High Mercury Concentrations Research Articles

Mercury in the sea water of the Amur Bay (the Sea of Japan): Recent content and geochemical processes

Determined is the recent content of mercury in the sea water of the Amur Bay and in the local test area on Popov Island. The speciation of mercury is computed and its geochemical behavior in the marine environment is considered. The computed mercury concentration corresponds to the recent global values. High mercury content was found in the natural water layer close to natural and anthropogenic sources. Natural sources are the outcrops of deep fault structures represented by mylonitization zones.

Quantitative analysis of human remains from 18th–19th centuries using X-ray fluorescence techniques: The mysterious high content of mercury in hair

In this work, we report the unusual concentration of mercury in the hair of an individual buried in the 18th to mid-19th centuries and the comparison with the elemental composition of other remains from the same individual. Two energy dispersive X-ray fluorescence (EDXRF) setups, one with tri-axial geometry and the second one with micro-beam capabilities and a vacuum system, for light elements detection, have been used. Quantitative evaluation of the obtained spectra were made by fundamental parameters and winAXIL program by compare mode method. The levels of Hg in the hair of buried samples presented a concentration over 5% (w/w), a significantly lower presence of this element in the cranium, and no Hg in the remaining organs. Furthermore, there was no evidence of Hg in the burial soil, which has been also analyzed. From this result, we could conclude that the possibility of post-mortem contamination from the burial surroundings is very unlikely. The obtained results are indicative of the apparent use of a mercury-based compound for medical purposes, most likely lice infestation.

Levels and potential health risks of mercury in prescription, non-prescription medicines and dietary supplements in Poland

Determination of mercury is important in the case of pharmaceuticals for which the European Union regulations have not defined the maximum permissible concentration of this metal. The aim of the study was to determine the levels of mercury in the following groups of drugs (n = 119): analgesics, diuretics, cardiacs, antihypertensives, anti-influenza, antibiotics, anti-allergics, tranquilizers, antibacterials and in dietary supplements (n = 33) available on the Polish market. Mercury was analyzed using cold vapor atomic fluorescence spectrometry CV-AFS. Its content in the samples varied in the range of 0.9–476.1 ng g−1. Higher mercury concentrations were reported for prescription drugs (Rx): 0.9–476.1 ng g−1 (median: 7.4 ng g−1), lower – for non-prescription medicines (OTC): 1.2–45.8 ng g−1 (median: 6.0 ng g−1). In the analyzed dietary supplements the concentrations were: 0.9–16.7 ng g−1 (median: 5.9 ng g−1). On the basis of the information contained in the leaflet accompanying the medicine, a daily dose of mercury taken into the body with an analyzed medicament was estimated and the health risk posed by using such medicines was assessed. The study indicates that it is justified to carry out measurements of mercury in pharmaceuticals due to its high, potentially harmful.

Kinetics of Adsorption in Mercury Removal Using Cassava (Manhiot esculenta) and Lemon (Citrus limonum) Wastes Modified with Citric Acid1

The high toxic concentrations of mercury in water bodies and its negative impact on the environment has resulted in the need for research on effective and low-cost methods for the treatment of industrial effluents, such as adsorption. This research compares the feasibility and viability of the adsorption abilities of cassava and lemon citric acid-modified peels. The results showed that the modified peel of cassava has a better adsorption ability compared to that of lemon. The kinetics models that best fit the experimental data were the Pseudo-second order model and the Elovich model for both modified biomasses. This means that the mechanism that controls the adsorption is a second order reaction, and also shows that the catalytic area of the adsorbent is heterogeneous; whereas the Freundlich isotherm describes better the adsorption process. In conclusion, the use of waste material is possible for Hg (II) removal. The study of chemical modifications is suggested to improve the adsorption percentages.

