DEPARTMENT OF GEO-RESOURCES AND GEOTECHNICAL ENGINEERING

Online search on object:Occurrence of Heavy Metals and Its Hazard

In Groundwater In Cambodia

Introduction by Professor: PICH BUNCHOEUNPrepared by: KONG SOTHEARA

2016-2017

Outline Presentation

I. IntroductionII. Definition of Heavy MetalsIII.Common Heavy Metal and Its properties:

Nature: Physical and chemical properties Sources Occurrences Health Effects Applications

IV.Summary

I. Introduction

II. Definition of Heavy Metals

Heavy metals: Are metal that have density more than

5g/ml. Toxic in a very small concentration in

nature.4 Commons Heavy metals in the world:

Mercury (Hg) Cadmium (Cd) Arsenic (As) Lead (Pb)

III. Common Heavy Metals and Its Properties:

Nature: Physical and Chemical Properties Sources Occurrences Health Effects Applications

1. Mercury (Hg) General Information:

Chemical Symbol: Hg Color: metal, silver Liquid in room temperature (over 20°C) High density (5.43 g/cm³) High Surface tension Breaks up easily into many small droplets Dissolves some metals giving amalgams (These include silver, mercury, tin and copper)

Slightly soluble in water Naturally Occurring Expands and contract evenly with temperature

changes Flammability class: non-combustible liquid

Physical Properties Atomic mass average: 200.59 Boiling point: 357oC / 675oF / 630K Electrical conductivity: 0.0104 X 106 / cm Ohm Thermal conductivity: 0.0834 W / cmK Density: 13.546 g / cm3 @ 300K Melting point: -38.72oC / -37.7oF / 234.28K Molar volume: 14.81 cm3 / mole Vapor pressure: 0.0002Pa @ -38.72oC Heat of vaporization: 59.229 kJ / mol

Chemical Properties: Valence states: elementar Hg0, mercurous

Hg+1, mercuric Hg+2 . Most stable form: elementar mercury Thermally unstable both forms Hg+1, Hg+2,

decompose to elemental mercury. Ionic forms: Hg2

2+, Hg2+

inorganic mercury mainly in a form of salts, mostly weak soluble in water.

Sources of Mercury (Hg) Volcanoes Forest fires Cinnabar (ore) Fossil fuels such as coal and petroleum. Levels of mercury in the environment are

increasing due to discharge from hydroelectric, mining, paper industries.

Occurrences Human-made products and energy production

sources Mercury compounds used as disinfectants,

fungicides and pesticides. Organic compounds can be chemically

synthesized Free-mercury can convert into methyl mercury

in the presence of micro-organism Methyl mercury, which is fat - soluble, bio - accumulates in the tissue of fish.

In soil form atmospheric depositions In atmosphere by vaporization from water

and land media through the groundwater. Coal-fired boiler utilities and waste

(medical and municipal) combustor emission.

Health Effect Toxicity of mercury and its compounds

Absorption through the lungs, skin and stomach

Most toxic of all organic forms are methyl or di-methyl mercury

Inorganic compounds can be irritating or corrosive to the skin, eyes, mucus membranes

Swallowed compounds can cause nausea, vomiting, diarrhea and kidney damage

Acute Health Effect Very high exposure to mercury vapor in air

can cause acute poisoning Symptoms usually begin with cough, Chest tightness and breathing difficulty Direct exposure to mercury vapor can

cause discoloration of lens in the eye.

Chronic Health Effect Uncontrollable tremor (shaking) of the hands,

tongue or eyelids Trouble balancing and walking Wide swings of mood, easily irritated fright,

depressed, excited for non apparent reason Hallucinations Memory loss Inability to concentrate Gum become soft and spongy, loosen teeth Cause birth defects in children born of exposed

mothers

Application Used in batteries Fluorescent lights Felt production Thermometers and barometers Use to fill teeth in medical

2. Cadmium (Cd) General Information

Symbol: Cd Atomic Number: 48 Color: Soft, bluish-white Average Concentration in Earth’s crust: 0.1 - 0.5 ppm Occur as a minor component in most zinc ores and is a byproduct of zinc production.

Physical Properties Soft, malleable, ductile, blush white divalent

metal Resistance to corrosion and used as a protective

plate on other metal Bulk metal that is insoluble in water and is not

flammable Its powders may burn and release toxic fumes

Chemical Properties Valence state: and Burn in air and form brown amorphous

cadmium oxide (CdO). Dissolve in Hydrochloric acid and forming

cadmium chloride (CdCl2 ) Dissolve in Sulfuric acid and forming cadmium

sulfate (CdSO4 ) Dissolve in Nitric acid and forming cadmium

nitrate (Cd(NO3)2 )

Electronegativity according to Pauling : 1.7 Density: 8.7 g.cm-3 at 20°C Melting Point: 321 °C Boiling Point: 767 °C Vader Waals radius: 0.154 nm Ionic radius: 0.097 nm (+2) Isotopes: 15 Electronic shell: [ Kr ] 4d10 5s2 Energy of first Ionization: 866 kJ.mol -1 Energy of second Ionization: 1622 kJ.mol -1 Standard Potential: -0.402V

Sources Mainly be found in the earth’s crust and always

in combination with zinc. Consists in the industries as an inevitable by-product of zinc, lead and copper extraction Enter to environment mainly through the

ground water because it is found in manures and pesticides.

