2. 2
They put arsenic in his meat
And stared aghast to watch him eat;
They poured strychnine in his cup
And shook to see him drink it up:
They shook, they stared as white's their shirt:
Them it was their poison hurt.
• A.E. (Alfred Edward) Housman (1859–1936)
Quote
3. 3
Arsenic poisoning through the ages
Ancient Rome,
Chine, Persia,
Egypt,…
Pope Alexander
VI (1492-1503)
Mozart
(1756-1791)
King George III
(1738-1820)
President Zachary
Taylor (1784 -1850)
Napoleon
Bonaparte (1769-
1821)
Simón Bolívar
(1783–1830)
4. 4
A Therapeutic Agent and a poison for 2400 years ago in Greece and Rome.
Early Chinese texts recommended arsenic sulfides for making toxic smoke
bombs for mass poisoning of soldiers.
The Harmony policy ("gifts" of food laced with arsenic) was used by British
settlers in the 1840s to wipe out the famished aboriginal population in the
Manning River basin, Australia.
Lewisite was invented in 1904 by Julius Arthur Nieuwland, former Professor
of Chemistry at the University of Notre Dame. It later used in WWII.
Arsenic in warfare
5. 5
• The word arsenic comes from the Persian word Zarnikh, means "yellow“
• Atomic number: 33
• Atomic Mass: 74.92
• Metalloid (Semi-metallic) element
• Melting point: 817 °C
• Grey
• Most common As allotropes, stable
• Density: 5.73 g/cm3
• Semiconductor and brittle
• Yellow
• Density: 1.97 g/cm3
• Soft and waxy
• Volatile and toxic
• Black
• Glassy and brittle
• Poor electrical conductor
Physical characteristics
6. 6
• Arsenic (As) can exist in four oxidation states : -3, 0, +3 and +5.
As0, (metallic arsenic), only stable in very reduced conditions.
As³ˉ (Arsenide), like Arsine, AsH3, a by-product of electro-refining, highly toxic,
the most common oxidation state form.
As³+ (Arsenite, AsO3
3- ), like Arsenic trioxide, As2O3, known as ‘white arsenic’,
highly toxic.
As5+ (Arsenate, AsO4
3- ), like Realgar, Sb2As3, which is stable and
environmentally benign.
• As³+ and As5+ are soluble in the water to form acidic solutions.and highly toxic to
humans and the environment.
• As³+ is 500 times more toxic than As metal and As5+.
Chemistry
7. 7
Inorganic compounds:
Minerals with the formula MAsS and MAs2 (M = Fe, Cu, Ni, Co) together with
arsenic sulfide minerals and native arsenic.
Common Minerals: Orpiment (As2S3), Realgar (As4S4), Arsenolite (As2O3),
Arsenopyrite (FeAsS), Enargite (Cu3AsS4), Tennantite (Cu12As4S13), Niccolite
(NiAs)
More toxic and have been linked to cancer.
Organic compounds:
Arsenic also occurs in various organic forms in the environment.
Are found mainly in fish and shellfish. Less toxic than the inorganic arsenic
compounds and are not thought to be linked to cancer.
Arsenic compounds
8. 8
Agricultural:
Wood preservatives in treating wood products
Insecticides and Pesticides , e.g. lead arsenate on fruit trees
Chicken Feed to promote the growth of chickens
Medical use
To treat an uncommon blood cancer known as acute promyelocytic leukemia.
Alloys
Car batteries (lead components)
Semiconductors (gallium arsenide)
Military
Chemical warfare agents such as Lewisite (C2H2AsCl3), highly poisonous.
Glassworks industry
In our body:
A level of 0.00001% is needed for growth and for a healthy nervous system.
Applications
9. 9
Source:
Most arsenic is obtained as a by-product of processing gold, silver, copper, and
other metal ores.
In 2014, China was the top producer of white arsenic with almost 70% world
share, followed by Morocco, Russia, and Belgium.
