How fast does the body eliminate lead?

September 3, 2008 3:54 PM

My baby recently tested quite high (but not at an emergency level) for lead. He had two tests in a row, so we're pretty sure they're correct. We've got all kinds of information on eliminating lead and we're doing everything we can, but we'd like to make a plan about assessing his progress and considering more serious steps like moving if it's not great. Does anyone know how fast one can expect blood levels to drop after removing the source of exposure?
posted by lgyre to health & fitness (13 comments total)

Do you know what the source of exposure is?
posted by Dumsnill at 4:07 PM on September 3, 2008

not for sure, that's the thing, and why we would consider moving if we can't reliably eliminate it. we do live in an older building and have done some remodeling, so we do have a few ideas...starting with general cleaning of dust and removing some old radiators that may have an underlying layer of lead paint. We're also going to get some testing in our home soon that might give us a better idea.
posted by lgyre at 4:12 PM on September 3, 2008

Pediatric Toxicology (2004) By Timothy Bruce Erickson says:

The distribution of absorbed lead in the body can be modeled using three compartments: blood, soft tissue, and bone. Under steady-state conditions 99% of the lead in blood is attatched to read blood cells. Under chronic exposure conditions, the bone serves as a storage organ and can release lead back into the blood and soft tissues. Absorbed lead is elimated primarily in the urine and bile. In adults the elimination of lead is first order and triphasic with elimination half-lives of 1 week, 1 month, and 10 to 20 years. Pediatric data are lacking, but some reports indicate that the biologic half-life of blood lead in 2-year-old children is about 10 months.

A CDC summary says:

Although the blood generally carries only a small fraction of total lead body burden, it does serve as the initial receptacle of absorbed lead and distributes lead throughout the body, making it available to other tissues (or for excretion).

• The half-life of lead in adult human blood has been estimated to be from 28 days (Griffin et al. 1975 as cited in ATSDR 2005) to 36 days. (Rabinowitz et al. 1976 as cited in ATSDR 2005)

The CDC's Toxicological Profile Information Sheet for lead says:

Blood lead is also considered the most useful tool for screening and diagnostic testing (Moore 1995); the half-life of lead in blood is approximately 36 days (Todd et al. 1996). A second half-life is generally considered to be approximately 4 years (Graziano 1994) and reflects the replenishment of lead in the blood from the bone storage compartment.

posted by RichardP at 4:36 PM on September 3, 2008

It's usually water (lead leaches from solder in old pipes), lead paint (on walls or toys), sometimes from pottery (sometimes glazed using lead-containing chemicals). I've also heard instances where alternative medicine (aruyvedic in particular) has been the agent of the poisoning. The lead is typically ingested by mouth (water, eating paint chips, drinking from suspect pottery). Dust can be an issue in some cases.

Removal of the source is the essential treatment, though sometimes chelation therapy is used, depending on the blood level. I'm not sure how long it takes the lead to clear on its own, but testing is often repeated every month.

Given the significant developmental dangers of lead poisoning for young children, you might want engage a knowledgeable hazardous waste expert to do the assessment as quickly as possible, and maybe move the child, at least until you clarify the source.
posted by jasper411 at 4:42 PM on September 3, 2008

How old is the baby? Also, have you had your own lead levels checked? That might help you trace the source as being something like a toddler getting into paint chips versus something environmental like dust, the water supply or even some nearby source of lead vapor. With your cleanup work, be careful not to stir up more dust. The woodworking community is all over dust collection systems these days with a lot of noise being made about the fact that brooms really excel at stirring up really fine dust.

How far apart, time wise, were the two tests?

As I understand it, lead tends to bio-accumulate. You pick it up fairly easily but don't get rid of it that fast. Be concerned if the level continues to rise.
posted by Kid Charlemagne at 4:45 PM on September 3, 2008

Have any of your neighbors done remodeling, especially exterior paint removal, lately?

I once lived in an old house with a slumlord landlord who just hired some yahoos to strip the exterior paint without proper lead paint removal procedures and equipment. A toddler in the house next door got lead poisoning from the amount of paint dust blowing in their windows.
posted by LobsterMitten at 5:14 PM on September 3, 2008

Call the public health department in your city or state. There will be someone there who is knowledgeable about lead.
posted by theora55 at 6:13 PM on September 3, 2008

Our 6 month old baby tested at a 10, which was borderline for having risk of impairment with continued exposure-- we were alarmed, but knew with a 1911 home it was likely paint or water rather than toys. We had everything tested, and found the paint in the bathroom to be over 50% lead. We remodeled immediately, and within six months, the test came back at a 6. By the two year check up, it was a 2, and we have no signs of development issues. Should note that you can attack on two fronts: find the source and deal with it aggressively, as well as adopt a diet of foods that can help remove the lead. Speak to a pediatrician about that diet, as metafilter is not the place to get specific medical information, of course. Best of luck to you and yours.
posted by Arch1 at 8:33 PM on September 3, 2008 [1 favorite has favorites]

