This slide includes- * Types of arsenic and merury * Their health effect * Diseases due to arsenic and mercury poisoning * Treatment

1. Heavy Metal Toxicity
Mercury and Arsenic

2. Prepared by-
Khandaker Abir Hasan
Department of Pharmacy
Noakhali Science and Technology University
Noakhali, Bangladesh

3. Introduction
What are heavy metals?
Heavy metals are naturally occurring elements that have a high atomic weight
or density and are toxic or poisonous at low concentrations.
Example: Mercury, Lead, Arsenic, Cadmium etc.
Mercury Lead CadmiumArsenic

4. Properties of heavy metals
Can be metal or metalloid (eg. Arsenic)
They occur near the bottom of the
periodic table
Their standard state have density of
more than 5 g/cm3
Toxic in nature
Non biodegradable

5. Mercury

6. Introduction
 Atomic number 80
 Liquid at room temperature (20-25˚ C)
 Most volatile of all metals
 Highly toxic in vapor form
 Liquid mercury is not highly toxic and most
of that ingested is excreted

7. Source
Source of MercuryNatural
Volcanoes
Forest fires
Fossil fuels
Man made
Power plant
Pulp and paper
industries
Combustion of coal
and medicinal
waste
Manufacture of
metal, alkali and
cement

8. Types
Types
Elemental
Inorganic
Organic
Inorganic
Liquid mercury
Mercuric chloride (HgCl2),
Mercuric sulfide (HgS)
Methyl Mercury
Example
Example
Example

9. Risk factors
Elemental Mercury:
Most common form
It is metallic, silvery liquid
Easily vaporize in room temperature into an
odorless, colorless vapour that can easily inhaled
Risks:
 Easily crosses blood/brain and placental barriers and can enter breast milk
 Potent neurotoxin
 Neurological effects- tremors, mood swings, irritability
 Very high exposure can cause kidney effects, respiratory failure and death

10. Risk factors
Inorganic Mercury:
White in color except cinnabar (red)
Least toxic of three forms
Enters body through mouth and skin
from disinfectant and fungicide
Usually used in science lab
Risks:
 It can damage the GI tract, as well as the kidneys and nervous system
 High exposures can lead to skin rashes, dermatitis, memory loss, mental
disturbance, and muscle weakness.

11. Risk factors
Organic Mercury:
Most commonly found organic mercury is methyl mercury and it
is the most toxic form of mercury
Converted from its inorganic form by biological bacterial process
Bio accumulates in environment most commonly found in fish
Ingestion of fish is most common route of human mercury
exposure
Risks:
 Birth defects
 Neurological problems
 Impairment of vision, speech, walking
 Extreme exposure leads to death

12. Effects of Mercury
Health effects:
 Mercury exposure at high levels can harm the –
 Brain, heart
 Kidneys, lungs
 Immune system of people of all ages
 High levels of methyl mercury in the bloodstream of unborn babies and young
children may harm the developing nervous system.
 Make the child less able to think and learn.

13. Effects of Mercury
Ecological effects:
 Birds and mammals that eat fish are more exposed to mercury than other animals
in ecosystems.
 Similarly, predators that eat fish-eating animals may be highly exposed.
 At high levels of exposure, methylmercury’s harmful effects on these animals
include:
 Death, reduced reproduction
 Slower growth and development, abnormal behaviour

14. Exposure of Mercury
 Mercury in the air eventually settles
into water or onto land where it can be
washed into water.
 Once deposited, certain micro-
organisms can change it into
methylmercury.
 This highly toxic form of mercury
builds up in fish, shellfish and animals
that eat fish.
 Methyl mercury builds up more in
some types of fish and shellfish than
others.
 Fish and shellfish are the main sources

15. Exposure of Mercury
 Another common exposure to mercury that can be a concern is breathing
mercury vapour.
 These exposures can occur when elemental mercury or products that contain
elemental mercury break and release mercury to the air.
 Particularly in warm or poorly ventilated indoor spaces.

