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A gravity core (220 cm depth) was collected to investigate the geochemistry, enrichment, and pollution of trace metals in anoxic sediments from San Simon Bay, an ecosystem of high biological productivity in the northwest of Spain. A five-step sequential extraction procedure was used. The Cu, Pb, and Zn contents decreased with depth, with maximum values in the top layers. Ni and Zn were bound to pyrite fractions, while Cd and Pb were associated with the most mobile fractions. The analyzed metals were associated with the fractions bound to organic matter, mainly with the strongly bound to organic matter fraction. High Cd and Cu values were observed. The fractionation showed a high mobility for Cd (28.3–100%) and Pb (54.0–70.2%). Moreover, the pollution factor and the geoaccumulation index reflected a high contamination for Pb and a moderate contamination for Cu and Zn in the superficial layers, pointing to a possible ecotoxicological risk to organisms in San Simon Bay.
A.M. Ramírez-Pérez; M.A. Álvarez-Vázquez; E. De Uña-Álvarez; E. De Blas. Environmental Assessment of Trace Metals in San Simon Bay Sediments (NW Iberian Peninsula). Minerals 2020, 10, 826 .
AMA StyleA.M. Ramírez-Pérez, M.A. Álvarez-Vázquez, E. De Uña-Álvarez, E. De Blas. Environmental Assessment of Trace Metals in San Simon Bay Sediments (NW Iberian Peninsula). Minerals. 2020; 10 (9):826.
Chicago/Turabian StyleA.M. Ramírez-Pérez; M.A. Álvarez-Vázquez; E. De Uña-Álvarez; E. De Blas. 2020. "Environmental Assessment of Trace Metals in San Simon Bay Sediments (NW Iberian Peninsula)." Minerals 10, no. 9: 826.
Ría de Vigo show over-pyritization of Fe. Pyrite formation is limited by the exhaustion of reactive Fe in deep sediments. The presence of methane gas in the sediment increase the Fe pyritization. Download : Download high-res image (277KB)Download : Download full-size image
A.M. Ramírez-Pérez; Esther de Blas; X.L. Otero. Iron pyritization in shallow methane fields in sediments of the Ría de Vigo (NW Iberian Peninsula). Estuarine, Coastal and Shelf Science 2020, 235, 106568 .
AMA StyleA.M. Ramírez-Pérez, Esther de Blas, X.L. Otero. Iron pyritization in shallow methane fields in sediments of the Ría de Vigo (NW Iberian Peninsula). Estuarine, Coastal and Shelf Science. 2020; 235 ():106568.
Chicago/Turabian StyleA.M. Ramírez-Pérez; Esther de Blas; X.L. Otero. 2020. "Iron pyritization in shallow methane fields in sediments of the Ría de Vigo (NW Iberian Peninsula)." Estuarine, Coastal and Shelf Science 235, no. : 106568.
High sedimentation rates and high organic matter contents promote the development of anoxic conditions in the Ría de Vigo (NW Spain). In these anoxic environments, elements such as S, Fe, and Mn are involved in redox processes affecting the CH4 dynamic. In this work, speciation of S, Fe, and Mn was evaluated through a five-step sequential extraction procedure (exchangeable form and bound to carbonate, present in the reductive phase bound to Fe/Mn oxides, weakly bound to organic matter, strongly bound to organic matter, and residual fractions) in order to identify the origin of S, Fe, and Mn, distinguishing between fractions bound to organic compounds from those in the sulfide phase in these anoxic sediments. The study was conducted on samples from three gravity cores retrieved in the inner and outer zones of the ría in November 2012. S was mainly found in the fraction strongly bound to organic matter, showing that S is incorporated in the organic matter. However, the S in this fraction was associated with total organic carbon only in the inner zone (r = 0.833). More than 65% of total Fe and Mn was found in the residual fraction at all zones, being the highest in the outer zone, and showing an intense diagenesis in the ría, where precipitation of these elements as sulfides is favored by anoxic conditions. SO42− reduction, Fe and Mn reduction processes coexist in the same area within the cores.
