Mercury Concentrations In Water Research Articles

The Analysis of Mercury Concentrations of Water in Gold Mining Environment at Poboya, East Palu Subdistrict, Palu, Central Sulawesi Province

Gold mining activities influence the environment, mainly the aquatic environment, due to the heavy metal and mercury detected in settling pond and river waters. Based on laboratory analysis, it is known that Mercury concentrations in settling pond water of inlet, transition, and outlet zones respectively are 0.075 mg/L, 0.042 mg/L, and 0.027 mg/L. These are shown that mercury concentration in water was not passed Government Regulation of the Minister of Environment No. 202 the year 2004 about quality standards of liquid waste, which said that the standard is 0.005 mg/L. The Heavy metal concentrations, especially mercury in river water at 1, 2, 3, 4, and 5 stations respectively, are 0.004 mg/L, 0.009 mg/L, 0.050 mg/L, and 0.006 mg/L, which do not meet the government regulation of water quality standard 0.001 mg/L.

Assessment of Mercury Concentrations in Water and Fish Tissue Analysis in Kaw Lake, Oklahoma, 2022

The Kaw Nation has been collecting water, sediment, and fish samples from Kaw Lake and upper Arkansas River from 2007 to present to examine the concentrations of Mercury and other heavy metals to protect the health of the tribal members. Kaw Lake is in the North-Central part of Oklahoma. Kaw Lake is a permanent water body constructed in 1976 by the Army of Corps of Engineers. The Lake is consistently fed by the Arkansas River and other tributaries as runoff coming all the way from Colorado through Kansas to Kaw Lake of Oklahoma. The Lake has a surface area of 26.64 square miles (69 km2) and shoreline of 168 miles (270 km) with a total drainage area of 56,345 square miles (145,393 km2) and an average water depth of 8 meters. The water and fish samples were collected from 7 sites of Kaw Lake, once in a month and the fish samples once in a year during summertime, early July to end of July. The fish samples focused on 5 sport, predator, and bottom dwelling species of large consumable size, greater than 200 mm length and 560 grams weight. The five fish sampled were Catfish, White bass, Largemouth and Smallmouth bass, Black and White crappie. The fish and water samples were sent to Accurate Environmental Labs for detailed analysis. Predator species were analyzed as fillet and the bottom dwellings as a whole fish using EPA Method 7471A-M. Mercury from Water and Fish Tissue Samples were analyzed by Atomic Fluorescence Spectrometry. The laboratory analysis indicated that all the Mercury concentration in the fish samples except in Blue Catfish and Spotted Bass fall below the Maximum Contaminant Level (MCL) of 0.5 mg/kg.

HEAVY METALS IN WATER, SEDIMENT AND IN SOME SELECTED FISH SPECIES OF THE ENNORE AND CHENNAI FISHERIES HARBOUR, CHENNAI, TAMIL NADU

