Lead Exposure

1
Lead Exposure

• Environmental Health
• Successes and Challenges
• ES 210 Spring 2006

2
Historical Uses of Lead

• 8,000 year material and historical record of use
  in ancient worlds
• Uses in ancient Egypt, Rome, China
• Uses in Medieval Era

3
Historical Uses of Lead

• First mined in Turkey 6,500 BC
• 6,000 8,000 year old necklace in Anatolia
• Uses in Ancient Rome, Egypt and China
• Water pipes
• Lead Plumbum in Latin, Pb
• Plumbers, plumb bobs, plumb line
• Sewer pipes
• Face powders, mascaras, rouges
• Lining on copper pots for boiling syrups and
  wines
• Wine preservative
• Ceramic glazes

4
Historical Uses of Lead

• Uses in Medieval Era
• Lead acetate as sweetener in food
• Stained glass windows
• Seal gaps in stone blocks, framing roofs
• Moveable type for printing press
• Pewter, Bronze
• Lead coins
• Spermicide in informal birth control cold metal
  for chastity belts
• Paint
• Succession powder

5
Modern Uses of Lead

• Ammunitions and weaponry
• Octane-boosting gasoline additive
• Tetraethyl lead
• Paints
• Anti-radiation screens
• Lead weights in tires
• Solders and welding alloys
• Hobbies (fishing, hunting)
• By-product of mining and initial metal processing
• Silver, gold, bismuth

6
Symptoms

• Seizure, coma, death (acute high dose exposure)
• Neurological sequelae
• Decreased IQ, hyperactivity, irritability
• Gastrointestinal concerns
• Abdominal pain, vomiting, weight loss, poor
  appetite
• Behavioral modifications
• Lowered chance of finishing school
• Increased rates of delinquency, crime
• Renal and hematological (anemia) problems
• Reproductive problems

7
Defining Lead Poisoning
8
Lead Toxicity

• Once absorbedlead is mostly expelled (80), NOT
  metabolized
• Remaining portion settles into tissues (20)
• Erythrocytes (blood)
• Mineral tissues deposits (bone, teeth)
• Soft tissues (kidneys, bone marrow, liver, brain)

9
Mechanism of Toxicity

• Mimics calcium
• Stored in bones, becomes stable especially if
  insufficient Ca uptake
• Pb mobilizes under stress (pregnancy,
  breast-feeding, disease) or with increased Ca
  uptake
• Pb uptake through blood-brain barrier, mediated
  through Ca channels
• Pb interferes with normal Ca conduction through
  cells neurological

10
IQ as a function of blood lead levels
IQ
Blood Lead Level (ug/dL)
11
Incidence of Lead Poisoning
Lead banned in paint
12
Routes of Exposure

• Inhalation
• Ingestion
• Water
• Food (e.g., residues from cans, ceramics)
• Paint flakes and chips
• Dust (via renovations, friction of leaded paint)
• Soil (pica)
• Household remedies (e.g., azarcon)
• Foreign bodies

13
Costs of Lead Poisoning and Prevention
14
Lead Regulations

• 1978 EPA bans lead from paint
• 1980s FDA encourages elimination of lead
  soldered food and beverage containers
• from United States
• 1985 Phaseout of leaded gasoline
• 1988 EPA bans lead from use in household
• plumbing
• CDC Strategic Plan for the Elimination of
  Childhood Lead Exposure

15
Environmental Health Success

• Implicated lead exposure as causal agent for
  numerous human health outcomes
• Difficult for most environmental exposures
• Each agent has multiple health outcomes
• Multiple agents can cause single outcome
• Developed and implemented effort to prevent
  exposure

16
Environmental Justice

• High risk children
• Older homes
• Urban
• Impoverished
• Poor nutritional status
• Poor-quality housing stock in disrepair
• Renters vs. home owners
• Race and ethnicity
• Minorities with elevated incidence and severity

17
Environmental Justice

• Crawford County Household Lead Assessment
  project
• Incidence of lead poisoning in rural low-income
  communities project