1-[(2-chloro-4-nitrophenyl)azo]-2-naphthol

Toxicity to microorganisms

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

activated sludge respiration inhibition testing

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Study period:

2006

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Read across to Pigment Red 3 and Pigment Orange 5 – these are other substances in the Monoazo Red consortium which is a structural analogue

Justification for type of information:

Category of Monoazo Red Pigments (C.I. PIGMENT RED 3, C.I. PIGMENT RED 4, C.I. PIGMENT ORANGE 5)
1. HYPOTHESIS FOR THE CATEGORY APPROACH
A very similar chemical structure is the basis for similar physical-chemical properties as very low solubility in water (but also in organic solvents and lipophilic matrices) and non-degradability which lead to inert behaviour and negligible bioavailability. See attached PR4_CSR.doc in Section 13 (1.1.1. Category Definition and its members - Category Hypothesis).
2. CATEGORY APPROACH JUSTIFICATION
Monoazo Red Pigments do not exert toxic effects to aquatic, terrestrial and sediment organisms as well as bacteria. See attached PR4_CSR.doc in Section 13 (1.1.1. Category Definition and its members - Category Justification).

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

not required

Vehicle:

no

Test organisms (species):

activated sludge, domestic

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

3 h

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Validity criteria fulfilled:

yes

Conclusions:

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

Reference 2

Endpoint:

activated sludge respiration inhibition testing

Type of information:

read-across based on grouping of substances (category approach)

Adequacy of study:

key study

Study period:

2007

Reliability:

1 (reliable without restriction)

Justification for type of information:

Category of Monoazo Red Pigments (C.I. PIGMENT RED 3, C.I. PIGMENT RED 4, C.I. PIGMENT ORANGE 5)
1. HYPOTHESIS FOR THE CATEGORY APPROACH
A very similar chemical structure is the basis for similar physical-chemical properties as very low solubility in water (but also in organic solvents and lipophilic matrices) and non-degradability which lead to inert behaviour and negligible bioavailability. See attached PR4_CSR.doc in Section 13 (1.1.1. Category Definition and its members - Category Hypothesis).
2. CATEGORY APPROACH JUSTIFICATION
Monoazo Red Pigments do not exert toxic effects to aquatic, terrestrial and sediment organisms as well as bacteria. See attached PR4_CSR.doc in Section 13 (1.1.1. Category Definition and its members - Category Justification).

Qualifier:

according to guideline

Guideline:

OECD Guideline 209 (Activated Sludge, Respiration Inhibition Test

GLP compliance:

yes (incl. QA statement)

Analytical monitoring:

not required

Vehicle:

no

Test organisms (species):

activated sludge, domestic

Test type:

static

Water media type:

freshwater

Limit test:

yes

Total exposure duration:

3 h

Duration:

3 h

Dose descriptor:

EC50

Effect conc.:

> 1 000 mg/L

Nominal / measured:

nominal

Conc. based on:

test mat.

Basis for effect:

inhibition of total respiration

Remarks:

respiration rate

Validity criteria fulfilled:

yes

Conclusions:

The test item is not toxic at concentrations <1000 mg/L to activated sludge from a municipal treatment plant

Description of key information

Neither C.I. Pigment Red 3 or C.I. Pigment Orange 5 are toxic at concentrations ≤ 1000 mg/L to activated sludge of a municipal sewage treatment plant.

Key value for chemical safety assessment

EC50 for microorganisms:

1 000 mg/L