Mercury Concentrations In Sediments Research Articles

Spatial and temporal variations in the pollution status and sources of mercury in the Jiaozhou bay

In the past few decades, mercury (Hg) discharged into the coastal bays of China has significantly increased; however, long-term trends regarding the pollution status and sources of Hg in these bays have yet to be clear. Focusing on this issue, surface sediments and core sediments were collected in the Jiaozhou Bay (JZB), a typical bay highly affected by human activities in China, to analyze the concentrations and stable isotopic composition of Hg. Total mercury (THg) concentrations in surface sediment varied from 7 to 163 ng/g, with higher levels located in the eastern JZB, possibly attributed to intensive industrial and population density. THg in sediment cores 14 and 20 displayed fluctuating increasing trends from 1936 to 2019, reflecting the deterioration of Hg pollution. In contrast, THg in sediment core 28 near the river mouth exhibited a declining trend, possibly due to the river dam construction. Using a stable isotope mixing model, contributions of various sources (atmospheric, riverine, and industrial emissions) to Hg in the JZB were estimated. The results showed that industrial emissions were the main source (over 50%) of mercury in the JZB in 2019. Sediment cores recorded an increase in industrial Hg due to early industrialization and Reform and Opening-up before 2000. In addition, sediment core 20 demonstrated a rise in the percentage of riverine Hg due to land reclamation at the bay's mouth during 2000–2007.

Organic matter, eutrophication, and increased mass accumulation rates in the Anthropocene are the main drivers of mercury concentrations and historical enrichment in Canadian lake sediments

AbstractMercury (Hg) contamination in the environment is a persistent issue as emissions from industry are ongoing and legacy cycling is prolonged. To quantify total mercury (total Hg) and methylmercury (MeHg) concentrations in lake sediments across a wide suite of temperate to subarctic lakes, measurements and modeling were conducted for 320 sites across Canada. Total Hg varied from 7 to 567 ng g−1 dry sediment with a mean (median) value of 148 (128) ng g−1 dry sediment, with lowest concentrations observed in eutrophic lakes of the Prairies and Boreal Plains. Average total Hg concentrations have increased twofold in contemporary sediments relative to their preindustrial pair. MeHg concentrations were generally low, with a mean of 0.8 ng g−1 dry sediment and this form representing on average 0.6% of the total contemporary mercury concentrations. Water column variables related to eutrophication were among the strongest predictors of contemporary total Hg, MeHg, and total Hg enrichment in the sediments. In lakes where sediment radiometric data were collected, contemporary total Hg accumulation rates were strongly related to longitude(+) and Hg atmospheric deposition(+). Latitude(−) and Hg atmospheric deposition(+) were the best predictors of MeHg accumulation rates. Chromophoric dissolved organic matter optical properties were key predictors of both total Hg concentrations and accumulation rates. Our work highlights the paramount importance of lake trophic state and the nature of organic matter as key predictors of lake sediment mercury metrics.

Catchment land use effect on mercury concentrations in lake sediments: A high-resolution study of Qinghai Lake

Mercury (Hg) contamination in aquatic environments presents a significant ecological and human health concern. This study explored the relationship between catchment land use and Hg concentrations within Qinghai Lake sediment, the largest lake in China, situated on the Qinghai-Tibet plateau. The study entailed detailed mapping of Hg sediment concentrations and a subsequent environmental risk assessment. Considering the complex nature of the plateau landform and surface vegetation, the study area was delineated at a 100 km radius centered on Qinghai Lake, which was divided into 30 sectors to quantify relationships between land use and the sediment Hg concentration. The results revealed a mean sediment Hg concentration of 29.91 μg/kg, which was elevated above the background level. Kendall's correlation analysis revealed significant but weak associations between sediment Hg concentrations and three land use types: grassland (rangeland and trees) (rs = 0.27, p < 0.05), crops (rs = −0.37, p < 0.05), and bare ground (rs = −0.25, p < 0.1), suggesting that growing areas of grassland correlated with higher Hg levels in the lake sediment, in contrast to bare ground or crops area, which correlated with lower Hg concentrations. Multiple linear regression models also observed weak negative relationships between bare ground and crops with sediment Hg concentration. This research methodology enhances our understanding of the impact of land use on Hg accumulation in lake sediments and underscores the need for integrated watershed management strategies to mitigate Hg pollution in Qinghai Lake.

