N-(4-chloro-2,5-dimethoxyphenyl)-3-hydroxy-4-[(E)-2-[2-methoxy-5-(phenylcarbamoyl)phenyl]diazen-1-yl]naphthalene-2-carboxamide; N-(5-chloro-2-methylphenyl)-3-hydroxy-4-[(E)-2-[2-methoxy-5-(phenylcarbamoyl)phenyl]diazen-1-yl]naphthalene-2-carboxamide

Endpoint summary

Description of key information

Fish

PR184

The test was performed with GLP compliance and similar to OECD-guideline 203. Using a dispersion of the submission substance as test item (42.8% of submission substance), high concentrations far above water solubility could be tested avoiding formation of any precipitate.
Under the conditions of this test the LC50 of the test item after 96 hours was > 500 mg/L (214 mg/L submission substance) and the LC0 equal to 500 mg/L (214 mg/L submission substance), based on nominal concentrations, each.
As the test item contains a relevant amount of the submission substance, the test results are considered adequate to fulfill the endpoint requirements.

Aquatic Invertebrates

PR022

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

PR022 

In a daphnia magna reproduction test performed according to OECD 211 and compliant to GLP (reliability category 1) with semistatic test design (test medium renewal every 48 hours) no statistically significant effects were observed at the limit test item concentration of 30 mg/L (time weighted mean measured concentration). The following (no)effect concentrations (21 days) were determined:
LC50 (adult mortality) > 30 mg/L (TWA)
LOEC (reproduction, adult mortality, macroscopic effects) > 30 mg/L (TWA)
NOEC (reproduction, adult mortality, macroscopic effects) = 30 mg/L (TWA)
The validity criteria of the guideline were met.

PR112 

The test substance was tested in a daphnia magna reproduction test performed according to OECD 211 and compliant to GLP (reliability category 1). At the saturated solution of the test item with a nominal loading of 1.00 mg/L no biologically or statistically significant effects were determined. The No Observed Effect Loading (NOEL) and the Lowest Observed Effect Loading (LOEL) were assessed at:
NOEL: Saturated Solution (with the nominal loading of 1.00 mg/L)
LOEL: > Saturated Solution (with the nominal loading of 1.00 mg/L)
All effect values given are based on the saturated solution of the test item with the nominal loading of 1.00 mg/L.

Algae

PR022 

In a reliable study (reliability category 1) on green alga Selenastrum capricornutum growth inhibition (static, 72 hours, analytical verification of test item concentration) performed according to GLP the following growth rate related (no)effect concentrations were determined for the test item:
EC50 (72 hours) > 100 mg/L (97 mg/L geometric mean measured concentration);
NOEC (72 hours) = 3.2 mg/L (2.85 mg/L geometric mean measured concentration).
These values were determined in relation to the solvent control (100 mg/L HCO-40, equal concentration to treatment groups), as growth was significantly enhanced compared to the control without solvent.
Tested concentrations were far above water solubility of the test item (11.8 µg/L) and were achieved by use of hydrogenated castor oil (HCO-40) at equal weight as co-solvent. The strong red coloring of test solutions might have resulted in light absorption causing reduced growth of algae due to reduced effective illumination strength.
Thus, observed effects are to be regarded as not relevant because they are
1) most probably not due to intrinsic toxicity of the test item and
2) far above the true water solubility of the test item (NOEC is a factor of 270 above water solubility).
Thus, the NOEC is not appropriate to derive a PNEC, as light absorption due to the coloring of the test item is not relevant in the range of actual water solubility.
The test item is to be regarded as non-toxic to freshwater green algae.

PR122

In this study the test item was found not to inhibit the freshwater green algae Desmodesmus subspicatus after 72 h at the saturated solution (prepared with 1 mg/L). All effect levels are given based on the nominal concentration of Pigment Red 112.

Microorganisms

PR112 

A Respiration Inhibition Test with activated sludge according to OECD Guideline No. 209 was performed compliant to GLP with the submission substance (reliability category 1). TThe test was performed under static conditions with the nominal limit concentration of 1000 mg/L. The respiration rates of control, reference and test item concentrations were measured after a contact time of three hours, and the inhibitory effects of the test and reference concentrations were determined in comparison to the control respiration rates. No inhibition was observed at the tested limit concentration.

Validity criteria of the test guideline were fulfilled.

The test item is not toxic at concentrations >= 1000 mg/L to activated sludge of a municipal sewage treatment plant.