lead exposures and health effects-slideshare
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Environmental Lead HazardsKevin Smith
Environmental Epidemiology
Spring 2015
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Major Sources and Distributions Lead Based Paint
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Major Sources and Distributions Lead Based Paint
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Major Sources and Distributions Lead Based Paint
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Major Sources and Distributions Lead Based Paint
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Major Sources and Distributions Lead Based Paint
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Major Sources and Distributions Lead Based Paint
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Major Sources and Distributions Lead Dust in Soil
Gasoline Emissions
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Major Sources and Distributions Lead Dust in Soil
Gasoline Emissions
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Major Sources and Distributions Lead Dust in Soil
Gasoline Emissions
Settles in urban soils
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Major Sources and Distributions Lead Dust in Soil
Gasoline Emissions
Settles in urban soils
Home Paint Runoff
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Sources and DistributionsOther 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
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Sources and Distributions Lead Based Paint:
~3 million metric tons (CDC, 1991)
24 million homes in USA (CDC, 2015)
Leaded Gasoline Emission:
5.56.7 million metric tons in soil (CDC, 1991)
75% remains
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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)
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Sources and Distributions
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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/
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How many People are Exposed? Approximately 535,000 children have elevated blood lead ( 5g/dL) (CDC, 2014)
Roughly, 9.5 million U.S. children: 2-10 g/dL (Gould, 2009)
Women childbearing age (20-49 years) (CDC, 2010)
2.5 g/dL: 30%
5 g/dL: 6%
10 g/dL:
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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%
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Who is Exposed? USA Children: 1 - 5 years old with BLLs 5 g/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
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Who is Exposed?
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Who is Exposed?
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Common Co-Pollutants
House dust may contain: (Roberts, 2009) Lead
Arsenic
Cadmium
Chromium
Phthalates
Allergens
Infectious bacteria
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Common Co-Pollutants Soil: (Dearwent, 2006)
Arsenic
Cadmium
Copper
Volatile Organic Compounds (VOCs)
Polychlorinated Biphenols (PCBs)
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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
Childrens toys
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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
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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
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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
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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
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Regulations & Exposure Limits Clean Air Act (1970):
Regulated air pollution from stationary and mobile sources
1978: EPA sets standard airborne emissions to 1.5g/m3
1990: Clean Air Act Amendment prohibited leaded gasoline
Starting 12/31/1995
1992: Motor vehicles requiring leaded gasoline were prohibited from the market
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Health Impacts Nervous System
Kidneys
Blood
Formation of cells
Anemia
Endocrine
Calcium homeostatsis
Tooth and bone development
Cardiovascular
Latent hypertension and heart disease
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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
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Health Impacts Reproduction
Reduced sperm count
Pregnancy
Preterm birth
Stillbirths
Child Development
Low birth weight
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Meeting with an Expert
City of Milwaukee Health Department Childhood Lead Poisoning Prevention Program Program Manager
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What is Unknown The health effect on adults is largely unknown
Small amount of research
Difficult to reproduce
Transgenerational effects are unknown Mothers 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
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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
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Article Review: Amato, 2013
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Article Review: Amato, 2013
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Article Review: Amato, 2013
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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?
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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 (
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