Chlor-alkali industrial contamination and riverine transport of mercury: Distribution and partitioning of mercury between water, suspended matter, and bottom sediment of the Thur River, France

Total dissolved and total particulate Hg mass balances were estimated during one hydrological period (July 2001–June 2002) in the Thur River basin, which is heavily polluted by chlor-alkali industrial activity. The seasonal variations of the Hg dynamics in the aquatic environment were assessed using total Hg concentrations in bottom sediment and suspended matter, and total and reactive dissolved Hg concentrations in the water. The impact of the chlor-alkali plant (CAP) remains the largest concern for Hg contamination of this river system. Upstream from the CAP, the Hg partitioning between dissolved and particulate phases was principally controlled by the dissolved fraction due to snow melting during spring high flow, while during low flow, Hg was primarily adsorbed onto particulates. Downstream from the CAP, the Hg partitioning is controlled by the concentration of dissolved organic and inorganic ligands and by the total suspended sediment (TSS) concentrations. Nevertheless, the particulate fluxes were five times higher than the dissolved ones. Most of the total annual flux of Hg supplied by the CAP to the river is transported to the outlet of the catchment (total Hg flux: 70 lg m2 a1). Downstream from the CAP, the bottom sediment, mainly composed of coarse sediment (>63 lm) and depleted in organic matter, has a weak capacity to trap Hg in the river channel and the stock of Hg is low (4 mg m2) showing that the residence time of Hg in this river is short

Impact of mercury atmospheric deposition on soils and streams in a mountainous catchment (Vosges, France) polluted by chlor-alkali industrial activity: The important trapping role of the organic matter

Total atmospheric Hg contamination in a French mountainous catchment upstream from a chlor-alkali industrial site was assessed using Hg concentrations in the deepest soil horizon, in the stream bottom sediments, in river waters and in bryophytes. The natural background level of Hg content deriving from rock weathering was estimated to 32 ng g1 in the deepest soil layers. The soils appear to be Hg contaminated in two stages: atmospheric deposition and leaching through the soil profiles of Hg-organic matter complexes. The Hg enrichment factor (EFHgSc) which could be calculated by normalization to a conservative element like Sc, allows to estimate the major contribution (63% to 95%) of the atmospheric inputs, even in the upper part of the basin. This contribution may be attributed to diffuse regional atmospheric deposition of Hg and is mainly due to the geographic location of the chlor-alkali plant. This study shows for the first time that the mercury enrichment is proportional to the carbon content indicating that most of the atmospheric mercury deposition is trapped by the organic matter contained in the soils and in the stream sediments. The Hg stock in the soils of the upper catchment and the soil erosion contribution to the riverine Hg fluxes are estimated for the first time and allow to assess the Hg residence time. It indicates that Hg is trapped in the soils of such a polluted catchment for probably several thousand years

Total mercury concentrations in an industrialized catchment, the Thur River basin (north-eastern France): geochemical background level and contamination factors

River bottom sediments and soils were collected from the industrialized Thur River basin (north-eastern France) to assess mercury contamination. The regional geochemical background level of total mercury was evaluated to calculate mercury contamination factors (Fc) in soils and river bottom sediments. Our estimate of the mean background mercury levels in river sediments and soils, not affected by human activities, was 232 ng g1 (range: 27–406 ng g1). Sediments contaminated by the effluent from a chlor-alkali plant yielded the highest contamination factors (Fc¼1784). Contamination factors of surficial soils within 1 km of the industrial site range from 6.3 to 43.6. This contamination is attributed to diffuse atmospheric deposition from this local plant. However, even upstream from this industrial area elevated contamination factors were recorded for river bottom sediments (Fc¼3.2 to 26.4) and for one alluvial soil profile (Fc¼10). This is possibly due to past pollution resulting from waste water discharges. Mercury contamination in the different horizons of alluvial soils is not correlated with soil organic carbon content, but may be the result of occasional accidental pollution arising from the introduction of contaminated suspended particulate matter by the Thur River during periods of flooding

Heavy metal distribution in the bottom sediments along Tietê river basin.

Analysis of heavy metals in fluvial sediments has been used to better understand the potential hazards and critical toxicity of heavy metals mainly related to the anthropogenic influences of urban sewage, industrial effluents and agricultural activity. The present study analyzed the heavy metals, such as Cr,Cu,Ni,Zn and Pb in the bottom sediments along the Tietê river basin, a polluted watershed in the Southeast region of brazil.The distribution of the concentrations of heavy metals in the upper basin decreased in the following order: Zn>Cr>Pb>Ni>Cu, whereas, in the middle part of the basin (wich is under strong urban and industrial influences), high concentrations of Zn, Cu and Cr were abserved measuring 648,200 and 183 µg g-1 respectively. The sequential chemical extraction in relation to the total ocncentration was used to assess the potential bioavailability of heavy metals. In the upper part of the basin, the heavy metals extracted from the bottom sediments were mainly related to the residual fraction, whereas, in the middle part of the basin, the bioavailability of Zn,Cr and Ni was higher than 60%, and these metals was mainly related to the iron oxide phase.The high concentration of heavy metals observed in the middle basin of the Tietê river(after the metropolitan area of São Paulo)when compared with the average concentration found in the geochemical bottom,showed that,in terms of enrichment factor and geoaccumulation index,the degree of pollution by Zn is high and by Ni is high to moderate in the down stream direction

Identifying the origins of local atmospheric deposition in the steel industry basin of Luxembourg using the chemical and isotopic composition of the lichen Xanthoria parietina

