of number of immobilized daphnids was made at 24 and 48 hours after the initiation of exposure. The daphnid was judged as immobilized when the daphnid was not able to swim within 15 seconds after gentle agitation of the test vessel (The swimming was defined that the daphnid was able to swim in water. Therefore, the daphnid crawling and moving along the bottom of the vessel was judged as immobilized in the study. As for the floating of daphnid on the surface, it was judged as immobilized in case that although the daphnid was able to swim after immersed in the water forcibly by water drops, came up to water surface again. And, it was not
judged as immobilized in case that the daphnid swam in water at least once in 15 seconds, even if its swim was not normal).
The temperature, dissolved oxygen and pH of test solution of all test groups were measured at the initiation and termination of exposure.

Reference substance (positive control):

yes

Remarks:

potassium dichromate

Results and discussion

Effect concentrations

Effect concentrations 1

Duration:

48 h

Dose descriptor:

EC50

Effect conc.:

> 110 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 2

Duration:

48 h

Dose descriptor:

NOEC

Effect conc.:

110 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Effect concentrations 3

Duration:

48 h

Dose descriptor:

LOEC

Effect conc.:

> 110 mg/L

Nominal / measured:

meas. (geom. mean)

Conc. based on:

test mat.

Basis for effect:

mobility

Details on results:

Since the immobilization rate and the rate of floating daphnid on the surface in both the control and solvent control group at 48 hours exposure were 0%, it was judged that the study was conducted under appropriate conditions.
No immobilization occurred in the treatment replicates.

Results with reference substance (positive control):

The median effective concentration (EC50) at 48 hr with the reference substance potassium dichromate (reagent grade, Lot No. ACQ2610, Wako Pure Chemical Industries) was 0.64 mg/L, which was comparable to the historical EC50 of 0.38 - 0.94 mg/L, n = 10) obtained at the testing facility since December, 1995.

Reported statistics and error estimates:

No statistical analysis was applied for the calculation of median effective concentration (EC50), since the study was conducted as a limit test at 100 mg/L.
The no-observed-effect concentration (NOEC) was defined as the highest concentration where no adverse effect on daphnids was observed, and the lowest
concentration producing 100% immobilization was defined as the lowest concentration (EC100) where all daphnids were observed immobilized.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

In a reliable 48-hours acute toxicity study on Daphnia magna performed according to OECD 202 and compliant to GLP (reliability category 1), the test item caused no immobilization at the applied limit concentration of nominal 100 mg/L (geometric mean measured concentration: 110 mg/L). No immobilization occured in the control and the solvent control (containing the amount of HCO-40 used in the treatment group). The following (no)effect concentrations were determined (geometric mean measured concentrations):
EC50 (48 h): > 110 mg/L
LOEC (48 h): > 110 mg/L
NOEC (48 h): 110 mg/L

Executive summary:

In a reliable 48-hours acute toxicity study on Daphnia magna performed according to OECD 202 and compliant to GLP (reliability category 1), the test item caused no immobilization at the applied limit concentration of nominal 100 mg/L (geometric mean measured concentration: 110 mg/L). Hydrogenated castor oil (HCO-40) was used at equal weight as co-solvent to achieve the limit concentration of the otherwise insoluble test item. No immobilization occured in the control and the solvent control (containing the amount of HCO-40 used in the treatment group). The following (no)effect concentrations were determined (geometric mean measured concentrations):

EC50 (48 h): > 110 mg/L

LOEC (48 h): > 110 mg/L

NOEC (48 h): 110 mg/L

The robust study summary is based on the translation of the original study report performed by the same company involved with performance of the test (Sumika TechnoService Corporation, Japan).