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

OTHER ORGANISMS, OTHER IDEAS

In environmental toxicology the selection of an invertebrate test organism and test chemical are often closely inter-related.  Chemicals that are relevant to terrestrial/soil ecosystems, for example, might be tested using commonly available invertebrates such as earthworms, pillbugs, insect larvae, or nematodes.  Tests with chemicals that are relevant to freshwater ecosystems might utilize aquatic invertebrates such as water fleas, ostracods, copepods, hydra, planaria, snails, or amphipods (scud).  The effect that is tested might have special ecological relevance to predator avoidance, food acquisition, ability to react to stimuli, or ability to locomote.  Behavioral effects could be quantified using some defined scoring system, or effects could be analyzed using videotape playback.

Another approach to environmental toxicity is collection and testing of soil or water samples from real-world sites where contamination is suspected.  Water samples from a site may be used in laboratory toxicity tests and effects may be compared to those in control groups as well as to groups treated with concentrations of a pure chemical which is the suspected contaminant in the water samples.  Such experiments utilize invertebrates as a true “bioassay” organisms (see Glossary).   In cases of soil samples, organisms could be exposed to water extractions (leachates) derived from soil samples.

For toxicity testing relating to human health concerns, attempts should be made to match the kinds of effects that might be expected in humans (say, neurotoxicity effects or developmental effects) with organisms in which similar effects might be present and readily testable.