Part of the shoreline along the Oakland Estuary at Alameda Point has been upgraded with a prominent new pale gray stone embankment. While the aesthetic value is immediately apparent, the engineering value is not.
The Navy is nearing completion of plans for a cleanup area called Site 32, 60 acres that lie on the old airfield west of where the monthly Antiques Faire is held. The site requires remediation because investigators discovered radium-226 in the soil and on various objects. The Navy mixed radium-226, a naturally occurring mineral, with paint to allow dials and markers to glow in the dark. Repeated exposure to high levels of radium can cause cancer.
The Navy collected radium-impacted waste, such as used paint brushes from refurbishing dials and gauges, scraping solids, and rags, from its dial painting shop on a regular basis and discarded it at the Site 1 underground dump adjacent to Site 32. The Navy presumes that the radium-impacted items were spread beyond the dump site when the runway was expanded in the 1950s and a bulldozer was used to grade the area above the dump. Continue reading “Navy to create new wetlands”
The Navy’s cleanup program has not only removed toxic substances from below ground, it has dramatically improved some of the above ground environment by creating new native grassland and wetlands. January rains filled the Navy’s new seasonal wetland on the northwest shoreline corner of Alameda Point and fostered growth of newly planted native grass seed on the surrounding soil.
The 2.25-acre wetland lies within an approximately 37-acre shoreline cleanup area known as Site 1 at the confluence of the Oakland Estuary and San Francisco Bay. It is where the Navy buried its waste between 1943 and 1956. Most of the waste pits were covered by pavement in the mid-1950s when a new runway was added.Continue reading “Navy adds a wetland and grassland”
Navy environmental cleanup operations at Alameda Point ran the gamut during the summer and fall of 2014.
Operations included using bacteria to clean up groundwater, grinding radium out of a building floor, digging up lead-contaminated soil, constructing a metal shoreline waste barrier, digging up shoreline waste, preparing to install a 30-acre soil cover, constructing a new shoreline wetland, checking drain lines for contamination with cameras, and demolishing a several-acre temporary concrete drying pad near the old Control Tower.
The Navy began embedding a steel barrier along several hundred feet of the western shoreline of Alameda Point during the week of August 18. The purpose of the barrier is to contain contaminated ash and burn waste material that was bulldozed into the Bay some 60 years ago and is now overlain with silt. The area is where the Navy burned various waste materials.
The containment system is called a waste isolation barrier. It consists of 35-foot-long interlocking steel pilings that are hammered into the ground with a hydraulic vibrator suspended from a crane cable. Perpendicular steel walls behind the barrier add stability. The final elevation of the top of the waste isolation barrier will be approximately 10 feet above mean sea level.
Tests around the area were conducted in 2010, 2011, and 2012 to determine if any of the chemicals in the burn residue were entering San Francisco Bay. None were found to be entering the Bay. Nevertheless, the Burn Area’s proximity to the Bay requires that the contaminated waste either be removed or permanently isolated. Removing all of the waste from under the shoreline would have cost $40 million. The containment system costs $13 million.
The construction of the shoreline waste barrier is part of a larger Navy cleanup project on the adjacent 37 acres, called Site 1, which was once used as an underground waste disposal area. Much of the area is now covered by runway pavement that will remain in place. The entire 37 acres right up to the steel barrier will be covered with three feet of clean soil and seeded with native vegetation. A small wetland area will also be created along the shoreline.
When completed early next year, the area will be suitable for passive recreational use, including the Bay Trail.
The work can be observed from the Oakland side of the estuary at Middle Harbor Shoreline Park right next to the cranes.
The Seaplane Lagoon’s north side will be looking like its old self in a few months. The Navy has begun dismantling the waterproof concrete-walled containment system that was used for three years for dewatering and testing of soil dredged from the Seaplane Lagoon, marking a major cleanup milestone. Prior to that dredging work, much of the lagoon’s north frontage served as a staging area for replacement of storm drain lines contaminated with radium-226.
Construction of a new and improved soil cover over a waste disposal site concluded this spring, marking another milestone. The 110-acre site on the southwest corner of Alameda Point took 10 years of haggling about potential environmental impacts before a cleanup plan was adopted in 2010. Work began in early 2013. The dome-shaped soil cover required 500,000 cubic yards of barged-in soil to complete.
At the far northwestern corner of the Point, work is about to begin on another long studied and analyzed waste disposal site. In a few months, the Navy will be installing an interlocking steel retaining wall along 200 yards of the Bay shoreline to contain contaminated burned waste material that was bulldozed into the Bay more than a half century ago. Water dye tests showed no toxics are leaching into the Bay, but members of the Restoration Advisory Board (RAB) questioned whether the barrier would withstand a catastrophic earthquake. Partially covered by runway pavement, the entire 30-acre site will receive a three-foot soil cover. The work is expected to be completed in 2015. The area will be available for passive recreational use such as hiking trails when the city receives the land.
One of the longest-running and most problematic cleanup sites is at the old Naval Air Rework Facility (NARF), also known as Building 5, covering nearly one million square feet. Radium paint used for aircraft dial painting, and chemicals associated with engine repair work led to contamination that is still being remediated. The entire floor area will be scanned again for radiation in 2015, following up on at least three prior scanning surveys of walls, ceilings, pipes, and ducts. The year 2015 will also see the Navy returning to the site for a final round of groundwater cleanup treatments targeting contamination remaining after an intensive cleanup effort a decade ago.
