Lead was a component of gasoline for motor vehicles, but, was phased out from 1973 to 1995 and Federal law caused removal of lead from paint in 1978. Since lead was removed from gas and paint there has been a marked reduction of blood lead levels on the average for people in the United States. Lead persists in our environment and results in “cognitive dysfunction, neurobehavioral disorders, neurological damage, hypertension, and kidney damage”. Acute lead toxicity should be treated with chelation.
The Communicable Disease Control Center lists lead as the number one environmental threat to children in this country. Even low blood levels of 10 mcg./dL can cause nervous system problems. Drinking water supplies 20% of the daily dose of lead for the majority of our population and we continue to have lead in our plumbing pipes, connections, and solder. Water should not contain more than 10 ppb (parts per billion) of lead but even school drinking fountains continue to show 20 ppb. “Lead-free” brass fixtures are still allowed to contain some lead.
The District of Columbia water system has a serious lead problem. A chemical added to the water to kill bacteria (chloramine) caused the corrosion of lead pipes that releases lead into the water supply.
Lead can also be found in ceramics, food stored in containers with lead based paints, leaded crystal, cigarette smoke, etc. Vinyl mini-blinds made before 1996 contain lead. Soft vinyl products, especially lunchboxes may have 90 times the legal limit of lead in paint. Some Asian herbal products have been found to be contaminated with lead. Workers in ammunitions, batteries, sheet lead, solder, some plumbing fixtures, ceramic glazes, caulking, radiation shields, circuit boards, military equipment, and some hospital equipment are at high risk for lead.
People today have 500-1,000 times as high blood levels of lead as people in pre-industrial societies. We absorb lead through gastrointestinal and respiratory systems. Increased intake of calcium in infants, children and animals reduces the absorption of lead. Leaded gasoline (tetraethyl or alkyl-lead) is easily absorbed by the skin and is still legal in aircraft, watercraft and farm machinery.
After absorption, 99% of lead is bound to red blood cells for 30-35 days, it is then absorbed by soft tissues of the body for four to six weeks. Up to 80-95% of lead is stored in bones in adults and 70% of lead is stored in bones in young children. Lead is stored for many years in the bones and conditions which increase bone turnover, such as pregnancy, hypothyroidism, osteoporosis and cisplatin chemotherapy mobilize bone stores and can cause symptoms of acute lead toxicity.
“…There is no measurable level of lead in the body below which no harm occurs.” Lead levels above 10 mcg/dL are excessive for infants, children, and women of childbearing age.
One of the main routes of toxicity of lead is interfering with the production of the heme portion of hemoglobin, which causes anemia and fatigue. There is reduction in the release of GABA neurotransmitter in the central nervous system with lead toxicity, which results in behavior disorders. Lead can cause a delayed maturation of red blood cells by interfering with certain enzymes.
Lead in the body can be moved easily between bone and blood. Lead can be easily transferred from the pregnant mother to the fetus.
Lead mimics calcium and takes the place of calcium in many sites, interfering with vital chemical functions. It interferes with the electrical firing of nervous system cells, which interferes with nervous system functions. Lead interferes with brain function, especially in young children, with high lead levels correlating with lower IQ’s.
Even low lead accumulation correlates with a gradual loss of kidney function with aging. High lead levels correlate with increased risk of all types of cardiovascular disease. Lead interrupts the conversion of vitamin D to 1,25-dihydroxyvitamin D, the active form, which takes place in the kidney. Lead is now considered a probable human carcinogen, especially for stomach, lung, and bladder cancers.
The CDC recommends that when children with blood lead levels above 25 mcg./dL, the source of the lead should be identified and removed. If that is not possible, the child should be moved from the source of exposure. The use of a chelating agent, such as EDTA or DMSA, should be considered when blood levels are 45 mcg./dL and above, but chelation is not completely free of adverse effects. There is no definite evidence that chelation reverses nervous system damage.
CONCLUSION: Many adults and children are at risk for neurologic damage, cardiovascular disease, kidney disease, and cancer as a result of lead in the body. Attempts should be made to remove the source of lead and to remove the lead load of the body safely, but chelation therapy should be used cautiously. ” …There is no measurable level of lead in the body below which no harm occurs.” Lead is now considered a probable human carcinogen.
NOTE: The chemical added to the water by the DC water and Sewer Authority in Nov. 2000, in Washington, DC, was chloramine. The chloramine resulted in corrosion of lead pipes and of solder containing lead, releasing the lead into the water. Chloramine containing water is not advised for kidney dialysis, fish tanks, and laboratories. Orthophosphate has been added to the D.C. water since 2004 to coat the inside of pipes and protect them from the corrosive action of chloramine.
The San Francisco Public Utilities Commission added chloramine to the water in San Francisco in 2004. People who drink or cook with San Francisco tap water should have their water tested for lead. San Francisco water should not be used for kidney dialysis, fish tanks, or laboratories.