Mercury and arsenic are the toxic heavy metals found in water, sediment and in different species of fish tissue, Rastrelliger kanagurta(Indian Mackerel), Nemipterus spp., (threadfin beam), Parapenaeopsis Maxillipedo (shrimp), Metapenaeus dobsoni (shrimp), Perna sp. (bivalve), Sepia sp.(Cephalopod-cuttlefish) and Loligo sp.(Cephalopod–squid) of the Chennai, Ennore estuary. The water, sediment and fish tissues were analysed for mercury and arsenic using standard procedure in Atomic Absorption Spectrophotometry. The maximum mercury concentration in water is 0.02ppb±0.01, in sediment is 0.30 ppb±0.01 and in different fish tissue species in Rastrelliger Kanagurta, 0.25ppb±0.06, Nemipterus spp., 0.54ppb±0.06, Parapenaeopsis Maxilli - pedo 0.58ppb±0.06, Metapenaeus dobsoni, 0.34 ppb±0.06, Perna sp., 0.61ppb±0.06 and Sepia sp. 0.72ppb±0.06 and Loligo sp.,Cephalopod-squid, 0.38 ppb±0.06 in the first quarter. Among the fish species selected for the study during Apr-June’09, the lowest mercury content is in Rastrelliger kanagurta (Indian Mackerel), 0.35ppb±0.11 followed by Metapenaeus dobsoni,0.68ppb±0.11, Sepia spp., 0.76ppb±0.11, Loligo sp. (Cephalopod squid), 0.78 ppb±0.11 and Nemipterus spp. (threadfin bream), 1.29ppb±0.11 during second quarter. The percentage increase in mercury during first quarter is 64.67% from lowest to highest. The percentage increase in mercury during second quarter is 55.99% from lowest to highest. The percentage increase in mercury content in µg/g (ppb) was 80.27% from lowest to highest. The metal concentration in tissues µg/g (ppb) ranged between 0.26-1.29µg/g (ppb) in mercury. Among the fish species selected for study for arsenic during JanMar’09, the lowest arsenic content is in Rastrelliger Kanagurta (Indian Mack erel), 3.85ppb±8.22 followed by Nemipterus spp. (threadfin bream), 6.10ppb±8.22, Loligo sp., 26.09ppb±8.22, Metapenaeopsis Maxillipedo (shrimp), 34.72 ppb±8.22, Parapenaeopsis Maxi - millipedo (shrimp), 43.84ppb±8.22, Sepia spp., 52.09ppb±8.22 and Perna sp. (bivalve) 60.13 ppb±8.22 in the first quarter. Among the fish species selected for the study during Apr-June’09, the lowest arsenic content is in Rastrelliger kanagurta (Indrai Mackerel), 4.35ppb±7.88 followed by Nemipterus spp. (threadfin bream), 13.12ppb±7.88, Metapenaeus dobsoni (shrimp) 14.92 ppb± 7.88, Sepia sp., (Cephalopod cuttlefish), 18.74ppb±7.88 and Loligo sp. (Cephalopod –squid) 45.09 ppb±7.88 in the second quarter. The percentage increase in arsenic during first quarter is 93.58%. The percentage increase in arsenic during second quarter is 90.34%. The percentage increase in arsenic content value in µg/g(ppb) was 93.58%. The metal concentration in tissues, µg/g (ppb) ranged between 3.85-60.13µg/g(ppb). The lowest mercury in tissue was found in the species Rastrelliger Kanagurta was 0.25µg/g (ppb)±0.06 and in arsenic it was 3.85µg/g, (ppb) ±8.22 the highest mercury in tissue was found in the Nemipterus sp., 1.29µg/g(ppb)±0.11, the highest arsenic was found in 60.13µg/g (ppb)±7.88 in Perna sp.(bivalve).

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

Differences in Mercury Concentrations in Water and Hydrobionts of the Crimean Saline Lakes: Does Only Salinity Matter?

Of significant scientific and public concern is the high toxicity, significant bioaccumulation, and magnified concentration within the food web of mercury (Hg). Hg content both dissolved and in suspended forms in water as well as in biomass of different hydrobiont taxa was studied in 18 saline lakes in Crimea from 2012 to 2021. The impact of different factors (salinity, seasonality, anthropogenic activities, geological background, etc.) was analyzed. The generalization of data for all lakes showed that the average concentration of Hg in dissolved form was 129 ng L−1, varying over a wide range. The content of Hg in total suspended substrates was an average of 151 ng L−1, and the total content of Hg in lake water averaged 291 ng L−1. Geological background and anthropogenic activities can determine the total Hg content in lakes. In most lakes, a significant positive correlation was noted between the concentration of one, two, or all three indicators of Hg content and the month of the year, with indicators increasing from winter through to autumn. When analyzing the entire data array, a significant positive correlation was found between the concentration of the suspended form of Hg and salinity; such correlation between the concentration of the dissolved form of Hg and salinity was absent. The highest average Hg concentrations in biomasses were noted in Artemia and were the lowest in plants. Geological background and human activity contribute to high Hg content in lakes. Hydrobionts can significantly influence the distribution and behavior of Hg, being an important factor of its cycle in the lakes.

