Confronting unknown planetary boundary threats from chemical pollution

Area of Science:

• Environmental Science
• Toxicology
• Planetary Health

Background:

• The concept of planetary boundaries defines a safe operating space for humanity.
• The 'chemical pollution' boundary lacks a clear, unified definition.
• Existing frameworks do not fully address the complexity of chemical impacts on Earth systems.

Purpose of the Study:

• To redefine the concept of chemical pollution within the planetary boundaries framework.
• To identify criteria for assessing chemical pollution as a planetary boundary threat.
• To propose a proactive strategy for identifying hazardous chemicals.

Main Methods:

• Analysis of the 'chemical pollution' planetary boundary definition.
• Development of three essential conditions for a chemical to pose a planetary boundary threat.
• Exploration of chemical identification and hazard assessment approaches.

Main Results:

• Chemical pollution is not a single boundary but encompasses multiple Earth system processes.
• Three specific conditions determine if a chemical poses a planetary boundary threat.
• A proactive hazard identification strategy is outlined, considering chemical transport and reversibility.

Conclusions:

• A revised understanding of chemical pollution's role in planetary boundaries is necessary.
• The proposed conditions and strategy can guide future environmental risk assessments.
• Addressing chemical pollution requires a multifaceted approach focused on hazard identification and prevention.