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Findings

Families who participated in the investigation received their individual child’s or children’s blood lead results in the summer of 2014 (results were mailed out within two weeks of the child’s blood sample collection). Families who participated in the investigation received their individual environmental sampling results by mail in December 2014. At this time, ATSDR/CDC is now able to share preliminary summary blood lead and environmental results from this investigation. Further analysis is continuing now. Later this summer or early fall, we plan to share what these summary statistics mean for this community and other communities with urban lead contamination.

Children blood lead levels

  • One hundred twenty-six eligible children with blood lead data from 82 unique households make up the investigation’s data set for blood lead analysis. Of the 126 blood lead samples in the overall data set, 95 results came from children aged 9 through 71 months who provided blood samples at the time of the investigation, and 31 results came from children aged 9 through 71 months enrolled in the investigation who did not provide blood samples at the time of the investigation but who had prior blood tests recorded in PDPH’s surveillance system.
  • One child (0.8%) had a blood lead level equal or above (≥) 10 micrograms per deciliter (µg/dL), and 14 children (11.1%) had blood lead levels ≥ 5 µg/dL (including the child with blood lead level of 10 µg/dL or above). The percentage of children with an elevated blood lead level result may be as high as 13%. Estimates vary with different children’s age ranges included in the calculation.
  • The geometric mean for the 126 blood lead samples in this investigation is 1.96 µg/dL (95% confidence interval (CI) of 1.7-2.26). The geometric mean blood lead level of children aged 1-5 years from NHANES 2007-2010 is 1.3 ug/dL (95% CI 1.3-1.4) (https://www.cdc.gov/mmwr/preview/mmwrhtml/mm6213a3.htm). The investigation blood lead data is log normally distributed.
  • The estimated percentage of children aged 1–5 years with blood lead levels ≥5 µg/dL for the 126 blood lead samples is 11.1%. The estimated percentage of children aged 1–5 years with blood lead levels ≥5 µg/dL from NHANES 2007-2010 is 2.6%.
  • PDPH uses a reference blood lead value of 10 µg/dL to initiate follow up of children. In 2012, CDC/ATSDR began using a reference value of 5 µg/dL based on 97.5% of the distribution of blood lead levels in children 1-5 years of age in NHANES 2007-2010. At the time of this investigation, the CDC/ATSDR reference value for elevated blood lead levels for children 1-5 years old was 5 µg/dL.
  • The maximum blood lead level in the investigation was 11 µg/dL. The second highest blood lead level was 9.8 µg/dL. For the purposes of offering healthy homes services and case management follow up, PDPH rounded the second highest blood lead level to 10 µg/dL and offered follow up services and education to this family in addition to the child with the maximum value of 11 µg/dL. All families who participated in the study were provided information about lead hazards and mitigating their families’ exposures to lead.

Tap water

  • 120 tap water samples were collected from participants’ kitchen sinks. Lead concentration ranged from non-detectable to 3.9 μg/L.
  • EPA’s action level for lead in water (15 μg/L) was used. No lead levels were elevated above EPA’s action level in tap water samples. EPA’s Maximum Contaminant Level Goal (MCLG) for lead is zero. Twenty-two of the 120 tap water samples had detectable levels of lead.

Dust wipes

  • Dust wipe samples were collected from each participating household. Dust wipes were collected from the floor in the house entryway, the floor in the child’s play area, and the window sill in the child’s room. EPA states that floors with lead levels of 40 micrograms per square foot (g/ft2) or greater and window sills with levels of 250 μg/ft2 or greater are lead hazards (http://www2.epa.gov/lead/hazard-standards-lead-paint-dust-and-soil-tsca-section-403).
  • Of 119 indoor dust floor samples from household entryways, elevated lead levels were found in 26 samples (22%). Lead concentration ranged from non-detectable to 2,300 μg/ft2.
  • Of 106 indoor dust floor sample from the child’s play area, elevated levels were found in 21 samples (18%). Lead concentration ranged from non-detectable to 630 μg/ft2.
  • Of 108 indoor dust window samples from the window sill in the child’s room, elevated levels were found in 13 samples (12%). Lead concentration ranged from non-detectable to 18,000 μg/ft2.

Soil samples

  • Soil samples were collected from participant’s yards in areas identified as the child’s outdoor play area. Soil samples were collected and characterized according to EPA methods SW-3050B, SW-6020A and Prep-3010a. EPA guidance is evolving but suggests that a soil-lead hazard is present when bare soil contains total lead equal to or exceeding 400 ppm in a play area.
  • Of the 72 soil samples, lead levels above 400 ppm were found in 51 samples (71%). Soil lead results ranged from 40 ppm to 7,700 ppm.

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