Categories, Characteristics and Sources
Chemical Agents
Michael Bisesi, PhD, REHS, CIH
Senior Associate Dean, College of Public Health
Professor & Chair (interim), Environmental Health Sciences
Learning Objectives
♦ Summarize the distinctions between and among
categories of materials and agents
♦ Describe the categories and primary hazards of
chemical materials/agents
♦ Provide examples of major sources chemical
materials/agents
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•
. . . First, the general categories
of materials or agents:
• Chemical:
•
•
•
•
Toxic
Flammable/Explosive
Corrosive
Reactive/Explosive
• Biological:
• Infectious
• Radiological:
• Toxic
• also, characterized as labile vs. recalcitrant to
decay . . . putrescible or not . . .
Let’s Focus on Category
of
“Chemical” Agents . . .
And, the Associated
Subcategories
Chemicals . . . Appear in various
categories and forms
Chemicals: Toxic
Substances (e.g. metals/solvents/pesticides…)
that may interact with biomacromolecules (i.e.
proteins; nucleic acids (DNA); carbohydrates;
lipids), cells, tissues and organs within the
human body and other organisms resulting in
potential adverse biochemical and physiological
responses (i.e. illness/death). . .
Chemicals: Flammable
Substances (e.g. gasoline/wood/paper…) that
act as a fuel ("reducing agent") in the presence
of an ignition source (i.e. flame; heat; spark) plus
air (specifically oxygen as “oxidizing agent") and
will burn. . .
Generate heat plus toxic chemical products. . .
Chemicals: Reactive
Substances and mixtures (e.g. strong oxidizers/
strong reducers) that are extremely unstable:
- may enter a rapid/violent combustion
reaction resulting in intense dissipation
of heat
explosion
- release toxic by-products
Chemicals: Corrosive
Substances (e.g. acids/alkalines) that induce
tissue damage and sever irritation/burns due
to interaction with water in tissues
. . . capable of corroding steel
General Compositional
Characteristics of
Chemical Agents
Dr. Michael S. Bisesi
Chemical Agents
• Chemical Agents
– Inorganic (e.g. Metals;
Nitrites/Nitrates;…)
– Organic (e.g. Solvents; Pesticides;…)
Classification and Composition:
Natural and Anthropogenic
 Natural
vs. Synthetic (Anthropogenic)
 Inorganic
vs. Organic
Major Elemental Components
(“CHNOPS”)
 >99%
of elements in living organisms
– Carbon
– Hydrogen
– Nitrogen
– Oxygen
– Phosphorous
– Sulfur
Composition of Natural
Organic Matter
 Major
elements involved:
– C H N O P S K Ca Fe Mg Na Cl
 Major
Molecules and Molecular Compounds:
– N2 O2 CO2 NaCl H2O NO2 SO2 CH4 NH3 H2S
...
Inorganics
 Elements
 Non-Carbon*
Molecules and
Molecular Compounds:
– Hydrides
– Oxides
– Salts
. . . *Except carbon monoxide, carbon
dioxide, carbonates . . .
Organics: Aromatics
 Foundational
Benzene ring C6H6
– Mono– Poly– Heterocyclic-
Organics: Aliphatics
 Acyclic
– Alkanes (C-C)
– Alkenes (C=C)
– Alkynes (C C)
 Cyclic
– Cycloalkanes
– Cycloalkenes
– Cycloalkynes
Major Biomacromolecules
 Monomers
form polymeric Structures
– Proteins (amino acid monomers)
– Carbohydrates (sugar monomers)
– Nucleic Acids (nucleotide monomers)
– Lipids (glycerol; phosphate)
– Lignins (phenolic monomers)
 Monomers
. . . unit
 Oligomers . . . unit-unit-unit
 Polymers . . . unit-unit-unit-unit-unit-unit-unit-
Sources
of
Chemical Agents
in Various Settings
for Various Uses
Dr. Michael S. Bisesi
Outdoor and Indoor Sources
• Manufacturing Industries
• Service Industries
• Agriculture
• Mining
• Vehicles
• Combustion Sources
• Residential Dwellings
• Natural emissions and transformations
• etc.
“Ambient” Environment . . .
Air - Surface Water - Ground Water – Soil - Food
“Advancing Knowledge. Improving Life.”
“Workplace and Residential” Environments
“Advancing Knowledge. Improving Life.”
“Miscellaneous Fuels, Paints, Cleaning Agents,
Cosmetics, Grooming Agents, Pesticides,
Plants, Food/Beverages, Drugs, etc.
“Advancing Knowledge. Improving Life.”