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