Found in the rock and released into the river through weathering

Found in the flame of forest fires and volcanoes explosion and released into air.

Mining and metallurgical operations Electroplating industry Manufacturing PVC plastics Ni-Cd batteries, paints, pigments and dyes Fertilizers and pesticides Anti – Corrosive agent for steel, iron, copper brass and other alloys. TV screens.

Occurrence Earth’s crust: 0.1 mg kg−1 (ppm) Atmosphere < 5 ng m−3 Soil < 2 mg kg−1 Vegetation < 0.5 mg kg−1 Sea water < 50 ng L−1 Sediment < 2 mg kg−1 Greenockite (CdS),the only cadmium mineral

of importance, is nearly always associated with sphalerite (ZnS)

Health Effect Cause diarrhea, stomach pains and severe

Vomiting Itai – itai disease – bone fracture Kidney dysfunction – chronic renal failure Reproduction failure and even infertility Damage to the central nervous system Damage to the immune system Psychological disorders DNA damage or cancer development

Environmental effects of cadmium Cadmium – rich sludge can pollute surface

waters as well as soils. Cadmium strongly absorbs to organic matter in

soils. Cadmium can accumulate in the plant eating

animals, especially when they eat multiple plants.

In aquatic ecosystems, cadmium can bioaccumulation in mussels, oysters, shrimps, lobsters and fish.

Application Batteries: Cadmium is used predominantly in rechargeable nickel-cadmium batteries 1.2 V. Electroplating:Is used in the aircraft Industry to reduce corrosion of steel components.

Nuclear fission: Cadmium is used in the control rods of nuclear reactors, acting as a very effective “neutron poison” to control neutron flux in nuclear fission.

Compounds:–Cadmium oxide was used in black and white

television and in cathode ray tubes–Cadmium sulfide used in paint.

Laboratory uses: Helium-cadmium lasers are a common source

of blue-ultraviolet laser light Cadmium compound can be used for light

detection in solar cells ( HgCdTe )

Review Heavy metals: Are metal that have density

more than 5g/ml. Common Heavy metals: Mercury (Hg),

Cadmium (Cd), Lead (Pb), Arsenic (As) Mercury (Hg)• Sources: flame and cinnabar ore• Effects: lungs, skin, stomach , eye, mucus

membrane ,nausea ,vomiting ,diarrhea and kidney, chest tightness, brain, birth defect.

Cadmium (Cd)• Sources: combination with zinc ore in earth

crust, industries, poisoning product, rocks, flame, batteries, paints, pigments, dye, fertilizers, pesticide, some alloys.• Effect: diarrhea, stomach pains, severe

Vomiting, Itai-Itai disease(bone fracture), kidney, central nervous system, immune system, psychological disorders, DNA damage, Cancer development, environment.

3. Lead (Pb) Physical Properties:

Appearance metallic gray in color High Density Good corrosion resistance High ductility Lubricating properties

Chemical Properties Phase: Solid Standard atomic weight: 207.2 Density(Near R.T): 11.34 g.cm-3 Liquid density (At M.P): 10.66 g.cm-3 Density (normal): 11.34 g.cm-3 Melting Point (Celsius): 327.35 Boiling Point (Celsius): 1740.0 Crystal structure: Cubic Closed packed Atomic number: 92

Sources Industrial discharges from smelters and

battery manufacturing units Solders in electronics Sewage effluent Atmospheric fallouts from fossil fuel

burning Building industry for soundproofing

Occurrences Not very abundant Important lead minerals are: •Galena (PbS): 86% of Lead•Anglesite (PbSO4): 68% of Lead• Cerussite (PbCO3): 77% of Lead

Other lead minerals are:• Linarite (PbCu[(OH)2|SO4])• Pyromorphite (Pb5(PO4)3Cl)•Mimetite (Pb5(AsO4)3Cl)

•Vanadinite (Pb5(VO4)3Cl)•Wulfenite (PbMoO4 )

The main deposit mineral located in:•USA, Spain • Peru, Italy•Argentina, Serbia• Zambia• South Africa•Germany, Sweden

Health Effect A general metabolic poison Acute exposure: Kidney damage Chronic Exposure: Interstitial nephritis of

kidney Inhibits hemoglobin synthesis and cause

anemia Inhibits enzyme activity Neurological and reproductive dysfunctions

4. Arsenic General Information

Symbol: As Atomic Number: 33 Color: Ordinary gray and steel gray Density: 5.73 Family: group 15 (VA) Nitrogen Found in rock or ores in the earth’s crust In water, arsenic has no smell or tasted and can only be detected through a chemical test.

