Holger Hintelmann

Trent University · Department of Chemistry

Fish is a rich source of protein, macronutrients, and heart-friendly Omega-3 polyunsaturated fatty acids (PUFAs), Eicosapentaenoic acid (EPA), and Docosahexaenoic acid (DHA) Along with the many benefits, if there is mercury contamination, fish will no longer be safe to eat. To protect public health from mercury exposure by eating fish, the present...

Permafrost soils are critical reservoirs for mercury (Hg), with the thawing process leading to the release of this element into the environment, posing significant environmental risks. Of particular concern is the methylated form of mercury, monomethylmercury (MMHg), known for its adverse effects on Human health. Microbial communities play a pivota...

Contamination of rice by the potent neurotoxin methylmercury (MeHg) originates from microbe-mediated Hg methylation in soils. However, the high diversity of Hg methylating microorganisms in soils hinders the prediction of MeHg formation and challenges the mitigation of MeHg bioaccumulation via regulating soil microbiomes. Here we explored the roles...

Dietary exposure to methylmercury (MeHg) causes irreversible damage to human cognition and is mitigated by photolysis and microbial demethylation of MeHg. Rice (Oryza sativa L.) has been identified as a major dietary source of MeHg. However, it remains unknown what drives the process within plants for MeHg to make its way from soils to rice and the...

The determination of the mass-independent fractionation of even Hg isotopes (even-MIF, Δ200Hg) in atmospheric samples adds another intriguing feature to the Hg isotope system. Despite our lack of sufficient experimental verification and the momentary absence of a valid mechanism to explain its occurrence, even-MIF could be instrumental in understan...

The Minamata Convention recognized mercury (Hg) as a chemical of global concern. Research in the Tagus Estuary started in the late 70’s; however, knowledge on Hg contamination in this system has greatly improved in the last decade. Results showed two highly contaminated zones, whereas, in areas far from the sources, Hg and monomethylmercury (MMHg)...

Nature archives record atmospheric mercury (Hg) depositions from directly emitted Hg and re-emitted legacy Hg. Tracing the legacy versus newly deposited Hg is still, however, challenging. Here, we measured Hg isotope compositions in three dated sediment cores at different distances from the Flin Flon smelter, the largest Canadian Hg sources to the...

Mercury (Hg) is a recognized global pollutant and its impact in ecosystems can have dramatic effects. Previous studies have reported highly Hg contaminated areas in Tagus estuary, which makes of extreme importance to understand Hg biogeochemical cycle at a local scale. In saltmarshes, recent studies have suggested that the rhizosphere of halophyte...

The Arctic terrestrial environment harbors a complex mosaic of mercury (Hg) and carbon (C) reservoirs, some of which are rapidly destabilizing in response to climate warming. The sources of riverine Hg across the Mackenzie River basin (MRB) are uncertain, which leads to a poor understanding of potential future release. Measurements of dissolved and...

Deception Island is an active volcano in the Antarctica being volcanism a source of mercury. To improve the understanding of the Hg cycle in this remote ecosystem, pyroclastic gravel and water samples were collected and total (THg) and monomethylmercury (MMHg) concentrations were measured as well as the potential for Hg methylation. Gravel samples...

Global pollution of mercury (Hg) threatens ecosystem and human health. We measured total Hg (THg) and monomethylmercury (MMHg) concentrations in filter-feeding blackfly (Simulium spp.) larvae in the inflows and the outflows of six boreal lakes with no Hg point source pollution. THg in the larvae ranged from 0.03 to 0.31 mg kg−1 dw and MMHg between...

This is the Khmer translation of the summary of the Ethical Review Protocol for the Fish Consumption Guideline for Tonle Sap Lake. Translation by Translation Services Cambodia.

A fish consumption guideline is proposed for Tonle Sap Lake to provide an educational guide to help people control their exposure to mercury. In natural healthy lakes, most fish can be eaten often while others, especially large predator fish should be restricted. Large predator fish like Trey Kray (Chitala ornata) and Trey Deab (Channa micropeltes)...

