Distribution of mercury in coastal marine sediments of China: Sources and transport

Abstract

a b s t r a c tA total of 220 surface sediments and eight sediment cores were analyzed to study the distribution and transport of Hg in Chinese marginal seas. Spatial distribution showed a general offshore decreasing trend towards the outer continental shelf. Vertical profiles of sediment cores displayed a general increasing trend from bottom to surface layers. Coastal land-based discharges and river-derived inputs are probably the main sources of Hg in coastal sediments of China seas, while TOC, pH, ocean currents and sediment characteristics could play important roles in the transport and spatial distribution of Hg in sediment. The influence of TOC on Hg concentration is more significant than that of pH. The mud deposits on the coastal shelves are main sinks of Hg in the region. The results showed that sedimentary Hg was affected by regional anthropogenic activities and riverine runoffs, and was also influenced by long-range atmospheric transport and ocean current circulations.

Mercury dynamics in macroinvertebrates in relation to environmental factors in a highly impacted tropical estuary: Buenaventura Bay, Colombian Pacific

“…This pattern was confirmed when reviewing Tukey's test: in the sediments of the IE station, there was a higher concentration of T-Hg, while the strongest dilution occurred at ME. This gradient has also been reported in other estuaries (Cogua et al 2012;Meng et al 2014;Shoham-Frider et al 2007). Taken together, the sediment Hg dynamics suggested an anthropogenic origin of Hg, which would enter the estuary through the rivers and runoff during the rainy season.…”

Distribution of eight heavy metals in the inner shelf sediments of East China Sea: Risk assessments and sources analysis

“…Cores DH1-1 and DH5-1 are located in coastal clay area with a water depth of 52.0 and 54.8 m, respectively; cores Figure 1. Maps showing the regional sea circulation patterns and surface sediment particle size distribution (modified after Hu et al 2012;Zhu et al 2012;Meng et al 2014) in the ECS (a), and locations of the surface and core sampling sites in inner shelf of the ECS (b). Note that BS: Bohai Sea; YS: Yellow Sea; SCS: South China Sea; TWC: Taiwan Warm Current; CDW: Changjiang (i.e., Yangtze River) Dilute Water; ZFCC: Zhejiang-Fujian Coastal Current; YSCC: Yellow Sea Coastal Current; and JCC: Jiangsu Coastal Current.…”

“…A lot of research on HMs in inner shelf of the ECS (including the Yangtze River Estuary (YRE)) has been reported (Fang et al 2009;Pan and Wang 2012;Duan et al 2014;Wang et al 2015;Han et al 2017;Zhang, Sun, and Xu 2020). Although the concentrations, distributions, and sources of Hg have been studied in the ECS (Shi et al 2005;Fang and Chen 2010;Meng et al 2014Meng et al , 2019Kim et al 2018;Cheng et al 2019;Sun et al 2020), the levels, distribution characteristics, and ecological risks of other elements (e.g., zinc (Zn), chromium (Cr), nickel (Ni), lead (Pb), copper (Cu), arsenic (As), cadmium (Cd)) in inner shelf of the ECS are not well understood. The lack of this information restrains evaluations of toxic metal pollution in the ECS.…”

Seasonal changes of mercury speciation in the coastal sediments

“…In their study, Hg TOT concentrations in sandy sediments collected close to the shore did not exceed 10 ng g −1 and consisted in 12 to 60% of the residual fractions. Meng et al (2014) in China and Hwang et al (2016) in South Korea measured Mercury concentrations in coastal sediments obtaining concentration ranges 7-398 and 8-120 ng g −1 (respectively). Both authors point out the dependencies between mercury accumulation and sediment grain size (the lowest concentrations-around 10 ng g −1 and less-are always noted in sandy sediments) and occurrence of local anthropogenic contamination sources.…”