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.

Assessment of Natural Zeolite Clinoptilolite for Remediation of Mercury-Contaminated Environment

The soil at ancient roasting sites in the surroundings of the Idrija mine (Slovenia) is highly contaminated with mercury. To assess the impact of mercury on groundwater by infiltration and find an eco-friendly remediation method, the leaching of mercury from the soil containing 1347 mg Hg/kg, followed by sorption of the total leached mercury on cost-effective natural zeolite (NZ) clinoptilolite, was performed. The leaching of soil in ultrapure water of pHo = 3.00–11.46 after 24 h resulted in the total leached mercury concentration in the range 0.33–17.43 µg/L. Much higher concentrations (136.9–488.0 µg/L) were determined after the first few hours of leaching and were high above the maximum permissible level in water for human consumption. The NZ showed very good sorption of the total leached mercury, with a maximum removal efficiency of 94.2%. The leaching of mercury in presence of the NZ resulted in a significant decrease of the total leached mercury (1.9–20.3 µg/L compared to 12.8–42.2 µg/L), with removal efficiencies up to 90.5%, indicating immobilization of mercury species. The NZ has a great potential for economically viable remediation of mercury-contaminated environment. However, efforts should be made in the further study of mercury leachability to reduce the mercury concentration in water to acceptable levels.

Total mercury pathways from artisanal and small-scale gold mining in Sukabumi using system dynamics model

Artisanal and small-scale gold mining (ASGM) has been operated in Sukabumi District, West Java, Indonesia, for more than two decades. ASGM uses mercury in a ball mill gold ore processing, and the waste is released into the environment during and after this process. Previous studies have found that mercury-contaminated water, air, sediments, soil, and aquatic biota. This study aimed to predict and analyze total mercury pathways from ASGM in the air, water, sediment, fish, and humans using a system dynamics model. The results showed that the total mercury concentration in water was low and still meets the standard, while the total mercury concentration in sediment had already exceeded the standard. Biomagnification occurred to plankton feeder fish and top predator fish, but still below the level of tolerance mercury. Mercury levels in top predator fish and humans take a long time to exceed the standard (77 and 67 months after entering the body, respectively). The percentage error of 17.67% compared to the experimental data showed that the prediction of the developed system dynamics model is acceptable. Therefore, the model can be used to predict the total mercury pathways in the environment, especially in the ASGM area.

The potential use of Octolasmis spp. parasites in mud crabs Scylla spp. as a bioindicator for mercury pollution

Abstract. Nur I, Aris EA, Yusnaini Y, Beavis S. 2021. The potential use of Octolasmis spp. parasites in mud crabs Scylla spp. as a bioindicator for mercury pollution. Biodiversitas 22: 3764-3772. Artisanal small-scale gold mining and the use of mercury is widespread across Indonesia, often characterized by relatively short-lived gold rushes. In the late and post-mining phases, mercury stored in mine tailings and river beds was transported down catchment, posing risks to ecosystems and human health over much longer time scales. These risks can be under-rated when mercury concentrations in water, sediments, and aquatic species are low enough to meet relevant guideline thresholds. In this study in Southeast Sulawesi, Indonesia, we have investigated the Costraca barnacle, Octolasmis, as a bioindicator of mercury contamination. The presence of Octolasmis parasites in mud crabs, Scylla spp., and the accumulation of mercury (Hg) in the hosts, parasites, and the ambient environment, were analyzed across both dry and wet seasons. Severe infestation of Octolasmis was assessed using prevalence, abundance, and intensity. Hg concentrations were significantly higher in the Octolasmis parasites than in the host tissues, water and sediments. The mean bioconcentration factor (BCF) of Hg equaled 7938.21 from water to parasites, and 28.91 from the host’s gill tissue to the parasites. The results suggest that Octolasmis spp. can be used effectively as a bioindicator in coastal catchments impacted by mercury contamination, even when concentrations of mercury are low in water and river sediments. The study provides the first report of Octolasmis spp. parasitized to mud crabs as a reliable bioindicator of Hg contamination and pollution.

