Pierce County's Children and Soil Contamination
Given Tacoma’s industrial history, it is no surprise the environment has felt its impact across Pierce County and beyond. Yet, as regulations are continuously updated and new urban development occurs, the conditions of the past can be buried beneath the surface.
Considering children may be the demographic most significantly impacted by toxins found in soil, this study compares the density of children with the concentration of arsenic and lead in Pierce County soil. A spatial analysis reveals areas most in need of remediation to be in northern and eastern Tacoma.
Density of Children Age
10 and Under
Darker colors indicate areas of greater child density. Values range from zero (light tan) to 50,000 (dark grey).
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Data for children in Pierce County were reduced to those 10 years of age and younger. Classified into block groups, the density was calculated by number of children per square mile. The calculated density was then visualized by the Inverse Distance Weighted method of interpolation.
Arsenic and Lead Soil Concentration
Increasing intensity of soil contamination is shown from light tan to dark red. The values of arsenic concentration range from 5ppm to 140 ppm, and lead values include 21ppm to 363ppm.
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Illustrated concentration of both arsenic and lead can be estimated through the Kriging method of interpolation that was accomplished. Classification for the concentration of arsenic and lead seen was made using standard deviation, but their relative concentration in parts per million are also shown for reference.
Using the raster calculator, the variables of child density, arsenic concentration, and lead concentration were combined to analyze the areas of Pierce County that are in most need of remediation based on the highest concentration of both child density and soil contamination.
Download the traditional poster format of this map analysis
Analysis completed March 3rd, 2019.
Projection: NAD 1983 StatePlane HARN Washington South FIPS 4602 Feet
Sources: Department of Ecology, U.S. Census Bureau, Pierce County GeoSpatial Data Portal