 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
NCP Miracle II
161 Richardson-Bass Rd
Kenly, NC 27542
Tel:(919)284-6002 Fax:(919)284-4197
EMail: info1@ncpmiracle2.com
161 Richardson-Bass Rd
Kenly, NC 27542
Tel:(919)284-6002 Fax:(919)284-4197
EMail: info1@ncpmiracle2.com
| Heavy Metals |
The term heavy metal refers to any metallic chemical element that has a
relatively high density and is toxic or poisonous at low concentrations.
Examples of heavy metals include mercury (Hg), cadmium (Cd), arsenic
(As), chromium (Cr), thallium (Tl), and lead (Pb).
Heavy 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 elements, some heavy metals (e.g. copper,
selenium, zinc) are essential to maintain the metabolism of the human
body. However, at higher concentrations they can lead to poisoning. Heavy
metal poisoning could result, for instance, from drinking-water
contamination (e.g. lead pipes), high ambient air concentrations near
emission sources, or intake via the food chain.
Heavy metals are dangerous because they tend to bio-accumulate.
Bioaccumulation means an increase in the concentration of a chemical in a
biological organism over time, compared to the chemical's concentration
in the environment. Compounds accumulate in living things any time they
are taken up and stored faster than they are broken down (metabolized) or
excreted.
Heavy metals can enter a water supply by industrial and consumer waste,
or even from acidic rain breaking down soils and releasing heavy metals
into streams, lakes, rivers, and groundwater.
Environmental and health risks
Now we are going to describe the effects of the heavy metals in the
environment. The three most pollutant heavy metals are Lead, Cadmium,
and Mercury.
Effects of Antimony on the environment
Antimony is a metal used in the compound antimony trioxide, a flame
retardant. It can also be found in batteries, pigments, and ceramics and
glass. Exposure to high levels of antimony for short periods of time
causes nausea, vomiting, and diarrhea. There is little information on the
effects of long-term antimony exposure, but it is a suspected human
carcinogen. Most antimony compounds do not bio-accumulate in aquatic
life.
Effects of Cadmium on the environment
Cadmium derives its toxicological properties from its chemical similarity to
zinc an essential micronutrient for plants, animals and humans. Cadmium is
bio-persistent and, once absorbed by an organism, remains resident for
many years (over decades for humans) although it is eventually excreted.
In humans, long-term exposure is associated with renal disfunction. High
exposure can lead to obstructive lung disease and has been linked to lung
cancer, although data concerning the latter are difficult to interpret due to
compounding factors. Cadmium may also produce bone defects
(osteomalacia, osteoporosis) in humans and animals. In addition, the metal
can be linked to increased blood pressure and effects on the myocardium
in animals, although most human data do not support these findings.
The average daily intake for humans is estimated as 0.15µg from air and
1µg from water. Smoking a packet of 20 cigarettes can lead to the
inhalation of around 2-4µg of cadmium, but levels may vary widely.
In what form is emitted Cadmium?
Cadmium is produced as an inevitable by-product of zinc (or occasionally
lead) refining, since these metals occur naturally within the raw ore.
However, once collected the cadmium is relatively easy to recycle.
The most significant use of cadmium is in nickel/cadmium batteries, as
rechargeable or secondary power sources exhibiting high output, long
life, low maintenance and high tolerance to physical and electrical stress.
Cadmium coatings provide good corrosion resistance, particularly in high
stress environments such as marine and aerospace applications where
high safety or reliability is required; the coating is preferentially corroded
if damaged. Other uses of cadmium are as pigments, stabilizers for PVC, in
alloys and electronic compounds. Cadmium is also present as an impurity
in several products, including phosphate fertilizers, detergents and
refined petroleum products.
In the general, non-smoking population the major exposure pathway is
through food, via the addition of cadmium to agricultural soil from various
sources (atmospheric deposition and fertilizer application) and uptake by
food and fodder crops. Additional exposure to humans arises through
cadmium in ambient air and drinking water.
