questions below
20160709230556chapter_1.pdf
20160709230604chapter_2.pdf
20160709230722chapter_3.pdf
20160709230617chapter_4.pdf
Unformatted Attachment Preview
PRINTED BY: Stephanie Schicchi . Printing is for personal, private use only. No part of this book may be reproduced or transmitted without
publisher’s prior permission. Violators will be prosecuted.
3
CHAPTER 1 Introduction: The Environment at Risk
LEARNING OBJECTIVES
By the end of this chapter the reader will be able to:
•
Describe how environmental health problems influence our lives
•
Describe the potential impacts of population growth upon the environment
•
State a definition of the term environmental health
•
List at least five major events in the history of environmental health
•
Identify current issues in the environmental health field
•
Describe employment opportunities in the environmental health field
INTRODUCTION
This chapter will illustrate how environmental health relates to our lives and delimit the scope of the
environmental health field. The author will define key terms used in environmental health, present some of
the distinguishing features of the field, and introduce several of the basic concepts, which are essential to
students of this discipline. For example, one of these concepts is the relationship between world population
growth and the environment. Another concept relates to historically significant environmental events and
how they influenced the topics that are of current importance to the environmental health field. An additional
topic involves employment classifications, career roles, and opportunities for environmental health workers.
The chapter will conclude with an overview of the textbook: the roles of environmental epidemiology and
toxicology, policy aspects of environmental health, examples of environmentally related agents and diseases,
and specific content areas of environmental health such as air quality, water quality, food safety, and waste
disposal.
Maintaining environmental quality is a pressing task for the 21st century. Improvement in environmental
quality is an official goal of the US government, as articulated in Healthy People 2010. This goal (number 8,
1(p55)
Environmental Health) is formatted as follows: “Promote health for all through a healthy environment.”
A list of environmental objectives is shown in Table 1-1. Note that Healthy People 2020, which will provide
updated objectives, was not available as of this writing.
According to Healthy People 2010:
Physical and social environments play major roles in the health of individuals and communities. The
physical environment includes the air, water, and soil through which exposure to chemical, biological,
and physical agents may occur. The social environment includes housing, transportation, urban
development, land use, industry, and agriculture and results in exposures such as work-related stress,
1(p41)
injury, and violence.
Essentials of Environmental Health, 2nd Edition
Page 1 of 39
PRINTED BY: Stephanie Schicchi . Printing is for personal, private use only. No part of this book may be reproduced or transmitted without
publisher’s prior permission. Violators will be prosecuted.
Protecting the environment means creating a world in which the air is safe to breathe, the water is safe to
drink, the land is arable and free from toxins, wastes are managed effectively, infectious diseases are kept at
bay, and natural areas are preserved. Figure 1-1 illustrates a beautifully maintained natural area in the United
States.
The requirements of a growing world population need to be balanced against the demands for environmental
preservation. Although developed countries such as the United States have made substantial progress in
clearing the air and reducing air pollution, significant challenges to the environment and human health
remain. For example, among the current and continuing threats to the environment in the United States are
the following: trash that fouls our beaches, hazardous wastes (including radioactive wastes) leaching from
disposal sites, continuing episodes of air pollution in some areas, exposures to toxic chemicals, and
destruction of the land through deforestation.
Essentials of Environmental Health, 2nd Edition
3
4
Page 2 of 39
PRINTED BY: Stephanie Schicchi . Printing is for personal, private use only. No part of this book may be reproduced or transmitted without
publisher’s prior permission. Violators will be prosecuted.
TABLE 1-1 Objectives for Healthy People 2010—Goal Number 8, Environmental
Health: Promote Health for All through a Healthy Environment
Outdoor Air Quality
8-1 Harmful air pollutants
8-2 Alternative modes of transportation
8-3 Cleaner alternative fuels
8-4 Airborne toxins
Water Quality
8-5 Safe drinking water
8-6 Waterborne disease outbreaks
8-7 Water conservation
8-8 Surface water health risks
8-9 Beach closings
8-10 Fish contamination
Toxics and Waste
8-11 Elevated blood lead levels in children
8-12 Risks posed by hazardous sites
8-13 Pesticide exposures
8-14 Toxic pollutants
8-15 Recycled municipal solid waste
Healthy Homes and Healthy Communities
8-16 Indoor allergens
8-17 Office building air quality
8-18 Homes tested for radon
8-19 Radon-resistant new home construction
8-20 School policies to protect against environmental hazards
8-21 Disaster preparedness plans and protocols
8-22 Lead-based paint testing
8-23 Substandard housing
Essentials of Environmental Health, 2nd Edition
Page 3 of 39
PRINTED BY: Stephanie Schicchi . Printing is for personal, private use only. No part of this book may be reproduced or transmitted without
publisher’s prior permission. Violators will be prosecuted.
