environmental lead (pb) sources and exposure pathways to children in urban areas ray w. brown 1,...

Environmental lead (Pb) sources and exposure pathways to children in urban areas

Ray W. Brown1, Chris Gonzales2, Andrew C. Bayat3, Ashley M. Fornerette4, Tobias J. McBride1, Michael J. Hooper1, Thomas Longoria5, Howard W. Mielke6

1Department of Environmental Toxicology, The Institute of Environmental and Human Health, Texas Tech University; 2College of Pharmacy, Xavier University of Louisiana; 3Biology Department, Austin College, Sherman,

Texas; 4Department of Biology, Xavier University of Louisiana,; 5Center for Public Service, Texas Tech University,, 6Center for Bioenvironmental

Research, Tulane University

Presented to the Air and Waste Management Association

High Plains Chapter November 1st, 2007

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The whole history of civilization is strewn with creeds and institutions which were invaluable at first, and deadly afterwards.

– Walter Bagehot English economist & journalist (1826 - 1877)

Measurement of Pb through the atmosphere (108g/yr)

Natural AnthropogenicContinental Dust

Volcanic Dust

Volcanic Gas

Industrial Particles

Fossil Fuel

Ratio:

Anthropogenic/

natural

50 8.7 0.012 16,000 4,300 345.83

Lantzy, R. J. & Mackenzie, F. T. (1979). Atmospheric trace metals: Global cycles and assessment of man's impact. Geochimica et Cosmochimica Acta, 43, 511-525

• Old paint on homes (pre-1980)• Lead dust in the carpet• Lead solder in joints• Old bathtubs (metal)• Marine paint• Yellow stripes in roads• Industrial Metals• Lead putty in windows• Brass candle sticks• Old knife sharpeners• Vinyl roll-up Venetian blinds• Bullets• Fishing sinkers• Pool cue chalk• Simulated pearls (coating has

lead)• Some Cosmetics• Canned foods (imported): weld

contains lead• Candy wrappers

• Hobbies– artist paint– photography chemicals– stained glass– enamel, bronze or brass

plating• Colored newspaper print (comics)• Hair dyes• Culturally-specific products

– (Azarcon: Coral, Rueda, Maria Luisa), Greta, Albayalde, Pay-loo-ah, Xyuuaj Fab, Tsuaj gais nyiaj, Ghassard, Bala Goli, Kandu, Kohl (Alkohl)

• Metal toys or toys with metal paint (wash toys and pacifiers frequently)

• Dishes (imported, handmade, bright colored pottery)

• Clothes (if a parent works around lead, he/she can bring lead home on clothing)

• Costume jewelry (many brands) especially those made outside the U.S.

• Candles with a metallic core• Some insecticides

Lots of potential Pb Sources

Most everyone is aware thatPb is a poison.

• Question 1: What is the primary source of Pb to children?

– Pb-based paint.

• Question 2: How might we assess potential risk to children in a

community like Lubbock?

– Determine the age of housing where children live

Age of housing is not correlated with

children’s blood Pb levels in many

urban environments that have been

studied so far.

Adapted from: Mielke HW, Reagan PL. 1998. Soil Is an Important Pathway of Human Lead Exposure. Environmental Health Perspectives Supplements 106:217.

%

Some Factors that have been correlated with children’s blood

Pb levels

• Proximity to high traffic areas

• Use of hot water

• Use of leaded personal products

• Season (summer vs. fall)

Exposure to Exterior Soils Indoors

• Exterior soil accounts for 31% of interior dust

• Children ingest 9-40 mg/soil/day

Calabrese et al. Reg Tox & Pharm 1989;10:123-137

Dust, Soil, Blood Lead Dust, Soil, Blood Lead RelationshipsRelationships

2040

55

100

5001000

2000

0%

10%

20%

30%

40%

50%

Lanphear et al. Env Research 1998;79:51-68

Interior dust lead loading, g/ft

Soil/exterior lead, ppm

% with BLL 10

g/dL

• The source of Pb in 70% of gardens studied in Massachusetts was a mixture of paint and gasoline.

• The maximum average contribution of interior paint to floor and window sill Pb was 50%

• In determination of sources of interior dust Pb, exterior sources contributed as much as or more than interior lead-based paints.

