Volume 50, Number 1, December 2003:
A Toxicology Primer for Student Inquiry: Biological Smoke Detectors

Text-only version

ISSUE HOME PAGE

ABOUT THIS ISSUE
- about KSN
- about the author
- acknowledgements

IN THIS ISSUE
- disclaimer, objectives
- "biological smoke detectors"
- purpose of invertebrate toxicity testing
- lethal and sublethal effects
- some wormy ideas for toxicity testing
- sublethal chemical effects in lumbriculus
- selecting the chemical(s)
- safety
- exposure methods
- preliminary experiments and concentration range-finding
- final stages of toxicity testing
- typical equipment and supplies
- other organisms, other ideas
- obtaining background information
- references
- glossary of toxicological terms

A Toxicology Primer for Student Inquiry:
Biological Smoke Detectors
by Charles Drewes

PURPOSE OF INVERTEBRATE TOXICITY TESTING

Toxicity testing involves the discovery and analysis of chemical effects on organisms. Extensive toxicity testing, using many species, is needed to understand the full spectrum of biological effects of chemicals and to decrease the health risks that chemical effects pose for humans and ecosystems.  Toxicity testing is crucial for a wide variety of chemicals that are present in drugs, cosmetics, pesticides, food additives, cleansers, solvents, and industrial wastes.  Invertebrates are used in toxicity testing for one of two reasons:

(1)  Some invertebrate species may have considerable relevance to the environment.  For example, earthworms are ecologically beneficial to soil ecosystems and zooplankton are key links in aquatic food chains.  Some invertebrates may also have environmental relevance, not because they are beneficial, but because they are pests.  In either case, it is important to know if and how the presence of a chemical in the environment might affect any of these organisms.  Laboratory testing under controlled experimental conditions is an important approach to understanding and predicting possible effects of chemicals in ecosystems.

(2)  Invertebrates may provide useful insights to understanding chemical effects on human health.  This is because invertebrates share some of the same biochemical and physiological processes that exist in nearly all animals, including humans.  For example, many nerve cell functions are common to worms, insects, fish, rats, humans, etc.  Therefore, invertebrate toxicity testing may be a useful tool for understanding and detecting biological effects of chemicals at molecular, cellular, or behavioral levels in many organisms.