Next door to the Bladium Sports Club on West Tower Avenue, another previously treated groundwater cleanup site will be treated again. Workers have already begun boring holes in the pavement for a network of hoses that will be used for introducing contaminant-eating bacteria into groundwater along with a bacteria food source.
On Saturday, July 12, the Navy’s annual cleanup site tour visited four of the cleanup areas. The most impressive stop was the 110-acre landfill site mentioned above. For the first time in over 15 years, members of the public were allowed to walk around and enjoy the magnificent views from the embankment that is closer to San Francisco than to city hall. The fencing is all gone, and with it the radiological warning signs. The Navy replaced an aging metal culvert that connects the site’s North Pond to San Francisco Bay with a concrete culvert.
Tour participants were able to see the area’s expanded wetland with a new tiny island. Caspian Terns started nesting on the island a few months ago, another type of milestone. “The last time Caspian Terns were seen in that area nesting was in 1999 when only one nest was detected,” said Alameda wildlife biologist and Alameda Point bird surveyor Leora Feeney. The 79-acre soil cover on the landfill will be seeded with flowering native grasses later this year. The vegetation mix was chosen by the RAB.
According to the Navy’s environmental cleanup coordinator, Derek Robinson, $513 million has been appropriated to date for Alameda Point cleanup, although some of it remains to be spent on upcoming work. His office, the Base Realignment and Closure Program, estimates another $80 million will be needed by the time remaining projects and follow-up monitoring are completed.
Later this year, the Navy is expected to transfer to the city the 33-acre North Housing site and seven-acre former Island High School site that sit next to Alameda Landing and Estuary Park, marking another milestone on the long and winding cleanup road to civilian use.
Update notes: Subsequent criticism of the Navy as to the necessity of a security fence by members of the public and regulatory agencies led to the removal of the security fence from the final work plan design. The Navy also agreed to shorten the soil gas vents to two feet, since only trace amounts of methane gas are now emitted from the landfill waste, most of which is industrial and did not produce methane in the first place. Additionally, the Navy agreed to examine the aging metal culvert that connects the North Pond of the West Wetland to San Francisco Bay. The culvert provides the water lifeline for the North Pond habitat and was at risk of collapse and being stopped up with debris. The Navy replaced the metal culvert with a concrete culvert (see photo above) and debris screen.
Site 1 at the northwestern tip of Alameda Point was used as the principal disposal area for all waste generated at Naval Air Station-Alameda from 1943 to 1956. This disposal area, which was once part of the Bay, was created by sinking pontoons and barges in the Bay and backfilling with dredge soil.
Disposal of cleaning solvents and petroleum products at one unlined pit within the landfill resulted in a groundwater plume that poses a threat of leaching into San Francisco Bay today.
In the 1990s the Navy installed an underground barrier system, called a funnel and gate permeable reactive barrier, to stem the flow of contaminants into the Bay. It was not a permanent solution. In July of this year the permanent solution began with the injection of neutralizing chemicals into the plume.
Protecting marine life
Most cleanup activities around the base are aimed at eliminating direct health risks to humans, such as from soil or from vapors that could enter a building. In a few cases, the cleanup is focused first on direct impacts to marine life such as fish, which could in turn cause health problems for people who eat them.
The cleanup effort at the Site 1 plume is one of those cases. This effort will keep toxins — solvents, petroleum products, and metals — from ever leaching into the Bay, being ingested by fish, and then consumed by humans. The effort will also reduce unacceptable levels of vapors that are escaping directly above the plume. The future use of the site will be restricted to open space recreational.
The chemical injection process, called In Situ Chemical Oxidation (ISCO), is accomplished by injecting oxidants (catalyzed hydrogen-peroxide and sodium persulfate) into the plume through injection wells. “These oxidants produce short-lived reactions that directly destroy the targeted contaminants,” according to the Navy. Groundwater tests will determine if further treatments are necessary.
Treatments will continue until either the groundwater is clean enough, or the solvent and petroleum concentration has been reduced by 75%. Once they get to 75% reduction, further injections are more or less a waste of money. From then on, the contaminant concentration is low enough that the remainder will either degrade or disperse and dilute naturally without posing a risk to fish or humans. This process is called natural attenuation and is often relied upon to finish the job when the bulk of contaminants are neutralized and treatment methods no longer yield effective results.
The groundwater plume is also contaminated with metals consisting of arsenic, copper, mercury, nickel, silver, and zinc. The metals problem will, in theory, be taken care of when the solvents and petroleum products are eliminated. This will cause the chemistry of the groundwater to change, which in turn will cause the metals to no longer remain dissolved in the water. The metals will return to their solid state and remain where they are. That’s the theory.
But to make sure it’s working, there will be a long-term groundwater monitoring program to make sure the metals aren’t moving. If problems arise in the future, the Navy will have to come back and design a new remedy. The Navy is responsible for the landfill’s contents staying in place in perpetuity.
The Navy opted not to remove the landfill contents because of the $93 million price tag and because the risk of contaminant releases was deemed low. A new set of environmental concerns associated with digging up and hauling away a landfill was also cited during the decision process.
The groundwater plume being treated is approximately 30 feet wide by 160 feet long, and it occurs mainly between depths of 5 and 10 feet below the ground surface.
Delay on soil cover
All of 30-acre Site 1 will eventually be covered with soil and seeded with native grasses. Work on the soil cover was delayed when the contractor discovered that the part of the landfill once used for burning waste was larger than expected. The documentation has to go back through the review process, with a work plan for the soil cover hopefully prepared and ready to implement by 2014.