Muskegon Lake’s Contaminated Sediment

Cleaned Up by Poplar Trees

Planting poplar trees around Muskegon Lake is helping remove toxins in the soil by absorbing and degrading the chemicals as the trees grow. The poplar trees also will reduce runoff and provide a sustainable source of wood for local manufacturers.

Description

The history of pollution around Muskegon Lake, Mich., from petroleum products, mercury, and PCB’s caused the lake to be listed as an Area of Concern—a designation conferred to the region’s most polluted waters—in 1985. Nutrient runoff from the surrounding landscape also caused large algal blooms and harmed the base of the food chain in the lake. As a result beach closings occurred, fish and wildlife were degraded and the public was warned not to consume them, fish and wildlife habitat was impaired, and dredging was restricted. Many projects are on-going to restore this complex ecosystem to health with a goal of removing the lake from the Area of Concern list by 2019.

One of these projects helping Muskegon Lake uses poplar trees to clean up toxins, absorb runoff, and contribute to the local economy. Poplar trees can contribute to the cleanup of the landscape through phytoremediation—a process where trees absorb toxins in the soil as they are growing. Poplar trees absorb heavy metals, chlorinated solvents, and volatile organic compounds and the trees then degrade the toxins or convert them into a non-toxic form. Soil can then stay in place, reducing run-off and erosion, and be cleaned up at the same time. This also circumvents the need to store contaminated soil offsite. Poplar trees are fast growing and great at absorbing water, helping to minimize runoff into Muskegon Lake. Finally, because the poplars grow so quickly, they can also contribute to the local economy, providing wood cabinets, doors, and paneling, or as a source for bioenergy production.

Resource Challenges Addressed

  • Contaminated soil
  • Polluted runoff

MUSKEGON LAKE REMEDIATION WITH POPLAR TREES

A root from a poplar that has absorbed pollution.

As part of this project, a few poplar trees are dug up and their roots are examined to analyze the rate of contaminate absorption. Here is a poplar root with just a little over one year of growth. Photo credit: Delta Institute.

Results and Accomplishments

 Planting over 3,000 poplar trees around Muskegon Lake has helped remove toxins from the soil, reduced stormwater runoff into the lake, and provided a sustainable source of wood for local businesses. These poplar trees are now absorbing heavy metals in the soil that would otherwise build up in fish and wildlife.

Holes in the ground waiting poplar trees

One of the brownfield sites in May 2013, just as the poplars are being put in the ground. Photo credit: Delta Institute.

On a brownfield site in Michigan, popular seedlings are planted to remove pollution

The same brownfield site as above in July 2014. Many trees are close to 10 feet tall, after only a little over a year of growth. The more these trees grow, the more contaminates they absorb. Photo credit: Delta Institute.