Cleanup of contaminated groundwater between Alameda Point’s Seaplane Lagoon and Main Street is about to begin. The Navy will present its plan for doing so at this evening’s Restoration Advisory Board meeting. The meeting will convene at 6:30 p.m. at City Hall West, 950 West Mall Square.

At this meeting, the Navy will also review the longterm and costly maintenance plan for the soil cover over the underground dump at the northwestern tip of Alameda Point: an area to become city property and eventually part of a regional park. 

The lagoon cleanup area is directly south of the Site A residential and commercial parcel slated for groundbreaking later this year. It is one of the most difficult environmental cleanup areas to remedy at Alameda Point. This is why it has taken 20 years to decide what plan to implement.

A cleaning solvent used in the Navy’s industrial repair and refurbishing operations in this area leaked into the ground to depths of 70 feet and spread around nearly 19 acres. Prompt cleanup has been hampered by a maze of utility lines that preclude effective use of faster remedies such as heat-induced vapor extraction and injecting special chemicals to neutralize the toxic solvent. 

The Navy will instead have to rely on a slower method called bioremediation. Specialists will inject a special brew of cheese whey and vegetable oil into the ground to stimulate natural bacteria to digest the solvent. 

A limited test of heat-induced vapor extraction using high-voltage electrodes removed a significant amount of groundwater contamination but it only achieved part of the desired goals. A sewer line was damaged during installation of the 30-foot-long electrodes into the ground. Elsewhere, there are electrical lines from the Cartwright Substation that rule out the electrode heat treatment. 

If the Navy employs the method of injecting neutralizing chemicals, the various water, sewer, gas and electrical lines would interrupt the even dispersal of the chemicals. The pipes would be the path of least resistance through the soil and lead to uneven distribution. Stimulated bacteria, on the other hand, will become a self-replicating, self-expanding cleanup machine. 

It will take until the year 2023 before the land can be turned over to the city and then sold to private contractors for new construction. But in the year 2023, the land will still not be totally clean. It will come with restrictions due to the lingering potential for toxic vapor intrusion into nearby buildings. 

These buildings will require a special vapor barrier and vapor extraction system underneath the structures to provide protection until the goals for unrestricted use and unlimited exposure are achieved. Maximum cleanup goals will take between 25 and 40 years to reach, according to Navy documents. 

The horizontal extent of the contamination, plus a 100-foot buffer area, covers some 19 acres in the cleanup area known as Operable Unit 2B. Construction of buildings with ground-floor residential units or occupancies with sensitive receptors, including schools, child care facilities, hospitals, and senior care facilities, overlying the contaminated area plus the buffer are prohibited until the maximum cleanup goals are achieved.