One Generation Plants a Tree, the Next One Gets the Shade
Erica Becvar, AFCEE/TDV, Brooks City-Base, TX 
Mahalingam (Ravi) Ravichandran, AFCEE/TDV, Brooks City-Base, TX 
Bill Doucette, Utah State University, Logan, UT
William Plaehn, Parsons, Denver, CO 

In Situ Phytoextraction of Polychlorinated Biphenyls (PCBs) from Contaminated Soils using Weeds
S.A. Ficko, Royal Military College of Canada, Kingston, Ontario, Canada
A. Rutter, Queen's University, Kingston, Ontario, Canada
B.A. Zeeb, Royal Military College of Canada, Kingston, Ontario, Canada    

Lowering TCE in Groundwater at a DOT site: Results from Air Sparging and Phytoremediation
Mary V. O’Reilly, New York State Department of Transportation, Binghamton, NY
Joseph Graney, Binghamton University, Binghamton, NY 
Ruth Ann Trudell, New York State Department of Transportation, Albany, NY

Naturally Occurring Phytoremediation? Using Native Trees to Assess Remediation Potential for TCE in Groundwater
Devon Rowe, ENVIRON International Corporation, Irvine, CA Carol Serlin, ENVIRON International Corporation, Irvine, CA
Antony Jones, ENVIRON International Corporation, Irvine, CA

In Situ Investigation of Phosphorus Dynamics in the Rhizosphere Solution of Wetland Plants in Field
Zhenyu Wang, Ocean University of China, Qingdao, China
Rong Wan, Ocean University of China, Qingdao, China
Shengfang Wen, Ocean University of China, Qingdao, China
Baoshan Xing, University of Massachusetts, Amherst, MA

One Generation Plants a Tree, the Next One Gets the Shade

Erica Becvar, MS, AFCEE Technology Transfer, AFCEE/TDV, 3300 Sidney Brooks, Brooks City-Base, TX  78235, USA, Tel:  210-536-4314, Fax:  210-536-4314, Email:  Erica.becvar@brooks.af.mil

Mahalingam (Ravi) Ravichandran, PhD, AFCEE Technology Transfer, AFCEE/TDV, 3300 Sidney Brooks, Brooks City-Base, TX  78235, USA, Tel:  210-536-5348, Fax:  210-536-2239, Email:  Mahalingam.Ravichandran@brooks.af.mil
Bill Doucette, PhD, Utah State University, Division of Environmental Engineering, Logan, UT, 84322, USA, Tel:  435-797-3178, Fax:  435-752-4661, Email:  doucette@cc.usu.edu
William Plaehn, PE, Parsons, 1700 Broadway Suite 900, Denver, CO  80290, USA, Tel:  303-831-8100, Fax:  303-831-8208, Email:  bill.a.plaehn@parsons.com

Between 1998 and 2005, Parsons, in partnership with the Air Force and Utah State University, implemented phytostabilization at six Air Force installations in the western United States.  Bases included Travis Air Force Base (AFB), California, Fairchild AFB, Washington, Vandenberg AFB, California, Hill AFB, Utah, Ellsworth AFB, South Dakota, and Altus AFB, Oklahoma.  During that time, over 4,000 trees were planted.  All of these plantings were focused on areas with shallow groundwater and chlorinated hydrocarbon contamination mainly consisting of trichloroethene (TCE).  After the initial plantings, the sites were monitored for the trees’ impact on the subsurface.  Tree growth and mortality were observed on an annual basis. Groundwater, plant tissue, and plant transpiration were monitored to determine impacts to the subsurface and uptake/consumption of contaminants from the newly planted trees. Results of the initiative, which concluded in 2005, were mixed.  Tree establishment and growth during the study were significant.  The subsurface irrigation systems were not used later in the program indicating the trees were using moisture existing at the site.  Tree mortality was low.  Plant tissue and transpiration gas sampling indicated update/consumption of TCE was occurring but groundwater results at the time indicated minimal impact to groundwater quality.  In summary, the plantings were well established but did not have enough time to develop the above and below ground root mass required to significantly impact the groundwater.    During the 2009 growing season, follow-up visits were made to Travis and Fairchild AFB to evaluate the trees progress and current impact on groundwater quality.  Groundwater samples were collected and trend analysis was conducted.  Plant tissue and phytovolatilization sampling was completed to assess degradation and translocation of TCE through the mature trees.  Results of this sampling will be presented.  

