Research Investigates Human Health Effects of Nanomaterials
Extremely small nanomaterials can exhibit unique characteristics that are leading scientists to question what implications they may have for our health.
Nanotechnology is a relatively new science and, as a result, the health implications associated with engineered nanomaterials have not been determined. Much of today's information on health effects is from decades of understanding the effects from natural or incidentally formed nano-sized materials such as ultrafine particles from dust or incomplete combustion.
Research is needed to determine whether exposure to manufactured nanomaterials can lead to adverse effects to the heart, lungs, skin; alter reproductive performance; or contribute to cancer.
The scientific challenge to understand the potential human health risk of manufactured nanomaterials is significant. There are already many types of manufactured nanomaterials commercially available or are under development. In many cases, the same type of nanomaterial can be produced by several different processes, giving rise to a number of versions that may require separate assessments.
Other scientific issues include:
- Nanomaterials may enter the body by routes not typically found with other chemicals because of their small size.
- If nanomaterials of certain sizes are able to enter the body, they may pass through cell membranes or cross the blood-brain barrier because of their small size. In some cases this is a beneficial characteristic when used for drug delivery and disease treatments. This characteristic could also result in unintended impacts for manufactured nanomaterials not designed for disease therapies.
- Nanomaterials may interact with environmental media and pollutants to produce by-products that may have the potential to cause health effects.
As with all toxicological assessment, it will be necessary to develop information on:
- Route of exposure (inhalation, oral, or dermal) that carries the greatest risk
- Physical and chemical characterization of nanomaterials
- Dose–response relationship of manufactured nanomaterials and toxicity
EPA Researchers are studying nanomaterials to understand the potential unintended consequences from accidental or intentional exposure to humans. This information will be used to prevent or minimize exposure during manufacturing, use, and disposal of products made with nanomaterials. The program is designed to develop scientific methods and tools for determining the potential risks.
The research program has a three-pronged approach for assessing the potential toxicity of nanomaterials:
- Identify and characterize the physical and chemical properties of manufactured nanomaterials
- Identify alternative testing methods and approaches to predict toxicity in humans which includes identification of biomarkers of nanomaterial exposure and/or toxicity
- Assess the toxicity of nanomaterials in animals. These studies will include research to identify host susceptibility and sensitivity facts that may influence toxicity.
Nanoparticles can generate local toxic effects as well as systemic (entire body) effects. Toxicological assessment of engineered nanomaterials will consider both local and systemic toxic responses.
Previous research on particles has shown that not all individuals respond in the same way or to the same degree. Individual and population susceptibility factors can influence the magnitude of toxicity, deposition, fate, and persistence of nanomaterials.
The impact of susceptibility factors on manufactured nanomaterials is not known and provides the opportunity for EPA scientists to identify what susceptibility factors impact the toxicity of engineered nanomaterials.
Application and Impact:
The results of EPA's health effects research will inform safety assessments of manufactured nanomaterials and determine the potential adverse effects of products that contain them.
Nanotechnology science is being used to:
- Recommend safe exposure levels that would protect susceptible subpopulations
- Investigate occupational safety and health issues associated with aerosolized nanoparticles
- Investigate workplace exposure monitoring and protocols
- Develop personal protection for activities involving manufactured nanomaterials in the workplace
William Boyes (firstname.lastname@example.org), National Health and Environmental Effects Research Laboratory, EPA's Office of Research and Development, 919-541-7538.