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Toxicology
I
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What is Toxicology?
B
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Sub-Disciplines of Toxicology
II
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Heavy Metals
B
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Radiation and Radioactive Materials
D
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Pesticides
F
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Mushroom toxins
H
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Animal Toxins
J
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General Classifications of Interest to Communities
III
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Electronic Databases
A
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What are harmful or adverse effects? Harmful or adverse effects
are those that are damaging to either the survival or normal function of
the individual
...
The toxicity depends on a variety of factors: dose, duration and route of exposure,
shape and structure of the chemical itself, and individual human factors
...

What is a Toxicant? A toxicant is any chemical that can injure or
kill humans, animals, or plants; a poison
...
For example, dioxin (2,3-7,8tetrachlorodibenzo-p-dioxin {TCDD}), produced as a by-product of
certain chlorinated chemicals, is a toxicant
...
If the second case is true, such toxic substances are referred to as
toxicants, rather than toxins
...
A toxin is any poisonous
substance of microbial (bacteria or other tiny plants or animals), vegetable, or synthetic chemical origin that reacts with specific cellular
components to kill cells, alter growth or development, or kill the organism
...


What are Toxic Effects? This term refers to the health effects that
occur due to exposure to a toxic substance; also known as a poisonous
effect on the body
...

How Does Toxicity Develop? Before toxicity can develop, a substance must come into contact with a body surface such as skin, eye or
mucosa of the digestive or respiratory tract
...

What is a dose? The dose is the actual amount of a chemical that
enters the body
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An acute exposure occurs over a very
short period of time, usually 24 hours
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The amount of
exposure and the type of toxin will determine the toxic effect
...
This relationship is important
in determining the toxicity of a particular substance
...
Usually, the larger or more intense the dose, the greater the response, or the effect
...
”

What is the threshold dose? Given the idea of a dose-response,
there should be a dose or exposure level below which the harmful or
adverse effects of a substance are not seen in a population
...
This dose is also referred to as
the no observed adverse effect level (NOAEL), or the no effect
level (NEL)
...
However, for
substances causing cancer (carcinogens), no safe level of exposure
exists, since any exposure could result in cancer
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Each person is unique (because our genes differ in approximately 0
...
Exposure in one person may have no effect, while
a second person may become seriously ill, and a third may develop
cancer or toxicity symptoms
...
These
persons usually include the very young, the chronically ill, and the
very old
...
Depending on the type of contaminant, other factors (e
...
,
age, weight, lifestyle, sex) could be used to describe the population
...
The measurement of the time course of absorption, distribution, biotransformation,
and excretion of toxic compounds (sometimes referred to as pharmacokinetics)
...

What are “toxicogenetics and toxicogenomics?” Toxicogenetics
describes consideration of stable and heritable alterations in the genome that are able to influence the relative susceptibility of an individual (or group of individuals) to the adverse health effects that may result from exposure to an exogenous material
...
The two disciplines are
linked; polymorphisms that alter biological function may change the
spectrum of genes regulated in response to a toxicant
...
In the future, toxicogenomic data from global gene-expression
profiling and toxicogenetic data from genome-wide single nucleotide
polymorphism (SNP) mapping will facilitate the identification of
genes and pathways that determine relative susceptibility to potentially
toxic substances
...
The Field of Toxicology
Toxicology addresses a variety of questions
...
Toxicology is also used in laboratory experiments on animals to establish dose-response relationships
...

C
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It also deals
with toxic substances that enter bodies of waters such as lakes,
streams, rivers, and oceans
...

Occupational (Industrial) Toxicology is concerned with health effects from exposure to chemicals in the workplace
...
Occupational diseases caused by industrial
chemicals account for an estimated 50,000 to 70,000 deaths, and
350,000 new cases of illness each year in the United States
...
The standard is the level of a chemical that a person can be exposed to without any harmful health effects
...
During processing, a number of substances
may be added to food to make it look, taste, or smell better
...
All of these additives are studied to determine if
and at what amount, they may produce adverse effects
...
Almost 30% of the American people have some food allergy
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In addition, toxic substances
such as pesticides may be applied to a food crop in the field, while
lead, arsenic, and cadmium are naturally present in soil and water, and
may be absorbed by plants
...


Clinical Toxicology is concerned with diseases and illnesses associated with short term or long term exposure to toxic chemicals
...

