­ GO 336 Project

Heavy Metals And Their Effect On Our Health and Environment

by

Amy L. Uttinger

http://www.emporia.edu/earthsci/amber/go336/uttinger

This webpage project was created for a Mineralogy course in the fall 2005 semester at Emporia State University.
The assignment was to learn webpage creation as well as present a summary of our knowledge regarding mineralogy.

This image was taken from from www.eeaa.gov.eg/eimp/images/hg_pol.jpg,
and shows pollution by heavy metals (mercury) on the Gulf of Suez;
the image was taken from the website of
The Environmental Information and Monitoring Program

Table of Contents

What are the heavy metals?

Where do they come from?

What are they used for?

How do they effect our health?

How do they effect our environment?

What is being done?

Conclusions

References

Links


What are the heavy metals?

There is more than one definition used to describe the term heavy metals. One such description says they are the chemical elements that have a specific gravity that is five times higher than that of water (Life Extention Foundation, 1995-2005). Another defines heavy metals simply as any metal element that is toxic in nature (Cleaner Production Program, 2005). Still another source indicates heavy metals as approximately 40 electropositive elements naturally occuring in the Earth's crust and having a density greater than 5 (Dartmouth, n.d.). Most of defintions include similar metals or elements so for the purpose of this report, heavy metals shall include: Antimony (Sb - #51), Arsenic (Ar - #18), Mercury (Hg - #80), Lead (Pb - #82), Cadmium (Cd - #48), Molybdnem (Mo - #42) and Zinc (Zn - #30).


Image take from http://www.warwick.surrey.sch.uk/student%20zone/
GCSE%20Science%20Website/periodic_table.htm.

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Where do they come from?

All statistical information below came from the www.mii.org/commonminerals.html, Mineral Information Insitute, unless otherwise indicated.

Element
Mineral Sources
Occurrence
Antimony
Rare element that is not generally found native. Antimony can be found in many different mineral species, but is most commonly extracted from stibnite. For more visit www.mii.org/Minerals/photoant.html Not common in U.S. except in small quantities, but most commonly found in China followed distantly by Russia, South Africa and Bolivia.
Arsenic
 Not common in it's elemental state, but found generally in arsenopyrite. Arsenic can also be extracted to a lesser degree from realgar and enargite. For more visit www.mii.org/Minerals/photoarsenic.html Most common location for occurrence is in France, Germany England and Italy. Not common in U.S. (Chesterman, 2002).
Cadmium
Occurs naturally as an atomic substitution for zinc and zinc minerals. Pure cadmium minerals are rare and greenockite is the best source, but this element is mostly extracted from sphalerite. For more visit www.mii.org/Minerals/photocad.html Germany has been the most important producer.
Lead
The element is rarely found alone naturally, but is mostly extracted from the mineral Galena. for more visit www.mii.org/Minerals/photolead.html In the U.S., Galena is mined in Missouri, Idaho, Alaska and Montana and is also imported from mines in Canada and Mexico.
Mercury
Mercury is a liquid in its elemental state, but in its solid state mercury is found in its primary ore mineral, cinnabar. For more visit www.mii.org/Minerals/photomercury.html Formerly in the U.S. cinnabar was mined from Arkansas, California, Nevada and Oregon. Now major producers include Algeria, Spain and China.
Molybdenum
Molybdenite is the major mineral ore of molybdenum, but it can also be found to a lesser degree in wulfenite. For more visit www.mii.org/Minerals/photomoly.html Colorado, Arizona, New Mexico and Montana are major producers of molybenite, but is also mined in Canada, China Chile and Mexico.
Zinc
Zinc is extracted from various minerals, but the main ore is sphalerite followed by smithsonite and zincite. For more visit www.mii.org/Minerals/photozinc.html The U.S. is a big producer of zinc with Alaska, Tennesse and Missouri as the frontrunners. Outside of the U.S. zinc is mined in Canada, Mexico and Peru.

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What are they used for?

The following information was taken from www.mii.org/commonminerals.html, Mineral Information Insitute, unless otherwise noted.