Effects of Chromium on the environment
Chromium is used in metal alloys and pigments for paints, cement, paper,
rubber, and other materials. Low-level exposure can irritate the skin and
cause ulceration. Long-term exposure can cause kidney and liver damage,
and damage too circulatory and nerve tissue. Chromium often
accumulates in aquatic life, adding to the danger of eating fish that may
have been exposed to high levels of chromium.
Effects of Copper on the environment
Copper is an essential substance to human life, but in high doses it can
cause anemia, liver and kidney damage, and stomach and intestinal
irritation. People with Wilson's disease are at greater risk for health effects
from overexposure to copper. Copper normally occurs in drinking water
from copper pipes, as well as from additives designed to control algal
growth.
Effects of Lead on the environment
In humans exposure to lead can result in a wide range of biological effects
depending on the level and duration of exposure. Various effects occur
over a broad range of doses, with the developing foetus and infant being
more sensitive than the adult. High levels of exposure may result in toxic
biochemical effects in humans which in turn cause problems in the
synthesis of hemoglobin, effects on the kidneys, gastrointestinal tract,
joints and reproductive system, and acute or chronic damage to the
nervous system.
Lead poisoning, which is so severe as to cause evident illness, is now
very rare indeed. At intermediate concentrations, however, there is
persuasive evidence that lead can have small, subtle, sub-clinical effects,
particularly on neuropsychological developments in children. Some
studies suggest that there may be a loss of up to 2 IQ points for a rise in
blood lead-levels from 10 to 20µg/dl in young children.
Average daily lead intake for adults in the UK is estimated at 1.6µg from air,
20µg from drinking water and 28µg from food. Although most people
receive the bulk of their lead intake from food, in specific populations
other sources may be more important, such as water in areas with lead
piping and plumbosolvent water, air near point of source emissions, soil,
dust, paint flakes in old houses or contaminated land. Lead in the air
contributes to lead levels in food through deposition of dust and rain
containing the metal, on crops and the soil. For the majority of people in
the UK, however, dietary lead exposure is well below the provisional
tolerable weekly intake recommended by the UN Food and Agriculture
Organization and the World Health Organization.
In what form is emitted lead?
Lead in the environment arises from both natural and anthropogenic
sources. Exposure can occur through drinking water, food, air, soil and
dust from old paint containing lead. In the general non-smoking, adult
population the major exposure pathway is from food and water. Food, air,
water and dust/soil are the major potential exposure pathways for infants
and young children. For infants up to 4 or 5 months of age, air, milk
formulae and water are the significant sources.
Lead is among the most recycled non-ferrous metals and its secondary
production has therefore grown steadily in spite of declining lead prices.
Its physical and chemical properties are applied in the manufacturing,
construction and chemical industries. It is easily shaped and is malleable
and ductile. There are eight broad categories of use: batteries, petrol
additives (no longer allowed in the EU), rolled and extruded products,
alloys, pigments and compounds, cable sheathing, shot and ammunition.
Effects of Mercury on the environment
Mercury is a toxic substance which has no known function in human
biochemistry or physiology and does not occur naturally in living
organisms. Inorganic mercury poisoning is associated with tremors,
gingivitis and/or minor psychological changes, together with spontaneous
abortion and congenital malformation.
Monomethylmercury causes damage to the brain and the central nervous
system, while foetal and postnatal exposure have given rise to abortion,
congenital malformation and development changes in young children.
In what form is emitted Mercury?
Mercury is a global pollutant with complex and unusual chemical and
physical properties. The major natural source of mercury is the degassing
of the Earth’s crust, emissions from volcanoes and evaporation from
natural bodies of water.