A Study of Mercury Pollution in Water, Sediment, and Lais (Kryptopterus) Fish in the Melawi Watershed

Mercury (Hg) is a heavy metal that is very dangerous and toxic. Melawi River, a river with a length of 471 m, passes through four districts namely Menukung, Ella Hulu, Ella Hilir, and Nanga Pinoh which are the main water transportation routes in Melawi regency. This research was aimed to determine the concentration of mercury in water, sediments and Lais (Kryptopterus) fish of mercury bioconcentration factors, and the safety level of consumption the contaminated Lais (Kryptopterus) fish. The mercury measurement using Atomic Absorption Spectroscopy (AAS) showed that the average concentration of mercury found in the water was 1.80×10 -4 ppm, sediments 1.33×10 -2 ppm, and Lais fish 0.291 ppm. Meanwhile, the average bioconcentration factor (BCF) of mercury in Lais fish was 1.677 ppm. The maximum daily consumption of Lais fish that were safe for the community consumption at the Melawi watershed was 0,026 kg /day for adults and 0.006 kg/day for the children.

Mercury bioaccumulation in stream fish from an agriculturally-dominated watershed

Bioaccumulation of mercury in freshwater fish is a complex process driven by environmental and biological factors. In this study, we assessed mercury in fish from four tributaries to the Red Deer River, Alberta, Canada, which are characterized by high surface water mercury concentrations. We used carbon (δ13C) and nitrogen (δ15N) stable isotopes to examine relationships between fish total mercury (THg) concentrations, food web dynamics and patterns in unfiltered THg and methylmercury (MeHg) concentrations. We found that THg concentrations exceeded the tissue residue quality guideline for the protection of wildlife consumers in 99.7% of fish sampled. However, while the surface water THg concentration was highest in Michichi Creek and the MeHg concentration was consistent across streams, patterns of fish THg concentrations varied depending on species. Furthermore, body size and trophic level were only correlated with THg concentrations in white sucker (Catostomus commersoni) and Prussian carp (Carrasius gibelio). The results of this study suggest that mercury poses a risk to the health of piscivorous wildlife in the Red Deer River watershed. Despite high THg concentrations in these streams, mercury bioaccumulation is not driven by environmental inorganic mercury concentrations. Additionally, commonly cited factors associated with mercury concentrations in fish, such as body size and trophic level, may not strongly influence bioaccumulation in these stream ecosystems.

Chronic Effect Analysis of Mercury Exposure on Communities Around Small Scale Gold Mining in Indonesia Using Human Biomonitoring (HBM) Method

In general, small-scale gold mining activities that are spread throughout Indonesia practicing amalgamation technique. The amalgamation process in the mining activities can result in environmental degradation due to tailing waste containing mercury that are discharged into the environment and will distributed and bioaccumulated through food chain. Mercury exposure to human can give a chronic effect. Measuring mercury concentration in biomarkers such as nail and hair is a method to indicate the mercury poisoning level. Therefore, the purpose of this study was to analyze mercury concentrations in nail and hair as chronic exposure biomarkers. Besides, we also conducted Human Biomonitoring (HBM) analysis to assess mercury intoxication in the communities. Moreover, we analyzed mercury concentrations in water, rice, fish, and food crops samples to understand their association with mercury concentrations in nail and hair through a Provisional Tolerable Weekly Intake (PTWI) analysis. This research was conducted in 4 districts in Indonesia which has a significant number of small-scale gold mining activities. The results showed that the maximum concentration of T-Hg in the nail and hair of the workers was 58.48 µg/g and 55.97 µg/g, respectively. Based on HBM analysis, in several districts, more than 60% of the workers has been intoxicated by mercury. Meanwhile, Average Daily Intake (ADI) and PTWI were significantly correlated with concentration mercury in the nail and hair. Mercury concentrations in worker’s hair was significantly correlated with working experience. We identified that the age and residence duration were the major predictor of concentration mercury in nail and hair, respectively.