Consumption vs Production:
Total consumption of inorganic Arsenic in 2010: 52,800 ton
Total production based on 16,100,000 tons of copper production and 0.5 wt% of
arsenic in the concentrate: 322,000 ton
Prices: $US (2011):
Arsenic trioxide: $0.42 -$0.51 per kilogram
99%-pure arsenic metal: $320 per 100g
Arsenic market
10. 10
Arsenic is a natural element that can be found in rocks, soil, water, air, and in
plants and animals and is the 53rd most abundant element. It is released into
the environment by:
• Naturally occurring sources:
Volcanic ash
Weathering of minerals and ores
Mineralized groundwater
Forest fire
• Human activates:
Mining activities
Smelting
Runoff from agriculture
Runoff from glass and electronics production
Coal-fired power plants
Industrial waste
Into the environment
11. 11
The International Agency for Research on Cancer (IARC) recognizes arsenic
and arsenic compounds as Class 1 carcinogens.
Arsenic toxicity
12. 12
Short-term effects can include:
Irritation of the skin, eyes, mouth, throat and lungs
Skin damage and inflammation
Stomach pain, diarrhea, vomiting
Internal bleeding from the stomach and intestines
Longer-term effects can include:
Damage to the inside of the nose
Skin colour changes and prolonged skin inflammation problems
Inflammation of the lungs
Damage to peripheral nerves, with numbness and loss of vibration sense in
particular
Problems with the heart and heart rate/rhythm
Death
Arsenic toxicity
13. 13
Intake of 70 to 300 mg of arsenic trioxide may be fatal.
Death occurs between 12 to 48 hours but can occur within one hour.
Constriction of the throat with difficulty in swallowing
Severe intestinal pain
Vomiting, diarrhea
Muscle cramps
Severe thirst
Shock, coma and death
Acute poisoning
14. 14
• Through food, water, and air:
In fruits, vegetables, grain products, fast foods, dairy products, and seafood
Breathing sawdust or burning smoke from arsenic-treated wood
Living in an area with high levels of arsenic in rock and ground water
Working in a job where arsenic is made or used
Human exposure
15. 15
A form of groundwater pollution due to naturally occurring high
concentrations of arsenic in deeper levels of groundwater.
The arsenic levels in natural waters range between 1-2 µg/L, although
concentrations can be significantly higher (up to 12 mg/L) in areas
containing natural arsenic sources.
A 2007 study found over 170 million people in more than 70 countries are
probably affected by arsenic poisoning from drinking water.
Arsenic in drinking-water causes 200,000 – 270,000 deaths per year from
cancer in Bangladesh alone.
Arsenic contamination of groundwater
16. 16
Groundwater arsenic contamination areas
The maximum arsenic concentration in drinking water allowed by the the
World Health Organization's standard of 10 parts per billion (ppb).
18. 18
Often found in sulphide minerals
Arsenic-bearing sulphide minerals are economically attractive in terms of
amount of Copper, Gold, and Silver they contain.
By-product of smelting for copper, lead, zinc
The ASARCO copper smelter in Tacoma, Washington, closed in 1985 – still
dealing with pollution issues .
Leaching is safer environmentally. However, disposal of the arsenic
containing raffinate further presents a challenge.
Arsenic in the mining industry
19. 19
High financial penalties are imposed by smelters to treat copper
concentrates containing As > 2000 ppm. The rejection limits for smelter is
0.5% As.
Penalty: US$3 per 0.1% As
Arsenic trioxide in the presence of acid water and reducing metals (such as
zinc, aluminium or galvanised steel) can generate arsine (AsH3) gas, which
can kill rapidly at 250 ppm, and prolonged exposures at 10 ppm can be
fatal.
Arsenic in the mining industry
20. 20
Avoidance of processing high-arsenic copper ore
(From Safarzadeh, et al ., 2014)
Arsenic
Issues
•Lack of market
for Arsenic and
its compounds
•Arsenic sulphide
and calcium
arsenate no more
acceptable to
dispose
•Difficult to filter
precipitates
•As oxidation to +5
state is needed
before
precipitation
•etc
Roasting
•Hazardous
working
environment
•Complexity of gas
and dust capture
and separation
•Low unit through-
put
•High fuel
consumption
•etc
Leaching
•Not amenable to
conventional
leaching
technologies
•Bacterial oxidation
still under study
•Not well
understood the
chemistry in
alkaline media
•High arsenic
concentrations
•etc
Flotation
•Difficult to
separate Arsenic
and non-arsenic
copper sulphides
•Similarity in
physicochemical
characteristics
•Selective oxidation
of flotation, pulp
control, selective
depressants and
collectors
•etc
Environmental
Issues
•Ground and
surface water
contaminants
•Arsenic emissions
upon roasting
•Requirement for
Safe storage of
final processing
residues
•Dissolved As in
aqueous stream
•Instability of final
arsenic product
•etc
21. 21
Arsenic is found in the ores and concentrates that are used in the
workplace.