16. Diseases
Minamata disease:
Minamata disease, sometimes referred to as
Chisso-Minamata disease, is a neurological
syndrome caused by severe mercury
poisoning.
Symptoms:
General cases
 Muscle weakness
 Damage to hearing, vision and speech
 Crippling hands and feet
Extreme cases
 Paralysis
 Coma
 Death

17. Diseases
Pink disease:
Methylmercury exposure in children may result in acrodynia in
which the skin becomes pink and peels and that is called pink
disease.
Symptoms:
 Irritability
 Neurosis
 Photophobia (light sensitivity)
 Hyperhidrosis (excessive sweating)
 Hypotonia (low muscle tone)
 Ataxia (lack of co-ordination)

18. Diseases

19. Treatment for Mercury poisoning
Chelation therapy:
 Chelation therapy is the administration of chealating agents which bind mercury
ions and facilitate their excretion through urine and feces.
 Approved chelating drugs for mercury poisoning include-
 Succimer (DMSA, 2,3-dimercaptosuccinic acid) is taken by mouth
 Dimercaprol (British Anti-Lewisite, BAL) is given by injection
DMSA BAL

20. Treatment for mercury poisoning
Medicinal
charcoal:
Mercury absorbs with charcoal’s surface and hence gets
removed without being absorbed by enterocytes.
Dialysis
:
If kidneys show signs of damage, alkaline fluids;
peritoneal dialysis or hemodialysis may be necessary.

21. Prevention for Mercury poisoning
 Mercury poisoning prevention at home
People of all over use some products as their daily driver. They are advised to read
the labels on products to see if they contain mercury, have warning labels about
potential threat.
 Mercury Poisoning Prevention - Amalgam Fillings
Mercury can be found in dental amalgam fillings.
There are several types of dental filling material that
can be used so individuals are urged to discuss choices
for dental fillings with their dentist.

22. Prevention for Mercury poisoning
Mercury Poisoning Prevention - Fish and Shellfish
 1. Abstain from consuming shark, swordfish, king mackerel, or tilefish because they
contain high levels of mercury
 2. Eat up to 12 ounces a week of a variety of fish and shellfish that are lower in
mercury
 3. Another commonly eaten fish, albacore ("white") tuna has more mercury than
canned light tuna and we have to cast aside this one while taking food
Mercury Poisoning Prevention - Vaccines
People are now concerned at the use of thimerosal, a mercury-containing preservative
used in vaccine preparations. However, the amount of mercury in thimerosal is very
low. In 2008, the CDC recommended that current flu vaccines are safe to use in
pregnant women and children because they contain very little mercury traces.

23. Arsenic

24. Introduction
 Arsenic is a chemical element with the symbol As
and atomic number 33
 It is a metalloid
 It has a specific gravity of 5.7 g/cm3
 It has various allotropes existing in both gray and
yellow crystalline forms.
Atomic Number : 33
Atomic Weight : 74.9
Oxidation States : -3,+3,+5

25. Source
Sources of arsenic are classified into 2 types. They are-
1. Natural Sources
 Rocks And Soil
 Water
 Forest Fire
 Air
 Fish ,Vegetables, Fruits
 Earth’s Crust
2. Industrial Process
 Glass Manufacturing
 Semi-Conductor (Gallium Arsenide)
 Fossil Fuel
 Smelting and Coal fine power plants

26. Types
 Arsenic is classified into 2 types. They are -
Arsenic
Inorganic
Arsenic
Organic Arsenic
Example-
Arsenic Trioxide
Sodium Arsenic
Toxic
Non-Toxic
Example-
Arsenobetine
(Seafood)

27. Health effects
Death
Birth
Defect
Birth
Defect
Diarrhea
Severe
Vomiting
Carcino-
genesis
Gastro-
intestinal
Damage
Health
Effect

28. Mode of action
 Arsenic interferes with cellular respiration by combining with the sulfhydryl
groups (-SH) of mitochondrial enzymes.
It particularly targets vascular endothelium leading
to increased permeability, tissue edema and
hemorrhage, especially in the intestinal canal.

29. Mode of action
 It replaces phosphorus in bones where it may remain for years.
 Locally it causes irritation of the mucous membranes and remotely depression of
the nervous system.
 Arsenic also interferes with glycolysis.