Trophic structure and mercury transfer in the subarctic fish community of Great Slave Lake, Northwest Territories, Canada

In recent decades, mercury concentrations have increased in fish of Great Slave Lake (GSL), a subarctic great lake in northern Canada with important recreational, subsistence, and commercial fisheries. This study characterized habitat use and trophic position of common fish species in GSL near the City of Yellowknife (Northwest Territories, Canada), measured mercury concentrations in water and in taxa from lower trophic levels of the food web, and examined trophic and biological influences on mercury concentrations within and among fish species. Northern pike (Exos lucius) and lake whitefish (Coregonus clupeformis) fed predominantly nearshore, cisco (Coregonus artedi) and longnose sucker (Catostomus catostomus) fed predominantly offshore, and burbot (Lota lota) fed roughly equally in both habitats. Habitat-specific feeding did not influence mercury bioaccumulation in fish, in contrast with published studies of smaller lakes. Water concentrations of total mercury and methylmercury were low and showed little spatial variation among sites or depths. Zooplankton (>200 μm) had similarly low methylmercury concentrations as littoral and profundal amphipods, suggesting little habitat-variation of mercury exposure near the base of the food web. Age, size, and trophic position were significant explanatory variables for muscle total mercury concentrations within populations of fish species. Among fish species, size and trophic position explained 80% of the variation in muscle total mercury concentrations. This study generated the most comprehensive dataset to date on mercury bioaccumulation in the food web of GSL, which will serve as a baseline for future studies of this great lake.

Projecting the future of Ayapel Cienaga: A hydroecologic analysis under climate change scenarios

We developed a three-component model to evaluate the present and future hydrological behavior of Ayapel Cienaga under different scenarios of climate variability and human intervention associated with fishing and mining activities and the maintenance of levees. We calibrated the water balance with historical information on hydrological variables, water levels, stream discharges, fishing activities and gold mining records in the period 1985-2015. We use autoregressive statistical models to project climate scenarios that consider extreme variations in mean monthly rainfall, ENSO activity, temperature increases of 2°C, and levee breaks along the Cauca River. In addition, we incorporated two dynamic of systems models of bocachico fish population and mercury accumulation in the Cienaga. The simulations indicate that the Cienaga levels can be affected by extreme changes in rainfall associated with ENSO. The model estimates the fraction of water that could enter from the Cauca River due to levee breaks. Furthermore, using a fish dynamic population we could project the population and catch of bocachico. Finally, the mercury balance model due to mining in the region help to estimate mercury concentrations in water, fish and aquatic macrophytes matrices. This model offers a tool for management and decision-making in ecohydrological aspects of the Cienaga under different climate change scenarios.

Analysis of mercury and its distribution patterns in water and sediment samples from Krueng Sabee, Panga and Teunom rivers in Aceh Jaya

Analysis of mercury (Hg) in water and sediment samples from Krueng Sabee (KS), Panga (P) and Teunom (T) rivers have been carried out. Water and sediment samples were collected at three different sampling points. Concentration of mercury was determined by using Atomic Absorption Spectrophotometer (AAS). Measurement of temperature, pH and salinity of the water samples was carried out in situ method. The results of in situ measurements showed a temperature ranges of 24 to 32°C, pH of 6 - 8 and salinity of 0.1 - 0.3. Based on the analysis of samples, the concentration of mercury in water and sediment samples during March 2019 (sunny condition) were 0.3328 and 6.2330 μg/L, respectively and April 2019 (rainy condition) were 0.0560 and 0.2778 μg/L, respectively. Evaluation of the pattern of Hg distribution in water and sediment samples was conducted by the Principal Component Analysis (PCA) method. The result of PCA analysis in sediment samples showed a strong correlation between Hg concentration at the KS1 and KS2 sampling points. Meanwhile, the concentration of Hg in water samples showed a strong correlation at sampling points of T2 and T3.

