Groundwater, dissolved organic matter

Khan AT, Thomson MB (1990) Groundwater transport of hydrophobic organic compounds in the presence of dissolved organic matter. Environ Toxicol Chem 9 253-263... 

Recently, Burkhard (2000) reviewed contaminant sorption by dissolved organic matter. Using several hundreds of UCC-water partition coefficients (A doc) reported in these studies, he found that UCC-water partition coefficients for naturally occurring DOC (humic and fulvic acids, sediment pore water, soil pore water, groundwater, and surface water) was best described by... 

Lafrance, P., Marineau, L., Perreault, L., and Villenueve, J.-P. Effect of natural dissolved organic matter found in groundwater on soil adsorption and transport of pentachlorophenol. Environ. Sci. TechnoL, 28(13) 2314-2320, 1994. 

It would lie far beyond the aim of this chapter to introduce the state-of-the art concepts that have been developed to quantify the influence of colloids on transport and reaction of chemicals in an aquifer. Instead, a few effects will be discussed on a purely qualitative level. In general, the presence of colloidal particles, like dissolved organic matter (DOM), enhances the transport of chemicals in groundwater. Figure 25.8 gives a conceptual view of the relevant interaction mechanisms of colloids in saturated porous media. A simple model consists of just three phases, the dissolved (aqueous) phase, the colloid (carrier) phase, and the solid matrix (stationary) phase. The distribution of a chemical between the phases can be, as first step, described by an equilibrium relation as introduced in Section 23.2 to discuss the effect of colloids on the fate of polychlorinated biphenyls (PCBs) in Lake Superior (see Table 23.5). 

Synthesis of concentrations and fluxes of DOC and DON in precipitation, throughfall, and soil organic and mineral horizons are often reported in the published literature (Willey et al., 2000 Michalzik et al., 2001 Neff and Asner, 2001 Neff et al., 2002). Dissolved organic matter from these sources contributes DOM to groundwater and surface water. Leaf litter leachate is documented as a major source of DOC in the soil water of forested watersheds (Hongve, 1999) and in surface waters (Wetzel and Manny, 1972 McDowell and Fisher, 1976). However, specific quantitative allocation of DOC and DON from roots, leaf litter, and the forest floor in soil solution remains uncertain. 

Wallis, P. M. 1979. Sources, Transportation, and Utilization of Dissolved Organic Matter in Groundwater and Streams. Scientific Series No. 100. Kananaskis Centre for Environmental Research, University of Calgary. 

Leenheer, J. A., Nanny, M. A., and McIntyre, C. (2003). Terpenoids as major precursors of dissolved organic matter in landfill leachates, surface water, and groundwater. Environ. Sci. Technol. 37,2323-2331. 

Figure 8.6 Major sources of dissolved organic matter (DOM) to estuaries, primarily composed of riverine inputs, autochthonous production from algal and vascular plant sources, benthic fluxes, groundwater inputs, and exchange with adjacent coastal systems. (Modified from Hansell and Carlson, 2002.)...

Wallis P. M., Hynes H. B. N., and Fritz P. (1979) Sources, transportation, and utilization of dissolved organic matter in groundwater and streams. Sci. Ser. 100, Inland Waters Directorate, Water Quality Branch, Ottawa, Ont. 

The Stringfellow Superfund site in California poses analytical problems similar to those encountered with most waste sites across the United States and that may be best addressed via LC/MS based methods. Most of the organic compounds in aqueous leachates from this site cannot be characterized by GC/MS based methods. Analysis of Stringfellow bedrock groundwater shows that only 0.78% of the total dissolved organic materials are identifiable via purge and trap analysis (IQ). These are compounds such as acetone, trichloroethylene etc, whose physical properties are ideally suited for GC/MS separation and confirmation. Another 33% of the dissolved organic matter is characterized as "unknown", i.e., not extractable from the aqueous samples under any pH conditions and thus not analyzed via GC. Another 66% is 4-chlorobenzene sulfonic acid (PCBSA), an extremely polar and water soluble compound that is also not suitable for GC analysis. This compound, a waste product from DDT manufacture, is known to occur at this site because of the history of disposal of "sulfuric acid waste from industrial DDT synthesis. 

To complete the series of groundwater reference materials (see section 8.5), a separate project has been carried out, focusing on a range of trace elements and bromide in natural groundwater samples. In natural groundwaters, in addition to the relatively low concentrations of trace elements, the dissolved organic matter (DOM) is usually much... 

Baker, A. and Lamont-Black, J. (2001). Huorescence of dissolved organic matter as a natural tracer of groundwater. Groundwater, 39,745-750. 

Chen, Mi., Price, RM., Yamashita, Y., and Jaffe, R. (2010). Comparative study of dissolved organic matter from groundwater and surface water in the Horida coastal Everglades using multi-dimensional spectrofluorometry combined with multivariate statistics. Appl. Geochem., 25, 872-880. 

---