lead exposures and health effects-slideshare

Environmental Lead HazardsKevin Smith

Environmental Epidemiology

Spring 2015

Major Sources and Distributions Lead Based Paint

Major Sources and Distributions Lead Dust in Soil

Gasoline Emissions


Gasoline Emissions

Settles in urban soils


Gasoline Emissions

Settles in urban soils

Home Paint Runoff

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

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

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)


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/

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:

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%

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

Who is Exposed?

Common Co-Pollutants

House dust may contain: (Roberts, 2009) Lead

Arsenic

Cadmium

Chromium

Phthalates

Allergens

Infectious bacteria

Common Co-Pollutants Soil: (Dearwent, 2006)

Arsenic

Cadmium

Copper

Volatile Organic Compounds (VOCs)

Polychlorinated Biphenols (PCBs)

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

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

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

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

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

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

Health Impacts Nervous System

Kidneys

Blood

Formation of cells

Anemia

Endocrine

Calcium homeostatsis

Tooth and bone development

Cardiovascular

Latent hypertension and heart disease

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

Health Impacts Reproduction

Reduced sperm count

Pregnancy

Preterm birth

Stillbirths

Child Development

Low birth weight

Meeting with an Expert

City of Milwaukee Health Department Childhood Lead Poisoning Prevention Program Program Manager

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

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

Article Review: Amato, 2013

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?

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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