Element
Element Use
Antimony
Used with plastic, rubber and textiles as a flame retardent. Metal alloy for hardness, alloyed w/tin to make pewter, batteries and in the computer industry as a semiconductor. Also present in some fertilizers. [www.mii.org/commonminerals.html#Ant.]
Arsenic
Used as an alloy, a semiconductor, but largely in the form of chromated copper arseante (CCA) chemical for wood preservation on telephone poles, fense posts and foundation timbers. Also present in some fertilizers. [www.mii.org/Minerals/photoarsenic.html]
Cadmium
Used primarily in the production of nickel-cadmium batteries, but is also used to a smaller degreee as a paint pigment, and in television tubes. Also present in some fertilizers. [www.mii.org/Minerals/photocad.html]
Lead
Used to make car, truck and other vehicle batteries as well as for soldering purposes. Also used in protective x-ray aprons and electronic applications as well as in some fertilizers. [www.mii.org/commonminerals.html#lead]
Mercury
Used to manufacture chlorine as well as an electrical conductor. It is also used in fluorescent lights, thermometers, and as a tooth filler; additionlly it is found in some fertilzers. [www.mii.org/Minerals/photomercury.html]
Molybdenum
Used primarily as an alloy in stainless steels, but used to a lesser degree as a lubricant, catalyst and flame retardent. Also present in some fertilizers. [http://www.mii.org/commonminerals.html#MoS]
Zinc
Used as a galvanizer to prevent iron steel from rusting as well as a metal alloy, and in TV screens. Pennies are also made of zinc that is coated with a thin layer of copper. Also found in some fertilizers. [www.mii.org/commonminerals.html#zn]

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How do they affect our health?

There are many ways in which external materials such as heavy metals can enter the human body and there are far too many sources of exposure to be included in this report. The main focus of the table below is to give a brief summary of the major modes of human intake and the sources from which they derive.

The following information was taken from www.bodyhealth.com/html/metalfree/glossary.asp, BodyHealth.com, and www.nrtco.net/~lead/metals.htm, Lead Environmental Awareness and Detection, unless otherwise indicated.

Metal
Intake Mode
Health Problem
Antimony
Inhalation of airborne particles from smelting or fertilizer production. Also antimony-exposed factory workers absorb the metal via their hair. Liver, kidney and heart damage from elevated exposure.
Arsenic
 Naturally occurring arsenic found in food is the most common source, but contaminated drinking water and soil from smelting or mining operations is a close second. Finally, widespread application of pesticides can also contaminate soil & water. Abdominal pains, hair loss, anemia, skin abnormalities sometimes leading to skin cancer.
Cadmium
 Common contamination sources include inhalation of cigarette and coal burning smoke. Cadmium alloyed water pipes can be a source when water strips the mineral from the pipes and releases into drinking water. Acute toxicity can cause vomiting, and stomach disorders. Chronic exposure can lead to anemia, hypertension, kidney disfunction and bone softening.
Lead
 Ingestion of paint chips from old houses is a common cause of lead poisoning in children. Another source is from drinking water that has been lead contaminated by corrosion of leaded plumbing pipes. Lead can affect the peripheral nervous system causing blindness or hearing loss. It also affects the blood system, heart and kidneys.
Mercury
 The most common source of human exposure to mercury is ingesting fish or seafood containing a form of mercury called methylmercury. Old metal dental fillings is another growing concern. Even though humans can naturally eliminate mercury, it can be toxic at high levels and cause damage to the central nervous system.
Molybdenum
 The toxicity levels of molybdenum in humans is low, however human case studies have been done to assess health affects. High exposure to molybdenum was shown to produce psycosis and irriversable brain damage.
Zinc
 Although zinc is an essential dietary element for humans too much exposure can cause health problems. Toxic levels of zinc can come from contaminated water or soil from fertilizers or mining and can enter they body by ingestion of contaminated water or food (ATSDR, 2004). Can cause acute nausea, stomach cramps or vomiting and over time can cause anemia (ATSDR, 2004).

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How do they affect our environment?

