Bioremediation and Phytoremediation: Sulfate Treatment Systems Lead to Lower Downstream Methylmercury Bioaccumulation (Infographic)

This infographic depicts a landscape as a slice of the earth’s surface. This slice acts as the platform to demonstrate the watershed with blue streams braided within a generally green surface layer. The side view of the slice shows the roots moving through the upper soil layers with the lowest gray layer representing the bedrock.  The infographic also includes a depiction of the atmosphere and the industrial activities (power plants and open-pit minelands) in the head of the watershed. Smokestacks release pollutants into the sky and then by a cloud with rain drops delivering the sulfur, mercury, particulate matter, and other elements into the watershed.  Minelands release pollutants into the watershed through drainage. The text on the slide reads: Bioremediation and phytoremediation systems reduce potential impacts from sulfur emission by decreasing transport of sulfur discharge from industrial sources.

The pollutants are depicted as red dots flowing downstream that are coming from industry and drainage from the mine site all entering the main watershed streams.  The landscape divides in two braided stream segments.  The left segment consists of a planted forest of specialized poplar trees covering the sloping landscape. On the main stem of the left channel is a constructed wetland.  The water flows through the constructed wetland which helps treat the polluted water. On the right side of the watershed, the stream tributary flows through a planted forest of specialized poplar trees designed specifically for remediating and stabilizing the pollutants through a process called phytoremediation. 

Large red arrows overlaying the infographic show the path of the pollutants from the industrial and mining sources to downstream. As the pollutants are treated, the arrows get smaller until they reach the next lower portion of the watershed post treatment and turn yellow to demonstrate a lower level of pollution as the water continues to move down stream. 

In the lower area of the watershed, a wetland is depicted on the left side of the diagram. Native bird species, such as herons, loons, and ducks, as well as native wetland vegetation is present. In the main channel of the stream below the braided system is a protected cove with Manoomin (wild rice) growing. Within the patch of wild rice are two people canoeing to harvest the rice. Sulfate pollution can diminish the resilience of Manoomin and hinder opportunities for harvesting. 

One the right side of the infographic below the planted forest and just offshore in the main stream a man enjoys freshwater fishing from a flat water boat. Several fish are depicted in the main stream channel near the surface as well as in deeper waters viewed from the front side of the earthen slice. On land a family picnics in a flat meadow area and a small child enjoys time with dad. A pregnant mother walks a small child in a stroller. Health issues related to mercury are especially acute for mothers and their babies, and other young people. Opportunities for fishing and enjoying activities near surface water bodies is hampered because of sulfate and mercury pollution.  Additionally on the infographic are two pullout windows and a legend. 

Pull out window 1 highlights the removal and capture of pollutants passing though the constructed or engineered wetland treatment system. The treatment systems rely on physical, chemical, biological, and hydrological processes to transport and reduce contaminants in a targeted treatment zone, thus requiring relatively little infrastructure and routine maintenance. The system is composed of specialized geomedia, natural-occurring microorganisms, and cover plants with engineered operation. Through the treatment, sulfate levels (red dots to smaller yellow dots) will be reduced and recovered in the geomedia, limiting the transport of sulfate to sensitive freshwater ecosystems.

Text on the slide: Engineering solution technologies, such as constructed or engineering wetland water treatment systems, remove excess sulfate from polluted water.

The legend beneath this pullout on the far left lower corner shows a red hexagon for sulfate pollutants. A solid yellow circle depicts the stable (or metabolized) sulfate pollutants.

Pullout number two is a depiction of a specialized poplar tree that is treating the sulfur and sulfate pollutants through phytoremediation processes in the soil (such as, the area directly surrounding the tree roots known as the rhizosphere), as well as the tree roots, wood, and leaves. The transition of color from red to yellow depicts stabilization and cleaning of the pollutants via processes in the soil and tree tissues. In particular, the yellow pollutants released into the soil and air represent stable (less harmful) forms of the red pollutant dots. 

Text from screen reads: Phytoremediation sustainably mitigates sulfate pollution by using specialized trees to stabilize, uptake, and transform the sulfate. 

A text bubble overlaying the bedrock at the bottom of the screen reads:

Bioremediation and phytoremediation systems reduce the production of methylmercury by: 1. Decreasing levels of excess sulfate in the environment 2. Minimizing the transport of sulfate to areas of mercury accumulation, and potential methylation hotspots (such as, wetlands).

Overall, this infographic visually depicts this statement: The combination of biological sulfate treatment and phytoremediation technologies that limit mercury and sulfur transport to sensitive freshwater ecosystems downstream like Manoomin waters and methylation hotspots will sustain the benefits nature provides to people and communities and reduce the impacts of mercury and sulfur on human health and the environment.