Download Toxicology

Toxicology
The study of poisons and their effects,
on living systems
Love Canal Cleanup Finished,
Mutants Return to Homes
We knew there were too many miscarriages, too many birth defects, too
many central nervous system problems, too many urinary tract disorders,
and too much asthma and other respiratory problems among us."
Health: A state of complete physical,
mental, and social well-being
 Disease: A deleterious change in the body’s
condition in response to an environmental
factor that could be nutritional, chemical,
biological, or psychological
 Morbidity: Illness

Types of Environmental Health
Hazards
Infectious Diseases
 Toxic Chemicals
 Natural or Synthetic Toxins
 Physical Agents, Trauma and Stress
 Diet

Pathogens are infectious organisms
Bacterial
 Protozoans (guardia)
 Fungal
 Invertebrate Animals
 Viruses are non living

Bacterial Infections:
Trachoma is an inflammation of eye
Sexual Transmitted Diseases (gonorrhea and
syphilis)
Respiratory Diseases: Pneumonia,
tuberculosis, influenza, and pertussis
Bacteria have developed resistance to
antibiotics
Improved drugs and sanitation can eliminate
some diseases
Trachoma,the most commonly
contracted STD, caused by
Chlamydia trachomatis
Emergent diseases

Those not previously known or that have
been absent for more than 20 year
*many are viruses
Viral Infection
SARS and Bird flu
 HANTA, Ebola
 West Nile virus causes encephalitis
 HIV and AIDS

Fungal
Sudden oak death
 Fungal spores *black mold

Protozoans
Malaria: Infection of red blood cells by the
protozoan Plasmodium spread by the
Anopheles mosquito
 Giardia: dysentery
 Amoeba:dysentery

Invertebrate Animals (Parasitic)
Flatworms (flukes) and tapeworms
 Nematodes (roundworms)

–
–
–
such as hookworms, guinea worms
Filariasis worms block lymphatic vessels
causes elephantiasis
Caused by Nematodes (Roundworms)
Elephantiasis
Filariasis
Guinea worms
prions

Proteins resistant to temperature. They
cause Chronic Wasting in Wild Animals and
Mad Cow Disease also known as
Creutzfelt-Jacop disease
Toxic Chemicals
Hazardous: Dangerous
 Toxic: Poisonous
 Irritants: Corrosives (acid), caustics (base),
and other substances that damage biological
tissues
 Respiratory Fibrotic Agents: Irritants that
damage the lungs


Asphyxiants: Chemicals that exclude
oxygen or actively interfere with oxygen
uptake and distribution (i.e. MIC)
Allergens:
Substances that activate the immune system.
Some act as Antigens which are recognized as foreign by
white blood cells. Antigens cause the immune system to
produce Antibodies.
Mutagen: with change the base sequence
in DNA, may be harmless or harmful.




Cancer: Invasive, out-of-control cell growth that
results in malignant tumors
Carcinogens: Substances that cause cancer
Promoter: Bases sequences in DNA that regulate
expression of that gene
Terratogens: discussed further
Mutagens: Agents that
damage or alter DNA

Teratogens: Factors that cause abnormalities
during embryonic growth and development
(example: thalidomide)
–
–
Fetal Alcohol Syndrome: Symptoms including
craniofacial abnormalities, developmental delays,
behavioral problems, and mental defects.
Thalidamine: used to prevent morning sickness
and in treatment of leprosy.
Thalidomide for morning sickness
Carcinogens
aflatoxin
acrylamide
Francis Oldem Kelsey
Prevent FDA from approving
Prevented 1000 birth defects in USA
Awarded President’s Award for Distinguished
Federal Civilian Service
Endocrine Disrupters
 Neurotoxins: Attack nerve cells

–
–
–
Heavy metals (mercury, lead)
Chloronated hydrocarbons (DDT, dioxin)
disrupt nerve cell membranes
Organophosphates (pesticides
organophosphates
mercury
How Do Environmental Toxins
Enter Our Bodies?
introduced into our lives everyday
 depend on where we live
 They are in the air you breath, the food you
eat, water, buildings, pesticides, and
consumer products.
 They are the byproducts of industry

Basic Concepts


Def: science that studies poisons or toxics
Pathways from environment -> us
–
–
–
oral ingestion
inhalation
percutaneous absorption (skin)

17.8% of California’s lakes are under fish
consumption advisories due to mercury,
dioxins and other Persistent
Bioaccumulative Toxins!!!

