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Cleanup for Wynn casino includes polluted Mystic River

Development of the Wynn resort in Everett, shown rising in the background, includes a multibillion-dollar cleanup of the Mystic River.John Tlumacki/Globe Staff

A key challenge to building the $2.4 billion Wynn resort casino in Everett is cleaning up the environmental mess left by a succession of industries — in the Mystic River. Working around the clock, teams are removing pollutants beneath the water. By the time they finish next month, they aim to dredge 27,000 cubic yards of soil from the river, covering approximately 7 acres.

To learn more about the effort, Metro Minute talked with Patrick Herron, executive director of the Mystic River Watershed Association.

Q. Recount some the history of the site.

A. It is hard to imagine now, but as recently as the mid-1800s this area of the Mystic River, including the site of Wynn Development, was a healthy tidal marsh. The marsh was adjacent to a productive oyster bed that supplied the Union Oyster House. More than 500 clipper ships that sailed the world were built along the Mystic River from the 1600s through the 1800s. The first ship built by Europeans in Massachusetts, the Blessing of the Bay, was launched from the river’s shores in 1631. Ships primarily transported timber and molasses to rum distilleries located between here and the West Indies. From the 1860s onward, it became home to a series of chemical manufacturing plants, including New England Chemical, Cochran Chemical, and Merrimac Chemical. Monsanto acquired the site in 1929. The conditions on the site were a product of intense industrial use and lack of environmental protection. The site was so contaminated that it stayed abandoned for decades.

Q. What are challenges of a cleanup adjacent to a tidal estuary?


A. The first task was to literally remove huge volumes of contaminated soil and to physically encapsulate even more. The site used to manufacture sulfuric acid, so there were large expanses of acidic soil. There was lead and arsenic contamination. These are not challenges that the remediation, engineering, and science fields haven’t seen. But they require the marshaling of tremendous financial resources to plan, test, and execute the cleanup.


Q. What is the current quality of aquatic life in that area, and what species will benefit from a cleaner Mystic?

A. Remarkably, for such an urban river, with a dam at the mouth, the Mystic River hosts the largest single migration of river herring in the Commonwealth of Massachusetts. With the help of thousands of citizen scientists counting fish (mysticherring.org), we documented that 630,000 river herring — alewife and blueback herring — migrated from the ocean up through the dams to the Upper Mystic Lake in Medford to spawn in 2017. The kinds of cleanup and restoration being done at the Wynn site could help improve habitat for adult and juvenile herring.

Q. What oversight role, if any, is your organization playing?

A. The formal role of regulatory oversight is held by state and federal agencies, including the Massachusetts Department of Environmental Protection and US Army Corps of Engineers. The Mystic River Watershed Association, an environmental advocacy organization, participated in the public process that accompanies the myriad licenses and permits that Wynn was required to submit. We sought the best outcomes through comment letters and face-to-face dialogue. As an example, we worked hard to change the original plan for an armored shoreline to a “living shoreline”— new, constructed wetland habitat. We have also advocated for public access and sediment remediation in the river itself.


Q. Do you have any concerns so far about how Wynn is carrying out the Mystic remediation?

A. We are pleased with the remediation work. Wynn has invested approximately $40 million to remove or sequester hazardous soils and sediments. They hired highly competent firms to plan, guide, and execute the work. Adding the living shoreline and performing extensive dredging in that embayment are major environmental improvements that they deserve credit for.

Q: What is your group’s long-term vision for the Mystic?

A. A healthy environment for the diversity of people who live around the river, and at the same time a resilient river system that hosts abundant fish and wildlife habitat. That healthy environment includes well-designed and accessible open spaces along the Mystic River that allow pedestrians and bicyclists to move easily and safely in connected spaces along the river. We are beginning to realize this vision with improved water quality and with a Greenways Plan for parks and paths. We know that important improvements are coming over the next few years. We are excited to lead a public effort that helps create a world-class urban river in the Boston area with world-class parks. The Mystic can be a real showcase of the way that nature and intense human activity can exist side-by-side.

Roy Greene can be reached at roy.greene@globe.com Follow him on Twitter @roygreene.