Contamination field trials

Soil. The first reported field trial of the use of hyperaccumulating plants to remove metals from a soil contaminated by sludge appHcations has been reported (103). The results were positive, but the rates of metal uptake suggest a time scale of decades for complete cleanup. Trials with higher biomass plants, such as B.juncea, are underway at several chromium and lead contaminated sites (88), but data are not yet available. 

The slope of the land upon which the field trials will be established and the direction of the prevailing wind must be taken into consideration when locating the treated and untreated plots in a field trial. The protocol may specify a certain separation distance for the plots however, the PI must ensure that the plots are located with adequate separation to prevent contamination of the untreated plot during the course of the trial. The untreated plot must be located up-slope and up-wind from the treated plot to reduce contamination from wind or rain. When the land is level or the wind is not from a reasonably constant direction, then distance may be the only feasible way to ensure that plot integrity is maintained. Careful attention to plot placement in the field and documentation of this location in the field notebook will help minimize questions or concerns about the trial site during preparation of the final report. 

At a site in Texas where a Phytokinetics, Inc., technology has been proposed, projected costs are 390,000. Groundwater at the 22-acre site is contaminated with salts and heavy metals. Cleanup would involve planting eucalyptus and salt cedar trees. Projected costs include expenses associated with greenhouse studies, field trials, and a full-scale application (D22474I, p. D-5). 

The use of phosphate has been widely evaluated and subjected to field trials for Pb-contaminated soils. Most treatment systems involve excavation, pug milling of the soil with the stabilization agent, and either replacement or landfill disposal. Occasionally, for larger sites and deeper contamination, in situ mixing with large augers is used. 

The results from these and other laboratory studies have now led to the testing of various PCB bioremediation approaches in pilot demonstrations. The field trials are designed to demonstrate the applicability of field-scale treatment of soils, with the ultimate goal of commercial-scale bioremediation of PCB-contaminated sites, or demonstrated efficacy of intrinsic bioremediation. 

Martin, H., B.M. Patterson, and G.B. Davis. 2003. Field trial of contaminant groundwater monitoring Comparing time-integrating ceramic dosimeters and conventional water sampling. Environ. Sci. Technol. 37 1360-1364. 

Banuelos, G., Terry, N., LeDuc, D.L., PUon-Smits, E.A.H., and Mackey, B. 2005. Field trial of transgenic Indian mustard plants shows enhanced phytoremediation of selenium-contaminated sediment. Environmental Science and Technology, 39 1771-7. 

Passive sampling protocols were based on BSI PAS-61 (British Standards Institute, 2006), and triplicate field blanks were used to assess possible contamination during manufacture, deployment, retrieval and transport. In field trials it is not possible to produce controlled fluctuations in concentrations of pollutants, but by chance in this work concentrations of most metals were higher during the first 14 days of the 28 day trial and two peaks of concentration of were observed in the frequent spot samples... 

G.P. Warren, B.J. Alloway, N.W. Lepp et ai, Field Trials to Assess the Uptake of Arsenic by Vegetables from Contaminated Soils and Soil Remediation with Iron Oxides, Set. Total Environ. 311(1-3), 19-33, July 20 (2003). 

Weeks, J.M. and Williams, T.M. (1994) Preliminary Field Trial of a Method for the Rapid Assessment of Invertebrate Stress from Mining-related Arsenic and Heavy Metal Contamination Wanderer Gold Mine, Zimbabwe. Overseas Development Administration, London. 

Short-term field trials have been performed with GD droplets applied to silica sand at a contamination density of 5.21 g/m2 and laboratory experiments with GD liquid applied to soil (US Air Force, 2003 Murdock et al, 2004). These studies have demonstrated potential for GD offgassing due to volume displacement following actual and simulated rain events within hours after initial agent application. With repeated and simulated rain events, GD off-gassing from soil declined to nondetectable concentrations at 73.3 h post-application (following five simulated rain events). 

The chronic and acute response of agricultural crops and livestock to some contaminants, such as metals, is known from experimentation and guideline values are available. However, site-specific factors such as irrigation of crops and supplementary feeding of livestock can influence receptor exposure and there is a large impact of soil and local environmental conditions on agricultural yields, so field trials may be justified. 

Warren GP, Alloway BJ, Lepp NW, Singh B, Bochereau FJM and Penny C (2003) Field trials to assess the uptake of arsenic by vegetables from contaminated soils and soil remediation with iron oxides. Sci Total Environ 311 19-33. 

Marcus, S. Menda, A. Shore, L. Cohen, G. Atweh, E. Friedman, N. Karpas, Z., A novel method for the diagnosis of bacterial contamination in the anterior vagina of sows based on measurement of biogenic amines by ion mobility spectrometry a field trial, Theriogenology April 26, 2012 [Epub ahead of print]. 

Read, H. W., Fu, X., Clark, L. A., Anderson, M. A., Jarosch, T., 1996, Field Trials of a Ti02 Pellet-Based Photocatalytic Reactor for Off-Gas Treatment at a Soil Vapor Extraction Well , Journal of Soil Contamination, Vol. 5, No. 2, pp. 187-202. 

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