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 concentrations in sediments and oysters in a temperate coastal zone: a comparison of farmed and wild varieties.

Oyster aquaculture has progressively increased to meet growing demands for seafood worldwide; however, its effects on methylmercury (MeHg) production in sediment and accumulation in oysters are largely unknown. In this study, total Hg (THg) and MeHg in sediments collected from aquaculture and reference sites and in farmed and wild oysters were measured and compared to explore potential factors that regulate MeHg production and bioaccumulation at the aquaculture sites. The results showed that the mean concentrations of THg and MeHg in varying sediment depths at the aquaculture site were 34 ± 4.1 ng g-1 and 16 ± 12 pg g-1, respectively. In comparison, the mean concentrations of THg and MeHg in sediments at the reference site were 25 ± 2.5 ng g-1 and 63 ± 28 pg g-1, respectively. While the MeHg/THg in the aquaculture sediments increased with organic carbon content, the slope of MeHg/THg versus organic carbon content was suppressed by high concentrations of dissolved sulfide in the pore water. Multiple parameters (total sulfur, total nitrogen and acid volatile sulfide in sediment, and dissolved sulfide in pore water) showed significant negative relationships with MeHg/THg in the sediment, and the total sulfur content in the sediment showed the highest inverse correlation factor with MeHg/THg (r = - 0.83). The mean concentrations of THg and MeHg in farmed oysters (mean weight 3.2 ± 1.5 g) were 36 ± 10 ng g-1 and 15 ± 6.7 ng g-1, respectively, while those in wild oysters (mean weight 0.92 ± 0.32 g) were 47 ± 9.9 ng g-1 and 15 ± 6.7 ng g-1, respectively. Concerning oysters of the same size range, THg and MeHg levels were higher in farmed oysters than in wild oysters despite the faster growth rate of farmed oysters, suggesting that the Hg content of food sources is more important than growth dilution rates in the control of Hg levels. The mean hazardous quotient for MeHg in farmed oyster was calculated as 0.044 ± 0.020, suggesting no expected health risk from farmed oyster consumption.

Distribution of selenium and mercury concentrations in sediments of Kagoshima Bay: can submarine volcanic activity affect the distribution of selenium in sediments?

Distribution of selenium and mercury concentrations in sediments of Kagoshima Bay: can submarine volcanic activity affect the distribution of selenium in sediments?

Trace metal load of two urban wetlands with varied catchment activities in Ghana.

This study compared Lead (Pb), Chromium (Cr), Copper (Cu), Zinc (Zn), Mercury (Hg), Arsenic (As) and Cadmium (Cd) concentrations in sediment, water, and biota at Vaughan Dam which receives limited sewage effluent discharge from residential areas, and Korle Lagoon which receives industrial effluents, electronic waste, garages-spill oil and a host of others in addition to residential sewage effluent discharge. Samples were analyzed with Atomic Absorption Spectrometer. The results showed that concentrations of trace metals were generally higher in the sediment, water, and plants from the Korle Lagoon but only Cu in the sediment of Korle Lagoon showed a significantly high concentration. The similarities in the rank orders of the metal concentrations together with the dominance of Zn and Pb in most compartments of the wetlands indicated major differences did not exist in the contaminant input to the two wetlands except electronic waste recycling and disposal that resulted in significantly high copper concentrations in the sediment of Korle Lagoon. No evidence of biomagnification was determined along the food chains of the Vaughan Dam and the Korle Lagoon for all the metals studied.The Tilapia zilli from Vaughan Dam, the only biota that is regularly consumed from the wetlands, had Cr, Cu, Pb, Cd, Hg, and As concentrations above FAO/WHO permissible limits and therefore pose a health risk to consumers.

