As demolition of the old 520 bridge continues, concern is growing about the levels of the arsenic, asbestos and lead going into Lake Washington. 33 pontoons – the most toxic parts of the bridge – were sold by the Washington State Department of Transportation and will be transported out of the area intact and reused. However, the remainder of the bridge needs to be dismantled and recycled or discarded.
According to WSDOT, “the contractor is dismantling the bridge in sections.” The contractor planned to demolish the sections in Kenmore, but citing health and environmental concerns the Kenmore City Council voted unanimously to not allow such work within city limits. In response, the contractor agreed that demolition work would take place on the barges in the middle of Lake Washington with the rubble then delivered to recycling facilities. While Kenmore claims a victory, environmentalists fear what this will be harmful to Lake Washington.
WSDOT says the contractor is using best practices on Lake Washington to contain the concrete dust, including containing the dust with a curtain, spraying down the dust with water and making sure that polluted water stays contained on the barge. The bridge is 70 percent removed already and 11 pontoons were safely floated out of the Ballard locks. However, as the dismantling continues the remaining pontoons are no longer attached to one another and are more vulnerable to wind and waves. WSDOT seeks to complete the deconstruction by the end of the year, saying that “a sense of urgency propels this work” as winter storms loom.
Environmentalists concerned about this approach met with WSDOT in July. When these discussions were unsuccessful, People for an Environmentally Friendly Kenmore sent letters to the U.S. DOT inspector general and the Federal Highway Administration to try to stop the bridge deconstruction. One member of PERK, Elizabeth Mooney said that “We want to know how the demolition’s “deconstruction” work will affect and impact the health of Lake Washington residents. I am certainly concerned that there are contaminants in that old bridge that could pose problems for public health and safety. But, how to get the answers and or comprehensive testing is a challenge right now.”
Other groups, such as the Green River Coalition and Laurelhurst Community Club share concern about the impact these chemicals will have on the lake. They are requesting air and water monitoring in the area near the demolition to see if any traceable amounts of arsenic or other contaminants are found.
The Green River Coalition received an email from the Department of Ecology saying it was starting to look into the amount of arsenic in the bridge and PERK received an email from FHWA Washington Division Environmental Program Manager Sharon Love saying the administration is working on a formal response to the concerns.
However, WSDOT denies that there is a concern. According to WSDOT Media and Construction Communications Manager Steve Peer, the level of arsenic in the old bridge’s concrete was tested in 2015 and 2016. The citizen groups rely on the 2015 test, which according to Peer “was performed to determine if the concrete was suitable for recycling.”
However, a different test, “designed to assess if the level of arsenic and other elements from the old bridge’s hardened concrete could leach into the environment if the concrete were placed in a landfill” was completed in 2016, and showed arsenic levels at 0.2 parts per million, which is “well below the EPA’s regulatory standard of 5 ppm for disposal.” Peer stressed that the 2016 test result is key because it indicates the amount of arsenic that could actually be released into the environment, as distinguished from a test of what is present, saying “When it’s encased in concrete, the amount that could potentially harm the environment is minimal.”