Biogeochemical factors affecting the distribution, speciation, and transport of Hg species in the Deûle and Lys Rivers (Northern France)

The Deûle River is a highly polluted River by heavy metals caused by the historical discharges of ore minerals from the former ore smelter “Metaleurop.” The potential mercury (Hg) pollution in the Deûle River implicates the importance of Hg distribution study in the river. As well as to configure the different biogeochemical factors that control the distribution and the potential transport of Hg to distant places. Four different sites were studied as follows: D-A (Deûle River, a site located upstream the river), D-B (Deûle River, a site located near a Zn, Pb, Cu, and Ni smelter that closed in 2003), L-C (Lys River, a site located upstream the confluence of the Deûle River with Lys River), and L-D (downstream the rivers confluence). Different Hg analyses were performed including total mercury in sediment (HgTS), methylmercury (MeHg) in sediment, total mercury in pore water (HgTPW), total mercury in surface water (HgTD), and total suspended particulate Hg in water (HgTP). HgTS decreases downstream from the Deûle River sites with a mean value of 11 ± 0.34 mg/kg to Lys River site (L-D) with a mean value of 0.53 ± 0.02 mg/kg at the confluence. The unaffected side of the Lys River, localized before the confluence (L-C), is characterized by low HgTS of an average value of 0.042 ± 0.003 mg/kg and high % MeHg reaching 4.2 %. Whereas, the highly contaminated Deûle sites are designated by low % MeHg with an average value of 0.053 %. Low pristine environments like that found in L-C site with more favorable biogeochemical conditions of lower concentrations of HgTS, sulfides, and Corg host more active biotic methylation than that of the highly polluted Deûle sites with high concentrations of HgTS and sulfides concentrations. Methylation in D-B (the closet site to Metaleurop smelter) is an old and recent methylation activity that has contributed to MeHg accumulation in the sediments as opposed to the exclusive recent events of methylation in Lys sites. MeHg in all sites is produced in situ rather than exported from other potential sources confirmed by significant relations of % MeHg with %Corg and AVS. Hg pollution is transported from the Deûle River to the Lys River (L-C and L-D) through suspended particles leached or remobilized from the River catchment. The dominance of reducing conditions in the Deûle River attributed to higher sulfide concentration has contributed to higher HgTPW than the Lys sites. Diffusive fluxes of HgT from sediment to water column for the Deûle and Lys River sites (L-C and L-D) were estimated to be 224, 53, and 2 ng/cm2 year, respectively

Uso de fibra y concentrado proteico de soya (Glycine max) y almidón de papa (Solanum tuberosum) como ingredientes funcionales en un chorizo fresco

34 p.El chorizo Campeño es el segundo producto mejor vendido de la Planta de Cárnicos de Zamorano. Presenta problemas técnicos durante su comercialización, purga agua y pierde color, también presenta bajo rendimiento de cocción. La formulación original tiene un alto porcentaje de carne (87.34%). Se ha identificado que la reducción de carne y adición de ingredientes funcionales podría eliminar estos problemas. El objetivo de este estudio fue elaborar formulaciones de chorizo Campeño con menos carne y tres ingredientes funcionales: fibra de soya (FS), concentrado de proteína de soya (CPS) y almidón de papa (AP), con el fin de determinar las características fisicoquímicas, microbiológicas y sensoriales de estas variaciones. Se elaboraron cuatro tratamientos; la formulación original (CTRL), el primer tratamiento con reducción de carne, el segundo tratamiento con 1.75% de (FS) Superb™ y 1.75% de (CPS) Arcon® ST y el tercer tratamiento con 3.5% de (AP) Superior®. La adición de FS y CPS redujo la purga, no influyó en los parámetros microbiológicos, presentó mayor fuerza de compresión y una menor aceptación. La adición de AP aumentó la purga, no influyó en los parámetros microbiológicos y disminuyó la fuerza de compresión del chorizo. La reducción de carne y adición de los ingredientes funcionales mejoró los problemas técnicos, los chorizos presentaron un leve descenso en la aceptación sensorial en relación a la formulación original. Se recomienda continuar estudios para mejorar las características sensoriales del producto

