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Administrative data

Description of key information

The acute toxicity of 1,2,3,4-tetrahydronaphthalene was found to be relatively low with an oral LD50 of 2860 mg/kg bw (male rats), a dermal LD50 of 16,800 mg/kg bw (male rabbits) and no mortalities within 8 hours inhalation of a saturated atmosphere (ca. 1800 mg/m³; male rats).
In man, the chemical is known to produce headache, nausea, vomiting, lacrimation, green-gray urine, and restlessness at high concentrations.

Key value for chemical safety assessment

Acute toxicity: via oral route

Endpoint conclusion
Dose descriptor:
LD50
2 860 mg/kg bw

Acute toxicity: via inhalation route

Endpoint conclusion
Dose descriptor:
LC50
1 800 mg/m³

Acute toxicity: via dermal route

Endpoint conclusion
Dose descriptor:
LD50
16 800 mg/kg bw

Additional information

Partly cited from SIAR for SIAM 19 (19-22 October 2004):

Studies in Animals

Inhalation

Smyth, Carpenter and Weil (1951) reported that six male rats tolerated exposure to saturated atmospheres of 1,2,3,4-tetrahydronaphthalene for eight hours without deaths. A vapor pressure of 34 Pa corresponds to a concentration of 1800 mg/m3. Union Carbide Corp. (1992) added the information that 8 hour exposures to mist, which was generated by aerating the compound while it was heated to 170 °C, were also tolerated without mortalities. Thus one may conclude from this limited study that the LC50 is > 1800 mg/m3. Dermal According to Smyth, Carpenter and Weil (1951) and Union Carbide Corp. (1992), the dermal LD50 of 1,2,3,4-tetrahydronaphthalene in male rabbits is approximately 16,800 mg/kg bw within 14 days post observation. After occlusive exposure of 5 animals each to doses of 12.6; 15.8 and 20.0 g/kgbw for 24 hours, the skin was erythematous, on subsequent examination it was necrotized and ultimately leathery and dry. Autopsy revealed pale livers and kidneys and congestion of the pancreas and intestines.

Oral

In a study with 10 malerats per dose group, the oral LD50 was approximately 2860 mg/kg bw (Smyth, Carpenter and Weil, 1951; Union Carbide Corp., 1992). The doses reported are 2000; 2520; 3160; 3980; 7950 mg/kg bw. Following the doses, the rats exhibited symptoms of sluggishness, prostration, and narcosis. The urine had a brownish coloration. A dose of 7950 mg/kg bw produced severe lung hemorrhage, congestion of the liver, paleness of the kidney with edema in some instances, opacity and adhesions of the intestines. Several of the livers were jaundiced after the administration of a dosage of 3980 mg/kg bw. This effect was not found at the higher level because of rapid death. Lower dosage levels produced similar symptoms of lesser intensity. Since from the other toxicity studies there is no evidence of significant differences in sensitivity between males and females, this study is considered to cover the SIDS endpoint sufficiently.

Studies in Humans

Experience with human exposure to 1,2,3,4-tetrahydronaphthalene was gathered mainly in the years after World War I, when 1,2,3,4-tetrahydronaphthalene was used as a substitute for turpentine. In general, the reliability of the data reported cannot be determined due to lack of documentation. Inhalation Koelsch (1926; insufficiently documented) reports that after occupational application of 1,2,3,4- tetrahydronaphthalene or staying in freshly varnished or waxed rooms, workers complained about headache, nausea, vomiting and irritation of mucous membranes and green-colored urine. In two painters who had been painting for three days with 1,2,3,4-tetrahydronaphthalene-containing varnishes in a poorly ventilated area dark green colored urine was observed as the main symptom beside intense irritation of mucous membranes, profuse lacrimation, headache, and stupor. Reversibility was complete within few days (Arnstein, 1922). After approximately 3 kg wax containing about 1.5 kg 1,2,3,4-tetrahydronaphthalene had been applied in a hospital room of approximately 540 m3 volume, children displayed green colored urine and a marked degree of restlessness. This restlessness was tentatively attributed to a direct effect of 1,2,3,4-tetrahydronaphthalene on the central nervous system without giving further details (Röckemann, 1922; insufficiently documented). Hospital patients on a ward whose floor was recently waxed with a tetralin-based polish and whose windows were closed due to cold weather experienced eye irritation, headache, nausea, diarrhea, and green urine (Badinand, Paufique and Rodier, 1947; insufficiently documented).

Dermal

No data available.

Conclusion

The acute toxicity of 1,2,3,4-tetrahydronaphthalene was found to be relatively low with an oral LD50 of 2,860 mg/kg bw (male rats), a dermal LD50 of 16,800 mg/kg bw (male rabbits) and no mortalities within 8 hours inhalation of a saturated atmosphere (ca. 1,800 mg/m3; male rats). In man, the chemical is known to produce headache, nausea, vomiting, lacrimation, green-gray urine, and restlessness at high concentrations

 

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Justification for classification or non-classification

Acute toxicity of tetrahydronaphthalene was low. Classification is not required.