1-[(2,4-dinitrophenyl)azo]-2-naphthol

Endpoint summary

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1973

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Other substances present in the test material might have contributed to the observed effects

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 407 (Repeated Dose 28-Day Oral Toxicity Study in Rodents)

GLP compliance:

no

Species:

rat

Strain:

Wistar

Sex:

male/female

Route of administration:

oral: feed

Duration of treatment / exposure:

32 days

Frequency of treatment:

daily in diet

Remarks:

Doses / Concentrations:
0.2% (w/w) = 2,000ppm
Basis:
nominal in diet

Remarks:

Doses / Concentrations:
1.0% (w/w) = 10,000 ppm
Basis:
nominal in diet

Remarks:

Doses / Concentrations:
2.5% (w/w) = 25,000ppm
Basis:
nominal in diet

No. of animals per sex per dose:

10

Control animals:

yes, plain diet

Dose descriptor:

NOAEL

Effect level:

<= 10 000 mg/kg diet

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: Overall behavior and body weight

Dose descriptor:

NOAEL

Effect level:

< 2 000 mg/kg diet

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: Changes in blood samples

Remarks on result:

not determinable

Remarks:

no NOAEL identified

Critical effects observed:

not specified

Executive summary:

Ten male and ten female SPF-Wistar rats per group were exposed to C.I. Pigment Orange 5 in the diet for 32 days at three concentrations of 2.5%, 1% and 0.2%.

 

At the highest test concentration (2.5%) 7 male and 3 female rats died with the signs of severe weight loss. The general behavior of rats at 1 and 0.2% was not affected. The body weight gain was linked with a dose-dependence to the test substance. Only female rats at 0.2% concentration of test substance in the diet was not affected.

 

Tests of blood samples showed lower hemoglobin level, decrease in erythrocyte and leukocyte increase at all three test concentrations compared with the control group. The urine examination revealed no pathological findings.

 

The histological examination of the organs did not show any clear signs of changes related to the experiment. Only the iron content in the spleen appears to be slightly elevated in all experimental groups compared to the control group. The effect was not dose related.

Infiltrates of lymphocytes in liver and kidney are to be interpreted as non-specific response to unspecified identifiable stimulus and was not dose related.

The macroscopic and microscopic examination of the organs of the rats showed a remarkable weight loss of the animals at the highest test exposure concentration (2.5%) and a small increase of the iron content in the spleen of all animals.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

NOAEL

100 mg/kg bw/day

Study duration:

subacute

Species:

rat

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Justification for selection of repeated dose toxicity via oral route - systemic effects endpoint:
0.2% Lowest LOAEC in feed study with rats (estimated daily dose: 100 mg/kg b.w.)

Repeated dose toxicity: via oral route - systemic effects (target organ) cardiovascular / hematological: spleen

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