The average household uses and stores
more than 60 hazardous materials, including
household cleaners, automotive products,
paints, solvents and pesticides
Household sources of Toxic
Chemicals
Off the shelf pesticides, herbicides,
fungicides and insecticides
 Paints and paint cleaning supplies
 Household cleaning solutions, laundry
detergents with phosphates
 Bleached paper products


Over 150 chemicals found in the average
home have been linked to allergies, birth
defects, cancer and psychological
abnormalities
Consumer Product Safety Commission
www.earthwellness.com
Some of the biggies
Dioxin is an unintentional bi-product of
industrial processes using chlorine. It
includes more than 200 chemicals.
 PVC, Polyvinyl Chloride, is the most
widely used plastic

Physical Agents, Trauma, and
Stress
Trauma: Injury caused by accidents or
violence
 Stress: Physical, chemical, or emotional
factors that place a strain on an organism for
which there is inadequate adaptation

Movement, Distribution and Fate of
the Toxin
Solubility
water vs fat soluble
 Bioaccumulation and Biomagnification
 Persistence
 Chemical Interaction

Bioaccumulation and
Biomagnification
Bioaccumulation: The ability of cells to
absorb and store of a select molecules
When is this beneficial vs detrimental?
 Biomagnification: the toxin level
accumulates in those organisms higher up in
the food chain. i.e. DDT

Chemical Interactions

Antagonistic: One chemical counteracts the
effects of another
–

Vitamins A, C, and E reduce response of some
carcinogens
Additive and Synergistic: : two chemical
that occur together exacerbates the effects
of another
How Do We Measure Toxicity
Animal testing
 Toxicity ratings
 Acute verses chronic doses and effects
 Detection limits

Animal Testing

LD50: The dose of a toxic chemical to
which 50% of the test population is
sensitive 9.11, 9.12
Acute vs Chronic Doses and
Effects
Acute Effects: Effects causes by a single
exposure to the toxin resulting in an
immediate health crisis
 Chronic Effects: Long lasting or
permanent effects
 Exposures: If long lasting can be chronic
9.13

Fig 8.17
Risk
Risk: The probability of harm times the
probability of exposure
Assessment & Management
High Risk: Habitat destruction, loss of
biodiversity
Medium Risk: Toxins
Low Risk Oil Spills, Radionuclides

What happened in Bhopal, India?
Methylisocyanate
An irritant, causes burning and swelling of
soft tissue
 The lack of oxygen lead to death
 Blindness to the survivors

What happened in Chernobyle
How Can We Reduce Our Risk of
Exposure to Environmental
Toxins?
Increase your awareness
pass that knowledge on to friends and family
Limit your exposure to toxic chemicals by knowing what
is in the products you buy for yourself and family.
Use minimal amounts of organic pesticides and fertilizers
and encourage your neighbors to do the same Express
your views to and make demands on your local
representatives, school board, federal agencies

Change your lifestyle by minimizing your use and
exposure to toxic substances!
Encourage those around you to change theirs



Buy organic fruits and vegetables, meats, and dairy
products as much as possible.
Limit your use of products (toilet paper, tampons,
and other paper products) which have been through
a chlorine process to whiten the product.
Limit your exposure to plastic products.
Use minimal amounts of organic pesticides and
fertilizers and encourage your neighbors to do the
same.