Assessing the utility of sulfur isotope values for understanding mercury concentrations in water and biota from high Arctic lakes

Methylmercury (MeHg) biomagnifies through aquatic food webs resulting in elevated concentrations in fish globally. Stable carbon and nitrogen isotopes are frequently used to determine dietary sources of MeHg and to model its biomagnification. However, given the strong links between MeHg and sulfur cycling, we investigated whether sulfur isotopes (δ34S) would improve our understanding of MeHg concentrations ([MeHg]) in Arctic lacustrine food webs. Delta34S values and total mercury (THg) or MeHg were measured in water, sediments, and biota from six lakes near Resolute Bay, NU, Canada. In two lakes impacted by historical eutrophication, aqueous sulfate δ34S was ∼8‰ more positive than sedimentary δ34S, suggestive of bacterial sulfate reduction in the sediment. In addition, aqueous δ34S showed a significant positive relationship with aqueous [MeHg] across lakes. Within taxa across lakes, [THg] in Arctic char muscle and [MeHg] in their main prey, chironomids, were positively related to their δ34S values across lakes, but inconsistent relationships were found across entire food webs among lakes. Across lakes, nitrogen isotopes were better predictors of biotic [THg] and [MeHg] than δ34S within this dataset. Our results suggest some linkages between Hg and S biogeochemistry in high Arctic lakes, which is an important consideration given anticipated climate-mediated changes in nutrient cycling.

DISTRIBUTION OF MERCURY IN NATURAL AND URBAN ENVIRONMENTS OF KARELIA, NORTHWEST RUSSIA

Purpose. We studied accumulation of mercury in the main natural and urban environments of Karelia, Northwest Russia, and assessed potential sources of mercury in a human body. Methods. A total of 200 samples of soil, vegetation, water, surface water, sediments and fish were collected. An analysis of samples was carried out by cold steam atomic absorption method. Diagrams of mercury distribution in soil, birch leaves and lichens were created. Data on fish consumption by the population of Petrozavodsk and Medvezhyegorsk are studied. The concentration of mercury in fish muscles most consumed in Petrozavodsk and Medvezhyegorsk was estimated. Results. Levels of mercury accumulation in soil and vegetation in the studied settings do not exceed the standards adopted in Russia. The same was observed for mercury concentration in water and sediments. Calculation of mercury intake showed that there is a 3-fold difference in the annual intake of mercury in the human body due to differences in the structure of fish consumption in these cities. Summary. External factors do not lead to higher concentrations of mercury in the main natural and urban environments of Karelia. High concentration of mercury in biological samples of pregnant women in the Medvezhyegorsk district is due to the peculiarities of the diet of the local population - the predominance in the diet of freshwater fish (pike, perch, pike perch) caught directly in the Onega lake.

Simple synthesis and characterization of l-Cystine functionalized δ-FeOOH for highly efficient Hg(II) removal from contamined water and mining waste

