Soil contamination

The phenoxy-herbicide, 2,4-D, has been successfully bioremediated in a soil contaminated with such a high level of the compound (710 ppm) that it... 

Soil. Composting of soils contaminated by high explosives is being carried out at the Umatilla Army Depot near Hermiston, Oregon (70). Soil from munitions washout lagoons is being treated iadoors ia compost rows of 2,000 m, and the estimated cost is less than one-third the estimated cost of iaciaeration. If this is successful, there are 30 similar sites on the National Priority List that could be treated ia a similar way. 

Phytoremediation is also being developed for dealing with soils contaminated with high levels of selenium in California again B.juncea seems to be particularly effective in accumulating the contaminant from soil, and all plants tested were more effective at removing selenate than selenite (92). This is an interesting contrast to bacterial systems, where selenite reduction is more commonly found than selenate reduction. 

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. 

PermeOx is also used to improve the bioremediation of soils contaminated with creosote or kerosene (see Bioremediation (Supplement)), to deodori2e sewage sludges and wastewater (see Odormodification), and to dechloriaate wastewater and effluents. A special formulation of calcium peroxide, made by FMC and sold ia the United States under the trademark Trap2ene, is used for removing metal ions from acidic waste streams such as coal ash leachate and acid mine drainage (see Wastes, industrial). 

Xanthates are used in a froth flotation process of soils contaminated with mercury. The soil to be treated is mn through hydrocyclones, and the slurries are flocculated, dewatered, and removed to a secure landfill. The effluent water is recycled. The process is suitable for treating industrial land sites contaminated with mercury droplets (115). 

Available Chlorine Test. The chlorine germicidal equivalent concentration test is a practical-type test. It is called a capacity test. Under practical conditions of use, a container of disinfectant might receive many soiled, contaminated instniments or other items to be disinfected. Eventually, the capacity of the disinfectant to serve its function would be overloaded due to reaction with the accumulated organic matter and organisms. The chlorine germicidal equivalent concentration test compares the load of a culture of bacteria that a concentration of a disinfectant will absorb and still kill bacteria, as compared to standard concentrations of sodium hypochlorite tested similarly. In the test, 10 successive additions of the test culture are added to each of 3 concentrations of the hypochlorite. One min after each addition a sample is transferred to the subculture medium and the next addition is made 1.5 min after the previous one. The disinfectant is then evaluated in a manner similar to the phenol coefficient test. For equivalence, the disinfectant must yield the same number of negative tubes as one of the chlorine standards. 

An essential part of the on-site visit is the physical inspection of the toller facility—the walk-through. It offers the opportunity to confirm interview responses, observe work practices, interview employees, and note general housekeeping, soil contamination and safety issues. 

Has any soil contamination been reported to regulatoiy agencies ... 

Is there any evidence of soil contamination at these facilities ... 

Important intermedia transfer mechanisms affecting soil contaminants include volatilization or resuspension to the atmosphere and biouptake by plants and soil organisms. These, in turn, introduce contaminants into the food chain. 

USATHAMA) completed a trial burn of explosive, contaminated soil in a rotary kiln (Noland, 1984). Soil contaminated from red and pink water lagoons was successfully burned. A transportable rotary kiln yrstem was set up. The technology by Therm-All, Inc., had been used in industry for destruction of solid wastes. The normal screw feed system was not used, due to fear of a soil explosion during the extruded plug feed process. Therefore, the soil was placed in combustible buckets and individually fed by a ram into the incinerator. The feed rate was 300 to 400 Ib/hr and the operational temperature was 1200° to 1600°F in the kiln and 1600° to 2000°F in the secondary chamber. 

Aitken MD, WT Stringfellow, RD Nagel, C Kazuga, S-H Chen (1998) Characteristics of phenanthrene-degrading bacteria isolated from soils contaminated with polycyclic aromatic hydrocarbons. Can J Microbiol 44 143-152. 

Cassidy DP, RL Irvine (1997) Biological treatment of a soil contaminated with diesel fuel using periodically operated slurry and solid phase reactors. Water Sci Technol 35(1) 185-192. 

Andersson BE, T Henrysson (1996) Accumulation and degradation of dead-end metabolites during treratment of soil contaminated with polycyclic aromatic hydrocarbons with five strains of white-rot fungi. Appl Microbiol Biotechnol 46 647-652. 

Wilson SS, KC Jones (1993) Bioremediation of soil contaminated with polynuclear aromatic hydrocarbons PAHs, a review. Environ Pollut 81 229-249. 

A number of substituted triazines are used as herbicides, and their biodegradation has been discussed in Chapter 10, Part 1. Treatment of soil contaminated with atrazine (2-chloro-4-(ethylamino)-6-isopropylamino-l,3,5-triazine) illustrated a number of significant features. Although the soil that was used had the potential for degradation, a laboratory experiment with Pseudomonas sp. strain ADP that had an established potential for atrazine degradation revealed important limitations. There was a substantial decline in the numbers of Pseudomonas sp. strain ADP and only limited mineralization. Supplementation with citrate or succinate increased the survival of the strain, and successful mineralization was dependent on the preservation of a carbon/nitrogen ratio >10 (Silva et al. 2004). The last would apply generally to substrates with a low C/N ratio such as triazines. 

Kaake RH, DJ Roberts, TO Stevens, RL Crawford, DL Crawford (1992) Bioremediation of soils contaminated with the herbicide 2-5ec-butyl-4,6-dinitrophenol (Dinoseb). Appl Environ Microbiol 58 1683-1689. 

Martin M, E Eerrer, R Alonso, J Eernandez (1995) Bioremediation of soil contaminated by propachlor using native bacteria. Int Biodet Biodeg 213-225. 

Silva E, AM Pialho, I Sa-Correia, RG Bums, LJ Shaw (2004) Combined bioaugmentation and biostimulation to cleanup soil contaminated with high concentrations of atrazine Environ Sci Technol 38 632-637. 

Trial sites should not be selected at locations where soil contamination with test substances could be anticipated or where similar types of agrochemicals have been used within 1 year. 

The diagnosis of endemic fungal infections is often prompted by a patient history of prolonged (subacute) infectious symptoms, travel or residence in an endemic area, and/or participation in activities that result in exposures to soil contaminated by endemic fungi. 

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