Soil Contamination Data Analysis

EPA Superfund Site, Pueblo CO

• SQL • ArcGIS Pro • AutoCAD • Python (ArcPy) • Data Reporting • Stakeholder Deliverables

About the project: 


Pueblo, CO carries a long industrial legacy with having five lead and silver smelters operating from 1883 to 1908, leaving elevated arsenic and lead concentrations in residential and commercial soils across thousands of properties. In 2015, the EPA began a large-scale sampling and remediation effort expected to run through 2029.

Pacific Western Technologies was engaged to support the EPA's data collection and cleanup operation. My role was to manage the spatial dataset underpinning the entire project including but not limited to tracking sample results, flagging exceedances, and producing the data-driven deliverables that drove cleanup decisions for over 2,000 properties.

More background on the Pueblo Smelter Superfund site can be found here.

February of 2022 map of Pueblo, CO when I took over as GIS Analyst

My work

Data collection and digitization I began by digitizing each residential property in AutoCAD, classifying decision units (front yard, side yard, back yard) and recording square footage for each. This dataset became the spatial backbone of the project with every subsequent data point was tied to it.

Analysis against EPA thresholds Once field crews returned soil and dust sample results, I integrated the measurements into the geodatabase and evaluated each property against EPA contamination thresholds:

  • Arsenic in soil: 61 ppm

  • Lead in soil: 350 ppm

  • Arsenic in indoor dust: 61 ppm

  • Lead in indoor dust: 275 ppm

Properties exceeding any threshold were flagged for remediation. I used SQL queries to filter and extract exceedance records from the dataset, ensuring accuracy before any cleanup notification was issued.

Micro-scale of a parcel showing arsenic results mailed to a resident

Micro-scale of a parcel showing lead results mailed to a resident

Stakeholder reporting and resident communication For each property requiring cleanup, I produced a parcel-level map showing exact measurement values and mailed it alongside an EPA informational packet and scheduling instructions for the property owner. Every deliverable went through a QA/QC review before distribution.

Progress tracking I produced monthly project-wide maps for the internal team, visualizing cumulative progress across the study area. These maps were used in team meetings to communicate status, allocate field resources, and maintain project momentum across a multi-year timeline.

Conclusion

Over three years, this project tracked and processed data for more than 2,000 residential and commercial properties ranging from initial digitization through sampling, threshold analysis, and cleanup verification. The dataset I managed directly informed remediation decisions that improved environmental safety for current and future Pueblo residents.

This project is a clear example of how rigorous data management, spatial analysis, and clear stakeholder communication work together to drive real-world outcomes.

Initial parcel property map from February of 2022 when I took over as GIS Analyst

Most recent parcel property map from April of 2025. This map shows the massive amount of progress that the team has made over the 3 years