Humic materials aquatic

According to Hatcher and co-authors47 the CP/MAS NMR technique opens up new means of distinguishing between various structural features of aquatic and ter-restric humic materials of rather old origin. They found, for instance that the aliphatic carbons of the humic substances in Holocene sediments, are dominant components suggesting an input of lipid-like materials. 

Plechanov, N. Josefsson, B. Dyrssen, D. Lundquist, K. Proc. Symp. Terrestrial and Aquatic Humic Materials, Chapel Hill, 1981. 

It is well established that important photochemical reactions are mediated by humic material in the aquatic environment (Zepp et al. 1981a,b), and that these are particularly signihcant for hydrophobic contaminants. Partial reductive dechlorination of the persistent insecticide mirex associated with... 

Perdue, E.M. Presented at the Symposium on Terrestrial and Aquatic Humic Materials, University of North Carolina, November, 1981. 

McCarthy, J.F., B.D. Jimenez, and T. Barbee. 1985. Effect of dissolved humic material on accumulation of polycyclic aromatic hydrocarbons structure-activity relationships. Aquat. Toxicol. 7 15-24. 

Bollag JM (1983) In Christman RF, Gjessing ET (eds) Aquatic and terrestrial humic materials. Ann Arbor Sci Publ, Ann Arbor, Michigan, p 33... 

Many of the PCBs found in the aquatic environment (e.g., in lakes and in the Arctic and Antarctic) have migrated via atmospheric dispersion of vapors [404-410]. Vaporization of PCBs from soil decreases as the amount of humic material in the solid phase increases due to mainly partitioning processes [381-390]. Griffin and Chian [363] note that vaporization of PCBs from suspensions of solids or humic acids is reduced by the presence of these materials. 

Experiments to identify disinfection by-products (DBFs) have been carried out using two different procedures. In the first, natural waters (e.g., river, lake) are reacted with the disinfectant, either in a pilot plant, an actual treatment plant, or in a controlled laboratory smdy. fii the second type of procedure, aquatic humic material is isolated and reacted with the disinfectant in purified water in a controlled laboratory study. This latter type of study is relevant because humic material is an important precursor of THMs and other DBFs. Aquatic humic material is present in nearly all natural waters, and isolated humic material reacts with disinfectants to produce most of the same DBFs found from natural waters. Because DBFs are typically formed at low levels (ng/L-pg/L), samples are usually concentrated to allow for DBF detection. Concentration methods that are commonly used include solid phase extraction (SFE), solid phase microextraction (SFME), liquid-liquid extraction, and XAD resin extraction (for larger quantities of water) [9]. 

Environmental applications of FIFFF have been carefully collected in a review by Gimbert et al. [35]. Separations of nanoparticles belong to the FIFFF tradition and this sector has recently found new, fully deserved impulse for microparticle separations. The FIFFF technique has been applied to analyze humic material and submicron Fe colloids. Coupled with ICP-MS, FIFFF has been applied to detect the major and trace element chemistry of aquatic colloids in groundwaters and to determine the trace element distribution in soil and compost-derived humic and colloidal fractions in municipal wastewater. Recently, the ICP-AES has also been proposed as a specific detector for FIFFF to analyze inorganic nanoparticles (Figure 12.12). 

An extraction method for isolating humic substances from water by using XAD-8 has been proposed by Thurman and Malcolm (9) (see box). Humic substances in natural waters represent almost the entire hydrophobic acid fraction. This method has been used to isolate 4.25 g of humic substances from 24,500 L of ground water from the Fox-hills-Laramie aquifer and to obtain 500 g of humic material from 10,400 L of the Suwannee River (Table II). The sample from the Suwannee River was collected as a reference sample of aquatic humic substances by the International Humic Substances Society. In both of the examples cited, a fc cutoff of 100 was used. 

R. F. Christman and E. Gjessing (eds.), Aquatic and Terrestrial Humic Materials , Ann Arbor Science, Ann Arbor,... 

In fresh water, silver may form complex ions with chlorides, ammonium (in areas of maximum biological activity), and sulfates form soluble organic compounds such as the acetate and the tartrate become adsorbed onto humic complexes and suspended particulates and become incorporated into, or adsorbed onto, aquatic biota (Boyle 1968). Where decaying animal and plant material are abundant, silver strongly precipitates as the sulfide or combines with humic materials (Smith and Carson 1977). 

Chiou, C.T., D.E. Kile, T.I. Brinton, R.L. Malcolme, J.A. Leenheer, and P. MacCarthy. 1987. A comparison of water solubility enhancements of organic solutes by aquatic humic materials and commercial humic acids. Environ. Sci. Technol. 21 1231-1234. 

Francko, D. A. 1986. Epilimnetic phosphorus cycling Influence of humic materials and iron on coexisting major mechanisms. Canadian Journal of Fisheries and Aquatic Sciences 43 302-310. 

Backlund, P. 1992. Degradation of aquatic humic material by ultraviolet light. Chemosphere 25 1869-1878. 

Hatcher, P. G., Breger, I. A., Dennis, L. W., and Maciel, G. E. (1983). Solid-state 13C-NMR of sedimentary humic substances New revelations on their chemical compostion. In Aquatic and Terrestrial Humic Materials, Christman, R. F., and Gjessing, E. T., eds., Ann Arbor Science, Ann Harbor, MI, pp. 37-81. 

Estimates of true MW variations in HS of different genesis can be derived from results reported by Perminova et al. (2003). Here a large suite of humic materials, isolated from different aquatic and terrestrial environments, were analyzed using standardized SEC conditions the same column packing (Toyopearl F1W50S) and mobile phase (0.028 mol liter-1 phosphate buffer at pH 6.8). Figure 13.4 summarizes results. 

Ultrafiltration (UF) is a technique that has been widely used for fractionation of HS on the basis of molecular size differences (Janos, 2003). Its application to quantify size and molecular weight characteristics of aquatic humic materials is reviewed in detail by Burba et al. (1998) and Guo and Santchi (2007). 

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