Environmental Risk Assessment Term Paper Shaaban Fundi May 10, 2004

A Review of the Effectiveness of Lead Abatement Strategies in Reducing Lead Exposure Among Children Environmental Risk Assessment Term Paper Shaaban Fundi May 10, 2004

Background • Lead is one of the most widely dispersed toxic substances in recent human history • Children have suffered and continue to suffer from lead exposure despite legislation to ban lead in gasoline and paint products in the 1970s • Even today, a large number of children continue to be exposed to unacceptably high levels of lead in their environment (>20μg/dL) • This is due to the fact that, lead is very stable element and once in the environment it can remain for decades

Recent trends of lead exposure to children • Lead exposure through industrial and gasoline emissions and through drinking water has declined in recent years • The exposure to lead in household dust and urban contaminated soil, however, has increased • Lead based paint is currently viewed as the predominant contributor to elevated blood lead levels (>10μg/dL) in U.S. children

Recent trends of lead exposure to children • Approximately 42 million homes in the United States contain lead based paint • About 12 million children under the age of 7 are exposed to lead paint each year even though the addition of lead to residential paint was banned in 1978 • 890,000 or 4.4% of U.S. children 5 years and younger have blood lead levels exceeding 10μg/dL, the level at which harmful affects are believed to occur

Interior Lead-Based Paint Exterior Solid Dust Interior Dust Community Sources Exterior Paint Child Hands, toys, food, and other mouthable objects Lead in Tap Water Pathways of lead exposure in children

Why are children more susceptible to lead poisoning? • Gastric absorption efficiency is greater in children • Normal play activities put them at greater risk of exposure to dust and soil • Children are more likely to put things in their mouth known as “pica behavior” thereby increasing the chance for ingestion • 6μg/day is considered safe intake level and may be exceeded by children who play in outdoor environments contaminated with lead

Heath effects of lead to children • Lead exposure is linked to several health problem in young children • Behavioral affects of lead exposure includes cognitive deficits, behavioral disorders, and propensity towards violence • Biological affects ranges in severity depending to level of exposure and includes slow growth, impaired hearing and reduction in hand to eye coordination • At very high levels(>100μg/dL), lead can cause coma, convulsion and finally death

Legend: Factors leading to lead exposure Dust and Paint Abatement Housing: --pre-1950 housing --pre-1978 paints Interventions to mitigate lead exposure Health Effects: --Low cognitive function --Neurobehavioral deficit --Impaired growth --Hearing problems --Severe stomach cramps --Impaired nerve function Soil Abatement Demographics: --Race/Ethnicity -Socioeconomic Status --Child’s Age --Parent’s Income --Parent’s Education Level --Place of Residence Elevated Blood Lead Levels in Children Soil Contamination: --Lead in soil/lawns --Lead in paint chips --Car emissions Chelation Drinking Water: --Lead in pipes/solder Monitoring of Tap Water for Lead

Lead Abatement Strategies:Soil Abatement • Soil abatement---usually consist of removing 6 inches of top soil and covering it with clean soil and ground cover • It is recommended for those area with lead concentration in soil >500ppm • The cost of intervention is around $9600 per property abated

Lead Abatement Strategies:Reducing Exposure In Drinking Water • Lead is reduced in water by replacing lead containing pipes or by treating supplied water to reduce its corrosiveness • The EPA requires all public water systems to monitor their tap water for excessive lead concentrations (defined as >15g/L) • These regulations have greatly reduced the exposure of lead through tap water

Lead Abatement Strategies:Residential Paint Abatement • Lead paint abatement involves removing or covering lead paint from accessible surfaces 5 feet or less from ground and removing or covering exterior paint • Is recommended for homes with lead levels of 100μg/ft2, 500 μg/ft2, 800 μg/ft2 for floors, interior window sills and window troughs respectively • The average cost for this procedure is $9000 per unit

Lead Abatement Strategies:Dust Abatement • Interior dust abatement consists of vacuuming walls, woodwork, floors and rugs with high efficiency filter vacuum (HEPA) and wiping surfaces with wet cloth and furniture with oil treated cloths • Interior loose paint stabilization is done by HEPA vacuuming and washing areas of loose paint on walls and woodwork with trisodium phoshate and painting window wells with primer • The average cost of this type intervention is $4500/unit

Rationale of this study • Despite the overwhelming interest in these abatement procedures there have been few attempts to systematically review the strength of evidence for the effectiveness of these interventions at reducing blood lead levels in children • This study reviews the current information on residential lead abatement strategies in order to determine whether these abatement strategies are an effective method to prevent lead exposure in children as measured by blood lead levels • The question of interest for this study is: “Which lead abatement strategies are successful in reducing children’s exposure to lead?”

