Location: 

• Vicinity of Silverbell Tree Drive and Silver Island Way, Tucson, Arizona

Acceptance Into Voluntary Remediation Program (VRP):

• Jan. 12, 2005

Contaminants of Concern (COCs):

• Benzene, Toluene, Ethylbenzene and Xylenes collectively known as BTEX
• MTBE

Affected Media:

• Groundwater

What are My Health Risks:

For Groundwater | If you are connected to a Public Water System (PWS) there is little to no risk of impact from exceedances because the water is filtered through the PWS for residential and business use | View Drinking Water Notices >

If you have a private well in the vicinity of the exceedance, we encourage you to test the well water

Not sure what to test for? | Learn More >

Site Summary:

The SFPP Silvercroft Wash Release has been managed under the oversight of the Arizona Department of Environmental Quality (ADEQ) Voluntary Remediation Program (VRP) since 2005. Offsite groundwater impacts are present, and stakeholders with downgradient receptors have been actively involved in the remedy selection and implementation process to address any potential impacts or concerns.

• Numerous early response actions (ERAs) have already been conducted including excavations, soil vapor extraction and liquid-phase hydrocarbon recovery.
• ADEQ issued a No Further Action (NFA) Determination for Non-Source Area Soils on Oct. 9, 2018.
• ADEQ issued a No Further Action (NFA) Determination for Source Area Soils on Nov. 12, 2019.
• This VRP Site is located directly upgradient from the Silverbell Landfill WQARF Site, which implemented a groundwater remedy in 2020. Given the proximity to the WQARF site, in lieu of completing a Feasibility Study, the Volunteer collected data through 2022 to determine the best remedy that is reasonable, necessary, cost effective, and technically feasible, while assuring the protection of public health and the environment. In addition, an air sparge pilot test was initiated in December 2020 to potentially optimize any proposed remedy.
• Results of the groundwater data and pilot test were incorporated into a Remedial Action Plan submitted for review and approval.
• The Remedial Action Plan proposed air sparge as a final remedy. The plan was approved in May 2023.
• Remediation progress reports are submitted after semi-annual monitoring and sampling events.
• First semiannual 2024 progress report reviewed November 2024.