Adgate, J. L., Rhoads, G. G. & Lioy, P. J. (1998). The use of isotope ratios to apportion sources of lead in Jersey City, NJ, house dust wipe samples. Science of the Total Environment, 221, 171-180

Clark, H. F., Brabander, D. J. & Erdil, R. M. (2006). Sources, sinks, and exposure pathways of lead in urban garden soil. Journal of environmental quality, 35, 2066-2074

“Soils are the best indicator of potential Pb exposure (e.g. as opposed to age of housing) since they integrate not only exposure from lead-based paints, but also other sources (incinerators, Pb-added gasoline, other wastes).”

Mielke HW, Reagan PL. 1998. Soil Is an Important Pathway of Human Lead Exposure. Environmental Health Perspectives Supplements 106:217.

Pb Concentrations of ConcernSoil

400 mg/kg = hazard in children’s play area

1200 mg/kg = hazard for the rest of the yard

- 40 CFR Part 745, Lead; Identification of Dangerous Levels of Lead; Final Rule

310 mg/kg = soil concentration predicted to result in child blood level of 9 g/dL

- Mielke, H. W. & Reagan, P. L. (1998). Soil is an important pathway of human lead exposure. Environmental Health Perspectives Supplements, 106: 217-229

A concentration of 80 ppm in soils may

provide a margin of safety for children

given that median blood lead levels in this

range are 6.0 g/dL.

Jones, C., Elert, M., and Christiansson, A. 1998. Fördjupad miljöoch hälsoriskbedömning avsende Falu Tätort. Kemakta Konsult AB, Falu kommun. 51 pp.

Mielke HW, Gonzales CR, Smith MK, Mielke PW. 1999. The urban environment and children's health: Soils as an integrator of lead, zinc, and cadmium in New Orleans, Louisiana, USA. Environmental Research 81(2):117-129.

Pb Concentrations of Concern

Children’s Blood

> 10 g/dL = lead poisoning

-National Center for Environmental Health/Centers for

Disease Control & Prevention

> 5 g/dL = neurotoxicity in children- Canfield et al. 2003, Min et al. 2006

Canfield RL, Henderson CR, Cory-Slechta DA, Cox C, Jusko TA, Lanphear BP. 2003. Intellectual impairment in children with blood lead concentrations below 10 g per deciliter. New England Journal of Medicine 348(16):1517-1526.

“There is now sufficient and compelling

scientific evidence for the CDC to lower

the blood lead action level in children.

…no threshold for the health effects of lead

is demonstrable …(although) a blood level

of 2 g/dL provides a benchmark for

successful prevention.”

Gilbert, SG, Weiss B. 2006. A rationale for lowering the blood lead action level from 10 to 2 g/dL. NeuroToxicology. 27: 693-701.

Mielke HW, Gonzales CR, Smith MK, Mielke PW. 1999. The urban environment and children's health:Soils as an integrator of lead, zinc, and cadmium in New Orleans, Louisiana, USA. Environmental Research 81(2):117-129.Mielke HW, Powell ET, Gonzales CR, Mielke PW, Ottesen RT, Langedal M. 2006. New Orleans soil lead (Pb) cleanup using Mississippi River alluvium: Need, feasibility, and cost. Environmental Science & Technology 40(8):2784-2789

Prior to Hurricane Katrina, “20-30% of inner-city children had elevated blood Pb levels” in the high risk area

West Texas Lead Study

• A comprehensive assessment of Lubbock area soil contamination in

concert with an assessment of housing with Pb-based paint.

• Assessment of blood Pb concentrations in populations at risk.

• A determination of child populations at risk from exposure to Pb-based

paint, Pb-contaminated soil and/or other risk factors.

• Immediate implementation of simple steps parents and educators can take

to reduce Pb exposure to children in at-risk populations.

• Education of all citizens of Lubbock on both short-term and long-term

solutions to reduce exposure of all Lubbock children to Pb in their

environments.

West Texas Lead Study

• A comprehensive assessment of Lubbock area soil contamination in concert with an assessment of housing with Pb-based paint.

• Assessment of blood Pb concentrations in populations at risk.

• A determination of child populations at risk from exposure to Pb-based paint,

Pb-contaminated soil and/or other risk factors.

• Immediate implementation of simple steps parents and educators can take to

reduce Pb exposure to children in at-risk populations.

• Education of all citizens of Lubbock on both short-term and long-term solutions

to reduce exposure of all Lubbock children to Pb in their environments.

