Client: Window Rock Unified School District
Project: Phase I Environmental Site Assessment and Limited Subsurface Investigation
Project Characteristics:
- Phase I ESA
- Regulatory Compliance
- Limited Subsurface Investigation
- COC Presence Evaluation
Project Detail:
Ensolum completed an American Society of Testing and Materials (ASTM) E1527-13 and US Environmental Protection Agency (EPA) “All Appropriate Inquiries” compliant Phase I Environmental Site Assessment (ESA) for a land parcel in Navajo Nation Arizona, as part of due diligence to understand the comprehensive history of the Subject Property. Ensolum worked with the client to understand the goal and purpose of the project while maintaining a balance with the project’s timeline and budget. The Phase I ESA was completed with the following four main components required by ASTM standard E1527-13 and AAI: Records Review, Site Reconnaissance, Interviews, and Summary Report. An Environmental Professional, as defined in 40 Code of Federal Regulations (CFR) Part 312.10, reviewed and issued the Phase I ESA.
Findings for the Phase I ESA included the identification of an on-site Recognized Environmental Condition (REC): a historical unpermitted landfill. Additionally, off-site RECs included leaking underground storage tanks (LUST) close to the Subject Property.
To further investigate the REC, Ensolum completed a Limited Subsurface Investigation (LSI) based on the condition that the buried waste was within the construction footprint of the planned development of a sports complex. The primary objectives of the LSI were to define further the nature and extent of the fill/refuse material and to estimate the volume of material that may need to be disposed of or addressed during construction. A secondary objective was to evaluate the presence or absence of chemicals of concern (COCs) resulting from the historical landfill and the potential of those COCs to impact subsurface soil and groundwater. The Subject Property is subject to regulatory oversight by the EPA;therefore, COCs were compared to the EPA Residential Regional Screening Levels (RSLs). Soil borings were installed utilizing a hollow stem auger drilling rig with continuous core bit, and soil samples were collected based on photo-ionization detection (PID) screening or visual and/or olfactory evidence of impairment. A final report was submitted to the client, which included a written summary of findings and recommendations.
