Different Mercury Species Partitioning and Distribution in the Water and Sediment of a Eutrophic Estuary in Northern Taiwan

Effects of hydrologic regimes on the loading and spatiotemporal variation of mercury in the microtidal river estuary

The potential effect of hydrological conditions on distribution and loadings of Hg species was investigated in the microtidal Hyeongsan River Estuary (HRE). Dissolved Hg (DHg) and dissolved methylmercury (DMeHg) from the creek receiving industrial wastes were effectively settled to sediment during the post-typhoon period, while persistent input from the Hg-contaminated creek without settling was observed during the dry periods. The event-based mean approach was applied to explore the hydrological effects on the annual flux of Hg. The largest inputs of DHg and particulate Hg (PHg) were found in the Hg-contaminated creek, and DHg input was higher in the dry than wet periods whereas PHg input was higher in the wet than dry periods. In sediment, Hg and MeHg concentrations decreased after the typhoon, attributed to erosion of surface sediments. Overall, the HRE serves as an effective sink of Hg that reduces the degree of Hg contamination in coastal water.

In Search of Mercury Lost from Sediments in a Previously Contaminated Coastal Area, Harboøre Tange, Denmark

Concentrations of mercury in sediment and benthic invertebrate fauna of Nissum Broad, North-western Jutland, Denmark were investigated. The western coast of Nissum Broad is Harboøre Tange, along which heavy mercury contamination - caused by discharge from production of mercury containing seed dressers in the 1950 and 1960s - was documented in the 1980s. Recent investigations showed marked decreases in mercury contamination in the near shore sediments along Harboøre Tange since the 1980s and the present investigation was initiated to learn if the loss of mercury from Harboøre Tange had led to an increased mercury contamination in the neighbouring marine area, Nissum Broad. Mercury concentrations in the surface sediment correlated with the content of organic matter and the slope of the regression is a good indicator for the degree of mercury contamination. Average mercury concentrations in the upper 5 cm of the sediments ranged between 0.9 and 71 ng g- 1 dry weight (dw) with only 1 station exceeding the Background Assessment Concentration of 70 ng g- 1 dw. Average mercury concentrations in blue mussels Mytilus edulis (169-260 ng g- 1 dw) and periwinkles Littorina littorea (66-203 ng g- 1 dw) exceeded those in uncontaminated areas and the Environmental Quality Standard of approximately 100 ng g- 1 dw. Present sediment mercury concentrations in Nissum Broad are approximately half of what they were in the 1980s, rendering it unlikely that mercury lost from Harboøre Tange has been deposited there. Sediment and organism concentrations did not show any correlation.

Mercury levels in an environmentally protected estuarine area in Northeast Brazil: partitioning in the water column and transport to the ocean

In this study, total Hg concentrations (HgT) were determined in the suspended particulate matter (SPM) and the dissolved fraction of the water column to evaluate their behavior through a gradient of physical-chemical parameters in a continuum between rivers and the Serinhaém River estuary of the Pratigi Environmental Protection Area, a pristine environment without point sources of Hg contamination, located in Northeast Brazil. Twelve points were sampled, forming a river-estuary transect, and two samplings were carried out (April and September 2019). Significant spatial and temporal effects were detected only for particulate HgT and not for dissolved HgT. Considering both samplings, the mean HgT concentrations in SPM were 1112 ± 824 and 44 ± 33 ng·g^-1 in the river and estuary, respectively. Also, HgT concentrations in the dissolved fraction (1.61 ± 0.61 ng·L^-1) were below the limits established by environmental agencies (CONAMA = 2 μg∙L^-1 and USEPA = 1.4 μg·L^-1). Salinity and SPM concentrations were important predictors of HgT in the water column (R² = 0.81, p < 0.0001; R² = 0.56, p < 0.0001, respectively). Mercury transport to the ocean through SPM was 2 kg∙year^-1, 4000 times greater than the dissolved fraction.

The geochemical and environmental characteristics of trace metals in surface sediments of the river estuarine mouths around the Taiwan Island and the Taiwan Strait

The trace metals species in surface sediments of the Taiwanese river estuarine mouths and the Taiwan Strait were examined by sequential extraction method. Based on the metal species present in sediments, trace metals can be divided into three groups: (1) Co, Cr, Fe, Ni and Zn; (2) Cu and Hg; and (3) Mn and Pb. The total concentrations of trace metals in the first two groups are dominated by the residual fraction. While, Cu and Hg their organic species also contributes a significant percentage and reduces the residual fraction portion. Lead and Mn are dominated by the labile fraction. The total metal concentrations in the analyzed sediments seem to be influenced by Fe oxides, TOC and grain size. The metals contamination status assessed by three environmental indices suggests that the analyzed sediments are minor contaminated by trace metals, with a few exceptions of Cu and Hg at some stations.

Multimedia Pollution Prevention of Mercury-Containing Waste and Articles: Case Study in Taiwan

In response to the Minamata Convention on Mercury, effective 16 August 2017, the Taiwan government in recent years started to implement the sustainable material management of mercury-containing waste and articles. This was completed by a cross-ministerial collaboration for preventing the adverse effects of mercury on human health and the environment, based on the multimedia approach. The legislative or regulatory frameworks on the control and prevention of mercury emissions and releases have been established in environmental distributions, including air, water, soil, waste, food, and article (or commodity). Therefore, the central authorities included the Environmental Protection Administration (EPA), Council of Agriculture (COA), Ministry of Health and Welfare (MOHW), Ministry of Economic Affairs (MOEA), and Ministry of Labor (MOL). Furthermore, the implementation plans covered the reduction in mercury-containing products by restricted use and bans on its use, remediation of soil and groundwater for mercury-pollution sites, control of stationary source emissions, environmental monitoring, and compulsory recovery of mercury from electronic waste such as waste lightings. A successful case study on the recovery of mercury from electronic waste using a thermal treatment, and its capture control by activated carbon, was also addressed in this work. Due to the effectiveness of source control in Taiwan, the annual reported amount of mercury emissions from the stationary air pollution sources indicated a decreasing trend from 1.989 metric tons in 2016 to 1.760 metric tons in 2019. More significantly, the ministerial collaboration in implementing the Convention in Taiwan also echoed the United Nations (UN) Agenda 2030 for sustainable development goals (SDGs).