Why CODMn Is Not Suitable for Assessing NOM Concentration in Source Waters

AWWA water science Pub Date : 2025-07-20 DOI:10.1002/aws2.70026

Jana Naceradska, Eva Tobolkova, Jan Haild, Lenka Pivokonska, Martin Pivokonsky

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Abstract

Total organic carbon (TOC) and permanganate chemical oxygen demand (COD_Mn) are the most commonly employed methods to determine the amount of natural organic matter (NOM) in raw and drinking water. However, the usage of COD_Mn is questionable due to its variable degrees of oxidation for different types of organics. Our study investigates the ratio of COD_Mn to TOC in source waters with diverse NOM compositions characterized by specific UV absorbance (SUVA) and total organic nitrogen (TON). Herein, mountainous water sources with high amounts of humic substances (high SUVA, low TON) exhibit approximately 1.8–2.5 times higher COD_Mn values than lowland algae-laden sources (low SUVA, high TON) despite having the same TOC values. The determination of COD_Mn, therefore, can give misleading information about the amount of organics in waters with different NOM character and underestimate the NOM concentration in lowland algae-laden water sources, which could have implications for drinking water quality.

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为什么CODMn不适合评估水源中NOM的浓度

总有机碳（TOC）和高锰酸盐化学需氧量（CODMn）是测定原水和饮用水中天然有机质（NOM）含量最常用的方法。然而，CODMn的使用是有问题的，因为它对不同类型的有机物的氧化程度不同。本研究以特定紫外吸收（SUVA）和总有机氮（TON）为特征，研究了不同NOM组成的水源水体中CODMn与TOC的比例。其中，尽管具有相同的TOC值，但具有大量腐殖质物质（高SUVA，低TON）的山区水源的CODMn值比低地藻类源（低SUVA，高TON）高约1.8-2.5倍。因此，CODMn的测定可能会对具有不同NOM特征的水体中有机物的数量提供误导性信息，并低估了低地藻类丰富的水源中NOM的浓度，这可能对饮用水质量产生影响。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

AWWA water science

CiteScore

4.40

自引率

0.00%

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