Tipping, Edward and Corbishley, H.T. and Koprivnjak, J.-F. and Lapworth, D.J. and Miller, M.P. and Vincent, C.D. and Hamilton-Taylor, John (2009) Quantification of natural DOM from UV absorption. Environmental Chemistry, 6 (6). pp. 472-476. ISSN 1448-2517
Abstract
The precise simulation of ultraviolet absorption by 23 contrasting surface-water DOM samples was achieved with a model based on two components, one absorbing light strongly (A) and the other weakly (B). The parameterised model can be used to predict [DOC] inwater samples simply from absorbance values at twowavelengths,while information on DOM quality is provided by the calculated fractionation into A and B. The model was tested by predicting [DOC] for a separate dataset obtained by combining results for 12 samples each from surface waters in the UK, Canada and the USA, and from UK groundwaters. A close correlation (R2 =0.997) was obtained, with only slight underestimation of the true [DOC]. The proportions of components A and B varied considerably among the sites, which explains why precise prediction of [DOC] from absorbance data at a single wavelength was not possible. When the model was applied to samples collected from river locations in a heterogeneousUKcatchment with areas of industry and high human population, [DOC] was underestimated in many cases, which may indicate the presence of non-absorbing pollutant DOM.