Technical Fact Sheet – Nanomaterials November 2017 TECHNICAL FACT SHEET – NANOMATERIALS At a Glance Introduction This fact sheet, developed by the U.S. Environmental Protection Diverse class of substances Agency (EPA) Federal Facilities Restoration and Reuse Office that have structural (FFRRO), provides a summary of nanomaterials (NMs), including their components smaller than 100 physical and chemical properties; potential environmental and health nanometers (nm) in at least impacts; existing federal and state guidelines; detection and treatment one dimension (Klaine and methods; and additional sources of information. This fact sheet is others 2008). Nanomaterials intended for use by site managers and other field personnel who may (NMs) include nanoparticles need to address or use NMs at cleanup sites or in drinking water (NPs), which are particles with supplies. at least two dimensions between approximately 1 and NMs are increasingly being used in a wide range of household, 100 nm. cosmetic and personal use, scientific, environmental, industrial and Have high surface area to medicinal applications. NMs may possess unique chemical, biological volume ratio and the number of and physical properties compared with larger particles of the same surface atoms and their material (Exhibit 1). NM research is a rapidly growing area; current arrangement determines the size research is focused on carbon-based, metal and metal oxides, quantum and properties of the NM. dots and nanosilver. Due to the diverse nature of NMs, this fact sheet presents a high-level summary for NMs in general with specific focus on Can be categorized into three the NMs of current research interest. types: natural UFPs, incidental NMs and engineered NMs. What are nanomaterials? Engineered NMs are used in a wide variety of applications, For purposes of this document, NMs are a diverse class of including environmental substances that have structural components smaller than 100 remediation, pollution sensors, nanometers (nm) in at least one dimension. NMs include photovoltaics, medical nanoparticles (NPs), which are particles with at least two dimensions imaging and drug delivery. between approximately 1 and 100 nm (Klaine and others 2008). EPA refers to nano-sized particles that are natural or aerosol as ultrafine The mobility of NMs depends on particles (UFPs). factors such as surface chemistry and particle size, and on NMs have high surface area to volume ratio and the number of biological and abiotic processes in surface atoms and their arrangement determines the size and the media. properties of the NM (Sarma and others 2015). May stay in suspension as As of 2014, more than 1,800 consumer products containing NMs are individual particles, on the market (Vance and others 2015). aggregate, dissolve or react with other materials. Disclaimer: The U.S. EPA prepared this fact sheet using the most recent Characterization and detection publicly-available scientific information; additional information can be obtained technologies include from the source documents. This fact sheet is not intended to be used as a primary source of information and is not intended, nor can it be relied upon, to differential mobility analyzers, create any rights enforceable by any party in litigation with the United States. mass spectrometry and Mention of trade names or commercial products does not constitute endorsement scanning electron microscopy. or recommendation for use. United States Office of Land and Emergency EPA 505-F-17-002 Environmental Protection Agency Management (5106P) November 2017 1 Technical Fact Sheet – Nanomaterials NMs and UFPs can be categorized into three types according to their source: . Natural UFPs include combustion products, viruses and sea spray. Incidental NMs are generated by anthropogenic processes and include diesel exhaust, welding fumes and industrial effluents. Engineered NMs are designed with very specific properties and are made through chemical and/or physical processes (Exhibit 1). Exhibit 1: Properties and Common Uses of NMs and UFPs (EPA 2007, 2008a; Klaine and others 2008; Watlington 2005; Gil and Parak 2008; Luoma 2008; Cota-Sanchez and Merlo-Sosa 2015) Types of NMs and UFPs Physical/Chemical Uses Examples (Occurrence) Properties Carbon-based Stable, limited reactivity, Biomedical applications, Fullerenes, multi-walled and (Natural or Engineered) excellent thermal and battery and fuel cell single-walled carbon electrical conductivity. electrodes, super- nanotubes (CNTs) and capacitors, adhesives and graphene materials. composites, sensors and components in electronics, aircraft, aerospace and automotive industries. Metal-based Materials High reactivity, varied Solar cells, paints and Nanogold, nanosilver, metal (Natural or