In Situ Phytoextraction of Polychlorinated Biphenyls (PCBs) from Contaminated Soils using Weeds

Student Presenter

S.A. Ficko, Royal Military College of Canada, Kingston, Ontario, Canada, K7K 7B4, Tel: 613-541-6000 ext. 3611, Fax: 613-541-6820, Email: sarah.ficko@rmc.ca
A. Rutter, Analytical Services Unit, School of Environmental Studies, Biosciences Complex, Queen's University, Kingston, Ontario, Canada, K7L 3N6, Tel: 613-533-2642, Fax: 613-533-2897, Email: ruttera@queensu.ca
B.A. Zeeb, Royal Military College of Canada, Kingston, Ontario, Canada, K7K 7B4, Tel: 613-541-6000 ext. 3611, Fax: 613-542-9489, Email: zeeb-b@rmc.ca

Polychlorinated biphenyls (PCBs) are a group of persistent organic contaminants that can adversely affect animals and humans. Due to their physical and chemical properties, the uptake of PCBs by plants was largely ignored by researchers for many years. Recent greenhouse and field studies focusing on the phytoextraction of PCBs from soil using various Cucurbita pepo (pumpkin & zucchini) species have shown encouraging results.

In this study, we investigated the uptake of PCBs into weeds over four growth seasons at two contaminated industrial sites in southern Ontario, Canada. Weeds were chosen due to prolific growth at both sites. They are also easy to cultivate and propagate, self-sustaining, inexpensive and less likely to be consumed by animals.

One field site was contaminated with Aroclor 1248, and the other with a mixture of Aroclors 1254/1260.  Eighteen weed species were investigated in triplicate from the first site, with shoot concentrations ranging from 0.4 ± 0.1 µg/g for lamb’s quarter (Cenopodium album) to 4.8 ± 4.1 µg/g for lady’s thumb (Polygonum persicaria). Shoot PCB concentrations for the fifteen species analyzed from the second field site ranged from 2.3 ± 1.4 µg/g for lady’s thumb to 35.0 ± 24.5 µg/g for tufted vetch (Vicia cracca). 

Bioaccumulation factors (BAFs) (BAF = [PCB]_shoot/[PCB]_soil) were used to compare the uptake ability of similar weed species between both sites. Seven common species were compared, and only the BAFs for sow thistle (Sonchus asper) were significantly different, indicating that BAFs may be species-dependent. Shoot extractions ranging from 2.9 ± 0.8 µg for yellow foxtail (Setaria pumila)  to 117.9 ± 26.2 µg for ox-eye daisy (Chrysanthemum leucantheumum) at the first site, and from 3.5 ± 2.4 µg for yellow foxtail to 415.6 ± 119.2 µg for Canada goldenrod (Solidago canadensis) at the second site were calculated.  Future density studies will allow for comparison of extraction between species based on optimal planting densities. This technique will help determine the most promising species for phytoextraction.   

Lowering TCE in Groundwater at a DOT site: Results from Air Sparging and Phytoremediation

Mary V. O’Reilly, New York State Department of Transportation, 44 Hawley Street, Binghamton, NY 13901, USA, Tel: 607-721-8138, Fax: 607-721-8129, Email:  moreilly@dot.state.ny.us
Joseph Graney, Binghamton University, Department of Geological Sciences and Environmental Studies, Binghamton, NY , USA, Tel:  607-777-6347, Email:  jgraney@binghamton.edu
Ruth Ann Trudell, New York State Department of Transportation, Geotechnical Engineering Bureau, 50 Wolf Road, Albany, NY 12232, USA, Tel: 518-485-0950, Email:  rtrudell@dot.state.ny.us

Trichloroethylene (TCE) is used as a metal degreaser and is associated with liver and kidney damage, decreased functioning of the immune system, impaired fetal development and cancer. 

In the mid-nineties the New York State Department of Transportation (NYS DOT) discovered TCE in the groundwater at one of its facilities in Broome County.  The source of the TCE contamination is under investigation.

The 0.2 acre site has shallow and deep aquifers.  Prior to air sparging TCE levels were measured at 966 ppb in the shallow aquifer (depth of 22 feet) and  237 ppb in the deep aquifer (depth of 35 feet).  An air sparging system with 15 shallow sparge points and 5 deep sparge points was installed in 1997.  The system was operated  from April 1, 1998 to September 20, 1999.  After sparging the TCE levels were 200 ppb in the shallow aquifer and less than 100 ppb in the deep aquifer. The levels of TCE in the shallow aquifer increased to 730 ppb within two and a half years of turning off the sparging system whereas those in the deep aquifer remained below 100 pbb. 

In an effort to find a more cost effective remediation approach 30 hybrid poplar seedlings  were planted in the spring of 2003.  Sampling since 2005 indicates that most of the TCE levels are below 200 ppb in the shallow aquifer and have remained below 100 ppb in the deep aquifer.  The results from phytoremediation are encouraging from visual and fiscal perspectives.

