Natural organic matter-water systems partitioning

Partitioning in Natural Organic Matter-Water Systems, may write, by analogy to Equation 6,... 

However, LFERs of the type of Eq. 3-56 may not only be used as predictive tools they may also serve other purposes. For example, they may be very helpful to check reported experimental data for consistency (i.e., to detect experimental errors). They may also enable us to discover unexpected partitioning behavior of a given compound, for example, if a compound is an outlier, but, based on its structure, is expected to fit the LFER. Finally, as will be discussed in various other chapters, if for a given set of model compounds such LFERs have been established for various two-phase systems, where one of the phases is not very well characterized (e.g., various natural organic matter-water systems, different atmospheric particle-air systems), the slopes a of the respective LFERs may yield some important information on the nature of the phases considered (e.g., to detect differences or similarities among the phases). 

The second difference between the laboratory tests and exposure under realistic environmental conditions is that in the laboratory exposure concentrations are maintained, or the ecotoxicological endpoints are adjusted to account for any decline. Under natural conditions a combination of the pyrethroids tendency to partition rapidly and extensively to organic matter, coupled with their susceptibility to degradation in aquatic systems where algae and macrophytes are present [13,14], means their overall dissipation rate from the water phase is generally relatively rapid. Water column dissipation half-lives tend to be around 1 day (see Sect. 5). This behavior means that it is unlikely that aquatic organisms will be exposed to pyrethroids in the water phase for prolonged periods in natural water bodies. 

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