Basic characterization of Norwegian NOM samples - Similarities and differences

Nine NOM (natural organic matter) samples, isolated by reverse osmosis (RO) , and nine NOM samples, concentrated by low-pressure, low-temperature evapo ration (EVA) from various origin in Norway, were characterized by different methods. The methods included elemental content of the freeze-dried sample s (C, H, N, and O), elemental content of the redissolved samples (DOC, Na, Ca, Cu, Fe, and Mn), specific spectral absorbance at lambda = 254 nm (A(254 nm)/DOC) acid at lambda = 436 nm (A(436 nm)/DOC), UV/Vis-spectra, specific fluorescence (excitation and emission spectra), proton capacity, Cu-comple xation capacity, ans content of hydrolysable amino acids and carbohydrates. In addition, chromatographic characterization by gel chromatography and re versed-phase chromatography was done. Studies on adsorption and flocculatio n abilities and the formation of trihalomethanes (THM) and organic halogens adsorbable on activated carbon (AOX) upon chlorination were also investiga ted. Comparison of the results showed that the samples were different accor ding to the origin of the sample, isolation procedure, and time of sampling . The differences are not the same for all parameters used. Standardized pr ocedures have to be applied to redissolve the organic material in water in order to compare data. For the samples investigated, it was shown that para meters like elemental analysis (WC ratio), the specific spectral absorption in the UV range, proton capacity, complexation capacity and anionic partic le charge, amount of hydrolysable amino acids and carbohydrates, adsorption behaviour on activated carbon, and the THM-FP are sensitive parameters to show differences concerning origin and isolation procedure. (C) 1999 Elsevi er Science Ltd.