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EFFECT OF LEAD
ON HUMAN
HEALTH
Lead is very useful element which is used in industry and civilization thousands of years ago.
But, it was discovered that Lead can be harmful to human when ingested or inhaled. Lead is
beneficial and cheap so that it will give more earning regardless of impact of health. Because of
that, Some manufacturers are still using it despite of all impacts since no limitation from their
governments. This article aim is to clarify the impacts of Lead on human health and general
applications and uses with testing methods for lead content.
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Effect of Lead on Human Health
Basic Facts of Lead as an Element:
Lead (Pb) has an atomic number of eighty-two. It is a highly malleable member of the metal
elements and is highly resistant to corrosion. Lead has been in use by ancient civilizations for
thousands of years. Also, Lead has a long history in alchemy, since many alchemists believed
lead could be turned into gold. Lead is a fairly weak electrical conductor compared to other
metals. But,
It is very dense and resistant to corrosion, which made it ideal for pipe making. You can find
Lead on Earth in ores of zinc, silver, or copper. Adding trace amounts of other elements can
have significant impact on lead's properties 1.
Effect of Lead on Human Health :
Lead is a naturally-occurring element that can be harmful to humans when ingested or inhaled,
particularly to children under the age of six. Lead poisoning can cause a number of adverse
human health effects, but is particularly detrimental to the neurological development of
children.
Symptoms of Lead Exposure:
Lead poisoning can be a serious public health threat with no unique signs or symptoms. Early
symptoms of lead exposure may include:

persistent fatigue
 irritability
 loss of appetite
 stomach discomfort and/or constipation
 reduced attention span
 insomnia
Failure to treat lead poisoning in the early stages can cause long-term or permanent health
damage, but because of the general nature of symptoms at early stages, lead poisoning is often
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not suspected.
In adults, lead poisoning can cause:

poor muscle coordination
 nerve damage to the sense organs and nerves controlling the body
 increased blood pressure
 hearing and vision impairment
 reproductive problems (e.g., decreased sperm count)
 retarded fetal development even at relatively low exposure levels
In children, lead poisoning can cause:

damage to the brain and nervous system
 behavioral problems
 anemia
 liver and kidney damage
 hearing loss
 hyperactivity
 developmental delays
 in extreme cases, death
Although the effects of lead exposure are a potential concern for all humans, young children
(less than seven years old) are most at risk. This increased vulnerability results from a
combination of the following factors:




Children typically have higher intake rates (per unit body weight) for environmental
media (such as soil, dust, food, water, air, and paint) than adults, since they are more
likely to play in dirt and put their hands and other objects in their mouths;
Children tend to absorb a higher fraction of ingested lead from the gastrointestinal
tract than adults;
Children tend to be more susceptible than adults to the adverse neurological and
developmental effects of lead; and
Nutritional deficiencies of iron or calcium, which are common in children, may
facilitate lead absorption and exacerbate the toxic effects of lead 2.
General Application of Lead :
Lead is a naturally occurring, soft, bluish-gray heavy metal. Although nearly 50% of lead used
today comes from recycled materials such as car batteries, its most common source is the
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mineral Galena (lead sulfide) that forms as pockets or veins in carbonate rock.
Lead has been in use since ancient times. A lead statue discovered in Turkey has been dated to
around 6500 BC. The Romans had indoor plumbing that was made from sheets of lead rolled
into pipe. Plumbum, the Latin word for lead, is also the origin of the word plumber and the
metal’s elemental symbol (Pb). Industrial emissions, combustion of leaded gasoline and
widespread use of lead-based paint have all contributed to a vast amount of air, water and soil
pollution in the 20th Century3.
Lead-Containing Materials
Due to its abundance, low cost and physical properties (low melting point, corrosion resistance,
waterproof nature and malleability) lead and lead compounds have been utilized in a variety of
products including:
Ammunition & fishing sinkers- gasoline-paint & varnish – metal flashing – ceramic glaze , glass
& crystal – tank liners - pipes, faucets & solders- brass, bronze & pewter alloys- caulking &
oakum- pesticides- x-ray shielding- x-ray shielding- batteries,,, ,etc.
What is 'lead paint'?
