Volume 14, Number 6 • November-December 1996

Why Are Toxics So Difficult?

At least since the large EPA study of the Chesapeake Bay in the early 1980s described toxic chemicals as a threat to the Bay's health, scientists have struggled to understand the impact of various contaminants on the Chesapeake. The issue remains a difficult one.

Analytical Tools and Methods?

Researchers have been limited by their ability to detect contaminants in tiny amounts and mixed in with other compounds. Recent improvements in technology have allowed researchers to analyze samples with greater accuracy, and to identify smaller and smaller amounts of contaminants.
Previously, researchers were not able to track early biological effects of contaminants, and so could not witness what is generally the first response of an organism to a toxic threat. With new genetic and molecular tools this is now possible.

Experimental Design

Researchers must design complex experiments that will allow them to isolate the effects of contaminants. This can be extremely difficult because the levels of contaminants range from trace amounts to major spills and because the ecosystem is so complex.
Scientists must be able to account for differing forms or "species" of metals and other contaminants - these forms may change, depending on a number of physical, chemical and biological factors.

Making Connections

Scientists must design ways of applying results obtained in the laboratory, where they can control conditions, to the open environment, where conditions are much more chaotic.
Researchers face a difficult challenge in relating the behavior of contaminants in the environment to the effects they observe; linking environmental effects with human health issues can prove especially difficult.

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