Air Wter Soil

8/13/2019 Air Wter Soil

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Objectives

Differentiate hazards and risk Give examples of Environmental Hazards Give examples of Environmental Hazards

according to area Explain several pathway of environmental

hazards Explain several routes of exposure of

environmental hazards


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Hazard vs Risk

A hazardis defined as 'a factor or exposure thatmay adversely affect health" (Last,1995);

it is basically a source of danger .Hazard is a qualitative term expressingthe potential of an environmental agent toharm the health of certain individuals ifthe exposure level is high enough and/ orif other conditions apply.


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A risk is defined as "the probability that an event will

occur, e.g., that an individual will become ill or die within a stated period of time or beforea given age;

the probability of a (generally) unfavorableoutcome " (Last, 1995).

It is the quantitative probability that a healtheffect will occur after an individual has beenexposed to a specified amount of a hazard.

Hazard vs Risk


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Types of Environmental HealthHazards

Sources of Environmental health hazards :natural and anthropogenic (human caused).Biological hazards : bacteria, viruses, parasites,

and other pathogenic organismsChemical hazards : toxic metals, air pollutants,solvents, and pesticidesPhysical hazards : radiation, temperature, andnoiseMechanical hazards : motor vehicle, sports,home, agriculture, and workplace injury hazardsPsychosocial hazards : stress, lifestyledisruption, workplace discrimination, effects of

social change, marginalization, andunemployment


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Traditional Versus ModernHealth Hazards

Traditional Hazards Modern Hazards

Disease VectorInfectious agentsInadequate housing & shelterPoor quality drinking water &sanitationIndoor air pollution fromcookingDietary deficienciesHazards of Child BirthWildlife & domestic animals

Injury hazards in agriculture

Tobacco smokingTransport hazardsPollution from sewage &industryOutdoors air pollution fromindustries & motorcars

Overuse or misuse ofchemicalsIndustrial machineryUnbalanced diet


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Common Classes of EnvironmentalHealth Hazards

Chemical Physical Biological Mechanical PsychosocialLead Noise Bacteria Vibration Violence

CarbonMonoxide

IonizingRadiation

Parasites RepetitiveMotion

Stress

Benzene Electromagneticfields

Viruses Lifting High demand/Low controloccupation

VinylChloride

Temperaturesextremes

Vectors


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Route of Exposure


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Biological Hazards


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Types of Biological Hazards

all of the forms of life (as well as the nonlivingproducts they produce) that can cause adversehealth effects.

These hazards are plants, insects, rodents, andother animals, fungi, bacterial, viruses, and awide variety of toxins and allergens.

A disease that can spread from one person toanother it is called an infectious orcommunicable disease


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Spread of Biological Hazards

Water polluted by human excreta : cholera, typhoidfever, dysentery, other diarrheal diseases, hepatitis,and schistosomiasis.Inadequate sanitation, the dumping of untreated

sewage into surface water, and poor hygienicpracticesOvercrowding and poorly ventilated housingcontribute to the airborne transmission oftuberculosis, measles, influenza, pneumonia,pertussis, and cerebrospinal meningitis.Unhygienic animal husbandry helps to transmitzoonoses (animal diseases that can also afflicthumans)


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Spread of Biological Hazards

Many parasites cause tropical diseases, which occuralmost exclusively in tropical areas. It is dependent onan insect vector, which can only survive in certainclimates. Examples : malaria, schistosomiasis, filariasis,and dracunculiasis (Guinea worm disease).Environmental changes and disturbances to the balanceof natural habitats may have profound effects on thespread of infectious diseases. New outbreaks such asthe one reported in Congo in 1995 caused by the Ebolavirus, have emerged lately when people encounteredthem by entering an unfamiliar or remote habitat.


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Routes of Exposure

The main environmental exposure routes forbiological hazards are air, water, and food.Some parasites enter the body by penetrating

the skin (e.g., hookworm, schistosomiasis) andothers enter a human body by insect bites (e.g.,malaria).Bacteria and parasites may also spread fromcontaminated soil to the skin or via dust to theair, and eventually infect a person.


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Routes of ExposureVia air : respiratory diseases, due to small droplets created while coughing or

sneezing. Example : common cold, tuberculosis bacteria, and

the Legionnaire's disease bacterium.Via water: When the drinking water supply for a community is

contaminated with feces from one sick person, a largenumber of people drinking the water can fall ill and inturn spread the disease via their feces.

Example : Cholera


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Routes of Exposure

ingestion of foodthe problem of helminths (worms) from aninfected person that defecates on soil.