Infrastructure and Surveillance
8-24 Exposure to pesticides
8-25 Exposure to heavy metals and other toxic chemicals
8-26 Information systems used for environmental health
8-27 Monitoring environmentally related diseases
8-28 Local agencies using surveillance data for vector control
Global Environmental Health
8-29 Global burden of disease
8-30 Water quality in the US-Mexico border region
Source: Data from US Department of Health and Human Services. Healthy People 2010: Understanding and Improving
Health. 2nd ed. Washington, DC: US Government Printing Office; November 2000:55.
The hallmarks of environmental degradation are not difficult to find: Warning signs posted on beaches advise
bathers not to enter ocean water that is unsafe because of sewage contamination. In some areas of the United
States, drinking water is threatened by toxic chemicals that are leaching from disposal sites. Factories in some
areas continue to belch thick, black smoke. Avoidance of air pollution, which at best insults our aesthetic
senses and at worst endangers our health, is often impossible. Society’s appetite for lumber and new housing
to satisfy the burgeoning population has resulted in clear-cutting of forests and destruction of wildlife habitats
in order to accommodate new habitations for humans.
Pollution and population growth, often associated with adverse economic circumstances, are closely
connected with environmental health. In his classic article, Professor Warren Winkelstein wrote that “the
2(p932)
three P’s—pollution, population, and poverty—are principal determinants of health worldwide. . . .”
The three P’s are interrelated: Population growth is associated with poverty, and both poverty and population
growth are associated with pollution.
An example of the first “P” is pollution from combustion of fossil fuels (e.g., petroleum and coal), which
disperses greenhouse gases along with other pollutants into the atmosphere. This process is believed to be a
cause of global warming that in turn may have wide-ranging effects. One such effect is to advance the range
of disease-carrying insects, bringing them into new geographic areas; for example, mosquito-borne diseases
such as the West Nile virus and dengue fever may appear in areas that previously were free from these
conditions. (Refer to Chapter 5 for more information.) The second “P” is population, which is growing
exponentially in many parts of the world, especially the less developed areas, and may result in a worldwide
population of up to 10 to 12 billion people during the 21st century; the presence of so many people may
exceed the carrying capacity (defined later in the chapter) of the earth by a factor of two. The third “P,”
poverty, is linked to population growth; poverty is one of the well-recognized determinants of adverse health
outcomes.
A recent environmentally related adverse health outcome may be attributed, at least in part, to one of the three
P’s: population growth (which is associated with urban crowding). As a result of known and unknown
environmental and other factors, threats to the human population periodically arise from infectious disease
Essentials of Environmental Health, 2nd Edition
Page 4 of 39
PRINTED BY: Stephanie Schicchi . Printing is for personal, private use only. No part of this book may be reproduced or transmitted without
publisher’s prior permission. Violators will be prosecuted.
agents. (This topic is discussed in Chapter 5.) For example, influenza viruses threaten the world’s population
from time to time. Environmental factors that are likely to advance the spread of influenza viruses include
intensive animal husbandry practices needed to supply food to the world’s growing population. These
practices create extremely crowded conditions among food animals coupled with their close residential
proximity to humans. Several years ago, public health officials became concerned about the possible
occurrence of a human pandemic of avian influenza, caused by the avian influenza A (H5N1) virus. Large
outbreaks of avian influenza occurred on poultry farms in Asia. Apparently, some transmission of the virus
from birds to humans also occurred. The disease (called bird flu) produces a severe human illness that has a
high fatality rate. Health officials were concerned that the virus might mutate, enabling human-to-human
transmission; if human-to-human transmission of the virus erupted, a pandemic might result. In addition,
contributing to the possible epidemic transmission of influenza (and other communicable diseases) is the
ability of human beings to travel rapidly from one area of the globe to another. Exhibit 1-1 presents a case
study of pandemic influenza (H1N1). In 2009, swine flu (H1N1 influenza) spread through North America to
other parts of the globe. The World Health Organization (WHO) declared a pandemic.
