2.2 Environmental risk management  (Page 4/3)

Learning objectives

After reading this module, students should be able to

• trace the basic elements of the sustainability paradigm through the evolution of U.S. environmental policy, including the National Environmental Policy Act of 1970
• understand the role of risk management as modern environmental policy has been implemented

General definitions

For most people, the concept of risk is intuitive and, often, experiential; for instance most people are aware of the considerably greater likelihood of suffering an injury in an automobile accident (116/100 million vehicle miles) versus suffering an injury in a commercial airplane accident (0.304/100 million airplane miles). Environmental risk can be defined as the chance of harmful effects to human health or to ecological systems resulting from exposure to any physical, chemical, or biological entity in the environment that can induce an adverse response (see Module Risk Assessment Methodology for Conventional and Alternative Sustainability Options for more detail on the science of risk assessment). Environmental risk assessment is a quantitative way of arriving at a statistical probability of an adverse action occurring. It has four main steps:

1. Identification of the nature and end point of the risk (e.g. death or disability from hazardous chemicals, loss of ecological diversity from habitat encroachment, impairment of ecosystem services, etc.)
2. Development of quantitative methods of analysis (perturbation-effect, dose-response)
3. Determination of the extent of exposure (i.e. fate, transport, and transformation of contaminants to an exposed population), and
4. Calculation of the risk, usually expressed as a statistical likelihood.

Risk management is distinct from risk assessment, and involves the integration of risk assessment with other considerations, such as economic, social, or legal concerns, to reach decisions regarding the need for and practicability of implementing various risk reduction activities. Finally, risk communication consists of the formal and informal processes of communication among various parties who are potentially at risk from or are otherwise interested in the threatening agent/action. It matters a great deal how a given risk is communicated and perceived: do we have a measure of control, or are we subject to powerful unengaged or arbitrary forces?

The beginnings of modern risk management

The beginnings of environmental risk management can be traced to the fields of public health , industrial hygiene , and sanitary engineering , which came into prominence in the latter decades of the 19 ^th century and beginning of the 20 ^th . The spread of disease was a particularly troublesome problem as the country continued to urbanize. For instance if you lived your life in, say, Chicago during the period 1850-1900 (a typical lifespan of the day), you had about a 1 in 100 chance of dying of cholera (and a 1 in 2000 chance of dying of typhoid), of which there were periodic epidemics spread by contaminated drinking water. Chicago's solution was to cease polluting its drinking water source (Lake Michigan) by reversing the flow of its watercourses so that they drained into the adjacent basin (the Mississippi). The widespread chlorination of municipal water after 1908 essentially eliminated waterborne outbreaks of disease in all major cities (with some notable exceptions—the outbreak of chlorine-resistant Cryptosporidium parvum in Milwaukee's drinking water in 1993 resulted in the infection of 403,000 people with 104 deaths).