A CBET Nugget
Notable Accomplishments from CBET Awards

Green Cleaning Machines - How Plants Remove Pollutants from Soils and Sediments

Elizabeth Nichols, North Carolina State University

Background:  Professor Nichols and her team at North Carolina State University have discovered that some plants are doing more to clean up contaminated sediments than other plants.  This is important because the use of plants to clean-up contaminated environments is a growing, green business in the USA and globally.  If we improve our understanding of how specific plants successfully remove contaminants, we can transfer those strategies to other plants that may be more appropriate to a specific location.  We can also design other green technologies using the plant's green chemistry to treat current and emerging contaminants.

Results:  NCSU researchers first analyzed old, fuel-oiled sediments at sites where plants have naturally colonized from 3 years to 30 years.  They found that not all plants growing at these sites removed the aged, fuel-oiled contamination.  Plants that did remove aged, fuel-oiled contaminants released a great deal of plant matter into the sediments.  Radiocarbon dating was used to show how much plant organic matter was in the sediment relative to the fuel oil contamination.  Researchers also discovered that the released plant matter changed the sediment structure that initially slowed fuel-oil release to water where it can be toxic to aquatic organisms.  The more plant matter accumulated in sediments over time, the more fuel-oiled contamination was then released from sediments and degraded, probably due to sediment microbes supported by the deposited plant material.  Current laboratory studies are examining these processes in detail using isotopic tracer studies.

Elizabeth Nichols Image 1 
Non-vegetated and Phragmites fuel-oiled, contaminated sediments at Indiana Harbor Canal, IN

Credit:  Steve Rock, US Environmental Protection Agency

Elizabeth Nichols Image 2 
This illustrates the technology used to remediate contaminated soil.

Credit:  Elizabeth Nichols, North Carolina State University

Elizabeth Nichols Image 3
Methods used to achieve success.

Credit:  Elizabeth Nichols, North Carolina State University

Scientific Uniqueness:  Use of molecular analytical tools, such as radiocarbon dating and isotopic tracers, to understand why some plants are more successful at contaminant removal than others.

Impact on Industry:  The use of plants to clean up contamination is economically-attractive to private industry and government regulators.  This research advances the fundamental science behind a technology now widely used but not well-understood.

Impact on Society:  An important characteristic of plants that successfully clean-up aged, fuel-oiled sediments is that the plants release large amounts of plant materials to sediments.  This is a characteristic that can be designed into other plants for specific ecosystems.  This is research that can be used to improve our ability to live sustainably on Earth by developing better green technolgies that are economically-affordable.  Results from this study will improve our knowledge of how plants can be used to manage materials released from society into the environment.

Work is notable because it uses carbon cycling analysis to understand how aged fuel-oil cycles in sediment when specific plants are present.

This work involves multidisciplinary research and requires a research team with expertise in plant physilolgy, biogeochemistry, and environmental chemistry.

- - Primary Strategic Outcome Goal:  Discovery:  Foster research that will advance the frontiers of knowledge, emphasizing areas of greatest opportunity and potential benefit and establishing the nation as a global leader in fundamental transformational science and engineering.

- - Secondary Strategic Outcome Goal:  Learning:  Cultivate a world-class, broadly inclusive science and engineering workforce, and expand the scientific literacy of all citizens.

This work addresses the goals of the NSF Strategic Plan 2006-2011 and fits in with the strategic outcome goal for advancing fundamental discoveries in science and engineering.  The project improves on nanotechnology for drug delivery by designing materials that can interact with and utilize natural cellular machinery for improved delivery.

Program Officer:   Cynthia Ekstein
NSF Award Number:   0337453
Award Title:   Applications of 13C tracer studies and stable isotope geochemistry to determine rhizosphere alteration of PAH bioavailability in contaminated geomedia.
PI Name:   Elizabeth Nichols
Institution Name:   North Carolina State University
Program Element:   1179

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This Nugget was updated on 31 July 2008.