Engineered Nanomaterials as Emerging Contaminants in Water - Nanotechnologies for Water Environment Applications - page 561

1. Develop instruments to assess exposure to engineered NMs in air and water,

within the next 3-10 years. For example:
• Develop “smart sensors” that indicate potential harm

• Develop a universal aerosol sampler for airborne nanostructure materials

• Instruments to monitor waterborne engineered NMs

2. Develop and validate methods to evaluate the toxicity of engineered NMs, within

the next 5-15 years;

3. Develop models for predicting the potential impact of engineered NMs on the

environment and human health, within the next 10 years;

4. Develop robust systems for evaluating the health and environmental impact of

engineered NMs over their entire life, within the next 5 years; and

5. Develop strategic programs that enable relevant risk-focused research, within the

next 12 months.

This chapter addresses parts of these grand challenges developed for a
precautionary approach to all aspects of nanotechnology by describing conditions that
may give rise to NMs in aquatic systems as emerging contaminants of concern.
Fundamental questions regarding engineered NMs as emerging contaminants in water
are addressed in this chapter:
•

Are engineered NMs critically different from natural NMs which have been
studied for decades, and can the properties that make natural NMs quasi-stable
(i.e., non-aggregating) in water be applied to understand the fate of engineered
NMs in water?

• What are the likely sources of engineered NMs into aquatic systems?

• What types of analytical methods are needed for detecting and tracking

engineered NMs in aquatic systems?

• Can existing fate and transport models be used to represent processes and predict

the movement of engineered NMs within aquatic systems?

16.3 Classification of Nanomaterials

NMs are defined as having one dimension less than 100 nm and can be divided
into three categories: (a) natural NMs, (b) incidental NMs (i.e., automobile combustion
products), or (c) engineered NMs with unique mechanical, optical, magnetic or
electrical properties. Natural NMs include clays, metal oxides (e.g., iron (hydr)oxides),
other low solubility metals (e.g., sulfides, phosphates) and organic colloids. Incidental
NMs are the unintended result of human activity including combustion particles,
industrial processes (e.g., mechanical wear), vehicles, construction and air pollution
particles, which include inorganic NMs and carbonaceous NMs (e.g., soot-like).