Hydrophobic organic contaminant

Phytostabilization Soils, sediments Metals and metalloids (As, Cd, Cr, Cu, Pb, Zn, U, Se) Hydrophobic organics (PAHs, PCBs, dioxins, furans, pentachlorophenol, DDT, dieldrin) Phreatophyte trees to transpire large amounts of water for hydraulic control Grasses with fibrous roots to stabilize soil erosion Dense root systems are needed to sorb/bind contaminants... 

Luthy RG, Aiken GR, Brusseau ML, Cunningham SD, Gschwend PM, Pignatello JJ, Reinhard M, Traina SJ, Weber WJ, Jr, Westall JC (1997) Sequestration of hydrophobic organic contaminants by geosorbents. Environ Sci Technol 31 3341-3347... 

Burgess RM, Terletskaya AV, Milyukin MV et al (2009) Concentration and distribution of hydrophobic organic contaminants and metals in the estuaries of Ukraine. Mar Pollut Bull 58 1103-1115... 

Huckins, J.N. Petty, J.D. Prest, H.F. Clark, R.C. Alvarez, D.A. Orazio, C.E. Lebo, J.A. Cranor, W.L. Johnson, B.T. 2002a, A Guide for the Use of Semipermeable Membrane Devices (SPMDs) as Samplers of Waterborne Hydrophobic Organic Contaminants Publication No. 4690 American Petroleum Institute (API) Washington, DC. 

Lefkovitz, L.F. Crecelius, E.A. Gilfcil, T.J. 1994, The Use of Semipermeable Membrane Devices to Predict Bioaccumulation of Hydrophobic Organic Contaminants. The 15 Annual meeting of Society of Environmental Toxicology and Chemistry, Denver, CO Abstract WE25. 

Although SPMDs concentrate a very wide range of hydrophobic organic compounds, they are not suitable for all environmental contaminants. Table 2.1 lists chemicals classes or selected compounds shown to concentrate in SPMDs, but is not all inclusive. 

DeVita and Crunkilton (1998) have examined QC associated with the use of SPMDs. The results of their study demonstrated that quality control measures applied to SPMD analysis met or surpassed conventional guidelines (EPA Method 610 for PAHs in water was used for this comparison) for precision and accuracy. This elevated level of data quality was achieved even though measurements of both overall precision and accuracy of SPMD data encompassed more steps (each with the potential for variability) than the conventional method. In summary, DeVita and Crunkilton (1998) found that QC measures could be used to validate data from the analysis of SPMDs used in the field. In view of the state of SPMD QC, it appears that the SPMD approach for monitoring hydrophobic organic contaminants is equivalent to some EPA-approved methods. 

Smer-Lauridsen, F. and Kjlholt, J. 2000, Identification of selected hydrophobic organic contaminants in wastewater with semipermeable membrane devices (SPMDs). Water Res. 34 3478—3482. 

Wang, Z. Wang, Y. Ma, M. Lu, Y. Huckins, J.N. 2002b, Use of triolein-SPMD to assess the bioconcentration processes of hydrophobic organic contaminants in file Huaihe River, China. Environ. Toxicol. Chem. 21 2378—2384. 

Crystalline salts of many organic acids and bases often have a maximum solubility in a mixture of water and water-miscible solvents. The ionic part of snch a molecule requires a strongly polar solvent, snch as water, to initiate dissociation. A mixture of water-miscible solvents hydrates and dissociates the ionic fraction of pollutants at a higher concentration than wonld either solvent alone. Therefore, from a practical point of view, the deliberate nse of a water-soluble solvent as a cosolvent in the formnlation of toxic organic chemicals can lead to an increased solnbility of hydrophobic organic contaminants in the aqueous phase and, conse-qnently, to a potential increase in their transport from land surface to groundwater. 

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... 

Contaminated bed sediments exist at numerous locations in the United States and around the world. These result mainly from past indiscriminate pollution of our aquatic environments and consist of freshwater and marine bodies including streams, lakes, wetlands, and estuaries. The bed sediments contain many hydrophobic organic compounds and metal ions that in the course of time act as sources of pollutants of the overlying aqueous phase. There are a number of transport pathways by which pollutants are transferred to the aqueous phase from contaminated sediments. One of the lesser known, but potentially important, modes of transport of pollutants from bed sediments is by diffusion and advection of contaminants associated with colloidal-size dissolved macromolecules in pore water. These colloids are measured in the aqueous phase as dissolved organic compounds (DOCs). (These are defined operationally as particles with a diameter smaller than 0.45 micrometer.)... 

Backhus, D. A., Colloids in Groundwater Laboratory and Field Studies of Their Influence on Hydrophobic Organic Contaminants, Ph.D. thesis, Massachusetts Institute of Technology, Cambridge, MA, 1990. 

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