Soil columns

Figure 7 The production and emission of NO during denitrification in agricultural soil treated with NO3 fertilizer (KNO3) and the nitrification inhibitor Dyciandiamide (10%) under aerobic (air) and anerobic conditions (N,). Fluxes are means from three soil columns, error bars represent standard deviations from the mean. V = vertical flow through the column H = Horizontal flow over the soil surface.

The two surface dusts most studied are street and house dusts. As with atmospheric dust there is a remarkable agreement in the concentrations of the elements in either street or house dusts taken from a wide variety of sources (73). Therefore it is possible to estimate median concentrations for each element in the two dusts. The estimates are listed in columns 8 and 9 in Table H. One feature is that the concentrations of the elements in the two dusts are of the same order of magnitude as in soil (column 11, Table n). 

Fig. 10. Leaf water potential and abaxial stomatal conductance (upper figure), and water potential and turgor of secondary and tertiary root tips (lower figure) of maize plants growing in 1 m deep soil columns, watered daily (A) or not watered after day 0(A). The roots were sampled from the upper 20 cm of the soil column. Plants were 20 days old at the beginning of the experimental period. Points are means s.e. Modified from Zhang Davies (1989).

Fig. 12. Relationships between root ABA content and bulk soil water content for maize plants growing in drying soil columns. Data are from Fig. 11, but do not include soil water contents less than 0.1 g cm in which many roots were non-living. Modified from Zhang Davies (1989).

Van der Meer JR, TNP Bosma, WP de Bruin, H Harms, C Holliger, HHM Rijnaarts, ME Tros, G Schraa, AJB Zehnder (1992) Versatility of soil column experiments to study biodegradation of halogenated compounds under environmental conditions. Biodegradation 3 265-284. 

Increased removal of phenanthrene from soil columns spiked with the rhamnolipid mixture synthesized by Pseudomonas aeruginosa UG2 has been demonstrated, and shown to depend both on the increased desorption of the substrate and on partitioning into micelles (Noordman et al. 1998). However, the addition of the biosurfactant from the same strain of Pseudomonas aeruginosa UG2 or of sodium dodecyl sulfate had no effect on the rate of biodegradation of anthracene and phenanthrene from a chronically contaminated soil. 

Surfactants have been widely used to reduce the interfacial tension between oil and soil, thus enhancing the efficiency of rinsing oil from soil. Numerous environmentally safe and relatively inexpensive surfactants are commercially available. Table 18.6 lists some surfactants and their chemical properties.74 The data in Table 18.6 are based on laboratory experimentation therefore, before selection, further field testing on their performance is recommended. The Texas Research Institute75 demonstrated that a mixture of anionic and nonionic surfactants resulted in contaminant recovery of up to 40%. A laboratory study showed that crude oil recovery was increased from less than 1% to 86%, and PCB recovery was increased from less than 1% to 68% when soil columns were flushed with an aqueous surfactant solution.74-76... 

The application system, called the biodrain, is installed within the treatment area. The biodrain aerates the soil column and any standing water. This cerates an aerobic environment in the pore spaces of the soil. Other gas mixtures can also be introduced to the soil column, such as the air/ methane mixtures used in the biodegradation of chlorinated organics. The treatment platforms can be placed in very dense configurations. International Environmental Technology claims that the cost of installation is low. 

From the hydrologic cycle temporal resolution of soil moisture surface, runoff, and groundwater recharge components, by inputting to the model the net infiltration rate into the soil column and... 

Soil Column Leaching. Glass tubing (diameter = 1 cm) was cut into 50 cm lengths, and one end was plugged with glass wool and Miracloth . Air dry soil (percent moisture = 2%, 1%, 4%. for Felton, Keeton, Prairie, respectively) was packed into the tubes to a depth of 30 cm. A small layer of white builders sand was then... 

Soil Column Leaching. The distribution of radioactivity from [ 1 C]butylate applied at 4.5 KG/HA and [1 l C]alachlor and [1 C] — metolachlor applied at 2.25 KG/HA and leached with 15 cm of water in Felton sand, is shown in Figure 4. Although all three herbicides are mobile in this soil type, butylate showed less mobility, with 59.6% of the applied raidoactivity found in the upper 10 cm of the column, while 28.4% and 24.3% of the applied 1 C was found in the upper 10 cm of the alachlor and metolachlor columns, respectively. 

TABLE V. Rf of Butylate, Alachlor, and Metolachlor in Various Soil Columns... 

Age column is given in years, rock column is portion of rock used in a foundation, fireplace or wall in square feet, height of ceiling in ieet. Area is in square feet. Blanks in furnace column indicate no use of furnace, tightness A is average, T is tight, D is drafty, as stated by the homeowner, soil column shows soil from granite bedrock in a foundation, fireplace or wall. Water column is radon concentration in pCi/1. 

Pillai SD, Pepper IL (1991) Transposon Tn5 as an identifiable marker in rhizobia survival and genetic stability of Tn5 mutant bean rhizobia under temperature stressed conditions in desert soils. Microbial Ecol 21 21-33 Pote J, Ceccherini MT, Van VT, Rosselli W, Wildi W, Simonet P, Vogel TM (2003) Fate and transport of antibiotic resistance genes in saturated soil columns. Eur J Soil Biol 39 65-71... 

Biodegradation unacclimated aerobic aqueous biodegradation t,/2 = 48-192 h, based on a soil column study in which aerobic groundwater was continuously percolated through quartz sand (Kappeler Wuhrmann 1978 Howard et al. 1991) t,/2(aq. anaerobic) = 192-768 h, based on unacclimated aqueous aerobic biodegradation half-life (Howard et al. 1991). 

Sediment desorption t,/2 = 38.5 d from sediment under conditions mimicking marine disposal (Zhang et al. 2000). Soil t,/2 = 295-2448 h, based on aerobic soil column test data (Kincannon Lin 1985 quoted, Howard et al. 1991) ... 

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