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Environmental Science
A Need for Living Sustainably

v1.0 Joseph Shostell

Chapter 1 Introduction to Environmental Science: Sustainability

Case Study: Grasshopper Effect

In 1987, Canadian scientist Dr. Eric Dewailly was researching the presence of environmental toxic substances in human breast milk within Quebec province. As part of his study, he requested breast milk samples from Nunavik, one of the most isolated areas in Quebec. High above the Arctic Circle, Nunavik was far from cities, factories, and industries and the pollution they generate. Surprisingly, the analysis indicated extremely high concentrations of toxins among the Nunavik samples. Worried there was a mistake or the samples had been contaminated, Dr. Dewailly ran the samples again. The second analysis confirmed the first: there were high concentrations of toxic substances in the breast milk of women living in the Arctic region. How could this be?

Figure 1.1

The vast, pristine-looking Arctic is a reservoir of environmental toxic substances that originated from lower, warmer latitudes. The highest concentrations of the substances are found in apex predators of the food chain—polar bears and people. A) A mother polar bear with her cub moving across ice floes; B) An Arctic settlement.

In box on the left labeled A, two polar bears are shown, one an adult and one a cub. They are standing on an ice sheet that is surrounded by water. In box on right labeled B, a seaside Arctic village is shown in the foreground with water and snowcapped mountains in the background.

The sparsely populated and seemingly pristine Arctic has some of the highest concentrations of deadly environmental toxic substances on Earth. These substances, including the persistent organic pollutants dichlorodiphenyltrichloroethane (DDT), toxaphene, chlordane, polychlorinated biphenyls (PCBs), and the heavy metal mercury, do not originate in the Arctic; rather, they are carried by air currents from lower, warmer latitudes. Collectively, the toxic substances are called persistent organic pollutants (POPs) because unlike most organic compounds they do not readily degrade in the environment. POPs can move over long distances in a series of evaporation and condensation events (or “hops”)—essentially riding parcels of air. As air warms near Earth’s surface, it picks up evaporated toxins from the soil, then expands, becomes less dense, and consequently rises and moves toward a polar region. Within the northern hemisphere, air parcels move in the direction of the North Pole (Arctic), whereas in the southern hemisphere, the air parcels end up in the South Pole (Antarctica). Not all of these toxic substances evaporate from the soil; some are released from industrial and power plant chimneys directly into the atmosphere. For example, when we combust coal, we convert mercury from solid to gas form and consequently make it mobile. Once airborne, mercury hops like a grasshopper, and in the final jump, settles on Arctic land and waters alike. On land, mercury and other persistent organic pollutants contaminate lichens, shrubs, mosses, and grasses that serve as food for Arctic animals such as caribou. As the toxins move up the , they become more concentrated (). Therefore, tissues of caribou have a higher concentration of the toxins than the tissues of the plants they eat; tissues of Inuits, the Indigenous population who hunt and eat caribou, have an even higher concentration. In the ocean, the toxic substances are taken up () by algae (small plant cells) and bacteria and then biomagnify as they move up the food chain to zooplankton, fish, seals, and polar bears (see Figure 1.1). Inuits are the apex predator of this system because they hunt seals and polar bears.

These environmental toxic substances are a serious concern to Inuits and all peoples exposed to them, because they negatively affect human health. Mercury, for example, damages the nervous, circulatory, and immune systems. Fat-soluble toxic substances such as mercury concentrate in fat tissue and are released in breast milk and transferred to newborns. Persistent organic pollutants are linked to hormonal disruptions, changes in the reproductive system, neurological and learning disabilities, and cancer (Bonefeld-Jørgensen et al. 2017).

As you can see, the Arctic has, more or less become a sink for environmental toxic substances produced in other parts of the world. Deciphering the issue was a complex endeavor, from first detecting toxic substances within people and the environment of the Arctic, to understanding associated health risks, to identifying their sources hundreds or thousands of kilometers away, to determining how they are transferred geographically and how they move through the food chain. Environmental scientists, in collaboration with Arctic peoples, health scientists, and climatologists, pieced together the complete story, and this information was put forward to the United Nations to find a solution. No matter the size of the environmental issue, history has chronicled how the actions of individuals and groups of people have led to positive environmental change. On May 22, 2001, in Stockholm, Sweden, representatives from 152 countries discussed the presented information and then signed an international treaty to eliminate or reduce the release of persistent organic pollutants with the intention of simultaneously protecting the environment and people. The treaty was entered into force on May 17, 2004, and the list of POPs identified in the treaty has expanded since that time.