Toluene: correlation between occupational exposure limits and biological exposure indices

Area of Science:

• Occupational Health
• Toxicology
• Biomonitoring

Background:

• Occupational hygiene and medicine rely on threshold limit values (TLVs) and biological exposure indices (BEIs) to manage worker chemical exposure.
• Establishing new toluene exposure limits necessitates a review of appropriate biological indicators.
• Toluene exposure is linked to adverse health effects, including miscarriage, highlighting the need for effective monitoring.

Purpose of the Study:

• To analyze the scientific data influencing the reduction of occupational exposure limits for toluene.
• To evaluate the suitability of ortho-cresol as a biological indicator for toluene exposure.
• To address the delay in adopting updated biological monitoring practices in Brazil compared to international standards.

Main Methods:

• Comprehensive literature review.
• Analysis of factors contributing to the lowering of occupational exposure limits for toluene.
• Evaluation of ortho-cresol as a biomarker for toluene.

Main Results:

• The scientific literature supports the lowering of occupational exposure limits for toluene due to critical health effects.
• Urinary ortho-cresol has been identified as a suitable biomarker for toluene exposure since 2007.
• Brazil's discussion on changing biological indicators for toluene began significantly later than international adoption.

Conclusions:

• There is strong scientific evidence supporting the utility of ortho-cresol as a biological indicator for toluene.
• The primary challenge is the lack of an implemented monitoring system to align with current legislation and scientific understanding.
• Urgent implementation of biomonitoring systems using ortho-cresol is required to ensure worker safety and regulatory compliance.