An Introduction To The Health Effects of Metals

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An Introduction To The Health Effects of Metals
A Small Dose of Metal
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Introduction

• Complex relationship to metals
• Nutritionally Important
• Toxicologically Important
• Medical Important
• Chelation

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Ancient Awareness

• Lead - usage began 4000 years ago
• Hippocreates 370 BC noted abdominal colic in
  miner
• Arsenic therapeutic and a poison (400 BC)
• Lead makes the mind give way. The Greek
  Dioscerides 2nd century BC

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Historical Awareness

• 80 of 105 elements in the periodic table are
  labeled as metals
• Mad Hatter mercury exposure

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Thoughts on Metals

• Redistribution
• Naturally occurring break down of rock
• Human mining, purify, recombine, use
• E.g. lead rise in Greenland ice
• Changed form
• E.g. inorganic to organic mercury
• Occupational exposure
• Home exposure

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Susceptibility to Metals

• Age young or old?
• Nutrition (competion with essential metals)
• Allergic response (immune system)
• Form of metal (organic or inorganic)
• Lifestyle smoking or alcohol
• Occupation
• Home environment (lead paint?)

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Nutritionally Important
Some metals have very important physiological
functions

• Chromium (Cr)
• Copper (Cu)
• Iron (Fe)
• Magnesium (Mg)
• Manganese (Mn)
• Selenium (Se)
• Zinc (Zn)

Cr
Cu
Fe
Mg
Mn
Se
Zn
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Chromium (Cr)

• Use essential element, associated with insulin,
  stainless steel, tanning leather
• Source food supply, inhalation
• Recommended daily 50-200 µg
• Absorption intestine
• Toxicity acute exposure cause kidney damage,
  lung cancer
• Facts comes in different oxidized forms
  Cr3, Cr6

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Copper (Cu)

• Use essential element, widely used
• Source readily available in food
• Recommended daily 1.5-3.0 mg
• Absorption intestine
• Toxicity deficiency anemia
• - excess rare, Wilsons disease
• Facts excess treated with penicillamine
• - can be toxic grazing animals

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Iron (Fe)

• Use oxygen carrying hemoglobin
• Source food
• Recommended daily 10-15 mg
• Absorption intestine
• Toxicity excess causes bloody fesses, bloody
  vomit, liver damage
• Facts - 3-5 grams in the body
• 67 associated with hemoglobin

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Magnesium (Mg)

• Use essential nutrient, associated with many
  enzymes, antacids
• Recommended daily 280-350 mg
• Source food supply, nuts, cereals, seafood,
  meats, drinking water
• Absorption small intestine
• Toxicity deficiency convulsions
• - excess nervous system
• Facts 20 grams in body

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Manganese (Mn)

• Use trace element, associated with many enzymes
• Source food supply, grains, nuts
• Recommended daily 2 to 5 mg
• Absorption intestine poor (5)
• Toxicity inhalation respiratory disease,
  nervous system, Parkinsons -like syndrome,
  psychiatric disorders
• Facts half-live 37 days

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Selenium (Se)

• Use essential element, present in most tissue,
  anticancer, reduces toxicity of metal mercury and
  cadmium
• Source food supply, shrimp, meat
• Recommended daily 55-70 µg/day, not to exceed
  200 µg/day
• Absorption intestine
• Toxicity deficiency heart disorders
• - excess blind staggers, neurological effects

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Zinc (Zn)

• Use essential element, cofactor with several
  enzymes, and proteins
• Source food supply, drinking water
• Recommended daily 12-25 mg
• Absorption intestine
• Toxicity deficiency impaired growth,
  neurological disorders, - inhalation can cause
  metal fume fever

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Toxic Metals

• Aluminum (Al)
• Arsenic (As)
• Cadmium (Cd)
• Cobalt (Co)
• Lead (Pb)
• Mercury Inorganic (Hg)
• Mercury Organic (Hg-CH3)
• Nickel (Ni)
• Tin (Sn)

Al
As
Cd
Co
Pb
Hg
Hg-CH3
Ni
Sn
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Aluminum (Al)

• Use wide range of consumer products, airplanes
  to cans
• Source food, drinking water
• Absorption poor
• Toxicity Dialysis dementia, possibly neurotoxic
• Facts non-essential, intake 1-10 mg/day

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Arsenic (As)

• Use pesticide and herbicide
• Source food, drinking water
• Absorption intestine
• Toxicity cancer, heart, liver, neurological
• Facts exists in different states trivalent
  (most common), pentavalent, arsenic trioxide,
  organic and inorganic ...etc

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Beryllium (Be)

• Use metal alloy, nuclear power plants
• Source workplace, coal combustion
• Absorption lung, skin
• Toxicity lung, can be delayed and is
  progressive, contact dermatitis probable
  carcinogen
• Facts discovered in 1828, more that 1250 tons
  from oil and coal combustion

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Cadmium (Cd)