30. Absorption and excretion
 It can be inhaled and absorbed through the skin or through GIT after ingestion.
 Once absorbed, arsenic rapidly combines with the globin's portion of
hemoglobin and therefore localize in the blood. Within 24 hours it distribute to
liver, kidney, spleen, lung and GI tract with lesser accumulation in the muscle and
nervous tissue.
Absorption:
Excretion:
 Excreted mainly through kidneys as methylated arsenic and some part by faeces,
sweat, bile.
 It becomes fixed in cancellous tissue or bones. Replaces phosphorus.

31. Diseases
Acute
•Anemia
•Cholera
•Skin pigmentation
•Garlic smell
Chronic
•Hyperkeratosis
•Mees line on
fingernails
•Black foot disease
•Hepatic and renal
damage

32. Symptoms
Acute as poisoning-
o Nausea
o Vomiting
o Blood in the urine
o Cramping muscle
o Hair loss
o Stomach pain
o Loss of appetite
Chronic as poisoning-
o Vitamin A deficiency
o Skin color change
o Eye inflammation
o Cardiovascular disease
o Diabetes

33. Black foot disease and symptoms
Symptoms:
 Formation of black pustules on the feet
 The pustules can be very painful
 A foul odor

34. Treatment
 Consumption of only arsenic free water.
 Zinc, Selenium and Vitamin A for repair of the damaged skin.
 For Gastric Lavage, 1% Sodium Thiosulphate in water is helpful.
 Hemodialysis is the line of choice in massive arsenic poisoning.
 Purgatives like castor oil and magnesium sulphate is administered to diminish
intestinal absorption of arsenic poisoning.
 Blood transfusions and exchange transfusions may help the patient.

35. Medication
Medicines used to treat arsenic poisoning :
1. Dimercaprol ( BAL)
 Intravenous Injection
 Drug Class : Antidote, Chelating agent
 Side Effects: Rise in BP, Tingling, Headache and
Anxiety
 Dose : 3-4 mg/kg; 4 hourly for 2 days, 6 hourly for 1
day.

36. Medication
2. Succimer
 Orally effective tablets / capsules
 Drug class : Antidote, Chelating agent
 Side effects : Nausea, Anorexia and loose motion
 Dose : 10mg/kg : Every 8 hourly for 10 days

37. Prevention
Arsenicosis, as a public health problem, is a comparatively recent concept, for
which effective treatment measures are still not known. So it is a good decision to
prevent arsenic instead of medication after disease.
1. Identification of unsafe water sources:
Identifying the existing water sources having
arsenic concentration above the maximum
contaminant level (0.010 ppm or 0.010 mg/L)
Paint tube wells or hand pumps with different
colors.

38. Prevention
2. Methods of removal of arsenic from the arsenic
contaminated water:
Install arsenic removal
systems– either centralized
or domestic. Technologies
for arsenic removal include
oxidation, coagulation-
flocculation, absorption, ion
exchange, and membrane
technologies.

39. Prevention
3. Development of alternative sources of arsenic-free water:
Since arsenic removal technologies are all in their development phase and yet to become
fully reliable, it becomes imperative to search for alternate safe sources.
 Surface water-based alternate sources can be pond, sand filters, rainwater
harvesting, or piped water supply
 Ground water-based techniques can be either dug wells or deep tube wells from safe
aquifers.
Well Sand filter Rainfall water collection

40. Social awareness on Arsenic poisoning
Increasing awareness of the community regarding this deadly disease arsenicosis by
following way-
 Drinking water should be clean
 Make sure that all foods are prepared with clean water
 Safe water supply for irrigation of food crops
 Smoking should be prohibited.

41. Social awareness on Mercury poisoning
 Should avoid certain fish & seafood which have high level of mercury such as
shark, swordfish.
 Consumption food should be mercury free.
 Drinking water should be mercury free.
 Have to take medicine sufficient which contain mercury.
 Have to telecast the bad effect & safety side on mercury toxicity.

42. Conclusion
Both of the Hg & As have some bad effect on environment & human life. To
get a beautiful life man should rise social awareness on Hg & As toxicity. This
process may be avoided smoking & heavy metal containing food & may be
taken pure water which has no Hg & As. Finally, we can say that As & Hg are
not main matter, the matter is to change our mentality. By changing our
mentality we can ensure safety in our life on heavy metal toxicity.