Characteristics of dissolved organic matter (DOM) and relationship with dissolved mercury in Xiaoqing River-Laizhou Bay estuary, Bohai Sea, China

Abstract

a b s t r a c tBecause of heterogeneous properties, dissolved organic matter (DOM) is known to control the environmental fate of a variety of organic pollutants and trace metals in aquatic systems. Here we report absorptive and fluorescence properties of DOM, in concurrence with concentrations of dissolved mercury (Hg), along the Xiaoqing River-Laizhou Bay estuary system located in the Bohai Sea of China. A mixing model consisting of the two end-members terrestrial and aquatic DOM demonstrated that terrestrial signatures decreased significantly from the river into the estuary. Quasi-conservative mixing behavior of DOM sources suggests that the variations in the average DOM composition were governed by physical processes (e.g., dilution) rather than by new production and/or degradation processes. In contrast to some previous studies of river-estuary systems, the Xiaoqing River-Laizhou Bay estuary system displayed a non-significant correlation between DOM and Hg quantities. Based on this and the variation of Hg concentration along the salinity gradient, we concluded that Hg showed a non-conservative mixing behavior of suggested end-member sources. Thus, rather than mixing, Hg concentration variations seemed to be controlled by biogeochemical processes.

The Response of Catchment Ecosystems in Eutrophic Agricultural Reservoirs to Water Quality Management Using DOM Fluorescence

“…The metabolic activities of microorganisms and algae were relatively strong, and the results are consistent with the β:α values (mean value range of the β:α ratio of the five reservoirs was 0.96-1.34) ( Table 5), indicating primarily endogenous DOM sources of the reservoirs [32]. Compared with previous studies, it is evident that most endogenous DOM inputs were replenished mainly by surface runoff, but some lakes were also affected by industrial and agricultural sewage, domestic wastewater, and rivers entering the lake (Table 5) [48][49][50][51][52]. In Albufera des Grau Lake, Valloxen Lake, and Lumpen Lake [49,51], which are surrounded by farmland and forests, FI values ranged from 1.28 to 1.40, suggesting that the DOM contained contributions from terrestrial sources.…”

“…The indexes of FI, HIX, and BIX further and significantly explained the characteristics and sources of DOM [48][49][50][51][52]. The FI values of the reservoirs classified according to pollution sources were ranked as YD and BR (livestock, FI ≈ 1.81) < BA and HJ (living, FI ≈ 1.84) < NJ (farmland, FI = 1.98) (Figure 3a).…”

“…This finding supports endogenous pollution sources of the reservoirs. The HIX mean value of the five reservoirs was 2.87 ± 0.64 (less than 4), and the BIX mean value of the five reservoirs was 1.17 ± 0.16 (more than 1), which further indicate that higher relative endogenous contributions of DOM showed in the eutrophic reservoirs ( Figure 3) [45][46][47][48][49]. The metabolic activities of microorganisms and algae were relatively strong, and the results are consistent with the β:α values (mean value range of the β:α ratio of the five reservoirs was 0.96-1.34) ( Table 5), indicating primarily endogenous DOM sources of the reservoirs [32].…”

In situ fluorescence measurements of dissolved organic matter: A review

“…The increase of global economy and population, together with the effects of climate change put a great stress on water resources, increasing the number and quantity of pollutants and threatening to destabilise natural dissolved organic matter (DOM) cycles and composition (Kellerman et al, 2014;Lipczynska-Kochany, 2018;Pagano et al, 2014). Five decades of research have shown that fluorescence spectroscopy has the potential to characterise aquatic DOM, from natural or anthropogenic sources (Christman and Arnquist, 1969;Hu et al, 2017;Hudson et al, 2007;Jiang et al, 2017;Laane, 1982;Smart et al, 1976). It has been extensively used for cost-effective, reagentless and reliable measurement of water quality from various environments Chen et al, 2015;Chong et al, 2013;Mihalevich et al, 2017;Pesant et al, 2015).…”

Quantitative Estimation of Cr and Pd in <I>Heteropneustes Fossilis</I> Fish due to Absorption from Tannery Waste Water

“…The major culprit of water pollution is toxic metals and in many forms, it is easily intruding into water. It has been established by research that toxic metals from antifouling paint particles [1], microcystin-LR (MCLR) and copper (Cu) [2], dietary or water borne cadmium (Cd) [3], silver (Ag) nanoparticles from antibacterial agents [4], nickel (Ni) and zinc (Zn) from coal mining [5] are polluting aquatic environment and ultimately, it is harming the dependents of water such marine life even human beings. Recently, it has been investigated the Ni toxicity in marine and estuarine invertebrates and fish [6], mercury (Hg) concentration in sharks [7], toxicity of Cu and chromium (Cr) nanoparticles to Daphnia magna [8].…”