heavy metals & their effects

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.

It mainly includes the transition metals, some metalloids, lanthanides, and actinides. Many different definitions have been proposed—some based on density, some on atomic number or atomic weight, and some on chemical properties or toxicity.

Examples:

Examples of heavy metals include lead, mercury, cadmium, sometimes chromium. Less commonly, metals including iron, copper, zinc, aluminum, beryllium, cobalt, manganese and arsenic may be considered heavy metals.

EFFECTS N PRESENCE

Heavy metals with adverse health effects in human metabolism (including lead, cadmium, and mercury) present obvious concerns due to their persistence in the environment. Acute heavy metal intoxications may damage central nervous function, the cardiovascular and gastrointestinal (GI) systems, lungs, kidneys, liver, endocrine glands, and bones. Chronic heavy metal exposure has been implicated in several degenerative diseases of these same systems and may increase the risk of some cancers

Cadmium:

• Found in: mostly cigarettes, cadmium is also concentrated in the water, air, and soil especially in industrial areas where smelting and refining occurs – thus, it can be found in the food supply in those regions.  It is also used in the manufacture of batteries or plastics.
• Concentrates in: kidneys, liver, and pancreas, but easily absorbed through the lungs.
• What it Causes: carcinogenic (causes cancer), and can lead to kidney failure, gout, and loss of sense of smell.

Lead:

• Found in: Exposure can frequently be geographical or occupational (living near or working in a lead smelter or lead mine, welding, construction, and manufacture of certain products such as glass, vinyl mini-blinds, ceramic glaze).  It can also be found in paint (back when it was made with lead), old pipes leading to a contaminated water supply, some herbal remedies imported from overseas, and many others.
• Concentrates in: the bones. When bone begins to break down at an older age, or after menopause for women, symptoms can arise or worsen.
• What It Causes: In children, lead has been linked with learning and developmental disabilities including lower IQ, and ADD.  In general it is associated with other neurological problems such as depression and anxiety, Alzheimer’s, and Parkinson’s Disease.  It can also cause high blood pressure, often poorly or unresponsive to medication.

Mercury:

• Found in: farmed or Atlantic fish, and also in dental amalgams.  (If you have a mouth full of mercury fillings, you can let off enough mercury vapor every time you chew that your mouth will exceed OSHA standards for acceptable levels!)  Mercury used to be used as a preservative in vaccines (called thimerosol), but thimerosol has been eliminated from most vaccines now except for the influenza vaccine.  (It is possible to get flu vaccines without thimerosol, though.)
• Concentrates in: the nervous system
• What It Causes: Mercury eats up your body’s antioxidant reserves, leaving you vulnerable to oxidative damage.  This is probably why it has been linked to an increased risk of cardiovascular disease.  It also inhibits your body’s ability to make ATP (the energy currency of the body).  For more on associated conditions and symptoms, see here.  (There’s a lot.)

Aluminum:

• Found in: pans for cooking, “tin” foil, aluminum-based antiperspirants, antacids and many other over-the-counter medications, and in processed foods using baking powder (not baking soda – these are different) and self-rising flour (those that don’t include yeast).  Examples include processed cheese and cheese products, cake mixes, pancake mixes, rising flours, and frozen dough.  Aluminum has also replaced mercury in most vaccines as a preservative.
• Concentrates in: the lungs, bones, and nervous system.
• What it Causes: There is some evidence that Aluminum may be correlated with the rise in autism.  (Disclaimer: I am not completely against vaccines, but that’s too big a topic to cover here.)  Aluminum has also been linked to breast cancer, kidney failure, dementia, Alzheimer’s, MS, ALS, and Parkinson’s disease.

