Mercury toxicity

1. MERCURY TOXICITY

2.  Toxicity
 Source
 Human action
 Side effects
 Adverse effects
Contents

3.  Mercury poisoning (also known as
hydrargyria or mercurialism) is a type of
metal poisoning caused by exposure to
mercury or its compound mercury (Hg).
 Mercury is a heavy metals means a metal
of relatively high density, or of high
relative atomic weight.
 Heavy metal occurring in several forms,
all of which can produce toxic effects in
high enough doses.
INTRODUCTION

4. More about Mercury
 Mercury, or quicksilver, was known in ancient times as
hydrargyros, hence it’s chemical symbol ‘Hg’.
 Mercury is the only metal that is liquid at room
temperature and pressure.
 Mercury is an extremely rare element, but occurs in
deposits throughout the world mostly as cinnabar (or
mercuric sulphide).
 Like water, mercury can evaporate and become airborne.
 Because it is an element, mercury does not break down
into less toxic substances.
 Once mercury escapes to the environment, it circulates in
and out of the atmosphere until it ends up in the bottoms
of lakes and oceans.
 Mercury can be found as the elemental metal or in a wide
variety of organic and inorganic compounds.
 Depending on its chemical form, mercury may travel
long distances before it falls to earth with precipitation or
dust.

5. Uses of Mercury
 Felting and Hat-making
 Fluorescent lamps
 Mercury batteries
 Thermometers and thermostats
 Vacuum pumps,
 Barometers,
 Electric rectifiers and switches
 Printer and photocopy toners.
 Mercury-vapor lamps (for sterilizing water and
instead of steam in boilers
 of some turbine engines.)
 Amalgamation (to dissolve silver or gold to form
an amalgam, as in tooth fillings) This process has
been largely supplanted by the cyanide process, in
which gold or silver is dissolved in solutions of
sodium or potassium cyanide.

6. Sources of Mercury
 Non-ferrous metal manufacturing, mining
and alumina production are the largest
sources of mercury emissions.
 Precious metal mining (which can emit
mercury to water or land),
 Cement manufacturing (which may emit
mercury into the air) and
 Chemical manufacturing, which can emit of
mercury to land and into water.
 Fossil fuel power plants may also emit
mercury into the air by burning fuels such as
coal, oil, and petrol.
 Our landfills and sewage also contribute to
mercury being released into our soil and
water.
 Small amounts of mercury can be released
into the air in the exhaust fumes of cars,
buses and motorbikes.

7. Relative sources of mercury exposure
0
20
40
60
80
100
90
75
30
10
4
AMALGAM VACCINES SEAFOOD INDUSTRY OTHER

8. EXISTS IN THREE CHEMICAL FORM
 Elemental mercury
 Inorganic mercury
 Organic mercury

9. Most volatile .
Exist in liquid/vapor form.
Inhaled and absorbed into
lungs(80%) and GIT(0.01%) and
can cross the blood brain barrier
or reach the placenta.
Most common form amalgam
restoration.
Exposure to this form can occur
due to accidental spillage of
mercury in dental office.
Elemental mercury is used in
thermometers, barometers, and
pressure-sensing devices.

10. Normally mined as inorganic sulfide ore
Mainly in liquid form
 Can also exist in other form than sulfide
 Irritating in nature
 Main route of entry is through lung(80%)
Due to absence of fully formed blood brain barrier
it has been found in neonatal brain.
Inorganic mercury form complexed with gluthione
in the liver and secreted in the bile cysteine
mercury or gluthione mercury complex.
Inorganic mercury was used in the past in
laxatives, skin-lightening creams and soaps, and in
latex paint.

11.  Mainly in the form of methyl
mercury (CH3Hg+ )
 Main route of entry is absorption
though GIT(95-98%) though food.
 Used in fungicide and
pesticide.
 Found in vegetables , fruits
and grains.
 Toxic in nature.

13. Effects on Humans
 Depending on its chemical form
(elemental, inorganic or organic)
mercury is able to cause a myriad of
adverse health effects including :
 Neurotoxicity (elemental mercury,
methyl-mercury),
 Nephrotoxicity (elemental mercury,
mercuric salts such as mercuric
chloride),
 Teratogenicity (methyl-mercury) –
abnormalities in physiological
development, including birth defects
 Death (elemental mercury, methyl-
mercury).

