Disability-Adjusted Life Year (DALY) combines premature deaths and loss of

healthy life resulting from illness or disability. (1.4 billion a year)

90% of DALY occur in developing countries WHO reports 50% due to communicable disease

For most of human history, the greatest health threats have been

pathogenic organisms, accidents, and violence.

EMERGENT DISEASE – Never known before or has been absent for 20 years or more

Spreads Rapidly – modern travel means

Example – FOOT & MOUTH DISEASE

Infectious diseases are still responsible for about 24% of all disease-related deaths.

Majority of these deaths in poorer countries with poor nutrition, sanitation, and vaccination programs.

AIDS now largest single cause of communicable death in the world.

Risk Assessment & ManagementRisk = probability of exposure x probability of harm

Risk Assessment1) ID potential hazard

2) Probability of occurrence

3) Determine how much damage

(social; env; economic)

Controversy over assessments – WHY?

Disputes over variables such as - # exposed, level of exposure, and impact due to age/health/sex of organism

1) How Serious?

2) Can it be reduced?

3) How can it be reduced?

4) $$ to clean it up?

Risk Management

After Assessment

4 Main Types of Hazards smoking (case study), unsafe working

conditions, diet, drinking, driving, poverty!

Cultural

Chemical

synthetic chemicals from water & air pollution – human body contains over 500 syn.chemicals not known prior to 1920

ionizing radiation, earthquakes, volcanoes, hurricane, tornadoes

pathogens (bacteria, viruses, parasites), pollen and other allergens; animals (bees, snakes)

Physical

Biological

Biological HazardsEpidemiology – the study of factors affecting the health and illness Epidemiology – the study of factors affecting the health and illness

of a populationof a population

Dose Response Curve

Non-Transmittable Disease – – not caused by living organisms and does not spread from person to personCardiovascular disease,

obesity, diabetes, most cancers, bronchitis

Transmissible Disease – – caused by living organisms (bacteria, protozoa, and parasites) and virusesPathogens (disease causing organisms) spread through water, air, food, insects, & body fluids - VECTORS

TRANSMISSIBLE TRANSMISSIBLE DISEASEDISEASEAccording to the WHO & UNICEF 2 million children in developing According to the WHO & UNICEF 2 million children in developing

countries die each year due to preventable infectious disease.countries die each year due to preventable infectious disease.

80% of the infectious disease is spread through waterborne infections (diarrhea, hepatitis, typhoid fever, and cholera)

Seven Deadliest Infectious Disease:

1)1) Tuberculosis (TB) bacterial diseaseTuberculosis (TB) bacterial disease

2)2) Malaria – protozoaMalaria – protozoa

3)3) Respiratory Disease – mostly pneumonia Respiratory Disease – mostly pneumonia (bacteria and viruses)(bacteria and viruses)

4)4) Diarrheal Disease – bacterial & viruses Diarrheal Disease – bacterial & viruses (unclean water)(unclean water)

5)5) Measles – viralMeasles – viral

6)6) Hepatitis – viralHepatitis – viral

7)7) HIV/AIDS – Viral HIV/AIDS – Viral

CHEMICAL HazardsImmune Systems – protects the body

against disease Disruptors – viruses, bacteria, parasites, Disruptors – viruses, bacteria, parasites, malnutrition, ionizing radiation, synthetic malnutrition, ionizing radiation, synthetic chemicalschemicals

Nervous System – brain; spinal cord; peripheral nerves Neurotoxins – synthetic chemicals = chlorinated Neurotoxins – synthetic chemicals = chlorinated hydrocarbons (DDT, PCBs, dioxins); organophosphates hydrocarbons (DDT, PCBs, dioxins); organophosphates (malathion); formaldehyde; heavy metals (mercury, (malathion); formaldehyde; heavy metals (mercury, lead, cadmium)lead, cadmium)

Endocrine – glands and hormones that regulate body functions

Disruptors – (HAA’s – hormonally active agents) = can Disruptors – (HAA’s – hormonally active agents) = can mimic or block natural hormone responses – many mimic or block natural hormone responses – many synthetic chemicals such as atrazine, DDT, PCB’ssynthetic chemicals such as atrazine, DDT, PCB’s

Endocrine disruptors have major impacts on reproductive systems

1) Size of the dose over time

2) How often exposure occurs

3) Who is exposed

4) How well the body’s detox system works

5) Genetic make-up of organism

Factors affecting Toxicity

Toxicity – measure of how harmful a substance is.

