Comparison of PARAFAC components of fluorescent dissolved and particular organic matter from two urbanized rivers.

Abstract

Excitation-emission matrix (EEM) fluorescence spectroscopy combined with parallel factor analysis (PARAFAC) and multivariable analysis were employed to compare components of dissolved (DOM) and particulate (POM) organic matter and to reveal their correlations with water quality in Baitapuhe River and Xihe River in Shenyang City of northeast China. Eighteen water samples in Baitapuhe River and 16 water samples in Xihe River were collected along a human impact gradient. The DOM concentrations in Baitapuhe River were lower than those in Xihe River, so were the POM concentrations. The DOM in Baitapuhe River mainly derived from livestock wastewater and domestic sewage, which had strong biodegradability. However, the DOM in Xihe River mainly originated from industrial wastewater, which exhibited weak biodegradability. Four PARAFAC components (C1 to C4) were extracted from the DOM and POM. C1 was defined as fulvic-like component, and C2 was assigned as microbial humic component. C3 and C4 were ubiquitous protein-like component, which were referred as tryptophan-like and tyrosine-like components, respectively. The C3 was representative for the DOM in Baitapuhe River. The C3 and C4 were the main fractions of the DOM in Xihe River across the centralized wastewater-discharge region, whereas the C2 was the major component across the dispersed wastewater-discharge region. POM was dominated by the C4 in both rivers. Latent factors of water quality included the DOM, DO, Chl a, NO3-N, and NH4-N in Baitapuhe River, but the latent factors contained DOM, DO, BOD5, and COD in Xihe River. Baitapuhe River was under the aerobic condition, but Xihe River was under the anaerobic condition.