15. ALLERGY
Allergy responses represent an
antigen-antibody reaction marked by
itching, rashes, sneezing, or other
symptoms
Contact dermatitis or Comb's type IV
hypersensitivity reaction represent
the most likely physiologic side effect
to dental amalgam

16. TOXICITY
TOXIC EFFECT ON MERCURY
FORM OF
MERCURY
ELEMENTAL INORGANIC METHYL
MERCURY
ROUTE OF
EXPOSURE
INHALTION ORAL ORAL –FISH
CONSUMPTION
TARGET ORGAN CNS , Kidney
Peripheral nervous system
KIDNEY, PNS CNS
LOCAL CLINICAL SIGN Lung ;bronchial irritation GI-irritation
Skin – irritation
ulceration
SYSTEMIC
EFFECTS
Kidney-proteinuria
CNS –mood change
PNS - Tremors
Kidney – proteinuria,
Tubular necrosis
Is PNS
TREMORS
NUMBNESS
Developmental
Effects in fetus
And newborn.
CNS IN ADULT
TREMORS
PARAESTHESIA

17. PSYCHOLOGICAL DISTURBANCES
 Fits of anger
 short term memory loss
 low self –esteem
 loss of self control
 sleepiness.
A person may also suffer from the loss
of ability to learn new thing or things
that require memorization

18. ORAL CAVITY PROBLEMs
 Inflammation of the mouth
 loss of bone around teeth
 ulcerated gums and other
areas in the mouth
 Darkening of gums
 taste of metal
 Bleeding gums

19. RESPIRATORY PROMBLEMS
-Weakness and problems with breathing
- Emphysema
-persistent cough
NEUROLOGICAL PROBLEMS
-headaches
-vertigo
-tinnitus
- twitching in various areas of the body
(eyelid, feet etc.)
G.I.T PROBLEMS
-Cramps
-inflamed colon
-diarrhea
C.V.S PROMBLEMS
-Weak pulse
-increase B.P
-Chest pain/feeling of pressure
in the chest area

20. Hg Damage Development of CNS In The Fetus During The Prenatal
period

21. Mercury poisoning can result in several
diseases, including:-
 Acrodynia (pink disease)
 Hunter- Russell syndrome
 MINAMATA DISEASE

22. Acrodynia (Pink disease)
 Considered to be a mercury allergy
 Erythema of the palms soles
 Edema of hand and feet
 Desquamating rash
 Hair loss
 Diaphoresis
 Tachycardia, hypertension
 Photophobia
 Irritability,
Constipation/Diarrhea
 Anorexia
 Insomnia
 Poor muscle tone

23. HUNTER-RUSSELL SYNDROME
 Syndrome is characterized by
paresthesia,
 visual field constriction, ataxia,
impaired hearing, and speech
impairment.
 The term Hunter-Russell
syndrome derives from a study of
mercury poisoning among workers in a
seed packing factory in Norwich,
England in the late 1930s who breathed
methyl mercury that was being used as a
seed disinfectant and preservative.

24. MINAMATA DISEASE
Minamata disease is an example of organic toxicity.
In 1952 Minamata Bay, a factory discharged inorganic
mercury into the water. The mercury was methylated by
bacteria and subsequently ingested by fish.
In 1953 fisherman and farmers showed symptoms-
neurological damage and fetal deformity.
Disease diagnosed in 1956
- linked to fish consumption
 1957 fishing banned in area
1959- mercury identified as cause
1960 source identified
- factory effluent.

25. Symptoms were:-
1.ataxic gait
2.convulsions
3.numbness in mouth &
limbs
4.constriction in the
visual field
5.difficulty in speaking.

27. Adverse effects
Acute perioral and facial paresthesias
Visual-field constriction
Respiratory distress and nonspecific dermatitis
Babies exposed in utero are affected by low birth weight, seizure disorders, profound
developmental delay, incomplete visual loss (including tunnel vision) or total blindness,
and hearing loss.
Neurologic damage in the form of diffuse and widespread neuronal atrophy is most
severe in patients exposed in utero.
Even prenatal exposure at low concentrations can cause subtle, but detectable,
decrements in the areas of motor function, language, and memory.
Children so affected may have long-term stigmata, including motor impairment, visual
loss, hearing loss, developmental delay, and seizure disorders.

28.  Dental amalgam are still widely used by the dental profession in most
parts of the world.
 Some countries, like Sweden, Canada and Germany, UK have either
banned or imposed serious limitations on amalgam usage.
 WHO states mercury levels in biomarkers such urine, blood , hair do
not represent levels in critical organs and tissues.
 The American Dental Association Council on Scientific Affairs has
conclude that both amalgam and composite materials are considered
safe and effective for tooth restoration.
CONCLUSION