A Spatial Analysis of Geologic Conditions and Radon Risk

Stephanie Foster, David Yeomans, Julia Bryant, Efomo Woghiren, Brian Lewis, Andrew Dent

5th International Conference of Medical Geology27 August 2013

Agency for Toxic Substances and Disease RegistryDivision of Toxicology and Human Health Sciences

Geospatial Research, Analysis, and Services Program (GRASP)

Presentation Overview

Project Background Problem Statement Data and Methods Preliminary Results Next Steps

BACKGROUND

4

1

Deaths per Year, United States

2,800 3,900

17,400

3,000

21,000

US EPA 2003 Assessment of Risks from Radon in HomesCDC 2005-2006 National Center for Injury Prevention and Control Report

0.4 1.3 2 4 8 100

20

40

60

80

100

120

140

160

320

32

62

120

150

18

SmokerNever Smoked

Lifetime Radon Exposure (pCi/L)

Risk

of C

ance

r (p

er 1

,000

pe

ople

)Risk of Lung Cancer from Radon Exposure (per 1,000)

US EPA 2003 Assessment of Risks from Radon in Homes

0.4 1.3 2 4 8 100

20

40

60

80

100

120

140

160

3

20

32

62

120

150

2 4 715 18

SmokerNever Smoked

Lifetime Radon Exposure (pCi/L)

Risk

of C

ance

r (p

er 1

,000

pe

ople

)Risk of Lung Cancer from Radon Exposure (per 1,000)

US EPA 2003 Assessment of Risks from Radon in Homes

Average

indoor level

EPA action level

Indoor radon has been

measured in homes up to 3,200 pCi/L

Average

outdoor level

Prostate Breast Lung Colon Pancreas

23 23.6

50.6

16.710.8

Age-Adjusted Cancer Mortality Rates per 100,000

National Program of Cancer Registries, Centers for Disease Control and Prevention, 2005-2009 Data

Prostate Breast Lung Colon Pancreas

23 23.6

50.6

16.710.8

Age-Adjusted Cancer Mortality Rates per 100,000

National Program of Cancer Registries, Centers for Disease Control and Prevention, 2005-2009 Data

Radon in Schools Some states require testing in homes during real estate

transactions

Most states do not require testing in public schools

Children are especially susceptible to radon exposure• They breathe

proportionately more air than adults

• Their lungs are still developing

Problem StatementSchool districts do not have the means to test

every school in their jurisdiction on a regular

basis

Current publicly availabledata is limited to

county-level averages

Provide guidance to

school districts for focused

radon testing by performing

spatial analyses on indoor radon measurements from private

homes

Objective

DATA & METHODS

DATA School and residential results from the Florida Radon

Program

Soil characteristics, geology, and uranium concentrations from United States Geological Survey (USGS)

Temperature and precipitation from National Oceanic and Atmospheric Administration (NOAA)

Housing and poverty data from the United States Census (2010)

National Center for Education Statistics (NCES) school data

METHODS

Geocoding• Florida residential and school addresses and NCES

school addresses using Centrus desktop software• QA/QC of locational accuracy

Analysis• Maximum radon test result per location• Esri ArcGIS

o Bufferso Area proportion/weighted averages

• EpiInfo 7 odds and risk ratio calculations• Logistic regression (SAS 9.3)

PRELIMINARY RESULTS

FLORIDA DATA ANALYSIS - UNADJUSTED

56 173134 1150

>4<4

QUARTER MILESchool

>4 pCi/L

<4 pCi/L

Resi

dent

ial

190 1323

1513

1284

229OR = 2.78 (1.96, 3.94)

Mantel-Hansel x2 = 34.75 (p=0.0000)

RR = 2.34 (1.77, 3.10)

>4<4

HALF MILESchool

>4 pCi/L

<4 pCi/L

Resi

dent

ial

349 2690

3039

2446

593115 478234 2212

OR = 2.27 (1.78, 2.90)

Mantel-Hansel x2 = 45.32 (p=0.0000)

RR = 2.03 (1.65, 2.49)

FLORIDA DATA ANALYSIS – UNADJUSTED

205 993299 3020

>4<4

ONE MILESchool

>4 pCi/L

<4 pCi/L

Resi

dent

ial

504 4013

4517

3319

1198

OR = 2.08 (1.72, 2.52)