Forgot: your city, if you live in a major metro, may have testing facilities for water and paint. (We provided samples after getting a water kit and pulling chips, as well as swabbing.) Getting the answer was worth a lot more than the $90 bucks or so all of that testing cost.
posted by Arch1 at 8:35 PM on September 3, 2008

"Screening for Lead Levels in Childhood and Pregnancy
U.S. Preventive Services Task Force

Release Date: December 2006

Summary of Screening Recommendations / Supporting Documents
Summary of Recommendations

Children

* The U.S. Preventive Services Task Force (USPSTF) concludes that evidence is insufficient to recommend for or against routine screening for elevated blood lead levels in asymptomatic children aged 1 to 5 who are at increased risk. (Go to Clinical Considerations for a discussion of risk.)

Rating: "I" statement.
* The USPSTF recommends against routine screening for elevated blood lead levels in asymptomatic children aged 1 to 5 years who are at average risk.

Rating: "D" recommendation.

Pregnant Women

* The USPSTF recommends against routine screening for elevated blood lead levels in asymptomatic pregnant women.

Rating: "D" recommendation.

Rationale

Importance: Blood lead levels in children have declined dramatically in the United States over the past two decades. However, segments of the population remain at increased risk for higher blood lead levels. Even relatively low blood lead levels are associated with neurotoxic effects in children. Severely elevated blood lead levels in symptomatic pregnant women are associated with poor health outcomes; however, lead levels in this range are rare in the U.S. population.

Detection: There is good evidence that venous sampling accurately detects elevated blood lead levels and fair evidence that validated questionnaires are modestly useful in identifying children at increased risk for elevated blood lead levels.

Benefits of Detection and Early Intervention: The USPSTF found good quality evidence that interventions do not result in sustained decreases in blood lead levels and found insufficient evidence (no studies) evaluating residential lead hazard control efforts (i.e., dust or paint removal, soil abatement, counseling, or education) or nutritional interventions for improving neurodevelopmental outcomes in children with mild to moderately elevated blood lead levels. The USPSTF found no evidence examining the effectiveness of screening or interventions in improving health outcomes in asymptomatic pregnant women. Given the low prevalence of elevated blood lead levels in children at average risk and asymptomatic pregnant women, the magnitude of potential benefit cannot be greater than small.

A theoretical benefit of screening is that identification may prevent lead poisoning of other individuals in a shared environment, but the magnitude of this theoretical benefit is uncertain.

Harms of Detection and Early Treatment: There is good quality evidence that chelation treatment in asymptomatic children does not improve neurodevelopmental outcomes and is associated with a slight diminution in cognitive performance. Chelation therapy may result in transient renal, hepatic, and other toxicity, mild gastrointestinal symptoms, sensitivity reactions, and rare life-threatening reactions. Residential lead-based paint and dust hazard control treatments may lead to acutely increased blood lead levels from improper removal techniques. Potential harms of screening are false-positive results, anxiety, inconvenience, work or school absenteeism, and financial costs associated with repeated testing. Although the exact magnitude of these known and potential harms is uncertain, the overall magnitude is at least small.

No studies have directly addressed the harms of screening and interventions for pregnant women. Although there is little specific evidence concerning the potential harms of interventions for pregnant women with elevated blood lead levels, the magnitude of harms from such interventions is also at least small.

USPSTF Assessment: The USPSTF concludes that the evidence is insufficient to assess the balance between potential benefits and harms of routine screening for elevated blood lead levels in children at increased risk. Given the significant potential harms of treatment and residential lead hazard abatement, and no evidence of treatment benefit, the USPSTF concluded that the harms of screening for elevated blood lead levels in children at average risk and in asymptomatic pregnant women outweigh the benefits."
http://www.ahrq.gov/clinic/USpstf/uspslead.htm
posted by dougiedd at 10:21 PM on September 3, 2008

Hi, you will find a whole library about this subject from a comprehensive perspective with news, facts and studies.
posted by watercarrier at 5:02 AM on September 4, 2008

Not to scare you, but one more thing to keep in mind. Recent evidence suggests that the established "safe" levels are actually dangerously high, and that damage can occur at blood lead levels as low as 2µg/dl. (The current "action level" is 10µg/dl.) See Gilbert & Weiss, A rationale for lowering the blood lead action level from 10 to 2 μg/dL, Neurotoxicology. 2006 September; 27(5): 693–701. (Free Pubmed link.)
posted by j-dawg at 8:27 AM on September 4, 2008

Be wary of sources claiming to sell miracle supplements and tablets to remove lead from the body. There is a lot of quackery in this area; you'll want to do your homework.
posted by LobsterMitten at 10:41 AM on September 4, 2008