Seaplane Lagoon Dredging Raises Concerns
Radioactive alarm bells went off for many people when they saw the radiological warning signs posted on the fencing around the Seaplane Lagoon dredging operation. But so far, air readings have shown insignificant levels of radiation.
The first soil testing of the dredge mud will take place this summer.
operation was set up to remove sediment with other contaminants – PCBs, cadmium, chromium, lead, and pesticides. But because there is a chance the radium levels are elevated to risk levels, by federal law, the signs must go up.
The contractor handling the job requires that workers wear a dosimeter, or dose meter, that records cumulative exposure to radiation, and they are monitored daily. As of March 16, two months into the job, the readings have been 1,000 times below the hazard level set by the Nuclear Regulatory Commission.
The water that is draining off the dredge mud is being captured and treated before being released back into the Seaplane Lagoon.
Test results in mid-March for treated water going back into the lagoon showed radium-226 levels as “undetectable,” which is even better than the local average for drinking water. Drinking water is allowed to have minute amounts of radium-226, a naturally occurring element.
The Navy has been racing against the clock to complete the dredging of contaminated sediment from two areas of the lagoon before
endangered least terns return to Alameda Point in April to nest. They feed in the Seaplane Lagoon and surrounding waters, and disturbing them is against the law.
Even though the dredging crew has been working around the clock, some nights in the driving rain, it
has become clear to the Navy that the project won’t be completed in time for the terns. The Navy has been consulting the U.S. Fish and Wildlife Service, which manages the terns’ nesting area, about dredging options while the terns are here. Reading between the lines, that might mean dredging only at night.
One other reason for the rush: The dredged mud needs months to dry. And waiting until mid-summer to start the drying could make it all but impossible to remove the tainted sediment until next year. It will sit between the lagoon and the hangars until the fall, just before the rains are expected, and then hauled away. (In the video below you can see a heavy equipment vehicle with an attachment that looks like a cheese cutter on front. That’s for spreading the mud around to aid drying.)
One other thing:
Having the lagoon frontage covered in mud will throw a damper on getting any of the America’s Cup teams to set up shop for practice at Alameda Point in 2012.
The total cost for this dredging operation, from planning to
completion, is $25 million.
In other cleanup news, the Restoration Advisory Board – the citizen group that oversees Point cleanup operations – is challenging the Navy’s cleanup plans for the nearly million-square-foot Building 5. In a February 4 letter to the Navy, RAB co-chair Dale Smith and six other board members argue that the Navy hasn’t done enough to ensure it has identified all the contaminants in, around and under the building, the biggest on Alameda Point.
The Navy is suggesting that the contaminants be dealt with by a limited cutting out of some sections of concrete slabs and removing soil. The
board’s letter says the contamination could be much worse than expected under this massive building slab, implying that Alameda could one day find itself stuck with a toxic slug of a building. Board members are concerned that radioactive radium-226 could have leaked out of drain lines into soil under the slab due to age, earthquakes and the dumping of corrosive battery acid down drains. It takes 1,600 years for radium to break down, and as it does it produces radon gas, a serious health hazard.
Kurt Peterson and others on the board
have argued forcefully for the Navy to consider total demolition of at least Building 5A – a portion of the site, which is across the street from Rock Wall Wine Company – so that the ground can be cleaned once and for all. The Navy wants to impose so-called institutional controls on future landowners that would prohibit digging and drilling.
The Navy has agreed to get a fresh estimate for demolition of both Buildings 5 and 5A, but they
say Superfund law does not allow them to spend money on land improvements, meaning demolition, if it goes beyond the scope of necessary cleanup. It is unclear, however, if the law actually prevents the Navy from voluntarily spending the money for demolition.
The Navy is now doing a feasibility study for further work on the site
Originally published on The Island.