~ 1930

~ 1950

~ 1970

Lubbock, Texas, USALubbock, Texas, USA

0 2 4 6 8 10

0

20

40

60

80

100

Distance from Origin (km)

[Soil Pb] (mg Pb / kg Soil)

[Soil Pb] = 96.75e-0.212 * Distance

R2 = 0.7161, P < 0.0001

Lubbock, Texas, USALubbock, Texas, USA

So

il P

b C

on

cen

trat

ion

(m

g/k

g)

Distance from Origin (km)

[Soil Pb] (mg Pb / kg Soil)

0 2 4 6 8 10 12 14

0

25

50

75

100

125

150

175

[Soil Pb] = 151.2e-0.723 * Distance

R2 = 0.3592, P = 0.030

So

il P

b C

on

cen

trat

ion

(m

g/k

g)

Lubbock, Texas, USALubbock, Texas, USA

Lubbock, Texas, USALubbock, Texas, USA

Distance from Origin (km)

[Soil Pb] (mg Pb / kg Soil)

Distance from Origin (km)

0 1 2 3 4 5 6 7

0

20

40

60

80

100

[Soil Pb] = 91.90e-0.320 * Distance

R2 = 0.8363, P < 0.0001

So

il P

b C

on

cen

trat

ion

(m

g/k

g)

Soil Lead Concentrations in Census Tract 15.01 (Tech Terrace, Lubbock, TX)

0

100

200

300

400

500

600

700

800

Tech Terrace Soil Lead Sample TypesSoil Lead Concentrations (mg/kg)

Residential RoadsideHouse DriplineBusy Street RoadsideOpen Area

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West Texas Lead Study

• A comprehensive assessment of Lubbock area soil contamination in concert

with an assessment of housing with Pb-based paint.

• Assessment of blood Pb concentrations in populations at risk.

• A determination of child populations at risk from exposure to Pb-based paint,

Pb-contaminated soil and/or other risk factors.

• Immediate implementation of simple steps parents and educators can take to

reduce Pb exposure to children in at-risk populations.

• Education of all citizens of Lubbock on both short-term and long-term solutions

to reduce exposure of all Lubbock children to Pb in their environments.

Demographics & Blood Lead Data

Under Age 5 (2000) - 14,272

Births– 2001 - 3,826– 2002 - 3,947– 2003 - 4,064– 2004 - 4,049

Blood Lead Data Reported for Children Under Age 5

– 2000 - 884– 2001 - 729– 2002 - 921– 2003 - 1,155– 2004 - 1,112– 2005 - 1,017

Percent Children Tested

– 2000 - 6.2%– 2001 - 5.1%– 2002 - 6.4%– 2003 - 8.1%– 2004 - 7.8%– 2005 - 7.1%

Blood Lead Data for Children Ages 0 - 3

Zip Code Ranking # Tested # > 5 ug/dL % > 5 ug/dL

79403 1 435 180 41.479415 2 423 122 28.879404 3 451 119 26.479401 4 382 102 26.779412 5 417 97 23.379411 6 493 96 19.579413 7 493 48 9.779407 8 355 49 13.879416 9 498 47 9.479414 10 506 46 9.179423 11 377 42 11.179410 12 255 17 6.779424 13 190 15 7.9

79404

79401

79415

79411

79412

794037941579404794017941279411

79403

79404

79403

79401

79415

79411

79412

Hypotheses:Blood Pb concentrations are a function of age of housing

Blood Pb concentrations are a function of culturally-specific behaviors

Blood Pb concentrations are a function of geography

“…you will observe with concern how long a useful truth may be known and exist, before it is generally received and practiced on”

Benjamin Franklin’s recollections from his boyhood on the prohibition of the use of lead in rum production, causing people to lose the use of their hands

Project Supporters/Partners• Texas Tech University

– The Institute of Environmental and Human Health (TIEHH)– Center for Public Service– Honors College– Child Development Research Center– Department of Psychology– Department of Human Sciences– Department of Mass Communications

• TTUHSC Department of Pediatrics• TTUHSC School of Nursing• University of Texas - Arlington• UT Austin School of Nursing• Success by 6/United Way• Lubbock Housing Authority• Lubbock Independent School District

– Early Childhood Intervention/Early Childhood Intervention Developmental Education Birth to 3 (ECI/DEBT)

– LISD Early Head Start• Faith-based Organizations

– St. John’s UMC– Covenant Presbyterian Church