Effect of Biochar and Activated Carbon Amendments on Gaseous Mercury Emissions of Soil and Mercury Methylation Rates in Sediment

Mercury is a pervasive global contaminant with a complex biogeochemical cycle. In this biogeochemical cycle, methylmercury (MeHg+) tends to biomagnify and concentrate in fish and seafood consumed by humans. This study examines the effect of sorbent amendments on both the mercury emission from soils and the methylation rates of mercury in sediments, both of which are believed to be major contributors to the global cycle. Biochar and activated carbon were used to treat soils and sediments to explore their effects. It was found that biochar and activated carbon reduced gaseous mercury emission by 25% and 49%, respectively. Methylation rates in the treated sediment effectively decreased by 89% using biochar and by 83% using activated carbon, however this does not take into account potential adsorption of MeHg+ on the amendments or the possibility of the amendments killing the microbes responsible for methylation; therefore, methylation rates could not be said to have unequivocally decreased and may be “best-case scenario” rates. All results from treated sediments were statistically different from the untreated sediment (p-value < 0.001)

Atmospheric mercury chemistry: Detection, kinetics, and mechanism

The presence of mercury in the environment is of global concern due to its toxicity. The atmosphere is an important transient reservoir for mercury released by human activities and natural sources. The knowledge of atmospheric mercury chemistry is critical for understanding the global biogeochemical cycle. In the atmosphere, mercury primarily exists in three forms: gaseous elemental mercury (GEM), gaseous oxidized mercury (GOM), and particulate-bound mercury (PBM). Over the last decade, the existing knowledge of mercury cycle has dramatically changed: (1) There has been increasing evidence that current detection methods do not accurately quantify gaseous oxidized mercury and a technique which could do both quantitative measurements and molecular speciation of atmospheric oxidized mercury is needed. (2) The gas-phase oxidation of elemental mercury initiated by bromine radical has been proposed as the major oxidation pathway, however, the experimental confirmation for the fate of HgBr radical is limited. (3) Heterogeneous reactions of gaseous oxidized mercury on environmental surfaces are poorly understood. Accordingly, the goal of this work is (a) to develop a new mass spectrometry-based detection technique, which can be employed for both laboratory and field measurements of gaseous oxidized mercury and use this technique to investigate the (b) heterogeneous reactions of gaseous oxidized mercury with environmental surfaces; and (c) the kinetics and mechanism of gas-phase reactions of elemental mercury to form gaseous oxidized mercury. This work has broad implications, it provides a better understanding of mercury chemistry in mechanisms and kinetics, which helps to model the atmospheric mercury cycle, enhance our current knowledge concerning the biogeochemical cycling of mercury, broaden our understanding of the mercury chemistry in the atmosphere, and provide a direct detection technique of atmospheric mercury which can be applied in future field and laboratory studies

Resistante to mercury of endophytic bacteria obtained in contaminated sites.

Strategies for remediation of soils contaminated with mercury (Hg) are important and necessary. Several bacterial species interfere with biogeochemical cycle of mercury and are potential tools in bioremediation and/or phytoremediation programs. These bacteria are resistant to mercury and the main mechanism of resistance is mediated by proteins codificated by operon mer. This study aims to determine the level of resistance to mercury of endophytic bacteria and detect the presence of merA gene

An Updated Review of Atmospheric Mercury

The atmosphere is a key component of the biogeochemical cycle of mercury, acting as a reservoir, transport mechanism, and facilitator of chemical reactions. The chemical and physical behavior of atmospheric mercury determines how, when, and where emitted mercury pollution impacts ecosystems. In this review, we provide current information about what is known and what remains uncertain regarding mercury in the atmosphere. We discuss new ambient, laboratory, and theoretical information about the chemistry of mercury in various atmospheric media. We review what is known about mercury in and on solid- and liquid-phase aerosols. We present recent findings related to wet and dry deposition and spatial and temporal trends in atmospheric mercury concentrations. We also review atmospheric measurement methods that are in wide use and those that are currently under development

Pollution in the open oceans: 2009-2013

This review of pollution in the open oceans updates a report on this topic prepared by GESAMP five years previously (Reports and Studies No. 79, GESAMP, 2009). The latter report, the first from GESAMP focusing specifically on the oceans beyond the 200 m depth contour, was prepared for purposes of the Assessment of Assessments, the preparatory phase of a regular process for assessing the state of the marine environment, led jointly by the United Nations Environment Programme (UNEP) and the Intergovernmental Oceanographic Commission (UNESCO-IOC)

The Minamata Convention and the future of mercury abatement

This repository item contains a single issue of Issues in Brief, a series of policy briefs that began publishing in 2008 by the Boston University Frederick S. Pardee Center for the Study of the Longer-Range Future.Pardee Faculty Fellow Henrik Selin examines the new Minamata Convention on Mercury, a global agreement intended to “protect human health and the environment from anthropogenic emissions and releases of mercury and mercury compounds.” Selin argues that the new convention is “more legally and politically important than environmentally significant.” To achieve truly meaningful reductions in mercury releases to the environment and threats to human health, he says collaborative measures must be enacted across global, regional, national, and local scales of governance, with support from inter-governmental organizations, non-governmental organizations and industry associations

Zastupljenost i specijacija žive u jadranskom planktonu, školjkašima i ribi – pregled

