Exposure Assessment: Recommendations for Nanotechnology-Based Pesticides

Abstract

Given the development of nanotechnology within numerous scientific disciplines, it is likely that nanoscale products have been and will be used for agricultural, vector, and urban pest control prior to a complete evaluation of exposure and risk. Significant differences may exist between nanotechnology-based pesticides (NBPs) and conventional pesticides, primarily due to size and surface characteristics. These differences may result in changes in bioavailability, sensitivity, dosimetry, and pharmacokinetics. This paper considers the role of exposure assessment in the regulation of NBPs. While the existing regulatory infrastructure for pesticides is well established, several issues specific to NBP exposure are discussed, including: (1) disclosures of nanoparticle characteristics in product formulations; (2) additional uncertainty factors for NBPs with inadequate data; (3) route-specific approaches for assessing exposure; (4) testing with the commercial form of NBPs; (5) initiation of a health surveillance program; and (6) development of educational programs.     

United States Government Accountability Office Report on Nanotechnology: Nanomaterials Are Widely Used in Commerce,but EPA Faces Challenges in Regulating Risk

Abstract

Nanotechnology involves the ability to control matter at the scale of a nanometer—one billionth of a meter. The world market for products that contain nanomaterials is expected to reach $2.6 trillion by 2015. In this context, the United States Government Accountability Office (GAO): (1) identified examples of current and potential uses of nanomaterials, (2) determined what is known about the potential human health and environmental risks from nanomaterials, (3) assessed actions the Environmental Protection Agency (EPA) has taken to better understand and regulate the risks posed by nanomaterials as well as its authorities to do so, and (4) identified approaches that other selected national authorities and US states have taken to address the potential risks associated with nanomaterials. The GAO analyzed selected laws and regulations, reviewed information on the EPA's Nanoscale Materials Stewardship Program, and consulted with EPA officials and legal experts to obtain their perspectives on the EPA's authorities to regulate nanomaterials.     

Effectiveness of a Custom-fitted Flange and Local Exhaust Ventilation (LEV) System in Controlling the Release of Nanoscale Metal Oxide Particulates During Reactor Cleanout Operations

Abstract

As the nanotechnology industry expands, facilities engaged in the production and use of engineered nanoscale materials (ENMs) are challenged with determining whether their processes pose a risk for worker inhalation exposure. Although there are neither regulatory exposure limits specific to ENMs nor validated measurement standards for nanomaterials in the workplace, many facilities opt to be proactive in managing uncharacterized ENMs by reducing or eliminating the potential for exposure by controlling their release into the workplace atmosphere. A field study was conducted to evaluate the effectiveness of a portable, HEPA-filtered, local exhaust ventilation system equipped with a custom-fitted flange for controlling the emission of engineered nanoscale metal oxide particulates during reactor cleanout operations. On the basis of the findings of this study, it appears that a properly designed LEV system, coupled with good work practices can be highly effective in controlling nanoscale material emissions during processes of this type.     

Characterization of Exposures To Nanoscale Particles and Fibers During Solid Core Drilling of Hybrid Carbon Nanotube Advanced Composites

Abstract

This work investigated exposures to nanoparticles and nanofibers during solid core drilling of two types of advanced carbon nanotube (CNT)-hybrid composites: (1) reinforced plastic hybrid laminates (alumina fibers and CNT); and (2) graphite-epoxy composites (carbon fibers and CNT). Multiple real-time instruments were used to characterize the size distribution (5.6 nm to 20 μm), number and mass concentration, particle-bound polyaromatic hydrocarbons (b-PAHs), and surface area of airborne particles at the source and breathing zone. Time-integrated samples included grids for electron microscopy characterization of particle morphology and size resolved (2 nm to 20 μm) samples for the quantification of metals. Several new important findings herein include generation of airborne clusters of CNTs not seen during saw-cutting of similar composites, fewer nanofibers and respirable fibers released, similarly high exposures to nanoparticles with less dependence on the composite thickness, and ultrafine (< 5 nm) aerosol originating from thermal degradation of the composite material.     

Insight into the Behavior of Engineered Aerosolized Nanoparticles: A Method for Understanding their Fate from an Aerosol Release in the Workplace Environment

Abstract

We present a method to assess the behavior of aerosol nanoparticles as a function of time and of selected aerosol chamber and environmental conditions upon exposure to polydisperse silicon dioxide (SiO₂) aerosol nanoparticles (NPs). Through synthesis of SiO₂ aerosol NPs, a well-controlled, stable source of aerosol NPs was used to probe aerosol behavior in an enclosed aerosol chamber. This paper describes a procedure to interface an aerosol chamber downstream of a SiO₂ aerosol NP reactor that is capable of synthesizing SiO₂ NPs with particle diameters from 10 to 100 nm at particle concentrations of ～10⁴ to 10⁷ particles/cm³. This paper also describes the relative impact on aerosol and aerosol chamber variables, such as chamber volume, the entering aerosol NP size distribution, and environmental parameters, such as relative humidity and ambient particle concentrations, on the observed changes in aerosol NPs over time under unmixed conditions. These findings provide insights into aerosol NP behavior under ideal, well-controlled conditions which can be further refined to include more occupationally relevant conditions that would be important for establishing guidance on suitable workplace containment and controls.     

Trends of nanotechnology in type 2 diabetes mellitus treatment

There are several therapeutic approaches in type 2 diabetes mellitus(T2DM).When diet and exercise fail to control hyperglycemia,patients are forced to start the...     

Current update on nanoplatforms as therapeutic and diagnostic tools:A review for the materials used as nanotheranostics and imaging modalities

In the last decade,the use of nanotheranostics as emerging diagnostic and therapeutic tools for various diseases,especially cancer,is held great attention.Up to date,several approaches have been employed in order to develop smart nanotheranostics,which combine bioactive targeting on specific tissues as well as diagnostic properties.The nanotheranostics can deliver therapeutic agents by concomitantly monitor the therapy response in real-time.Consequently,the possibility of over-or under-dosing is decreased.Various non-invasive imaging techniques have been used to quantitatively monitor the drug delivery processes.Radiolabeling of nanomaterials is widely used as powerful diagnostic approach on nuclear medicine imaging.In fact,various radiolabeled nanomaterials have been designed and developed for imaging tumors and other lesions due to their efficient characteristics.Inorganic nanoparticles as gold,silver,silica based nanomaterials or organic nanoparticles as polymers,carbon based nanomaterials,liposomes have been reported asmultifunctional nanotheranostics.In this review,the imaging modalities according to their use in various diseases are summarized,providing special details for radiolabeling.In further,the most current nanotheranostics categorized via the used nanomaterials are also summed up.To conclude,this review can be beneficial for medical and pharmaceutical society as well as material scientists who work in the field of nanotheranostics since they can use this research as guide for producing newer and more efficient nanotheranostics.