Proceedings of the Annual International Conference on Soils: Volume 13, Issue 1
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Analysis of Sulfur in the Copper Basin and Muddy RIver Sites Using Portable XRF Instrumentation
Berger, Michael; Zou, Ling; Schleicher, Robert
The feasibility of using a portable analytical instrument, the Niton XRF XLt 500He, was tested as a technique for sulfur analysis of wet sediment or soil samples in the field. The effect of sample preparation on the precision and accuracy of sulfur determination was specifically evaluated. The Niton XRF XLt 500He uses X-ray fluorescence to detect different elements. This unit employs a helium purge to allow the analysis of elements lighter than potassium. Samples with sulfur varying from 0.3 to 2.0% were successfully measured with the instrument. The precision of the unit is excellent and the limit of detection can be extremely low with careful attention to sample preparation. The quantitation limit was estimated as 237 ppm sulfur.
Lead In Soil By Field Portable X-Ray Fluorescence Spectrometry— An Examination Of Paired In-Situ And Laboratory Icp-Aes Results
Binstock, D.A.; Gutknecht, W.F.; McWilliams, A.C.
A major aspect of lead hazard control is the evaluation of soil lead hazards around housing coated with lead-based paint. The use of field-portable X-ray fluorescence (FPXRF) to do detailed surveying, with limited laboratory confirmation, can provide lead measurements in soil (especially for planning abatement activities) in a far more cost-efficient and timely manner than laboratory analysis. To date, one obstacle to the acceptance of FPXRF as an approved method of measuring lead in soil has been a lack of correspondence between field and laboratory results. In order to minimize the differences between field and laboratory results, RTI International (RTI) has developed a new protocol for field drying and sieving of collected samples for field measurement by FPXRF. To evaluate this new protocol, composite samples were collected in the field following both HUD Guidelines and American Society for Testing and Materials (ASTM) protocols, measured after drying by FPXRF, and returned to the laboratory for confirmatory inductively coupled plasma atomic emission spectroscopy (ICP-AES) analysis. Evaluation of study data from several diverse sites revealed no statistical difference between paired FPXRF and ICP-AES measurements using the new method.
Bioremediation Of TOCs Present In Fuel-Contaminated Desert Mining Soil And Sawdust In The Atacama Region (Chile).
Reyes-Bozo, Lorenzo; Antizar-Lalislao, Blanca; Sáez-Navarrete, César; Godoy-Faúndeza, Alex
Repetitive small spills of fuel as diesel and lubricant oil during repair and maintenance of machinery as well as casual accidents within the mining industry constitute an unseen pollution of current environmental concern. The northern Chilean mining industry has not been an exception, where continuous fuel spills had occurred and had subsequently been adsorbed by desert soils and sawdust used as cheap sorbent materials to control environmental pollution. The resulting fuel-contaminated mixture is considered hazardous waste by the Chilean legislation, and thus contained in a hazardous waste landfill. Alternative options to landfilling and thus reduction of waste volume dumped in landfills consists of physical, chemical, and biological treatments or either combination, where bioremediation is a cost-effective alternative. Nevertheless, it remains unknown whether bioremediation of fuel-contaminated wastes is feasible under the environmental conditions of the Atacama region (Chile). In this study we determined the feasibility of bioremediation by aerated in-vessel composting of an aged fuel-contaminated desert mining soil and sawdust in the Atacama region. We investigated the removal of total organic compounds (TOCs) and changes in the microbial diversity during composting conditions at laboratory scale under controlled conditions of temperature, humidity and ventilation. Using biomolecular tools, we related contaminant removal to changes in the diversity of microbial communities.
Use Of Degradable, Non-Oxidizing Biocides And Biodispersants For The Maintenance Of Capacity In Nutrient Injection Wells
Horn, Brad; Richards, Gary
Fouling of water supply wells is a common problem dating from the time humans started using groundwater resources for water supply. In the groundwater remediation field, fouling of recovery and treatment systems has been a similarly common operating problem. Thus, it is not surprising, with the increased use of in-situ remedial methods, that fouling of in-situ treatment units is becoming a major design concern. In-situ treatment units include recovery wells, injection wells, recirculating wells, flow-through treatment cells, and in some cases, geologic formations themselves. The very effectiveness of these units depends greatly upon retention of permeability or hydraulic capacity. Capacity can be dramatically reduced due to fouling by naturally occurring inorganic precipitates or by microbial deposits. One of the least surprising instances of fouling of an in-situ treatment unit involves various bioenhancement techniques, where nutrients are injected with the intention of enhancing certain types of bioactivity and subsequent biodegradation of contamination. The data presented in this paper are derived from experience at remedial sites where bioenhancement activities have been self-defeating by causing a loss of permeability in injection wells, surrounding geological formations, or down-gradient recovery or recirculation wells. In these cases, non-oxidizing biocides, bio-dispersants, saponification agents or other additives have been applied to retain permeability in the hydraulic “bottlenecks” of these systems, such as injection wells and surrounding formations. Data collected from such applications shows that proper characterization of fouling mechanisms and subsequent application of well-designed deposit control programs can eliminate operational problems associated with fouling arising from bioenhancement. This paper introduces the key concepts in deposit control practices as they apply to fouling of in-situ treatment units. It provides an overview of the various agents and techniques used in such deposit control programs. Regulatory and design issues are discussed, and subsequently illustrated by a series of brief case studies.