The impacts of land-application of sludge contaminated with silver nanoparticles (Ag NPs) to crop yield and nutritional quality are relatively unknown. Chili (Capsicum annuum L.), lettuce (Lactuca sativa) and radish (Raphanus sativus L.) were grown for 52 – 71 days in soil amended by sludge with or without Ag NPs. Then root-exposed chili and lettuc...

Mercury (Hg) and its stable isotope composition were used to determine the sources of Hg in deep-sea sediments of the Mediterranean Sea. Surface and down-core sediment δ202Hg values varied widely between −2.30 and +0.78‰, showed consistently positive values for mass independent fractionation of odd Hg isotopes (with average values of Δ199Hg = +0.10...

Mercury pollution is a worldwide problem, and is associated with a number of natural and anthropogenic processes. The present work, conducted in Chile, a country that has traditionally depended heavily on fossil fuels for power generation, examines total mercury (THg) and monomethylmercury (MMHg) concentrations in soils across different sites expos...

The increasing use of silver-containing nanoparticles (NPs) in commercial products has led to NP accumulation in the environment and potentially in food webs. Identifying the uptake pathways of different chemical species of NPs, such as Ag2S-NP and metallic AgNPs, into plants is important to understanding their entry into food chains. In this study...

Total mercury (THg) and monomethylmercury (MMHg) concentrations as well as mercury (Hg) isotope ratios were determined in sediment cores sampled from six locations from the Canadian Arctic Archipelago (CAA). At most sites, THg concentrations showed a decreasing trend with depth, ranging from 5 to 61 ng/g, implicating possible increased Hg depositio...

The plant Halimione portulacoides, an abundant species widely distributed in temperate salt-marshes, has been previously assessed as bioindicator and biomonitor of mercury contamination in these ecosystems. The present study aims to assess uptake and distribution of total mercury (THg) and methylmercury (MMHg) within H. portulacoides, potential mer...

Microbial activity is a critical factor controlling methylmercury formation in aquatic environments. Microbial communities were isolated from sediments of two highly mercury-polluted areas of the Tagus Estuary (Barreiro and Cala do Norte) and differentiated according to their dependence on oxygen into three groups: aerobic, anaerobic, and sulphate-...

Studies of the fate and toxicity of nanoparticles, including nanosilver (AgNPs), have been primarily conducted using bench scale studies over relatively short periods of time. To better understand the fate of AgNPs in natural aquatic ecosystems over longer time scales and ecological settings, we released suspensions of AgNPs (30–50 nm, capped with...

Lake 222 Temperature and dissolved oxygen profiles. A. Temperature (°C) and B. dissolved oxygen (mg L-1) profiles of Lake 222 during the 2014 sampling. (PDF)

Example size distribution histogram of particle diameters plotted with events detected from a single sample. Data were binned by 2 nm increments and later classified as 40–60, 60–100, or >100 nm for statistical analysis. (PDF)

Mercury (Hg) released by mining activities can be dispersed in the environment, where it is subject to species transformations. Hg isotope ratios have been used to track sources in Hg contaminated areas, although it is unclear to what extent variations in [small delta]-values are attributed to distinct Hg species. Hg was mined as Hg sulphide (cinna...

Mercury (Hg) is commonly present at trace levels in coal deposits. Geological processes, particularly magmatic intrusion and hydrothermal cycling in coal-bearing strata can significantly increase Hg levels in coals. However, the effects of thermal stress, magmatic components, magmatic-hydrothermal fluids, low-temperature hydrothermal fluids on Hg e...

Hg concentrations and isotope ratios were measured to better characterize the mercury dynamics related to Hg cycling in Amazon floodplain lakes. We collected sediments, suspended particulate material (SPM), and plankton from floodplain lakes and compared then to sediments from rivers and soils of the central Amazon basin by measuring concentrations...

