Trace Metal Anomalies Research Articles

Source governed trace metal anomalies in groundwater of foothill aquifer and its health effect

An integrated study of health risk assessment, pollution indices and cluster analysis has been carried out to assess the pollution and heavy metal sources in the groundwater. Certain elements analyzed exceed the prescribed limits of WHO standard. Health risk index reveals risk of toxicity through oral pathways is less, as almost all trace elements are < 1. The distribution pattern of heavy metal pollution index, heavy metal evaluation index and degree of contamination indicates the pollution is due to urban activities. Sources were determined by cluster analysis, and it resulted in three clusters.

Response of the western proto-North Atlantic margin to the early Aptian oceanic anoxic event (OAE) 1a: an example from the Cupido platform margin-Gulf of Mexico, NE Mexico

Integrated microfacies and geochemical analyses conducted on five stratigraphic sections in northeastern Mexico (ancentral western margin of the proto-North Atlantic) reveal major paleoenvironmental changes in shallow water and pelagic environments in the prelude and run-up of the early Aptian oceanic anoxic event (OAE) 1a. During the Barremian–Aptian transition, the replacement of photozoan rudist-coral by mesotrophic/eutrophic orbitolinid-miliolid communities in the Cupido platform occurred in association with increased nutrient input. Thereafter, oligotrophic, photozoan, green algal communities repopulated briefly the carbonate ramp. Microbial-dominated ecosystems and peloidal carbonates with scarce fossils flourished before and during the onset of the OAE 1a, attesting carbonate crisis and highly stressed conditions. Organic-rich sediments deposited under weak reducing conditions in some parts of the platform. Carbonate sedimentation at the end of OAE 1a was characterized by photozoan ooid-dominated facies documenting a recovery phase of marine alkalinity. The studied carbonate platform shows a response mode to OAE 1a marked by continuous carbonate production, presumably protected by the “kettle effect”, but accompanied by significant ecological perturbations and incipient drowning. The documented change shares attributes of both central/southern and northern Tethyan platforms response modes. The OAE 1a deposits in the pelagic setting are characterized by organic-rich, radiolarian-dominated carbonates accumulated under oxygen-restricted bottom water conditions and during enhanced nutrient input linked to intense chemical weathering. The intensity of the trace metal anomalies suggests that volcanic-hydrothermal activity associated with the construction phases of the Ontong Java LIP also influenced the elemental abundance in the proto-Atlantic water mass.

Integrated geo-microbial and trace metal anomalies for recognition of hydrocarbon microseepage in petroliferous regions: case of El Hajeb oilfield in the South East of Tunisia

In this work we attempt to identify the geomicrobial fingerprints alongside with trace metals anomalies, and to explore whether the geomicrobial signatures are correlated with trace metals in El Hajeb oilfield in Tunisia. 51 soil samples are collected in grid pattern of 1 × 1 km interval. After incubating soil samples with propane in mineral salt medium, we count the propane oxidizing bacteria abundance ranged from nil to 2.44 × 105 cfu/g of soil sample. It was found that the concentrations of trace elements are enormously increased when they are compared with the natural background concentrations of metals in soils.

Limnochemistry of the remote, high mountain Lake Marboré (Ordesa and Monte Perdido National Park, Central Pyrenees): Stratification dynamics and trace metal anomalies