This article presents an overview of available research on mercury speciation in the most studied biota of the Adriatic Sea as a specific biogeochemical subunit of the Mediterranean. We present current knowledge about mercury concentration, speciation, spatial distribution and temporal changes in plankton, bivalves and fish from the Adriatic Sea. Results from mercury speciation studies in marine organisms are used to describe the extent of mercury bioaccumulation in the Adriatic Sea. Mercury biogeochemical cycle in the Adriatic is characterised by increased mercury concentrations from the water column, through plankton, bivalves and smaller fish to predator fish species. Although the Adriatic Sea has the highest mercury concentration in the whole Mediterranean Sea, fish species at the higher trophic levels have similar mercury concentrations everywhere in the Mediterranean, indicating incomplete understanding of the transfer mechanisms of mercury from seawater to upper trophic levels. As consumption of (contaminated) food is the main route of human exposure to mercury, it is of great importance to understand the influence of mercury contamination in the Adriatic Sea.Ovaj članak predstavlja pregled dostupnih istraživanja o specijaciji žive u najproučavanijoj bioti Jadranskog mora kao posebne biogeokemijske podjedinice Mediterana. Predstavljamo postojeće znanje o koncentraciji žive, specijaciji, prostornoj raspodjeli i vremenskim promjenama u planktonu, školjkašima i ribi Jadranskog mora. Rezultati studija o specijaciji žive u morskim organizmima su korišteni za opis razdiobe bioakumulacije žive u Jadranskom moru. Biogeokemijski ciklus žive u Jadranu karakterizira povećanje koncentracije žive od vodenog stupca, preko planktona, školjkaša i manjih riba do predatorskih ribljih vrsta. Iako Jadransko more sadrži najviše koncentracije žive u cijelom Mediteranu, riblje vrste na višim trofičkim razinama imaju slične koncentracije žive posvuda u Mediteranu, ukazujući na nepotpuno razumijevanje prijenosnih mehanizama žive iz morske vode na više trofičke razine. Budući da je konzumiranje (kontaminirane) hrane glavni put ljudske izloženosti živi, od iznimne je važnosti razumijevanje utjecaja kontaminacije živom u Jadranskom moru

Global change and mercury cycling: Challenges for implementing a global mercury treaty

The Minamata Convention aims to protect human health and the environment from anthropogenic emissions and releases of mercury. In the present study, the provisions of the Minamata Convention are examined to assess their influence on global biogeochemical cycling of Hg. Although the convention's scope covers all major categories of atmospheric emissions, the degree to which it will affect future emissions trajectories remains unclear. A box model analysis shows that future global biogeochemical cycling under projected technological provisions would result mainly in avoided increases and that estimated differences in atmospheric concentrations resulting from policies would be on the order of 1% to 2% per year. Present experience suggests that scientific knowledge is not currently sufficient to attribute causes to changes of this magnitude. Enhancements to capacity to measure the effectiveness of the Minamata Convention are suggested, including both measurement and modeling.National Science Foundation (U.S.) (Atmospheric Chemistry Program Award 1053648

Mercury sources and bioavailability in lakes located in the mining district of Chibougamau, eastern Canada

The presence of Hg in the fish of the lakes from the Cu–Zn–Au mining region of Chibougamau (Canada) represents a serious source of concern for the health of local sports and subsistence fishers. This study focuses on identifying the origin of Hg present in the sediments of lakes with mine wastes stored in tailing facilities located on their shores. In addition to C/N ratios and determination of total Hg, Methyl Hg and other metals, a series of lignin biomarkers were used to contrast the history of the mining contamination with the nature and the intensity of terrigenous organic matter (TOM) inputs from the watersheds to the sampled lakes. It appears that sediments located nearest to mine tailings are as expected most enriched in total Hg and other metals (Cu, As, Al, Fe, Pb). Nevertheless, the presence of only small amounts of refractory TOM in these contaminated sediments could explain why only a very small fraction of Hg is found as Methyl Hg. In sediments with little or no impact by mining activities, a relationship was observed between logging activities in the lake watershed and increased TOM derived from inorganic gymnosperms soils horizons and increased Hg transport to the lakes. Nevertheless, it appears that the additional TOM transported to logged lakes is refractory enough not to promote high levels of Methyl Hg. The highest fractions of Methyl Hg relative to total Hg in lake sediments of the studied area were thus observed in relatively pristine environments where least degraded TOM is brought from the watersheds

Mercury deposition in southern New Hampshire, 2006–2009

The atmospheric deposition of mercury (Hg) occurs via several mechanisms including wet, dry, and occult processes. In an effort to understand the atmospheric cycling and seasonal depositional characteristics of Hg, event-based wet deposition samples and reactive gaseous Hg (RGM) measurements were collected for approximately 3 years at Thompson Farm (TF), a near-coastal rural site in Durham, NH, part of the University of New Hampshire AIRMAP Observing Network. Total aqueous mercury exhibited seasonal patterns in Hg wet deposition at TF. The lowest Hg wet deposition was measured in the winter with an average total seasonal deposition of 1.56 μg m−2compared to the summer average of 4.71 μg m−2. Inter-annual differences in total wet deposition are generally linked with precipitation volume, with the greatest deposition occurring in the wettest year. Relationships between surface level RGM and Hg wet deposition were also investigated based on continuous RGM measurements at TF from November 2006 to September 2009. No correlations were observed between RGM mixing ratios and Hg wet deposition, however the ineffective scavenging of RGM during winter precipitation events was evidenced by the less frequent depletion of RGM below the detection level. Seasonal dry deposition of reactive gaseous Hg (RGM) was estimated using an order-of-magnitude approach. RGM mixing ratios and dry deposition estimates were greatest during the winter and spring. The seasonal ratios of Hg wet deposition to RGM dry deposition vary by up to a factor of 80