Mercury (Hg) is a globally-distributed pollutant, toxic to humans and animals. Emissions are particularly high in Asia, and the source of exposure for humans there may also be different from other regions, including rice as well as fish consumption, particularly in contaminated areas. Yet the threats Asian wildlife face in rice-based ecosystems are...

In the present work, the efficiency of distillation process for extracting monomethylmercury (MMHg) from soil samples was studied and optimized using an experimental design methodology. The influence of soil composition on MMHg extraction was evaluated by testing of four soil samples with different geochemical characteristics. Optimization suggeste...

Many northern Inuit communities rely on traditional food as major source of nourishment. An essential part of the traditional Arctic diet is marine mammals such as ringed seals or beluga. Being top predators, these animals are often highly contaminated with various toxins. In contrast, some tissues of marine mammals are also characterized by high a...

Mercury (Hg) may originate from both anthropogenic and natural sources. The measurement of spatial and temporal variations of Hg isotope ratios in sediments may enable source identification and tracking of environmental processes. In this study we establish the distribution of mercury concentrations and mercury isotope ratios in surface sediments o...

Mercury (Hg) dynamics was evaluated in contaminated sediments and overlying waters from Tagus estuary, in two sites with different Hg anthropogenic sources: Cala Norte (CNOR) and Barreiro (BRR). Environmental factors affecting methylmercury (MMHg) production and Hg and MMHg fluxes across sediment/water interface were reported. [THg] and [MMHg] in s...

The widespread use of silver nanoparticles (AgNPs) raises concerns both about their accumulation in crops and human exposure via crop consumption. Plants take up AgNPs through their leaves and roots, but foliar uptake has been largely ignored. To better understand AgNPs-plant interactions, we compared the uptake, phytotoxicity, and size distributio...

Neurotoxic methylmercury (MMHg) is formed from inorganic divalent mercury (Hg 2þ). However, it is poorly understood to what extent different mercury (Hg) pools contribute to existent MMHg levels. In this study, ambient concentrations of total Hg (THg) and MMHg as well as rates of methylation and demethylation were measured simultaneously in sedimen...

Neurotoxic methylmercury (MMHg) is formed from inorganic divalent mercury (Hg 2þ). However, it is poorly understood to what extent different mercury (Hg) pools contribute to existent MMHg levels. In this study, ambient concentrations of total Hg (THg) and MMHg as well as rates of methylation and demethylation were measured simultaneously in sedimen...

The Tagus Estuary is one of the most Hg-contaminated estuaries in SW Europe. Sediment cores were sampled at two low Hg-contaminated sites inside the natural park, Alcochete (ALC) and Vale Frades (VF), and analyzed for mercury and methylmercury. Concentrations of Hg and MeHg in sediments were below 1 μg g⁻¹ and 4.4 ng g⁻¹, respectively. While in sum...

Single particle ICP-MS (spICP-MS) is a useful tool for characterizing and quantifying suspensions of metallic nanoparticles, but there are currently limitations on the minimum size of nanoparticles that can be detected using this technique. In this study, we demonstrated the spICP-MS capabilities of a double focusing magnetic sector ICP-MS instrume...

The concentration and isotopic composition of mercury (Hg) were determined in glacier core samples from Canadian Arctic ice caps dating from pre-industrial to recent time (early 21st century). Mean Hg levels increased from ≤ 0.2 ng L-1 in pre-industrial time to ~0.8-1.2 ng L-1 in the modern industrial era (last ~200 years). Hg accumulated on Arctic...

Silver nanoparticles (AgNPs) are used in a large number of consumer products due to their antimicrobial and antifungal properties, and these materials may be discharged into municipal wastewater. Wastewater treatment, including advanced oxidation processes (AOPs), may modify the forms of silver in wastewater before they are discharged into surface...

