Page 404 - Environment: The Science Behind the Stories

Reviewing Objectives

You should now be able to: Discuss the study of hazards and their effects,
including wildlife toxicology, case histories,
epidemiology, animal testing, and dose-response
Explain the goals of environmental health and identify analysis
major environmental health hazards
• Studies of wildlife can inform initiatives to improve
• Environmental health seeks to assess and mitigate envi- human health. (pp. 392–393)
ronmental factors that adversely affect human health and
ecological systems. (p. 378) • In case histories, researchers study health problems in indi-
vidual people. (p. 393)
• Environmental health threats include physical, chemical,
biological, and cultural hazards. (pp. 378–379) • Epidemiology involves gathering data from many peo-
ple over long-term periods and comparing groups with
• Disease is a major focus of environmental health. We have and without exposure to the factor being assessed. (pp.
successfully fought some infectious diseases, but others 393–394)
are spreading. (pp. 380–384)
• In dose-response analysis, scientists measure the response
• Sanitation, clean water, food security, education, and of test animals to various doses of the suspected toxicant.
access to medical care are strategies to enhance environ- (pp. 394–395)
mental health. (pp. 383–384)
• Toxicity may be influenced by synergistic interactions
• Toxicology is the study of poisonous substances. among hazards. (p. 395)
(p. 384)
• Unconventional dose-response curves from endocrine-
• Several major environmental hazards (cigarette smoke, radon, disrupting substances are causing toxicologists to reassess
asbestos, lead, and PBDEs) exist indoors. (pp. 384–385)
some of their assumptions and methods. (pp. 395–397)

Describe the types of toxic substances in the
environment, the factors that affect their toxicity, and Evaluate risk assessment and risk management
the defenses that organisms possess against them
• Risk assessment involves quantifying and comparing risks
• Toxicants may be natural as well as synthetic, and thou- involved in different activities or substances. (pp. 398–399)
sands of synthetic substances exist in our environment and • Risk management integrates science with political, social,
in our bodies. (pp. 385–387)
and economic concerns in order to design strategies to min-
• Toxicants include carcinogens, mutagens, teratogens, imize risk. (pp. 399–400)
allergens, pathway inhibitors, neurotoxins, and endocrine
disruptors. (pp. 387–388) Compare philosophical approaches to risk and how
• Organisms possess defenses against some toxins they relate to regulatory policy
(pp. 388–389) • An innocent-until-proven-guilty approach assumes that a
• Toxicity or strength of response may be influenced by the substance is safe unless shown to be harmful. This puts the
nature of exposure (acute or chronic) and individual varia- burden of proof on the public to prove that a substance is
tion. (p. 389) harmful. (p. 400)
• A precautionary approach assumes that a substance may
Explain the movements of toxic substances and how be harmful unless proven safe. This puts the burden of CHAPTER 14 • Envi R onm E n TA l H EA lTH A nd T o xi C ology
they affect organisms and ecosystems proof on the manufacturer to prove that a substance is safe.
• Toxic substances may travel long distances through the (p. 401)
atmosphere or may concentrate in and move through sur- • The EPA, CDC, FDA, and OSHA are responsible for reg-
face water and groundwater. (p. 390) ulating environmental health hazards under U.S. policy.
• Some chemicals break down very slowly and thus persist in (p. 401)
the environment. (pp. 390–391) • European nations take a more precautionary approach than

• Some toxic substances bioaccumulate and move up the does the United States when it comes to testing chemi-
food chain, poisoning consumers at high trophic levels cal products, as shown by a comparison of REACH and
through the process of biomagnification. (pp. 391–392) TSCA. (pp. 401–402)
• Toxic substances impair ecosystem services by affecting • The Stockholm Convention aims to ban 12 persistent
organisms that provide these services, such as honeybee organic pollutants. (p. 402)
pollinators. (pp. 392) 403

M14_WITH7428_05_SE_C14.indd 403 12/12/14 3:04 PM