espanolEl lago o ibon de Marbore es un lago alpino de alta montana (2612 m.s.n.m.), situado en el area central de los Pirineos (NE de Espana), que forma parte del Parque Nacional de Ordesa y Monte Perdido. Este emblematico lago de origen glacial se alimenta principalmente de nieve y aguas de fusion, y su arroyo emisario da origen al rio Cinca. Las condiciones climaticas extremas que se dan en esta zona y las dificultades para muestrear y monitorizar, debido a la gruesa capa de hielo y nieve que cubre este circo glaciar durante la mayor parte del ano, han hecho que este lago no haya sido investigado en profundidad hasta el momento. Aunque existian algunos estudios paleolimnologicos mediante sondeos, hasta ahora no se habia investigado su limnologia (incluyendo limnoquimica, dinamica de estratificacion y ecologia microbiana). Este trabajo presenta los principales descubrimientos y conclusiones de un estudio llevado a cabo en el lago durante tres campanas estivales consecutivas (2013 a 2015, siempre en septiembre). Se describe su dinamica de estratificacion y su hidroquimica (incluyendo la disponibilidad de nutrientes y la dinamica de metales pesados), asi como los parametros basicos relacionados con la actividad biologica, como el consumo de oxigeno y la quimica redox. Nuestros resultados demuestran que Marbore es un lago ultra-oligotrofico y alberga una reducida actividad biologica, tipico de lagos de alta montana. Al comienzo del periodo de deshielo se desarrolla una ligera estratificacion, con pequenos gradientes verticales de temperatura (3-11 oC) y conductividad electrica (60-100 µS/cm) entre el fondo (situado a aproximadamente 28 m de profundidad) y la superficie del lago. El pH actual (entre 7.0 y 7.8, inferior a medidas previas) no es compatible con la formacion de calcita en la columna de agua, resultado coherente con la mineralogia del registro sedimentario. El resultado geoquimico mas interesante es, sin embargo, la presencia de concentraciones significativas de metales traza disueltos (Fe y Zn) y sulfatos, junto con particulas minerales en suspension (incluidos sulfatos), cerca de la termoclina. Estas altas concentraciones sugieren que la oxidacion local de sulfuros influye sobre la quimica del lago. EnglishLake Marbore (or Ibon de Marbore) is a high-altitude (2612 m a.s.l.) alpine lake situated in the central area of the Pyrenees range (NE Spain), which forms part of Ordesa and Monte Perdido National Park. This emblematic lake of glacial origin is chiefly fed by snow and meltwater, and the outlet is the headwaters of the Cinca River. Given the extreme climatic conditions prevailing in the area and the difficulty of sampling and monitoring due to the thick layer of ice and snow that covers the cirque most of the year, this lake has been the subject of very little scientific research. Although some paleolimnological studies have been performed on sediment cores, no previous investigation has been carried out on the limnology (including limnochemistry, stratification dynamics and microbial ecology) of this lake. This work presents the main findings and conclusions that have emerged from a recent study conducted in the lake over the course of three summer campaigns (2013 to 2015, always in September). We report the stratification dynamics and water chemistry of this lake (including the nutrient availability and trace metal dynamics), as well as basic parameters related to the biological activity, such as O2 consumption and redox chemistry. Our results show that Marbore is ultra-oligotrofic and hosts very low biological activity, typical of high mountain lakes. A slight stratification developed at the beginning of the ice-free period, with small vertical gradients in temperature (3-11 oC) and electrical conductivity (60-100 µS/cm) between the bottom (situated at approximately 28 m depth) and the lake surface. The current pH (between 7.0 and 7.8, which is lower than previous measurements) is not compatible with the formation of calcite in the water column. This finding is coherent with the mineralogy of the sedimentary record. The most interesting geochemical finding, however, relates to the presence of significant concentrations of dissolved trace metals (Fe and Zn) and sulfate, along with suspended mineral particles (including sulfates), near the thermocline. These high concentrations suggest that local sulfide oxidation processes influence the lake chemistry.

Integrated Geo-Microbial and Trace Metal Anomalies for Detection of Hydrocarbon Microseepage in Ahmedabad Block of Cambay Basin, India

Abstract: The aim of the present work is to define the geo-microbial signatures along with trace metals, and to investigate whether the geo-microbial anomalies have correlation with trace metal anomalies in Ahmedabad block of Cambay basin. The surface geochemical techniques are based on seepage of light hydrocarbon gases from the oil and gas pools to the shallow surface and can bring up near-surface oxidation reduction zones that favor the development of a diverse array of chemical and mineralogical changes. The paper reports the role of hydrocarbon microseepage in surface alterations of trace metal concentrations and hydrocarbon oxidizing bacteria and its interrelationship. For the purpose a total of 90 soil samples are collected in grid pattern of 2 x 2 km interval. The paper reports the chemical alterations associated with trace metals in soils that are related to hydrocarbon microseepages above some of the major oil and gas fields of this petroliferous region. The concentrations of V (0 to149 ppm), Cr (2 to 192 ppm), Cu (4 to 171 ppm), Se (98 to 440 ppm), Zn (56 to 1215 ppm) are obtained. It is observed that the concentrations of trace elements are tremendously increased when they are compared with their normal concentrations in soils. In this study the hydrocarbon oxidizing bacterial counts ranged between 1.0 x 103 and 1.59 x 106 cfu/g of soil sample respectively. The attempt has made for the first time, which revealed good correlation as both these anomalies are found as apical in relation. Integrated studies between trace elements and hydrocarbon oxidizing bacterial anomalies showed positive correlation with existing oil and gas wells in the study area.

