Posted on

EXH AR019624: Three Phase Back Calculations Table — Soil Cleanup Levels

Document Library
Sea-Tac Airport
Third Runway
PCHB
Box 09

This document presents three-phase back calculations for soil contamination levels at a site, listing various chemical constituents including heavy metals (arsenic, cadmium, chromium, lead, mercury, zinc) and petroleum products (TPH, gasoline, heavy oils). The table compares cleanup criteria from multiple regulatory frameworks including ambient water quality criteria (AWQC), drinking water standards, Model Toxics Control Act (MTCA) methods, and Fish and Wildlife Service ecological screening levels. The calculations were used to evaluate soil remediation thresholds based on leaching potential and ecological risk, with source references including EPA and MTCA SSL tables dated August 2001.

Open full document

Notes

AR019624: Three phase back calculations table for soil cleanup levels related to Sea-Tac Airport third runway EIS, filed with the Pollution Control Hearings Board (PCHB) of Washington State. Table lists constituents including antimony, arsenic, barium, beryllium, cadmium, chromium (total), Cr+6, copper, lead, mercury, nickel, selenium, silver, thallium, zinc, TPH (DRO), gasoline, and heavy oils. Columns include AWQC FW chronic, DW CLARC, Kd, AWQC 3-phase soil criteria, DW 3-phase soil, MTCA Method A, background, EWS DI ‘Wildcat’, EWS Eco upper 3 feet, Ecology mg/kg, and Ecology lower 6 feet values. Sources cited include EPA SSL table 46, MTCA, Model Toxics Control Act (MTCA) Version 3.0 Pub 94-145 August 2001, CLARC, and SQUIRT. Contaminants analyzed under four-phase leaching approach per MTCA.

Sidebar On/Off
V V