Introduction to Environmental Hazards.pdf

An introductions to environmental health hazards

1. Session 2: Environmental
Hazards
Jackim M. Nyamari
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

2. Outline
Definitions -Hazard and Risk
Biological Hazards
Physical Hazards
Chemical Hazards
Cultural/Socio Hazards
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

3. Hazards
A hazard is a source or a situation with the potential for
harm in terms of human injury or ill-health, damage to
property, damage to the environment, or a combination
of these.
Loss of control of the hazards leads to harm.
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

4. Categories of Hazards
Hazards can be broken down into two basic categories:
Acute Hazard–Hazards that pose obvious issues and would
impact instantly.
Chronic Hazard–Hazards that are not immediately
apparent, and can have more of a hidden issue, sometimes
only arising after long periods.
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

5. Risks
Risk is a measure of the likelihood/chanceof harmful effects to
human healthor to ecological systems resulting from exposure
to an environmental stressor.
A stressor is any physical, chemical, or biological entity that can
induce an adverse effect in humans or ecosystem.
Risk = Hazard (H) x Vulnerability (V)
The level of risk reflects:
the likelihood of the unwanted event
the potential consequences of the unwanted event.
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

6. Hazard Vs Risk
‘
Hazard’ and ‘Risk’ are often used interchangeably.
However, these terms have both totally different
meanings and totally different functions.
Hazard: something that could potentially cause harm.
Risk: the degree of likelihood that harm will be caused.
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

7. Types of Hazards
Biological Hazards
Chemical hazards
Physical hazards
Cultural/Social hazards: such as smoking, poor diet,
unsafe sex, drugs, unsafe working conditions, and
poverty.
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

8. Biological
Hazards/Biohazards
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

9. Biological Hazards/Biohazards
Hazards of organic originor conveyed by biological vectors,
including pathogenic microorganisms, toxins and bioactive
substances.
Examples: bacteria, viruses or parasites, as well as venomous
wildlife and insects, poisonous plants, and mosquitoes
carrying disease-causing agents.
They are usually the result of a natural occurrence, but can
also result from deliberate or accidental release.
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

10. Characteristics of Biological Hazards
Agent diversity
Routes of transmission
Pathogenicity and virulence
Hazard identification
Potential for Epidemic Transmission
Sensitivity to Environmental Changes
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

11. Agent diversity
Range from microorganisms
such as bacteria or viruses, to
toxins to insect infestations.
They can be transmitted to
humans from the environment,
from animals, from plants, and
from other humans.
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

12. Routes of transmission.
Airborne transmission,
Ingestion,
Absorption (Skin, eyes, mucous
membranes, wounds),
Animal bites, vectors (e.g.
mosquitos or ticks)
Bodily fluids (e.g. blood, mother-
to child transmission, sexual
transmission).
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

13. Pathogenicity and Virulence
Some biological hazards can
cause severe disease in
extremely low concentrations
and can multiply quickly once
within its host.
For example, 1-10 aerosolized
organisms Ebola virus are
sufficient to cause severe
disease in humans.
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

14. Hazard identification.
Not visible to the naked eye
They therefore require specific
diagnosis techniques, including
polymerase chain reaction (PCR),
to amplify a single copy or a few
copies of a piece of DNA,
microbial cultures, whole genome
sequencing.
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

15. Potential for Epidemic Transmission
Unlike some other hazards, biological
hazards can be present in the
community and usually pose low risk
when the population is largely immune.
The risk may change when crises or
emergencies arise, exacerbating the
conditions favorable for disease
transmission.
Biological hazards, which are not
endemic also pose a risk when they are
introduced to a new host community
with no immunity.
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

16. Sensitivity to Environmental Changes
Biological hazards –particularly zoonoses
and vector-transmitted diseases such as
malaria, dengue, Zikaand Ebola –may
increase in incidence, lethality or change
geographic distribution or seasonal
patterns directly due to climate and
weather sensitivity, environmental or land-
use changes, or mediated through
changes in ecosystems resulting from
human activities, thus changing human
exposures and susceptibility to these
hazards
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

17. Classification of Biological Hazards -WHO
Risk Group 1 (low to no individual or communityrisk): –
Biological agents or organisms that are unlikely to cause
diseases to healthy humans or animals
(Agrobacterium radiobacter, Aspergillus niger, Bacillus
thuringiensis, Escherichia coli strain K12,
Lactobacillusacidophilus)
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

18. Risk Group 2 (moderate individual risk, low community
risk)–Pathogens that are likely to cause diseases to
humans or animals but have minimal potential to be
serious hazards to the workers, community, or the
environment
Examples include:working with human blood,
Streptococcus pyogenes, Giardia spp., Microsporumcanis,
human adenoviruses, Hepatitis virus.
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

19. Risk Group 3 (high individual risk, low community risk)–
Pathogens causing serious diseases to humans or
animals that don’t typically spread from one infected
individual to another, for which preventive and
treatment measures may be present
Examples include:Yersinia pestis, Francisellatularensis,
Coccidioidesimmitis, Prions, Hantavirus, and Influenza
viruses A H1N1 (1918), H2N2 (57-68), and H5N1 (bird flu).
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

20. Risk Group 4 (high individual and community risk) –
Pathogens causing serious diseases to humans or
animals that are directly or indirectly transmissible and
for which preventive and treatment measures may not
be available
Common examples of RG4 pathogens include Ebola and
Hendra virus.
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

21. Routes of Exposure
Biological hazardscan enter the body by different
routes.
When determining appropriate protective measures, a
clear understanding of how biological hazards enter the
body is an important first step.
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

