Nano-materials: Environmental and Health Impacts

Chem Eng Progress: 104 (12), 37-40, 2008.

Some Facts

• More than 500 consumer products containing nano-materials are on the market;• Some examples: pesticides, genetically modified foods – uncertainties and concerns about health risks• Need more research on related environmental, health and safety (EHS) issues;• Need standard nomenclature on nanotechnology, standard reference materials for EHS testing, and standard methods and procedures for evaluating EHS impacts;

Some concerns

• Bad memories: CFC, PCB, asbestos, etc.• Unknowns: ZnO/TiO2 nanoparticles in sunscreens; some research, yet no unanimous conclusion on penetration, cytotoxicity;• Obtaining physiologically or environmentally relevant information for assessment is difficult; • Suspect: carbon nanotube (next asbestos ?) some data showed similarity on health effect between these two chemicals;

Regulations

•May be regulated under existing legislation: EPA, OSHA, FDA, Consumer Product Safety Commission CPSC; (for USA)• Example: EPA has laws: Toxic Substances Control Act (TSCT), Clean Air Act (CAA), Clean Water Act (CWA), etc; They released TSCT – inventory status of nanoscale substance – general approach; “molecular identity” – the deciding factor• EPA: need risk assessment (to environment and human) before action; to date, most work are on LC50;

Nanoscale

• Richard Feynman: “at the atomic level, we have new kinds of forces, new kinds of possibilities, new kinds of effects”• From microscale to nanoscale: increase in surface area/volume ratio (surface atom more active), improved delivery and transport properties in biomedical fields, appearance of quantum effect (e.g. size dependent optical property);• Any unforeseen effects? Toxicity?

Precautionary Approach

•EPA: current practice – categorizing nano-materials as their bulk counterparts; • Precautionary principle: If activity raises threats of harm to human and/or environment, precautionary measures should be taken.

• Uncertainty remains: Need more efforts!