This document discusses environmental lead hazards and exposures. It covers major sources of lead like lead-based paint and leaded gasoline emissions which have deposited lead in soils. Children under 6, minorities, and those below the poverty line are most at risk of exposure through ingesting lead paint chips/dust or contaminated soils. Exposure can cause neurological, cardiovascular and learning impairments. Regulations have reduced lead in gasoline and paint but ongoing monitoring and funding is still needed to address remaining hazards.

1. Environmental Lead
Hazards
Kevin Smith
Environmental Epidemiology
Spring 2015

2. Major Sources and Distributions
• Lead Based Paint

3. Major Sources and Distributions
• Lead Based Paint

4. Major Sources and Distributions
• Lead Based Paint

5. Major Sources and Distributions
• Lead Based Paint

6. Major Sources and Distributions
• Lead Based Paint

7. Major Sources and Distributions
• Lead Based Paint

8. Major Sources and Distributions
• Lead Dust in Soil
 Gasoline Emissions

9. Major Sources and Distributions
• Lead Dust in Soil
 Gasoline Emissions

10. Major Sources and Distributions
• Lead Dust in Soil
 Gasoline Emissions
 Settles in urban soils

11. Major Sources and Distributions
• Lead Dust in Soil
 Gasoline Emissions
 Settles in urban soils
 Home Paint Runoff

12. Sources and Distributions
Other sources of exposure (CDC, 2014)
 Lead in Drinking Water – Lead Pipes
 Industrial Air Pollutants
 Lead Dust on Work Clothes
 Other cosmetics, pottery glaze, toys and playground equipment

13. Sources and Distributions
• Lead Based Paint:
 ~3 million metric tons (CDC,
1991)
 24 million homes in USA
(CDC, 2015)
• Leaded Gasoline Emission:
 5.5–6.7 million metric tons
in soil (CDC, 1991)
 75% remains

14. Sources and Distributions
• Homes built before 1978 have
lead based paint (HUD, 2011)
 Before 1940*
• Nearly 4 million homes with
children living in them have lead
based paint (CDC, 2014)

15. Sources and Distributions

16. Sources and Distributions
• Soils of metropolitan areas
(Mielke, 2010)
 14.1% of pre1940 housing >1200
ppm
 1% of post-1960 housing >1200
ppm
 Inner city
 Increased traffic
 Low income areas
http://www.usgs.gov/blogs/features/usgs_top_story/getting-the-dirt-on-soil/

17. How many People are Exposed?
• Approximately 535,000 children have elevated blood lead (≥ 5μg/dL) (CDC, 2014)
• Roughly, 9.5 million U.S. children: 2-10 μg/dL (Gould, 2009)
• Women childbearing age (20-49 years) (CDC, 2010)
 ≥ 2.5 μg/dL: 30%
 ≥ 5 μg/dL: 6%
 ≥ 10 μg/dL: <1%

18. Who is Exposed?
• US sub-populations exposed to lead based paint:
 Age:
 36 months and less are at greatest risk
 72 months and younger
 Race (HUD, 2011) :
 African American: 45.3%
 Other Race: 49.3%
 White non-Hispanic: 31.6%
 Income (HUD, 2011) :
 < $30,000: 35%
 > $30,000: 18%

19. Who is Exposed?
• USA Children: 1 - 5 years old with BLLs ≥ 5 μg/dL (Wheeler, 2013):
 Age:
 1-2 years old: 3.1%
 3-5 years old: 2.3%
 Race:
 non-Hispanic Black: 5.6%
 White non-Hispanic: 2.4%
 Mexican-American: 1.9%
 Income (poverty-to-income ratio):
 Poverty-to-income ratio <1.3: 4.4%
 Poverty-to-income ratio ≥ 1.3: 1.2%

20. Who is Exposed?

21. Who is Exposed?

22. Common Co-Pollutants
 House dust may contain: (Roberts, 2009)
 Lead
 Arsenic
 Cadmium
 Chromium
 Phthalates
 Allergens
 Infectious bacteria

23. Common Co-Pollutants
• Soil: (Dearwent, 2006)
 Arsenic
 Cadmium
 Copper
 Volatile Organic Compounds (VOCs)
 Polychlorinated Biphenols (PCBs)

24. Routes of Exposure
• Inhalation
 Dust
 Soil
 Air pollution
 Vehicle exhaust
 Industrial air pollution
 Occupational hazards
 Adult hazards
 Exposure to children of workers
• Ingestion:
 Paint chips and dust
 Soil dust
 Contaminated water
 Fruits and vegetables in urban gardens
 Children’s toys

25. Mechanism of Action
• Physiology
 Lead mimics calcium in the body
 Neurons
 Bones and teeth
 Interfere with kidney function
 Acute high dose
 May be reversible
 Chronic low dose
 Irreversible
 Blood
 Anemia
 Lead can also interact with proteins and enzymes

26. How is Exposure Measured?
• What are best methods?
 Blood Lead Levels (BLLs) – Direct measurement
 Capillary
 Venous
 Protoporphyrin Levels – Measurement of Acute vs. Chronic
 Erythrocyte Protoporphyrin (EPP)
 Zinc Protoporphyrin (ZPP)
 X-Ray techniques
 Bones
 Teeth

27. How is Exposure Measured?
• Improvements
 BLLs are very accurate
 Capillary false positive from lead on skin
 Protoporphyrin measurement is very accurate
 X-Ray technique is less common