22. Routes of Exposure Cont.…
Inhalation; i.e., breathing
Absorption; i.e., direct contact
through breaks in the skin, even
chapped skin, or through mucous
membranes/contact with eyes,
nose, mouth
Ingestion
Injection; i.e., through a puncture
Animal bite –snake, scorpion….
The mostcommon routes are
inhalationand contact.
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

23. Physical Hazards
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

24. Physical Hazards
“A factor within the environment that can harm the
body without necessarily touching it.”
Factors, or circumstances that can cause tissue damage
by transfer of energy from the agent to the person.
Conditionsor situations that can cause the body
physical harm or intense stress. -can be both natural
and human made elements.
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

25. Types of Physical Hazards
Heat and Cold
Light/illumination
Vibration -Vibration
Ionizing Radiation
Noise
Construction Work & Demolition
Natural Disasters –Floods, earth quakes, landslides tsunamis
Accidents
Fires/Electrical
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

26. Health & Health -WHO
•Global temperatures
and the frequency
and intensity of
heatwaves will rise in
the 21st century as a
result of climate
change.
https://www.who.int/news-room/fact-sheets/detail/climate-
change-heat-and-health
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

27. Light and Health
An increased amount of
light at nightlowers
melatonin production,
which results in sleep
deprivation, fatigue,
headaches, stress,
anxiety, and other health
problems.
https://www.sciencedirect.com/science/article/abs/
pii/S1001074222003291
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

28. Vibration and Health
Vibration from poorly designed or
poorly maintained vehicles, or
machinery may various health
effects such as:
Lower back pain (damage to
vertebrae and discs, ligaments
loosened from shaking)
Motion sickness.
Bone damage.
Damage to blood vessels, body
tissues, and nervous system to the
fingers, hands, and arms due to
segmental vibration,
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

29. Radiation and Health
Ionizing radiation can fall into two
categories:naturalandmanmade
Ionizing radiation that comes from
natural sources is typically at low
levels.
Medical diagnostic exams are the
main manmade source of ionizing
radiation exposure
Health Effects: Skin or tissue
damage, cancer, hair loss, acute
radiation syndrome, cataracts…..
Radiation
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

30. Noise and Health
Noise Induced Hearing Loss
(NIHL).
High blood pressure,
Heart disease,
Sleep disturbances, and stress.
Speech interference,
Lost productivity
These health problems can
affect all age groups,
especially children
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

31. Natural Disasters
Injuries
Loss of lives
Hygienic and sanitation Impacts
and the Spread of Disease.
Food Shortages.
Mental Health Problems.
Damage to Healthcare
Infrastructure.
Damage to property, transport
networks …..
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

32. Accidents –traffic, industrial, buildings
Injuries and disability
Loss of Life
Disease transmission
Environmental pollution
Economic losses
Mental disorders
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

33. Fire
Injury and disability
Loss of life
Destruction of property
Environmental pollution
and greenhouse gases
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

34. Other Physical Hazards
Electrical Falling Objects
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

35. Slippery Floor Fire/Flammable
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

36. Cold Temperature
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

37. Chemical Hazards
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

38. Chemical Hazards
A chemical hazard isa chemical substance that could
potentially cause harm to the human body or even
cause loss of life.
A materialthat has chemical characteristic of potential
for causing harm.
Human injury,
Damage to property,
Damage to environment or
Some combination of these is known as hazardous
chemical
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

39. The chemicals hazards can be in the form of gases,
solids or liquids. Exposure to chemicals could cause
acute health effects.
A person is exposed to chemicals through various ways:
Inhalation of the vapors, gases or dusts;
Through skin contact with solvents, acids and alkalis;
and through ingestion of unknown chemicals with food
and water.
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

40. Classification of Chemical Hazards
Carcinogen-Cancer (uncontrolled cell growth) causing agent,
either by itself or in conjunction with another substance
Teratogen-A substance which can cause physical defects in a
developing embryo.
Mutagen-A material that induces genetic changes (mutations)
in the DNA.
Neurotoxin-A substance that can cause an adverse effect on
the chemistry, structure or function of the nervous system.
Endocrine disruptor-
A chemical that may interfere with the
body’s endocrine (hormonal) system and produce adverse
developmental, reproductive, neurological, and immune
effects in both humans and wildlife.
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

41. Physical Characteristics of Hazardous
Chemical
Ignitability
Corrosivity,
Reactivity
Toxicity
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

42. Jackim M. Nyamari, Dept of Community Health -Aga Khan University

43. Factors determining the harm caused by
exposure to a chemical include:
The amount of exposure (dose).
The frequency of exposure.
The person who is exposed.
The effectiveness of the body’s detoxification systems.
One’s genetic makeup.
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

44. In General…..
The effect of an
environmental hazardon
individual health is
influenced by several
factors:
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

45. Hazardous to
Health
Serious Health
Hazard
Gas under Pressure
(Gas Cylinder
Explosive
Flammable
Oxidising
Corrosive
Toxic
Hazardous to
the Environment
Communicating about Hazards Using Symbols
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

46. Principles of Hazard Management Cont..
Establish the context and identify the hazard
Hazard/risk analysis and evaluation
Communicate and consult
Control/Treat the hazard/risk
Monitoring and reviewing
Record keeping -
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

47. Principles of Hazard Management
Jackim M. Nyamari, Dept of Community Health -Aga Khan University

48. Thank You
Jackim M. Nyamari, Dept of Community Health -Aga Khan University