The contemporary mercury (Hg) cycle in the world's oceans has been greatly affected by human activities. However, we are still lacking reliable, long-term and continuous records of Hg in seawater. Here, we report for the first time on using annually-banded Porites coral skeletons from the northern South China Sea (SCS) as an archive for recording c...

1. The Table S2 in the original paper is downloaded as 'docx' format, you have to change it to 'xls' to view this table. 2. This table shows the modeled d202Hg, D199Hg from anthropogenic sources ('by-product', and 'all emissions') from 1850-2010, with a decade resolution.

Abstract Mercury (Hg) stable isotopes provide a new tool to trace the biogeochemical cycle of Hg. An inventory of the isotopic composition of historical anthropogenic Hg emissions is important to understand sources and post-emission transformations of Hg. We build on existing global inventories of anthropogenic Hg emissions to the atmosphere to dev...

Neurotoxic methylmercury (MeHg) is formed from inorganic divalent mercury (HgII). However, it is poorly understood to what extent different geochemical Hg pools contribute to existent MeHg levels. Many procedures have been developed to measure the concentration of MeHg from different sample matrices, and the use of isotope enriched mercury species...

Silver nanoparticles (AgNPs) are currently the most commonly used nanoparticles in consumer products, yet their environmental fate in natural waters is poorly understood. In the present study, we investigated the persistence, transformations and distribution of polyvinylpyrrolidone (PVP) and citrate (CT) coated AgNPs in boreal lake mesocosms dosed...

For the first time, Hg isotope composition of seawater in the Canadian Arctic Archipelago is reported. Hg was pre-concentrated from large volumes of seawater sampling using anion exchange resins onboard the research vessel immediately after collection. Elution of Hg was performed in laboratory followed by isotope composition determination by multi-...

The isotopic composition of mercury (Hg) is increasingly used to constrain the sources and pathways of this metal in the atmosphere. Though China has the highest Hg production, consumption and emission in the world, Hg isotope ratios are rarely reported for Chinese wet deposition. In this study, we examined, for the first time outside North America...

Our understanding of the biogeochemical cycling of monomethylmercury (MMHg) in the Arctic is incomplete because atmospheric sources and sinks of MMHg are still unclear. We sampled air in the Canadian Arctic marine boundary layer to quantify, for the first time, atmospheric concentrations of methylated Hg species (both MMHg and dimethylmercury (DMHg...

There are 19 pages of supporting information including additional information on the study site, experimental protocols and analytical methods as well as six figures and three tables.

Hg concentrations in seawater are usually too low to allow direct (without pre-concentration and removal of salt matrix) measurement of its isotope ratios with multicollector-inductively coupled plasma mass spectrometry (MC-ICP-MS). Therefore, a new method for the pre-concentration of Hg from large volumes of seawater was developed. The final metho...

We investigated concentrations of monomethyl-mercury (MMHg) at the base of benthic food webs in six lakes from polar desert (biologically poor and low annual precipitation) on Cornwallis Island (Nunavut, Canada, similar to 75 degrees N latitude). Anthropogenic mercury emissions reach the Arctic by long-range atmospheric transport, and information i...

The cycling of sulfur in freshwater environments plays an important role in the cycling of metals. In this study, acid volatile sulfides were measured at nanomolar levels using a purge-and-trap preconcentration, followed by methylene blue derivatization with HPLC separation and UV–Vis detection. The limit of detection using the preconcentration ste...

A new approach for single particle ICP-MS is introduced using internal calibration with isotope dilution to determine the size of different AgNPs. External calibration becomes unnecessary, resulting in a more rapid nanoparticle characterization and more robustness towards matrix effects. The new method is highly reproducible and shows good agreemen...

While microbial communities play a key role in the geochemical cycling of nutrients and contaminants in anaerobic freshwater sediments, their structure and activity in polar desert ecosystems are still poorly understood, both across heterogeneous freshwater environments such as lakes and wetlands, and across sediment depths. To address this questio...