An Introduction To The Health Effects of Metals

A Small Dose of ™ Metal An Introduction To The Health Effects of Metals A Small Dose of Metal – 3/15/04 Introduction Complex relationship to metals – Nutritionally Important Toxicologically Important Medical Important Chelation A Small Dose of Toxicology A Small Dose of Metal – 3/15/04 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 A Small Dose of Toxicology A Small Dose of Metal – 3/15/04 Historical Awareness  80 of 105 elements in the periodic table are labeled as metals  “Mad Hatter” – mercury exposure A Small Dose of Toxicology A Small Dose of Metal – 3/15/04 Thoughts on Metals  Redistribution • • • • Naturally occurring – break down of rock Human – mining, purify, recombine, use E.g. lead – rise in Greenland ice E.g. inorganic to organic mercury  Changed form  Occupational exposure  Home exposure A Small Dose of Toxicology A Small Dose of Metal – 3/15/04 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?) A Small Dose of Toxicology A Small Dose of Metal – 3/15/04 Nutritionally Important Some metals have very important physiological functions Cr  Chromium (Cr) Cu  Copper (Cu) Fe  Iron (Fe) Mg  Magnesium (Mg) Mn  Manganese (Mn) Se  Selenium (Se) Zn  Zinc (Zn) A Small Dose of Toxicology A Small Dose of Metal – 3/15/04 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+ A Small Dose of Toxicology A Small Dose of Metal – 3/15/04 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, Wilson’s disease • Facts – excess treated with penicillamine - can be toxic grazing animals A Small Dose of Toxicology A Small Dose of Metal – 3/15/04 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 A Small Dose of Toxicology A Small Dose of Metal – 3/15/04 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 A Small Dose of Toxicology A Small Dose of Metal – 3/15/04 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, Parkinson’s like syndrome, psychiatric disorders • Facts – half-live 37 days A Small Dose of Toxicology A Small Dose of Metal – 3/15/04 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 A Small Dose of Toxicology A Small Dose of Metal – 3/15/04 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 A Small Dose of Toxicology A Small Dose of Metal – 3/15/04 Toxic Metals Al As Cd Co Pb Hg Hg-CH3 Ni Sn A Small Dose of Toxicology          Aluminum (Al) Arsenic (As) Cadmium (Cd) Cobalt (Co) Lead (Pb) Mercury – Inorganic (Hg) Mercury – Organic (Hg-CH3) Nickel (Ni) Tin (Sn) A Small Dose of Metal – 3/15/04 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 A Small Dose of Toxicology A Small Dose of Metal – 3/15/04 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… A Small Dose of Toxicology A Small Dose of Metal – 3/15/04 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 A Small Dose of Toxicology A Small Dose of Metal – 3/15/04 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 A Small Dose of Toxicology A Small Dose of Metal – 3/15/04 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 A Small Dose of Toxicology A Small Dose of Metal – 3/15/04 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 A Small Dose of Toxicology A Small Dose of Metal – 3/15/04 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) A Small Dose of Toxicology A Small Dose of Metal – 3/15/04 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) A Small Dose of Toxicology A Small Dose of Metal – 3/15/04 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 A Small Dose of Toxicology A Small Dose of Metal – 3/15/04 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 A Small Dose of Toxicology A Small Dose of Metal – 3/15/04 Medically Important A small group of metals are used to treat disease Bi F Ga Au Li Pt A Small Dose of Toxicology  Bismuth (Bi)  Fluoride (F)  Gallium (Ga)  Gold (Au)  Lithium (Li)  Platinum (Pt) A Small Dose of Metal – 3/15/04 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 A Small Dose of Toxicology A Small Dose of Metal – 3/15/04 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 A Small Dose of Toxicology A Small Dose of Metal – 3/15/04 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 A Small Dose of Toxicology A Small Dose of Metal – 3/15/04 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 A Small Dose of Toxicology A Small Dose of Metal – 3/15/04 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 A Small Dose of Toxicology A Small Dose of Metal – 3/15/04 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 A Small Dose of Toxicology A Small Dose of Metal – 3/15/04 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 A Small Dose of Metal – 3/15/04 A Small Dose of Toxicology Summary We can not live without metals but some require our utmost respect. A Small Dose of Toxicology A Small Dose of Metal – 3/15/04 A Small Dose of ™ Metal A Small Dose of Toxicology A Small Dose of Metal – 3/15/04 Additional Information  Web Sites • • • Health Canada - Nutrition. http://www.hcsc.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. A Small Dose of Toxicology A Small Dose of Metal – 3/15/04 Authorship Information This presentation is supplement to “A Small Dose of Toxicology” For Additional Information Contact Steven G. Gilbert, PhD, DABT E-mail: smdose@asmalldoseof.org Web: www.asmalldoseof.org A Small Dose of Toxicology A Small Dose of Metal – 3/15/04