Trace metal anomalies in bleached Porites coral at Meiji Reef, tropical South China Sea

Coral bleaching has generally been recognized as the main reason for tropical coral reef degradation, but there are few long-term records of coral bleaching events. In this study, trace metals including chromium (Cr), copper (Cu), molybdenum (Mo), manganese (Mn), lead (Pb), tin (Sn), titanium (Ti), vanadium (V), and yttrium (Y), were analyzed in two Porites corals collected from Meiji Reef in the tropical South China Sea (SCS) to assess differences in trace metal concentrations in bleached compared with unbleached coral growth bands. Ti, V, Cr, and Mo generally showed irregular fluctuations in both corals. Bleached layers contained high concentrations of Mn, Cu, Sn, and Pb. Unbleached layers showed moderately high concentrations of Mn and Cu only. The different distribution of trace metals in Porites may be attributable to different selectivity on the basis of vital utility or toxicity. Ti, V, Cr, and Mo are discriminated against by both coral polyps and zooxanthellae, but Mn, Cu, Sn, and Pb are accumulated by zooxanthellae and only Mn and Cu are accumulated by polyps as essential elements. The marked increase in Cu, Mn, Pb, and Sn are associated with bleaching processes, including mucus secretion, tissue retraction, and zooxanthellae expulsion and occlusion. Variation in these trace elements within the coral skeleton can be used as potential tracers of short-lived bleaching events.

Geochemical evidences of trace metal anomalies for finding hydrocarbon microseepage in the petroliferous regions of the Tatipaka and Pasarlapudi areas of Krishna Godavari Basin, India

The long-term seepage of hydrocarbons, either as macroseepage or microseepage, can set up near-surface oxidation reduction zones that favor the development of a diverse array of chemical and mineralogical changes. The bacterial oxidation of light hydrocarbons can directly or indirectly bring about significant changes in the values of pH and Eh of the surrounding environment, thereby also changing the stability fields of the different mineral species present in that environment. The paper reports the role of hydrocarbon microseepage in surface alterations of trace metal concentrations. In this study trace metal alterations were mapped that appear to be associated with hydrocarbon microseepages in the oil/gas fields. A total of 50 soil samples were collected near oil and gas fields of the Tatipaka and Pasarlapudi areas of the Krishna Godavari Basin, Andhra Pradesh. The soil samples were collected from a depth of 2–2.5 m. The paper reports the chemical alterations associated with trace metals in soils that are related to hydrocarbon microseepages above some of the major oil and gas fields of this petroliferous region. Trace metals, such as scandium (Sc), vanadium (V), chromium (Cr), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), barium (Ba) and strontium (Sr), in soil samples were analyzed using inductively coupled plasma-mass spectrometry (ICP-MS). The concentrations of Sc (8 to 40 mg/kg), V (197 to 489 mg/kg), Cr (106 to 287 mg/kg), Co (31 to 52 mg/kg), Ni (65 to 110 mg/kg), Cu (88 to 131 mg/kg), Zn (88 to 471 mg/kg), Ba (263 to 3,091 mg/kg) and Sr (119 to 218 mg/kg) were obtained. It was observed that the concentrations of trace elements were tremendously increased when they were compared with their normal concentrations in soils. The analysis of adsorbed soil gas showed the presence of high concentrations of ΣC2+ (C2H6, C3H8 and n-C4H10) ranging from 7 to 222 μg/kg respectively. Integrated studies of trace elements over adsorbed light gaseous hydrocarbons (ΣC2+) anomalies showed good correlation with the existing oil and gas wells. The carbon isotopic composition of δ13C1 of the samples ranges between −36.6‰ to −22.7‰ (Pee Dee Belemnite) values indicate thermogenic origin, which presents convincing evidence that the adsorbed soil gases collected from these sediments are of catagenetic origin. The increase in the concentrations of trace metals near oil/gas producing areas, suggests a soil chemical change to a reducing environment, presumably due to the influence of hydrocarbon microseepage, which could be applied with other geoscientific data to identify areas of future hydrocarbon exploration in frontier areas.

