Phytotechnology Projects

I have just gained access to this site. In 1968, chlordane was applied to a known area. Residual levels are around 5ppm but because of the urban location, 1ppm total DDX (DDT,DDE,DDD) and a number of PAHs are also present. I grew several cutlivars of zucchini and squash, as well as hybridized and backcrossed individuals of each. Zucchini has been shown to accumulate certain weathered persistent organic pollutants whereas squash does not. No results are yet available for this first year of the trial.

The site is an agricultural experiment station farm with residual levels of DDE from routine historical DDT application. I have been running field trials over the last 10 years as part of a research program on the potential phytoremediation of persistent organic pollutants like DDE/DDT. Zucchini and pumpkin were identified as plants that can accumulate significantly greater quantities of DDE in their roots and stems than other plants. Anecdotally, the highest soil DDE level in 2000 was 1ppm; this last field season, the highest level I could find was 0.4ppm.

A group of angiospermous herbaceous plants were assayed for symptomatic foliar changes in response to RDX contaminant levels found in soils of military ranges. Among five species selected for testing on the basis of RDX tolerance, only prickly sida (Sida spinosa) exhibited foliar symptoms upon exposure. At plant maturity red patches were produced in the leaf margins and interveinal chlorosis developed. Other members of the family Malvaceae are used to produce a red tea rich in anthocyanins. Because of these symptoms, there is potential for using prickly sida as a cost effective field and laboratory indicator of RDX contamination and for RDX phytoremediation.

A mixed hybrid poplar, willow, and loblolly pine system of 3,100 trees was planted at the U.S. Coast Guard Training Facility in Elizabeth City, NC, USA. This is a demonstration site for the North Carolina Department of Environmental and Natural Resources as part of the US EPA 319 Program. The main objective is to prevent the groundwater migration of fuels from former storage areas to the Pasquotank River. Soil gas analyses show an 85% reduction of total petroleum hydrocarbons from February 2007 to July 2010; groundwater concentrations of BTEX are below regulatory levels at key groundwater wells.

BES C, MENCH M, 2008 Remediation of copper-contaminated topsoils from a wood treatment facility using in situ stabilisation. Environ Pollut 156:1128-1138 MENCH M, BES C 2009 Assessment of the ecotoxicity of topsoils from a wood treatment site. Pedosphere 19:143-155 BES C et al 2010 Spatial variation of plant communities and shoot Cu concentrations of plant species at a timber treatment site. Plant Soil 330:267-280 MENCH M et al 2010 Successes and limitations of phytotechnologies at field scale: Outcomes, assessment and outlook from COST Action 859. J Soils Sediments 10:1039-1070 KOLBAS A et al 2011 Copper phytoextraction in tandem with oilseed production using commercial cultivars and mutant lines of sunflower. Int J Phytorem

The study has analyzed the capacity of nine ramie cultivars to absorb and accumulate Cd through two years of micro-regional field.The Cd contents retained in different parts of ramie are ranked as the following: bast > stems > leaves.Ramie has the ability to accumulate large amount of Cd; under the treatment with 1.65,25 and 100 mg kg-1 of Cd, three times of ramie harvest annually remove 0.25,0.76 and 0.97 kg hm-2 a-1 of Cd respectively.

Successfull removal of solids and metals, pH regulation and sulphate degradation have been reached in a treatment system that consisted of aeration cascade, sedimentation, limestone drainage, anaerobic gravel filter and algae containing treatment step.

On the site of the waste pile 371 of WISMUT the first constructed wetland (4 serially connected basins) for the biological treatment of mining water in Germany was designed and built. For the discharge into a nearby river water, uranium and arsenic have to be removed. Extensive investigations on the management, robustness and long-time stability of the constructed wetland have been carried out. The operation under properly controlled redox conditions is essential to achieve low arsenic and uranium levels at the same time.

The former municipal solid waste landfill Altablagerung Wannsee (AAW) in southwestern Berlin was chosen for installation of an evapotranspiration (ET) landfill cover design. This design relies on a qualified soil-vegetation barrier to minimize or prevent water from infiltrating into the underlying waste, thereby minimizing leachate generation. Scots pine (Pinus silvestris) saplings were planted on the AAW into the grass-covered top soil layer (silty sand compost blend) in 2005. Most of the 14,000 planted pines died the same year. Three experimental field plots were established in 2006 to tackle this problem, including the alternative planting of Austrian pine (Pinus nigra) and Norway spruce (Picea abies). The plot locations represent locally common topographical and exposure conditions. Ecotechnology means are being tested for increasing survival and growth of the conifers. Environmental site conditions are characterized regularly, emphasizing key soil parameters, vegetation composition, and weather.

During the remediation of the remains of former uranium mining and processing, the treatment of water contaminated with radioisotopes and heavy metals is a task of high priority. BioPlanta has undertaken extensive investigations into the treatment of water from the pit Pöhla-Tellerhäuser (Germany). The results of investigations with pilot scale constructed wetlands provided data about the treatment efficiency under varying hydraulic and material load, variability of the efficiency, remobilization of pollutants and the distribution of removed contaminants among the wetland media (gravel, plants).

Industrial wastewater of a tannery in Mexico is treated in a planted gravel filter. Through this the COD in wastewater is reduced below the regulatory limit value of 200 mg/l O2.

Liz Rylott and Neil Bruce (York), Sharon Doty and Stuart Strand (Univ. of Washington), Antonio Palazzo (US Army, USA CRREL) The toxic explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is both resistant to degradation and highly mobile through soils and ground water and, as a result of this, RDX is now a significant threat to drinking sources such as those close to the US Massachusetts Military. We have demonstrated that Arabidopsis expressing bacterial RDX degrading enzymes remove and degrade saturating concentrations of RDX from soil leachate. We are currently transferring this technology into selected perennial wheatgrass species for the phytoremediation of RDX from soil leachate.