Mantel-Hansel x2 = 58.29 (p=0.0000)

RR = 1.90(1.61, 2.24)

>4<4

THREE MILESSchool

>4 pCi/L

<4 pCi/L

Resi

dent

ial

630 5546

6176

3654

2522

301 2221329 3325

OR = 1.37 (1.16, 1.62)

Mantel-Hansel x2 = 13.99 (p=0.0002)

RR = 1.33 (1.14, 1.54)

FLORIDA DATA ANALYSIS – LOGISTIC REGRESSION

  Estimate P-value OR 95% CI

Max. Radon Residential 0.0327 0.0069 1.033 1.00-1.058

Summer Precipitation 0.4405 0.0002 1.553 1.229-1.964

Spring Precipitation 0.4019 0.0192 1.495 1.068-2.092

Fall Precipitation -0.8143 <0.0001 0.443 0.315-0.623

Permeability -0.2437 <0.0001 0.784 0.726-0.846

Thickness 0.0288 0.0001 1.029 1.014-1.044

Hydrologic Group -1.4744 <0.0001 0.229 0.159-0.330

Drain 0.6371 <0.0001 1.891 1.443-2.478

Slope -0.2673 0.0047 0.765 0.636-0.921

Annual Flood Frequency 0.4714 0.0156 1.602 1.094-2.347

Average Fall Temperature 0.2141 <0.0001 1.239 1.135-1.352

Average Spring Temperature 0.2649 <0.0001 1.303 1.158-1.467

Uranium (ppm) 0.1017 <0.0001 1.107 1.075-1.140

FLORIDA DATA ANALYSIS – LOGISTIC REGRESSION

  Estimate P-value OR 95% CI

Summer Precipitation 0.4514 <0.0001 1.571 1.246-1.980

Spring Precipitation 0.3827 0.0001 1.466 1.050-2.048

Fall Precipitation -0.7966 0.02 0.451 0.322-0.631

Permeability -0.2559 <0.0001 0.774 0.717-0.835

Thickness 0.0297 <0.0001 1.03 1.015-1.045

Hydrologic Group -1.5541 <0.0001 0.211 0.147-0.303

Drain 0.6813 <0.0001 1.976 1.512-2.583

Slope -0.2601 0.0054 0.771 0.642-0.926

Annual Flood Frequency 0.4839 0.0129 1.622 1.108-2.376

Average Fall Temperature 0.2159 <0.0001 1.241 1.137-1.354

Average Spring Temperature 0.2584 <0.0001 1.295 1.152-1.455

Uranium (ppm) 0.1021 <0.0001 1.108 1.076-1.140

APPLICABILITY OF MODEL

Preliminary work not successful

Connecticut• Preliminary results unsuccessful• Summer and spring precipitation uniform

Ohio and Colorado to be processed

LIMITATIONS

Radon measurements are dependent upon:• Time of day• Time of year• Length of test• Building construction• HV/AC systems

Residential tests are voluntary

STRENGTHS

First assessment of potential radon risk using maximum result per location

First analysis to use proximity of residential radon test results and spatial association with schools nearby

First project to show potential utility of residential testing results to inform testing programs for public schools

NEXT STEPS

Refine model• Revisit the soil coding• Explore interaction effects• Include additional soil characteristics

Predictive Value Testing

Spatial analysis over time

Partner with other Federal, State, and local Agencies

Thank you!Jorge Laguna & Clark Eldridge/ Florida Department of Health, Radon Program

Francesca Provenzano, Connecticut Department of Health, Lead/Radon/Healthy Homes

Dr. Ashok Kumar, University of Toledo and the Ohio Department of Health Radon Program

Stephanie L. Foster, MPH, MA

For more information please contact Agency for Toxic Substances and Disease Registry

4770 Buford Hwy, NE Chamblee, GA 30341Telephone: 1-800-CDC-INFO (232-4636)/TTY: 1-888-232-6348Visit: www.atsdr.cdc.gov | Contact CDC at: 1-800-CDC-INFO or www.cdc.gov/info

The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention.

Agency for Toxic Substances and Disease RegistryDivision of Toxicology and Human Health Sciences

SLFoster@CDC.GOV770.488.38704770 Buford Highway, Mailstop F-09Atlanta, Georgia 30341