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Chapter Introduction

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CHAPTER 11

Environmental Health, Risk, and Toxicology

(fotog/Getty Images)

Central Question: What is the relationship between the environment and human health and how can we manage that relationship?

SCIENCE

Describe the toxic substances and pathogens in the environment and their effects on humans.

ISSUES

Explain the environmental and human health consequences of exposure to toxic substances and pathogens.

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SOLUTIONS

Discuss how we might assess risk and deal with toxic substances and pathogens in our everyday lives.

Chemical Spill on the Elk River

A toxic leak highlights how little we know about the numerous hazardous substances that affect human health and the environment.

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(AP Photo/Steve Helber)

Workers inspect an area where a toxic chemical that leaked from storage tanks contaminated the Elk River near Charleston, West Virginia, in January 2014. In the aftermath of the spill, which polluted domestic water supplies, residents of Charleston lined up to fill containers with potable water.

(AP Photo/Steve Helber) (Ty White/The New York Times/Redux)

In the mid-morning of January 9, 2014, residents in Charleston, the sleepy capital of West Virginia, noticed a sweet, licorice smell in the air. It wasn’t until 5:45 P.M. that the regional water utility began telling customers to avoid drinking, cooking, or washing with the water. One mile upstream of the city, on the banks of the Elk River, a rusty, storage tank owned by a company called Freedom Industries had leaked as much as 7,500 gallons of a chemical used to process coal. Over the next 24 hours, some 700 residents had contacted poison control, complaining of rashes and nausea. Fourteen were hospitalized.

Like many industrial chemicals used widely in the United States, little was publicly known about the toxicity of this chemical, 3-methylcyclohexanemethanol (MCHM). Under the Toxic Substances Control Act, which was passed in 1976, the U.S. Environmental Protection Agency (EPA) can test chemicals that pose a health risk—but only after those chemicals have shown evidence of harm. The 62,000 chemicals that were already on the market at the time the law was passed were exempted from regulation, and, of the 21,000 chemicals registered since then, only 15% have included health-and-safety data. Data on these new chemicals are often hidden from the public because companies argue they contain confidential business information.

On January 13, four days after the spill, officials lifted the water advisory. The little data that existed on MCHM indicated that drinking it could harm the liver and kidneys at high doses, but no one really knew for sure how exposure would affect people in the months or years to come. Nevertheless, the incident revealed how environmental hazards, when unchecked by regulation, can affect our health and well-being.

environmental health An area of research and action that assesses and attempts to mitigate the physical, chemical, and biological factors in the environment that impact human health.

Much of this book is concerned with the health of the environment—that is, the condition of the environment itself or some part of it—for instance, whether a wetlands ecosystem is clean, productive, and sustainable. In this chapter, we look at the related but distinct issue of environmental health, which refers specifically to human health and safety and the way the environment—both natural and human-created aspects—affects them. This brings us to the Central Question of this chapter.

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“If we are going to live so intimately with these chemicals—eating and drinking them, taking them into the very marrow of our bones—we had better know something about their nature and their power.”

Rachel Carson, Silent Spring

Central Question

What is the relationship between the environment and human health and how can we manage that relationship?