Application of Trace Metal Anomalies for Recognition of Petroleum Prospects in Surface Sediments of Kutch and Saurashtra Basins, India

Abstract: Seepage of hydrocarbons, either as macroseepage or microseepage, can set up near-surface oxidation-reduction zones that favour the development of a diverse array of chemical and mineralogic changes. In this study trace metal alterations were mapped that appear to be associated with hydrocarbon microseepages in the oil/gas fields. A total of 210 soil samples were collected from near surface sediments of Kutch and Saurashtra Basins, India. The soil samples were collected from a depth of 2 - 2.5 m. The paper reports the chemical alterations associated with trace metals in soils that are related to hydrocarbon microseepages above the Kutch and Saurashtra Basins, India. The soil samples for trace metals; Scandium (Sc), Vanadium (V), Chromium (Cr), Cobalt (Co), Nickel (Ni), Copper (Cu), Zinc (Zn), Barium (Ba) and Strontium (Sr) were analyzed using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The concentrations of the trace elements ranged between for Sc (12.69 to 21.91 ppm), V (109.20 to 436.05 ppm), Cr (87.15 to 481.57 ppm), Co (18.25 to 64.31 ppm), Ni (57.55 to 263.15 ppm), Cu (44.88 to 143.96 ppm), Zn (137.60 to 502.31 ppm), Ba (149.27 to 921.46 ppm) and Sr (143.93 to 425.63 ppm) were obtained. It was observed that trace elements concentrations were tremendously increased when compared with normal concentration in the soils. The adsorbed soil gas analysis showed the presence of high concentrations of ∑C2+ (C2H6, C3H8 and n-C4H10) ranged between 1 to 121 ppb respectively. Integrated studies of trace elements over adsorbed light gaseous hydrocarbon (∑C2+) anomalies showed good correlation. The carbon isotopic composition of δ13C1 of the samples ranges between – 36.6 ‰ to -22.7‰ (Pee Dee Belemnite) suggest thermogenic source for hydrocarbon gases. The increase in trace metal concentrations near oil/gas producing areas, suggests that soil chemical change to a reducing environment, presumably due to the influence of hydrocarbon microseepage, which could be applied with other geo-scientific data to identify areas of future hydrocarbon exploration in the frontier areas.

Evidence for a relationship between hydrocarbon microseepage and trace metal anomalies: an implication for petroleum exploration

The paper reports the role of hydrocarbon microseepage in surface alterations of trace metal concentrations. In this study trace metal alterations were mapped that appear to be associated with hydrocarbon microseepages in the oil/gas fields of Mehsana block, North Cambay basin, India. The ranges of adsorbed soil gas concentrations of Methane, Ethane, Propane, i-Butane and n-Butane are found to vary from 1–402 ppb, 1–135 ppb, 1–70 ppb, 1–9 ppb, 1–18 ppb respectively, suggesting the presence of hydrocarbons and microseepage associated with the study area. The carbon isotopic signature of methane ranged from −29.5 to −43.0‰ (PDB) and ethane from −19.1 to −20.9‰ (PDB), indicating a thermogenic source of hydrocarbons. The absence of any significant correlation of Total Organic Carbon (TOC) and Total Inorganic Carbon (TIC) (r = 0.1 and 0.5 respectively) content with hydrocarbons in soil samples demonstrates the catagenetic origin of the desorbed gases. The Trace metal concentrations varied in the following manner: Ni: 49–155 ppm, V: 67–158 ppm, Cu: 29–82 ppm, Zn: 64–327 ppm, Ba: 241–554 ppm and Sr: 118–892 ppm. These high concentrations of trace metals which are more than their respective average concentrations generally found in soils are indicative of hydrocarbon induced alterations in the area. The low Eh values observed in anomalous hydrocarbon bearing soil samples compared to non anomalous samples in the area, could be attributed to the reducing conditions created by the hydrocarbon seepage from subsurface and might have influenced the trace metal solubilities which is reflected in their increased concentrations. Trace metal anomalies are seen haloed to adsorbed soil gas anomalies (ΣC2+) indicating that the major generative depressions of oil and /or gas fields of Sobhasan / Linch in the study area promoted vertical migration of hydrocarbon microbubbles which in turn facilitated trace metal deposition in the surface soils. By using integrated method approach, the weak signal of oil and gas reservoirs could be amplified in the frontier areas and the uncertainity of the vertical correlation of surface anomalies could be reduced.