According the the Environmental Protection Agency (EPA) in the United States alone, mining activities including the extraction of metallic ores produce between 1 and 2 billion tons of mine waste annually. More than 130,000 of active and abandoned mines in the U.S. are responsible for polluting over 3,400 miles of streams and over 440,000 acres of land.

These images were taken from: www.umpqua-watersheds.org/local/mine.html and they show polluted drainage in a tributary that is near an abandoned copper and zinc mine.



Cigarette fumes contain harmful chemicals as seen above and second-hand smoke is a large indoor air pollutant.


This image was taken from: tuberose.com/Cigarette_Smoking.html


The most common source of air pollution caused by heavy metals is the emission of smeltering fumes. Lead automobile fuel used to be a leading cause of lead released in the atmoshphere, but its removal from most fuels has greatly reduced this problem. Unfortunately leaded gas is still used for small planes and race cars as well as in lead-acid car batteries. Right now, at least 70% of lead pollution comes from smelters, power plants fueled by coal, and lead used in the processing of oil shale (Delphi International, 2003).



The image to the left was taken from: www.creativepro.com/story/feature/20887.html?origin=story. It is a drawing of the Manning, Bowman Company in Meriden Connecticut, which made cocktail shakers, small appliances and other metal items



Primary sources for heavy metal soil contamination include:
  • Fertilizers containing cadmium, lead and arsenic
  • Pesticides containing lead arsenic and mercury
  • Sewage sludge containing cadmium, arseninc and lead (Odum, 2000)
  • Irrigation water may transport dissolved heavy metals to agricultural fields where metals such as cadmium may be incorporated into plant tissue.(NCSU Water Quality Group, 1976)



    The image to the right was taken from: www.lehman.cuny.edu/deannss/geography/heavy_metals_cover.htm and it is actually part of a student project studying the identification of heavy metals in the Bronx River Watershed in New York.

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    What is being done?

    The Environmental Protection Agency has developed policies to help defend the environment and subsequently our health against harmful toxins such as some heavy metals. The Clean Air Act states in Sec. 211 (k) part D that gasoline shall have no heavy metals, including lead or manganese to prevent toxic air pollutant emissions from motor vehicles. This same act also addresses the improvements and prevention of air pollution through stationary sources such as power plants, gas stations, homes and incinerators. In Section 103 the act requires such facilities to utilize strategies and technologies to imporve and reduce air pollution. Legal actions such as fines and jail terms are enforced to make sure the act is followed (EPA, n.d.).

    Many states have adopted laws prohibiting smoking in public places, in fact all 50 states as well as the District of Columbia have clean indoor air provisions restricting smoking in certain places (American Cancer Society, 2005). Examples of specifics include: Prohibition of smoking in all private workplaces, restaurants and bars - enforced by Delaware, New York, Massachusetts, Rhode Island, Maine, Vermont, Florida, North Dakota, South Dakota, Idaho and Utah (American Cancer Society, 2005).

    The EPA Clean Water Act provides laws to prevent water pollution from sewer and sanitary overflows as well as poor mining practices and urban and rural sprawl (EPA, nd). Also, there are actually several organizations on the state and federal level working hard to prevent water, air and soil pollution utlizing many procedures; however, this report will discuss in detail two different uses for removing heavy metals in water and soil.

    Both of the above mentioned methods are currently being utilized to remove harmful heavy metals from our environment.

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    Conclusions

    Heavy metals occur naturally in the Earth however, overuse and overmining of them can cause serious harm to our health and our environment. It's interesting that these naturally occurring elements have been put to use in so many ways that without them, our lives would not be the same, yet this usage has also put our lives in danger.

    The use of heavy metals in various forms will continue as it has begun however, there is growing concern for the preservation of our health and environment. New methods of for old ecosysems such as wetlands being constructed to remove metals may imporove the threat of heavy metal toxins in the environment.

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    References and Links

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    Return to the GO336 Mineralogy student webpage index, www.emporia.edu/earthsci/amber/go336/webpages.htm.

    Date of creation, November 28, 2005. © Amy Uttinger 2005. Comments may be directed to at: auttinger@cablerocket.com