TOXICOLOGY

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TOXICOLOGY

• Trina Redford, Industrial Hygienist
• National Naval Medical Center
• Naval Business Bldg 615, 2nd Fl.
• Philadelphia, PA

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Definition

• An innate characteristics of a chemical
  molecule.
• The potential to produce injury to living things.
• The probability that injury will occur under the
  conditions and the manners in which the substance
  is to be used.

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Dose- Response Relationship

• The toxic potency of a chemical is defined by the
  relationship between the dose(the amount) of
  chemical and the response that is produced in a
  biological system.

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Types of Exposures

• Acute- (Short term)-A single measured exposure of
  a duration less than 24 hours.
• Chronic (Long term)-Exposures are essentially
  for the lifetime of the species.
• Subchronic-repeated exposures of less than a
  lifetime.

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Dose Response Curve
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Types of Effects

• Local
• Systemic
• Cumulative
• Poisoning

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Types of Effects

• Local-the site of action takes places at the
  point of contact. The site may be skin, mucous
  membrane of the eyes,nose, mouth, throat or
  anywhere the along the respiratory or
  gastrointestinal system.

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Types of Effects

• Systematic- When the toxic substance has been
  absorbed and distributed through the body.

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Types of Effects

• Cumulative Effects-Over period of time , the
  material is only partially excreted, the
  remaining quanties are gradually accumulated.
• The retained toxic compounds accumulates and
  becomes great enough to cause pathological
  response.

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Poisoning

• Toxic substance is absorbed into the body and
  distributed through the body by means of blood
  stream.
• Absorption reaches a point where it caused
  impairment of physiological function.

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Factors Affecting Toxicity

• Reserve Capacity
• Storage
• Age
• State of Health
• Previous Exposure
• Environmental Factors
• Host Factors

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Routes of Entry

• Percutaneous
• Inhalation
• Oral
• Ocular

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Catergories /Classification

• Gases and Vapors
• Aerosols
• Pulmonary Irritants
• Asphyxiants
• Primary Anesthetics

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Catergories/Classification

• Hepatoxic Agents
• Nephrotoxic Agents
• Neurotoxic Agents
• Agents attacting Hematopoietic System
• Agents Damaging the Lungs
• Carcinogens

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Catergories /Classification

• Mutagens
• Teratogens
• Sensitization

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Mechanisms of Toxicity
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Summary

• Definition
• Dose Response
• Types of Exposure
• Types of Effects
• Factors Affecting Toxicity
• Catergories/Classification