Lake Union Dredging Ready to Commence (USA)

Barges have set up and are getting ready to dredge the bottom of Lake Union just west of Gas Works park. Larry Altose, from the Washington State Department of Ecology, writes about the work:

“The contamination we’re about to remove existed before the present owner purchased the property in 1994. At that time, Northlake Ship Yard and Ecology signed a legal document called a Prospective Purchaser Consent Decree (PPCD). It’s a cleanup agreement for someone who buys already-contaminated property.”

“Many commercial and industrial sites have such agreements, but this one has an unusual twist. Normally, a property owner – current or past – conducts the required cleanup work. Northlake Ship Yard opted instead to deposit funds into a bank trust account over several years. Ecology is using that account to conduct the cleanup. This is our first cleanup under such an arrangement.”

What’s down there

“A previous owner used ground-up slag from the Tacoma Smelter to sandblast ships. The slag was inexpensive and plentiful many years ago. It also was rich in arsenic, a toxic metal. Sandblasting also produces other residue from ships’ metal and paint. Today it is illegal to sandblast over the water.

We estimate that our contractor, Redside Construction of Port Gamble, will haul away about 8,000 cubic yards of this material all told. That may take about three months. Unless we find the contamination is much higher than we’ve seen in our sampling, we expect it all can go to a regular landfill.”

More info

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Source: wallyhood.org, December 6, 2013