Pesticide-contaminated soils using

Table 6. Remediation of Pesticides-Contaminated Soils Using Na/NHa in a...

Phillips, T.A., Belden, J.B., Henderson, K.L.D., and Coats, J.R. (2002) Phytoremediation of pesticide-contaminated soil using a mixture and individual prairie grasses. 224th ACS National Meeting, Boston, Massachusetts, August 2002. 

An LTTA system was used to remediate 41,431 tons of pesticide-contaminated soil at the Arlington Blending and Packaging Superfund site in Arlington, Tennessee. The total project cost was 5,586,376. This figure included 4,293,893 for capital 62,351 for operation and maintenance 633,528 for analysis, excavation, and waste disposal and 596,604 other project costs (D212340, p. 5 D21038Y, p. 57). 

Karthikeyan, R., L.C. Davis, L.E. Erickson, K. Al-Khatib, P.A. Kulakow, P.L. Barnes, S.L. Hutchinson, and A.A. Nurzhanova (2004). Potential for plant-based remediation of pesticide-contaminated soil and water using nontarget plants such as trees, shrubs, and grasses. Crit. Rev. Plant Sci., 23(1) 91-101. 

Nannipieri P, Bollag JM (1991) Use of enzymes to detoxify pesticide - contaminated soils and waters. J Environ Qual 20 510-517... 

Solid-phase extraction (SPE) using small, disposable cartridges, columns, or disks is employed for isolation and cleanup of pesticides from water and other samples prior to TLC analysis, especially using reversed-phase (RP) octa-decyl (C-18) bonded silica gel phases. Microwave-assisted extraction (MAE) is a time- and solvent-saving method for removing residues from samples such as soils. Supercritical fluid extraction (SEE) has been used for sample preparation in the screening of pesticide-contaminated soil by conventional TLC and automated multiple development (AMD). Ultrasonic solvent extraction (USE) and videodensitometry have been combined for quantification of pesticides in sod. Matrix solid-phase dispersion (MSPD) with TLC and GC has been used to determine diazinon and ethion in nuts. 

Blood was studied in a group of virtually healthy adolescents aged 14-17 from two localities in the Ukraine, where pesticide exposure differed by a factor of three, though the pesticide content in food products, drinking water, air and soil in the experimental zone was not higher than public health standards permitted. In Azerbaijan there was a difference of 100 times in the amounts of pesticides used in the experimental and control localities, while the pesticide contamination of elements of the environment and food products in the experimental zone was 2-50 times higher than acceptable levels [A97]. Table 3.6 shows the results. 

The problems relating to increased contamination levels and/or insufficient sensitivity may be overcome by using matrix-solid phase dispersion, MS detection in selected ion monitoring (SIM) mode, and/or large volume injection. An example of combined analysis that utilizes specific detection is shown in Fig. 2.6. It entails simultaneous analyses of PAHs, PCBs, chlorobenzene, and organochlorine pesticides in soil. 

In the past (prior to 1974), exposure of humans to heptachlor and heptachlor epoxide was directly related to the application of heptachlor as an insecticide. However, because of the persistence and bioaccumulation of heptachlor and heptachlor epoxide, exposure of the general population can occur through ingestion of contaminated food (especially cow s or maternal human milk), inhalation of vapors from contaminated soil and water, or direct contact with residual heptachlor from pesticide application. People whose homes have been treated may continue to be exposed to these chemicals in the air over long periods. Occupational exposure can occur in the manufacture of the chemical or from use of heptachlor to control fire ants. The most likely routes of exposure at hazardous waste sites are unknown. Heptachlor has been found infrequently in soil and groundwater at hazardous waste sites. Children who eat contaminated soil or people who obtain tap water from wells located near hazardous waste sites might be exposed to heptachlor. Also, since both compounds can volatilize from soil, people living near hazardous waste sites may be exposed to the compounds in the air. 

