Who is Looking After Our Kid's?
CHAPTER 8
Toxic heavy metals: lead, cadmium, mercury, antimony and aluminum
Although other metals can be toxic under certain circumstances, lead, cadmium, mercury, antimony and aluminum are generally considered to be foremost in public health concerns. There is far more awareness of the health hazards from these toxic metals than from the volatile organic compounds, and therefore there is considerable progress in toxic metals control. Nevertheless, they still remain a health threat to the public, especially to children.
Lead
Numerous reports have shown that lead exposures in children can result in Intelligence quotient (IQ) deficits. (1,2) The incidence of documented lead toxicity in children has declined substantially since leaded gasoline was phased out in the early 1980s. Six potential sources for lead exposure remain:
- Flaking lead paint in older buildings: Houses or apartments built before 1950 are almost certain to have lead paint on their walls. When construction occurred between 1950 and 1980, chances are about 50-50 that lead is present (although lead paint from houses was banned after 1972). Do-it- yourself lead testing kits are available for between $35.00 and $50.00.
- Tap water in older buildings with lead pipes or in newer buildings in which lead solder was used to seal connections in the plumbing.
- Outdoor soil contamination as a fallout from earlier years when leaded gasoline was used. Incompletely washed fruits and vegetables may contain traces of this contaminated soil. Another major source is outdoor dust blowing into houses.
- Activities involving lead solder.
- Some art supplies. Although lead has been outlawed for most paints, it is not outlawed in artist's paints.
- Prolonged exposure at pistol and rifle firing ranges.
- Older houses should be checked for lead. If lead paint is present, alternatives include removal of the paint, which should always be done by professionals with protective gear, or to repaint the surfaces, sealing in the older paint (check with local building codes).
- It is probably advisable to check tap water for lead, unless it is certain there is no lead in the plumbing. Fruits and vegetables should be washed thoroughly. Houses should be kept free of dust.
Cadmium
Cadmium, a neurotoxin, has been implicated in mental retardation. (3) Increased levels have been found in placentas of mothers who smoke and may cause low birth weight in babies. (4) Children and pregnant women should not be exposed to passive tobacco smoking from second-hand smoke. Cadmium may also come from tap water when cadmium alloys have been used for soldering plumbing joints.
Mercury
Mercury is a neurotoxin. It tends to accumulate in the body and is not easily expelled. The classical necrological and disordered behavioral symptoms of mercury poisoning are exhibited in Alice in Wonderland by the Mad Hatter. For hatters in the Victorian era, mercury poisoning was an occupational hazard.
In 1989, the EPA banned mercury from indoor paints after the case of a four year old boy made severely ill as a result of indoor paint exposure. However, exterior coatings are still allowed to contain mercury, and stored paint manufactured before the ban may also contain mercury. (National Pesticide Telecommunication Network at 800-858-7378 maintains a listing of older paints that may contain mercury.)
Perhaps the most controversial and lively issue concerning mercury today surrounds the silver/mercury dental fillings. According to reports, mercury constitutes about 50% of these fillings. Because mercury vaporizes above 10°F, an estimated 3 to 17 mcg of mercury are absorbed daily into the system from mercury amalgams. The new composite, porcelain, or ceramic fillings should be used for all future dental work.
Antimony
High levels of antimony, sometimes used as a flame-retardant in pillows and mattresses, has been found in children with autism with significant frequency, according to Jon Pangborn, PhD, in his research report delivered at the Autism Research Institute Conference in Chicago in June of 1996.
Aluminum
Aluminum is a relative newcomer to the list of toxic metals, long having been considered harmless. It has been implicated as a contributory cause of Alzheimer's disease. (5) Elevated hair aluminum in children, especially when attended with elevations of lead, have been found to cause decreased visual motor performance. (6)
We routinely recommend hair tests for ADHD children, primarily as a screening test for lead. Rather surprisingly, the most consistent finding is that of elevated hair aluminum.
Aluminum comes from foods cooked or stored in aluminum pans and aluminum foil. Leafy vegetables, rhubarb, and apples cooked in aluminum pans are prone to leach the metal from the pan. Pressure cookers are especially likely to impart metal into the food. Tap water may contain aluminum when it is used in water reservoirs to flocculate silt from the water. Other sources include antacids taken for stomach trouble, some antiperspirants, food additives, and milk substitutes.
