Geochemical controls on the distribution of total mercury and methylmercury in sediments and porewater from the Yangtze River Estuary to the East China Sea

Chen, Feng; Yang, Shouye; Yin, Daqiang; Wang, Rui

doi:10.1016/j.scitotenv.2023.164737

Cited by 7 publications

(3 citation statements)

References 62 publications

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“…To understand the formation of the high THg/TOC ratio in the high TOC variability section, the source of the DOM and Hg in the metal oxide‐OM association need to be constrained. The sediment at Site U1366 is rich in reactive Fe‐Mn oxides but low in THg (less than 7 ppb), indicating that Fe‐Mn oxides are not able to enrich DOM and Hg from seawater, probably due to their low concentrations of DOM (Alperin et al., 1999; Nebbioso & Piccolo, 2013) and Hg (Bowman et al., 2020; Cao et al., 2023; Covelli et al., 1999) compared to porewater. As a result, the DOM and Hg most probably migrated from neighboring sediment layers.…”

Section: Discussionmentioning

confidence: 99%

Coupling and Decoupling Between Sedimentary Mercury and Organic Carbon Preservation in the Oxygenated Marine Environment

Qu,

Zhong,

Liu

et al. 2024

Geochem Geophys Geosyst

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Mercury (Hg) enrichment relative to total organic carbon (TOC) in sedimentary records has been widely used as a volcanism proxy. However, the depositional and diagenetic effects on Hg burial are not well understood, limiting the reliability of the proxy. Here, we report a systematic investigation of Hg sedimentation under well‐oxygenated bottom water. Most of the studied cores show total mercury content (THg) to TOC ratio between 50 and 300 ppb/%, including northwest Pacific ODP Site 1208, East Equatorial Pacific ODP Sites 677 and 1241, the Antarctic Zone ODP Site 1094, and East China Sea sediment core EC2005. The consistent THg/TOC ratio confirms the strong coupling between Hg and particulate organic matter (POM) despite large differences in geographic locations, sedimentation rates, TOC content, POM sources, and early diagenetic environments. Nevertheless, the THg/TOC ratio is higher in sediments under well‐oxygenated bottom water than in those under oxygen‐depleted waters, probably as a result of a higher degree of organic matter degradation in oxygenated sediments during early diagenesis. The THg in the high TOC variability section at Site 1208 is abnormally high, resulting in decoupling between Hg and POM. Mercury in this section is still leachable by oxidizing solution and has a similar trend of variability with easily reducible iron content, implying that the metal oxide‐organic matter association might act as Hg bounding phase. We suggest that the enriched Hg is probably supplied by the neighboring high TOC sediment. Therefore, while THg/TOC > 300 ppb/% could be considered as distinct Hg enrichment in sedimentary records, the diagenetic mobilization effect should be first excluded as the possible cause as demonstrated by the records of site 1208. Our study therefore provides new insights into the Hg cycle in the modern ocean and the utilization of Hg enrichment as a volcanism proxy.

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Section: Discussionmentioning

confidence: 99%

Coupling and Decoupling Between Sedimentary Mercury and Organic Carbon Preservation in the Oxygenated Marine Environment

Qu,

Zhong,

Liu

et al. 2024

Geochem Geophys Geosyst

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“…Cd, Hg, Pb, and As are highly toxic pollutants that pose potential risk to biological organisms and even to human life [19,54,55]. Therefore, data simulation is required to estimate the anthropic influence on biological ecosystems and human existence.…”

Section: Estimation Of Sediments Qualitymentioning

confidence: 99%

Contamination Assessment of Toxic Elements in River Sediments from Baia Mare, Romania—Extreme Pollution from Mining Activities

