Environmental Implications Of Nanotechnology Research Articles

Comparative study of silver nanoparticle permeation using Side-Bi-Side and Franz diffusion cells

Better understanding the mechanisms of nanoparticle permeation through membranes and packaging polymers has important implications for the evaluation of drug transdermal uptake, in food safety and the environmental implications of nanotechnology. In this study, permeation of 21 nm diameter silver nanoparticles (AgNPs) was tested using Side-Bi-Side and Franz static diffusion cells through hydrophilic 0.1 and 0.05 µm pore diameter 125 µm thick synthetic cellulose membranes, and 16 and 120 µm thick low-density polyethylene (LDPE) films. Experiments performed with LDPE films discarded permeation of AgNPs or Ag ions over the investigated time-frame in both diffusion systems. But controlled release of AgNPs has been quantified using semipermeable hydrophilic membranes. The permeation followed a quasi-linear time-dependent model during the experimental time-frame, which represents surface reaction-limited permeation. Diffusive flux, diffusion coefficients, and membrane permeability were determined as a function of pore size and diffusion model. Concentration gradient and pore size were key to understand mass transfer phenomena in the diffusion systems.

Crossing the Line – “Science” and “Decisions” Facing Emerging Technologies

The discussion in this special section has been stimulated by the National Research Council report: “Science and Decisions. Advancing Risk Assessment” [1]. In this title, two different domains are simultaneously linked and held apart by the word “and”. This word reveals the problem addressed in this special section. Science is comfortable in its own self-referential domain of theory-driven observation, methodical data generation, and hypothetical, i.e. provisional, knowledge production. Science’s world cannot be sustained without proper alimentation; hence, there is a lot of pressure to deliver “useful knowledge,” which is defined as the kind of knowledge that stimulates economic growth. Natural sciences and engineering sciences claim their advantage by providing results with practical functions, or at least results that may lead to functioning technological realities in the near future. Nowadays, even philosophical research is expected to prove its societal impact and usefulness by contributing to more customer-oriented, sustainable, and ethically defendable technological systems [2]. The crossing from “science” to “decisions” is unavoidable and mandatory, so it appears, but the interaction between science and decision-making is not straightforward. The regulator faces a “dilemma” [3]: On the one hand, decision-makers seem to be asking questions that science cannot give clear answers to (e.g., what are the environmental implications of nanotechnology?) under increasing public pressure. On the other hand, scientists provide answers, in ever greater detail, to questions that decision-makers did not ask or are not interested in (e.g., by what mechanisms do carbon nanotubes cause asbestos-like pathogenicity). Science does not deliver certainty, as the discussions about ignorance or non-knowledge illustrate: “Sometimes, to learn more is to discover hidden complexities that make us realize that the mastery we thought we had over phenomena was in part illusory” [4]. The realization of indeterminacies as a universal fact is like an unmovable object which collides with the irresistible force, i.e. the postulate to make decisions: “Only those questions that are in principle undecidable, we can decide” [5]. While we must decide on matters Nanoethics (2015) 9:255–260 DOI 10.1007/s11569-015-0244-z

Environmental Implications of Nanotechnology—An Update

Some engineers and scientists are either directly or indirectly involved with nanotechnology issues. Nanotechnology concerns dealing with environmental implications and regulatory compliance encompass practicing areas for these technical individuals. Areas of particular concern include current/proposed environmental regulations and procedures for quantifying both health risks and hazard risks. This article addresses both of these issues.

Nanotechnology: Environmental Implications and Solutions

By Louis Theodore and Robert G. Kunz Hoboken, NJ:John Wiley & Sons, 2005. 378 pp. ISBN: 0-471-69976-4, $99.95 cloth This book, written mainly for engineering students, gives an excellent summary of traditional environmental pollution issues. Ten chapters cover current legislation regarding environmental pollutants; an overview of chemistry and current nanotechnology processes; air, water and solid-waste issues; multimedia analysis; both health and hazard risk assessment; ethical considerations; and concluding remarks on future trends. Nanotechnology is emerging in a wide variety of applications, yet unfortunately very little is known about the environmental implications of engineered nanomaterials, of possible ways to handle engineered nano-materials as environmental pollutants, or of how nanomaterials behave in the environment when used for remediation. Therefore, such a book will increase awareness of potential problems, but may disappoint those who expect dramatic revelations about nanoparticles as pollutants. Due to the current paucity of data, the book gives a well-written overview of environmental toxicology of traditional toxicants, with only a bare mention of nanomaterials in introductions to each chapter. The exception is Chapter 2, which covers basic chemistry and various processes used in making nanosized materials. A few analytical tools currently used to study nanomaterials are discussed, followed by a good overview of the current and near-future uses of nanotechnology. Other chapters present traditional monitoring methods and pollution control methods in great detail, and are useful for teaching. However, the authors do not delve into the current literature showing that nanosized materials do not necessarily behave like bulk materials in water and soils and that it would be prudent to consider and develop new treatment or containments strategies. The long section on current pollution-related regulations implies that laws already exist that apply to engineered nanomaterials. However, the book does not mention several recent rulings stating that the nano-sized materials are not considered different from bulk (until or unless they receive their own Chemical Abstracts Service numbers), and therefore most of the legislation does not apply to these materials. Although Occupational Safety and Health Administration legislation is mentioned, the impressive ongoing effort by scientists from the National Institute for Occupational Safety and Health to develop monitoring tools and toxicity data for nanosized materials is absent from this section. Because much of the information currently known about nano-sized particles comes from air pollution and inhalation toxicology, the section on air pollution is more robust than other chapters in terms of nano-implications. But the section contains some inaccuracies. The authors assume that nanosized materials behave as gases—which is true only for very small particles (~ < 5 nm). When particle concentrations increase, they can quickly aggregate and behave like larger-sized particles. There is bare mention of the importance of particle chemistry, surface chemistry, concentration, shape, and size in nanoparticles or engineered nanomaterial behavior as air pollutants. Other inaccuracies include the statement that there is no information on deposition of nanosized particles in the respiratory tract, and repeated misuse of terms such as “particulate” versus “particle.” However, these inaccuracies do not distract from the otherwise thorough discussions of pollution issues that introduce the interested engineer to ecotoxicology. The water and solid-waste sections of the book focus on traditional toxicants as case studies and give a detailed description of current waste-water and solid-waste treatment. With few toxicity or exposure data available, the risk assessment and hazard assessment sections focus on traditional toxicants as case studies—a good foundation for future engineers dealing with the emerging risks and hazards of nanotechnology. A chapter on ethics presents several fictional scenarios, useful in classroom discussions on environmental ethics and the role of environmental engineers in monitoring and responsible whistle blowing. Overall, the book’s good overview of traditional (bulk) toxicants serves as background for potential nanosized material problems. Given the scarcity of data about nanoecotoxicology, very little information now exists on environmental implications of nanotechnology. Such information should become available over the next 5 years, contributing to a second edition of this book.