Removal Action Workplan for the Campbell Avenue Site
Summary
SCH Number
2005088040
Public Agency
Department of Toxic Substances Control
Document Title
Removal Action Workplan for the Campbell Avenue Site
Document Type
NOE - Notice of Exemption
Received
Posted
8/2/2005
Document Description
The project is the approval of a Removal Action Workplan (RAW) for the Campbell Avenue Site. The project involves the injection of Hydrogen Release Compound (HRC) and HRC Primer into the subsurface to treat groundwater contaminated with volatile organic compounds (VOCs), primarily, tetrachloroethylene (PCE), trichloroethylene (TCE), vinyl chloride (VC) and 1,2,4-trichlorobenzenes (1,2,4-TCB). PCE was detected at the highest concentration of 450 micrograms/liter (ug/l).
This removal action will reduce or eliminate a contaminated area of groundwater that poses a threat to human health. If monitoring data indicates the treatment with HRC is not effective, a Bio-Inoculum bacterium will be added to aid in the rapid and complete degradation of chlorinated VOCs. And if the treatment is found to be not effective, a contingency plan of groundwater pumping (at one day a month) for six months, and offsite disposal of extracted groundwater will be conducted.
Polychorinated biphenyls (PCBs) were also detected at 21.5 feet below the ground surface with the highest concentration at 1,300 mg/kg. At this depth, PCB exposure to the public is unlikely; restrictions will be imposed which will prevent digging below 15 feet in the area where the PCBs are without DTSC approval. There will be no restrictions on surface land use.
The cleanup objectives for groundwater are to protect public health and the environment by reducing the VOC concentrations in ground water to maximum contaminant levels (MCLs) or background concentrations. The MCL for each respective contaminant is as follows: PCE (5 ug/l), TCE (5 ug/l), VC (0.5 ug/l) and TCB (70 ug/l). MCLs are enforceable regulatory standards under the Safe Drinking Water Act and must be met by all public drinking water systems to which they apply. A screening level risk evaluation for VOC vapor in groundwater was conducted since MCLs do not consider vapor intrusion pathway. The findings indicate that MCLs are more stringent than the developed risk-based concentrations target (RBTCs) for the VOC vapor in groundwater. Therefore, the remedial action objectives of cleaning the groundwater contamination to MCL will address VOC vapor in groundwater.
Contact Information
Name
Virginia Lasky
Agency Name
Department of Toxic Substances Control
Contact Types
Lead/Public Agency
Phone
Location
Cities
San Jose
Counties
Santa Clara
Notice of Exemption
Exempt Status
Other
Type, Section or Code
Section 15061(b)(3)
Reasons for Exemption
The project will not have a possibility of significant effect on the environment because:
(a) The presence of clay and the aquitard act as barrier and help prevent the movement of contaminated groundwater from the shallow to the deeper aquifer zone. The site geology is made up of lean clay in the upper 23 feet of the site. All VOC contamination was encountered in the perched or very shallow groundwater between 5 and 9 feet below the ground surface. Below the 23 feet of clay is about 15 feet of shallow aquifer and underlain by another clay layer in which the thickness was not identified. However, a laterally continuous regional aquitard exists at depths of 100 to 250 feet bgs, which forms the division between the upper and deeper aquifer zones. The drinking water in the area is from the Santa Clara Valley basin, the deeper aquifer, located more than 200 feet below the ground surface. The closest municipal drinking water well is about 1/2 mile away.
(b) The project will consist of an in-situ treatment of groundwater involving the injection of Hydrogen Release Compound (HRC)/HRC Primer, a polyactate ester, an environmentally safe material and sometimes used as food grade. Once HRC is injected in groundwater, the VOCs will breakdown through reductive dechlorination to less hazardous substances.
(c) HRC/HRC Primer will be injected once into the groundwater by direct-push technology. Direct-push technology uses hydraulic pressure which does not entail the removal of soil and only a small hole is generated compared to the conventional drilling rig. After injection, groundwater will be monitored and if data indicates it necessary, injection of Bio-Inoculum into groundwater will be conducted. The targeted bacteria will expire once their VOCs food source is depleted.
(d) HRC and BDI will be injected in the vicinity of MW-3 and MW-5 using a grid layout. A 30-foot by 30-foot grid with several injection points will be employed to deliver HRC to the subsurface. The grid size was designed to optimize results. Once the material has been injected, an appropriate seal, such as hydrated bentonite, will be installed above the materials up to the top of the borehole which will be finished to match the surrounding surface.
(e) Groundwater will be monitored to determine the effectiveness of the treatment, and the condition of the groundwater. An operation and maintenance agreement will be in place to require groundwater monitoring and to ensure that cleanup goals have been achieved.
(f) All fieldwork will be conducted according to a site-specific Health and Safety Plan and only properly trained personnel will be employed. The Health and Safety Plan incorporates Department, Cal OSHA and Federal worker health and safety regulations requirements. Workers will be trained for hazardous waste handling and will be properly equipped for the material to be handled.
(g) The Removal Action Objectives for the site is to prevent human exposure to PCE, VC, and TCBs in groundwater at concentrations that present an adverse risk to human health; to prevent transport of PCE, VC, and TCB in groundwater to areas where concentrations could present an adverse risk to human health or the environment. The clean-up goal is to reduce the contaminants in groundwater to the Maximum Contaminant Levels.
Disclaimer: The document was originally posted before CEQAnet had the capability to host attachments for the public. To obtain the original attachments for this document, please contact the lead agency at the contact information listed above. You may also contact the OPR via email at state.clearinghouse@opr.ca.gov or via phone at (916) 445-0613.