Environmental Hazards and Risks

the possibility of suffering harm from a hazard that can cause injury, disease, or environmental damage

injury, disease, or death to humans damage to personal or public

property deterioration or destruction of

environmental components

A. Lack of familiarity with technology

B. Extent to which the risk is voluntary

C. Public impression of hazards D. Overselling of safety E. Morality F. Control G. Fairness

Cultural Chemical Physical Biological

Natural disasters Fires Ionizing radiation

Electromagnetic radiation (UV rays, X-rays, gamma radiation, etc) which has enough energy to knock electrons from molecules and cause damage to cells.

Can damage reproductive or somatic cells

Transmissible diseases like yellow fever, flu, dengue fever, tuberculosis, malaria, etc. Pathogen - infectious agent Vector - helps to spread the pathogen

(mosquitoes of greatest concern) Malaria - huge problem in subtropical and tropical

areas. The pathogen is a protozoan (Plasmodium) and the vector is the Anopheles mosquito.

Drug resistant bacteria are becoming more prevalent due to overuse and misuse of antibacterial products

Non-transmissible diseases Cardiovascular disease, cancer, diabetes,

emphysema, etc.

CulturalPoverty - according to WHO this is the biggest killerSmokingUnsafe sexDiet - people in developed nations are more likely

to die from cardiovascular related diseases

Mutagens Teratogens Carcinogens

Consist of hundreds of highly persistent chemicals.

Some of the most toxic substances known. The worst is TCDD.

No safe level of exposure. These are biproducts of industrial

processes that use chlorine like paper bleaching, the production of PVC plastic, and pesticides.

Primary toxic component of Agent Orange and found at the site of Love Canal.

Carcinogenic Causes reproductive problems:

increases likelihood of miscarriage, decreases fertility, and sperm counts

Also linked to diabetes, skin disorders, immune deficiencies, and learning disabilities

Fat-soluble; bioaccumulates in living organisms

93% of exposure is through meat and dairy products

It is hydrophobic and lipophilic (which means when it gets into water, it will rapidly accumulate in fish bodies)

In women, dioxins can cross the placenta and it is present in breast milk

Viktor Yushchenko Does freezing water release dioxins?

How about microwaving plastics?Major source of release is incineration

No longer produced in U.S. Highly prized for flame resistance and

used in many electrical products b/c they didn’t burn or react with other chemicals

Found in such varied items as heating coils, carbonless carbon paper, power saws, cereal boxes,varnishes, and bread wrappers.

Persistent Bioaccumulate in fat; biomagnify

through food chain Highly toxic: can be ingested,

inhaled, or absorbed through the skin Health effects: chloracne, damage to

liver, damage to nervous system, damage to reproductive system, and may affect immune system

Can be exposed by contact with old appliances, old flourescent lighting fixtures, food or water intake, or in some jobs

Often associated with exposure to pesticides:These suppress the body’s natural

defensive mechanisms and make the body more vulnerable to disease.

Called neurotoxins and affect the brain, spinal cord and peripheral nerves

Include DDT, PCBs, dioxins, organophosphate pesticides, formaldehyde, compounds containing heavy metals (As, Hg, Pb, and Cd), and industrial solvents like trichloroethylene (TCE), toluene, and xylene.

Affect the body’s hormones. Each hormone has a specific molecular

shape which allows it to bind to only specific cell receptors, but some chemicals may act as hormone mimics or blockers and fool the cells by either binding to them or blocking them from the proper hormone

Ranch minks Lake Apopka alligators Rats exposed to PCBs p-nonylphenol Florida panthers

Toxicity - the measure of how harmful a substance is.

Dose - amount of potentially hazardous substance that has entered the individual. The amount of harm will depend on the size of the dose over time. a. Acute exposure - single dose. b. Chronic exposure - doses over most of a lifetime. c. Subchronic exposure - repeated doses for some

fraction of a lifetime. “The dose makes the poison.”

Response - type and amount of damage as a result of exposure.a. Acute effect - immediate or rapid

harmful reaction.b. Chronic effect - permanent or long-

lasting consequence from exposure.

c. Multiple chemical sensitivity - an individual becomes sensitive

to many chemicals at the same time.

Case reports Laboratory investigations Epidemiology (involves the study of

various human populations which have had exposure to the chemical)

Lethal Dose 50% is the amount of one dose of a chemical that can kill 50% of the animals in a test population in a 14 day period.

A poison is a chemical with an LD50 of 50 milligrams or less per 1 kilogram of body weight.

-is developed with acute toxicity tests. These are done as controlled experiments. Some of these curves have threshold levels, while others do not. -a threshold level implies, that there must be some minimal level of exposure before any effects are seen.

Water soluble Fat soluble

an increase in the concentration of a chemical in specific organs or tissues at levels higher than normally expected.

The residence time of a chemical is given by its biological half-life (the time needed for the quantity of the chemical in the body to be reduced by half).

a magnification of the levels of some toxins in the environment as the pass through food chains/webs.

i. Examples: PCB’s. DDT, radioactive isotopes

ii. Passed to offspring through gestation and nursing