4
5
FIGURE 1-1 A natural ecosystem in the United States. Maintaining
environmental quality is a pressing task for the 21st century.
Essentials of Environmental Health, 2nd Edition
Page 5 of 39
PRINTED BY: Stephanie Schicchi . Printing is for personal, private use only. No part of this book may be reproduced or transmitted without
publisher’s prior permission. Violators will be prosecuted.
SIGNIFICANCE OF THE ENVIRONMENT FOR HUMAN HEALTH
The environment is intimately connected with human health, illness, and mortality: Some estimates place the
3
toll of the world’s deaths caused by environmental factors at 40%. Exposures to potentially hazardous agents
such as microbes, toxic chemicals and metals, pesticides, and ionizing radiation account for many of the
forms of environmentally associated morbidity (acute and chronic conditions, allergic responses, and
disability) and mortality that occur in today’s world. These environmentally related determinants are believed
to be important for the development of chronic diseases such as cancer, although most chronic diseases are
4
thought to be the result of complex interactions between environmental and genetic factors. All human
beings are affected in some way by exposure to environmental hazards associated with lifestyle: at work, at
home, during recreation, or while traveling on the expressway. Table 1-2 provides examples of the scope of
disease burden associated with exposure to environmental hazards.
TABLE 1-2 The Scope of Environmental Health Problems in the World and the
United States
Some estimates report that 25% to 33% of the global burden of disease is linked to environmental sources.
During the late 1900s, approximately 1.2 billion pounds of potentially neurotoxic chemicals were released into the air
and waterways in the United States.
Elevated blood levels of lead continue to be an important problem in the United States with nearly 1 million children
exceeding the threshold for acceptable blood lead levels.
The prevalence and mortality of asthma in the United States have increased since 1980 by 58% and 78%, respectively.
Exposure to toxic chemicals is thought to cause as many as 3% of developmental and neurological problems in children
in the United States.
Using air quality standards established by the World Health Organization (WHO), experts have estimated that 1.3 billion
of the world’s urban inhabitants breathe air that exceeds these quality standards.
Environmental factors are thought to contribute significantly to many forms of cancer, including cervical cancer,
prostate cancer, and breast cancer.
Definition of terms used in the table:
Burden of disease is defined as “The total significance of disease for society beyond the immediate cost of treatment. It is
measured in years of life lost to ill health as the difference between total life expectancy and disability-adjusted life
expectancy.”
5
Life expectancy refers to the expectation of the number of years of life at birth; disability-adjusted life expectancy refers to
the number of years of healthy life expected in a particular population.
5
Source: Data from PG Butterfield. Upstream reflections on environmental health: An abbreviated history and framework for
action. Advances in Nursing Science. 2002;25:34.
Essentials of Environmental Health, 2nd Edition
5
Page 6 of 39
PRINTED BY: Stephanie Schicchi . Printing is for personal, private use only. No part of this book may be reproduced or transmitted without
publisher’s prior permission. Violators will be prosecuted.
5
6
Vulnerable Subgroups of the Population
The elderly, persons with disabilities and chronic diseases, pregnant women, and children are more likely to
be affected by environmental hazards than are members of the general population. For example, children
represent an especially vulnerable group with respect to exposure to hazardous materials, including
pesticides and toxic chemicals. Their immune systems and detoxifying organs are still developing and are
6
not fully capable of responding to environmental toxins. Children may be exposed more often than adults
78
to toxic chemicals in the ambient outdoor air and in the soil because they spend more time outside. ,
Environmental Health and the Developing World
Exhibit 1-1 CASE STUDY: Pandemic Influenza (H1N1) 2009
On April 17, 2009, the CDC determined that two cases of febrile respiratory illness occurring in
children who resided in adjacent counties in southern California were caused by infection with a swine
influenza A (H1N1) virus. . . . Neither child had contact with pigs; the source of the infection is
unknown. . . . Although this is not a new subtype of influenza A in humans, concern exists that this
new strain of swine influenza A (H1N1) is substantially different from human influenza A (H1N1)
viruses, that a large proportion of the population might be susceptible to infection, and that the seasonal
influenza vaccine H1N1 strain might not provide protection. The lack of known exposure to pigs in the
two cases increases the possibility that human-to-human transmission of this new influenza virus has
occurred.
