Derivation of a chronic reference concentration for decalin.

Area of Science:

• Environmental toxicology
• Occupational health
• Chemical risk assessment

Background:

• Decalin is a naturally occurring and combustion-derived chemical found in crude oil.
• Commercial use of decalin as a solvent for oils and fats leads to widespread environmental and consumer product exposure.
• Currently, no established inhalation toxicity value exists for decalin, necessitating risk assessment research.

Purpose of the Study:

• To derive a chronic reference concentration (RfC) for decalin through inhalation toxicity studies.
• To address the lack of quantitative toxicity data for decalin exposure.
• To inform public health and environmental safety guidelines.

Main Methods:

• A weight-of-evidence approach was used to review inhalation toxicity studies.
• A 2-year mouse inhalation study was selected as the critical study.
• Benchmark dose modeling was applied to identify key adverse effects and derive a point of departure (BMDL10).

Main Results:

• Hepatic necrosis, syncytial alteration, eosinophilic focus, and erythrophagocytosis were identified as key adverse effects.
• A BMDL10 of 44 mg/m³ was modeled for syncytial alteration, the most sensitive effect.
• A chronic RfC of 0.08 mg/m³ was calculated using the BMDL10 and uncertainty factors.

Conclusions:

• The derived chronic RfC of 0.08 mg/m³ provides a critical inhalation toxicity value for decalin.
• Further research is recommended to fully characterize decalin's chronic inhalation toxicity.
• This study provides a foundation for refining decalin toxicity assessments and risk management strategies.