Toxicology

• Toxicology

  The study of adverse effects of chemicals on living systems
• Harmful or adverse effects

  • Mechanisms of action and exposure to chemicals as a cause of acute and chronic illness
  • Understanding physiology and pharmacology by using toxic agents as chemical probes
  • Recognition, identification, quantification of hazards from occupational exposure to chemicals
  • Discovery of new drugs and pesticides
  • Development of standards and regulations to protect humans and the environment from adverse effects of chemicals
• Poison


  Any chemical that is toxic and can cause serious harm to the body
• What toxicologists aim to study about poisons

  • Detection of poison
  • Occurrence of poison
  • The properties of poison
  • The effects of poison
  • Treatment options for the poison
  • Regulation for the poison
• Toxicity


  Poisonous or deadly effects on the body by inhalation, ingestion, or absorption, or by direct contact with a chemical
• Toxic


  Relating to poisonous or deadly effects on the body
• Toxicant


  Any chemical that can injure or kill humans, animals, or plants; a poison produced or as a by-product of human-made activities
• Toxin


  Any poisonous substance of microbial, vegetable, or synthetic chemical origin that reacts with specific cellular components to kill cells, alter growth or development, or kill the organism
• Toxic symptom


  Any feeling or sign indicating the presence of a poison in the system
• Toxic effects


  The health effects that occur due to exposure to a toxic substance; also known as a poisonous effect on the body
• Selective toxicity


  A chemical will produce injury to one kind of living matter without harming another form of life, even though the two may exist close together
• Dose


  The actual amount of a chemical that enters the body, due to either acute (short) or chronic (long-term) exposure
• Dose-response


  The relationship between exposure and health effect, established by measuring the response relative to an increasing dose
• Threshold dose


  The dose or exposure level below which the harmful or adverse effects of a substance are not seen in a population (also known as NOAEL or NEL)
• Individual susceptibility


  Differences in types of responses to hazardous substances, between people
• Sensitive sub-population


  Persons who are more at risk from illness due to exposure to hazardous substances than the average, healthy person
• Sub-disciplines of Toxicology


  • Environmental Toxicology
  • Occupational (Industrial) Toxicology
  • Regulatory Toxicology
  • Food Toxicology
  • Clinical Toxicology
  • Descriptive Toxicology
  • Forensic Toxicology
  • Analytical Toxicology
  • Mechanistic Toxicology
  • Applied Toxicology
  • Veterinary Toxicology
• Factors determining adverse effects

  • Intrinsic toxicity
  • Dose
  • Exposure conditions
  • Response of host
• Factors that Affect Chemical Toxicity

  • Dosage: acute exposure (large single exposures) and chronic exposure (small and continuous exposures)
  • Route of Exposure: ingestion, skin absorption or inhalation
  • Species
  • Age
  • Sex
  • Health
  • Environment
  • Individual characteristics