Soil nutrient volatilization

The process of anaerobic biotransformation with steam injection is a technology for the in situ remediation of soils and groundwater contaminated with dense non-aqueous-phase liquids (DNAPLs). Using this approach for remediation, steam is injected into the soil to volatilize and remove DNAPLs, with the simultaneous introduction of nutrients. The resulting subsurface conditions are suitable for biotransformation of the dissolved phase, into compounds that are more easily removed by vapor and groundwater extraction. 

ORM 12] OrmeSo E., Fernandez C., Effect of soil nutrient on production and diversity of volatile terpenoids from plants , Current Bioactive Compounds, vol. 8, pp. 71-79, 2012. 

The atmosphere may be an important transport medium for many other trace elements. Lead and other metals associated with industrial activity are found in remote ice caps and sediments. The transport of iron in wind-blown soil may provide this nutrient to remote marine areas. There may be phosphorus in the form of phosphine, PH3, although the detection of volatile phosphorus has not been convincingly or extensively reported to date. 

Although many physiological and biochemical processes In plants are affected by various allelochemicals, In most Instances the details of the mechanism of action of a particular allelochemical have not been elucidated. Because soil mediates the transfer of most allelochemicals (except perhaps volatile compounds) from a donor to a receiver, plant roots are often the first tissues to contact an allelochemical. Thus, It Is not surprising that root growth and development are Inhibited In many Instances of allelopathy (1.-3) One of the primary physiological functions of plant roots Is the absorption of mineral nutrients. Therefore, It Is logical that the Influence of allelopathic Interactions on mineral absorption by plant roots has been Investigated. 

Although there is no doubt as to the importance of mycorrhizae in nutrient absorption, reviews on ion uptake have generally not considered it. Hatling et al. (143) made this same point more than 10 years ago. In addition, although phenolic acids inhibit phosphate (144, 145) and potassium (146) uptake, no work has examined the effects of these compounds on nutrient absorption of mycorrhizal associations. Since soil microorganisms produce the bulk of the volatile compounds emitted from soil, which are known to inhibit or stimulate fungal development (147-148), this group of compounds from microbial sources should receive more attention. 

Bioventing technology was developed by the U.S. EPA Risk Reduction Engineering Laboratory to treat soil contaminated by numerous industrial wastes, which is subjected to aerobic microbial degradation, especially to promote the degradation of polycyclic aromatic hydrocarbons.65 It uses a series of air injection probes, each of which is attached to a low-pressure air pump. The air pump operates at extremely low pressures to allow the inflow of oxygen without volatilization of contaminants. Additional additives such as ozone or nutrients may also be supplied to stimulate microbial growth.77... 

Biovault is a commercially available, nonproprietary, ex situ treatment for soil and sediment contaminated with chlorinated and nonchlorinated volatile organic compounds (CVOCs and VOCs). The basic biovault process is to promote the degradation of the existing soil contaminants in consolidated piles by stimulation of the indigenous (or augmented) microbial population. The process typically includes low-intensity aeration, moisture control, and supplementation with nutrients. 

The Dual Auger system is an in situ treatment for soils contaminated with volatile organic compounds (VOCs), chlorinated volatile organic compounds (CVOCs), and inorganics. This process uses specialized equipment to mix soil and inject reagents. The system can add nutrients to promote bioremediation, inject steam to volatilize contaminants, install zero-valent iron to promote chemical treatment, or add a pozzolanic slurry to stabilize the contaminants. The injection and mixing process effectively breaks down fluid and soil strata barriers. Mixing also eliminates pockets of contamination that would otherwise remain untreated. 

High concentrations of volatile organic compounds (VOCs) can be poisonous to bacteria. At sites with high concentrations, in situ air stripping should be used to reduce the VOC concentrations before attempting in situ bioremediation. Site evaluation should include as assessment of the levels of nutrients in the soil to determine whether an additional carbon source or oxidizing agent is needed. 

The climatic and weather conditions during growth are regarded as more important than the nature of the soil with regard to the volatile oil content. Reports indicate that the best oil yields are obtainable in cool, rather wet summers (Purseglove et al., 1981). The combined application of fertilizers N80, S12 and Zn2.5 yielded 1% essential oil content compared with 0.7% without nutrient application (Manure et al., 2000). 

---