Hydrochemistry of Ground Waters from Urban Wells in Almadén (Central Spain): Water Quality Around the World’s Largest Mercury Mining-Metallurgical Complex

This paper presents the results of a study on mercury distribution in urban wells from the town of Almaden (central Spain), a site that not only hosted the world’s largest mercury mine but also a large roasting plant for cinnabar (HgS). The study includes data on Hg contents in the underground waters and also quality and physical-chemical parameters such as pH, conductivity, oxidation-reduction potential (ORP), dissolved oxygen, and water temperature from 27 wells and 2 monitoring drill holes. An important proportion of the wells (16 %) display Hg concentrations above the European Union Commission (EUC) and Spanish threshold (at 1 μg L−1) and only 10 % exceeded the US EPA recommendation (at 2 μg L−1). As expected, the highest concentrations of dissolved and total Hg are found in wells near to the mine. Hydrochemical water types depend on geogenic and anthropogenic factors, for example, higher mercury concentrations are linked to water-rock interactions (e.g., oxidation, leaching) in sectors where soluble mercury compounds have formed. Hg concentrations show a decrease from 2013 to 2015, a fact that may be due to the encapsulation of the main calcines waste dump or to dilution effects related to strong rainfall events previous to the sampling survey.

Comparative sensitivity of European native (Anodonta anatina) and exotic (Corbicula fluminea) bivalves to mercury

Pollution is believed to be an important factor modulating the competition between exotic invasive bivalves and their native competitors. Thus, the objective of the present study was to compare the sensitivity of the European native Anodonta anatina and the exotic invasive species Corbicula fluminea to mercury, a ubiquitous environmental contaminant of high concern. In laboratory acute bioassays, adult organisms of both species were exposed independently to mercury for 96 h (31–500 μg/L). The criteria indicative of toxicity were mortality and biomarkers of oxidative stress and damage, neurotoxicity, and energy production changes. Mercury induced mortality in A. anatina (72 h-LC10 and 72 h-LC50 of 14.0 μg/L and 49.6 μg/L, respectively) but not in C. fluminea. The ability of C. fluminea to maintaining the shell closed for considerable periods of time when exposed to high concentrations of mercury and the effective activation (up to 63 μg/L) of mechanisms against the oxidative stress caused by mercury may have contributed to its relatively low sensitivity. In the range of concentrations tested, mercury had no significant effects on the other parameters analysed in C. fluminea. Overall, the findings of the present study, suggest that in real scenarios of competition between C. fluminea and A. anatina populations, the presence of mercury may modulate the process, acting in favour of the exotic species because it is less sensitive to this environmental contaminant than the native bivalve. The results of the present study highlight the need of further investigation on the effects of mercury on the competition between exotic invasive species and their native competitors, especially the effects potentially induced by long-term exposure to low concentrations of this metal, the mechanisms involved in the tolerance to mercury-induced stress, and the potential post-exposure recovery of both exotic invasive and native bivalves. This knowledge is most important for environmental management and assessment of the risks associated with the consumption of bivalves by humans.

Mercury (II) removal by resistant bacterial isolates and mercuric (II) reductase activity in a new strain of Pseudomonas sp. B50A

This study aimed to isolate mercury resistant bacteria, determine the minimum inhibitory concentration for Hg, estimate mercury removal by selected isolates, explore the mer genes, and detect and characterize the activity of the enzyme mercuric (II) reductase produced by a new strain of Pseudomonas sp. B50A. The Hg removal capacity of the isolates was determined by incubating the isolates in Luria Bertani broth and the remaining mercury quantified by atomic absorption spectrophotometry. A PCR reaction was carried out to detect the merA gene and the mercury (II) reductase activity was determined in a spectrophotometer at 340 nm. Eight Gram-negative bacterial isolates were resistant to high mercury concentrations and capable of removing mercury, and of these, five were positive for the gene merA. The isolate Pseudomonas sp. B50A removed 86% of the mercury present in the culture medium and was chosen for further analysis of its enzyme activity. Mercuric (II) reductase activity was detected in the crude extract of this strain. This enzyme showed optimal activity at pH 8 and at temperatures between 37 °C and 45 °C. The ions NH4(+), Ba(2+), Sn(2+), Ni(2+) and Cd(2+) neither inhibited nor stimulated the enzyme activity but it decreased in the presence of the ions Ca(2+), Cu(+) and K(+). The isolate and the enzyme detected were effective in reducing Hg(II) to Hg(0), showing the potential to develop bioremediation technologies and processes to clean-up the environment and waste contaminated with mercury.