Land use impact on mercury in sediments and macrophytes from a natural lake in the Brazilian savanna

Freshwater ecosystems are essential to human and wildlife survival. They harbor a wide biodiversity that contributes to ecosystem services. In the ecosystem of the Brazilian Savanna, anthropic activities related to environmental pollution that includes mercury (Hg) is of concern. We studied total mercury concentrations ([THg]) in bottom sediments and macrophytes to assess its short-term (2012 and 2019) impact on a natural lake. Temporal changes in [Hg] were assessed with the geoaccumulation index (Igeo) and the sediment quality guidelines (SQG). The land use index (LUI) was used to assess differences in anthropogenic activities and the Normalized Difference Aquatic Vegetation Index (NDAVI) was used to assess macrophyte biomass density. The bioaccumulation factor (BAF) was used to assess Hg accumulation in macrophytes relative to sediments. The LUI showed an increase in the intensity of agricultural activities in the vicinities of the lake. The NDAVI indicated an increase in the density of macrophytes in the evaluated period. The Igeo indicated that in all sampling sites, pollution levels in sediments increased in 2019 (Igeo > 0), with concentrations exceeding the SQG in 2019. In 2012, [THg] in sediments ranged from 20.7 to 74.6 ng g−1, and in 2019 they ranged from 129.1 to 318.2 ng g−1. In macrophytes, [THg] ranged from 14.0 to 42.1 ng g−1 in 2012, to 53.0 and 175.3 ng g−1 in 2019. [THg] in bottom sediments and macrophytes were significantly higher in the second collection period (p < 0.05). There was no significant difference in BAF values between the periods and no significant bioaccumulation in macrophytes (BAF <1). Our results demonstrated that the macrophytes are not sensitive indicators of Hg pollution in lentic environments of the Brazilian Savanna; however, the increased land use intensity (agriculture, automotive traffic, and urban infrastructure) could increase Hg accumulation in sediments and macrophytes in a short time interval.

Sediment mercury concentration of a subtropical mangrove wetland responded to Hong Kong-Shenzhen industrial development since the 1960s

Mercury (Hg) in coastal wetlands is of great concern due to its acute toxicity. We measured the total Hg content (THg) from a 210Pb-dated sediment core obtained from the Futian mangrove wetland in Shenzhen Bay, South China to explore the historical variation and possible sources. Our results extend the sediment THg record back to 1960 and reveal three distinct intervals. Interval I (1960–1974) has low and increasing THg values, averaging 83.0 μg/kg; Interval II (1975–1984) witnesses a remarkably increase, peaking in 1980 (261.6 μg/kg) then remaining elevated; Interval III (1985–2014) shows a steady reduction, averaging 118.4 μg/kg. The good correlation among THg, TOC, and Hg/TOC, and the downstream decrease in monitoring sediment THg consistently suggest that the bulk THg are mainly sourced from the Shenzhen River discharge. The different timing in industrial development attributes the elevated THg concentrations during 1975–1984 to Hong Kong industrial sewage pollution.

Volcanism intensity and associated climate-ocean-land dynamics during the Cryogenian interglaciation: Insights from mercury isotopes