Hydrothermal fluid emanations from the submarine Kick'em Jenny volcano, Lesser Antilles island arc

Little is known about the role of island arcs as hydrothermal sources to the ocean when compared to the extensive research that has been carried out on hydrothermal systems at spreading ridges, although increasingly more work is being done on intraoceanic arcs. Here, we present fluid geochemistry data from the Kick'em Jenny (KeJ) submarine volcano of the Lesser Antilles island arc. Discharge of diffuse hydrothermal fluid was discovered on the southwestern flanks of the volcano. Hydrothermal input into the water column was recognized from CH 4 and trace-metal anomalies in water-column profiles in a depth range of 500–700 m. Samples collected directly on the seafloor also showed evidence for hydrothermal emissions where Mg and Cl were depleted in the fluids compared to ambient seawater, while CH 4 and several trace metals were enriched. The chemical composition of these samples, including O and H isotope data, suggests that the fluids are a mixture between a condensed vapor phase derived from a phase-separated hydrothermal fluid, which was conductively cooled in the sub-surface, and seawater. Increased dissolved organic carbon (DOC) concentrations of the fluids also indicate interaction with the sediment layer through which the fluids percolated. Although the volcanic crater could not be sampled directly due to safety concerns, δ 3He and some trace-metal values in seawater samples indicate fluid input containing a mantle component, probably from a hot, focused-flow source in the crater region around 200–300 m depth.

Trace element abundances in the Rock Canyon Anticline, Pueblo, Colorado, marine sedimentary section and their relationship to Caribbean plateau construction and oxygen anoxic event 2

Rapid eruption of submarine lava flows during formation of the Caribbean plateau correlates closely with ocean anoxic event 2 (OAE2), which bracketed the Cenomanian/Turonian boundary (∼93.5 Ma). These events also correspond with a positive excursion in carbon isotopic composition of seawater. Hydrothermal activity associated with large‐scale submarine volcanism may have been responsible for this abrupt change in ocean chemistry. We determined the distribution of major, minor, and trace element abundances in the Rock Canyon marine sedimentary section (Pueblo, Colorado). After normalizing element concentrations to Zr to remove the variable contribution of terrigenous material to these sediments, we detected an interval of concentrated metal abundance anomalies that coincides with the abrupt beginning of the positive δ13C isotope excursion. The metal abundance anomalies indicate that intermittent hydrothermal activity, in the form of both water/rock exchange and magmatic degassing, introduced large concentrations of trace metals into the Cretaceous ocean at the same time that extinctions of benthic species, turnover in plankton communities, and increases in isotopically light organic carbon burial occurred. The stratigraphic position of this interval of trace metal anomalies matches events associated with OAE2 and indicates that intermittent hydrothermal activity on a massive scale triggered abrupt changes in carbon burial and deep ocean oxygen contents.

Rare earth elements in the Mediterranean Sea and mixing in the Mediterranean outflow

Mediterranean surface waters contain elevated levels of the rare earth elements compared to similar nutrient-depleted open ocean waters. Application of a flux balance model shows that the Mediterranean is a net sink for Ce and a net source for the other REE. The abundance pattern of the excess REE required for mass balance is enriched in heavy REE and has a negative Ce anomaly. This supports a marine, possibly coastal, source for the REE. Although the magnitudes of the fluxes involved are consistent with aeolian input, an aeolian source would require large-scale removal of Ce and the light REE within the Mediterranean Sea. A mixing model to compute trace metal anomalies in the Mediterranean outflow predicts the observed REE concentrations well. This implies that Ce behaves conservatively in outflow waters over the calculated one-month period for Mediterranean water to reach the study site. Application to other trace metals gives good agreement for Al, Cd and Mn.

