Dynamics of mercury speciation and selenium levels in hair under seasonal and dietary influences in an Amazonian riverside population.

The Brazilian Amazon faces seasonal cycles of rising water levels and droughts, which alter dietary patterns and Hg dynamics, impacting Hg exposure and Se intake in riverine populations. This study provides a detailed assessment of total Hg and its species, as well as Se levels, in hair of riverine populations across these two distinct seasons. Mean hair Hg levels remained stable between dry (6.

Exploring mercury and selenium dynamics in Amazonian human populations: Insights from urine, blood, and plasma analyses.

The Amazonian riverside population is one of the most impacted by mercury, interestingly, with distinct selenium values in blood, generally among the highest worldwide. The interaction between Hg and Se remains to be thoroughly investigated and could provide insights into the fate of these elements and the potential for selenium-mediated detoxification. The current study explores the levels of both elements, determined by inductively coupled plasma mass spectrometry (ICP-MS), in blood, plasma, and urine, of 1089 adult individuals from communities of Tapajós and Amazon River.

Blood levels of 21 metals and metalloids in riverside villagers of the Brazilian Amazon: A human biomonitoring study with associations with sociodemographic, dietary, and lifestyle factors.

Human biomonitoring of toxic and essential trace elements is critically important for public health protection. Amazonian riverine communities exhibit distinctive dietary patterns, heavily reliant on locally sourced fish, fruits, and vegetables. These habits may result in unique exposure profiles compared to urban populations.

Biogeochemical behaviour of geogenic As in a confined aquifer of the Sologne region, France.

Arsenic (As) is one of the main toxic elements of geogenic origin that impact groundwater quality and human health worldwide. In some groundwater wells of the Sologne region (Val de Loire, France), drilled in a confined aquifer, As concentrations exceed the European drinking water standard (10 μg L). The monitoring of one of these drinking water wells showed As concentrations in the range 20-25 μg L.

Iodine distribution and volatilization in contrasting forms of forest humus during a laboratory incubation experiment.

Radionuclides I (t = 15.7 × 10 years) and I (t = 8.02 days) are both introduced into the environment as a result of nuclear human activities.

First Time Identification of Selenoneine in Seabirds and Its Potential Role in Mercury Detoxification.

Birds are principally exposed to selenium (Se) through their diet. In long-lived and top predator seabirds, such as the giant petrel, extremely high concentrations of Se are found. Selenium speciation in biota has aroused great interest in recent years; however, there is a lack of information about the chemical form of Se in (sea)birds.

Selenium distribution and speciation in waters of pristine alpine lakes from central-western Pyrenees (France-Spain).

The speciation of both redox reactive and volatile selenium (Se) compounds, barely reported in pristine aquatic environments, has never been investigated in remote alpine lakes, considered as sensitive ecosystems to detect the effect of global change. This work presents an integrated investigation on Se distribution and speciation conducted in 20 high altitude pristine lakes from the central-western Pyrenees. Five seasonal sampling campaigns were carried out after snowmelt (June/July) and in early fall (October) for the period 2017-2019.

Selenium distribution in French forests: Influence of environmental conditions.

Selenium is a trace element and an essential nutrient. Its long-lived radioisotope, selenium 79 is of potential radio-ecological concern in surface environment of deep geological repository for high-level radioactive waste. In this study, the influence of environmental, climatic and geochemical conditions on stable Se (as a surrogate of Se) accumulation was statistically assessed (PCA analysis, Kruskall-Wallis and Spearman tests) based on the analysis of its concentration in litterfall, humus, and soil samples collected at 51 forest sites located in France.

Tissue localization of selenium of parental or dietary origin in rainbow trout (Oncorhynchus mykiss) fry using LA-ICP MS bioimaging.

In relation to the decrease of selenium (Se) content in aquafeeds, the impact of level and form of parental and dietary Se supplementation was investigated in rainbow trout fry using laser ablation-inductively coupled plasma mass spectrometry (LA-ICP MS) bioimaging. The offspring of rainbow trout broodstock, fed either a control diet without any Se supplementation (0.3 mg Se/kg diet) or a diet supplemented with Se (0.

Atmospheric iodine, selenium and caesium depositions in France: I. Spatial and seasonal variations.

The spatial distribution and seasonal variations of atmospheric iodine (I), selenium (Se) and caesium (Cs) depositions remain unclear and this precludes adequate inputs for biogeochemical models. We quantified total concentrations and fluxes of these elements in rainfalls from 27 monitoring sites in France with contrasted climatic conditions; monthly measurements were taken over one year (starting in 2016/09). Since speciation of I and Se can impact their behaviour in the environment, analysis of their inorganic compounds was also conducted.

