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The European Joint Programme HBM4EU coordinated and advanced human biomonitoring (HBM) in Europe in order to provide science-based evidence for chemical policy development and improve chemical management. Arsenic (As) was selected as a priority substance under the HBM4EU initiative for which open, policy relevant questions like the status of exposure had to be answered. Internal exposure to inorganic arsenic (iAs), measured as Toxic Relevant Arsenic (TRA) (the sum of As(III), As(V), MMA, DMA) in urine samples of teenagers differed among the sampling sites (BEA (Spain) > Riksmaten adolescents (Sweden), ESTEBAN (France) > FLEHS IV (Belgium), SLO CRP (Slovenia)) with geometric means between 3.84 and 8.47 μg/L. The ratio TRA to TRA + arsenobetaine or the ratio TRA to total arsenic varied between 0.22 and 0.49. Main exposure determinants for TRA were the consumption of rice and seafood. When all studies were combined, Pearson correlation analysis showed significant associations between all considered As species. Higher concentrations of DMA, quantitatively a major constituent of TRA, were found with increasing arsenobetaine concentrations, a marker for organic As intake, e.g. through seafood, indicating that other sources of DMA than metabolism of inorganic As exist, e.g. direct intake of DMA or via the intake of arsenosugars or -lipids. Given the lower toxicity of DMA(V) versus iAs, estimating the amount of DMA not originating from iAs, or normalizing TRA for arsenobetaine intake could be useful for estimating iAs exposure and risk. Comparing urinary TRA concentrations with formerly derived biomonitoring equivalent (BE) for non-carcinogenic effects (6.4 μg/L) clearly shows that all 95th percentile exposure values in the different studies exceeded this BE. This together with the fact that cancer risk may not be excluded even at lower iAs levels, suggests a possible health concern for the general population of Europe., (Copyright © 2023 The Authors. Published by Elsevier GmbH.. All rights reserved.)

After the exploitation of coal mines in the 19th and 20th centuries in northern France, many mining slag heaps (SH) were left without any particular management or monitoring. Currently, the influence of these SHs on the quality of surrounding wetlands is hardly known. The purpose of this work is to determine the water quality in the neighbourhood of two SHs located near the city of Douai and its influence on the distribution of aquatic invertebrates in local wetlands. Our approach involves (1) the spatial and temporal characterization of the water composition (anions, major elements, sulphide, DOC and alkalinity) and of the biological diversity (aquatic invertebrates) and (2), based on this chemical and biological screening, the establishment of relationships between water quality and biodiversity distribution through multivariate data analysis. The results clearly indicate that substantial leaching from the slag heaps occurs, given the very high concentrations of dissolved sulphates (in the range of 2 g L -1 ). While the pH remains weakly basic, indicating that the leaching water has been neutralized by the highly carbonated regional substratum, high levels of biodegradable organic matter and sulphate contents have been noticed. They sporadically cause significant drops in dissolved oxygen and the occurrence of dissolved sulphides that massively reduce biodiversity, qualitatively and quantitatively. In Summer, oxygen saturation is generally lower due to the higher rate of organic matter degradation, and the risk of anoxic episodes therefore increases. Finally, as wetlands are vulnerable environments, these preliminary results suggest that monitoring and management of these sites must be attempted quickly to avoid the degradation of those valuable habitats., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

A procedure to determine lead and zinc by anodic stripping voltammetry and copper by cathodic stripping voltammetry in natural river samples was developed and validated. Cu determination involves the adsorption of Cu complexes with 8-hydroxyquinoline (oxine) onto a hanging mercury drop electrode. All samples were studied at natural pH and following optimal conditions were found: an accumulation step at -1.3 V (all potential values in the paper are given versus the Ag/AgCl, [KCl]=3M reference electrode) during 30s for determination of Zn contents and at -0.7 V during 60s for determination of Pb contents. Concerning Cu analysis, the optimal oxine concentration was found to be 10(-5)M with a deposition potential of -1.1 V during 30s followed by an adsorption step at -0.25 V during 15s. This procedure was afterwards validated by using certified reference freshwater and performing an intercalibration exercise. Finally the method was successfully applied in the Deûle River, highly contaminated by dissolved Zn and to a lesser extent by Pb and Cu, due to past and present activities of metallurgical plants. Under these optimal conditions, metal concentrations measured by our voltammetric procedures in the Deûle River were found in the range 12.4-23.2 nM for Zn, 1.7-3.2 nM for Pb and 4.9-7.6 nM for Cu., (Copyright © 2011 Elsevier B.V. All rights reserved.)