Alexandra María Ramírez-Pérez; Esther de Blas; Soledad García-Gil. Sulfur, Iron, and Manganese Speciation in Anoxic Sediments with Methane (Ría de Vigo, NW Spain). CLEAN – Soil, Air, Water 2017, 45, 1 .
AMA StyleAlexandra María Ramírez-Pérez, Esther de Blas, Soledad García-Gil. Sulfur, Iron, and Manganese Speciation in Anoxic Sediments with Methane (Ría de Vigo, NW Spain). CLEAN – Soil, Air, Water. 2017; 45 (9):1.
Chicago/Turabian StyleAlexandra María Ramírez-Pérez; Esther de Blas; Soledad García-Gil. 2017. "Sulfur, Iron, and Manganese Speciation in Anoxic Sediments with Methane (Ría de Vigo, NW Spain)." CLEAN – Soil, Air, Water 45, no. 9: 1.
The high sedimentation rates and high organic matter contents in the sediments of the Ría de Vigo (NW Spain) promote the development of anoxic conditions, determining the dynamics of elements like Fe and conditioning his speciation and reactivity. Four gravity cores were retrieved in anoxic sediments of the Ría de Vigo in November 2012. In order to understand the behavior of Fe in these complex environments different fractions of reactive iron were analyzed. The decrease in highly reactive iron and sulfide contents with depth showed the relationship between the iron and sulfur cycle in the middle and outer zones of the ría. In the inner zone, the apparition of shallow methane gas may cause the slower decrease of the highly reactive iron contents. In zones without methane, sediment layers enriched in iron -with a reactivity higher than in other sediment samples- were observed. An increase was observed in the dithionite and total reactive iron contents from the inner to the outer zone of the ría, according to the gas depth. Furthermore, a decrease in Fe (III)-bearing minerals contents with depth was observed in the outer and middle zones, but not in the innermost area where the gas is shallow. The high organic matter and sulfide contents, mainly in the inner zone of the ría, indicate that the most of the Fe (II) is FeS. Moreover, the high contents of total reactive iron and pH values (6.86-7.98) could contribute the formation of stable minerals like pyrite along the Ría de Vigo.
A.M. Ramírez-Pérez; E. De Blas. Iron reactivity in anoxic sediments in the Ría de Vigo (NW Spain). Chemosphere 2017, 174, 8 -19.
AMA StyleA.M. Ramírez-Pérez, E. De Blas. Iron reactivity in anoxic sediments in the Ría de Vigo (NW Spain). Chemosphere. 2017; 174 ():8-19.
Chicago/Turabian StyleA.M. Ramírez-Pérez; E. De Blas. 2017. "Iron reactivity in anoxic sediments in the Ría de Vigo (NW Spain)." Chemosphere 174, no. : 8-19.
Natalia Martínez-Carreño; Soledad García-Gil; V. Cartelle; Esther de Blas; A.M. Ramírez-Pérez; Tania L. Insua. Geochemical and geological factors controlling the spatial distribution of sulfate-methane transition zone in the Ría de Vigo (NW Spain). Continental Shelf Research 2017, 140, 47 -59.
AMA StyleNatalia Martínez-Carreño, Soledad García-Gil, V. Cartelle, Esther de Blas, A.M. Ramírez-Pérez, Tania L. Insua. Geochemical and geological factors controlling the spatial distribution of sulfate-methane transition zone in the Ría de Vigo (NW Spain). Continental Shelf Research. 2017; 140 ():47-59.
Chicago/Turabian StyleNatalia Martínez-Carreño; Soledad García-Gil; V. Cartelle; Esther de Blas; A.M. Ramírez-Pérez; Tania L. Insua. 2017. "Geochemical and geological factors controlling the spatial distribution of sulfate-methane transition zone in the Ría de Vigo (NW Spain)." Continental Shelf Research 140, no. : 47-59.