Removal of mercury (II) from the aquatic environment by phytoremediation

Phytoremediation may be an alternative to traditional methods of removing heavy metals from the aquatic environment. In order to remove mercury at a concentration of 0.3 mg/L from Hoagland medium, two species of pleustophytes were used, namely Salvinia natans and Lemna minor. Some homogeneous cultures and another one mixed in a weight ratio of 2:1 were used. The physiological condition of the plants was controlled after 7, 14 and 21 d by evaluating biomass growth, analysing the changes in the amount of total protein and assimilation dyes. At the same time, the level of the mercury content in the base and plant tissues was controlled. The increase in biomass during plant exposure to mercury was up to 190% compared to baseline. Accumulation of mercury in plant tissues to 238.34 mg/kgd.m., contributed to a significant reduction in its concentration in the medium. The bad condition of the plants led to an attempt to support phytoremediation by micro-organisms taking an active part in the transformation of mercury. For this purpose, epiphytic bacteria, accompanying S. natans, which are resistant to mercury at a concentrations of 0.3 mg/L, were isolated. Studies indicate the possibility of using the plants S. natans and L. minor to remove mercury compounds from the aquatic environment, while providing a basis to determine the principles of design and operation of Lemna ponds, especially when the process is simultaneously stimulated by those bacteria that are resistant to high concentrations of mercury.

Morphological alterations in the liver of yellow perch (Perca flavescens) from a biological mercury hotspot

Mercury (Hg) contamination is a global issue due to its anthropogenic release, long-range transport, and deposition in remote areas. In Kejimkujik National Park and National Historic Site, Nova Scotia, Canada, high concentrations of total mercury (THg) were found in tissues of yellow perch (Perca flavescens). The aim of this study was to evaluate a possible relationship between THg concentrations and the morphology of perch liver as a main site of metal storage and toxicity. Yellow perch were sampled from five lakes known to contain fish representing a wide range in Hg concentrations in fall 2013. The ultrastructure of hepatocytes and the distribution of Hg within the liver parenchyma were analyzed by transmission electron microscopy (TEM) and electron energy loss spectrometry (EELS). The relative area of macrophage aggregates (MAs) in the liver was determined using image analysis software and fluorescence microscopy. No relation between general health indicators (Fulton's condition index) and THg was observed. In line with this, TEM examination of the liver ultrastructure revealed no prominent pathologies related to THg accumulation. However, a morphological parameter that appeared to increase with muscle THg was the relative area of MAs in the liver. The hepatic lysosomes appeared to be enlarged in samples with the highest THg concentrations. Interestingly, EELS analysis revealed that the MAs and hepatic lysosomes contained Hg.

