Chip’s Chevron, Jamestown, California

Soil and ground water samples were collected during the removal of four UST’s at this site.  During UST removal it was evident that both soil and ground water were impacted by gasoline.  A remedial overexcavation was conducted to remove contaminated soil.  A total of approximately 800 cubic yards of contaminated soil was removed and stockpiled for later disposal.  Free product gasoline was removed from the ground water using absorbent pads and approximately 30,000 gallons of impacted ground water was extracted from the pit.  Upon completion of the excavation, Oxygen Release Compound ORCâ, was placed in the pit to enhance natural degradation of any residual contaminants.  Subsequent ground water sampling indicated no detectable levels of gasoline or BTEX, with significantly lower levels of MTBE.

CMS Mobil, Garapan, Saipan, Northern Mariana Islands

American Geological Services, Inc. (AGS) was retained by Construction Material and Supply (CMS) to perform an underground storage tank (UST) closure investigation at the JoeTen Service Station located in Garapan Village, Saipan, CNMI.  The underground storage tank removal action was conducted in December 1996.  Soil samples and ground water samples were collected during the excavation of the UST’s.  Field observations and laboratory results indicated the presence of gasoline and motor oil range hydrocarbon contamination within the soil and ground water at the western end of the excavation. 

Engelhard Petroleum Catalyst Manufacturing Plant Demolition and Site Remediation

Cherokee Environmental Risk Management issued a $3,371,000 contract to AGS to demolish, segregate, and load out for disposal and or recycling the manufacturing facility and all support buildings, warehouses and storage tanks. Remediation of 27 Solid Waste Management Units associated with the production facility, and stabilization of approximately 1,000,000 cubic yards of alum sludge located on 230-acres of ponds.

French Gulch Wellington Oro Mill, Colorado

AGS conducted site and regional characterization studies in conjunction with the State of Colorado, U. S. Geological Survey, U.S. Environmental Protection Agency and the U.S. Bureau of Reclamation.  The objectives of these coordinated studies are to: determine the relative contributions of metal loading to French Creek from the various sources; identify metal contaminant pathways and fate; establish pre-remediation environmental baseline conditions; and design appropriate and cost effective remediation options. The characterization studies include Surface Mine Waste Characterization, Mine Pool Characterization, Surface and Ground Water Quality studies, Continuous Ground Water Level Monitoring, Monitoring Wells, Aquifer Testing, Stable Isotope Tracer  and a Salt Tracer-Injection study.

Hyatt Regency Hotel, Tumon, Territory of Guam

AGS conducted an Environmental Site Assessment and passive soil vapor survey of the Exxon UST fuel storage at the Hyatt Hotel site for Esso Eastern, Inc. This work included review of product inventory and AST maintenance and inspection records. A site inspection was conducted. The surface of the UST area was inspected for any visual evidence of contamination from the fueling operations. A magnetometer geophysical survey was conducted prior to the drilling of the borings for the goresorber vapor modules. Interviews with site personnel and Exxon maintenance personnel were conducted. GEPA records were reviewed and an environmental assessment report was prepared.

Jimtown Whistle Stop, Jamestown, California

A 4,000 gallon gasoline UST failed a precision tank test in 1991 and was taken out of service.  It was determined that between 400 and 600 gallons of gasoline leaked from the tank in one 24 hour period.  A diesel product line leak had also contributed to soil and ground water contamination.  Fractured bedrock underlying previously dredged stream sediments complicated the ground water flow pattern.  The ground water contaminant plume was delineated and a remedial action plan developed for the site.  Excavation followed by on-site bioremediation of the soils was determined to be the most cost effective remedial alternative.  The excavation was divided in separate phases to allow the owner to keep the service station operational.  Over 7,500 cubic yards of gasoline and diesel contaminated soil and bedrock was excavated and remediated.  A ground water monitoring program is currently being performed to monitor the effectiveness of the remediation. 

Marianas Cleaners TCE/PCE, Susupe, Saipan, Northern Mariana Islands

AGS conducted a soil and ground water investigation of the site and delineated a Tetrachloroethene , Trichloroethane , trans-1-,2-Dichloroethene, cis-1-,2-Dichloroethene and 2-Chlorotoluene contaminant plume. An emergency response treatment system was designed and installed using two extraction wells which consisted of activated carbon recovery. As of the end of 2000, over 30 million gallons of contaminated water have been successfully treated. Alternative treatment methodologies were evaluated and a new bioremediation technology is currently being implemented to greatly increase the rate of clean-up and reduce the remediation costs significantly. A passive soil vapor survey was conducted to delineate the lateral extent of the plume.

