Meri Barbafieri, Eliana Tassi, Chiara Mastretta, Rizzo Laura, Institue of Soil Chemistry, Italy

Phytoremediation for inorganic contaminants is entered as develop strategy using metal hyperaccumulating plant and/or chemical treatments inducing the increasing of metal availability to plant uptake. In fact in many contaminated soil metals are present in not bioavailable chemical forms. The metal bioavailability to plant uptake is the limiting factor in plant uptake. Many test are under evaluation with the goal to increase metal accumulation in plant. In this work are reported preliminary results from the first growing season at mesocosm scale located in the greenhause of research in the frame of the European project PhytoDec (1). The soil has been collected in a contaminated area in a manufactured gas plant located near Milan. Pb and As were investigated. These metals present different chemical behaviour consequently are objects of different mobilizing agents treatments.

Three different plant species have been used. Brassica juncea (as well known metal accumulator) Lupinus albus well common in Mediterranean area and very promising in metal tolerance and uptake; Holcus lanatus (promising plant for As tolerance and uptake). The selected metal mobilizing agents were; EDTA to mobilize Pb and BAP (ammonium phosphate biidrogeno) for As.

Heavy metal mobility has been evaluated by sequential extraction procedure for Pb as followed: H₂O, KNO₃, DTPA. For As only water extraction has been used.

Results showed a significant increasing in metal uptake by plants but in different rate and traslocation. In particular Brassica and Lupinus had the best accumulation rate for Pb and As compared to Holcus also after mobilizing agent addition. Analysis on metal mobility in soil confirmed the increasing of metal after the treatment. Pb extractability was increased in particular in water extraction and in EDTA extraction after the EDTA adding. With the BAP added As showed an increased extractability in water. This confirmed the increasing the mobility is also increasing the availability in plant uptake and so the metal accumulation in plant tissue.

Acknowledgement. We thank Lubrano Lamberto and Giorgio Poggio for technical assistance.

Meri Barbafieri, Institute of Soil Chemistry, and Alessandro Ciucci, SOING srl - Environmental Engineering

In the case of contaminated site it is now more and more urgent to develop new technologies to assure fast and affordable measure of contamination. Portable analytical instruments can give a fast and accurate monitoring of contaminated sites with lower cost when compared to the traditional laboratory analysis. They are particularly indicated for monitoring tool to characterize contamination level and diffusion, but also in case in case of in situ remediation technology it is fundamental to take under control how the technology is working. Phytoremediation is an innovative in situ remediation technology that use plants to remove or contain contaminants. It is characterized by low cost and low tech properties but it require long time to reach remediation goals and an appropriate low cost monitoring technology.

In this paper preliminary data on the application of LIBS technique are reported. LIBS (Laser Induced Breakdown Spectroscopy) has been used to carry out measurements of metals concentration in vegetal samples and compared to the traditional analytical techniques. SOING srl has developed a prototype of transportable instruments based on LIBS. The technique is based on the detection of light emitted form a micro plasma produced by a short laser pulse. The high temperature of the plasma ionize the material of the sample and after few microseconds atomic lines are emitted. No sample preparation is required. SOING use an own made procedure to find out trace elements in the sample and to determine the chemical concentration.

The same sample has been analysed by traditional laboratory analyses that comprehend different steps: drying, digestion and the metal analysis by Atomic Absorption Spectrometry. The test was focused on As and Pb. Results obtained from LIBS showed a real correlation with data obtained with traditional methods. The use of analytical portable instruments is of high concern in reducing cost and time in data obtaining.

Elena Dominguez and Dr. John Pichtel, Ball State University

Significant volumes of soil are contaminated via improper disposal of used motor oil. Phytoremediation holds promise for the degradation of aliphatic hydrocarbons, and for uptake of metals, both of which occur in waste motor oils. In a growth chamber study, the effects of several plant species and their associated microbial populations were evaluated in remediating waste-oil contaminated soils. A Glynwood silt loam soil was amended with 1% (w/w) used motor oil. Plant treatments included selected legumes, grasses, weeds (e.g., redroot pigweed, Amaranthus) and trees (Poplar, Populus Deltoides; Scots pine, Pinus sylvestris). Additional treatments included a commercial microbial culture and a mixed agricultural fertilizer. Soil samples were collected at 0, 50, 100, 150 and 200 days. Motor oil hydrocarbons remaining in the soil are being identified and quantified by gas chromatography/mass spectroscopy. The primary hydrocarbons detected occur in the nC14 – nC30 range. Various chain lengths show a propensity towards volatilization, biodegradation, and incorporation. Plant response to waste oil has been variable: grasses and trees tolerate the oil; however, legume shoot and root growth has generally been impaired. Counts of total bacteria, fungi and actinomycetes increased substantially with oil application until 50 days. However, a pronounced decrease is observed after 50 days. Additional studies are comparing motor oil hydrocarbon identification and quantification using Fourier-transformed IR spectroscopy and proton-NMR.