Any paint that relies on lead compounds for its color. White lead, or lead (II) carbonate
(PbCO3), is a typical example, and was once widely used to paint wooden surfaces in homes.
Other lead compounds, like vivid yellow lead chromate (PbCrO4), were used as coloured
pigments. As well as giving the paint its tint, lead pigments are highly opaque, so that a
relatively small amount of the compound can cover a large area. White lead is very insoluble in
water, making the paint highly water-resistant with a durable, washable finish.
Lead carbonate can also neutralize the acidic decomposition products of some of the oils that
make up the paint, so the coating stays tough, yet flexible and crack-resistant, for longer.
So what's the problem?
Lead is toxic, and as young children tend to chew things, they are particularly prone to
ingesting it. Not good for their vulnerable, developing brains. It was increasingly recognized in
the first half of the 20th century that children were being poisoning with lead paint, and its use
in cots and toys had been phased out in the West by the 1950s. However, lead-based
decorative household paints were still used for another couple of decades before this too
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ended due to health concerns.
Why is lead toxic?
Lead can disrupt numerous crucial bodily functions, and hence has a wide variety of symptoms,
from vomiting to madness to death. It's known to be a potent blocker of receptors of
glutamate, a neurotransmitter crucial for learning. It is also able to displace a series of other
metals from doing their normal job in the body - most significantly, calcium, iron and zinc. A
particular problem is that lead displaces the zinc from the enzyme delta-aminolaevulinate
dehydratase, which is crucial for the biosynthesis of heme, the iron-binding part of the
hemoglobin molecule that carries oxygen around the blood. This results in cells around the
body being short of oxygen, causing a cascade of associated problems4.
Effect of Lead in paint of PPGI
Pre-painted steel, which can be founded in our day to day life, might be harmful to us or our
children. Steel buildings, roofs, walls, school buildings, metal furniture (Hospital cots,
tables/desks in schools), magnetic white boards, refrigerators, and home appliance products
like washing machine, microwave oven and many more are possible places where Lead can
attack human from. Our children come in contact with some or most of these products and we
expect that these products should not have any toxic materials that can affect the health of
children.
Lead in the paint is considered to be toxic and children are most susceptible to exposure as they
have frequent hand to mouth contact, tend to chew things and they are particularly prone to
ingesting it. Not good for their vulnerable, developing brains.
How lead reach to Environment
Dust or chips from lead paint can easily poison children. If children play in areas that contain
lead paint chips or dust, they can get lead dust on their fingers and toys. Since children
frequently put their hands in their mouth and if they have been exposed to lead dust, they will
swallow lead dust. This can cause problems with learning and growth in children ages 6 years
and under. Because they are vulnerable, even small amounts of lead can be harmful.
The most common way for lead to get into soil is from exterior house lead paint. If your home
was built before 1978, it most likely has some lead in the paint. If your home was built before
1950, the paint contains more lead. Lead paint can be a danger to your children if the paint is
chipped, peeling, cracked or chalking; or when repairing or remodeling disturbs it.
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Lead is used as a pigment in paints to get the color, tint and the Opacity. Lead pigments being
highly opaque, relatively small amount of the compound/pigment can cover a large area, thus
making the paint cheaper. This aspect is conveniently used by some of the exporters of Prepainted steel sheets, especially from Far East. They use the cheaper paint containing lead to
make their products competitive at the cost of health, though substitutes for lead based
pigments (Titanium dioxide and zinc oxide) are available.
View of the detrimental effects of lead on health, especially for children, developed countries
have implemented standards to regulate the use of lead in Paint –with more focus on the paint
intended for residential use. Standards between countries vary greatly. , The Global Alliance to
eliminate Lead in Paint (GAELP) agreed on the definition of “Lead Paint” as any paint with a lead
concentration greater than 90ppm.
Effect of Lead in Zinc of GI:
Hot-dip Galvanizing is based on alloying Iron with zinc. Traces of iron introduced into the zinc
kettle(carry-over with the material to be galvanized from wet pre-treatment, from the steel
zinc-kettle-wall and the material to be galvanized will alloy with the zinc too, thus forming zinciron alloy particles called dross. This dross is some heavier than the zinc and will slightly sink to
bottom of the kettle. Lead has two functions: 1. dissolved lead in the zinc-melt has influence on
the fluidity of the zinc and will help dross particles sink to the bottom - floating dross particles
will cause roughness on the material to be galvanized(bad quality) 2. The lead layer on the
bottom of the kettle will prevent dross will be stuck to the iron kettle-bottom and makes it
possible to remove the dross from the bottom of the kettle, because lead is heavier than the
dross and will not alloy with the dross and zinc - so dross floats on the lead-layer.
