Mono-, and di-(sec-hexadecyl)naphthalene

Endpoint summary

Description of key information

Repeated Dose Oral 90d-NOAEL=500ppm (~34 mg/kg/day) for rats (equivalent or similar to OECD TG 408)
Repeated Dose Dermal 90d NAOEL-125 mg/kg/day for rats (equivalent or similar to OECD TG 411)
Repeated Dose Inhalation 90d-Testing not required based on Column 2 Annex IX.

Key value for chemical safety assessment

Toxic effect type:

dose-dependent

Additional information

Dermal: The study substance is expected to have a low order of repeated dose toxicity by the dermal route of exposure. Testing was performed in a manner similar or equivalent to currently established OECD guidelines. Following 90 days of dermal exposure, the NOAEL for rats was determined to be 125 mg/kg/day. Statistically significant changes in serum chemistry parameters for males and females and changes in relative kidney weights in males were observed at the next highest dose of 500mg/kg/day. However, these limited effects are not indicative of significant toxicity and occur at doses above the guidance values for classification. 

 

Oral: The study substance is expected to have a low order of repeated dose toxicity by the oral route of exposure. Testing was performed in a manner similar or equivalent to currently established OECD guidelines. Following 90d of oral exposure, the NOAEL for rats was determined to be 500ppm (34.6-38.4 mg/kg bw/day). Effects on organ weights were observed at the next highest dose of 5000ppm (340-380 mg/kg/day) and were limited to increases in the absolute and/or relative weight of the kidney (both sexes) and of the adrenals and liver (females). However, there was no evidence of organ dysfunction (including no abnormal histopathology) at any dose. Overall, the limited effects observed were not indicative of significant toxicity and occurred at doses above the guidance values for classification.

 

Inhalation: In accordance with Column 2 of REACH Annex IX, repeated dose toxicity testing via the inhalation route is not necessary for the study substance as this exposure route is not the most appropriate route of administration, having regard to the likely route of human exposure. 

Justification for classification or non-classification

The limited effects observed following oral and dermal administration of the study substance were not indicative of significant toxicity and occurred at doses above the guidance values for classification. Therefore, these findings do not warrant classification of the study substance for target organ toxicity (repeated exposure) under the new Regulation (EC) 1272/2008 on classification, labeling, and packaging of substances and mixtures (CLP), under the Directive 67/518/EEC for dangerous substances and Directive 1999/45/EC for preparations, or under the Globally Harmonized System of Classification and Labelling of Chemicals (GHS).