Featured Research

from universities, journals, and other organizations

'Green Clean:' Researchers Determining Natural Ways To Clean Contaminated Soil

Date:
September 24, 2009
Source:
North Carolina State University
Summary:
Researchers are working to demonstrate that trees can be used to degrade or capture fuels that leak into soil and ground water. Through a process called phytoremediation -- literally a "green" technology -- plants and trees remove pollutants from the environment or render them harmless.

Top -- March 2006: The Coast Guard site before trees were planted. Bottom -- July 2009: The same view in 2009. Some trees are now more than 30 feet tall. Bare spots indicate where bunkers were located and contamination is greatest.
Credit: Image courtesy of North Carolina State University

Researchers at North Carolina State University are working to demonstrate that trees can be used to degrade or capture fuels that leak into soil and ground water. Through a process called phytoremediation – literally a “green” technology – plants and trees remove pollutants from the environment or render them harmless.

Through a partnership with state and federal government agencies, the military and industry, Dr. Elizabeth Nichols, environmental technology professor in NC State’s Department of Forestry and Environmental Resources, and her team are using phytoremediation to clean up a contaminated site in Elizabeth City, N.C.

Phytoremediation uses plants to absorb heavy metals from the soil into their roots. The process is an attractive alternative to the standard clean-up methods currently used, which are very expensive and energy intensive. At appropriate sites, phytoremediation can be a cost-effective and sustainable technology, Nichols says.

The Coast Guard site was planted with a mixture of fast-growing trees such as hybrid poplars and willows to prevent residual fuel waste from entering the Pasquotank River by ground water discharge. About 3,000 trees were planted on the five-acre site, which stored aircraft fuel for the Coast Guard base from 1942 until 1991. Fuels had been released into the soil and ground water over time. Efforts to recover easily extractable fuel using a free product recovery system – also called “oil skimmers” – had stalled so other remedial options were considered before choosing phytoremediation.

“We knew that tree growth would be difficult on portions of the site due to the levels of fuels in the soil and ground water, but, overall, we thought the trees could keep this contamination from moving toward the river by slowing ground water flow,” Nichols said. “Trees need water for photosynthesis so they absorb water from the ground; that process can slow the amount of ground water flowing toward the river.”

In the process of absorbing water from the ground, trees can take up fuel contaminants. Some contaminants will be degraded by trees during this process while others will be released into the air by tree leaves and stems. “We wanted to demonstrate that the trees would first slow the movement of fuel toward the river,” Nichols said.

Trees can also increase the abundance and diversity of soil microorganisms around their roots. Some of these soil microorganisms will degrade the fuel still remaining in the ground. “This can be a slower process, but we also want to show that trees will remove the remaining fuel footprint over time,” Nichols continued.

Initially, 500 hybrid poplar and willow trees were planted in 2006. Another 2,500 trees were planted in 2007. “Our initial results are very encouraging, and amounts of fuel in the ground have decreased much faster than anticipated,” Nichols said, “but there is still much to learn about how trees can impact residual, weathered fuels over time. There are two areas on the site where trees do not do well, but, overall, tree growth and survival are impressive.” The Coast Guard has recognized the value of phytoremediation from this study, and has established two additional phytoremediation systems at different locations on base.

The project received a $240,584 grant from the U.S. Environmental Protection Agency and the N.C. Department of Environment and Natural Resources’s (NCDENR) Division of Water Quality 319 program, and an additional $15,000 grant from British Petroleum North America to establish the demonstration site. Nichols worked with Brad Atkinson (NCDENR), Dr. James Landmeyer (U.S. Geological Survey), J.P. Messier (U.S. Coast Guard), and Rachel Cook, a graduate student at NC State, to design and implement the phyto-demonstration site. NC State was recently awarded an additional EPA/NCDENR 319 grant to continue monitoring the site for tree growth and fuel reduction, tree toxicity to fuels, changes to ground water levels and flow, and how fuel contamination is actually removed by trees.


Story Source:

The above story is based on materials provided by North Carolina State University. Note: Materials may be edited for content and length.


Cite This Page:

North Carolina State University. "'Green Clean:' Researchers Determining Natural Ways To Clean Contaminated Soil." ScienceDaily. ScienceDaily, 24 September 2009. <www.sciencedaily.com/releases/2009/09/090917170912.htm>.
North Carolina State University. (2009, September 24). 'Green Clean:' Researchers Determining Natural Ways To Clean Contaminated Soil. ScienceDaily. Retrieved September 21, 2014 from www.sciencedaily.com/releases/2009/09/090917170912.htm
North Carolina State University. "'Green Clean:' Researchers Determining Natural Ways To Clean Contaminated Soil." ScienceDaily. www.sciencedaily.com/releases/2009/09/090917170912.htm (accessed September 21, 2014).

Share This



More Plants & Animals News

Sunday, September 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: San Diego Zoo Welcomes Cheetah Cubs

Raw: San Diego Zoo Welcomes Cheetah Cubs

AP (Sep. 20, 2014) — The San Diego Zoo has welcomed two Cheetah cubs to its Safari Park. The nearly three-week-old female cubs are being hand fed and are receiving around the clock care. (Sept. 20) Video provided by AP
Powered by NewsLook.com
Chocolate Museum Opens in Brussels

Chocolate Museum Opens in Brussels

AFP (Sep. 19, 2014) — Considered a "national heritage" in Belgium, chocolate now has a new museum in Brussels. In a former chocolate factory, visitors to the permanent exhibition spaces, workshops and tastings can discover derivatives of the cocoa bean. Duration: 01:00 Video provided by AFP
Powered by NewsLook.com
Could Grief Affect The Immune Systems Of Senior Citizens?

Could Grief Affect The Immune Systems Of Senior Citizens?

Newsy (Sep. 19, 2014) — The study found elderly people are much more likely to become susceptible to infection than younger adults going though a similar situation. Video provided by Newsy
Powered by NewsLook.com
Jury Delivers Verdict in Salmonella Trial

Jury Delivers Verdict in Salmonella Trial

AP (Sep. 19, 2014) — A federal jury has convicted three people in connection with an outbreak of salmonella poisoning five years ago that sickened hundreds of people and was linked to a number of deaths. (Sept. 19) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins