Ratio of Color to Chemical Oxygen Demand as an Indicator of Quality of Dissolved Organic Matter in Surface Waters

摘要

The majority of surface waters contain significant amounts of dissolved organic matter (DOM). To assess the content of DOM, different parameters are used, such as color, chemical oxygen demand and total organic carbon (TOC). Those parameters give direct or indirect of the content of DOC, but they do not characterize its quality. The important parameter of DOM which defines its hydrophobic-hydrophilic balance is the content of aromatic carbon. It has been numerously shown [1] that the absorbance value at 254 nm normalized to mass concentration of DOM expressed on organic carbon (OC) basis (known as SUVA parameter) gives a good indirect estimate of aromaticity of DOM. In this study, we have hypothesized that a ratio of two bulk parameters traditionally used to characterize water quality such as color and chemical oxygen demand (COD) may serve as an analogue of SUVA in characterizing quality of DOM, nominally, of its aromaticity as well as of the contribution of humic matter into the total pool of DOM To prove this hypothesis, the existence of the relationship was tested between direct aromaticity estimates provided by ~(13)C NMR and values of color to COD parameters for a set of well characterized humic materials. The obtained relationship was further extended to aromaticity assessment of DOM present in the samples of medium and high colored surface waters