A Small Dose of Metals – 04/13/11 An Introduction To The Health Effects of Metals A Small Dose of ™ Metal ENVIRONMENTAL AND OCCUPATIONAL TOXICOLOGY III

A Small Dose of Metals – 04/13/11

An Introduction To The Health Effects of Metals

A Small Dose of ™ Metal

ENVIRONMENTAL AND OCCUPATIONAL TOXICOLOGY III

(ENVH 516)

A Small Dose of Metals – 04/13/11 A Small Dose of Toxicology

Introduction

Complex relationship to metals –

Nutritionally Important

Toxicologically Important

Medical Important

Chelation


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

Ancient Awareness


80 of 105 elements in the periodic table are labeled as metals

“Mad Hatter” – mercury exposure

Historical Awareness


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


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?)


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

Nutritionally Important

Some metals have very important physiological functions

Cr

Cu

Fe

Mg

Mn

Se

Zn


• 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+

Chromium (Cr)


• Use – essential element, widely used• Source – readily available in food• Recommended daily – 1.5-3.0 mg• Absorption – intestine• Toxicity – deficiency – anemia

- excess rare, Wilson’s disease• Facts – excess treated with penicillamine

- can be toxic grazing animals

Copper (Cu)


• 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

Iron (Fe)


• 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

Magnesium (Mg)


• 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, Parkinson’s -like syndrome, psychiatric disorders

• Facts – half-live 37 days

Manganese (Mn)


• 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

Selenium (Se)


• 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

Zinc (Zn)


Aluminum (Al) Arsenic (As) Cadmium (Cd) Cobalt (Co) Lead (Pb) Mercury – Inorganic (Hg) Mercury – Organic (Hg-CH3)

Nickel (Ni) Tin (Sn)

Toxic Metals

Pb

Co

Al

As

Cd

Hg

Hg-CH3

Ni

Sn


• 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

Aluminum (Al)


• 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…

Arsenic (As)


• 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

Beryllium (Be)


• 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

Cadmium (Cd)


• 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

Cobalt (Co)


• 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

Lead (Pb)


• 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)

Inorganic Mercury (Hg)


• 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)

Organic Mercury (Hg-CH3)


• 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

Nickel (Ni)


• 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

Tin (Sn)


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

Medically Important

A small group of metals are used to treat disease

F

Li

Pt

Ga

Au

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

Bismuth (Bi)


• 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

Fluoride (F)


• 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

Gallium (Ga)


• Use – treat rheumatoid arthritis, range of industrial uses

• Source – mining, medical injection• Absorption – poor• Toxicity – kidney, skin and mouth

lesions• Facts – long half-life

Gold (Au)


• 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

Lithium (Li)


• 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

Platinum (Pt)


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

Chelation


We can not live without metals but some require

our utmost respect.

Summary


A Small Dose of ™ Metal


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.


Authorship Information

For Additional Information ContactSteven G. Gilbert, PhD, DABT

E-mail: [email protected]: www.asmalldoseof.org

This presentation is supplement to “A Small Dose of Toxicology”

Documents

A Small Dose of Metals – 04/13/11 An Introduction To The Health Effects of Metals A Small Dose of ™ Metal ENVIRONMENTAL AND OCCUPATIONAL TOXICOLOGY III