Vertical profile, contamination assessment of mercury and arsenic in sediment cores from typical intertidal zones of China

Abstract

The vertical profiles, contamination levels, and potential ecological risks of mercury and arsenic were studied from the sediment cores of seven typical intertidal zones, including the Liaohe River Estuary, the Jianhe River Estuary, the Dagu River Estuary, Yancheng Shoal, the Dongtan Yangtze River Estuary, Hangzhou Bay, and the Pearl River Estuary. Marine sediment quality standards, the threshold effect level (TEL), and the probable effect level (PEL) were used as guidelines to evaluate sediment quality. In addition, the geo-accumulation index (I) and potential ecological risk index ([Formula: see text]) were used to assess contamination and potential ecological risks from mercury and arsenic. The results showed that the Pearl River Estuary was moderately polluted by mercury and represented a high potential ecological risk, while other areas were uncontaminated or mildly contaminated with low or moderate potential ecological risks. The Pearl River Estuary was mildly polluted by arsenic and represented a mild potential ecological risk, while other areas were unpolluted and also posed a mild potential ecological risk.

Mercury enrichment in anthrosols and adjacent coastal sediments at a Classic Maya site, Marco Gonzalez, Belize

“…THg concentrations in MG wetland samples are greater than sediment concentrations found in mangrove margins of contemporary urban waste dumps in Brazil (Machado et al, 2002; Silva et al, 2003) and tropical coastal lagoons receiving urban runoff (Acevedo‐Figueroa et al, 2006; Conrad & Sanders, 2017) (Table 4b). Similarly, THg values in sediment cores from MG are comparable and higher than THg measured in wetland, estuarine–lagoon muds linked to atmospheric deposition and waste from historical industrial and artisanal sources (Benoit, 2018; Conrad & Sanders, 2017; Elbaz‐Poulichet et al, 2011; Fitzgerald et al, 2018; Laperche et al, 2014; Rood et al, 1995; Wang et al, 2018) (Table 4). With regards trace metal waste, MG might be considered to have acted as a leaky landfill during and post‐occupation, contributing to long‐term legacy contamination of surrounding coastal wetland habitats.…”

“…Coastal wetland sediment sequences have been used extensively to investigate historical human activity, using mercury and trace metal sediment records, at both global and local scales (Conrad & Sanders, 2017; Gan et al, 2013; O'Shea et al, 2018; Rosales‐Hoz et al, 2003; Silva et al, 2003; Wang et al, 2018). Mercury in coastal wetland and estuarine sediments is of significant interest due to its presence from often unambiguous historical industrial sources and its pervasive accumulation through food webs (Cotin et al, 2011; Elbaz‐Poulichet et al, 2011; Kongchum et al, 2006; Mitchell & Gilmour, 2008; O'Driscoll et al, 2011).…”