Classification based on particular effects on health Types of Toxicants Classification based on particular effects on health

Carcinogens Chemicals or types of radiation Cause cancer - uncontrolled cell growth Greatest # of cancer cases is thought be related to carcinogens in cigarette smoke

Mutagens Chemicals or types of radiation Cause mutations in DNA sequence E.g. UV rays, x-rays, nitrous acids

Teratogens Chemicals Affect the development of human embryos in the womb Cause birth defects e.g. thalidomide – morning sickness pill in ‘50s cause severe birth defects.

Allergens Over-activate the immune system, causing an immune response when it is not necessary. e.g. asthma is thought to be a response to synthetic chemicals that are more prevalent in our environment.

Neurotoxins Chemical Attacks the nervous system - coordinates action and transports signals e.g. heavy metals; lead, mercury (fish), cadmium, some pesticides, chemical weapons, etc.

Endocrine Disruptors Chemicals that interfere with the endocrine system Hormone system: messenger molecules that serve vital functions; stimulate growth, development and sexual maturity, regulate brain function, appetite, sex drive, other physiology and behavior