S.M. Abd-Allah, Soils Dept., Fac. Agric., Ain Shams Univ. Cairo, Egypt. P.O. Box 68, Hadayek Shoubra 11241, Cairo, Egypt, Email: samyabdallah@hotmail.com 
O.M. El Hussaini and R.M. Mahdy, Nuclear Materials Authority, Cairo, Egypt

Due to the increase concerns about the environmental pollution problems, it is so important in waste disposal management to perform an accurate exploration of geological barriers, which must be suitable for waste materials disposal. Clay sediments play an important role as natural adsorbents to immobilize heavy and nuclear metals contaminants.

For the present study, the clay samples were collected from either clay exploitation localities or from nearby radioactive mineralization in Egypt. Obtained results indicated that uranium adsorption and desorption differ importantly in accordance with the source of clay sediment used. In addition, its adsorption increases by increasing uranium initial concentration. The obtained data were found to fit of Langmuir equation isotherms.

Adsorption maxima (B) for uranium were high for Abu Tartur bentonite followed by El Hafafit vermiculite and was the least for Kalabsha kaolinite. However, the binding energy (b) that affects the adsorption process can be arranged in the opposite direction. Desorption of uranium by HCl, NaOH and tap water show clear ability of the different sediments to release uranium. This was a function of leaching solution and binding energy. Finally, the changes in the clay sediments through adsorption and desorption processes were investigated in detailed by I.R spectroscopy.

Soil Characterization Under an Operating Facility: An Innovative Approach

Dawn S. Kaback, Geomatrix Consultants, Inc., 1401 17^th Street, Denver CO  80202, Tel:  303-534-8722, Fax:  303-534-8733; Email: dkaback@geomatrix.com
Michael Frank, Fluor Fernald, 7400 Willey Road, Cincinnati, OH 45013, Tel:  513-648-5149, Fax:  513-648-4528, Email: michael.frank@fernald.gov
Robert Johnson, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL, Tel:  630-252-7004, Fax:  630-252-3611, rlj@anl.gov
Dan Ombalski, Directed Technologies Drilling, 451 Bailey Lane, Boalsburg, PA 16827, Tel:  814-466-7015, Fax: 814-466-7016, Email:  ombalski@juno.com

Closure of the Department of Energy’s Fernald Site near Cincinnati Ohio involves removal of all above-ground structures by 2006.  The preferred approach for the Transfer Tank Area (TTA) Building may involve leaving the building slab in place as a cost-effective alternative.  To first consider this option, characterization of the soils immediately under the slab to assess soil contaminant levels against final remediation levels (FRLs) for uranium, thorium, and radium had to be completed.  If the soil were found not to meet FRLs, an estimate of the volume of soil requiring on-site disposal was desired to facilitate the closure planning process.

Because vertical drilling through the foundation could not be done due to the presence of large tanks occupying most of the building’s floor space and angle drilling could not provide samples at multiple locations immediately beneath the foundation, horizontal directional drilling was deemed to be the only practical alternative for collection of core samples. 

A statistically-designed sampling plan for locating the boreholes and discrete sampling points called for collection of sixteen one-foot core samples, four from each of four boreholes at the target depth of ~six inches beneath the foundation (approximately 3.5 feet below ground surface).  A Vermeer 16x20 horizontal drilling rig was used to collect the samples from locations as far as 200 feet from four different launching points in clay and silty clay soils.  The project was successfully completed in nine days at a cost significantly less than the original estimate, proving the value of this technology for a specific application where site access is a particular challenge.  The analytical results indicated that a few sample results (<3%) were slightly above the soil FRLs for two contaminants.  The remediation plan for this area is yet to be determined.

Summer Indoor Radon Found to Exceed Winter Indoor Radon

Douglas Mose, Chemistry Department of George Mason University and Culpeper Center for Basic and Applied Science, George Mason University, Fairfax, VA, 22030, Tel: 703-273-2282, Fax: 703-273-5230, Email: dje42@aol.com
George Mushrush, Chemistry Department of George Mason University and Culpeper Center for Basic and Applied Science, George Mason University, Fairfax, VA, 22030, Tel: 703-273-2282, Fax: 703-273-5230, Email: dje42@aol.com
George Saiway, Chemistry Department of George Mason University and Culpeper Center for Basic and Applied Science, George Mason University, Fairfax, VA, 22030, Tel: 703-273-2282, Fax: 703-273-5230, Email: dje42@aol.com

