Subchronic and developmental toxicity of aromatic extracts

Area of Science:

• Petroleum chemistry and toxicology
• Environmental health and safety
• Risk assessment of industrial chemicals

Background:

• Aromatic extracts (AEs), including distillate AEs (DAEs) and residual AEs (RAEs), are complex petroleum streams.
• DAEs often contain carcinogenic polycyclic aromatic compounds (PACs), while RAEs have lower concentrations.
• PACs in refinery streams are known to cause adverse effects in toxicity studies.

Purpose of the Study:

• To evaluate the toxicity of Aromatic Extracts (AEs), focusing on Distillate AEs (DAEs) and Residual AEs (RAEs).
• To assess the risks associated with Polycyclic Aromatic Compounds (PACs) in petroleum streams.
• To determine No Observed Effect Levels (NOELs) and Predicted Dose-Responses (PDR10s) for dermal and developmental toxicity.

Main Methods:

• Conducted a 13-week dermal toxicity study on light paraffinic DAE.
• Performed developmental toxicity studies on paraffinic DAEs and RAEs.
• Utilized in vivo micronucleus tests to assess genotoxicity of DAEs, RAEs, and other petroleum substances.

Main Results:

• Light paraffinic DAE showed dose-related effects with a NOEL <5 mg/kg/d; PDR10s ranged from 25-78 mg/kg/d.
• Developmental toxicity NOAEL for light paraffinic DAE was 5 mg/kg/d, with effects linked to maternal toxicity.
• RAEs demonstrated higher NOAELs (500 mg/kg for 90-day, 2000 mg/kg for developmental toxicity).
• Genotoxicity tests were largely negative, with a marginal positive result for light paraffinic DAE.

Conclusions:

• AEs, particularly DAEs, exhibit varying toxicity profiles influenced by PAC content.
• Reproductive toxicity is not a primary concern for AEs based on current data.
• Most DAEs are unlikely to cause in vivo chromosomal damage, but careful risk assessment is warranted.