Tracing Organic Footprints from Industrial Effluent Discharge in Recalcitrant Riverine Chromophoric Dissolved Organic Matter

Abstract

Excitation-emission matrix fluorescence spectroscopy, combined with parallel factor analysis and measurements of UV absorption and dissolved organic carbon (DOC) concentrations, was used to trace the footprints of industrial effluents discharged into the lower Kishon River (Israel). The lower Kishon River typifies streams that are affected by seawater tidal intrusion and represents an extreme case of severe long-term pollution caused mainly by a variety of industrial effluents. The industrial effluents may contribute about 90%, in terms of biochemical oxygen demand, of the total organic carbon discharged into the lower Kishon River. Water samples were collected along the river, including the points of effluent discharge from industrial plants, between November 2005 and September 2006. Two types of fluorescent components characterized the fluorescence of the lower Kishon River water: component I corresponded to humic-like matter and component II spectrally resembled material known to be associated with biological productivity, but different from typical tryptophan-like fluorophore. These fluorescent components and other substances that absorbed light at 254 nm contributed to the DOC pool that resisted riverine microbial degradation under laboratory conditions, and that constitutes up to 70% of the overall riverine DOC. The variations in DOC concentration, absorbance at 254 nm, and concentration of humiclike matter (characterized by component I) correlated with the distance from the sea and the water electrical conductivity, and were linked to seawater tidal intrusion. The increased concentration of component II, as well as its enlarged fraction in the overall riverine DOC pool, was found to be associated with the location of major inputs of the industrial effluents. These findings support the use of this fluorescent component as an indicator of industrial pollution in such severely contaminated riverine systems.

Self-Organising Maps and Correlation Analysis as a Tool to Explore Patterns in Excitation-Emission Matrix Data Sets and to Discriminate Dissolved Organic Matter Fluorescence Components

“…Finally, C2 covers an area surrounding the previous protein-like spots, overlapping the region occupied by tryptophan [56] . This component has also been reported to reflect microbial activity, and has been used as an indicator of anthropogenic DOM inputs [58] – [60] .…”

Characterization of Fluorescent Dissolved Organic Matter in an Affected Pollution Raw Water Source using an Excitation-Emission Matrix and PARAFAC

“…Murphy et al (2006) suggested that the fluorescence characteristic of Compound-1 as an unknown compound and resembled contaminants in water. Previous studies (Borisover et al, 2011;D'Andrilli et al, 2019;Walker et al, 2009) have found that humic-like compounds were characterized at an excitation maximum of 370-390 nm and an emission maximum of 460-480 nm. Those characteristics closely resembled those found for compound-2 in this current study, suggesting compound-2 (C2) was likely representing humic from the terrestrial origin.…”

Characterization of Dissolved Organic Matter from Agricultural and Livestock Effluents: Implications for Water Quality Monitoring

“…The percentages of each fluorescent component of LEs were 38.44% (C1), 30.44% (C2), 20.30% (C3), and 11.02% (C4), and were mainly protein-like substances (~68%). Due to the high COD in the exogenous input LEs, microorganisms may break down humic-like DOM in both aerobic and anaerobic environments [ 16 , 42 ], resulting in the higher fluorescence intensity of protein-like substances (C1 and C2) in LE samples. We discovered increased amounts of C1 and C2 protein-like substances in the winter as well, since C1 and C2 in LEs are thought to be microbial byproducts and the fluctuation in their fluorescence intensity is connected to microbial metabolism.…”