Botkin Environmental Science Earth as Living Planet 8th txtbk

Study Questions 209
Urban World
People
and Nature
Science
and Values
Industrial processes in urban areas concentrate potentially toxic materials
that may be inadvertently, accidentally, or deliberately released into the environment.
Human exposure to a variety of pollutants—including lead,
asbestos, particulates, organic chemicals, radiation, and noise—is often
greater in urban areas.
Feminization of frogs and other animals from exposure to human-produced,
hormonally active agents (HAAs) is an early warning or red flag that we
are disrupting some basic aspects of nature. We are performing unplanned
experiments on nature, and the consequences to us and other living organisms
with which we share the environment are poorly understood. Control
of HAAs seems an obvious candidate for application of the precautionary
principle, discussed in Chapter 1.
Because we value both human and nonhuman life, we are interested in
learning all we can about the risks of exposing living things to chemicals,
pollutants, and toxins. Unfortunately, our knowledge of risk assessment
is often incomplete, and the dose response for many chemicals is poorly
understood. What we decide to do about exposure to toxic chemicals reflects
our values. Increased control of toxic materials in homes and the work
environment is expensive. To reduce environmental hazards at worksites
in other countries, are we willing to pay more for the goods those workers
manufacture?
KEY TERMS
area sources 188
asbestos 199
biomagnification 191
carcinogen 188
contamination 188
disease 187
dose response 202
ecological gradient 205
ED-50 204
electromagnetic fields (EMFs) 199
heavy metals 191
hormonally active agents (HAAs) 196
LD-50 203
mobile sources 188
noise pollution 200
organic compounds 193
particulates 199
persistent organic pollutants
(POPs) 194
point sources 188
pollution 188
risk assessment 205
synergism 188
synthetic organic compounds 193
TD-50 204
thermal pollution 198
threshold 204
tolerance 205
toxicology 188
toxin 188
STUDY QUESTIONS
1. Do you think the hypothesis that some crime is caused
in part by environmental pollution is valid? Why?
Why not? How might the hypothesis be further tested?
What are the social ramifications of the tests?
2. What kinds of life-forms would most likely survive in
a highly polluted world? What would be their general
ecological characteristics?
3. Some environmentalists argue that there is no such
thing as a threshold for pollution effects. What do they
mean? How would you determine whether it was true
for a specific chemical and a specific species?
4. What is biomagnification, and why is it important in
toxicology?