Miller Valley Road and Hillside Avenue

Registry placement date: Dec. 12, 2016

Score: 40

County: Yavapai

Location: Prescott, approximately bounded to the north by the Merritt Avenue alignment, to the south by Miller Creek, to the east by Division Street, and to the west by Miller Creek and Valley Street

Contaminants of concern: Chlorinated solvents tetrachloroethene (PCE) and trichloroethene (TCE).

Action taken: Chlorinated solvents tetrachloroethene (PCE) and trichloroethene (TCE) were initially detected in the area in 2002 during a leaking underground storage tank (LUST) investigation on the southeast corner of Miller Valley Road and Hillside Avenue. The investigation ruled out the leaking tank as a source of the PCE and TCE.

Further investigation in 2005 looked for potential sources of the PCE. Soil gas was found to contain PCE near the location of the former Village Cleaners (now a Fry’s Grocery store parking lot). Subsequent investigations found the concentration of PCE in groundwater to be up to 17,000 micrograms per liter (µg/L) at the former Village Cleaners location, which exceeds the Aquifer Water Quality Standard (AWQS) of 5 µg/L. This level of concentration may indicate that pure phase PCE may be present. PCE was also detected in groundwater near the current Village Cleaners. One soil-gas sample taken near the current Village Cleaners facility contained approximately 16,500 micrograms per cubic meter (µg/m3) of PCE. During the 2005 investigations, PCE was also detected above AWQS in two private irrigation wells.

A sampling event in 2015 identified PCE, TCE, and cis-1,2-dichloroethene (cis-1,2-DCE) in several wells in the area. Two samples had a PCE concentration above the AWQS of 5 μg/L. The highest PCE concentration was 418 μg/L, detected in a sample collected from a private irrigation well. The PCE concentration in this well had been at a lower concentration in 2005, indicating that there had been an increase in PCE concentrations at the site over time. TCE was also detected above the AWQS of 5 μg/L in a temporary boring in 2016 near Miller Valley Road and Hillside Avenue. No other VOCs were detected at concentrations above the applicable AWQS. It is unclear from the sampling conducted to date whether PCE concentrations detected above the AWQS in private wells originated from one or both of the potential sources mentioned above.

Community involvement activities: A community involvement area has been established and a fact sheet will be mailed to those located in and near the area. A public comment period related to the registry listing was announced.

Public Notice Proposal to List Miller Valley Road and Hillside Avenue on WQARF | View >