Clinical Management of Toxic Heavy Metals
We employ the hair test in screening for heavy metals, although blood tests for lead should also be done in ADHD and learning disabled children. When elevated levels are found, the first responsibility is to seek and eliminate the source as much as possible. When blood lead exceeds 10 mcg, the child should be referred to a medical center for appropriate therapy. This, however, is increasingly uncommon-we have yet to see a single case with this level.
Except in the more severe cases of heavy metal toxicity, we believe treatment should be nutritional, which works slowly but effectively and safely. Even here, if a child is ill and heavy metals are suspected as a contributory cause, treatment should not be attempted without professional guidance.
Treatment measures may include, but are not limited to, the following:
- Vitamin C: increases the turnover rate of toxic metals and reduces damage by scavenging free radicals generated by the toxins. (7)
- Sulfur-containing amino acids from sulfur-rich food such as garlic, onions, beans, and lentils.act as chelating or binding agents for the heavy metals,forming relatively inert bonds with the heavy metals, in which form they can be carried out of the body. (8)
- Vitamin B1 (thiamine) contains a sulfide-containing thiazole ring, which acts in a similar manner.
- Sulfide-containing amino acids: glutathione may be the most valuable.
- In addition to garlic seasoning in foods, garlic capsules can be given.
- Nutrient trace minerals including calcium,magnesium, zinc, manganese, copper, selenium, and iron, given as supplements, are of utmost importance in treating the child with heavy metal toxicity for two reasons. First, such a child will almost invariably be deficient in these minerals and, second, these minerals (especially calcium, zinc, copper, and iron) tend literally - to push the toxic metals out of the body as they are replenished. (8)
- Blue-green algae or chlorella, taken as oral supplements, may be the single most effective preventive measure against mercury toxicity. Taken in combination with garlic, these supplements provide a rich supply of sulfhydryl groups, which combine with mercury and help to move it from its intracellular storage positions while at the same time disarming its toxicity. Research, although still in its early phases, tends to confirm this role.
It may not be inappropriate to end this chapter with a true story told by an attorney, Jon Pangborn at the Autism Research Institute Conference in June of 1996: Some years ago, there was a company in which employees had been made ill by lead exposure. The employees sued the company. The company's defense rested on one man, more directly exposed than other employees, who remained perfectly healthy. The company's attorney argued that if this man were not ill, then lead could not be the cause of illness in the others. As it turned out, the man in question was a Mexican. What do Mexicans eat? They eat beans. In this case, they protected the Mexican from the lead. When this knowledge was revealed, presumably the other employees won their case.
References
1. Air Quality Criteria for Lead Research Triangle Park. NC: US Environmental Protection Agency; 1986. 4 volumes. EPA- 600/8-83 028aF.
2. Needleman HL, et al. Deficits in psychological and classroom performance of children with elevated dentine lead levels. N Engl J Med. 1979;300:689-693.
3. Marlow M, et al. Hair mineral content as a predictor of mental retardation. OrthoPsych. 1983;12 (1):26-33.
4. Miller J, et al.; Haley, Berndt, ed Reproductive & perinatal toxicology. Handbook of Toxicology. Washington, DC.
5. Martyn CN, et al. Geographical relation between Alzheimer's disease and aluminum in drinking water. Lancet. 1989;1:59-62.
6. Moon C, et al. Main and interaction effects of metallic pollutants on cognitive functioning. J Learning Disabilities. 1985; 18:217-221.
7. Hume AS, et al. Binding of toxicants by carbonyl & sulfide containing chemicals. Environ Med. 1991 ;8 (3):96- 100.
8. Isaacson RL, Jensen KF, eds. The Vulnerable Brain and Environmental Risks. Vol 2. New York:Plenum Press; 1992:118-120.
Recommended Reading:
Casdorph HR, Walker M. Toxic Metal Syndrome: How Metal Poisonings Can Affect Your Brain. Stamford, CT: Freelance Communications; 1994.