국내산 및 수입산 참돔의 중금속 함량 및 항산화 활성과 세포독성 효과 비교

본 연구에서는 국내에서 주로 소비되는 국내산 및 수입산 참돔의 일반성분과 중금속 함량을 비교 분석하였고 생리활성을 비교하기 위하여 참돔을 용매의 극성에 따라 추출하여 항산화 및 세포독성 효과에 대해 연구하였다. 수입산과 비교했을 때 국내산 참돔은 높은 함량의 수분과 낮은 함량의 조지방, 조단백질 및 회분을 나타내었다. 국내산 및 수입산 참돔의 중금속 함량을 비교한 결과 원산지에 따른 유의적 차이를 보였으며 국내산 참돔의 수은 함량은 0.08 mg/kg으로 수입산 참돔보다 높은 함량을 나타내었으나 납의 경우 원산지에 따른 유의적 차이는 보이지 않았다. 국내산 및 수입산 참돔의 A+M 및 MeOH 추출물을 인체 섬유육종세포(HT-1080)에 처리하였을 때, 세포 내 활성산소종 생성 저해효과를 살펴 본 실험 결과, 국내산 및 수입산 참돔 추출물들에 의한 활성산소종 생성 억제효과를 비교해 보면 수입산 참돔 추출물에 의한 저해효과가 높았으며 두 추출물들 중 MeOH 추출물에 의한 저해효과가 높았음을 알 수 있었다. 인체 암세포들(AGS 및 HT-29)들에 대한 세포독성 활성 결과에서 AGS 암세포의 경우 국내산 참돔 A+M 및 MeOH 추출물들에 의한 세포독성 효과가 수입산 참돔A+M 추출물들보다 높았다. HT-29 암세포에 대해서는 국내산 참돔A+M 추출물에 의한 세포독성 효과가 수입산 참돔 A+M 추출물에 의한 것보다 높았고 MeOH 추출물에 의한 세포독성 효과는 유사했다. 따라서 본 연구 결과를 기초자료로 하여 향후 참돔의 다양한 생리활성 규명이 필요하다고 사료된다. This study compared the heavy metal contents and the effects of extracts from domestic and imported red sea bream on the antioxidant activity and cytotoxicity of human cancer cell lines. The antioxidant activity was measured using the fluorescently sensitive dye, 2’-7’ dichlorofluorescein-diacetate (DCFH-DA), and antiproliferative activity against AGS human gastric adenocarcinoma and HT-29 human colon cancer cell lines, which was determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Domestic red sea bream had a higher mercury content when compared to imported red sea bream, but there was no significant difference in the lead content. Treatments with acetone/methylene chloride (A+M) and methanol (MeOH) extracts from domestic and imported red sea bream dose-dependently decreased the H₂O₂ induced ROS production, compared to the control. The cell viability showed that treatments with the A+M and MeOH extracts had cytotoxicity in the growth of AGS and HT-29 cancer cells. In the case of AGS, the extracts from the domestic red sea bream were higher in inhibiting cancer cell growth, compared to imported red sea bream. Our results demonstrate that the heavy metal contents of domestic and imported red sea bream were below the limit of the Food Code of Korea. The results of the biological activities indicate that the antioxidant activity of extracts from imported red sea bream was more effective, while the extracts from the domestic red sea bream were stronger in cytotoxic activity.

Characterization of soil fauna under the influence of mercury atmospheric deposition in Atlantic Forest, Rio de Janeiro, Brazil

The increasing levels of mercury (Hg) found in the atmosphere arising from anthropogenic sources, have been the object of great concern in the past two decades in industrialized countries. Brazil is the seventh country with the highest rate of mercury in the atmosphere. The major input of Hg to ecosystems is through atmospheric deposition (wet and dry), being transported in the atmosphere over large distances. The forest biomes are of strong importance in the atmosphere/soil cycling of elemental Hg through foliar uptake and subsequent transference to the soil through litter, playing an important role as sink of this element. Soil microarthropods are keys to understanding the soil ecosystem, and for such purpose were characterized by the soil fauna of two Units of Forest Conservation of the state of the Rio de Janeiro, inwhich one of the areas suffer quite interference from petrochemicals and industrial anthropogenic activities and other area almost exempts of these perturbations. The results showed that soil and litter of the Atlantic Forest in Brazil tend to stock high mercury concentrations, which could affect the abundance and richness of soil fauna, endangering its biodiversity and thereby the functioning of ecosystems.

Mercury flows in a zinc smelting facility in South Korea

To prepare for the international mercury convention, the characteristics of mercury emissions from a zinc smelting facility in South Korea have been reviewed and a material flow analysis (MFA) has been conducted in this research. As inputs into the mercury MFA study, zinc ores and sulfuric acid were examined, whereas wastewater sludge, effluence water, spent catalyst, and emissions from the casting and roasting processes were examined as outputs. Mercury concentrations extracted from end products like zinc ingots, cadmium ingots, and sulfuric acid were then analyzed. Our results showed that the wastewater sludge discharged from the zinc smelting process had a relatively higher concentration of mercury, indicating that the concentration of mercury was further enriched in the wastewater sludge. The wastes discharged through the zinc smelting process should be thoroughly controlled, as results of the MFA showed that approximately 89 % of the mercury contained in the original input was later found in the waste. According to this study, the higher the concentration of mercury within zinc ores at the input stage, the higher is the mercury concentration found in the wastewater sludge at the output stage.

