Glossary

Heavy metals are generally interpreted to include those metals with a specific gravity that is at least 5 times the specific gravity of water. Metals often mentioned from a toxicity standpoint include antimony, arsenic, bismuth, cadmium, cerium, chromium, cobalt, gallium, gold, iron, lead, manganese, mercury, nickel, platinum, silver, tellurium, thallium, tin, uranium and vanadium.

A herbicide is used to control a specific weed species, while leaving the desired crop relatively unharmed. Some of these act by interfering with the growth of the weed and are often synthetic mimics of natural plant hormones. Unlike pesticides, they target plant and not animal species.