Atmospheric iodine, selenium and caesium depositions in France: II. Influence of forest canopies.

Estimation of the canopy influence on atmospheric inputs of iodine (I), selenium (Se) and caesium (Cs) in terrestrial ecosystems is an essential condition for appropriate biogeochemical models. However, the processes involved in rain composition modifications after its passage through forest canopy have been barely studied for these elements. We monitored I, Se and Cs concentrations in both rainfall and throughfall of fourteen French forested sites throughout one year, and estimated dry deposition and canopy exchange fluxes for these elements, as well as speciation of I and Se.

Dissolved Organic Matter Controls Seasonal and Spatial Selenium Concentration Variability in Thaw Lakes across a Permafrost Gradient.

Little is known about the sources and processing of selenium, an important toxicant and essential micronutrient, within boreal and sub-arctic environments. Upon climate warming and permafrost thaw, the behavior of Se in northern peatlands becomes an issue of major concern, because a sizable amount of Se can be emitted to the atmosphere from thawing soils and inland water surfaces and exported to downstream waters, thus impacting the Arctic biota. Working toward providing a first-order assessment of spatial and temporal variation of Se concentration in thermokarst waters of the largest frozen peatland in the world, we sampled thaw lakes and rivers across a 750-km latitudinal profile.

Deproteinization assessment using isotopically enriched compounds to trace the coprecipitation of low-molecular-weight selenium species with proteins.

Studies have shown that information related to the presence of low-molecular-weight metabolites is frequently lost after deproteinization of complex matrices, such as blood and plasma, during sample preparation. Therefore, the effect of several deproteinization reagents on low-molecular-weight selenium species has been compared by species-specific isotope labeling. Two isotopically enriched selenium tracers were used to mimic models of small inorganic anionic (Se-selenite) and organic zwitterionic (Se-selenomethionine) species.

Influence of Se concentrations and species in hydroponic cultures on Se uptake, translocation and assimilation in non-accumulator ryegrass.

The success of biofortification and phytoremediation practices, addressing Se deficiency and Se pollution issues, hinges crucially on the fate of selenium in the plant media in response to uptake, translocation and assimilation processes. We investigate the fate of selenium in root and shoot compartments after 3 and 6 weeks of experiment using a total of 128 plants grown in hydroponic solution supplied with 0.2, 2, 5, 20 and 100 mg L of selenium in the form of selenite, selenate and a mixture of both species.

Field study of time-dependent selenium partitioning in soils using isotopically enriched stable selenite tracer.

A better understanding of selenium fate in soils at both short and long time scales is mandatory to consolidate risk assessment models relevant for managing both contamination and soil fertilization issues. The purpose of this study was thus to investigate Se retention processes and their kinetics by monitoring time-dependent distribution/speciation changes of both ambient and freshly added Se, in the form of stable enriched selenite-77, over a 2-years field experiment. This study clearly illustrates the complex reactivity of selenium in soil considering three methodologically defined fractions (i.

Determination of the distribution and speciation of selenium in an argillaceous sample using chemical extractions and post-extractions analyses: application to the hydrogeological experimental site of Poitiers.

To better understand selenium's dynamics in environmental systems, the present study aims to investigate selenium speciation and distribution in black argillaceous sediments, partially fulfilling karstic cavities into the Hydrogeological Experimental Site of Poitiers. These sediments are suspected to be responsible for selenium concentrations exceeding the European Framework Directive's drinking water limit value (10 μg L(-1)) in some specific wells. A combination of a sequential extractions scheme and single parallel extractions was thus applied on a representative argillaceous sample.

Organotin persistence in contaminated marine sediments and porewaters: In situ degradation study using species-specific stable isotopic tracers.

This paper provides a comprehensive study of the persistence of butyltins and phenyltins in contaminated marine sediments and presents the first data on their degradation potentials in porewaters. The study's aim was to explain the different degradation efficiencies of organotin compounds (OTC) in contaminated sediments. The transformation processes of OTC in sediments and porewaters were investigated in a field experiment using species-specific, isotopically enriched organotin tracers.

Stable isotope tracing: a powerful tool for selenium speciation and metabolic studies in non-hyperaccumulator plants (ryegrass Lolium perenne L.).

Selenium is both essential and toxic for mammals; the range between the two roles is narrow and not only dose-dependent but also related to the chemical species present in foodstuff. Unraveling the metabolism of Se in plants as a function of Se source may thus lead to ways to increase efficiency of fertilization procedures in selenium deficient regions. In this study, stable-isotope tracing was applied for the first time in plants to simultaneously monitor the bio-incorporation of two inorganic Se species commonly used as foodstuff enrichment sources.