THE STUDY OF CONTAMINATED TOXIC HEAVY METALS OF TRAFFIC STREET DUST AND SOILS IN ERBIL CITY
Heavy Metals(Toxic Metals)
Transcript of Heavy Metals(Toxic Metals)
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Dr. Mahes Kundagol
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A metal is a chemical element that is a good conductor of both electricity and heat and forms cations and ionic bonds with non-metals.
A metal is an element, compound, or alloy
characterized by high electrical conductivity. In a metal, atoms readily lose electrons to form positive
ions (cations). Those ions are surrounded bydelocalized electrons, which are responsible for the
conductivity. The solid thus produced is held byelectrostatic interactions between the ions and theelectron cloud, which are called metallic bonds
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An element whose atoms are packed closely together by strong forces of attraction with freeelectrons moving around
Physical Properties:- Good conductor of electricity - High melting point- High thermal conductivity
- High density - Malleable- Ductile
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Element Percent by mass Atomic percent (calc.) Oxygen 65% 25.6% Carbon 18% 9.5% Hydrogen 10% 63% Nitrogen 3% 1.3% Calcium 1.5% 0.24% Phosphorus 1.2% 0.24% Potassium 0.2% 0.03% Sulfur 0.2% 0.04% Chlorine 0.70% 0.04% Sodium 0.1% 0.03% Magnesium 0.05% 0.01% Iron 3 g in men, 2.3 g in women Cobalt, Copper, Zinc, Iodine < 0.05% each
Selenium, Fluorine < 0.01% each
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Other elements necessary for human life are-
Manganese
Molybdenum
Nickel A small amount of chromium is necessary for proper
health.
Boron has been found necessary for optimal health inrats, so presumably it plays a role in humans as well.
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The elements needed for life are relatively common in theEarth's crust, and conversely most of the common elementsare necessary for life.
An exception is aluminium, which is the third most commonelement in the Earth's crust (after oxygen and silicon), but
seems to serve no function in living cells. Rather, it isharmful in large amounts.
Besides these elements that are necessary for life, our bodiescontain trace quantities of most other elements, including
some that are harmful, such as mercury, cadmium, and lead.
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The heavy metal refers to any metallic chemical element that has a
relatively high density and Is toxic or poisoness at low concentrations
.Examples of heavy metals include (Hg),cadmium(Cd).,Arsenic (As),
chromium(Cr) Thallium(TL) and Lead(PB).
Heav metals are natural components of the Earth's crust. They cannot be
degraded or destroyed. To a small extent they enter our bodies via food,
drinking water and air as trace element
essentialto maintain the metabolism oflhe human body.However,et
hlghermncentrallans IIley Olin lead to pglaan!ng. Heavy metalpoisoningmu!c:t result,fOr instanCII,fromdrinking-watermntaminaticn (a.g.lead
pipes),high ambient air c:oncentratians near emission sourceso, rintake via
thefOod dlain.
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