TOXICOLOGY

1
TOXICOLOGY

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

2
Definition

• Study of adverse effects of chemicals (i.e.
  poisoning) on living organisms
• Has 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

3
Dose- Response Relationship

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

4
Types of Exposures

• Acute (Short term) A single exposure lasting
  less than 24 hours
• Chronic (Long term) Exposures are essentially
  for the lifetime of the species
• Subchronic Repeated exposures of less than a
  lifetime (e.g. 3 months)

5
Dose Response Curve
Dose-Response Relationships                     
                                                  
                                                 
6
Types of Effects

• Local
• Systemic
• Cumulative
• Poisoning

7
Types of Effects

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

8
Types of Effects

• Systematic
• The toxic substance has been absorbed and
  distributed throughout the body

9
Types of Effects

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

10
Types of Effects

• Poisoning
• A toxic substance is absorbed and distributed by
  the blood stream throughout the body
• Absorption reaches a point where it causes
  impairment of physiological function

11
Factors Affecting Toxicity

• Rate of Entry and Route of Exposure
• Age
• State of Health
• Previous Exposure
• Environmental Factors
• Host Factors

12
Routes of Entry

• Percutaneous
• Inhalation
• Oral
• Ocular

13
Categories and Classification

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

14
Categories and Classification

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

15
Categories and Classification

• Mutagens
• Teratogens
• Sensitization

16
Mechanisms of Toxicity
17
Summary

• Definition
• Dose Response
• Types of Exposure
• Types of Effects
• Factors Affecting Toxicity
• Categories and Classification

18
Conclusion

• Questions?
• Comments?
• Thank you for your attention participation