Methodology (Search Strategy) • Articles published between January 1990 and March 2004 were reviewed • Articles were identified through a comprehensive search of three electronic databases: Pubmed, the National Library of Medicine’s Gateway, and Lexis Nexis • Unpublished documents were obtained through searching several websites including the Environmental Protection Agency, the Centers for Disease Control website, and the Department of Health Services website • The search terms used during the computer based searches were: residential lead abatement strategies; lead exposure and children; lead abatement and children; and lead exposure and policies

Methodology (Inclusion Criteria) • To be eligible for this review the studies must have met the following criteria • Included children less than 6 years of age • Been conducted and published in the United States between 1990 and 2004 • Have either a pre/post or multi-arm study design • Assessed the effect of lead abatement strategy on children’s blood lead levels

Overview of Articles Found • Of the 136 articles located through electronic searching and secondary searching, 19 studies met the inclusion criteria • 15 of the 19 studies were conducted in the northeast (New York, Maryland, New jersey, and Massachusetts), 3 were conducted in the central part of the country (Wisconsin, Missouri, and Utah); and the final study was conducted in multiple settings including Cincinnati, Newark, Baltimore, and Philadelphia • 18 of the studies were conducted in urban areas and only 1 study was conducted in a rural area

Overview of Articles Found • The selected studies varied greatly in terms of their sample size, study design, and methods of data collection • 9 of the 19 studies had a randomized study design with both an intervention and control group • 6 studies used a pre/post study design with no control group • 2 studies used a retrospective study design and the last 2 studies had a non randomized multi-arm study design with and intervention and a control group

Study Classification • Of the 19 studies that met the inclusion criteria • 3 studies looked at soil abatement, 10 studies looked at dust abatement, and 2 studies looked at a mixture of soil and dust abatement • No studies looking at the effect of monitoring tap water for lead on children’s lead exposure were identified in this review

Results (Soil Abatement) • Three studies looked at the effectiveness of soil abatement • Two studies showed a significant reduction in children’s blood lead levels (Weitzman et al., and Lanphear et al.) • One study showed no significant change (Farrell et al.)

Results (Soil Abatement) • Soil abatement appears to have mixed results in reducing children’s blood lead levels • It appears to be more effective in children whose primary exposure to lead is through contaminated soil and not dust or lead paint • In addition, it appears to be more effective in areas where the soil lead concentration is very high (>1000ppm)

Results (Paint Abatement) • 4 studies looked at the effectiveness of paint abatement • 3 studies, 2 conducted in Baltimore and 1 in Boston showed non significant results (Farfel et al., and Amitai et al.) • 1 study conducted in St. Louis, Missouri showed a significant decrease in children’s blood lead level (Staes et al.)

Results (Paint Abatement) • Paint abatement strategies appears to be more effective with children who have high blood lead levels(>25µg/dL) • Amitai and colleagues found that blood lead levels actually went up during deleading using heat guns or propane lead abatement and that methods of deleading are an important factor in determining how high blood lead levels rose in children • Therefore, caution should be taken when choosing the method of paint abatement as some methods cause substantial increase in children’s blood lead levels during the abatement process

Results (Dust Abatement) • 10 studies looked at the effectiveness of dust abatement • 4 studies showed a statistically significant reduction in children’s blood lead levels (Rhoads et al.) • 6 studies reported no significant results (Shultz et al., Yiin et al., and Lanphear et. al.)

Results (Dust Abatement) • Studies show that professional cleaning is an effective strategy to reduce household lead dust • In order to maximize professional cleaning effectiveness, cleaning must be repeated every 2-3 weeks to prevent dust re-accumulation • In addition, carpets and upholstery appears not to be effectively cleaned by HEPA vacuuming and remain important source of lead exposure to children

Results (Multiple Pathway Abatement) • Soil abatement combined with lead paint abatement has shown to reduce blood lead levels in children in the short term (0-3 months) • Multiple pathway abatement has failed to reduce children blood lead levels over the long term (over 9 months) • The researchers suggests that greater emphasis be placed on primary intervention by abating home before occupancy to prevent lead exposure to children in the first place

Conclusion • The evidence for residential lead abatement strategies is mixed with some studies showing high efficacy and some showing no change in children’s blood lead levels post abatement • On the basis of the current review it is not possible to say with certainty which methods of lead abatement are more effective • More research with good study design needs to be undertaken before intervention with proven effectiveness can be identified • It is essential that this research be done in order to prevent the life long effects of lead poisoning in children

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Environmental Risk Assessment Term Paper Shaaban Fundi May 10, 2004