The efficacy of scale sampling for monitoring trace element concentrations and stable isotopes in commercially harvested walleye (Sander vitreus)

Commercial and sport fishes are subject to rigorous monitoring for concentrations of elements that could pose threats to human health, with numerous advisories issued by authorities annually for those fisheries with high mercury (Hg) concentrations. In Lake Winnipeg, Manitoba, Canada, the commercial walleye fishery is valued at more than $20 million/year, but has historically been subject to Hg advisories. We used an information theoretic approach to evaluate the utility of non-destructive fish-scale sampling to predict As, Mn and Hg concentrations, as well as stable isotope values in walleye muscle by analysing paired samples. Hg concentrations in scales were significantly related to those in muscle (r2 = 0.75), but the relationships were weaker for As and Mn. The δ15N values in scales predicted δ15N in muscle reasonably well (r2 = 0.72), whereas scale δ13C and δ34S had less predictive power for estimating their respective muscle stable isotope values. For all three isotope values, sex was a marginal predictor, with parameter confidence intervals bounding zero. Analytical constraints currently limit the utility of non-destructively analysing scales for Hg, but hindcasting trophic changes using archived walleye scales may be useful in understanding shifts in nutrients and production, particularly in impacted lake systems.

Preparation and chemical characteristics of Karunguruvai Khadi used in the traditional Siddha formulation of herbo-mineral-based medicine

IntroductionKhadi is an extract that has been used in the preparation of Pooneeru (muppu) in Siddha medicine, but it has not been scientifically evaluated for modern medicinal purposes. The present study examines the preparation and chemical composition of Khadi. Materials and methodsAccording to the method of the palm leaf literature, Karunguruvai and Samba paddy grains were selected for the preparation of Khadi. After removing the husk of the paddies, the cleaned Karunguruvai and Samba rice were processed according to the methods of Swami and Ramasamy Khon. The processed Khadi of Karunguruvai and Samba were analyzed for chemical constituents and were microbiologically assessed. The chemical composition of the paddy grains was also evaluated to compare with the Khadi constituents. ResultsThe major elements of the paddy grains of Karunguruvai and Samba were calcium (CaO) and sodium (Na2O). The predominant trace elements in the Samba rice were nickel and cadmium, whereas Karunguruvai rice contained arsenic, nickel, copper, and cadmium. Samba Khadi contained the trace elements mercury, chromium, lead, copper, and cobalt, whereas Karunguruvai Khadi had a high content of mercury, vanadium, arsenic, nickel, copper, cadmium, barium, and strontium. Karunguruvai Khadi also contained silicon dioxide (SiO2), aluminum oxide (Al2O3), iron oxide (FeO), manganese oxide (MnO), calcium oxide (CaO), and sodium carbonate (Na2O). By contrast, Samba Khadi contained only ferrous oxide (FeO), calcium oxide (CaO), sulfur dioxide (SO2), and carbon dioxide (CO2), which were chemical constituents of the Samba rice. DiscussionThe composition of Karunguruvai rice was compared with Samba rice and it is identified the absence of heavy metals in Samba as well as Karunguruvai rice. Both of rice powders have more or less similar chemical compounds except phosphorous content. Karunguruvai rice possesses more CaO than Samba rice. The bacterial and fungal activities were assessed during the different stages of Khadi preparation—no activities were found in any form of the Khadi. This suggests that Khadi may have a preventive effect against fungal and bacterial infections. ConclusionThe result of the chemical analysis of Khadi extracts showed that Khadi prepared from the Karunguruvai paddy grains (rice) was the best base solvent for ion exchange in the preparation of muppu than Samba Khadi. The analysis of the composition of these two types of Karunguruvai Khadi show that it is a good solvent for the elimination of heavy metals and for the enrichment of elements in Pooneeru powder (muppu), the chuurnam of Siddha drugs. These characteristics enhance the therapeutic potential and safety of the drugs for healing chronic diseases.