Since April 21, 2009, the CDC has reported cases of respiratory infection with a swine-origin influenza
A (H1N1) virus (S-OIV) transmitted through human-to-human contact. . . . As of April 28, the total
number of confirmed cases of S-OIV infection in the United States had increased to 64, with cases in
California (10 cases), Kansas (two), New York (45), Ohio (one), and Texas (six).
Since mid-April 2009, the CDC, state and local health authorities in the United States, the World
Health Organization (WHO), and health ministries in several countries have been responding to an
outbreak of influenza caused by a novel influenza A (H1N1) virus. In March and early April 2009,
Mexico experienced outbreaks of respiratory illness subsequently confirmed by the CDC and Canada
to be caused by the novel virus. The influenza strain identified in US patients was genetically similar to
viruses isolated from patients in Mexico. . . . On April 29, the WHO raised the level of pandemic alert
from phase 4 to phase 5, indicating that human-to-human spread of the virus had occurred in at least
two countries in one WHO region. The government of Mexico has instituted several measures to slow
disease transmission and reduce mortality, including closure of all schools and avoidance of large
public gatherings.
The emergence and spread of the 2009 pandemic influenza A (H1N1) virus (2009 H1N1) resulted in
extraordinary influenza activity in the United States throughout the summer and fall months of 2009. . .
. During this period, influenza activity reached its highest level in the week ending October 24, 2009,
with 49 of 50 states reporting geographically widespread disease. As of January 9, 2010, overall
Essentials of Environmental Health, 2nd Edition
Page 7 of 39
PRINTED BY: Stephanie Schicchi . Printing is for personal, private use only. No part of this book may be reproduced or transmitted without
publisher’s prior permission. Violators will be prosecuted.
influenza activity had declined substantially. Since April 2009, the dominant circulating influenza virus
in the United States has been 2009 H1N1.
February 5, 2010—As of January 31, 2010, worldwide more than 209 countries and overseas territories
or communities have reported laboratory confirmed cases of pandemic influenza H1N1 2009, including
at least 15,174 deaths.
Source: Adapted and reprinted from the Centers for Disease Control and Prevention. Swine influenza A (H1N1)
infection in two children—Southern California, March-April 2009. MMWR. 2009;58:400; the Centers for
Disease Control and Prevention. Update: Infections with a swine-origin influenza A (H1N1) virus—United
States and other countries, April 28, 2009. MMWR. 2009;58:431; the Centers for Disease Control and
Prevention. Update: Novel influenza A (H1N1) virus infections—worldwide, May 6, 2009. MMWR. 58:453; the
Centers for Disease Control and Prevention. Update: Influenza activity—United States, August 30,2009-January
9, 2010. MMWR. 2010;59:38; and the World Health Organization. Pandemic (H1N1) 2009—update 86. Weekly
update. Available at: http://www.who.int/csr/don/2010_02_5/en. Accessed February 7, 2010.
Residents of developing countries suffer far more from problems associated with environmental
degradation than do those who live in developed countries; this observation holds true despite the fact that
developed countries are highly industrialized and disseminate vast quantities of pollutants into the
environment from industrial processes and motor vehicles. In comparison with developing countries,
wealthy nations provide better access to medical care and are better able to finance pollution controls.
6
7
In the developing world, the pursuit of natural resources has caused widespread deforestation of tropical
rain forests and destruction of wildlife habitat. Although these two issues have been the focus of much
publicity, less widely publicized environmental hazards such as water contamination, air pollution,
9
unsanitary food, and crowding take a steep toll in both morbidity and mortality in developing countries.
One region of the world that at present confronts ser …
Purchase answer to see full
attachment
Recent Comments