l-Cystine functionalized δ-FeOOH nanoparticles (Cys-δ-FeOOH) were prepared by a cheap and straightforward method for using as an adsorbent of Hg(II) in aqueous solution. X-ray diffraction (XRD), attenuated total reflectance infrared spectroscopy (ATR-IR), and Raman spectroscopy confirmed that Cys-δ-FeOOH was successfully synthesized. Cys-δ-FeOOH with 14 nm crystal size, 34 m2 g−1 surface area, and 9 nm pore size were produced. The functionalization of the δ-FeOOH surface with cysteine decreases the point of zero charge of the iron oxyhydroxide from 8.4 in δ-FeOOH to 5.7 in Cys-δ-FeOOH, which is beneficial for the adsorption of Hg(II) near neutral pH. The maximum Hg(II) adsorption capacity of the δ-FeOOH and Cys-δ-FeOOH at pH 7 were found to be 35 mg g−1 and 217 mg g−1, respectively. The kinetics data were best fitted by a pseudo-second-order model, suggesting chemical adsorption on the surface and pores of Cys-δ-FeOOH nanoparticles. Finally, δ-FeOOH and Cys-δ-FeOOH filters were constructed for purifying mercury-contaminated water. The filters were highly efficient to treat mercury-contaminated water from a Brazilian river, reducing the concentration of mercury in water to values below the allowed limits by the current legislation.

Present and Future Mercury Concentrations in Chinese Rice: Insights From Modeling

AbstractWe construct a rice paddy biogeochemical cycle model to investigate processes governing rice mercury sources and to understand factors influencing spatiotemporal variability in Chinese rice mercury concentrations. The rice paddy model takes atmospheric mercury deposition, simulated from a global atmospheric chemistry transport model (GEOS‐Chem), and soil and irrigable surface water mercury concentrations obtained from literature and calculates rice inorganic (IHg) and methylmercury (MeHg) concentrations. We use ranges of GEOS‐Chem‐simulated future atmospheric mercury deposition—no policy and strict policy to regulate mercury emissions from Chinese coal‐fired power plants under the Minamata Convention on Mercury—to simulate future rice IHg and MeHg concentrations. Sensitivity analyses suggest that rice IHg and MeHg concentrations are more sensitive to the process of soil desorption than infiltration of recently introduced mercury (atmospheric and irrigation source). The rate of internal methylation via microbial activity has the largest modeled influence on rice MeHg concentration. We find that soil mercury, rather than atmospheric deposition, explains observed spatial variability in rice IHg and MeHg concentrations and captures locations of rice mercury hot spots (>20 ng/g; China National Standard Limit). Under our future scenarios, the Chinese median rice IHg and MeHg concentration increases by 13% and decrease by 18% under no policy and strict policy, respectively. Regions with the largest percentage decline in rice IHg and MeHg concentrations under strict policy are in central China, which have high rice mercury concentrations, rice production, and consumption. Our study suggests that addressing Chinese rice mercury contamination requires attention to contaminated soil and regulation of anthropogenic mercury emissions.

Optical Properties of Dissolved Organic Matter and Their Relation to Mercury Concentrations in Water and Biota Across a Remote Freshwater Drainage Basin.

Dissolved organic matter (DOM) includes an array of carbon-based compounds that vary in size and structure and have complex interactions with mercury (Hg) cycling in aquatic systems. While many studies have examined the relationship between dissolved organic carbon concentrations ([DOC]) and methyl Hg bioaccumulation, few studies have considered the effects of DOM composition (e.g., protein-content, aromaticity). The goal of this study was to explore the relationships between total and methyl [Hg] in water, invertebrates, and fish and optically derived measures of DOM composition from 47 lake and river sites across a boreal watershed. Results showed higher aqueous total [Hg] in systems with more aromatic DOM and higher [DOC], potentially due to enhanced transport from upstream or riparian areas. Methyl [Hg] in biota were all positively related to the amount of microbial-based DOM and, in some cases, to the proportions of labile and protein-like DOM. These results suggest that increased Hg bioaccumulation is related to the availability of labile DOM, potentially due to enhanced Hg methylation. DOM composition explained 68% and 54% more variability in [Hg] in surface waters and large-bodied fish, respectively, than [DOC] alone. These results show that optical measures of DOM characteristics are a valuable tool for understanding DOM-Hg biogeochemistry.