Physical Properties Common form: shiny, gray, brittle, metallic-looking solid. Less common form: yellow crystalline solid. Not melt (in normal condition) but change

directly into a vapor (gas) when getting heat ( This process called sublimation) Can be forced to melt under high pressure

at about 814°C (1,500°F)

Chemical Properties Electronegativity according to Pauling: 2.0 Melting point: 814 °C (36 atm) Boiling point: 615 °C (sublimation) Vander Waals radius: 0.139 nm Ionic radius: 0.222 nm (-2), 0,047 nm (+5),

0,058 (+3) Electronic shell: [ Ar ] 3d10 4s2 4p3

Energy of first ionization: 947 kJ.mol -1

Energy of second ionization: 1798 kJ.mol -1

Energy of third ionization: 2736 kJ.mol -1

Standard potential: - 0.3 V (As3+/ As ) Arsenic is a metalloid Heated in the air and combines with oxygen to

form a blue flame [Arsenic oxide (As 2 O 3 )] Combine slowly with oxygen at room

temperatures. Not dissolve in water or most cold acids React with some hot acids to form arsenous acid

(H3 AsO3 ) or arsenic acid (H3 AsO4 ).

Sources Pesticide, herbicide Combustion of coal Mining, smelting of goal, lead, copper, and

nickel Leachate from abandoned gold mines Tobacco smoke

Occurrences Rarely occurs as a pure element (compound) Common ores of arsenic: •Arsenopyrite (FeAsS), •Orpiment (As 2 S 3 ) • Realgar (As 4 S 4 )

In earth’s crust: 5ppm The world’s most largest producers: China,

Chile, Mexico, Belgium, Namibia, and the Philippines ( The us does not )

Health Effect Birth defects Carcinogen: Lung cancer, cancers of the

bladder and kidneys Gastrointestinal damage Severe Vomiting Diarrhea Death Concentrate within the internal organs, skin,

hair, urine and lead to disease.

IV. Summary

Heavy metals: Are metal that have density more than 5g/ml.

Common Heavy metals: Mercury (Hg), Cadmium (Cd), Lead (Pb), Arsenic (As)

Mercury (Hg)• Sources: flame and cinnabar ore• Effects: lungs, skin, stomach , eye, mucus membrane ,

vomiting ,diarrhea and kidney, chest tightness, brain, birth defect.

Cadmium (Cd)• Sources: combination with zinc ore in earth crust,

industries, poisoning product, rocks, flame, batteries, paints, pigments, dye, fertilizers, pesticide, some alloys.

• Effects: diarrhea, stomach pains, severe Vomiting, Itai-Itai disease(bone fracture), kidney , central nervous system, immune system, Psychological disorders, DNA damage, Cancer development, environment.

Lead (Pb)• Sources: Industry discharge, Solders flame, sewage

effluent, flame.• Effects: metabolic poison, kidney damage, Interstitial

nephritis of kidney Inhibits hemoglobin synthesis and cause anemia, Inhibits enzyme activity, Neurological and reproductive dysfunctions.

Arsenic (As)• Sources: pesticide, herbicide, Combustion of coal,

smelting of goal, lead, copper and nickel , Leachate from abandoned gold mines, wood preservative, Tobacco smoke.

• Effects: birth Defects, Carcinogen (lung cancer, caners of the bladder and kidneys), Gastrointestinal damage, severe Vomiting, Diarrhea, Death, Concentrate within the internal organs, skin, hair, urine and lead to various disease.

REFERENCES[1] INTERNATIONAL JOURNAL OF TECHNOLOGY ENHANCEMENTS AND EMERGING RESEARCH, VOL 3, ISSUE 02, ISSN 2347-42889 (2015)[2] WATER STEWARDSHIP INFORMATION SERIES, FEBRUARY 2007, BRITISH COLUMBIA.[3] ARSENIC IN CAMBODIA, RDI [Resource Development International Cambodia (2011)], [ASK ME ABOUT ADVANTURES !] LINK: https://djpolzin23.wordpress.com/2010/08/10/hello-world/#respond

[4] http://www.uwm.edu.pl/kchem/mercury/mercury.html#toxicity[5] https://en.wikipedia.org/wiki/Cadmium#Physical_properties[6] http://www.chemistryexplained.com/elements/A-C/Arsenic.html[7] http://www.lenntech.com/periodic/elements/pb.htm[8] http://www.ncbi.nlm.nih.gov/books/NBK158769/[9] http://www.lenntech.com/periodic/elements/cd.htm[10] http://www.polywellnuclearfusion.com/CarbonWillKillUs/CoalPollution.html

[11] http://www.intechopen.com/books/current-perspectives-in-contaminant-hydrology-and-water-resources-sustainability/occurrence-and-mobility-of-mercury-in-groundwater[12] http://meganandtehmeedah.blogspot.com/2013_03_01_archive.html[13] https://www3.epa.gov/airtoxics/hlthef/cadmium.html[14] http://www.slideshare.net/biotechvictor1950/heavy-metal-contamination-of-global-environment

[15] http://envirocivil.com/health-and-wellness/health-hazardous-cadmium/[16] http://nautilus.fis.uc.pt/st2.5/scenes-e/elem/e08220.html[17] http://image.slidesharecdn.com/leadanditsalloysfinalprint-121208114901-phpapp01/95/lead-and-its-alloys-2-638.jpg?cb=1354967414[18] http://www.slideshare.net/anurudhahwn/lead-and-its-alloys