Issues in assessing environmental exposures to manufactured nanomaterials

Area of Science:

• Environmental Science
• Nanotechnology
• Colloid Science

Background:

• Manufactured nanomaterials (MNs) are commercial products with dimensions between 10⁻⁹ m and 10⁻⁷ m.
• Their size distinguishes them from molecular species and bulk matter, affecting settling and diffusion in environmental media.

Purpose of the Study:

• To review the environmental fate and transport of MNs in atmospheric and aquatic systems.
• To highlight the need for kinetic approaches in modeling MN intermedium transport.

Main Methods:

• Review of existing literature on MN environmental behavior.
• Examination of colloidal particle suspension stability theories (e.g., DLVO theory).

Main Results:

• MNs may have an atmospheric residence time of 10-20 days if significant emissions occur.
• Larger atmospheric MN aggregates (10⁻⁷ m to 10⁻⁶ m) are more mobile but less likely to deposit in the respiratory system.
• Current aquatic exposure models may require more sophisticated approaches beyond basic DLVO theory.

Conclusions:

• Kinetic modeling is crucial for understanding MN transport between environmental compartments.
• Advanced concepts like Critical Coagulation Concentrations and Critical Zeta Potentials are valuable for aquatic exposure assessments.