Victor F. Medina, Jeffery Lyon, Larry Dickinson, Washington State University Tri-Cities

Dairy farm waste accumulates at the rate of 30-60 pounds of manure and 2-4 gallons of urine per day per head. Growth of the dairy industry has generated the need for improved methods of manure management that are cost-effective and reliable. Pollutants from decomposing dairy manure can cause major problems, including surface and groundwater contamination as well as surface air pollution caused by odors, dust, and ammonia. Consequently, dairies are coming under increasing stringent environmental regulation.

Many dairies manage their wastes by washing them into lagoon systems. After settling, the solids are composted and the liquid portion is either recycled as wash water or land applied as irrigation water and fertilizer. However, dairies are being required to reduce their nutrient levels in their liquid lagoon wastes, prior to their land application (CFR 40, Parts 122 and 412).

Existing treatment technologies include lagoon aerators and rotational mixing technologies. These technologies require a significant capital investment, and are therefore better suited for larger dairies. Smaller dairies need less costly alternatives. Furthermore, these existing technologies target the removal of nitrate by nitrification-denitrification. Removal of phosphates is primarily from settling. More effective phosphate removal systems may be needed.

One option could be the use of plants to uptake and sequester excess nutrients. Plants have been used for this purpose to treat municipal wastes. These systems are relatively inexpensive and remove both nitrate and phosphate. However, dairy waste lagoons represent a harsh environment. High solids concentrations make them relatively opaque to light penetration and high organic content keeps dissolved oxygen concentrations very low. Furthermore, many dairy states are cold climate regions.

We propose using floating plants coupled with some simple engineering systems to help overcome these obstacles. Our experiments will consist of bench-top laboratory studies. Floating aquatic plants, such as duckweed and water hyacinth, will be investigated. Simple engineering systems will be tested.

Matthew D. Millias, P.E., Stephen J. Rossello, and David A. Brown, P.E. Parsons Engineering Science, Inc. (Parsons ES).

An Interim Remedial Measure (IRM) was completed in January 2000 for the Halowax Area (the Site) at the former ATOFINA Chemical, Inc. (ATOFINA) East Plant in Wyandotte, Michigan. Under the RCRA program as directed by the U.S. Environmental Protection Agency (Region V) and the Michigan Department of Environmental Quality, Parsons ES implemented the IRM for ATOFINA.

The IRM objective of minimizing DNAPL migration from the Site to the adjacent Detroit River was achieved by combining active containment and passive groundwater control. A steel sheet wall with joint sealant and a groundwater collection/treatment system was constructed to maintain an inward hydraulic gradient for active containment. In addition, 200 trees (willows and poplars) were planted to transition from active containment to passive groundwater control, a form of phytoremediation. In approximately 5 years from start-up, it is expected that the groundwater treatment system will be deactivated, and the trees will have the capacity to effectively maintain the required inward hydraulic gradient.

The Halowax Area is a relatively flat area (approximately 5 acres) immediately adjacent to the Trenton Channel of the Detroit River. Former operations at the Halowax Area included manufacture of chlorinated napthalenes, chlorinated benzene, chlorinated paraffin, chlorinated terphenols, epoxy resin and bisphenol. Wastes including still bottom residue (pitch) and salt precipitates were also managed at the Halowax area. The impacts to groundwater are limited to the shallow groundwater in the fill (mostly construction debris from the East Plant demolition) and silty sand layers in the north and northeast areas of the site.

Currently, 100% of the trees (10 – 15 foot high) have survived the first year and are growing well. The active containment system is being monitoring via groundwater wells and river elevation measurements.

Steven A. Rock, USEPA, Donald Schupp and Alan Zaffiro, IT Corp., Leslie Wilsong, USEPA

Landfill gas, consisting of methane and other gases, is produced from organic compounds degrading in the landfills, contributes to global climate change, is toxic to various types of vegetation, and may pose a combustion hazard at higher concentrations. New landfills are required to have an impermeable cap that prevents the escape of landfill gas and a system of pipes and pumps to collect the landfill gas. Older landfills may not have the proper design or necessary equipment to collect the landfill gas.

Planting landfills with specific types of trees and grasses has been suggested as a way to remove the methane from landfill gas by encouraging aerobic degradation of methane in the root zone (rhizosphere) by a process known as phytoremediation. It has been shown that methane levels decrease in the presence of growing plants; however, accurate determinations of the rate and amount of methane consumption have not been established.

A 100-gallon stainless steel tank, 35-inch diameter by 34-inch tall, is located in the chamber. A gas distribution diffuser placed within a 4-inch layer of gravel at the bottom of the tank, feeds methane (93 percent industrial grade) from a cylinder located outside the chamber to the soil via copper tubing. A manual control valve and rotometer, located at the cylinder, are used to control the flow of methane into the tank. Felt is placed above the gravel to prevent soil from entering the gravel layer and to aid in dispersing the gas.

Gas samples are collected from 2 slotted PVC pipes positioned vertically at different depths within the soil and from a slotted PVC pipe positioned directly on the soil surface to measure methane leaving the simulated cover. Air samples are collected above the tank. Samples are analyzed by direct injection of a GC/FID located in the adjacent control room.]