Trace metal atmospheric contamination was assessed in one of the oldest European industrial sites of steel production situated in the southern part of the Grand-Duchy of Luxembourg. Using elemental ratios as well as Pb, Sr, and Nd isotopic compositions as tracers, we found preliminary results concerning the trace metal enrichment and the chemical/isotopic signatures of the most important emission sources using the lichen Xanthoria parietina sampled at 15 sites along a SW-NE transect. The concentrations of these elements decreased with increasing distance from the historical and actual steel-work areas. The combination of the different tracers (major elements, Rare Earth Element ratios, Pb, Sr and Nd isotopes) enabled us to distinguish between three principal sources: the historical steel production (old tailings corresponding to blast-furnace residues), the present steel production (industrial sites with arc electric furnace units) and the regional background (baseline) components. Other anthropogenic sources including a waste incinerator and major roads had only weak impacts on lichen chemistry and isotopic ratios. The correlation between the Sr and Nd isotope ratios indicated that the Sr–Nd isotope systems represented useful tools to trace atmospheric emissions of factories using scrap metal for steel production

Rare Earth Elements as Hydrological Tracers of Anthropogenic and Critical Zone Contributions: A Case Study at the Alzette River Basin Scale.

AbstractEnrichments in Gd and LREE/HREE fractionation have been observed for the dissolved and colloidal fractions in waters of the Alzette River during low flow conditions. They can be related to the effluents of the waste water treatment plants (Gd/Gd*: 8-380 and LaN/YbN: 0.02-0.07). Mean daily flux balance calculations at the basin scale show that during low flow conditions Gd only comes from the anthropogenic effluents. When flood events occur, the Gd anomaly progressively disappears and gives way to a chemical water signature, which is closer to that of natural REE sources in the basin (Gd/Gd*<1.4 and 0.11<LaN/YbN<1.5)

Natural and anthropogenic contributions to mercury in soils and stream sediments of the upper Thur river basin (Alsace, France)

In an area where human activities (mainly and soda industry) have been releasing Hg in the environnement, natural and anthropogenic contributions to heavy contents in soils and stream sediments could be assessed using mercury concentrations in the deepest soil horizons and in the stream bottom sediments located upstream from the industrial effluents. Hg concentrations have been measured by Cold Vapor Atomic Fluorescence Spectrometry. The regional natural background level coud be estimated to 0,079+0,005µg.g-1 from the Hg contents in the deepest soil horizons (Hg deriving from rock weathering) which appear to be proportioal to the organic matter percentage. Hg concentrations in stream sediments vary between 0,108+0 001 and 8,42+0,44µg.g-1. The mercury enrichment factor (EF(Hg)) that could be calculated show that anthropogenic contribution is not negligible, even in the upper part of the basin. The relashionship between organic matter percentage ang Hg content in the deepest soil horizon allows us to estimate by difference the enthropogenic contribution (18 to 86% of the total Hg content) in the uooer stream sediments. This contribution could probably be attributed to regional atmospheric deposition of Hg

Spatial variation of trace elements in the Tiete river bottom sediments (Sao Paulo, Brazil): enrichment factors and anthropogenic contributions

The spatial variation of some trace elements (Ni, Cr, Zn, Cu, Sc, Co, Rb, Sr, Cs, Pb, Th and U) was studied in the bottom sediments of the Tietê river in São Paulo, Brazil. The main objective was to identify the enrichment factors and possible anthropic contributions to the observed high toxicity of these chemical elements in this drainage basin, which crosses the metropolitan area of São Paulo city with about 20 millions people and receives a large load of domestic and industrial wastes. The chemical analyses were performed after the chemical extraction procedure using alkaline fusion with Lithium tetraborate. An Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES) and a Neutron Activation Analysis (NAA) were used for the analytical purposes. The enrichment factor was calculated by the relationship between the concentration of each trace element in the bottom sediment and the natural soil background in the drainage basin, weighted by the conservative Sc

Rhenium complexes bearing phosphole-pyridine chelates: simple molecules with large chiroptical properties.

International audienceThe synthesis and chiroptical properties of chiral rhenium complexes bearing mono- or di-topic phosphole ligands are described. [on SciFinder(R)

Historical exposomics: a manifesto

peer reviewedThe exposome complements information captured in the genome by covering all external influences and internal (biological) responses of a human being from conception onwards. Such a paradigm goes beyond a single scientific discipline and instead requires a truly interdisciplinary approach. The concept of “historical exposomics” could help bridge the gap between “nature” and “nurture” using both natural and social archives to capture the influence of humans on earth (the Anthropocene) in an interdisciplinary manner. The LuxTIME project served as a test bed for an interdisciplinary exploration of the historical exposome, focusing on the Belval area located in the Minett region in southern Luxembourg. This area evolved from a source of mineral water to steel production through to the current campus for research and development. This article explores the various possibilities of natural and social archives that were considered in creating the historical exposome of Belval and reflects upon possibilities and limitations of the current approaches in assessing the exposome using purely a natural science approach. Issues surrounding significance, visualization, and availability of material suitable to form natural archives are discussed in a critical manner. The “Minett Stories” are presented as a way of creating new historical narratives to support exposome research. New research perspectives on the history of the Anthropocene were opened by investigating the causal relationships between factual evidence and narrative evidence stemming from historical sources. The concept of historical exposome presented here may thus offer a useful conceptual framework for studying the Anthropocene in a truly interdisciplinary fashion