Environmental Toxicity of Nanomaterials

Vineet Kumar, Nandita Dasgupta, Shivendu Ranjan, Vineet Kumar, Nandita Dasgupta, Shivendu Ranjan

• Publisher: CRC Press
• Year: 2018
• ISBN:
  9781351252942
• Edition: 1
• Topic: Medicina
• Subtopic: Tossicologia

Environmental Toxicity of Nanomaterials focuses on causes and prevention of environmental toxicity induced by various nanomaterials. In sixteen chapters it describes the basic principles, trends, challenges, and future directions of nanoecotoxicity.

The future acceptance of nanomaterials in various industries depends on the impacts of nanomaterials on the environment and ecosystem. This book analyzes the safe utilization of nanotechnology so the tremendous prospect of nanotechnology can be achieved without harming either living beings or the environment.

Environmental Toxicity of Nanomaterials introduces nanoecotoxicity, describes various factors affecting the toxicity of nanomaterials, discusses various factors that can impart nanoecotoxicity, reviews various studies in the area of nanoecotoxicity evaluation, and describes the safety and risk assessment of nanomaterials. In addition, the book discusses strategies for mitigating nanoecotoxicity. Lastly, the authors provide guidelines and protocols for nanotoxicity evaluation and discuss regulations for safety assessment of nanomaterials. In addition to environmental toxicologists, this book is aimed at policy makers, industry personnel, and doctoral and postdoctoral scholars.

1Toxic Effects of Nanomaterials on Environment

Rajeev Kumar, Moondeep Chauhan, Neha Sharma, and Ganga Ram Chaudhary

1.1Introduction

1.2Risk and Hazard of Exposure to Nanomaterials

1.3Fate and Behavior of Nanomaterials in the Environment

1.3.1Fate and Behavior of Nanomaterials in Air

1.3.2Fate and Behavior of Nanomaterials in Water

1.3.3Environmental Fate of Nanomaterials in Soil

1.4Human Exposure

1.4.1Exposure through Inhalation

1.4.2Exposure through Dermal Deposition

1.4.3Exposure through Ingestion

1.5Bioaccumulation of Nanomaterials

1.6Effect of Nanomaterials on Agriculture and Food

1.7Conclusion

References

1.1Introduction

According to the definition given by the US National Nanotechnology Initiative, nanotechnology may be defined as understanding and control of matter at dimensions of roughly 1–100 nm, where unique phenomena enable novel applications. At this level, the physical, chemical, and biological properties of materials differ in fundamental and valuable ways from the properties of individual atoms and molecules or bulk matter. This means that at least one dimension in the approximate range of 1–100 nm and difference in the properties of matter from that of its bulk form are the two fundamental criteria which must be satisfied in order to consider a material as nanomaterial. This definition is extensively broad under which different materials are covered, and undoubtedly nanotechnology has origins, significance, and application in different fields such as agriculture, aerogels, aerospace, automotive, catalysts, coatings, paints and pigments, composites, construction, cosmetics, electronics, optics, energy, environmental remediation, filtration and purification, food products, medical, packaging, paper and board, plastics, security, sensors, and textiles, and research is underway on many new applications. Hence, nanotechnology is generally defined as a cross disciplinary technology (Foss Hansen et al. 2007).

Similar to conventional substances, it is now known that some nanomaterials may be hazardous, and thus demand for standardization of the term nanomaterial and various other terms related to nanotechnology has increased. Many countries and standardization organizations have developed working definitions to identify nanomaterials based on the size of the material, its novel properties, or a combination of both, depending on their scope and the type of applications. For example, according to the International Organization for Standardization (ISO 2010), nanomaterial may be defined as “material with any external dimension in the nanoscale or having internal structure or surface structure in the nanoscale,” where nanoscale is “length ranging from approximately 1 nm to 100 nm” (Saner and Stoklosa 2013). The European Union defines nanomaterial as a “natural, incidental or manufactured material containing particles, in an unbound state or as aggregate or as an agglomerate and where, for 50% or more of the particles in the number size distribution, one or more external dimensions is in the size range 1nm–100 nm. In specific cases where concerns exist for environment, health, safety or competitiveness they provide exception that number size distribution threshold of 50% may be replaced by a threshold between 1% and 50%.” The emphasis in the definition on external dimensions may exclude materials with an internal structure (e.g., porous materials with relatively large internal surface area) or materials with a surface structure at the nanoscale. Thus, it is becoming clear that many parameters other than size modulate risk, including particle shape, porosity, surface area, and chemistry. Some of these parameters become more relevant at smaller scales—but not always. The transition from “conventional” to “unconventional” behavior, when it does occur, depends critically on the particular material and the context. A “one size fits all” definition of nanomaterials will fail to capture what is important for addressing risk (Maynard 2011).

Nanomaterials can be classified into different types on the basis of their source, dimensions, and chemical composition and their potential toxicity level (Dolez 2015). Erupting volcanoes, breaking sea waves, forest fires, sand storms, and soils are some of the major natural sources of inorganic nanomaterials. Some nanomaterials such as ferritin, calcium hydroxyapatite, biogenic magnetite, and ferromagnetic crystalline are naturally found in living organisms and thus are an organic source of nanomaterials. Some nanomaterials are unintentionally produced as by-products of human activity such as internal combustion engines, power plants, incinerators, jet engines, metal fumes (smelting, welding, etc.), polymer fumes, heated surfaces, food transformation processes (baking, frying, broiling, grilling, etc.), and electric motors. Finally, nanomaterials are now manufactured using a large diversity of chemical constituents, for example, metals, semiconductors, metal oxides, carbon, and polymers. There are some nanomaterials designed for specific functionalities and can be surface treated or coated. They come in a large variety of forms, such as spheres, wires, fibers, needles, rods, shells, rings, plates, and coatings, as well as in more exotic flower-like designs. Compared to natural and incidental nanomaterials, manufactured nanomaterials are characterized by their controlled dimension, shape, and composition.

On the basis of dimensionality, nanomaterials can be categorized as zero-dimensional (0D), one-dimensional (1D), two-dimensional (2D), and three-dimensional nanomaterials (3D). Zero-dimensional nanomaterials have all the three external dimensions at the nanoscale (i.e., between 1 and 100 nm), for example quantum dots and metal oxide nanoparticles (NPs). 1D nanomaterials have two external dimensions at the nanoscale, the third one being usually at the microscale such as nanofibers, nanotubes, nanowires, and nanorods. With only one external dimension at the nanoscale, 2D nanomaterials comprise thin films, nanocoatings, and nanoplates....