The Cryogenian interglaciation (ca. 660 Ma to 650 Ma) was an interlude between the Sturtian glaciation (ca. 717 Ma to 660 Ma) and Marinoan glaciation (ca. 650 Ma to 635 Ma). Recent observations of anomalously high mercury (Hg) concentrations in Cryogenian interglacial sediments at basinal settings in the Nanhua Rift Basin, South China, imply that large volcanism can be a possible driving force of the Cryogenian interglaciation. To test this hypothesis and understand the potential linkage between large volcanism and climate-ocean-land dynamics during the Cryogenian interglaciation, we investigate mercury (Hg) concentrations and isotopic composition of Cryogenian interglacial sediments at shallow water (shelf/slope) settings in the Nanhua Rift Basin, South China. The basal Mn-bearing black shales show an increased pattern in Hg concentrations (318 to 4400 ppb) and Hg/TOC ratios (243 to 1730 ppb/wt%), and overall positive Δ199Hg values (0.00 to 0.10‰), suggesting increasing volcanic Hg input into the ocean via atmospheric Hg(II) deposition in the early Cryogenian interglaciation. The upper siltstone samples show a dramatic decrease in Hg concentrations (from 5110 to 459 ppb) and a drop of Δ199Hg values (from 0.04 to −0.05‰), suggesting weakened volcanism during the middle-late Cryogenian interglaciation. Combined with the analyses of major and trace elements proxies, we demonstrate that (1) greenhouse climate in the early Cryogenian interglaciation induced high oceanic productivity, high organic burial on the seafloor and high terrestrial sulfate input into the ocean, which favors the deposition of Mn-bearing black shales in the ocean; and (2) weakened volcanism and continued continental weathering exhausted atmospheric CO2 and drove the global climate to the Marinoan glaciation. This study, therefore, provides important insights into the climate-ocean-land dynamics during the Cryogenian interglaciation.

Mercury geochemistry of marine sediments from the eastern Laptev Sea: The spatial distribution, levels, and contamination assessment

Twenty-seven sediment samples from the eastern Laptev Sea were analyzed for mercury and total organic carbon as well as grain-size distribution. The average total mercury (THg) concentrations in sediments are 29 ± 14 μg kg−1. A significant correlation of THg content with total organic carbon and clay and silt fractions was shown. The 210Pb-dated sediment core was used to evaluate the contamination degree and flux of THg in sediments from the eastern Laptev Sea. The average sedimentation rate for the all dated intervals was 0.17 cm/year. The THg flux increased from 20 to 28 μg/m2/year in the period of 1892–1950 to 53–59 μg/m2/year in the modern period of 2011–2015. According to various indices, the ecological risk from THg in studied sediment was low.

Background concentrations Hg in lakes Khanty-Mansi Autonomous Area, Russia

The materials of the study: the background concentrations of mercury dissolved in water and precipitated in bottom sediments of the 95 lakes. Methods: a total of 332 samples of lake sediments and 37 samples of lake water were collected during the background ecological monitoring of petroleum deposit areas between 2007–2011. Results: The mean background concentration of mercury had values of 0.046±0.012 mg/kg and 0.025±0.014 mg/kg in lake bottom sediments and waters, respectively. The highest concentrations of Hg were found in the eluvial and transeluvial positions, the lowest – in superaqual landscapes. The highest concentration of Hg in lake bottom sediments was found in string bogs (ridge-hollow-pool complex bogs) and the lowest – in mineral soils. There is a general tendency to for an increase the concentration of mercury in the bottom sediments of lakes from the tundra zone through the northern taiga to the middle taiga subzone. However, the middle taiga was characterized by a significant (R = 0.4) increase in Hg concentrations in the bottom sediments from the south to the north due to an increase in the proportion of string bogs in the same direction. Dissolved mercury concentrations significantly (R=0.6) increased from the west to the east The assessment of seasonal dynamics of mercury contents showed that Hg concentrations in bottom sediments significantly increased during the winter.