ANTIMONY

• In certain cases when the Antimony levels are higher than expected, the associated symptoms and toxic effects may not be presented. This is because Antimony (chemical symbol Sb) has two valences: Sb+3 and Sb+5. Sb+3 is the more toxic but is mostly excreted in feces. Sb+5, less toxic, binds less well to body tissues and is excreted mostly in urine. Antimony can be assimilated by inhalationof Sb salt or oxide dust, ingested with (contaminated) foods or fluids, or absorbed transdermally

ARSENIC

Arsenic is a complex metal, that forms a variety of compounds, either inorganic or organic. Organic Arsenic compounds like Arsenobetaine, Arsenocholine, Arsenosugars and Tetramethylarsonium salts contain carbon and aremainly found in sea-living organisms, however occasionally they can be found in species living on land. Inorganic forms of Arsenic, such as Arsenite and Arsenate are generally known to be more toxicand are mainly of geological origin. These can be found in agricultural soil and groundwater used for drinking or irrigation.

BISMUTH

This element is considered to be only slightly toxic with ingestion of gram quantities necessary before signs of toxicity occur. Only between 5 and 10% of orally ingested, soluble bismuth salts are absorbed into the blood. Bismuth is a byproduct of lead and copper ore refining. Bismuth has therapeutic uses with antimicrobial, anti-secretory and anti-inflammatory actions.

NICKEL

With the exception of specific occupational exposures, most absorbed Nickel comes from food or drink, and intakes can vary by factors exceeding 100 depending upon geographical location, food type, and water supply. Depending upon chemical form and physiological factors, from 1 to 10% of dietary Nickel may be absorbed from the gastrointestinal tract into the blood. Urine reflects recent exposure to nickel and may vary widely in Nickel content from day to day due to the above factors. 

How do you minimize your heavy metal exposure?

• Stop smoking!  And limit your exposure to second-hand smoke if you can.
• Choose a fluoride-free toothpaste.  Other toothpastes plus the physical action of brushing will clean your teeth just fine.
• Buy your fish wild caught, not farmed, and not from the Atlantic.  Choose Alaskan salmon if you have the choice!   Fish to avoid, due to mercury content: tuna, orange roughy, swordfish, shark, halibut, and snapper.  Fish to consider instead: cod, whitefish, tilapia, ocean perch, shrimp, flounder, scallops, clams, and catfish.
• Choose non-aluminum based antiperspirants – or just choose a deodorant and not an antiperspirant at all, if you can handle it.  Certain natural deodorants work quite well when used in conjunction with a healthy, non-toxic lifestyle.  (Remember that sweat is one of the body’s mechanisms to eliminate toxins – the more toxic you are, the smellier you tend to be!)
• If you purchase herbal remedies imported from overseas, make sure you do so from a trusted brand that tests for heavy metals and certifies their products are uncontaminated.
• Avoid over-the-counter meds that contain aluminum.  Aluminum is sometimes listed as an active and sometimes as an inactive ingredient, so read your labels.  You shouldn’t need to be taking antacids regularly anyway.  If you are, you’re just treating the symptom, not the cause.  The same is true for continuous use of other over-the-counter meds.
• Avoid products containing baking powder in the ingredient list, unless specifically stated that it does not contain aluminum.  If they don’t say that it doesn’t, assume that it does.  Same goes for self-rising flour.  (Generally you shouldn’t be eating processed crap anyway, if I haven’t said that enough.)
• Consider having your mercury amalgams replaced, if it’s an option for you financially.  There are biological (or holistic) dentists that can do this for you.
• Replace your aluminum pans.  Cast iron or stainless steel are a good choice.  They’re harder to scrub clean, though.
• Make sure you’re getting your daily dose of antioxidants.  These will both counter the effects of some heavy metals, and improve your body’s natural detoxification mechanisms.
• Make sure you’re getting your daily dose of chlorophyll.  Translation: eat your greens, the darker the better!  This will also help you to eliminate toxins.
• Make sure you’re getting your daily dose of fiber.  Fiber helps to bind and eliminate toxins of all kinds.  Whole grains and veggies are a great source.
• Drink plenty of water!  This flushes out your cells, and helps to prevent constipation, which will clearly impede toxic elimination.

Heavy metals contamination

Metals in Soil 

Mining, manufacturing, and the use of synthetic products (e.g. pesticides, paints, batteries, industrial waste, and land application of industrial or domestic sludge) can result in heavy metal contamination of urban and agricultural soils.  Heavy metals also occur naturally, but rarely at toxic levels.  Potentially contaminated soils may occur at old landfill sites (particularly those that accepted industrial wastes), old orchards that used insecticides containing arsenic as an active ingredient, fields that had past applications of waste water or municipal sludge, areas in or around mining waste piles and tailings, industrial areas where chemicals may have been dumped on the ground, or in areas downwind from industrial sites.   