Galvanizing is the process of coating steel or iron with a layer of zinc.
This layer helps to prevent against the effects of corrosion. The zinc baths used in the coating
Process contains trace amounts of other metals. These metals include lead, aluminum,
chromium, and manganese. When hot work is performed on galvanized metal it creates
hazards for the workers which include dust, gases and fumes5.
Analytical Methods of Lead Content
1) Test the paint for lead in situ using a chemical test kit.
There is a range of chemical test kits, from simple qualitative tests to more sophisticated semi
quantitative tests. Many rely upon a color change to indicate the presence of lead above a
certain concentration. In the simplest kits, the result is either positive (i.e. lead is present above
a certain concentration) or negative (i.e. lead is absent above a certain concentration),
according to whether a color change occurred. The threshold concentration for the colour
change depends upon the test kit used and may be regulated in the country where the test is
marketed. In the USA, for example, test kits should detect concentrations above 0.5% lead by
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weight (5000 mg/kg). Depending on the context in which they are meant to be used, some
chemical test kits may have lower limits of detection.
The simpler kits either test the paint using a swab soaked in a chemical reagent that is rubbed
Onto the painted surface or require the removal of a chip of paint of a specified area that is
then mixed with reagents in a tube. More sophisticated spot test kits use fluorimetric or
photometric methods on paint chips. The United States Environmental Protection Agency
(USEPA) has evaluated a number of these kits, and additional information can be found on its
web site.
Chemical test kits are relatively cheap and do not require specific training, although training of
the user will give more reliable results. The results are immediate. These kits have a number of
limitations, however. The kits can test exposed layers only; therefore, to test underlying layers
that may be more likely to contain lead, it is necessary to score the paint surface or to remove
a chip of paint (depending on the method).
2) Measure the amount of lead in paint in situ using a portable X-ray fluorescence (XRF)
device.
XRF spectrometry is based on the fact that, when exposed to high-energy radiation, lead (like
many other elements) emits X-rays at a characteristic frequency. The intensity of the rays can
be measured and correlated to the amount of lead per unit area (usually in units of milligrams
per square centimeter). As regulatory standards for lead in paint may be expressed in other
units (e.g. parts per million or per cent concentration by weight), the XRF results may need to
be converted. Portable XRF instruments can measure the total amount of lead in a painted
surface in situ without damaging the paint or the substrate.
Legislation on Lead:
This rule establishes standards to help property owners, lead paint professionals and
government agencies identify lead hazards in residential paint, dust and soil. The rule
establishes standards for lead-based paint hazards (including hazards from lead in dust and soil)
in most pre-1978 housing and child-occupied facilities. Under these standards, lead is
considered a hazard when equal to or exceeding 40 micrograms of lead in dust per square foot
on floors, 250 micrograms of lead in dust per square foot on interior window sills, and 400 parts
per million (ppm) of lead in bare soil in children's play areas or 1200 ppm average for bare soil
in the rest of the yard. In addition, paint in deteriorating condition, on a friction or impact
surface, or on certain chewable surfaces is also defined as a hazard.
CONCLUSION:
Finally, lead legislations and regulation should be implemented strictly by governments to stop
greed of some businessmen who don`t care about human health and focusing only on their
earnings. On the other hand, campaigns of awareness of lead effect on health should be
supported by all. Our health is most valuable thing which we should keep in best condition.
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Everybody is responsible to make our planet better place to live on. Our children’s deserve a
better environment condition; at least they will not grantee diseases from childhood.
References:
1 http://www.softschools.com/facts/periodic_table/lead_facts/352/
2 www.epa.gov/superfund/lead/health.htm
3 https://web.stanford.edu/dept/EHS/prod/general/asbestoslead/leadfactsheet.html
4 http://www.rsc.org/chemistryworld/News/2007/August/21080701.asp
5 http://www.finishing.com/245/68.shtml