Marpi Point Hydrogeology, Marpi, Saipan, Northern Mariana Islands

AGS conducted extensive hydrogeologic studies for Asiana Airlines to provide 2,000,000 gallons per day of freshwater for two golf courses and a hotel and condominium complex. The scope of work included: well drilling; saline aquifer profiling; extensive long term pumping test; ground water tidal fluctuation monitoring; water quality analysis; geophysical testing; hydrologic modeling; calculation of saltwater upconing and permissible pumping rates; design of fresh water lens collection tunnel system; salt water barrier well system design; ground water recharge system.

Moccasin Point Marina, Jamestown, California

This project involved the initial emergency response, investigation, and remediation of a significant subsurface gasoline discharge, which was impacting the reservoir.  Gasoline leaked from several locations along a pipeline from gravity feed underground storage tanks connected to a floating marina.  The reservoir water level rose over 1.0 foot per day during the initial response.  AGS excavated a large quantity of contaminated soil ahead of the advancing water level, and installed numerous soil borings and monitoring wells. Approximately 90,000 gallons of contaminated ground water was collected from springs and interceptor trenches, then remediated and disposed.  The project area was then submerged below approximately 50 feet of water.  Monitoring wells were extended by AGS divers to facilitate monitoring.  Lake water contaminant and chemical parameter profiles, bottom sediment sampling, and remediation of excavated soils were also conducted.  Submerged soil borings were conducted with a barge mounted drill rig.  A final remedial excavation removed the remaining contaminants from the fractured bedrock beneath the reservoir.  Annual ground water monitoring is currently being conducted to monitor changes in ground water quality over time.

Middle Road Mobil, Garapan, Saipan, Northern Mariana Islands

AGS conducted an Underground Storage Tank (UST) Closure Investigation, site investigation and corrective action at the Middle Road Mobil Service Station.  This work included removal of the old UST’s, soil and ground water sampling, the installation of monitoring wells, recovery wells, vapor extraction trenches, and piezometers. AGS installed and operated an air stripper and vapor extraction system. A risk based closure assessment and solute transport model was prepared in support of a closure request. Additional assessment work for monitored natural attenuation is being conducted.

Neco Mobil, Koror, Republic of Palau

AGS conducted a Underground Storage Tank (UST) Closure Investigation at the Neco Mobil Service Station in Koror, Palau.  This work included installing soil borings and collection of soil samples. Analytical results indicated that the UST’s had not leaked. AGS is preparing to abandon the UST’s in place with sand due to the close proximity to the adjacent building.

Paoli Railroad Yard, Philadelphia, Pennsylvania

AGS was recently awarded a subcontract for excavation of an estimated in-place quantity of approximately 64,000 cubic yards of petroleum hydrocarbon and PCB contaminated soil. AGS will excavate and treat the soil using a Pug mill by mixing an estimated 45,000 cubic yards of cinders and ash with 12,400 cubic yards of reagent soils and 6,550 tons of Type I/II Portland Cement. This project will be completed by the end of 2002.

Pinecrest Road Yard, Pinecrest, California

Two 500 gallon USTs which contained gasoline and diesel respectively, were removed from inside of the shop maintenance building.  There was no evidence of leakage from either the tanks or the piping.  Nevertheless, the bedding material and ground water were impacted.  American Geological Services, Inc. overexcavated the fill material to clean granitic bedrock.  The water was purged with repetitive pumping until it contained no detectable contamination.  The main ground water aquifer is over 200 feet deep at the site.  The water in the tank excavation was derived from snowmelt and was perched above the impermeable bedrock.  As a result of the remedial activities, no additional soil or ground water investigation was required.

Platoro Mine, Colorado

AGS conducted a field investigation to evaluate the feasibility for using bactericide treatment to inhibit the accelerated oxidation of sulfide bearing mine wastes by the bacteria species Thiobacillus ferrooxidans. These bacteria are responsible for the conversion of sulfur into sulfuric acid. This acid solubilizes heavy metals and other leachable elements and toxins releasing them to surface and ground waters. AGS conducted a sampling and analysis program of the waste material and of the sulfide bearing vein zone. A test application of the bactericide ProMac was applied with a hydroseeder on one of the waste piles and along the highly fractured surface trace of the vein zone. The mine water and surface drainage waters will be monitored for the appearance of the ProMac and for the reduction in released metals concentrations.

Sierra-at-Tahoe, Twin Bridges, California

AGS completed a soil and ground water investigation at this ski resort located at an elevation of approximately 7,100 feet MSL in the Sierra Nevada mountains near Lake Tahoe.  The investigation included the installation of shallow soil borings, and the installation of ground water monitoring wells through granitic bedrock.  A remedial excavation was performed to remove gasoline and diesel impacted soils.  The excavated soils were remediated during the summer months and later used as clean fill material during site renovation projects.  Ground water monitoring was conducted to verify the effectiveness of the remediation, and a closure request is currently pending approval by the Regional Board.