Naturally Occurring Phytoremediation? Using Native Trees to Assess Remediation Potential for TCE in Groundwater

Devon Rowe, ENVIRON International Corporation, 18100 Von Karman Avenue, Ste. 600, Irvine, CA 92612  Tel: 949-261-5151 Fax: 949-261-6202 E-mail: drowe@environcorp.com
Carol Serlin, ENVIRON International Corporation, 18100 Von Karman Avenue, Ste. 600, Irvine, CA 92612  Tel: 949-261-5151 Fax: 949-261-6202  E-mail: cserlin@environcorp.com
Antony Jones, ENVIRON International Corporation, 18100 Von Karman Avenue, Ste. 600, Irvine, CA 92612  Tel: 949-261-5151 Fax: 949-261-6202  E-mail: ajones@environcorp.com

Trichloroethylene (TCE) has been identified as the primary contaminant of concern in soil and ground water at a former industrial site in southern California.  The occurrence of shallow fractured bedrock and significant variations in depth to the water table have proved challenging in the design of remedial strategies.  Several remedial strategies are therefore being employed, including in-situ chemical oxidation, soil excavation, ground water pump-and-treat, and soil vapor extraction, to address separate areas of the >400 acre site. 

TCE concentrations in the plume area range from approximately 100,000 ug/l to less than 5 ug/l.  Phytoremediation is being considered as a likely remedial alternative in the distal portion of the plume, in an area where the depth to ground water is approximately 8 to 12 feet below ground surface.  This area hosts a variety of native plants and trees, and localized phytoremediation already may be occurring. 

Prior to implementing a full-scale phytoremediation project, the existing native trees (predominantly Pepper trees) were used to provide an assessment of whether phytoremediation was already occurring at the site.  The results of the preliminary field study, which consisted of the collection of tree-core tissues and headspace analysis of volatile organic compounds will be presented, along with implications for design of the full-scale phytoremediation project.  Consideration of additional phytoremediation assessment tools, including evaluation of co-metabolite concentrations, and subsurface microbial activity will also be discussed.

In Situ Investigation of Phosphorus Dynamics in the Rhizosphere Solution of Wetland Plants in Field

Zhenyu Wang, Ph.D., College of Environmental Science and Engineering, Ocean University of China, 238# Songling Road, Laoshan District, Qingdao, 266100, China, Tel: +(86) 0532-66782092, Fax: +(86)0532-66782092, Email: wang0628@ouc.edu.cn
Rong Wan, Ph.D., College of Fisheries, Ocean University of China, 238# Songling Road, Laoshan District, Qingdao, 266100, China, Fax: +(86)0532-66782517, Email: rongwan@ouc.edu.cn
Shengfang Wen, (M.Sc.) College of Environmental Science and Engineering, Ocean University of China, 238# Songling Road, Laoshan District, Qingdao, 266100, China, Tel: +(86) 0532-66782092, Fax: +(86)0532-66782092, Email: shengfangwen@163.com
Baoshan Xing, Ph.D. Department of Plant, Soil and Insect Sciences, Stockbridge Hall, University of Massachusetts, Amherst, MA 01003, USA, Tel: 413-545-5212, Fax: 413-545-3958, Email: bx@pssci.umass.edu

Phosphorus runoff into surface water from a variety of diffuse sources may lead eutrophication. The wetlands which buffer the interactions between uplands and adjacent aquatic systems become a key in phosphorus removal and retention. Phosphorus uptake by aquatic plants may make a significant contribution to the reduction of dissolved phosphorus in moving water toward aquatic systems. Therefore, it is critical to understand how different plants in wetlands take up and retain phosphorus before developing any effective mitigation scheme using plants.

In Nansihu wetland (China), micro-suction cups were used to collect samples of soil solution from the rhizosphere of six wetland plants root (Phragmites communis, Arundo donax, Typha latifolia, Scirpus validus, Zizania aquatica and Alternanthera philoxeroides), and capillary electrophoresis was used to determine the phosphate concentration of the soil solution. Root morphology, phosphorus uptake efficiency and phosphorus utilization efficiency, and rhizosphere pH were also analyzed to reveal the mechanism of phosphorus retention. The result indicated that T. latifolia was the most effective in phosphorus retention, followed by P. communis, A. donax and S. validus. Phosphorus in the rhizosphere solution (PO₄^3-, 0.37µg·L^-1) was significant lower than the bulk soil solution (PO₄^3-, 0.47µg·L^-1) for T. latifolia, but reversed for P. communis, A. donax, S. validus and A. philoxeroides; no significant difference was observed for Z. aquatica. Available phosphorus (Olsen-P) of the rhizosphere soil was fifty percent higher than the non-rhizosphere for A. philoxeroides, and seven to thirty seven percent lower than the non-rhizosphere soil for the other five aquatic plants.

This field study suggested that T. latifolia was efficient in the phosphorus retention with a strong root system. Although A. philoxeroides had high phosphorus uptake efficiency, the rhizosphere acification and phosphorus mobilization were significant. In conclusion, T. latifolia had a great potential to be used to in the wetland phosphorus retention, while A. philoxeroides should be avoided.

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