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8/11/2019 Health and Toxicology
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Health Hazards
Infectious Diseases
Respiratory diseases
pneumonia
tuberculosis
influenza
whooping cough
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Health Hazards
Infectious Diseases - are diseases caused by
the spread of bacteria and pathogens. The
pathogen or any other organism enters thebody and multiplies to survive. Infectious
diseases are contagious and highly
comunicable.
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Health Hazards
Major Infectious Diseases in the Philippines
Degree of risk: high
Food or waterborne diseases:bacterial diarrhea,hepatitis A, and typhoid fever
Vectorborne diseases:dengue fever and malaria
Water contact disease:leptospirosis (2013)
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Health Hazards
Respiratory diseases
Pneumonia
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Health Hazards
Respiratory diseases
Tuberculosis
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Health Hazards
Respiratory diseases
influenza
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Health Hazards
Respiratory diseases
whooping cough
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Classes of Toxic Chemicals
Irritants
Respiratory fibrotic agents
Asphyxiants
Allergens
Neurotoxins
Mutagens
Teratogens
Carcinogens
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Classes of Toxic Chemicals
Irritantsrefers to a condition in the body when itis trying to react to a localized injury of tissues
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Classes of Toxic Chemicals
Respiratory fibrotic agentssubstances that cause inflammationof the airways after they are inhaled
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Classes of Toxic Chemicals
AsphyxiantsA condition in which an extremedecrease in the concentration of oxygen in thebody accompanied by an increase in theconcentration of carbon dioxide leads to loss ofconsciousness or death.
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Classes of Toxic Chemicals
Allergensany substance (antigen), mostoften eaten or inhaled, that is recognizedby the immune system and causes anallergic reaction
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Classes of Toxic Chemicals
Neurotoxinssubstances that are inducingadverse effects in the central nervous system,peripheral nerves or sensory organs
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Classes of Toxic Chemicals
Mutagens substances that causechanges (mutations) in the geneticmaterial of cells
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Classes of Toxic Chemicals
Teratogenssubstance capable ofinterfering with the development of
a fetus, causing birth defects.
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Classes of Toxic Chemicals
Carcinogenssubstances or agentsthat cause cancer
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Movements of Toxins in the Environment
Solubility
1. Water soluble compounds move rapidlythrough the environment and have access
to cells.
2. Fat soluble compounds needs a carrierto move through the environment, butonce inside the body they penetrate thetissues easily . They are stored in bodyfats and persist for many years
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Bioaccumulation
The gradual buildup, over time, of a chemicalin a LIVING ORGANISIM
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Why Does This Happen?
Chemicals are taken up faster than they are
used
Or
Chemicals cant be broken down by the
organism for use
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Pollutants
Chemical pollutants that are bioaccumulated
come from many sources
Pesticides
Industrial Smoke Stacks
Automobile Emissions
Deliberate Discharge of Compounds into Water
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Pesticides Industrial Smoke Stacks
Automobile Emissions Deliberate Discharge ofCompounds into Water
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Biomagnification
The buildup of substances by successive trophic levels
Example: A predator will have higher concentrations of a
chemical compared to its prey
DDT
Soil(10ppm)Earthworms(141ppm)Robins(444ppm)
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1 unit
2 units
6 units
12 units
24 units
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DDT
Dicholoro-diphenyl-trichloroethane
An insecticide used in the 40s, 50s and 60s
entered the environment in run-off from land
Was banned in 1972 after the Bald Eagle
population had a noticeable crash.
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DDT
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Movements of Toxins in the Environment
Persistencethe amount of time a
pesticide remains in the environment,
measured by half-life. Pesticides with
longer half-lives pose a greater threat
to the environment.
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Movements of Toxins in the Environment
Chemical Interactions
- Antagonistic interactionone materialinterfere with the effects or stimulates thebreakdown of other chemicals
- Additive reactioneffects of eachchemical are added to one another
- Synergistic reactionone substanceexacerbates the effect of the other
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Measuring Toxicity
Animal Testing - exposing a population oflaboratory animals to measured doses of specifictoxins
Toxicity Ratings- Moderate toxins takes about 1 g/kg of bodyweight to produce lethal dose
- Very toxic requires 10 % of the same amount
- Extremely toxic requires about 1%
- Supertoxic can be lethal in few micrograms
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Measuring Toxicity
Acute vs. Chronic Doses and Effects
- Acute effect is caused by a single exposure
and results to an immediate health problem
- Chronic effect is a result of a single large or
repeated smaller dose with long last or
permanent effect