Caractéristiques de ressources en eau des plateaux de Akkar au Nord du Liban

L'analyse chimique de 20 ressources en eau des plateaux de Akkar au Nord du Liban a été effectuée avec une recherche des éléments à l'état de trace par ICP-AES. Les résultats obtenus révèlent l'absence d'une pollution chimique, le caractère doux des eaux et la diversité chimique des sources étudiées. Confrontées avec les connaissances sur les aquifères de la région, les sources se regroupent en fonction de la formation géologique des plateaux. Néanmoins certaines sont uniques ; c'est le cas de la source de Ain Al-Jaouzé à Hrar que se caractérise par son aspect très faiblement minéralisé (conductivité 63 µ/cm), par la quasi absence des ions majeurs (Na, Ca, K, Mg) et la présence à l'état de trace des oligo-éléments (Fe, Mn, Si, Al) ; la source de Ain Al-Aarbit à Barqayel qui se distingue par son pH légèrement acide (5.6), par la faible teneur en Mg et par la présence du Ba et du Cr à l'État de trace, alors que la source de Ain El-Helzane à Jebrayel est la plus fortement minéralisée (conductivité 310 µ/cm), c'est elle qui contient le plus de Ca, K, Na, Mg, Ni, B, quant à la source de Ain El-Delbet à El-Qamouaa, elle se caractérise par sa pureté exceptionnelle et son pH légèrement basique (8.13). Cette première étude sur la caractérisation des sources en eau à Akkar pourrait servir de base à l'exploitation de certaines de ces sources

Mercury methylation and demethylation in highly contaminated sediments from the Deûle River in Northern France using species-specific enriched stable isotopes

The methylation–demethylation processes in sediments of the Deûle River were determined using well-established isotope experiments. For this purpose, species-specific isotopically enriched tracers in the form of inorganic mercury IHg (199Hg) and methylmercury MeHg (Me201Hg) were used to determine Hg dynamics in the Deûle River. Sediment cores were collected at two sampling locations chosen in the most polluted zone of the Deûle River (Northern France) in proximity of a Zn, Pb, Cu, and Ni smelter called “Metaleurop” that had closed in 2003. Site I was chosen in the vicinity of the historic smelter site and site II upstream of the Deûle River. The incubation was realized directly in the sediment cores during the 24 hour experiment under environmental conditions close to the real natural systems (the same temperature, pH, humidity, light/dark conditions, oxygen levels…). The enriched isotopes were injected by needle into different sections of the core. After incubation, the core was sliced and the concentration of Hg species was determined in each section. The highest methylation potentials were found at sediment depths away from the sediment–water-interface. At site I, the methylation potential varied between 0.02–0.9% and at site II between 0.001–0.2%. The demethylation potentials fluctuated between 0.001–60% at site I and between 4–53% at site II. In both sites, negative net methylation potentials were obtained in several sediment depths, representing a net sink for MeHg. The average net methylation potential in site I demonstrated a negative value of 1919 ng g−1 day−1. It seems that in site I the demethylation process predominates methylation. Whereas, in site II, the average net methylation potential was a positive value of 138 ng g−1 day−1, demonstrating the dominance of methylation over demethylation

Metals sediment toxicity: Chemical approach by SEM/AVS ratio. Application on Seine estuary sediments

Within the framework of environmental quality criteria for certain heavy metals in sediment, Acid Volatile Sulphides (AVS) has been proposed as the primary standardisation parameter in combination with the amount of simultaneously extracted metals (SEM) [1]. AVS, comprising essentially iron monosulphides in sediments, are available for binding divalent cationic metals through the formation of insoluble metal-sulphide complexes, thereby controlling the metal bioavailability and subsequent toxicity for benthic biocommunities. AVS is operationally defined as the amount of sulphides that can be volatilised during a cold acid extraction. The AVS-bound metals, with environmental concern (usually Cd, Cu, Ni, Pb and Zn), are extracted at the same time and are called simultaneously extracted metals (SEM). The ratio or the difference between AVS and SEM gives an indication of the potential sediment toxicity. Such problems on extraction procedure appears: for AVS hydrochloric acid 6 mol.dm$^{-3}$ is current1y used [2-3] even so for SEM use of hydrochloric acid 1 mol.dm$^{-3}$ is advised [4-5]. To investigate the influence of acid strength, sulphides and metals extractions are realized on anoxic sediments from seine estuary. SEM/AVS ratio for different acid was calculated and toxicity associated is discussed