Transport and fluxes of terrestrial polycyclic aromatic hydrocarbons in a small mountain river and submarine canyon system

Abstract

Polycyclic aromatic hydrocarbon (PAH) concentrations in the Gaoping River were investigated in the wet and dry seasons. PAH characteristics allowed us to trace the particulate matter transported in a river-sea system containing a small mountain river, continental shelf, and submarine canyon. PAH signatures of the Gaoping River showed that particles were rapidly transported from the high mountain to the Gaoping coastal areas in the wet season, even arriving at the deep ocean via the Gaoping Submarine Canyon. By contrast, in the dry season, the particles were delivered quite slowly and included mostly pyrogenic contaminants. The annual riverine flux estimates for PAHs were 2241 kg in the Gaoping river-sea system. Only 18.0 kg were associated with the dissolved phase; the rest was bound onto particles. The fluxes caused by typhoons and their effects accounted for 20.2% of the dissolved and 68.4% of the particulate PAH fluxes from the river. Normalized partition coefficients for organic carbon suggested that PAHs were rigid on the particles. Distinct source characteristics were evident for PAHs on riverine suspended particles and coastal surface sediments: the particles in the wet season (as background signals) were similar to petrogenic sources, whereas the particles in the dry season had characteristics of coal burning and vehicular emissions. The sediments in the northwestern shelf were similar to pyrogenic sources (including vehicular emissions and coal and biomass burning), whereas the sediments in the canyon and southeastern shelf arose from mixed sources, although some diesel signature was also evident.

Removal of anthracene in water by MIL-88(Fe), NH2-MIL-88(Fe), and mixed-MIL-88(Fe) metal–organic frameworks

“…When present in water, it does not undergo photodegradation due to its high lipophilic nature. 5 It is highly resistant to biodegradation compared to other PAHs such as phenanthrene and pyrene, 6 and can easily enter the food chain through water. 7,8 PAHs have been linked to serious diseases such as cancer (particularly lung cancer), cardiovascular disorders, and defects in reproductive system, among others.…”

Polycyclic aromatic hydrocarbons in estuarine sediments as a consequence of the mine tailings remobilization and transport in the Rio Doce basin

“…Polycyclic aromatic hydrocarbons can be divided roughly into two classes: pyrogenic and petrogenic, from combustion and petrochemicals, respectively. Two ratios most often used to determine the source of PAHs in river water are ANT/(PHE + ANT) and FLU/(FLU + PYR) (Chen et al, 2020; Guo et al, 2007; Lin et al, 2016; Mohammed et al, 2021). Other ratios widely applied in different environments are IcdP/(IcdP + BghiP) and BaA/(BaA + CHY; Ashayeri et al, 2018; Neira et al, 2017; Wang et al, 2020; Yunker et al, 2002).…”

Response of the benthic biomass-size structure to a high-energy submarine canyon

“…Therefore, the entire length of the GPSC is characterized by its meandering, V-shaped, and entrenched thalweg with deep-cutting outer bends (Figure 1). These erosive features are believed to be maintained by turbidity currents triggered by river flooding (Lin et al, 2013;Lin et al, 2016), internal tides (Wang et al, 2008;Lee et al, 2009;Chiou et al, 2011), groundwater discharges (Su et al, 2012), and sediment slumping (Hsu et al, 2008;Su et al, 2012;Gavey et al, 2017). The energy of internal tides is estimated to be 3-7 times greater than that in the well-known Monterey Canyon of similar shape and size (Lee et al, 2009), with a bottom current velocity ranging between 1.4-1.7 m/s and increasing toward the canyon head (Wang et al, 2008).…”