The Ría de Vigo (NW Spain) has a high organic matter content and high rates of sedimentation. The microbial degradation of this organic matter has led to shallow gas accumulations of methane, currently distributed all along the ría. These peculiar characteristics favor the development of anoxic conditions that can determine the dynamics of iron and manganese. In order to study the role played by iron and manganese in the processes that take place in anoxic sediments with shallow gas, four gravity cores were retrieved in anoxic sediments of the Ría de Vigo in November 2012. Methane was present in two of them, below 90cm in the inner zone and below 200cm, in the outer zone. Pore water was collected and analyzed for vertical profiles of pH, sulfide, sulfate, iron and manganese concentrations. Sulfate concentrations decreased with depth but never reached the minimum detection limit. High sulfide concentrations were measured in all cores. The highest sulfide concentrations were found in the inner zone with methane and the lowest were in the outer zone without methane. Concentrations of iron and manganese reached maximum values in the upper layers of the sediment, decreasing with depth, except in the outer zone without gas, where iron and manganese concentration increased strongly toward the bottom of the sediment. In areas with shallow gas iron reduction, sulfate reduction and methane production processes coexist, showing that the traditional redox cascade is highly simplified and suggesting that iron may be involved in a cryptic sulfur cycle and in the oxidation of methane.
A.M. Ramírez-Pérez; E. de Blas; S. García-Gil. Redox processes in pore water of anoxic sediments with shallow gas. Science of The Total Environment 2015, 538, 317 -326.
AMA StyleA.M. Ramírez-Pérez, E. de Blas, S. García-Gil. Redox processes in pore water of anoxic sediments with shallow gas. Science of The Total Environment. 2015; 538 ():317-326.
Chicago/Turabian StyleA.M. Ramírez-Pérez; E. de Blas; S. García-Gil. 2015. "Redox processes in pore water of anoxic sediments with shallow gas." Science of The Total Environment 538, no. : 317-326.
Batch and column experiments are used to study the effects of ground mussel shell amendment on the retention of heavy metals in acidic mine soil. The soil pH increases proportionally with the mussel shell concentration employed. Mussel shell amendment increases Cu, Cd, Ni and Zn retention in mine soil when compared with unamended soil. In fact, Cu retention was 6480μmolkg(-1) (43% of the total added) when the maximum metal concentration (1570μM) was added to the unamended soil, whereas retention reached 15,039μmolkg(-1) (99.9% of the total Cu added) when soil was amended with 24gkg(-1) mussel shell; in the case of Cd, adsorption increases from 3257μmolkg(-1) (15% of the total added) for the unamended soil, to 13,200μmolkg(-1) (87% of the total added) for the shell-amended soil; Ni retention increased from 3767μmolkg(-1) (25% of the total added) corresponding to unamended soil, to 11,854μmolkg(-1) (77% of the total added) for the shell-amended soil; and finally, Zn retention increased from 4684μmolkg(-1) (31% of the total added), for unamended soil, to 14,952μmolkg(-1) (98% of the total added) for shell-amended soil. The results of the constant flow transport experiments show that the addition of the 24gkg(-1) mussel shells can retain Cu, Cd, Ni and Zn within the first few centimetres of the column length, indicating the usefulness of ground mussel shells to drastically decrease the mobility and availability of these pollutants and to facilitate soil remediation.
Alexandra Mª Ramírez-Pérez; Marcos Paradelo; Juan Carlos Nóvoa-Muñoz; Manuel Arias-Estévez; María J. Fernández-Sanjurjo; Esperanza Álvarez; Avelino Núñez-Delgado. Heavy metal retention in copper mine soil treated with mussel shells: Batch and column experiments. Journal of Hazardous Materials 2013, 248-249, 122 -130.
AMA StyleAlexandra Mª Ramírez-Pérez, Marcos Paradelo, Juan Carlos Nóvoa-Muñoz, Manuel Arias-Estévez, María J. Fernández-Sanjurjo, Esperanza Álvarez, Avelino Núñez-Delgado. Heavy metal retention in copper mine soil treated with mussel shells: Batch and column experiments. Journal of Hazardous Materials. 2013; 248-249 ():122-130.
Chicago/Turabian StyleAlexandra Mª Ramírez-Pérez; Marcos Paradelo; Juan Carlos Nóvoa-Muñoz; Manuel Arias-Estévez; María J. Fernández-Sanjurjo; Esperanza Álvarez; Avelino Núñez-Delgado. 2013. "Heavy metal retention in copper mine soil treated with mussel shells: Batch and column experiments." Journal of Hazardous Materials 248-249, no. : 122-130.