Contamination features and health risk of soil heavy metals in China

China faces a big challenge of environmental deterioration amid its rapid economic development. To comprehensively identify the contamination characteristics of heavy metals in Chinese soils on a national scale, data set of the first national soil pollution survey was employed to evaluate the pollution levels using several pollution indicators (pollution index, geoaccumulation index and enrichment factor) and to quantify their exposure risks posed to human health with the risk assessment model recommended by the US Environmental Protection Agency. The results showed that, due to the drastically increased industrial operations and fast urban expansion, Chinese soils were contaminated by heavy metals in varying degrees. As a whole, the exposure risk levels of soil metals in China were tolerable or close to acceptable. Comparatively speaking, children and adult females were the relatively vulnerable populations for the non-carcinogenic and carcinogenic risks, respectively. Cadmium and mercury have been identified as the priority control metals due to their higher concentrations in soils or higher health risks posed to the public, as well as, arsenic, lead, chromium and nickel. Spatial distribution pattern analysis implied that the soil metal pollutions in southern provinces of China were relatively higher than that in other provinces, which would be related to the higher geochemical background in southwest regions and the increasing human activities in southeast areas. Meanwhile, it should be noticed that Beijing, the capital of China, also has been labeled as the priority control province for its higher mercury concentration. These results will provide basic information for the improvement of soil environment management and heavy metal pollution prevention and control in China.

Contribution of Shellfish Consumption to Lower Mercury Health Risk for Residents in Northern Jiaozhou Bay, China.

Fish and marine mammal consumption are an important pathway for human exposure to mercury. The low mercury content in shellfish poses a low mercury health risk to people who consume shellfish. The objectives of this study are to detect mercury concentrations in different species of shellfish and to calculate the mercury health risk from shellfish consumption among traditional residents near northern Jiaozhou Bay. A total of 356 shellfish samples, which comprised 7 species from 5 different places in northern Jiaozhou Bay, were collected from April to June in 2012. The average mercury content in the collected shellfish ranged from 0.024 mg·kg−1 to 0.452 mg·kg−1. A total of 44 shellfish samples (12.36%) had mercury levels exceeding the national pollution-free aquatic products limit (0.3 mg·kg−1). Generally, the viscus had the highest mercury content among all parts of the shellfish. A positive correlation between mercury content and total weight/edible part weight was found in most species of the collected shellfish. The results showed that shellfish consumption resulted in the lower risk of mercury exposure to residents based on the calculation of daily intake (DI) and target hazard quotient (THQ).

Presencia de mercurio, plomo y cobre en tejidos de Orechromis niloticus: sector de la cuenca alta del Rio Chicamocha, vereda Volcán, Paipa, Colombia

Introduction. Heavy metals are an important toxic agent associated to environmental and industrial contamination that accumulate via fish and food, and are nowadays a public health issue, given their toxicity. In the upstream Chicamocha river no studies to determine mercury, copper and lead in fish have been made, even considering the serious contamination problems in the area due to an important industrial activity. Objective. This research work aims to determine the presence and the concentrations of heavy metals in the livers, gills and muscular tissues of Oreochromis niloticus (Linnaeus, 1758), a species that was brought and now is in a sector of the upstream Chicamocha river, located at the Volcan village, in Paipa. Materials and methods. Samples provided by artisanal fishermen were analyzed. The metals were determined by means of atomic absorption spectrophotometry. 12 samples from 4 specimens were assessed. Results. The highest mercury concentration was registered in livers and gills (5 μg/g) and the lowest, in muscular tissues (0,01 μg/g); as for lead and copper, the highest concentrations were 0,51μg/g in gills and 3,2 μg/g in livers, respectively. The samples did not exceed the threshold allowed by Colombian regulations and, due to the data from other studies. Conclusion. It is necessary to make wider research works in order to make a deeper characterization of the source and the cause of this contamination with metals. An identification of the population with potential of consuming these fish and establishing their representativeness in the diet of the region´s artisanal fishermen is recommended, in order to discard possible health hazards.