Mercury in soil, sediment, and lake water in upland headwater catchments in Ireland

Mercury concentrations in the atmosphere, surface waters, and soils have increased beyond natural levels as a result of human activities, which poses a risk to human and environmental health. Ireland is situated on the western periphery of Europe, and it is generally assumed that environmental mercury is low but there is limited information on mercury within natural environments. In this study, the interlinkages in the concentration of mercury in soils, lake sediment, and lake water were investigated in remote upland acid-sensitive catchments influenced by low deposition of atmospheric mercury. Thirty-one upland lake catchments were sampled for topsoil, lake sediment, and lake water during 2017–2018. Total mercury (THg) concentrations in water (median 5.4 ng/L) and sediment (median 30 ng/g) were low, owing to the remote location of the lakes. In contrast, THg in catchment soil was relatively high for a background region (median: 240 ng/g), which was attributed to the high organic matter content of the soil (median 87%). The results suggest catchment soils are the dominant driver of variation in THg in lake water and sediment in upland regions in Ireland. Further, given that highly organic soils can obscure interlinkages within catchments, this study demonstrated the value of exploring mercury independent of the influence of organic matter, i.e., THg normalized by organic carbon. As global action (such as the Minamata Convention) decreases mercury emissions, legacy soil mercury may become a more important input to aquatic systems than atmospheric deposition, which makes the relationships between terrestrial catchments and their water bodies vital for our understanding of mercury cycling.

Mercury Concentrations in Water, Sediments, Soil, and Fish Around Ancestral Afro-Descendant Territories Impacted by Gold Mining in the Cauca Department, Colombia

Mercury Concentrations in Water, Sediments, Soil, and Fish Around Ancestral Afro-Descendant Territories Impacted by Gold Mining in the Cauca Department, Colombia

Mercury in the Environment Around Industrially Impacted Locations in India: A Mini-Review.

India is a major emitter of mercury to the environment. This mini-review condenses the information available since 2008 on mercury in air, soil, sediment, biota and human biomarkers near industrial locations. Information from eight regions was analyzed. More than 40% of studies did not report sufficient QA/QC information on analysis methods. Highest quality was observed for studies on human biomarkers, biota, and sediments, and the lowest on water quality. Concentrations of mercury in sediments (up to 3650µg/kg), human biomarkers (up to 31µg/g) and fish (up to 3µg/g) in the vicinity of coal-fired power plants and iron and steel were high in general, and sometimes comparable to or higher than the global guideline, screening or reference values. Overall, impacts of industrial activities on mercury pollution of surrounding environment were evident, and warrant a speedy assessment of other industrial areas and implementation of mitigation measures.

Mercury contamination of two e-waste recycling sites in Ghana: an investigation into mercury pollution at Dagomba Line (Kumasi) and Agbogbloshie (Accra).

This study investigated mercury pollution at two e-waste recycling sites in Ghana-Dagomba Line in Kumasi and Agbogbloshie in Accra. A total of 129 soil samples taken at 100m and 50m resolutions, respectively, for Dagomba Line and Agbogbloshie, were analysed for mercury using a Zeeman atomic absorption spectrometry. Mercury concentrations from the recycling sites (ranging from 0.11 to 7.57mg/kg Dagomba Line, and 0.01-4.36mg/kg at Agbogbloshie) were significantly higher than that of the surrounding areas (0.01-0.17mg/kg in Kumasi and 0.01-2.18mg/kg in Accra) and unpolluted control sites (0.05mg/kg in Kumasi and 0.02mg/kg in Accra). The dismantling sites at both locations had the highest mercury concentrations. Furthermore, the concentrations were significantly higher at the Dagomba Line site in Kumasi than at Agbogbloshie, even though the Dagomba Line site is relatively recent. The mercury concentrations at both sites exceeded the pollution prevention and abatement level of 0.1mg/kg. However, the estimated human health risk showed no potential human health effects. Moreover, the mercury concentrations in water and sediment (0.12-7.69ng/L and 0.02-0.28ng/L for Dagomba Line and Agbogbloshie, respectively) were below the US EPA standards. Findings from this study show that e-waste recycling can contaminate the topsoil with mercury, irrespective of the scale of the activity.

