Seasonal Variation of Terrigenous Polycyclic Aromatic Hydrocarbons along the Marginal Seas of China: Input, Phase Partitioning, and Ocean-Current Transport

Abstract

To study the spatial distributions and seasonal differences of concentrations, source identification, and phase partitioning of polycyclic aromatic hydrocarbons (PAHs) in surface water, intensive sampling was carried out along the marginal seas of China in four seasons. In the northern South China Sea (SCS), the highest PAH levels occurred in the summer (July to August) and autumn (October to November). In the East China Sea (ECS) and the Yellow Sea, the highest occurred in the summer (August) and winter (December). In all areas, the lowest PAH levels were found in the spring (May to June). The estimated mass inventory of PAHs in the surface water (0-5 m) of the northern SCS and ECS accounted for less than 8% of PAHs outflow into the offshore environment. That showed the consistent seasonal variation with PAHs levels. Land- and ocean-based emissions, surface runoff, and the open seawater dilution were the most important environmental factors influencing the seasonal heterogeneity and the spatial distributions of PAH in the surface water. The decline of observed organic carbon normalized partition coefficients in the four seasons was probably affected by the presence of submicrometer-sized soot particles accompanying the PAH outflow from China.

RETRACTED: Temporal Variations of Polycyclic Aromatic Hydrocarbons in the Seawater at Tsukumo Bay, Noto Peninsula, Japan, during 2014–2018

“…The annual mean Σ 13 PAH concentration increased from 0.40 ng L −1 in 2014 to 1.17 ng L −1 in 2017, plateauing at 1.06-1.17 ng L −1 , during 2017-2018, with a mean of 0.89 ng L −1 over the entire period. The mean Σ 13 PAH concentration in the Tsukumo Bay measured during the present study was two orders of magnitude lower than the Σ 10 PAH and Σ 15 PAH concentrations measured in the continental shelf waters of the East China Sea during 2005-2006 and 2009-2011 when Σ 10 PAH and Σ 15 PAH levels of 70-120 ng L −1 (mean 87 ng L −1 ) [12] and 10-150 ng L −1 (mean 54 ng L −1 ) [11], respectively, were recorded. PAH contamination in the Tsukumo Bay was also an order of magnitude lower than that in the Southeastern Japan Sea in 2008 (Σ 13 PAH = 6.8-14 ng L −1 ; mean 9.4 ng L −1 [16]) and the northwestern coastal region of the Japan Sea in 2010 (Σ 13 PAH = 7.4-10.2 ng L −1 ; mean 7.9 ng L −1 [17]).…”

“…The East China Sea is one of the largest sources of PAHs in the Western Pacific, including the Japan Sea [10,11], with the continental shelf water there containing relatively high Σ 10 PAH concentrations of 70-120 ng L −1 , during 2005-2006 [12] and Σ 15 PAH concentrations of 10-150 ng L −1 , during 2009-2011 [11]. The highest Σ 15 PAHs levels in the East China Sea occur in summer, during 2009-2011 (80 ± 32 ng L −1 ) owing to the high volume of surface runoff and strong soil erosion transported by the Yangtze River; with winter levels during 2009-2011 (67 ± 25 ng L −1 ) reflecting the input of anthropogenic pyrolytic PAHs from industrial coal and domestic firewood combustion delivered by the prevailing northwest wind from mainland China [11]. As shown in Inoue et al (2010) [22], the contribution of the East China Sea continental shelf water in the East Channel of Tsushima Strait, the entrance to the Japan Sea, increases from summer to autumn and decreases during winter and spring.…”

“…Total PAH fluxes into the East China Sea are estimated to be 243 t year −1 through river flow (Yangtze River, 232 t year −1 ; Qiantang River, 11 t year −1 [8]) and~150 t year −1 through atmospheric deposition [9,10], with~38% (152 t year −1 ) of the total being retained in marine sediments [10]. The Yangtze River estuarine-inner shelf in the East China Sea is, thus, considered to be one of the largest reservoirs and sources of PAHs in the Western Pacific [10,11], with its continental shelf water containing Σ 10 PAHs (total concentrations of 10 particulate and dissolved PAHs) of 70-120 ng L −1 [12]. Investigation of the environmental behavior of PAHs in the East Asian marginal seas is essential in assessing the ecological risk of anthropogenic PAHs, since these seas are one of the most fertile fishing ground.…”

From headwaters to estuary: distribution, sources, and ecological risk of polycyclic aromatic hydrocarbons in an intensively human-impacted river, China

“…5, there was a significant correlation (p < 0.05) between the measured log K oc and log K ow (octanol water partition coefficient) of PAHs in Xiaoqing River section. Other studies have also found this relationship in particulate water partition (Ya et al 2017). The measured values log K oc were lower than the theoretical values, indicating that the chemical partition between dissolved and particulate phase in the aquatic system is not balanced yet.…”

Spatiotemporal Variation of Cold Eddies in the Upwelling Zone off Northeastern Taiwan Revealed by the Geostationary Satellite Imagery of Ocean Color and Sea Surface Temperature

“…It is a north-flowing ocean current that transports heat and organic matter on the west side of the North Pacific Ocean and eventually merges with the easterly drift of the North Pacific Current. Therefore, the Kuroshio current plays a significant role in transporting and exchanging of heat and organic matter in the East China Sea and the northern part of the South China Sea [56][57][58]. For example, a strong mixing of the Kuroshio current and coastal waters has been reported in the China Continental Shelf of the East China Sea where the water is deeper than 50 m [59].…”