Excess heavy metal accumulation in soils is toxic to humans and other animals.  Exposure to heavy metals is normally chronic (exposure over a longer period of time), due to food chain transfer.  Acute (immediate) poisoning from heavy metals is rare through ingestion or dermal contact, but is possible. Chronic problems associated with long-term heavy metal exposures are: 

! Lead – mental lapse. ! Cadmium – affects kidney, liver, and GI tract.  ! Arsenic – skin poisoning, affects kidneys and central nervous system

Metals in water

Heavy metals occur in the earth’s geological structures, and can therefore enter water resources through natural processes. For example, heavy rains or flowing water can leach heavy metals out of geological formations. Such processes are exacerbated when this geology is disturbed by economic activities such as mining. These processes expose the mined-out area to water and air, and can lead to consequences such as acid mine drainage (AMD). The low pH conditions associated with AMD mobilise heavy metals, including radionuclides where these are present.  Mineral processing operations can also generate significant heavy metal pollution, both from direct extraction processes (which typically entail size reduction - greatly increasing the surface area for mass transfer - and generate effluents) as well as through leaching from ore and tailings stockpiles.

Metals as contaminants in food

The most common contaminants of foods are what are known as “heavy metals” which include mainly mercury, lead, and cadmium. Food like commercial high fructose corn syrup, an ingredient often found in the top five ingredients in many food stuffs shows significant levels of mercury.  Almost a third of 55 popular brand name food and beverage products contain this high fructose corn syrup as either the first or second ingredient. Mercury can cause serious brain damage, deafness, and blindness. The biggest cause of mercury in our food supply is from industrial waste and often is consumed by eating fish and shellfish. Lead is another toxic metal that enters our bodies through drinking water and through the food we eat.  In certain areas, heavy lead pollution comes from leaded petrol that leaks into the environment. Cadmium poisoning isn’t as prevalent, but does contaminate our food supply from local industrial and mining operations.

In air

Toxic air pollutants, also known as hazardous air pollutants (HAP), are pollutants which can cause serious health and environment effects. Most air toxics originate from anthropogenic sources like mobile sources (e.g., cars, trucks, buses), stationary sources (e.g., factories, refineries, power plants), indoor sources (e.g., some building materials and cleaning solvents), and even released from natural sources such as volcanic eruptions and forest fires. Examples of toxic air pollutants include benzene (in gasoline), perchlorethlyene (in dry cleaning chemicals), methylene cvahloride (in solvents and paint strippers), asbestos, toluene, arsenic, and metals such as zinc, cadmium, mercury, chromium, and lead compounds.

People exposed to toxic air pollutants due to poisonous smog at ample concentrations and durations may have increased chances of cancer, reproductive and birth defects, immunological damages, and retarded neurological development. Some persistent toxic air pollutants accumulate in body tissues because unlike organic pollutants, toxic metals do not decay.

Metal Contaminants in Biosolids

            Because metals are elements, they do not breakdown in the environment; the only possible change is transformation to a different form, often resulting in more toxic compounds (Ridley et al. 44). Tin, arsenic, selenium, tellurium, lead, gold, mercury, titanium, platinum, and palladium have all been reported to undergo conversion into organic forms by microorganisms in the environment and in organic form are bioaccumulative toxins, particularly to the central nervous system. (Ridley et al. 44). Metals in soils repeatedly applied with biosolids will necessarily have increased metal concentrations

Relationship to living organisms

Living organisms require varying amounts of "heavy metals". Iron, cobalt, copper, manganese, molybdenum, and zinc are required by humans. Excessive levels can be damaging to the organism. Other heavy metals such as mercury, plutonium, and lead are toxic metals and their accumulation over time in the bodies of animalscan cause serious illness. Certain elements that are normally toxic are, for certain organisms or under certain conditions, beneficial. Examples include vanadium,tungsten, and even cadmium.