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Module II

• Hazards and Health Effects

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Objectives

• After completing this module the course
  participants should
• Understand the routes of entry for lead into the
  body.
• Know the organs and systems affected by lead.
• Understand the acute and chronic effects of lead
  to these organs and systems.
• Know the types of medical tests used for
  detecting lead exposure

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Routes of Entry
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Routes of Entry

• Lead gets into the body by the following routes
  of entry
• Inhalation (breathing)
• Ingestion (swallowing)
• Skin absorption

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Inhalation

• Inhalation is the primary route of entry for
  lead.
• Occurs when lead dust or fume is released into
  the air and inhaled.
• sand blasting or grinding operations
• welding on steel coated with lead-based paint
• Fine lead particles may be present in high levels
  yet not be visible to the naked eye.

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Inhalation (continued)

• Airborne particales is easily inhaled
• The larger lead particles become trapped in the
  mucous in the nose and throat.
• The lead containing mucous is either
• Coughed up and spit out
• Swallowed entering the digestive system.
• The smaller lead particles penetrate deep into
  the lung reach the alveoli.
• Where oxygen passes through the air sacs into the
  blood
• Carbon dioxide comes out of the lung, and is
  exhaled.

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Inhalation (continued)

• There are millions of these tiny air sacs
• Within the alveoli, the lead is absorbed into the
  blood.
• Approximately 40 to 50 percent of the lead that
  is inhaled is absorbed into the body

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Ingestion

• Ingestion occurs when lead enters the mouth by
  eating food, drinking beverages, smoking
  cigarettes, or applying cosmetics
• Once inside the mouth, the lead is swallowed.
• The lead then enters the digestive system where
  some of the lead is absorbed directly into the
  bloodstream.
• Approximately 5 to 10 percent of the lead is
  absorbed
• Remainder is passed out of the body with the
  feces

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Ingestion (continued)

• Lead-based paint was banned from residential
  because of lead poisoning in children.
• Young children tend to place objects into their
  mouth.
• Some lead compounds have a sweet taste.
• Resulting children eating lead-based paint flakes
  and dust.
• A growing child requires additional nutrients
  that adults.
• In the absence of sufficient nutrients, a child
  will absorb higher percentages of lead.

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Skin absorption

• Certain lead compounds can be absorbed through
  the skin.
• Construction workers are typically exposed to
  inorganic lead
• paints as pigments such as lead oxide or lead
  carbonate.
• Not readily absorbed through the skin.

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Lead in the Body

• When lead enters the bloodstream it moves
  throughout the body and is either stored or
  eliminated.
• Lead storage occurs primarily in the
• Bones
• Soft tissue I.e., liver, kidneys and fat.
• This accumulation is referred to as the "body
  burden
• A worker can be affected by lead months or years
  after the initial exposures.
• Lead is slowly released back into the blood
  stream from storage sites such as organs or
  bones.

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Lead in the Body

• Lead can stay in the body for a long time
• For one half of the lead to leave it takes
• 25 days from the blood
• 40 days from other organs
• More than 25 years from the bone
• The body eliminates lead through the kidneys and
  colon.

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Effects of Lead Exposure
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Effects of Lead Exposure

• Lead can produce a variety of adverse health
  effects.
• Acute effects are those that appear shortly after
  a brief, high exposure.
• Chronic effects generally come from low to
  moderate exposures for a relative long period
• may also be suffered over time as lead levels
  gradually drop after a very high exposure.

Acute vs Chronic
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Acute Health Effects

• Very low lead exposures do not cause any
  short-term effects.
• Excessive exposures can lead to a variety of
  symptoms relatively soon after exposure occurs.
• Metallic taste in the mouth
• Abdominal pain
• Constipation
• Pain in the arms and legs
• Hypertension (high blood pressure)
• Vomiting

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Acute Health Effects

• Severe lead exposures can cause nervous system
  damage, with symptoms, such as
• Intoxication
• Coma
• Respiratory arrest
• Death.

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Chronic Effects

• Chronic adverse health effects generally occur
  after relative long exposures to moderate or low
  doses of lead.
• The symptoms include

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Heath Effects vs Symptomology

• Some workers may experience symptoms at lower
  blood lead levels while others may tolerate very
  high levels without showing symptoms
• Do not wait for sickness to occur before
  addressing the problem of lead exposure.

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Organs and Systems Affected by Lead
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Effects on the Blood (Circulatory System)

• Red blood cells contain hemoglobin

• iron-rich protein that carries oxygen from the
  lungs to all of the body's muscles and organs

• Lead interferes with the production of the
  hemoglobin.

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Effects on the Blood (continued)

• Anemia occurs when the number of red blood cells
  falls below normal
• Anemia is linked with symptoms, e.g.,
• Tiredness
• Weakness
• Headache
• Irritability

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Effects on the Blood (continued)

• As oxygen in the blood decreases, the body tries
  to compensate.
• The heart works harder
• Pumping more blood in an attempt to send more
  oxygen
• If the heart works too hard, it can develop a
  rapid heartbeat
• May result an enlargement of the heart muscle
  that in turn can lead to heart failure.

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Effects on the Nervous System

• The body system that is most effected by lead
  exposure
• The damage can be permenent
• Lead can affect the central nervous system (e.g.,
  the brain). The syptoms include
• Fatigue
• Nervousness
• Anxiety
• Sleeplessness.

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Effects on the Nervous System

• Damage to the brain may also result in behavioral
  problems, i.e.,
• Poor memory
• Visual disturbances
• Confusion
• Encephalopathy (a degenerative brain disease) may
  occur.

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Effects on the Nervous System

• Lead can affect the peripheral nervous system
  which, controls the movements of hands, fingers,
  and feet.
• Peripheral neuropathy
• Weakness and/or paralysis of the hands or legs
  can cause "wrist drop" or "foot drop".

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Effects on the Kidneys

• 65 of lead in blood is filtered in kidneys
• Lead can damage kidneys
• Often damage is not detected until its too late
• Can cause kidney failure

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Effects on the Reproductive System

• Female Reproductive Health and Pregnancy
• Reduces fertility
• Affects menstruation and menopause
• During pregnancy, body absorbs blood lead more
  quickly (50 of inhaled/ingested lead)
• Lead passes through placenta to fetus and may
  result in
• Brain damage to fetus
• Miscarriage or premature birth

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Effects on the Reproductive System (continued)

• Male Reproductive System
• Decreased libido
• Infertility
• Damage to sperm, decreased motility
• Increases spouses chance of miscarriage,
  premature birth, and birth defects in child

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Children and Lead

• Research has shown children to be especially
  vulnerable to lead.
• Their nervous system is still developing
• Lead damage at this early stage can
• Delay mental development
• Lower IQ scores
• Impaired hearing
• Affect balance

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Children and Lead

• Other effects associated with lead include
• Toxic effects on the kidney
• Impaired Vitamin D balance
• Red blood cell problems.

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Conclusion

• Lead enters the body through inhalation and
  ingestion.
• Results include both acute and chronic effects
• ranging from fatigue and abdominal pain to
  decreased sexual drive and even death.
• Many organs and systems can be affected,
• including the blood, nervous system, kidneys,
  liver and reproductive system.
• The most tragic damage can occur to children
  exposed to lead carried home by a parent.