Engineered) properties based on type, coatings, cosmetics, oxides such as titanium some have photolytic ultraviolet blockers in dioxide (TiO2), zinc oxide properties and ultraviolet sunscreen, environmental (ZnO), cerium dioxide blocking ability. Capping remediation. (CeO2) and nanoscale zero- agents are used in some valent iron (nZVI). cases. Quantum Dots Reactive core composed of Medical Bioimaging, Quantum dots made from (Engineered) metals or semiconductors targeted therapeutics, cadmium selenide (CdSe), controls the material’s solar cells, photonics and cadmium telluride (CdTe), optical properties. Cores are telecommunication. indium phosphide (InP) and surrounded by an organic zinc selenide (ZnSe). shell that protects from oxidation. Dendrimers Three-dimensional Drug delivery systems, Hyperbranched polymers, (Engineered) nanostructures engineered polymer materials, chemical dendrigraft polymers and to carry molecules sensors and modified dendrons. encapsulated in their interior electrodes. void spaces or attached to the surface. Composite NMs Composite NMs consist of Potential applications in drug Produced using two different (Engineered) multifunctional components delivery and cancer NMs or NMs combined with and have novel electrical, detection. Also used in auto larger, bulk-type materials. catalytic, magnetic, parts and packaging They can also be made with mechanical, thermal or materials to enhance NMs combined with imaging features. mechanical and flame- synthetic polymers or resins. retardant properties. 2 Technical Fact Sheet – Nanomaterials Existence of nanomaterials in the environment Engineered NMs may be released into the extrapolate to natural ecosystems (Haynes and environment primarily through industrial and others 2017). environmental applications, improper handling Toxic effects of nanosilver on fish have been or consumer waste (EPA 2007). observed and nanosilver may induce a stress NPs fate and transport in the environment are response in fish; however, the results of a 28- largely dependent on material properties such day study on rainbow trout indicated that as surface chemistry, particle size and although nanosilver did engage a stress biological and abiotic processes in response in fish, it did not affect growth or environmental media. Depending on these condition at environmentally relevant properties, NPs may stay in suspension as concentrations (0.28 micograms per liter) and individual particles, aggregate, dissolve or react higher concentrations (average 47.6 with other materials (EPA 2009; Luoma 2008). micrograms per liter) (Murray and others 2017). NZVI particles are one of the most widely used ZnO NPs affected the growth rate of the algae nanoparticles for environmental remediation and suggested that the ZnO NPs were more because of their ability to degrade a wide range toxic to the marine algae than bulk ZnO (Manzo of contaminants. Such an increasingly and others 2013). widespread application of nZVI will lead to its Recent studies have shown the following: release into the environment. The . Carbon fullerenes are insoluble and colloidal environmental fate and transport of nZVI is not aggregates in aqueous solutions are stable yet fully understood making it difficult to for months to years, allowing for chronic determine the environmental risk of nZVI exposure to biological and environmental injected into the subsurface (Jang and others systems (Hegde and others 2015). 2014). Single-walled CNTs are not readily degraded Many NMs containing inherently non- by fungal cultures or microbial communities biodegradable inorganic chemicals such as (Parks and others 2015). ceramics, metals and metal oxides are not . Coatings on iron oxide NPs caused different expected to biodegrade (EPA 2007). toxic effects, which were linked to Under conditions of low or no UV exposure, decreasing colloidal stability, the release of TiO2 NPs have been shown to cause mortality, ions from the core material or the ability to reduced growth and negative impacts on cells form reactive oxygen species in daphnids and DNA of aquatic organisms. Many of these (Baumann and others 2014). studies, however, neglect environmentally . The degradation of a surface coating of relevant interactions with acute exposure times TiO2 resulted in increased phototoxicity and high concentrations (greater than 10 nano- milligrams per liter) and thus are difficult to to a benthic organism (Wallis and others 2014). What are the routes of exposure to nanomaterials? The growing production and use of NMs in secondary organs such as the liver, heart, diverse industrial processes, construction, and spleen, or kidney, subsequent to pulmonary medical and consumer products is resulting in uptake (Laux and others 2017). increasing