Download Chapter 20 Study Guide Main Ideas Toxic chemicals from both

Chapter 20 Study Guide
Main Ideas
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Toxic chemicals from both natural sources and human activities that pollute air, soil, water and food may
damage human health.
Toxicology is used to determine how poisonous a substance is.
After an outbreak of an illness occurs, epidemiologists attempt to find its origin and try to find ways to
prevent future epidemics.
Most pollutants occur naturally.
Improperly disposed of wastes may leak hazardous pollutants into the environment.
Most diseases that have an environmental component are caused by pathogen.
The environment provides breeding grounds for pathogens and for their secondary hosts and vectors.
The transmission of many infectious diseases includes water. We increase the areas where organisms that
carry these diseases can reproduce when we create irrigation canals and inadequate sewage systems.
Environmental changes that help spread infections disease include global warming and the spread of
suburbs and farmland.
Many emerging diseases are caused by pathogens that have made cross-species transfers from animals to
humans.
Vocab
Define
Toxicology
The study of the harmful effects of substances on organisms
Dose
The amount of a harmful chemical to which a person is exposed to
DoseResponse
curve
Epidemiology
The relative effect of various doses of a drug or chemical on organism or organisms as determined
by experiments.
Riskassessment
Particulates
An estimate of the risk posed by an action or substance
Pathogen
Organisms that cause disease
Host
An organism in which a pathogen lives all or part of its life.
Vector
Organisms that transmit diseases to people
The study of the spread of disease
Particles in the air that is small enough to breathe into the lungs.
1. List five pollutants, their sources, and their possible effects on human health. PCBs are found in
electrical transformers and cause learning problems. Organophosphate pesticides are found on
and near crop fields and cause nerve damage. Particulates come from various sources (dust,
pollen and combustion), and can affect lung functions. Heavy metals occur in some rocks and
soil and can cause nerve damage. Radon comes from granite bedrock and can cause cancer
2. Explain how scientists use toxicology and epidemiology. Epidemiologist use information from
toxicological studies to determine types of pollutants that may be causing the rapid spread of
disease.
3. Explain how pollution can come from both natural sources and human activities. Pollution can
come from natural sources such as volcanoes and dust storms. Human sources of pollution
include domestic animal wastes in drinking water and chemical pollution from industries.
4. Describe the relationship between waste, pollution and human health. Improper disposal of
waste created pollution that can then affect human health. Ex. Factories not getting rid of their
waste properly.
5. Explain why the environment is an important factor in the spread of cholera. Cholera is
transmitted to humans through polluted sources in the environment.
6. List two changes to the environment that can lead to the spread of infectious diseases. Soil
erosion, the creation of irrigation canals, antibiotic use, habitat destruction which put humans in
great contact with wild animals.
7. Explain what scientists mean when they say that certain viruses are emerging. A virus that was
unknown in the recent past but that now threatens humans.