Smoke Pot, Get Lead Poisoning?

Dangerous Lead Particles Found in Street Bags of Marijuana

Medically Reviewed by Louise Chang, MD on April 08, 2008

April 9, 2008 -- Here's yet another reason to "just say no" to drugs: Smoking marijuana could lead to lead poisoning. Doctors in Germany have linked a mysterious outbreak of lead intoxication to contaminated street supplies of marijuana.

In a letter to the New England Journal of Medicine, Franziska Busse, MD, of the University Hospital Leipzig and colleagues detail a puzzling occurrence of lead poisoning symptoms over a 3- to 4-month period among patients aged 16 to 33 years old. Twenty-nine patients at four different hospitals had abdominal cramps, nausea, fatigue, and anemia -- classic signs and symptoms of lead intoxication.

Yet the source of the lead remained inexplicable. After eight weeks of investigation, Busse and colleagues finally found a common link: all of the patients admitted to smoking pot on a regular basis, either in joint form or through a water pipe.

Tests done on remaining supplies from some patients revealed traces of lead particles mixed with the marijuana leaves. Lead's grayish color allowed the metal to blend easily with the illicit drug. The large size of lead particles found in one package strongly suggested that the poisoning did not result from soil contamination. Busse writes that police suspect street dealers of deliberately lacing street bags of marijuana with the toxic metal in an effort to increase profits. The weight of the lead particles found in the supplies studied would roughly translate into a profit of $1,500 per kilogram of marijuana.

An anonymous screening program involving 145 people ultimately showed that about two-thirds of the participants had high levels of lead in their blood, requiring treatment. For example, a male patient who smoked nine joints a week had a blood lead level nearly 50 times greater than normal.

Lead poisoning can have serious effects on every part of the body. It can damage the nervous system, impair fertility, and lead to memory and concentration problems. Severe lead poisoning can lead to death. Smoking lead is particularly dangerous, because it allows the metal to be easily absorbed into the airways.

The letter appears in the April 10 issue of the New England Journal of Medicine.