uptake. There are 3 main planting techniques for phytoremediation. 1.Growing plants on the land, like crops. This technique is most useful when the contaminant is within the plant root zone, typically 3 - 6 feet (Ecological Engineering, 1997), or the tree root zone, typically 10-15 feet. 2.Growing plants in water (aquaculture). Water from deeper aquifers can be pumped out of the ground and circulated through a “reactor” of plants and then used in an application where it is returned to the earth (e.g. irrigation) 3.Growing trees on the land and constructing wells through which tree roots can grow. This method can remediate deeper aquifers in-situ. The wells provide an artery for tree roots to grow toward the water and form a root system in the capillary fringe. Determining which plant to use: The majority of current research in the phytoremediation field revolves around determining which plant works most efficiently in a given application. Not all plant species will metabolize, volatize, and/or accumulate pollutants in the same manner. The goal is to ascertain which plants are most effective at remediating a given pollutant. Research has yielded some general guidelines for groundwater phytoremediation plants. The plant must grow quickly and consume large quantities of water in a short time. A good plant would also be able to remediate more than one pollutant because pollution rarely occurs as a single compound. Poplars and cottonwoods are being studied extensively because they can used as much as 25 to 350 gallons of water per day, and they can remediate a wide variety of organic compounds, including LNAPL’s. Phytoremediation has been shown to work on metals and moderately hydrophobic compounds such as BTEX compounds, chlorinated solvents, ammunition wastes, and nitrogen compounds. Yellow poplars are generally favored by Environmental Scientists for use in phytoremediation at this time. They can grow up to 15 feet per ...