Bereș,

Maftei,

Dill

et al. 2024

Minerals

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Sediment samples from the Săsar River and its main tributaries were analyzed for their potentially toxic elements at the site of the Romplumb metallurgical company and near the well-known Pb-Zn-Cu epithermal deposit of Baia Sprie located in the Neogene volcanic chain of the Eastern Carpathians, Romania. The average metal concentrations arranged in order of decreasing abundance are as follows (mg·kg−1): Mn (4098) > Zn (2093) > Pb (918) > Cu (489) > As (160) > Cr (37.51) > Ni (30.25) > Co (28.13) > Cd (9.72) > Hg (1.81). Several pollution indices were successfully used to assess the degree of contamination and ecological risk. The majority of sampling sites indicate high degrees of pollution, with two major hotspots identified. There are further sources, such as the Șuior (Pb-Zn-Au) and Săsar (Au-Ag) epithermal deposits, Cuprom company, and Bozânta tailing ponds, identified as contaminants. The Baia Mare mining district is causing a serious threat to the aquatic systems in the region, and it can be taken as a reference area for the human impact derived from the mining of mineral deposits of Au-Ag-Cu-Pb-Zn. It is imperative to reduce ecological risks and thereby protect the population living within this abandoned mining area.

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“…Consequently, although 145 sediment cores were used for global data comparison, 131 out of the 145 cores from the coastal oceans were selected for the calculation of Hg-AR. Although our estimates do not include the contribution of contaminated sites to the Hg burial in global coastal oceans due to the scarcity of data on the exact location and extent/magnitude of Hg contamination in marine sediments, we cannot neglect the influence of local contaminated hotspot regions on Hg accumulation and cycling in coastal zones (Cao et al, 2023). For example, Kocman et al (2013) estimated that the annual contribution of Hg from contaminated sites can account for 8% (67-165 Mg yr −1 ) of the total riverine flux to estuaries (1320-2760 Mg yr −1 ; Sunderland & Mason, 2007), highlighting the significant role of Hg releases from contaminated sites in the global Hg budget.…”

Section: Literature Data Set Compilationmentioning

confidence: 99%

Mercury Burial in Modern Sedimentary Systems of the East China Marginal Seas: The Role of Coastal Oceans in Global Mercury Cycling

Sun,

Hu,

Sun

et al. 2023

Global Biogeochemical Cycles

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Coastal oceans, the transition zones between terrestrial and oceanic systems, are susceptible to anthropogenic mercury (Hg) inputs and are regarded as critical dynamic interfaces of the global Hg cycle. However, the extent to which coastal oceans are accountable for sequestering Hg remains largely unknown owing to a lack of data on high‐resolution Hg accumulation in marine sediments. Synthesizing the results of this study (eight cores and 212 surface sediments) and the literature (three cores and 149 surface sediments), we provide a quantitative evaluation of the biogeochemical cycle of sedimentary Hg in the East China Marginal Seas (ECMS), including the response of the coastal marine sediments to anthropogenic disturbance as well as both human‐derived and natural Hg burial fluxes. We find a linear increase in Hg accumulation since the 1950s (2.0 ± 2.5% yr‐1) and a decline in Hg accumulation between 2010 and 2016. Modern burial fluxes of total and anthropogenic Hg in the ECMS (covering ∼4.8×105 km2 of sea surface) were estimated to be 89.1 ± 48.3 and 35.9 ± 33.1 Mg yr‐1, respectively. Using a compilation of 688 surface sediments and 131 sediment cores (819 samples in total) distributed globally in coastal oceans, we estimate that approximately 1,590 (range: 1,190–2,760) Mg yr‐1 (Method 1) and 540 (range: 310–960) Mg yr‐1 (Method 2) Hg are accumulated in coastal ocean regions. Our findings suggest that coastal oceans are likely the largest global marine sinks for Hg and play a dominant role in regulating the oceanic Hg cycle and budgets.

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Geochemical controls on the distribution of total mercury and methylmercury in sediments and porewater from the Yangtze River Estuary to the East China Sea

Cited by 7 publications

References 62 publications

Coupling and Decoupling Between Sedimentary Mercury and Organic Carbon Preservation in the Oxygenated Marine Environment

Coupling and Decoupling Between Sedimentary Mercury and Organic Carbon Preservation in the Oxygenated Marine Environment

Contamination Assessment of Toxic Elements in River Sediments from Baia Mare, Romania—Extreme Pollution from Mining Activities

Mercury Burial in Modern Sedimentary Systems of the East China Marginal Seas: The Role of Coastal Oceans in Global Mercury Cycling

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