Breathing in arsenic dust or fumes
Absorbing arsenic through the skin
Swallowing arsenic after handling food when you have arsenic dust or arsenic
compounds on your hands.
Arsenic in workplace
22. 22
Arsenic exposure is diagnosed through tests of blood, urine, hair and
fingernails, and chest X-ray exam.
• Health monitored
• Urine test
Most reliable method for identifying arsenic exposure in the past few days.
• Hair and fingernails test
Detect high-level arsenic exposures during the past 6 to 12 months
Examine the skin regularly, looking for colour changes, rashes and skin
damage.
• Chest X-ray exam
Health checks
23. 23
OSHA - Workplace air
The eight-hour time-weighted average exposure standard for arsenic
and its compounds (as As) is 0.05 mg/m³.
Immediate action must be taken to reduce the health hazard
If the exposure of the employee to the contaminant is approaching the
exposure standard of 0.05 mg/m3 (as As).
The biological monitoring indicates that the average urinary excretion
exceeds 220 micrograms of arsenic per gram of creatinine.
Exposure standards
24. 24
• Elimination
• Substitution
• Engineering
Such as substituting safer materials for more hazardous ones,
enclosing a process that could expose workers to hazards, or
ventilating a work area
• Work practices and other administrative controls
Such as changing clothes after work, washing work clothes regularly,
and keeping food out of the work area
• Personal Protective Equipment (PPE)
Such as gloves and respirators, as part of a workplace protective
program
Hierarchy of controls
25. 25
• Work practices
• Use of appropriate personal protective equipment (PPE)
• Wash your hand before drinking, eating or smoking
• Use the separate change room, and clean lunch area
• Don’t take your work clothing and boots home
• Dispose or have protective clothing laundered
• Keep your street clothing in a clean place
• Clean your respirator daily and store it in a clean and dry area
How to protect yourself
26. 26
• Don’t remove dust by blowing down or shaking out your clothing.
• Take a shower at the end of the shift when required.
• Don’t dry sweep or blow down dust containing arsenic,
• Use exhaust ventilation when sawing or sanding arsenic-treated
wood.
• Use a vacuum with high efficiency filters for clean-up
• Proper control of PPE removal
How to protect yourself
27. 27
• Coveralls or similar full-body work clothing.
• PVC or rubber gloves, and shoes or coverlets.
• Impervious gloves, aprons and face shields or splash goggles where liquids
are being processed in a manner that may result in splashes.
• Impervious clothing for employees subject to exposure to arsenic trichloride.
• Appropriate respiratory protective equipment for the concentration of arsenic
that may be in the air.
Personal Protective Equipment (PPE)
28. 28
• Agency for Toxic Substances and Disease Registry (ATSDR). Public Health Statement for
Arsenic. 2007
• Who 2011. Guidelines for drinking-water quality. Fourth ed.: World Health Organization
• Environmental Health Perspectives, 2005, 113, A379
• International Agency for Research on Cancer (IARC). IARC Monographs on the
Evaluation of Carcinogenic Risks to Humans. Vol. 84: Some drinking-water disinfectants
and contaminants, including arsenic. 2004.
• Agency for Toxic Substances and Disease Registry (ATSDR). Case Studies in
Environmental Medicine: Arsenic Toxicity. 2010.
• Frumkin H, Thun MJ. Arsenic. CA Cancer J Clin. 2001;51;254-262.
• International Agency for Research on Cancer. IARC Monographs on the Evaluation of
Carcinogenic Risks to Humans. Volume 100C: Arsenic, Metals, Fibres, and Dusts. 2012.
• Mead MN. Arsenic: In search of an antidote to a global poison. Environ Health Perspect.
2005;113(6):A378-A386.
• US Department of Health and Human Services. Public Health Service, National
Toxicology Program. Report on Carcinogens, Twelfth Edition. 2011.
References
29. 29
Thank You
Questions?
Tayebi-Khorami, Maedeh, June 2015, presented at monthly safety meeting at Julius
Kruttschnitt Mineral Research Centre (JKMRC), Sustainable Minerals Institute (SMI), The
University of Queensland
Email: m.tayebikhorami@uq.edu.au