World-wide mining of the metal leads to indirect discharges into the
atmosphere. The usage of mercury is widespread in industrial processes
and in various products (e.g. batteries, lamps and thermometers). It is also
widely used in dentistry as an amalgam for fillings and by the
pharmaceutical industry. Concern over mercury in the environment arises
from the extremely toxic forms in which mercury can occur.
Mercury is mostly present in the atmosphere in a relatively unreactive
form as a gaseous element. The long atmospheric lifetime (of the order of
1 year) of its gaseous form means the emission, transport and deposition
of mercury is a global issue.
Natural biological processes can cause methylated forms of mercury to
form which bio-accumulate over a million-fold and concentrate in living
organisms, especially fish. These forms of mercury: monomethylmercury
and dimethylmercury are highly toxic, causing neurotoxicological
disorders. The main pathway for mercury to humans is through the food
chain and not by inhalation.
The main sources of mercury emissions in the UK are from the
manufacture of chlorine in mercury cells, non-ferrous metal production,
coal combustion and crematoria. UK emissions of mercury are uncertain
and it is estimated that the range is from 13 to 36 tons per year (DERA).
Emissions are estimated to have declined by around ¾’s between, 1970-
1998 (NAEI), mainly due to improved controls on mercury cells and their
replacement, and the fall in coal use.
Whilst there has been a decline in the level of European emissions of
mercury, emissions from outside of Europe have started to increase –
increasing the level of ambient concentrations in the continent.
Effects of Nickel on the environment
Small amounts of Nickel are needed by the human body to produce red
blood cells, however, in excessive amounts, can become mildly toxic.
Short-term overexposure to nickel is not known to cause any health
problems, but long-term exposure can cause decreased body weight,
heart and liver damage, and skin irritation. The EPA does not currently
regulate nickel levels in drinking water. Nickel can accumulate in aquatic
life, but its presence is not magnified along food chains.
Effects of Selenium on the environment
Selenium is needed by humans and other animals in small amounts, but in
larger amounts can cause damage to the nervous system, fatigue, and
irritability. Selenium accumulates in living tissue, causing high selenium
content in fish and other organisms, and causing greater health problems
in human over a lifetime of overexposure. These health problems include
hair and fingernail loss, damage to kidney and liver tissue, damage to
circulatory tissue, and more severe damage to the nervous system.
relatively high density and is toxic or poisonous at low concentrations.
Examples of heavy metals include mercury (Hg), cadmium (Cd), arsenic
(As), chromium (Cr), thallium (Tl), and lead (Pb).
Heavy 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 elements, some heavy metals (e.g. copper,
selenium, zinc) are essential to maintain the metabolism of the human
body. However, at higher concentrations they can lead to poisoning. Heavy
metal poisoning could result, for instance, from drinking-water
contamination (e.g. lead pipes), high ambient air concentrations near
emission sources, or intake via the food chain.
Heavy metals are dangerous because they tend to bio-accumulate.
Bioaccumulation means an increase in the concentration of a chemical in a
biological organism over time, compared to the chemical's concentration
in the environment. Compounds accumulate in living things any time they
are taken up and stored faster than they are broken down (metabolized) or
excreted.
Heavy metals can enter a water supply by industrial and consumer waste,
or even from acidic rain breaking down soils and releasing heavy metals
into streams, lakes, rivers, and groundwater.
Environmental and health risks
Now we are going to describe the effects of the heavy metals in the
environment. The three most pollutant heavy metals are Lead, Cadmium,
and Mercury.
Effects of Antimony on the environment
Antimony is a metal used in the compound antimony trioxide, a flame
retardant. It can also be found in batteries, pigments, and ceramics and
glass. Exposure to high levels of antimony for short periods of time
causes nausea, vomiting, and diarrhea. There is little information on the
effects of long-term antimony exposure, but it is a suspected human
carcinogen. Most antimony compounds do not bio-accumulate in aquatic
life.