Trace metal anomalies in surface soils and vegetation on two active island volcanoes: stromboli and vulcano (Italy)

The distribution of trace metals was investigated for two active volcanoes (Stromboli and Vulcano). As previously found at Mt. Etna, soil and vegetation Hg data were different from those of Hawaiian, African and Icelandic volcanoes. In contrast to previous hypotheses, the present data suggest that it is highly improbable that the active volcanoes of southern Italy constitute the principal Hg source to the Mediterranean basin. As regards other metals, probably the most significant impact on the terrestrial and coastal environment of southern Vulcano can be attributed to the lavas of the Primordial Vulcano, which have a very high content of Cu and other metals.

Trace metal enrichments in the Mediterranean Sea

Copper, nickel, and cadmium occur at higher concentrations in the surface waters of the Mediterranean than in nutrient-depleted waters of the open ocean. Trace metal profiles have been taken on both sides of the Strait of Gibraltar to constrain a mass balance. Deep Mediterranean waters have trace metal levels comparable to surface waters in regions of Mediterranean deep water formation, implying a minimal role for vertical transport by biological activity. Excess trace metals are not present in open-Atlantic source waters, but a detailed map of trace metal distributions in the Alboran Sea (immediately east of the Strait) reveals a metal-enriched plume with concentrations as high as copper, 3.6 nmol/kg; nickel, 2.8 nmol/kg; and cadmium, 120 pmol/kg. A substantial enrichment in trace metal concentrations therefore can occur in transit from the open Atlantic through the coastal zone into the Strait. This trace metal enrichment may derive either from river inflow (masked by evaporation), diffusion out of continental shelf sediments, eolian particulate fallout, or anthropogenic sources. Metal sources (fluvial, sedimentary, or atmospheric; natural or anthropogenic) are difficult to discern from the large-scale oceanographic distribution. Metal retention in nutrient-depleted surface waters is not due to unusual metal fluxes relative to nutrients, but instead is a consequence of less frequent recycling of nutrients in the Mediterranean compared to the open ocean. Metal enrichments would be expected before human intervention, with anthropogenic input reflected in proportion to the relative augmentation of inputs over natural levels. Mediterranean water produces small trace metal anomalies in the outflow core (positive for Ni, negative for Cd). Present observations are consistent with this prediction, but high precision data would be necessary to observe these at distance from Gibraltar.

Detailed lake sediment geochemistry of anomalous lakes on the nechako plateau, Central British Columbia — comparison of trace metal distributions in capoose and fish lakes

Following completion of a regional geochemical survey on the Nechako Plateau B.C., follow-up studies were undertaken at Capoose and Fish Lakes, representing two contrasting limnological environments, in proximity to chalcopyrite-molybdenite occurrences. Sediments of Capoose Lake, a large oligotrophic body, are characterized by accumulation of hydrous iron and manganese oxides and a low organic matter content (average 6.7%). Fish lake is a small dystrophic to eutrophic lake with organic-rich sediments. Regional trace metal anomalies in sediments are recognised in both lakes. Greatest accumulation of metals characterizes a zone within 20 to 100 m of shore and immediately downslope of mineral occurrences. Anomalous distribution patterns within Capoose Lake appear to result from metal deposition from groundwaters emerging near the base of the nearshore slope, the copper and molybdenum being scavenged primarily by amorphous and crystalline iron oxides, respectively. Scavenging by organic matter promotes anomalous metal accumulations in Fish Lake. Accumulation of metal-rich elastics, particularly clay minerals, in proximity to inflowing streams can also be demonstrated for lead anomalies in Capoose Lake where the closest source of anomalous lead is 11 km upstream. However, deposition of elastic sediments by streams can also dilute anomalies. The Cordillera provides an excellent environment for studying base metal anomalies in lake sediments. Active mechanical and hydromorphic transport processes operating within drainage basins promote the formation of metal-rich zones which are easily recognized. These can be used similarly to detailed soil surveys to determine probable zones of metal enrichment within the catchment area.