HINKLEY — Pacific Gas and Electric Company was issued a new clean up and abate order.
The California Regional Water Quality Control Board, Lahontan Region released the order on Tuesday. The new order was issued to PG&E to clean up and abate the effects of the discharge of chromium waste or “threatened pollution or nuisance.”
The order combines outstanding requirements in previous orders and adds new requirements and deadlines for future cleanup and abatement actions.
According to Lahontan, the PG&E facility began operating in 1952 and discharged untreated cooling tower wastewater containing hexavalent chromium, which was used as a corrosion inhibitor. The water was discharged into unlined ponds until 1964.
The Lahontan report order explains that the wastewater percolated through the soil to the water table approximately 80 feet below, creating chromium contamination in the groundwater. The area beneath the former unlined ponds is also referred to as the “source area.”
Also on Tuesday, Kevin Sullivan, director of chromium remediation for PG&E, told the Desert Dispatch that remediation progress has been made in reducing the chromium hexavalent. PG&E has been involved in remediation actions since 1988.
PG&E has been using several different cleanup methods such as groundwater extraction and management, subsurface remediation and freshwater injection.
PG&E released its third quarter 2014 groundwater report and domestic well sampling to the water board. The report shows chromium in groundwater concentrations exceeding maximum background levels in three separate plumes in an area approximately 8 miles in length and approximately 2 miles in width throughout the Hinkley Valley and into Harper Dry Lake Valley.
The report shows three noncontiguous chromium plumes in the upper acquirer within this 8-mile area. In the lower acquirer, chromium is detected up to levels exceeding the hexavalent chromium drinking water standard of 10 ppb in a localized area east of Mountain View Road near Santa Fe Road. The report also says lesser chromium concentrations occur in the two detached northern plumes with exception of three hot spots of higher chromium concentrations.
The release form PG&E’s facility is the only known source of anthropogenic chromium in groundwater in the Hinkley upper and lower aquifers. The report says chromium detections above the maximum background levels in groundwater extending from the facility through the Hinkley Valley into the Harper Dry Lake Valley are considered a result of historical releases from the facility and are subject to investigation and remediation required in the order.
Currently, no residence or business in Hinkley has hexavalent chromium above the new drinking water standard in their wells. However, the order does specify that if any private supply wells in the affected area exceeds drinking water standards and the detections are linked to PG&E’s historical releases, replacement water must be provided.
Beginning on July 15 and every three months there after, the water board requires PG&E to submit quarterly reports.