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Dissolved organic nitrogen (DON) has not received much attention by the drinking watercommunity despite the potential role of DON on disinfection byproduct (DBP) formation andspeciation, biostability of raw and finished water, and membrane fouling. The EuropeanCommunity directive has a maximum admissible concentration for org-N of 1 mg Kjeldhal-N/L(DON+NHsub4/subsup+/sup), but the US has no similar guidelines. Currently, there are no reports of DON fateduring water treatment. Furthermore, some chemicals added during water treatment (e.g.,polymers) contain organic nitrogen and their contribution to DON in finished water has largelybeen overlooked. As a first step in understanding the fate of DON during water treatment, thispaper provides evidence that some forms of DON are removed during alum coagulation.Over the past two decades marine scientists, limnologists, and ecologists have studied DON,offering several techniques for measuring DON concentrations and understanding DONoccurrence. DON is comprised of a broad spectrum of molecular weight compounds, includingamino acids, amides, heterocyclic-N, and lesser amounts of uncharacterized nitriles andnitrosamines (Westerhoff et al. 2002). This paper summarizes DON concentrations andDOC/DON ratios in over 14,000 surface waters based upon an analysis of USGS-NAWQAdatasets, which use a TKN method (ammonia + DON) with a TKN detection limit of 0.2 mgN/L.The median DON concentration was 0.34 mg-N/L, although approximately 30% of the sampleshad a TKN value of less than 0.2 mgN/L. Primary sources of DON in watersheds include:upstream wastewater discharges; infiltration and runoff of organic fertilizers from agriculturalareas; excretion of algae products in eutrophic waters; urban runoff; and, forest litter.DON concentrations in surface waters are commonly higher than groundwater levels. Despitethe information on DON sources, occurrence, and fate within watersheds, there has been nointerpretation of DON occurrence as related to the management of drinking water supplies. Includes 8 references, tables, figures.

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Edition: Vol. - No. Published: 11/02/2003 Number of Pages: 9File Size: 1 file , 290 KB