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Nanotechnology and the Environment - Chapter 9

Đánh giá nguy cơ độc tính, một công cụ phổ biến trong khoa học quản lý, các dự án hoặc đặc điểm tiềm năng và mức độ cho một tình huống nhất định để dẫn đến một tác dụng phụ được xác định có hiệu lực. Nó thường liên quan đến việc xem xét một tỷ lệ tiếp xúc, sau đó so sánh tỷ lệ có liên quan đến một phản ứng độc hại cho. | 9 Toxicology and Risk Assessment Chris E. Mackay and Jane Hamblen AMEC Earth Environmental CONTENTS 9.1 Risk Assessment and Nanomaterials.194 9.1.1 Effects of Steric Hindrance.194 9.1.2 Inflammatory and Immune-Based Mechanisms.195 9.1.3 Critical Variables.195 9.2 Exposure and Effects through Ingestion.196 9.2.1 Diffusion.196 9.2.2 Endocytosis . 199 9.3 Exposure and Effects through Dermal Absorption.200 9.4 Exposure and Effects through Inhalation.201 9.4.1 Mechanisms for Adsorption and Removal . 201 9.4.2 Case Study Inhalation of Carbon Nanotubes.205 9.4.2.1 Pulmonary Toxicology.205 9.4.2.2 Risk Assessment.207 9.6 Known Toxicity of Nanomaterials.209 9.7 Conclusions . 220 9.8 List of Symbols.220 References . 221 Toxicological risk assessment a common tool in regulatory science projects or characterizes the potential and extent for a given situation to result in a defined adverse effect. It usually involves a consideration of an exposure rate which is then compared to a rate related to a given toxic response. Risk then is quantified based on the possibility or probability of the exposure rate meeting or exceeding the rate that causes toxicity. Both exposure and response depend on an agent s chemistry relative to its environmental transport distribution and fate within the target organism pharmacokinetics and its ability to elicit an adverse response at one or more sites or receptors activity . Any change in the chemical disposition of an agent that affects exposure pharmacokinetics or activity inevitably will alter the projections of potential adverse effect and thereby the risk. 193 2009 by Taylor Francis Group LLC 194 Nanotechnology and the Environment A nanomaterial is a particulate manifestation of one or more identifiable chemicals combined as an insoluble entity in its medium of transport. Because covalent interactions would negate the particle s identity as a nanomaterial interactions with the suspending medium usually involve only weak or Coulomb forces. By .