Bernard Windham, MD
Mercury and lead are extremely neurotoxic and cytotoxic, but their combined synergistic effect is much worse. A dose of mercury sufficient to kill 1% of tested rats, when combined with a dose of lead sufficient to kill less than 1% of rats, resulted in killing 100% of rats tested(1). Thus with combined exposure, the safe dose is 1/100 as much as the dose individually. Studies in Australia have confirmed similar relationships hold for people. This means most people in the US are getting dangerous levels of these metals, enough to cause some neurologic effects.
Similar is true for synergistic effect with other toxic metals like arsenic, and with other toxic chemicals like PCBs(2). The level of mercury thimerosal in vaccines has been shown to be highly neurotoxic, but the effect was found to be much larger due to the synergistic effect with aluminum, which is also in most vaccines(3). Studies using US CDC data have found thimerosal from vaccines to be major factors in autism and ADHD(4), along with prenatal rhogam shots which contain high levels of mercury thimerosal and are given to some RH negative women during pregnancy.
Autism has increased in the US more than 10-fold in the last decade. According to the Florida Department of Education, the numbers increased from approximately 300 to over 4000 during this time period. There have likewise been large increases in the number of children with ADHD and other developmental conditions, according to the National Academy of Sciences and other sources. A major factor in this appears to be the large increase in vaccinations given to infants. (more documentation is available at the childrens neurological page, www.home.earthlink.net/~berniew1/indexk.html)
There was an increase of over 45% in learning disabilities in Pennsylvania between 1990 and 2000(5). But the study showed that the county highest on the Chemical Pollution Scorecard, Montgomery, had an increase more than double that of the rest of the state. Montgomery County had an increase in ADHD of 32.7% and an increase in autism of 310%.
ps. note that a high percentage of Gulf state residents have been documented to have high levels of mercury exposure (Mobile Register study, www.home.earthlink.net/~berniew1/flhg.html)
Schubert J, Riley EJ, Tyler SA. Combined effects in toxicology. A rapid systematic testing procedure: cadmium, mercury, and lead. Toxicol Environ Health 1978;4(5/6):763-776.
2. Philippe Grandjean P, White RF et al. Neurobehavioral deficits associated with PCB in 7-year-old children prenatally exposed to seafood neurotoxicants. Neurotoxicology and Teratology 2001;223(4):305-317.
3. Haley, BE, Pendergrass JC, Lovell, M, Univ. of Kentucky Chemistry Dept., paper presented to the Institute of Medicine Immunization Safety Review Committee, Spring 2001, and on medical lab website, www.altcorp.com
4. Pennsylvania Dept. of Education, 2003, Study of learning disability incidence in Montgomery County, Pennsylvania, 1990 and 2000; & ” Polluting Our Future: Chemical Emissions in the U.S. that Affect Child Development and Learning,” by Physicians For Social Responsibility, at (202) 898-0150, firstname.lastname@example.org
5. Geier M.R., Geier DA; Thimerosal in Childhood Vaccines, Neurodevelopmental Disorders, and Heart Disease in the U.S. ; J of Amer Physicians and Surgeons, Vol 8(1), Spring 2003; & Bradstreet J, Geier DA, et al, A case control study of mercury burden in children with Autisitic Spectrum Disorders, J of Amer Physicians and Surgeons, Vol 8(3), Summer 2003.