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

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

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

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)

Dose Response Curve Dose-Response Relationships

Types of Effects  Local  Systemic  Cumulative  Poisoning

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

Types of Effects  Systematic –The toxic substance has been absorbed and distributed throughout the body

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

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

Factors Affecting Toxicity  Rate of Entry and Route of Exposure  Age  State of Health  Previous Exposure  Environmental Factors  Host Factors

Routes of Entry  Percutaneous  Inhalation  Oral  Ocular

Categories and Classification  Gases and Vapors  Aerosols  Pulmonary Irritants  Asphyxiants  Primary Anesthetics

Categories and Classification  Hepatoxic Agents  Nephrotoxic Agents  Neurotoxic Agents  Agents Attacking Hematopoietic System  Agents Damaging the Lungs  Carcinogens

Categories and Classification  Mutagens  Teratogens  Sensitization

Mechanisms of Toxicity

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

Conclusion  Questions?  Comments? Thank you for your attention & participation