Đánh giá rủi ro đã trở nên ngày càng quan trọng đối với y tế công cộng trong những năm gần đây. Thật vậy, yêu cầu đánh giá chính thức của nguy cơ để cung cấp nước từ cryptosporidiosis gần đây đã được ghi nhận trong Luật của Anh. 1 Khi người ta xem xét nguy cơ đối với sức khỏe cộng đồng từ sự hình thành màng sinh học, có rất ít nguồn trực tiếp bằng chứng. Do đó, người ta phải sử dụng một hoặc nhiều hơn của các mô hình khác nhau của rủi ro đánh giá. Viện Hàn lâm Khoa học Quốc gia. | 4 Risk Assessment CONTENTS Definition of Role of Risk Assessment Epidemiological Risk Standard Risk INTRODUCTION Risk assessment has become increasingly important to public health in recent years. Indeed the requirement to do formal assessments of the risk to water supply from cryptosporidiosis has recently been enshrined in British When one considers the risk to public health from biofilm formation there are very few sources of direct evidence. Consequently one has to use one or more of the various models of risk assessment. The National Academy of Sciences defined risk assessment as the use of the factual base to define the health effects of exposure of individuals or populations to hazardous materials and This definition does not however give much insight into the nature of risk and the processes involved in risk assessment. A further problem is that much of the information to do adequate risk assessments does not exist. This chapter discusses risk assessment by first defining risk and looking at the role of risk assessment and then by describing some approaches to risk assessment that are applicable to the water industry. DEFINITION OF RISK Risk means very different things to different people. In the chapter on epidemiology we have already come across several definitions of risk. More generally risk was defined as the number of new cases of disease in a population of a known size over a given period of time . the incidence of disease . We also defined relative risk the ratio of incidence in an exposed and nonexposed population and attributable risk the incidence owing to exposure to a specific factor . More generally risk can be defined as the possibility of loss harm or injury. This definition contains within it two concepts harm and probability. This brings us to our first risk assessment model. Risk can be
