The spectral characteristics and biotoxicity of fractions obtained from two different DOM molecular weight fractionation methods

Dissolved organic matter (DOM) fractions with different molecular weights were prepared by ultrafiltration centrifuge tube and ultrafiltration cup, respectively. Under the two different DOM molecular weight fractionation methods, the characteristics of obtained fractions and their biotoxicity were explored, and their joint action mode were identified. DOM were obtained from municipal wastewater treatment plant effluent (defined as EfOM) and commercial natural humic acid (defined as SWR-NOM). The results showed that DOM fractions with different molecular weight obtained from the two fractionation methods had the same fluorescence peak. Humic-like substances were the main fluorescent dissolved organic matter (FDOM) in EfOM and SWR-NOM, accounting for 56% ~ 91% of FDOM. For the same DOM, the relative content of FDOM composition in different molecular weight components is basically consistent. The variation of SUVA254 and E2/E3 from different fractions obtained by ultrafiltration centrifuge tube was larger than that by ultrafiltration cup. For the luminescent bacteria acute toxicity, in the same molecular weight range, the luminescent bacteria toxicity value of DOM fractions obtained by ultrafiltration cup fractionation method was higher than that detected by ultrafiltration centrifuge tube fractionation method, but the acute toxicity of © 2021, Editorial Board of China Environmental Science. All right reserved.