• Use alloy in metal, paint
• Source shellfish, cigarette smoke, workplace
  welding, paints
• Absorption intestine, lungs
• Toxicity lung, emphysema, kidney, calcium
  metabolism, possible lung carcinogen
• Facts Itai-Itai is Japanese for ouch-ouch
  refers to bone pain related to calcium loss

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Cobalt (Co)

• Use component of vitamin B12,
• Source alloy in metals, magnets
• Recommended daily none
• Absorption intestine
• Toxicity excessive heart failure, inhalation
  hard metal lung disease
• Facts once used a foaming agent in beer

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Lead (Pb)

• Use not essential, batteries, old paint and
  previously gasoline, hobbies
• Source home, paint, dust, kids-hands to mouth,
  workplace
• Absorption intestine (50 kids, 10 adults)
• Toxicity developmental and nervous system
• Facts developing nervous system very sensitive
  to low levels of exposure

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Inorganic Mercury (Hg)

• Use consumer products, industry, dental
  amalgams, switches, thermometers
• Source mining, environment
• Absorption inhalation, intestine poor
• Toxicity nervous system toxicant, Mad Hatters
  disease
• Facts liquid silver evaporates at room
  temperature, bacteria convert to organic methyl
  mercury (see next slide)

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Organic Mercury (Hg-CH3)

• Use limited laboratory use - most common is
  methyl mercury (Hg-CH3)
• Source contaminates some fish (e.g. tuna,
  shark, pike)
• Absorption intestine very good (90)
• Toxicity nervous system toxicant, and
  developmental toxicant
• Facts bacteria convert inorganic mercury to
  methyl mercury then in to food supply
  (bioaccumulation)

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Nickel (Ni)

• Use not essential, metal alloy, stainless steel
• Source food supply, jewelry, workplace
• Absorption intestine, skin
• Toxicity carcinogen (lung), contact dermatitis
• Facts discovered in 1751, 200,000 metric tons
  used yearly

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Tin (Sn)

• Use inorganic consumer products
• - organic fungicide, bactericides
• Source food packaging
• Absorption intestine (low inorganic, high
  organic)
• Toxicity inorganic - little
• - organic central nervous system
• Facts triethyltin and trimethyltin most toxic

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Medically Important
A small group of metals are used to treat disease

• Bismuth (Bi)
• Fluoride (F)
• Gallium (Ga)
• Gold (Au)
• Lithium (Li)
• Platinum (Pt)

Bi
F
Ga
Au
Li
Pt
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Bismuth (Bi)

• Use antacids, diarrhea
• Source mining, consumer products
• Absorption intestine
• Toxicity kidney, chronic use results in range
  of effects
• Facts discovered in 1753, used to treat
  syphilis and malaria

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Fluoride (F)

• Use tooth protection
• Source drinking water, food supply
• Absorption intestine
• Toxicity excess causes mottled teeth enamel
  (fluorosis)
• Facts common water level 0.5 to 1.5 ppm, 3 ppm
  effects teeth

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Gallium (Ga)

• Use visualization tool for soft tissues in
  x-rays
• Source mining, medical injection
• Absorption very poor
• Toxicity kidney
• Facts liquid at room temperature, half-life 4
  to 5 days

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Gold (Au)

• Use treat rheumatoid arthritis, range of
  industrial uses
• Source mining, medical injection
• Absorption poor
• Toxicity kidney, skin and mouth lesions
• Facts long half-life

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Lithium (Li)

• Use treat psychiatric disorders
• Source food supply, plants meat
• Absorption intestine
• Toxicity wide range, e.g. tremor, seizures,
  slurred speech, cardiovascular, nausea, vomiting
• Facts daily intake about 2 mg

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Platinum (Pt)

• Use anti-cancer agent (cisplatin), catalytic
  converters, metal alloy
• Source mining, road dust
• Absorption poor, as a drug intravenous
  administration
• Toxicity neuromuscular, kidney
• Facts inhibits cell division, treat ovarian
  testicular cancer

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Chelation

• Properties
• Metal chelators accelerate the excretion of metal
  from the body
• Non-specific can remove essential metals and
  elements
• Chelate is from the Geek word for claw
• Examples
• BAL one of the first, broad action but
  potentially toxic
• Calcium EDTA lead
• Penicillamine copper
• Desferrioxamine iron
• DMPS lead, mercury
• Number of others

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Summary
We can not live without metals but some require
our utmost respect.
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A Small Dose of Metal
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Additional Information

• Web Sites
• Health Canada - Nutrition. http//www.hc-sc.gc.ca/
  english/lifestyles/food_nutr.html
• U.S. Agency for Toxic Substance Disease Registry
  (ATSDR). http//www.atsdr.cdc.gov/
• Dartmouth Toxic Metals Research Program.
  http//www.dartmouth.edu/toxmetal/HM.shtml The
  site has general information on toxic metals.

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Authorship Information
This presentation is supplement to A Small
Dose of Toxicology
For Additional Information Contact Steven G.
Gilbert, PhD, DABT E-mail smdose_at_asmalldoseof.org
Web www.asmalldoseof.org