28. Regulations & Exposure Limits
• Lead Based Paint Poisoning Prevention Act (1971):
 Prohibit lead-based paint in residential structures
 Defined lead-based paint as ≥ 1% lead by weight
 1973: Amendment
 Mandated HUD elimination of pre-1950s home paint
 Allowable levels
 0.5% until 12/31/1974
 0.06% (600 ppm) after 12/31/1974
 1978: Consumer Product Safety Commission
 Banned residential use of lead paint ≥ 0.06% or 600ppm

29. Regulations & Exposure Limits
• Clean Air Act (1970):
 Regulated air pollution from stationary and mobile sources
 1978: EPA sets standard airborne emissions to 1.5μg/m3
 1990: Clean Air Act Amendment prohibited leaded gasoline
 Starting 12/31/1995
 1992: Motor vehicles requiring leaded gasoline were prohibited from the
market

30. Health Impacts
• Nervous System
• Kidneys
• Blood
 Formation of cells
 Anemia
• Endocrine
 Calcium homeostatsis
 Tooth and bone development
• Cardiovascular
 Latent hypertension and heart
disease

31. Health Impacts
• Learning Impairments
 4th grade standardized tests (Amato, 2012)
 Reading
 Mathematics
 Language Arts
• Behavioral Impairments
 4th grade suspension rates (Amato, 2013)
 2.66 times more likely
 23% of the racial discipline gap
 Crime (Mielke, 2012)
 Aggravated assault – 22 year lag time

32. Health Impacts
• Reproduction
 Reduced sperm count
• Pregnancy
 Preterm birth
 Stillbirths
• Child Development
 Low birth weight

33. Meeting with an Expert
 City of Milwaukee Health Department –
Childhood Lead Poisoning Prevention Program –
Program Manager

34. What is Unknown
• The health effect on adults is largely unknown
 Small amount of research
 Difficult to reproduce
• Transgenerational effects are unknown
 Mother’s lead stores in the bone - developing fetus
• Childhood exposure and learning & behavior effects
 Not well developed
 Brain development
 What is causing the learning & behavior deficits
• Other effects on the quality of life
 IQ and decreased earning over the life time
 Poverty
 Housing displacement

35. Recommended Improvements in
Public Health
• Abatement requires continual effort
 New paint deteriorates - lead hazards become exposed
• Federal Funding
 In 2013, cut from $29 million to $2 million per year
 Currently rely in state funding, grant money and donations
• Preparedness for Other Environmental Sources
 Water main bursts may contaminate sewer systems
 Natural Disasters
 Lead Mines

36. Article Review: Amato, 2013

37. Article Review: Amato, 2013

38. Article Review: Amato, 2013

39. Article Review: Amato, 2013
• Did the investigator use the correct measure of association?
 Odds Ratio vs Relative Risk
• Were all confounders accounted for or could there be others?
 Socioeconomic Status
 Current Level of Poverty in the Neighborhood
 Quality of the School System amplified effects?
• What Conclusions could be drawn from this study?
• What could the Education System do the assist these children?

40. References
• Amato, M.S., Moor, C.F., Magzamen, S., Imm, P., Havlena, J.A., Anderson, H.A., and Kanarek, M.S. (2012). Lead exposure and
educational proficiency on end-of-grade examinations. Annals of Epidemiology, 22(10), 738-743.
• Amato, M.S., Magzamen, S., Imm, P., Havlena, J.A., Anderson, H.A., Kanarek, M.S., and Moore, C.F. (2013). Early lead exposure (<3
years old) prospectively predicts fourth grade school suspension in Milwaukee, Wisconsin (USA). Environmental Research, 126, 60-65.
• Center for Disease Control and Prevention (1991, October 1). Preventing Lead Poisoning in Young Children: Chapter 3. Retrieved from:
http://www.cdc.gov/nceh/lead/Publications/books/plpyc/chapter3.htm
• Center for Disease Control and Prevention (2014, June 19). Lead – Home Page. Retrieved from: http://www.cdc.gov/nceh/lead/
• Center for Disease Control and Prevention (2014, October 30). LCDC’s national Surveillance Data (1997-2013). Retrieved from:
http://www.cdc.gov/nceh/lead/data/national.htm
• Cox, D.C., Dewalt, G., O’Haver, R., and Salatino, B. American Health Homes Survey; Lead and Arsenic Findings. U.S. Department of
Housing and Urban Development: Office of Healthy Homes and Lead Hazard Control, April, 2011.Mielke, 2010
• Dearwent, S.M., Mumtaz, M.M., Godfrey, G., Sinks, T., and Falk, H. (2006). Health Effects of Hazardous Waste. Annals New York
Academy of Sciences, 1076; 439-448 Amato, M.S., Moor, C.F., Magzamen, S., Imm, P., Havlena, J.A., Anderson, H.A., and Kanarek, M.S.
(2012). Lead exposure and educational proficiency on end-of-grade examinations. Annals of Epidemiology, 22(10), 738-743.
• Gould, E. (2009). Childhood Lead Poisoning: Conservative Estimates of the Social and Economic Benefits of Lead Hazard Contro l.
Environmental Health Perspectives, 117, (7), 1162 - 1167
• Mielke, H.W. and Zahran, S. (2012). The urban rise and fall of air lead (Pb) and the latent surge and retreat of societal violence.
Environmental International, 43, 48-55.
• Wheeler, W. (2013). Blood Lead Levels in Children Aged 1-5 Years – United States, 1999-2010. Morbidity and Mortality Weekly Report,
62, (13), 245-248.Roberts, 2009