CHAPTER 6:
ENVIRONMENTAL
HAZARDS &
HUMAN HEALTH
Environmental Toxicology
What is Environmental Toxicology?
◦ Environmental toxicology is the scientific study of the
health effects associated with exposure to toxic chemicals)
occurring in the natural, work, and living environments.
The term also describes the management of environmental
toxins and toxicity, and the development of protections for
humans and the environment.
The ATSDR 2013 Substance Priority List. The lists top 20 substances, in order of priority, which are
determined to pose the most significant potential threat to human health. This priority list is not a list
of “most toxic” substances but rather a prioritization of substances based on a combination of their
frequency, toxicity, and potential for human exposure at various sites.
RANK NAME
1 ARSENIC
2 LEAD
3 MERCURY
4 VINYL CHLORIDE
5 POLYCHLORINATED BIPHENYLS
6 BENZENE
7 CADMIUM
8 BENZO(A)PYRENE
9 POLYCYCLIC AROMATIC
HYDROCARBONS
RANK NAME
10 BENZO(B)FLUORANTHENE
11 CHLOROFORM
12 AROCLOR 1260
13 DDT, P,P’
14 AROCLOR 1254
15 DIBENZO(A,H)ANTHRACENE
16 TRICHLOROETHYLENE
17 CHROMIUM, HEXAVALENT
18 DIELDRIN
19 PHOSPHORUS, WHITE
20 HEXACHLOROBUTADIENE
Routes of Exposure to Chemicals
Breathing (inhalation): Breathing in chemical gases, mists, or dusts that are in the
air.
Skin or eye contact: Getting chemicals on the skin, or in the eyes. They can damage
the skin, or be absorbed through the skin into the bloodstream.
Swallowing (ingestion): This can happen when chemicals have spilled or settled
onto food, beverages, cigarettes, beards, or hands.
What Forms do Chemicals Take?
◦ Chemical substances can take a variety of forms. They can be in the
form of solids, liquids, dusts, vapors, gases, fibers, mists and fumes.
The form a substance is in has a lot to do with how it gets into your
body and what harm it can cause. A chemical can also change
forms. For example, liquid solvents can evaporate and give off
vapors that you can inhale. Sometimes chemicals are in a form that
can’t be seen or smelled, so they can’t be easily detected.
Environmental Contaminants
The contamination of the air, water, or soil with potentially harmful
substances can affect any person or community. Contaminants are
often chemicals found in the environment in amounts higher than
what would be there naturally. We can be exposed to these
contaminants from a variety of residential, commercial, and
industrial sources. Sometimes harmful environmental contaminants
occur biologically, such as mold or a toxic algae bloom.
Classification of Environmental
Contaminants
Contaminant Definition
Carcinogen An agent which may produce cancer (uncontrolled cell growth), either by itself or in conjunction with another
substance. Examples include formaldehyde, asbestos, radon, vinyl chloride, and tobacco.
Teratogen A substance which can cause physical defects in a developing embryo. Examples include alcohol and cigarette
smoke.
Mutagen A material that induces genetic changes (mutations) in the DNA. Examples include radioactive substances, x-
rays and ultraviolet radiation.
Neurotoxicant A substance that can cause an adverse effect on the chemistry, structure or function of the nervous system.
Examples include lead and mercury.
Endocrine A chemical that may interfere with the body’s endocrine (hormonal) system and produce adverse
disruptor developmental, reproductive, neurological, and immune effects in both humans and wildlife. A wide range of
substances, both natural and man-made, are thought to cause endocrine disruption, including pharmaceuticals,
dioxin and dioxin-like compounds, arsenic, polychlorinated biphenyls (PCBs), DDT and other pesticides, and
plasticizers such as bisphenol A (BPA).
An Overview of Some Common Contaminants
1. Arsenic
- is a naturally occurring element that is normally present throughout our environment in
water, soil, dust, air, and food.
2. Mercury
- is a naturally occurring metal, a useful chemical in some products, and a potential health
risk.
3. Bisphenol A (BPA)
- is a chemical synthesized in large quantities for use primarily in the production of
polycarbonate plastics and epoxy resins.
What can I do to prevent exposure to BPA?
• Don’t microwave polycarbonate plastic food containers. Polycarbonate is strong and durable,
but over time it may break down from over use at high temperatures.
• Plastic containers have recycle codes on the bottom. Some, but not all, plastics that are
marked with recycle codes 3 or 7 may be made with BPA.
• Reduce your use of canned foods.
• When possible, opt for glass, porcelain or stainless steel containers, particularly for hot food
or liquids.
• Use baby bottles that are BPA free.
THANK YOU
FOR LISTENING!
