Ensci 181

• what is the traditional definition of Toxicology?

  the science of poisons
• descriptive definition of toxicology


  the study of the adverse effects of chemicals or physical agents on living organisms
• The adverse effect of toxic substance in the environment can be expressed - and -.

  Quantitatively and Qualitatively
• example of quantitative effect

  number of egg hatched or # mortality
• example of qualitatively


  change of color and texture
• Toxicology began with

  early cave dwellers recognized poisonous plants and animals and used their extracts for hunting or in warfare.
• Substance that produce adverse biological effects of any nature

  Toxicants
• Specific proteins produced by living organisms (mushroom toxin or tetanus toxin)

  Toxins
• Toxicant can be

  Biological

  Chemical

  Physical
• Toxicants that can cause immediate death or illness when experience in very small amount.

  Poisons
• When a tiny amount is harmful, the chemical is considered to be

  highly toxic
• When a very large amount of the chemical can cause damage, the chemical is considered to be practically


  non-toxic
• True or False

  All chemicals can cause harm?

  True
• The - of a substance is its ability to cause harmful effects.

  Toxicity
• The toxicity of a substance depends on three factors


  its amount/concentrations/dose.

  extent to which the substance is absorbed by the body or exposure

  its reaction and interaction or effect.
• is a relative property of a chemical which refers to its potential to have a harmful effect on living organism.

  toxicity
• is a science that describes the effect of toxic substances or agents on organisms, especially on populations and communities in an ecosystem.

  Ecotoxicology
• The core of ecotoxicology lies in two main areas:


  the study of the environment, with the origin in the science of ecology.

  the study of the interactions of the toxic chemicals with individual living organisms, the science of toxicology
• Any unit that includes all organisms living together in an area interacting with the physical environment

  ecosystem
• study the immediate effects of s toxic substance on individual and species.

  Ecotoxicologists
• also study what happens to the toxic substance themselves

  Ecotoxicologists
• the term ecotoxicology was coined from the word


  ecosystem and toxicology in 1969 first used by professor R. Truhaut.