Microcosm Assessment of the Effect of an Acute Mercury Contamination Event on the Structure and Activity of Sediment Bacterial Communities

Objectives: In the present study, the effect of acute mercury contamination on the structure and activity of bacterial communities in intertidal mudflats was assessed through a microcosm experiment simulating the mobilization of highly contaminated sub-surface sediments. Methods: Box-microcosms corresponding to different test conditions were constructed by mixing natural estuarine sediments with high and low concentrations of mercury in defined proportions. The effects on sediment bacteria were characterized by quantifying bacteria using fluorescent in situ hybridization (FISH) technique, assessing the community structural diversity by denaturating gradient gel electrophoresis (DGGE) and analysing descriptors of bacterial activity (extracellular enzymatic activity and leucine incorporation) at the beginning and at the end of a 7-days incubation period. Results: At the end of the experiment, total abundance of Bacteria was significantly higher in the low-Hg microcosms than in the high-Hg and blended-sediment microcosms. DGGE patterns revealed that the structure of sediment bacterial communities responded to the experimental treatment and to the incubation time. Bacterial activity was inhibited by mercury and that the levels of arylsulfatase and biomass productivity were inversely related with the Hg concentration. The proportion sulfate-reducing in relation to total prokaryotes increased at the end of the experiment, which might indicate a differential response of Bacteria and Archaea to confinement and mercury contamination. Conclusion: Mechanical disturbance of sediments historically exposed to mercury contamination, like bottom trawling or dredging, will cause the mobilization of deeper sediments highly contaminated with Hg which will impact the less contaminated surface sediments. These acute events will impact the structure and activity of bacterial communities and their contributions to the associated biogeochemical cycles, with expectable impacts at the ecosystem level.

Wandering albatrosses document latitudinal variations in the transfer of persistent organic pollutants and mercury to Southern Ocean predators.

Top marine predators are effective tools to monitor bioaccumulative contaminants in remote oceanic environments. Here, we used the wide-ranging wandering albatross Diomedea exulans to investigate potential geographical variations of contaminant transfer to predators in the Southern Ocean. Blood concentrations of 19 persistent organic pollutants and 14 trace elements were measured in a large number of individuals (N = 180) of known age, sex and breeding status from the subantarctic Crozet Islands. Wandering albatrosses were exposed to a wide range of contaminants, with notably high blood mercury concentrations. Contaminant burden was markedly influenced by latitudinal foraging habitats (inferred from blood δ(13)C values), with individuals feeding in warmer subtropical waters having lower concentrations of pesticides, but higher concentrations of mercury, than those feeding in colder subantarctic waters. Sexual differences in contaminant burden seemed to be driven by gender specialization in feeding habitats, rather than physiological characteristics, with females foraging further north than males. Other individual traits, such as adult age and reproductive status, had little effect on blood contaminant concentrations. Our study provides further evidence of the critical role of global distillation on organic contaminant exposure to Southern Ocean avian predators. In addition, we document an unexpected high transfer of mercury to predators in subtropical waters, which merits further investigation.

Mercury analysis in hair: Comparability and quality assessment within the transnational COPHES/DEMOCOPHES project

Human biomonitoring (HBM) is an effective tool for assessing actual exposure to chemicals that takes into account all routes of intake. Although hair analysis is considered to be an optimal biomarker for assessing mercury exposure, the lack of harmonization as regards sampling and analytical procedures has often limited the comparison of data at national and international level. The European-funded projects COPHES and DEMOCOPHES developed and tested a harmonized European approach to Human Biomonitoring in response to the European Environment and Health Action Plan.Herein we describe the quality assurance program (QAP) for assessing mercury levels in hair samples from more than 1800 mother–child pairs recruited in 17 European countries. To ensure the comparability of the results, standard operating procedures (SOPs) for sampling and for mercury analysis were drafted and distributed to participating laboratories. Training sessions were organized for field workers and four external quality-assessment exercises (ICI/EQUAS), followed by the corresponding web conferences, were organized between March 2011 and February 2012. ICI/EQUAS used native hair samples at two mercury concentration ranges (0.20–0.71 and 0.80–1.63) per exercise. The results revealed relative standard deviations of 7.87–13.55% and 4.04–11.31% for the low and high mercury concentration ranges, respectively. A total of 16 out of 18 participating laboratories the QAP requirements and were allowed to analyze samples from the DEMOCOPHES pilot study. Web conferences after each ICI/EQUAS revealed this to be a new and effective tool for improving analytical performance and increasing capacity building. The procedure developed and tested in COPHES/DEMOCOPHES would be optimal for application on a global scale as regards implementation of the Minamata Convention on Mercury.