Research in Action
Engineered Nanomaterials in the Environment
Nanomaterials are a class of small-scale substances which are less than 100 nanometers in size. Although naturally occurring nanomaterials exist, EPA research is focused on understanding engineered nanomaterials (ENMs), which are designed with very specific properties. ENMs are intentionally produced via certain chemical or physical processes such as self-assembly from atoms and molecules, or milling from their macro-scale counterparts.
Because of the expected increase of nanotechnology applications, it is important for EPA to understand what happens to nanomaterials in the environment. Due to their novel size, ENMs often possess chemical, biological, and physical properties that larger particles don’t have, allowing ENMs to be used in thousands of products such as paints, fabrics, cosmetics, sunscreens, electronics, and automotive and construction products. ENMs used in industrial or environmental applications may be released into the environment during various phases of their life cycles including manufacturing, delivery, use, and disposal.
ENMs that find their way into solid waste, wastewater effluents, direct discharge, or accidental spillage may be transported to aquatic systems by wind or rainwater runoff. They can also be released from plastic composites via weathering processes, such as abrasion and sunlight-induced degradation.
The transformation and transport of ENMs in the environment largely depends on their surface chemistry and particle size, as well as biological and abiotic processes that occur in air, water, sediment and other environmental media. Because ENMs can exist as individual particles or clustered in groups associated with natural organic matter and sediments, they may remain suspended in air and water for long periods of time and be transported over greater distances than larger particles of the same material.
EPA scientists are developing new methods for detecting nanomaterials in the environment and conducting research to quantify and understand how nanomaterials move in the environment throughout their lifecycle. These data will assist health and ecological researchers determine the potential of ENMs to cause adverse health or environmental effects. Current research suggests the release of carbon nanotubes and metal nanoparticles from polymers and coatings may be a critical exposure pathway to both ecosystems and humans.
Characterization on a life cycle basis is challenging because nanotechnology is such a new field of study. Finding adequate data to model the potential fate and effects of releases of nanomaterials into the environment can be difficult. Much of the data must be estimated since many nanomaterials are not yet in full production for use in consumer products.
EPA scientists are collaborating on nanotechnology research with scientists from other federal agencies through the National Nanotechnology Initiative. This interagency organization brings together scientists from 25 federal agencies who are conducting nanomaterial-related research.
Results and Impact
EPA research results are anticipated to provide information for the development of mathematical models that can predict how ENMs move in the environment and through which pathways humans and ecosystems may be exposed.
Methods, models, and data developed by EPA scientists and other researchers involved in the National Nanotechnology Initiative will be used to assess the potential exposure and risk of nanomaterials by answering questions such as:
- Which nanomaterials are most likely to result in environmental exposures?
- What particular nanomaterial properties may raise toxicity concerns? Are nanomaterials with these properties likely to be in the environment or biological systems at concentrations of concern? What does this mean for risk?
- If nanomaterials are present at levels that may pose risk, can nanomaterial properties be changed to reduce exposure, leading to “greener” products?
Technical Team: Dermont Bouchard and Richard Zepp