BASIC ENVIRONMENTAL TOXICOLOGY

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BASIC ENVIRONMENTAL TOXICOLOGY
What is there that is not poison? All things are
poison and nothing without poison. Solely the
dose determines a thing is not a poison.
Paracelsus 1500 AD (from Philosophia
Magna Brickmann, Cologne, 1567)
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DOSE - RESPONSE RELATIONSHIP

• What is DOSE?
• - The total amount of the hazard that actually
  enters the body relative to the individuals body
  weight
• The right dose differentiates a poison and a
  remedy
• The bodys response to chemicals depends on the
  dose received

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Terminologies in Toxicology

• Toxicology
• Hazard
• Risk
• Exposure
• Toxicity
• Toxin
• Toxicant

• A. Something that can harm the health of humans
  or the environment
• B. Toxic substances produced naturally
• C. Measure of how dangerous a chemical is
• D. The likelihood that a harmful consequence may
  occur
• E. The total amount of a chemical that comes into
  direct contact with the body
• F. The study of harmful effects of chemicals on
  living things
• G. Toxic substances produced or by-product of
  human activities

F
A
D
E
C
B
G
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ENVIRONMENTAL CONCENTRATION OF TOXICANTS

• ENVIRONMENTAL CONCENTRATION
• Is the concentration of an agent in an
  environmental medium
• Refers to the agents presence in that
  particular medium expressed quantitatively

• 2 Major Concepts
• Bioaccumulation
• Biomagnification

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BIOACCUMULATION

YOUNGER OLDER
 The green fill represents contaminants
The cellular mechanism which involves absorption
and storage of molecules within an organism
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BIOMAGNIFICATION

• Ex. DDT (dichloro-diphenyl-trichloroethane)
• It occurs when the toxic burden of a large
  number of organisms at a lower trophic level is
  accumulated and concentrated by a predator in a
  higher trophic level

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CLASSIFICATION OF TOXIC CHEMICALS

• 1. IRRITANTS - Corrosives damages tissues or
  materials
• 2. ASPHYXIANTS - Interferes with Oxygen uptake
  distribution
• 3. NARCOTICS or ANESTHETICS - Depresses the CNS
• 4. NEUROTOXINS - specifically attacks the nerve
  cells extremely
• toxic fast acting
• 5. MUTAGENS - Alters genetic material in cells
• 6. TERATOGENS - Specifically causes abnormalities
  during embryonic
• growth development
• 7. CARCINOGENS - Induces cancer malignant
  tumors
• 8. SYSTEMIC POISONS - Produces internal damages
  to organs

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IRRITANTS
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Examples of asphyxiating gases are nitrogen
(N2), helium (He), neon (Ne), argon (Ar), methane
(CH4), propane (CH3CH2CH3), and carbon dioxide.
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NARCOTICS OR ANESTHETICS Lidocaine Lidocaine is
a common anesthetic used for local and regional
anesthesia. Sevoflurane Sevoflurane is a
rapid-acting, inhaled general anesthetic, which
is used to put people to sleep and keep them
asleep during a surgical procedure. Propofol Pro
pofol is an intravenous general anesthetic, which
is commonly used to put people to sleep and
maintain anesthesia.
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NEUROTOXINS Arsenic, Ammonia, , Lead, Ethanol,
n-Hexane, Nitric oxide MUTAGENS X-rays, uv
rays