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Health Effects

Infections : Diarrhea, cholera, typhoid, paratyphoid,

salmonella, and shigella. Respiratory infections HIV/ AIDS tuberculosis


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Spread of Chemical Hazardsnatural geological processesmining and dredging,as wastes from many industrial, agricultural,commercial, domestic, and manufacturingsourcesproduction, storage, and transportation ofproducts such as household products.

Air, soil, fresh waters, and oceansContamination of foodNatural toxins (aflatoxins, ochratoxins,pyrrolizidne alkaloids)


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Route of Exposure

Inhalation (mostly occupational)Oral ingestion (mostly non occupational)

Absorption through the skin (mostly

occupational) Absorption through the eyesPlacental transfer from a pregnant womanto the fetusInoculation and direct penetration to targetorgansfrom mother to child through breastfeeding


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Distribution, Metabolism, andElimination


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Toxicity Testing in ExperimentalAnimals

Tests to determine the toxicological profileof a chemical assess acute, sub chronic,

and long term toxicity or focus on specificareas of toxicityThe toxicological profile and the doseresponse relationship first stages in riskassessment.

Acute Toxicity Studies Acute animal studies to predict human effects of short term,

high level exposures


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Physical Hazards


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Types of Physical HazardsNoise and Vibration Risk of incurring hearing loss begins with

prolonged exposure to sound of approximately 7 5dB (A) (WHO). Many countries use 85 dB as thenoise safety limit in workplaces.

Vibration is transmitted by air to the ear, anddirectly to other parts of the human body.

The use of many tools or hand equipment canresult in adverse health effects as a result of armand hand vibration.

Vibrations can also be transmitted to the entirebody when driving vehicles like bulldozers,excavators, trucks, and cars on rough lands orbumpy roads. These vibrations may damage themusculoskeletal system.


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Types of Physical HazardsIonizing Radiation

Ionizing radiation emerges when an electron isremoved from a neutral atom and a pair of ions

are produced a negatively charged electron and apositively charged atom. It is the ionization of atoms in the human body that

causes harmful biological effect. The ions arehighly reactive and damage critical cell structures,including proteins and DNA.

Ionizing radiation is defined as electromagneticradiation with sufficient energy to displace anelectron from an atom.


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Environmental Hazards according to Area(Local to global area)


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Living Problems

Environmental tobacco smoke Noise exposure

Urban Crowding Residential lead-based paint


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Work Hazards

Toxic substances Machine-operating hazards

Repetitive motion injuries Carcinogenic work exposure


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Atmospheric Quality

Greenhouse gases and global warming Depletion of the ozone layer Aerial spraying of herbicides and pesticides Acid rain


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Water Quality

Contamination by human waste Oil and chemical spills in waterways Pesticide/ herbicide contamination of

groundwater and runoff to local waterways Aquifer contamination by industrial

pollutants Toxic contamination of fish and seafood


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Housing

Rodent and insect infestations Particulates from woodburning stoves

Houses and buildings with poor ventilationsystems sick building syndrome Off gases from carpets and plastics used

in home construction


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Radiation

Nuclear facility emissions Radioactive nuclear waste Radon gas Nuclear testing Excessive exposure to X rays Ultraviolet radiation (UVB) due to global

depletion of stratospheric ozone


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Violence

Proliferation of handguns Pervasive images of violence in the media Violent acts against women and children Excessive incidents of violence in

workplaces, schools, and communitysettings


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Effects of air pollution

Human health Ecosystems Property Aesthetics Economy Weather


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Vulnerable PopulationsIndividuals vary widely in their susceptibility to adversehealth effects following exposure to toxic substances.

Personal characteristics : Age Genetic

compositionNutritionalstatus

Sex Preexistingdiseases state

Physiologicstatus

Weight Behavior &lifestyle factors

Concomitant/last exposure


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Vulnerable PopulationsThe unique vulnerabilities of individuals at thetwo extremes of the life cycle, that is, youngchildren and the aged. Why ?

Young children have immaturity infunctioning of major physiologic processesThe aged have normal decline in that.


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Assignment

NOTICE THIS DATA !

Deaths in the Population Supplied by the Southwark &Vauxhall Water Company & the Lambeth Water Company,London 1853

Name of WaterCompany

No. of Homes Deaths fromCholera

Deaths in each10.000 Homes

Vauxhall &Southwark Co.

40.046 1263 315

Lambeth Co. 26.107 99 37

Rest of London 256.423 1422 59


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AssignmentSouthwark and Vauxhall Company took their water fromdownstream of Thames river, while Lambeth Company took itswater from upstream of Thames river.Questions :

1.Who have risk to get cholera ?2.What is the type of environmental hazard in this case ?3.What is the area level of environmental hazard this case ?4.How can this case probably happen ? What is the pathway ?

5.What is the route of exposure of this hazards ?6.Write one paragraph that addresses the events that impacthuman health !

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