Sediment normalising factors

The observed concentration ranges of TBT in sediment or SPM in Dutch open waters and 19 Dutch harbours are shown in Table 2. The highest observed TBT-Sn concentration in Dutch harbours was a factor 30 higher than the highest TBT-Sn concentrations in open waters. The lowest TBT concentrations were more or less in the same range. In order to normalise the sediment and suspended matter concentrations to water concentrations a value for the (organic carbon partition coefficient) needs to be estimated. From the distribution of measured sediment and... 

More often, no isosbestic point appears in a set of spectra of real samples. This can be explained by several factors as the occurrence of dilution or other physicochemical factors (sedimentation, precipitation, oxidation, etc.). However, in case of quality conservation (simple dilution, for example), a normalisation step can lead to the revelation of at least one isosbestic point in the resulting set of spectra. This isosbestic point is called hidden isosbestic point (HIP). 

Normalisation is usually achieved by relating the contaminant concentration with components of the sediment that represent its affinity for contaminants (so-called normalisers ). Normalisation can be achieved by calculating the concentration of a contaminant with respect to a specific grain-size fraction such as <2 am (clay), <20 J,m or <63 jam (OSPAR, 2002). Aluminium and lilhium can also be used as co-factors. 

Values of Henry s law constant k =plc, where p is the partial pressure of the solute in the gas above the solution and c is the concentration of the solute) is a quantity frequently apphed in the thermodynamic description of dilute aqueous solutions, which is used in environmental chemistry and atmospheric physics as a major criterion for describing air-water partitioning of solutes at near ambient conditions. It plays amajor role in evaluating the transport of pollutants between atmosphere and aquatic systems, rainwater and aerosols. The octanol-water partition coefficient is a dimensionless number defined as the ratio of the compound s concentration in a known volume of octan-l-ol (Cq) to its concentration in a known volume of water (c ) after the octan-l-ol and water have reached equihbrium. It has been found to be related to water solubility, soil/sediment absorption coefficients and bioconcentration factors of pollutants for aquatic life. The adsorption coefficient normalised to the organic carbon content of the soil (sediment) is a useful indicator of the binding capacity of... 

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