Effects of Cadmium on the environment
Cadmium derives its toxicological properties from its chemical similarity to
zinc an essential micronutrient for plants, animals and humans. Cadmium is
bio-persistent and, once absorbed by an organism, remains resident for
many years (over decades for humans) although it is eventually excreted.
In humans, long-term exposure is associated with renal disfunction. High
exposure can lead to obstructive lung disease and has been linked to lung
cancer, although data concerning the latter are difficult to interpret due to
compounding factors. Cadmium may also produce bone defects
(osteomalacia, osteoporosis) in humans and animals. In addition, the metal
can be linked to increased blood pressure and effects on the myocardium
in animals, although most human data do not support these findings.
The average daily intake for humans is estimated as 0.15µg from air and
1µg from water. Smoking a packet of 20 cigarettes can lead to the
inhalation of around 2-4µg of cadmium, but levels may vary widely.
In what form is emitted Cadmium?
Cadmium is produced as an inevitable by-product of zinc (or occasionally
lead) refining, since these metals occur naturally within the raw ore.
However, once collected the cadmium is relatively easy to recycle.
The most significant use of cadmium is in nickel/cadmium batteries, as
rechargeable or secondary power sources exhibiting high output, long
life, low maintenance and high tolerance to physical and electrical stress.
Cadmium coatings provide good corrosion resistance, particularly in high
stress environments such as marine and aerospace applications where
high safety or reliability is required; the coating is preferentially corroded
if damaged. Other uses of cadmium are as pigments, stabilizers for PVC, in
alloys and electronic compounds. Cadmium is also present as an impurity
in several products, including phosphate fertilizers, detergents and
refined petroleum products.
In the general, non-smoking population the major exposure pathway is
through food, via the addition of cadmium to agricultural soil from various
sources (atmospheric deposition and fertilizer application) and uptake by
food and fodder crops. Additional exposure to humans arises through
cadmium in ambient air and drinking water.
Effects of Chromium on the environment
Chromium is used in metal alloys and pigments for paints, cement, paper,
rubber, and other materials. Low-level exposure can irritate the skin and
cause ulceration. Long-term exposure can cause kidney and liver damage,
and damage too circulatory and nerve tissue. Chromium often
accumulates in aquatic life, adding to the danger of eating fish that may
have been exposed to high levels of chromium.
Effects of Copper on the environment
Copper is an essential substance to human life, but in high doses it can
cause anemia, liver and kidney damage, and stomach and intestinal
irritation. People with Wilson's disease are at greater risk for health effects
from overexposure to copper. Copper normally occurs in drinking water
from copper pipes, as well as from additives designed to control algal
growth.
Effects of Lead on the environment
In humans exposure to lead can result in a wide range of biological effects
depending on the level and duration of exposure. Various effects occur
over a broad range of doses, with the developing foetus and infant being
more sensitive than the adult. High levels of exposure may result in toxic
biochemical effects in humans which in turn cause problems in the
synthesis of hemoglobin, effects on the kidneys, gastrointestinal tract,
joints and reproductive system, and acute or chronic damage to the
nervous system.
Lead poisoning, which is so severe as to cause evident illness, is now
very rare indeed. At intermediate concentrations, however, there is
persuasive evidence that lead can have small, subtle, sub-clinical effects,
particularly on neuropsychological developments in children. Some
studies suggest that there may be a loss of up to 2 IQ points for a rise in
blood lead-levels from 10 to 20µg/dl in young children.
Average daily lead intake for adults in the UK is estimated at 1.6µg from air,
20µg from drinking water and 28µg from food. Although most people
receive the bulk of their lead intake from food, in specific populations
other sources may be more important, such as water in areas with lead
piping and plumbosolvent water, air near point of source emissions, soil,
dust, paint flakes in old houses or contaminated land. Lead in the air
contributes to lead levels in food through deposition of dust and rain
containing the metal, on crops and the soil. For the majority of people in
the UK, however, dietary lead exposure is well below the provisional
tolerable weekly intake recommended by the UN Food and Agriculture
Organization and the World Health Organization.
