Lead poisoning

Lead is present in many forms in the environment, but has no recognized biological benefit in humans. Lead can damage nearly every organ system. In fact, extremely high levels of lead can be fatal. However, lead poisoning is often treatable and usually preventable.


Causes/associated factors
Lead can enter the body through inhalation, ingestion or during fetal development. Single, large exposures are not the only culprit -- small doses over an extended period of time can cause lead poisoning. What's important is the total amount of lead that has collected in the body.
People with certain health conditions are at higher risk for lead poisoning, including poor nutrition or high fat consumption and dietary deficiencies of zinc, calcium or iron. For children, seizure disorders and autism may increase the risk of lead poisoning.

For adults, lead is considered toxic when more than 75 micrograms per day are inadvertently absorbed. Studies have shown that lead intake of 30 micrograms has the potential to injure nerves and red blood cells or raise blood pressure. However, any amount of lead in your bloodstream can be harmful.


Sources of lead
Most people have some amount of lead in their systems. People living in inner cities often have higher exposures to lead. According to some estimates, more than 100 occupations and hobbies may lead to lead exposure, including:
plumbing and pipe fitting
lead mining, smelting, refining or soldering
ship building
vehicle and boat repair
gas station work
glass, plastic, battery and rubber product manufacturing
printing
police work and target shooting at firing ranges
construction work
steel cutting and welding
painting or making stained glass or glazed pottery
making lead shot fishing sinkers
The greatest environmental factors include:

leaded paint
auto emissions
contaminated drinking water (usually from the plumbing in your home, not the water source)
lead-soldered food cans (which were banned in the United States in 1996)
lead-soldered plumbing
improperly fired lead ceramic glazes

Lead exposure and children
Children are more sensitive to lead than adults. The U.S. Food and Drug Administration (FDA) considers the "total tolerable" daily lead absorption in children under age 6 to be 6 micrograms. For children, especially those under age 6, lead exposure can affect growth and physical development, hearing, behavior, blood pressure and blood production. It can even contribute to brain damage. Fortunately, the percentage of young children with problematic blood lead levels has dropped dramatically over the last 20 years.
The absorption of lead is greater among children living near lead processing smelters and among children of workers who bring leaded dust into their homes on their work clothing. Children may develop lead poisoning by ingesting paint chips from lead-based paint or inhaling dust from surfaces painted with lead-based paint. (The use of lead-based paint has been banned since 1978, but many older homes and buildings still contain this type of paint.) Children playing near roads may also come in contact with lead. Although leaded gasoline is no longer used for automobiles, the lead in dust from past auto emissions may have contaminated nearby soil.


Signs/symptoms
Lead poisoning often has no symptoms. The probability of symptoms rises with increased levels and exposure, however. When symptoms are present, they vary from person to person. Symptoms of mild to moderate lead poisoning may include:
muscle pain
fatigue
irritability
lack of energy
abdominal pain
joint pain
difficulty concentrating
headache
tremor
vomiting
weight loss
Cases of severe lead poisoning may be fatal. Symptoms of severe lead poisoning may include:

appetite loss
metallic taste in the mouth
constipation
severe abdominal cramps
altered nerve sensations in extremities
seizures
coma
retarded mental development
chronic hyperactivity
kidney failure
For children, the first symptoms of lead exposure may be problems with behavior and social interaction. Speech and hearing difficulties and learning problems are also common. Studies suggest that increased blood levels of lead may be associated with decreased intelligence.


Diagnosis
A blood test can determine the level of lead in the blood. If the lead level is high, urine testing and more blood work may be done to determine if the kidneys have been damaged. X-rays may also be done.

Treatment
In most cases, the affected person simply needs to be removed from the source of lead exposure. If the lead is in your home or a home you visit regularly, do not return until repairs and cleaning are complete. Make sure that all possible sources of lead are removed.
Chelation therapy
If lead levels are high, chelation therapy may be recommended. Chelation is a chemical reaction that occurs when a substance known as a chelating agent combines with certain metals. During the procedure, a chelating agent will be given either intravenously (into a vein), intramuscularly (into a muscle) or orally (by mouth). By binding to the metal in your bloodstream, the chelating agent will quickly help your body get rid of the dangerous metal through your urine or stools.

Risks of chelation therapy
In addition to removing the toxic metal(s) from your body, the chelating agent may also remove other metals, such as magnesium. For this reason, vitamin and mineral supplements may be used after chelation therapy. Repeat treatments may be needed if the metals stored within your bones and tissues seep out and cause another bout of harmful metal accumulation in your blood. Excessive treatments may damage the kidneys or liver.


Complications
Lead poisoning can lead to kidney failure and gout (a disorder that causes sudden, recurring attacks of painful arthritis). It can also affect developing blood, bones and teeth. Any body system can be adversely affected by lead, and extremely high lead levels can be fatal.

Pregnancy-specific information
Some women may have lead stored in their bones. During pregnancy, the release of lead from the bones is accelerated. Sometimes, lead can cross the placenta (a structure in the womb that develops during pregnancy to nourish the fetus and help it discard waste). If this happens, your baby may develop neurological problems, not grow well or be born prematurely. You may also have a higher risk of miscarriage or stillbirth.
For pregnant women, the FDA has set "total tolerable" intake levels of lead at 25 micrograms a day. Pregnant women are encouraged to avoid the frequent use of lead crystal ware, as well as the use of lead crystal baby bottles. Itthe work is being done to decrease your chances of exposure to lead dust.


Senior-specific information
Growing older is not a risk factor for lead poisoning.

Prevention
The best way to prevent lead poisoning is to avoid lead exposure. In conjunction with state programs, the Centers for Disease Control and Prevention (CDC) recommends screening for anyone at increased risk of lead exposure. Although screening requirements vary by state and are related to local conditions, lead screening is often done at age 1 and again at age 2.
Other government agencies also play a role in preventing lead poisoning. The Occupational Safety and Health Administration (OSHA) has established standards for the maximum level of lead allowed in the air in the workplace. The Environmental Protection Agency (EPA) limits the amount of lead in gasoline to 0.05 grams per gallon with relation to air quality. The EPA also monitors the amount of lead present in drinking water. Finally, the FDA regulates lead contamination in food, some of which comes from solder in old or imported cans and glazes on ceramic dishes.

To protect you and your family from lead poisoning, keep the following suggestions in mind.

Test for lead in your home, especially if it was built before 1978. The EPA recommends using a lead inspector, risk assessor or a certified laboratory.

If you have lead paint in your home, do not remove it yourself. Improper removal can increase your exposure. Instead, have a specially trained lead removal contractor do the work. This also applies if youxposure.

Have the lead content of your water tested by a competent lab.

Use cold water for cooking and drinking. Itally for food, including antiques.

Avoid storing food in opened cans, especially if the cans have been imported.

Wines bottled before 1996 may have tin-coated lead foil capsules. Remove the entire foil before use. Before uncorking the wine, wipe the neck, rim and top of the cork with a clean wet cloth to prevent lead contamination.

Avoid the use of eye cosmetics imported from the Middle East that contain kohl, also called al-kahl, kajal or surma. (Kohl contains lead.)

Avoid the use of foreign digestive remedies that contain lead, such as Alarcon, Azarcon, Coral, Greta, Liga, Maria Luisa or Rueda. (Greta is 99 percent lead oxide).

Avoid the use of litargirio powder, a burn and wound remedy imported from the Dominican Republic that contains up to 79 percent lead. The powder may also be used as a deodorant or foot fungicide.