Quick and robust method for trace determination of MeHg in rice and rice products without derivatisation

Peer reviewedPostprin

Médicaments et aliments : approche ethnopharmacologique = Medicines and foods : ethnopharmacological approach

Que peut-on réellement entendre par "savoir", en quoi consiste-t-il et, partant, quelles nouvelles attitudes développer ? A partir des recherches rapportées, on peut se demander si la limite pour les substances nocives se situe au-dessous du seuil de risque, lequel est franchi à la suite d'écarts alimentaires. (Résumé d'auteur

Characterization of magmatic sulfur in the Aegean island arc by means of the δ34S values of fumarolic H2S, elemental S, and hydrothermal gypsum from Nisyros and Milos islands

A delta(34)S value of +6.3 +/- 1.5% was estimated for the rhyodacitic degassing magma present underneath the hydrothermal system of Nisyros, based on the S isotope ratios of H2S in fumarolic vapors. This value was estimated by modeling the irreversible water-rock mass transfers occurring during the generation of the hydrothermal liquid which separates these fumarolic vapors. The S isotope ratio of the rhyodacitic degassing magma of Nisyros is consistent with fractional crystallization of a parent basaltic magma with an initial delta(34)S value of +4% (+/-at least 1.5%). This positive value could be explained by mantle contamination due to by either transference of fluids derived from subducted materials or involvement of altered oceanic crust, whereas contribution of biogenic sulfides from sediments seems to be negligible or nil. This conclusion agrees with the lack of N-2 and CO2 from thermal decomposition of organic matter contained in subducted sediments, which is a characteristic of the whole Aegean arc system. Since hydrothermal S at Milos and Santorini has isotope ratios similar to those determined at Nisyros, it seems likely that common controlling processes are active throughout the Aegean island arc. (C) 2002 Elsevier, Science B.V. All rights reserved

Soil diffuse degassing and thermal energy fluxes from the southern Lakki plain, Nisyros (Greece)

Two diffuse soil CO2 flux surveys from the southern Lakki plain show that CO2 is mainly released from the hydrothermal explosion craters. The correspondence between high CO2 fluxes and elevated soil temperatures suggests that a flux of hot hydrothermal fluids ascends towards the surface. Steam mostly condenses near the surface and the heat given off is conductively transferred to the atmosphere through the soil, accompanied by a large CO2 flux. Tt was calculated, that 68 t d(-1) of hydrothermal CO2 are released through the total surveyed area of similar to1.3 km(2) Admitting that a steam flux of 2200 t d(-1) accompanies this CO2 flux, the thermal energy released through steam condensation amounts to 58 MW

Mercury alkylation in freshwater sediments from Scottish canals

Funding This research was partly funded by award of a Strategic Educational Pathways Scholarship (Malta) to RC. Acknowledgement The authors wish to thank Scottish Canals (formerly British Waterways) for providing background information on the canal systems studied and granting permission to sample, and Dr Ana Teresa Reis (University of Aveiro) for conducting the Fe and S analysis in the Union Canal Sediments.Peer reviewedPostprin

Mercury alkylation in freshwater sediments from Scottish canals

Mercury concentrations were investigated in freshwater sediment from two canals in Scotland, UK. High concentrations found in the Union Canal (353-1200 mg kg(-1)) likely originate from historical munitions manufacture, with lower levels in the Forth & Clyde Canal (0.591-9.14 mg kg(-1)). Concentrations of methylmercury (MeHg) were low - from 6.02 to 18.6 mu g kg(-1) (0.001-0.023% of total Hg) in the Union Canal and from 3.44 to 14.1 mu g kg(-1) (0.11-0.58% of total Hg) in the Forth & Clyde Canal - and there was a significant inverse relationship between total Hg concentration and %MeHg. Total Hg concentration was significantly negatively correlated with pH and positively correlated with Fe content (in the Union Canal only) but not with organic matter, S content or the proportion of clay present. The MeHg concentration was not correlated with any of the above sediment parameters. Ethylmercury was detected in the most highly contaminated sediments from the Union Canal. (C) 2017 Elsevier Ltd. All rights reserved