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ASPECT CONSULTING <br />62 FINAL PROJECT NO. AS190583A-08  MAY 21, 2025 <br />constituents not detected in either medium are not presented to make the table more <br />manageable. <br />5.3.1.1 Protection of Marine Water Quality <br />In accordance with MTCA, groundwater PCLs protective of surface water incorporate <br />MTCA surface water cleanup levels, including criteria from applicable state and federal <br />laws (WAC 173-340-730). For the protection of marine water quality, the PCLs are the <br />most stringent of the following aquatic life criteria (marine chronic) and human health <br />criteria for consumption of aquatic organisms under state and federal laws: <br /> MTCA standard Method B surface water cleanup levels based on human consumption <br />of fish (human health only); <br /> Washington State Water Quality Standards (WAC 173-201A-240); <br /> National Recommended Water Quality Criteria pursuant to Section 304(a) of the <br />Clean Water Act; <br /> Clean Water Act Section 303(c) (40 CFR 131.45) human health surface water criteria; <br />and <br /> MTCA Method B predicted protective concentrations of petroleum hydrocarbons <br />developed by Ecology under WAC 173-340-730. <br />5.3.1.2 Protection from Vapor Intrusion <br />Volatilization of contaminants in shallow groundwater is a potential issue in terms of VI to <br />current and future structures (indoor air). For the purposes of the RI, the MTCA Method C <br />groundwater VI screening criteria for industrial use 22 are used for the area outside of the <br />Warehouse Subarea (Table 5-1). For the Warehouse Subarea, the MTCA Method B <br />groundwater VI screening criteria for unrestricted use are used (Table 5-2). Air sampling <br />results can also be used to empirically assess the groundwater-to-air pathway, in <br />accordance with Ecology (2022). <br />5.3.1.3 Other PCLs <br />Many chemicals for which samples were analyzed as part of the RI do not have <br />groundwater PCLs based on either marine surface water protection or VI protection. For <br />those chemicals, MTCA standard Method B groundwater cleanup levels (based on potable <br />groundwater use), if available, are applied as groundwater PCLs for the purposes of the <br />RI, in accordance with WAC 173-340-720(6)(b)(i). <br />5.3.2 Soil PCLs <br />Consistent with the projected and/or potential future use of the Upland Area, soil PCLs for <br />unrestricted land uses are applied to the Warehouse Subarea and soil PCLs for industrial <br />land uses are applied to the rest of the Upland Area. The unrestricted soil PCLs are the <br />most stringent concentrations that are protective of direct contact by any human receptors <br />and soil leaching to groundwater. The industrial soil PCLs are the most stringent <br /> <br />22 From Ecology’s Cleanup Level and Risk Calculation (CLARC) database (February 2023). <br />https://fortress.wa.gov/ecy/clarc/CLARCHome.aspx