Descriptive Toxicology is concerned with gathering toxicological
information from animal experimentation
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The United States Environmental Protection Agency (EPA), the Occupational Safety and Health Administration (OSHA), and the Food and
Drug Administration (FDA), use information from these studies to set
regulatory exposure limits
...

Analytical toxicology identifies the toxicant through analysis of
body fluids (e
...
urine, blood, bile, oral fluid, vitreous humor or cerebrospinal fluid) and tissues (brain cortex, liver, heart, kidney, fat tissues), stomach content, and/or drug paraphernalia
...
Assessment of drugs
effects on behavior and performance, and evaluation of toxic effects,
can be made only after determination of the concentrations of drugs
and of their active metabolites in blood
...
Oral fluid will become the matrix of choice for roadside testing of drugs impairing driving capability
...
The effects of exposure can depend on a
number of factors, including the size of the molecule, the specific tissue type or cellular components affected, whether the substance is eas-

ily dissolved in water or fatty tissues, all of which are important when
trying to determine the way a toxic substance causes harm, and
whether effects seen in animals can be expected in humans
...
Classification of Toxic Agents:
Toxic substances are classified into the following:
A
...
Their use by humans plays an important role in determining their potential for health effects
...
For example,
chromium III can be converted to or from chromium VI, the more
toxic form of the metal
...
Solvents and Vapors
Nearly everyone is exposed to solvents
...
When a solvent evaporates, the vapors may also pose a threat to the exposed population
...
Radiation and Radioactive Materials
Radiation is the release and propagation of energy in space or through
a material medium in the form of waves, the transfer of heat or light
by waves of energy, or the stream of particles from a nuclear reactor
...
Dioxin/Furans

Dioxin, (or TCDD) was originally discovered as a contaminant in the
herbicide Agent Orange
...

E
...
Pesticides
may also be described as any physical, chemical, or biological agent
that will kill an undesirable plant or animal pest
...
Microbial toxins
Bacteria, fungi and algae are the microorganisms typically associated
with microbial toxin production
...

G
...
g
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virosa), produce a family of cyclic octapeptides called amanitins
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Death in 50-90% of the cases
from progressive and irreversible liver, kidney, cardiac damage may
happen 6-8 days after ingestion
...
Plant Toxins
Different portions of a plant may contain different concentrations of
chemicals
...
For example, taxol, used in chemotherapy to kill cancer cells, is produced by a
species of the yew plant
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Perhaps, ingestion of just one milligram of ricin can kill an adult
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Ingestion of a few
grams of roots may result in death occuring from ventricular arrhythmias, which are most likely to occur within the first 24 hours
...
Animal Toxins
These toxins can result from venomous or poisonous animal releases
...
Poisonous animals
are generally regarded as those whose tissues, either in part or in their
whole, are toxic
...
The most toxic frog is very likely
the golden poison frog, Phyllobates terribilis
...
Subcategories of Toxic Substance Classifications
All of these substances may also be further classified according to
their:
Effect on target organs (liver, kidney, hematopoietic system),
Use (pesticide, solvent, food additive),
Source of the agent (animal and plant toxins),
Effects (cancer mutation, liver injury),
Physical state (gas, dust, liquid),
Labeling requirements (explosive, flammable, oxidizer),
Chemistry (aromatic amine, halogenated hydrocarbon), or
Poisoning potential (extremely toxic, very toxic, slightly toxic)
K
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For example, breathing too much pure oxygen, drinking excessive amounts of water, or eating too much salt can
cause poisoning or death
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Toxicological Information Sources
A
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kompendium
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aspx?lang=fr
(ii) Swissmedic: http://www
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ch/?lang=3
(iii) Toxzentrum: http://www
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ch/fre/welcome
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bag
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ch/index
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ilo
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htm
(vi) La liste des toxiques IGS: http://igs
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ch/tox/fr/index
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ch produits chimiques et toxiques:
http://www
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ch/private/00070/00076/00618/00620/index
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prevention
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htm
(ix) Les produits toxiques, la cigarette:
http://www2
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ch/unisansfumee/page5333
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ge
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htm

ISPA: http://www
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ch/index
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usdoj
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html
(xiii) Swissmedic, les produits stupéfiants:
http://www
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ch/fr/industrie/overall
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00105
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00001&theme_id=885
(xi)



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