Sustaining Lake Superior by Nancy Langston

Author:Nancy Langston [Langston, Nancy]
Language: eng
Format: epub
Publisher: Yale University Press
Published: 2017-04-10T04:00:00+00:00

SEVEN

The Mysteries of Toxaphene and Toxic Fish

THE PERSISTENT, BIOACCUMULATIVE chemical named toxaphene offers a case study on the history of toxic contamination in Lake Superior fish. How did chemicals such as toxaphene make their way into fish in the postwar era? How did governments and communities around the Great Lakes struggle to comprehend and then control these toxics? My goal is to explore the intersection of human culture with the pollutants that have made their way into water bodies—and the bodies of fish and the people who eat those fish—everywhere. Fish is a healthy source of protein that we’re encouraged to eat, yet pregnant women face wrenching choices when they wonder whether the fish on their plate might harm their developing fetus. Fatty fish provide important nutritional benefits to the mother—but the fats could be contaminated with chemicals that could harm development. These aren’t choices anyone should have to make.

In the late 1990s, Canadian scientists noticed that levels of toxaphene were rising in the fish of Lake Superior, even though the chemical had not been used near the lake for decades (see chapter 3).1 Toxaphene had been banned in 1990, yet unlike other persistent bioaccumulative toxics, its levels were not dropping. Of all the Great Lakes, Lake Superior is easily the cleanest. So why would toxaphene be highest in this particular lake, in a region where the chemical had never been produced or used in agriculture?

What might toxaphene contamination mean for one of the great recovery stories of modern conservation: the restoration of Lake Superior fisheries? Even more pressing, what might that contamination mean for Ojibwe bands trying to restore culturally significant foods such as lake trout to their diets? When researchers examined toxic levels in fish and people, it became clear that people who ate fish from the Great Lakes were accumulating significant levels of banned toxic chemicals. During pregnancy, women passed these chemicals to their developing fetuses at their most vulnerable stages of development. The legacies of the past were becoming the body burdens of future generations. Because consumption of fish is an important vector of human exposure to endocrine-disrupting chemicals, toxics are particularly controversial in Indigenous communities in the United States and Canada where levels of fish consumption are high or where chemical industries have been sited close to Indigenous reserves and food sources.

Toxaphene refers to a group of turpentine-smelling chemicals made from pine oil and chlorine—two natural chemicals that are combined into a synthetic substance. Soon after being introduced into commerce after World War II, toxaphene was found to be toxic to fish, birds, and mammals. In the late 1940s, research was published showing its toxicity, and over the next two decades, studies indicated it to be mutagenic and carcinogenic in mammals.2 After DDT was banned, toxaphene manufacturers began promoting toxaphene as a safe alternative. Research showing toxaphene’s risks had been published for decades, yet because toxaphene was made from nature’s own building blocks, customers believed it to be safer than DDT. Soon it was being

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