The monitoring of dissolved zinc in the Deûle river was undertaken at three different periods of the years 2008 and 2009. Electrolabile concentrations of Zn were estimated every 2 hours for several weeks by using an ATMS (Automatic Trace metal Monitoring System) based on voltammetric measurements using a solid Ag-Hg rotating disc working electrode. Complementary measurements were carried out with DGT (Diffusive Gradient in Thin films) pistons deployed directly in the river for 24 hours. Water samples filtrated at 0.45 μm were also analysed by HR-ICP-MS to estimate the total dissolved concentrations of zinc and other trace metals. High frequency monitoring of zinc over several weeks in the Deûle river indicated that the concentration could change significantly over short time periods. Resuspension of polluted sediment and biological activities are two main factors that control the behaviour of zinc in the Deûle river. Furthermore, in May 2009, daily cycles of the electrolabile zinc fraction have been observed at relatively constant total dissolved concentration. It is assumed that this particular behaviour of zinc is based on an exchange between colloids and/or nonelectrolabile forms and free cation and inorganic complexes at a daily time scale.

The behaviour of Mn, Fe, Co, Zn, Cd, Pb and Ni has been studied during early diagenesis in three different riverine sediments (Spierre, Lys and Sheldt). For that purpose (1) pore waters were extracted from sediment cores by centrifugation under nitrogen and further analyzed for the determination of total dissolved metal concentrations and (2) DET and DGT probes have been deployed in situ for the determination of high resolution profiles of labile and total dissolved metal concentrations. Furthermore, sulfidization processes have been examined; they revealed a production of pyrite near the water-sediment interface at Helkijn and Wervik sampling sites, probably due to a partial re-oxidation of reduced sulphur species. In Spierre sediments, where Eh values are the most negative, pyrite production should be mainly due to strict anaerobic processes. Concentrations of AVS in Spierre sediments are also very high and result in low TI values and low trace metal concentrations in the pore waters. Otherwise, in Wervik sediments, the low pH values combined to a TI value close to 0 results in the highest observed dissolved trace metal levels. DOS remains low at the three sites, since it does not exceed 0.4. In Wervik and Helkijn, the limitation is probably due to low sedimentary inputs of sulphate. In Spierre, sulphate is never exhausted in the pore water, suggesting a limitation of the DOS by a lack of bio-degradable organic matter. Values of Cd, Cu and Pb DGT concentrations remain low in pore waters whatever the site, due to their strong affinity with the reduced sulphur pool. It has also been demonstrated that the labile fractions of Pb and Cd are the lowest and do not exceed 0.5, while Co and Ni are the most available metals.

High resolution profiles of Mn, Tl and Fe concentrations have been assessed in the pore waters of river Leie sediments at Warneton and Menen (at the border of Belgium and France) by DET (Diffusive Equilibrium in Thin Films) and DGT (Diffusive Gradients in Thin Films) techniques. The oxidized, solid Mn (IV), Tl (III) and Fe (III) compounds were reduced in the suboxic (+255 to -20 mV versus Standard Hydrogen Electrode (SHE)) riverine sediments and since these reduced species are much more soluble also they are released into the pore waters. The highest DET (total dissolved) concentrations of Fe (76 mg l(-1)), Mn (2 mg l(-1)) were observed at the station of Menen, while Tl maxima differed only slightly between the 3 surveys (21 to 27 microg l(-1)). The average ratios of Fe/Mn/Tl in the pore waters at the 3 sampling stations are fairly constant for both the DET and DGT samplings. However, the results indicate that compared to Fe and Tl a greater proportion of the Mn measured by DET is accumulated by DGT, reflecting the ready supply of Mn from solid phase to solution.

The techniques of DET (diffusive equilibrium in thin films) and DGT (diffusive gradients in thin films) were applied to obtain high-resolution vertical profiles of trace metals in freshwater sediments. In the framework of the EU-Interreg project Stardust (http://www.vliz.be/projects/stardust/) between France and Belgium, in which the mobility of sediment bound metals is investigated, sediment samples were collected from the Upper Scheldt River (at Helkijn, Belgium) and the Leie River (at Warneton, located at the Belgian-French border). Intra- and inter-laboratory comparisons of the gel techniques were carried out between the two laboratories involved. In general, a good agreement was observed, taking sediment heterogeneity into account. At both stations, metal pore water profiles show more or less similar tendencies although the sediment at Warneton was more anoxic than at Helkijn. A strong correlation between Fe and Co was found at Helkijn as well as at Warneton. The metal gradients at the water/sediment interface were calculated from the high resolution profiles and the conventional, low resolution profiles. Significant differences were observed.