Dosage – the amount inhaled, absorbed, or

ingested

EXAMPLES: DDT (synthetic organic pesticide), PCB’s (oils used in

electrical equipment); Mercury (heavy metal)

Many chemicals are used because of their long Many chemicals are used because of their long persistence or resistance to breakdown: plastics, persistence or resistance to breakdown: plastics,

CFC’s, Chlorinated Hydrocarbons (DDT)CFC’s, Chlorinated Hydrocarbons (DDT)

This also means they have a lasting impact on the environment

Bioaccumulation – chemicals are stored in

specific organs or tissues at levels higher

than normal

Biomagnification – levels of toxins in the

environment are magnified as they pass

through food chains

DANGEROUS CHEMICALS

•Dangerous chemicals are divided into two broad categories:

Hazardous - Dangerous

-Flammable, explosive, irritant, acid, caustic.

Toxic -Harmful

-Can be general or very specific. Often harmful even in dilute concentrations.

Poison – has an LD50 of 50 mg or LESS

•Allergens - Substances that activate the immune system.

Antigens - Allergens that are recognized as foreign by white blood cells and stimulate the production of specific antibodies.

•Neurotoxins - Special class of metabolic poisons that specifically attack nerve cells.

-Heavy Metals kill nerve cells.

-Chlorinated Hydrocarbons disrupt nerve cell membranes. (DDT, PCBs, dioxins)

-Organophosphates inhibit signal transmission between nerve cells. (malathion)

Insecticides

•Mutagens - Agents that damage or alter genetic material.

Radiation (x-ray equipment)

•Teratogens - Specifically cause abnormalities during embryonic growth and development.

Alcohol - Fetal Alcohol Syndrome

PCB’s, steroids, lead & mercury

•Carcinogens - Substances that cause cancer.

Cigarette smoke, dioxins, radon gas, asbestos

100 million Antibiotic doses prescribed each year in the US – many unnecessary

ANTIBIOTICS More than ½ of the antibiotics manufactured in the US are fed to farm animals to stimulate weight gain

RESISTANCEMany protozoans and insects are now immune to most antibiotics & pesticides (rapid evolution)

Humans overuse and therefore add pressure to adapt and change.

•Solubility - One of most important characteristics in determining the movement of a toxin.

•Chemicals are divided into two major groups:

-Those that dissolve more readily in water.

-Those that dissolve more readily in oil.

Water soluble compounds move rapidly through the environment, and have ready access to most human cells.

RATE OF MOVEMENT & DISTRIBUTION

•Animal Testing

Most commonly used and widely accepted toxicity test is to expose a population of laboratory animals to measured doses of specific toxins.

-Sensitivity differences pose a problem.

Dose Response Curves

LD50 - Dose at which 50% of the test population is sensitive.

LD50 = median lethal dose: the amount of a chemical received in one dose that kills exactly 50% of the organisms in a population (typically in a 2 week period of time)

Animal Testing

Takes 2-5 years – costs between 200,000 – 2 mil

Threshold = dosage amount at which no negative effects are seen

Infectious Agents

Environmentally transmitted infectious disease

contaminated food, water, soil, air

Giardia - protist (water) Salmonella - bacteria (food)

Toxic Heavy Metals

heavy metals that pose hazards to health conditions

by-products of mining, refinging

mercury, lead, nickel often neuro-toxins

Organic Comp.carbon baseded -synthetic organic material

pest control, fertilizers, food additives

ACS reports over 4 million known substances

Radiation

decay of radioactive isotopes measured in sieverts (unit)

nuclear energy, naturally occuring decay (radon)

radon exposure, nuclear accidents, x-rays, atomic fallout

Thermal unwanted heat increase from norm.

natural events,power plants & steam generators

Temp range for life Temp affects DO levels in aquatic environments

Particulatessmall particles of dust released into atmosphere

natural - volcanos, fires un-natural - burning (coal) farming practices

Respiratory problems Normally synergistic effects

Asbestossmall, elongated mineral fragments

industrial use - building materials, insulation in houses, pipes, cars, flooring

repiratory disease, cancer causing (tumors)

What Where example