Lead (Pb)

How You Can Be Exposed to Lead?

Lead is a component in thousands of products including lead-based paints, lead solder, electrical fittings and conduits, tank linings, plumbing fixtures, and many metal alloys. Although many uses of lead have been banned, remnants from old construction projects or equipment can occasionally be found. Additionally, lead based paints continue to be used on bridges, railways, ships, and other steel structures because of its rust- and corrosion-inhibiting properties. Significant lead exposures can also occur when paint is removed from surfaces previously covered with lead-based paint. 

Operations that can Generate Lead Dust and Fumes

  • Demolition of structures
  • Torch cutting and welding
  • Use of heat guns, sanders, scrapers, or grinders
  • Abrasive blasting 

Lead is a toxic metallic element, which can enter the body through a variety of means, some of which include:

  • Inhaling dust or fumes
  • Consuming contaminated food
  • Using contaminated eating utensils

Route of Exposure

Ingestion of lead particles is the main route of exposure. This can occur if you do not wash your hands or properly clean off lead-contaminated items. You then accidentally ingest the lead from the previously touched contaminated surface when eating, drinking, or applying cosmetics. 

  • Once in the bloodstream, lead is primarily distributed among three compartments - blood, mineralizing tissue, and soft tissues. The bones and teeth of adults contain more than 95% of total lead in the body
  • In times of stress (particularly pregnancy) the body can mobilize lead stores, thereby increasing the level of lead in the blood
  • The half-life of lead in adult human blood has been estimated as 30-40 days 
    • The above half-life only applies to lead in the blood, not other tissues
  • The body accumulates lead over a lifetime and normally releases it very slowly 
  • Both past and current elevated exposures to lead increase risks for adverse health effects from lead

Health effects

Chronic overexposure (blood lead levels above 40µg/100g) occurs when your body cannot clear lead from your body quicker than your exposure rate.

  • Can damage nervous, urinary, and reproductive systems
    • Studies on males show a severe depression of sperm count and decreased function of the prostate and/or seminal vesicles
    • Chronic exposure to lead in humans can affect the blood and the nervous system 
  • Those who intend to have children should maintain blood lead levels below 30µg/100g to protect fertility and the developing fetus

Note that these effects are toxic to all humans but are much more toxic to children, infants, and unborn children. Lead is especially toxic to unborn children, affecting their development, birth weight, and in severe cases causing spontaneous abortions.

Signs/symptoms of Lead Poisoning 

  • Metallic taste in mouth
  • Muscle/joint pain or weakness
  • Problems with memory or concentration
  • Loss of appetite/weight loss
  • Gastrointestinal/digestive problems
  • Irritability or Anxiety

Work Practices

  • Employees must wash hands frequently when working around lead, especially before eating
  • No smoking, eating, drinking, application of lip balm, or cosmetics is permitted
  • Avoid cleaning methods which create airborne lead dust or fumes. HEPA vacuums should be used
  • Pregnant women may want to consult with an occupational health physician before working around lead

Personal Protection

Respiratory protection such as a tight-fitting respirator with HEPA cartridges may be required where over-exposure is likely.

OSHA Requirements

OSHA regulates exposure to lead and is applicable in areas where lead exposure exceeds action limits. The regulation has many specific requirements for exposure monitoring, medical surveillance, safe work practices, and PPE.  Contact University Health and Safety to help assess lead exposure concerns in your work area.   

Questions 

If you have questions on this topic, please contact University Health and Safety at (612) 626-6002.