Red Hill Mine, Angels Camp, California

AGS is performing post-closure monitoring activities at a former talc mine.  Surface and ground water sampling is conducted on a quarterly basis and storm event sampling is conducted semi-annually.  During site visits, AGS personnel conduct Standard Observations and Storm Event Observations in accordance with Regional Board mandates.  An electronic datalogger collects readings from moisture and other sensors that are downloaded and analyzed by AGS.  Quarterly reports and annual summaries include graphs of data obtained from the electronic sensors and laboratory analyses.

Susupe Mobil, Susupe, Saipan, Northern Mariana Islands

This project involved the collection of subsurface soil samples at discrete intervals from the surface to ground water and analysis for various hydrocarbon compounds. Four additional monitoring wells were installed. New and existing monitoring wells were developed and sampled. Tidal fluctuation data was collected using a data logger and pressure transducers installed in monitoring wells around the site. Aquifer slug testing was performed on the monitoring wells. AGS obtained permits and provided regulatory interfacing with the EPA and various local agencies. A final site assessment report was prepared for Mobil and the Division of Environmental Quality.  AGS removed the underground storage tanks and excavated the contaminated soil.  The soil was successfully remediated off site by aeration and bioremediation.  AGS prepared a final remediation plan and installed and operated an air stripping and air sparging system.

Tinian Mobil Bulk Plant, San Jose Tinian, Northern Mariana Islands

This Project involved the collection of subsurface soil samples at discrete intervals from the surface to ground water and analysis for various hydrocarbon compounds. A 100 gpm Shallow Tray Air stripper was installed to treat contaminated ground water generated during an aquifer pumping test. Existing monitoring wells were redeveloped and sampled. Tidal fluctuation was collected using a Hermitt 2000 data logger and four pressure transducers installed in monitoring wells around the site. AGS installed additional monitoring, recovery, and air sparging wells. AGS provided regulatory interfacing with the EPA and various local agencies. An air stripping and air sparging system is currently being operated by AGS to remediate the site.

Tuolumne City Road Yard, Tuolumne City, California

This project involved the design and management of a program for the bioremediation of hydrocarbon contaminated soil.  This work consisted of the bioremediation of excavated soil contaminated with gasoline, kerosene, oil, grease, and BTEX.  Soil mounds were constructed on bermed liners.  Nutrients and moisture were applied to each soil mound to enhance the activity of the naturally occurring microbial population.  Soil mounds were later augmented with additional bacteria.  The soil mounds were aerated to increase microbial activity.  Contaminant content was monitored by composite soil sampling and analysis.  The bioremediation successfully removed all of the hydrocarbon contamination and the soil was allowed to be disposed of as clean fill.

URIII Mobil, Chalan Kiya, Northern Mariana Islands

This project involved the collection of subsurface soil samples at discrete intervals from the surface to ground water and analysis for various hydrocarbon compounds. Monitoring wells were installed, developed, and sampled. Tidal fluctuation data was collected using a data logger and pressure transducers installed in monitoring wells around the site. Aquifer testing was performed and a hydrologic model prepared. AGS obtained permits and provided regulatory interfacing with the EPA and various local agencies. A final site assessment report was prepared for Mobil and the Division of Environmental Quality.  AGS removed the underground storage tanks and excavated the contaminated soil.  The soil was successfully remediated off site by aeration and bioremediation.  AGS prepared a final remediation plan and installed and operates soil vapor extraction, air stripping and air sparging systems.

Western Refrigerating & Cold Storage, Santa Maria, California

Gasoline contamination was discovered in soil borings installed through the former location of a 1,000 gallon gasoline UST.  Defining the lateral and vertical extent of contamination completed a soil investigation.  After the contaminant plume was identified a soil vapor extraction system was designed to remediate the site.  Three vapor extraction and four vent wells were installed and a vacuum was applied via an internal combustion engine.  The engine was operated on propane and used the extracted gasoline vapors as a supplemental fuel source.  The system was operated for a total of 59 days.  Confirmation soil boring data showed a decrease in BTEX levels between 91% and 100%.  The site was approved for site closure in March 1998.

Western Refrigerating & Cold Storage, Tracy, California

One 1,000 gallon gasoline UST was removed from the site in the late 70’s.  A Phase I and Phase II investigation indicated that gasoline contamination existed around the former tank location.  American Geological Services completed the lateral and vertical definition of the ground water plume and developed a Final Remediation Plan for the site.  The plan included the removal of approximately 1,500 cubic yards of soil both above and below the ground water table.  Mass calculations indicated that approximately 4,000 gallons of hydrocarbons were removed during the remedial excavation.  The excavated soil was aerated on-site to below detectable levels.  Oxygen Release Compound was installed in the final excavation to enhance passive remediation.  To date, ground water contaminant levels have fallen over 75% as compared with the pre-excavation levels.  The site is currently awaiting approval for case closure.