In what form is emitted lead?
Lead in the environment arises from both natural and anthropogenic
sources. Exposure can occur through drinking water, food, air, soil and
dust from old paint containing lead. In the general non-smoking, adult
population the major exposure pathway is from food and water. Food, air,
water and dust/soil are the major potential exposure pathways for infants
and young children. For infants up to 4 or 5 months of age, air, milk
formulae and water are the significant sources.
Lead is among the most recycled non-ferrous metals and its secondary
production has therefore grown steadily in spite of declining lead prices.
Its physical and chemical properties are applied in the manufacturing,
construction and chemical industries. It is easily shaped and is malleable
and ductile. There are eight broad categories of use: batteries, petrol
additives (no longer allowed in the EU), rolled and extruded products,
alloys, pigments and compounds, cable sheathing, shot and ammunition.
Effects of Mercury on the environment
Mercury is a toxic substance which has no known function in human
biochemistry or physiology and does not occur naturally in living
organisms. Inorganic mercury poisoning is associated with tremors,
gingivitis and/or minor psychological changes, together with spontaneous
abortion and congenital malformation.
Monomethylmercury causes damage to the brain and the central nervous
system, while foetal and postnatal exposure have given rise to abortion,
congenital malformation and development changes in young children.
In what form is emitted Mercury?
Mercury is a global pollutant with complex and unusual chemical and
physical properties. The major natural source of mercury is the degassing
of the Earth’s crust, emissions from volcanoes and evaporation from
natural bodies of water.
World-wide mining of the metal leads to indirect discharges into the
atmosphere. The usage of mercury is widespread in industrial processes
and in various products (e.g. batteries, lamps and thermometers). It is also
widely used in dentistry as an amalgam for fillings and by the
pharmaceutical industry. Concern over mercury in the environment arises
from the extremely toxic forms in which mercury can occur.
Mercury is mostly present in the atmosphere in a relatively unreactive
form as a gaseous element. The long atmospheric lifetime (of the order of
1 year) of its gaseous form means the emission, transport and deposition
of mercury is a global issue.
Natural biological processes can cause methylated forms of mercury to
form which bio-accumulate over a million-fold and concentrate in living
organisms, especially fish. These forms of mercury: monomethylmercury
and dimethylmercury are highly toxic, causing neurotoxicological
disorders. The main pathway for mercury to humans is through the food
chain and not by inhalation.
The main sources of mercury emissions in the UK are from the
manufacture of chlorine in mercury cells, non-ferrous metal production,
coal combustion and crematoria. UK emissions of mercury are uncertain
and it is estimated that the range is from 13 to 36 tons per year (DERA).
Emissions are estimated to have declined by around ¾’s between, 1970-
1998 (NAEI), mainly due to improved controls on mercury cells and their
replacement, and the fall in coal use.
Whilst there has been a decline in the level of European emissions of
mercury, emissions from outside of Europe have started to increase –
increasing the level of ambient concentrations in the continent.
Effects of Nickel on the environment
Small amounts of Nickel are needed by the human body to produce red
blood cells, however, in excessive amounts, can become mildly toxic.
Short-term overexposure to nickel is not known to cause any health
problems, but long-term exposure can cause decreased body weight,
heart and liver damage, and skin irritation. The EPA does not currently
regulate nickel levels in drinking water. Nickel can accumulate in aquatic
life, but its presence is not magnified along food chains.
Effects of Selenium on the environment
Selenium is needed by humans and other animals in small amounts, but in
larger amounts can cause damage to the nervous system, fatigue, and
irritability. Selenium accumulates in living tissue, causing high selenium
content in fish and other organisms, and causing greater health problems
in human over a lifetime of overexposure. These health problems include
hair and fingernail loss, damage to kidney and liver tissue, damage to
circulatory tissue, and more severe damage to the nervous system.