Johnston AE, Goulding KWT, Poulton PR (1986) Soil acidification during more than 100 years under permanent grassland and woodland at Rothamsted. Soil Use Manage 2 3-10 Kahn SU (1982) Bound pesticides residues in soil and plant. Residue Rev 84 1-25 Kan AT, Chen W, Tomson MB (2000) Desorption kinetics from neutral hydrophobic organic compounds from field contaminated sediment. Environ Pollution 108 81-89 Kang SH, Xing BS (2005) Phenanthrene sorption to sequentially extracted soil humic acids and humans. Environ Sci Technol 39 134-140... 

In 1981, a study was undertaken to determine whether the evaporation beds were functioning as originally Intended after 4 to 8 years of use. The major concern at that time was to determine If the pesticides were building up In the beds, and, If so, what could be done to correct the problem without the expense of physical removal of the contaminated soil to a Class I or II dumpslte. 

There may be other pesticide contaminants and ground water contamination sites yet to be discovered. Therefore, the 12 different pesticides found In a total of 18 different states, as listed In Table III, represents the minimum number of pesticides and their distribution. There have been several reports of plcloram In well water, most of them anecdotal. However, It cannot be substantiated that the contamination has been due to normal pesticide use and leaching throu the soil or due to spillage. 

Chapter 5 of the document reviews the UFs used by UK Government departments, agencies, and their advisory committees in human health risk assessment. Default values for UFs are provided in Table 3 in the UK document with the factors separated into four classes (1) animal-to-human factor, (2) human variability factor, (3) quality or quantity of data factor, and (4) severity of effect factor. The following chemical sectors are addressed food additives and contaminants, pesticides and biocides, air pollutants, drinking water contaminants, soil contaminants, consumer products and cosmetics, veterinary products, human medicines, medical devices, and industrial chemicals. 

Similarly, a GLP study on the fate of a pesticide should not be conducted using the same equipment as routine analysis of pesticides in soils. Stability studies must be set up in a way that routine work in the lab will not contaminant the test materials. 

The B S Research, Inc., B S Achieve-B S Industrial technology uses microorganisms (B S Industrial) with emulsifier and nutrients (B S Achieve) to treat contaminated soil and water. According to the technology developer, the technology degrades hydrocarbons, chlorinated solvents, polychlorinated biphenyls (PCBs), fertilizers, pesticides, and other hazardous organic compounds. 

KAL con s thermal units are applicable to treatment of hydrocarbon-contaminated soils but may not be used to remediate soils contaminated with polychlorinated biphenyls (PCBs), radioactive isotopes, or dioxins. Pesticides and herbicides can be treated by low-temperature thermal desorption, but special permitting is required and may be difficult to obtain. 

The desorption and vapor extraction system (DAVES) uses a low-temperature fluidized bed to remove volatile and semivolatile organics such as polychlorinated biphenyls (PCBs), polynuclear aromatic compounds (PAHs), pentachlorophenol (PCP), volatile inorganics (tetraethyl lead), and some pesticides from soil, sludge, and sediment. The process generally treats waste containing less than 10% total organic contaminants and 30 to 95% solids. The process does not treat nonvolatile inorganic contaminants such as metals. 

The technology can be used in any type of soil, including low-permeability clays. According to the vendor, this technology can be used to treat polychlorinated biphenyls (PCBs), dioxins, chlorinated solvents, pesticides, and herbicides. The thermal blanket technology has been demonstrated to remediate PCB-contaminated soil to a level of 2 ppm. 

Supercritical carbon dioxide effectively extracts the nonpolar compounds from aU soil types. The extraction of more polar compounds, such as chlo-rophenols and some pesticides requires that a polar compound, such as a short-chain alcohol is added to the carbon dioxide. Supercritical carbon dioxide extraction is used by environmental analysis laboratories as a more efficient, occupationally more acceptable method for analyzing contaminated soils (Laitinen et al., 1994). 

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