It has been considered true for many years, probably because of commentary in US-EPA publications for the general public, that winter concentrations of indoor radon are greater than summer concentrations.  The higher amount of indoor radon in the winter is attributed to the observation that people normally keep their windows closed during the winter, allowing indoor radon concentrations to rise; the lower amount of in the summer occurs because people often open their windows, allowing outside air (which has very low radon concentrations) to enter.  Other US-EPA commentary mention that heavy rainfall causes a temporary increase in indoor radon.  It now appears that seasonal rainfall can cause unexpected indoor radon concentrations.  In a study of over 1000 homes, where indoor radon concentrations were measured each season over an entire year (a sequence of four three-month measurements), a summer with above normal rainfall had higher indoor radon measurements than the winters before and after this summer. Both winters had less precipitation than the Awet@ summer.

Measurement Uncertainty of Activated Charcoal and Alpha-Track Indoor Radon Detectors

George Mushrush, Chemistry Department and Culpeper Center for Basic and Applied Science, George Mason University, Fairfax, VA, 22030, Tel: 703-273-2282, Fax: 703-273-5230, Email: dje42@aol.com
Douglas Mose, Chemistry Department and Culpeper Center for Basic and Applied Science, George Mason University, Fairfax, VA, 22030, Tel: 703-273-2282, Fax: 703-273-5230, Email: dje42@aol.com
Fiorella Simoni, Chemistry Department and Culpeper Center for Basic and Applied Science, George Mason University, Fairfax, VA, 22030, Tel: 703-273-2282, Fax: 703-273-5230, Email: dje42@aol.com

According to US-EPA protocol, when a home is purchased it should be tested for indoor radon using a short-term (2-7 day) device like a container of activated charcoal, and the indoor radon concentration should be less than 4 pCi/L. When a home is tested because long-term occupancy is likely (e.g., many years), the test is commonly done using a long-term (e.g., 3 month) device like a container of film that can record the tracks produced by alpha tracks generated by radon and its immediate radioactive decay products.  For long-term occupancy, the US-EPA recommends that the indoor radon concentration be less than 2 pCi/L. In our study of the indoor radon in over 1000 homes, using both short-term (3 day) activated charcoal detectors and long-term (3 month) alpha-track detectors, we found that at the 70% confidence level, when trying to estimate the average indoor radon over an entire year, an uncertainty of +/- 90% had to be applied to single activated charcoal detectors and +/- 30% to single alpha-track detectors.

Urgent Removal of Uranium-Contaminated Wastewater

David A. Rountree, P.E., WRS Infrastructure & Environment, Inc., 625 East Tennessee Street, Suite 100, Tallahassee, FL 32308-4933, Tel: 850-531-9860, Fax: 850-531-9866, E-mail: drountree@wrsie.com
Chad Northington, WRS Infrastructure & Environment, Inc., 625 East Tennessee Street, Suite 100, Tallahassee, FL 32308-4933, Tel: 850-531-9860, Fax: 850-531-9866, E-mail: cnorthington@wrsie.com

WRS Infrastructure & Environment, Inc. (WRS) was called on by the United States Environmental Protection Agency (USEPA) Region 4 Emergency Response and Removal Branch (ERRB) to perform an emergency removal action at a former uranium processing facility.  Wastewater contaminated with depleted uranium and high concentrations of fluoride-chloride / potassium-sodium salts was threatening to overflow from two onsite evaporation ponds, due to fire damage to the overhead shed roof.  WRS was tasked by the USEPA to design, construct, and operate a wastewater treatment system to remove approximately 600,000 gallons of this liquid waste.

Working with the USEPA and the Technical Assistance Team, WRS performed bench-scale testing of a proposed treatment process consisting of precipitation of uranium phosphate followed by ion-exchange treatment.  The initial bench-scale testing identified that this proposed treatment process was not a feasible treatment option due to resin cost and performance.  A second bench-scale test showed that wastewater volume reduction by evaporation followed by concentrated liquid waste solidification would provide an effective, cost-efficient treatment method, allowing disposal of a solid waste greatly reduced in volume from the original wastewater.

WRS designed and constructed an onsite wastewater treatment facility utilizing three industrial evaporators with an aggregate evaporation rate of up to 6.3 gallons per minute and a volume reduction of approximately 89%.  The concentrated liquid waste is discharged to a lined roll-off and solidified with a sodium polyacrylate absorbent for disposal.  Significant disposal cost and time savings over alternative disposal methods were realized using this approach.

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