Sediment mercury concentration changes as a response to increased industrial activity in Coronel Bay, Chile

Among the main sources of atmospheric mercury emissions are thermoelectric plants that use coal to generate electricity. This heavy metal is transported by air from its origin to neighboring coastal areas, where it is deposited in the sediment record. This research evaluated the content and temporal distribution of Hg in the coastal sediments of Central Chile, Coronel Bay, industrialized zone with two operative thermoelectric plants, and Coliumo Bay, reference zone free of industry. To this end, sediment cores from the centers of the two bays were obtained. Laboratory results show that the greatest Hg contents were found in the surface strata of the Coronel Bay core, with concentrations up to an order of magnitude greater than those obtained in the same strata in Coliumo Bay. This increase in Hg concentration coincides with the beginning of industrial activity in Coronel, with greater concentrations observed from 2012 on, the year in which the industrial operation of two coal-fired thermoelectric plants on the bay began. Based on 210Pb activity and the relationships between Hg content and organic matter, it was established that the main pathway of Hg to sediment is atmospheric deposition, while Coliumo presented inputs that reflect local non anthropogenic sources.

Mercury (Hg) and methylmercury (MeHg) in sediment and biota: A case study in a lagoon in Central Italy

A quantification of total mercury (Hgtot) and methylmercury (MeHg) concentrations in sediment and mussels was carried out in the east basin of the Orbetello lagoon in order to assess their bioaccumulation potential. The sediment was sampled in four macroareas, mussels were transplanted in the same sites and collected after seven weeks. The results show that Hgtot concentrations in sediments exceeded (0.21–16.9 mg/kg dry weight (dw)) the environmental quality standard of the Italian legislation (0.3 mg/kg dw). The Hgtot concentration in mussels (0.050–0.324 mg/kg wet weight (ww)) does not exceed the limit values (0.5 mg/kg ww) of the European food legislation. The biota–sediment accumulation factors (BSAFs) derived for MeHg (80–306.7) and a biomagnification factor (BMF) greater than 1 for Hgtot demonstrate that in the lagoon, these compounds can be transferred in the upper levels of the trophic chain and pose a risk to human health.

Mercury levels in sediment, fish and macroinvertebrates of the Boroo River, northern Mongolia, under the legacy of gold mining.

Gold mining is currently one of the main anthropogenic sources of mercury in the environment. In this study, the total mercury content was measured in bottom sediments, benthic macroinvertebrates (mayfly larvae), and fish (Siberian dace) along the Boroo River in northern Mongolia. There was a gold recovery plant in the middle reaches of the river until the mid-twentieth century; an accident there in the 1950s caused a mercury spill. We found an increased content of mercury in measured ecosystem components near the plant compared to the upper reaches of the river. The mercury content in sediments varied from trace amounts in the upper Boroo to 2200 ng/g dry weight (dw) in the vicinity of the plant ruins. The mercury content in mayfly larvae ranged from 50 to 2940 ng/g dw and had a spatial pattern as sediments, with the highest concentrations near the plant. The mercury content in sediments was lower at the mouth of the Boroo River than near the plant, reflecting the lower boundary of the mercury spill. Maximum values of mercury content in fish muscle were found at the river's mouth and were several times higher than in other rivers of northern Mongolia. Median mercury content in muscles of dace from the lower Boroo in 2016 has doubled since studies in 2010-2012, which may be the result of current mercury releases from gold mining.

Spatio-temporal distribution of gross mercury contents in the bottom sediments of small lakes of the taiga zone

Abstract. The results of the study of the gross mercury content in the bottom sediments of small lakes in the taiga zone (humid sedimentogenesis) are summarized. It is shown that mercury concentrations in organomineral sediments correspond mainly to its contents in rocks of the upper continental crust (background values). In bottom sediments, mercury is adsorbed by organic matter, biogenic silica and layered silicates. The regularities of the vertical distribution of gross mercury in stratified sections of bottom sediments of lakes of the taiga zone, geographically located in different regions of Siberia and on the southeastern edge of the Baltic Shield, have been established.