Particulate Mercury and Particulate Organic Matter in the Itenez Basin (Bolivia)

In rivers and other freshwater bodies, the presence of mercury can be due to direct contamination by anthropic activities such as gold mining. However, it can also be attributed to atmospheric deposition and erosion, runoff, or lixiviation from surrounding soils. In the case of the Amazon rainforest, high mercury contents have been reported for litter and topsoil, which could affect the mercury concentrations in water bodies. Samples of suspended particulate matter were obtained from a transect of the Itenez River, associated lakes, and some of its tributaries. The aim was to obtain information on particulate mercury’s origin in the study area and determine the relationship between particulate mercury and particulate organic carbon. The concentration of mercury, organic matter, and the C:N ratio of the suspended matter was determined. The concentration of particulate mercury by water volume depended on changes in suspended matter loads, which in turn were mostly affected by the nature of the watershed or sediment resuspension. The observed values for the percentage of organic matter and the C:N ratio suggest that most of the mercury content in rivers and lakes originated from soils. A positive correlation was found between mercury concentration by weight of particulate matter and organic carbon content in particles. This correlation might be due to the direct binding of mercury to organic matter through functional groups like thiols or to an indirect effect of oxyhydroxides that can adsorb mercury and are associated with organic matter.

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Seasonal Transport Characteristics of Suspended Particulate Organic Carbon in the Middle and Lower Yangtze River and the Relationship with Three Georges Reservoir

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.663.1058 ◽

2013 ◽

Vol 663 ◽

pp. 1058-1063 ◽

Cited By ~ 1

Author(s):

Xiao Li Liu ◽

Shou Ye Yang ◽

Wen Rui Huang ◽

Lin Lu Li ◽

Chen Zeng ◽

...

Keyword(s):

Grain Size ◽

Organic Matter ◽

Particulate Matter ◽

Organic Carbon ◽

Particulate Organic Carbon ◽

Suspended Matter ◽

Yangtze River ◽

Three Gorges ◽

The Three Gorges ◽

Suspended Particulate

The suspended matter samples collected about 2 times every month in Datong of Yangtze River from May to November 2010 were used for determination of grain size and particulate organic carbon (POC) component. The results indicated that the size composition and organic carbon concentrations of Datong showed obvious seasonal characteristics. The median grain size of the suspended particulate matter ranged from 5.8 to 7.8Φ, decreased in summer (July to September) and increased in autumn (October to November). The POC% of the suspended particulate matter ranged from 0.87% to 1.18%, and was lower in summer, because high sediment discharge had dilution effect for organic carbon. The increase of the turbidity of water reduced the production capacity, and the organic matter correspondingly decreased. POC% decreased with the reduction of median grain size, which suggested that organic matter into the river in summer is mainly organic debris, but not mainly absorbed by the fine particles of clay. CaCO3 content ranged 3.7% to 7.6% and was higher in summer, which reflected the increased source contribution of the upper stream. It decreased in autumn, which reflected the increased source contribution of the middle and lower stream. Since the impoundment of the Three Gorges Reservoir, POC% in Datong were significantly higher than before, which showed the rise of fine particulate matter component and its stronger adsorption of organic matter. The Three Gorges Dam had significant influence on the grain size and organic composition of suspended matter of theYangtze River into the sea. Its potential environmental impact of bio-geochemical effects deserves more research attention.

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Impact of soil use on aggregate stability and its relationship with soil organic carbon at two different altitudes in the Colombian Andes

Agronomía Colombiana ◽

10.15446/agron.colomb.v37n3.77601 ◽

2019 ◽

Vol 37 (3) ◽

pp. 263-273

Author(s):

Efraín Francisco Visconti-Moreno ◽

Ibonne Geaneth Valenzuela-Balcázar

Keyword(s):

Organic Matter ◽

Organic Carbon ◽

Soil Organic Carbon ◽

Aggregate Stability ◽

Tropical Climate ◽

Mineral Particle ◽

Organic Carbon Content ◽

Rice Soils ◽

Organic Matter Pool ◽

Different Altitudes

The stability of soil aggregates depends on the organic matter, and the soil use and management can affect the soil organicmatter (SOM) content. Therefore, it is necessary to know therelationship between aggregate stability and the content of SOMin different types of soil use at two different altitudes of theColombian Andes. This study examined the conditions of soilaggregate stability expressed as a distribution of the size classes of stable aggregates (SA) and of the mean weighted diameter of the stable aggregates (MWD). To correlate these characteristics with the soil organic carbon (OC), we measured the particulate organic matter pool (POC), the OC associated with the mineral organic matter pool (HOC), the total organic carbon content (TOC), and the humification rate (HR). Soils were sampled at two altitudes: 1) Humic Dystrudepts in a cold tropical climate (CC) with three plots: tropical mountain rainforest, pastures, and crops; 2) Fluvaquentic Dystrudepts in a warm tropical climate (WC) with three plots: tropical rainforest, an association of oil palm and pastures, and irrigated rice. Soils were sampled at three depths: 0-5, 5-10 and 10-20 cm. The physical properties, mineral particle size distribution, and bulk density were measured. The content of SA with size>2.36 mm was higher in the CC soil (51.48%) than in the WC soil (9.23%). The SA with size 1.18-2.36 mm was also higher in the CC soil (7.78%) than in the WC soil (0.62%). The SA with size 0.60-1.18 mm resulted indifferent. The SA with size between 0.30 and 0.60 mm were higher in the WC soil (13.95%) than in the CC soil (4.67%). The SA<0.30 mm was higher in the WC soil (72.56%) than in the CC soil (32.15%). It was observed that MWD and the SA>2.36 mm increased linearly with a higher POC, but decreased linearly with a higher HR. For the SA<0.30 mm, a linear decrease was observed at a higher POC, while it increased at a higher HR.

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Short-Term Decomposition and Nutrient-Supplying Ability of Sewage Sludge Digestate, Digestate Compost, and Vermicompost on Acidic Sandy and Calcareous Loamy Soils

Agronomy ◽

10.3390/agronomy11112249 ◽

2021 ◽

Vol 11 (11) ◽

pp. 2249

Author(s):

Nikolett Uzinger ◽

Orsolya Szécsy ◽

Nóra Szűcs-Vásárhelyi ◽

István Padra ◽

Dániel Benjámin Sándor ◽

...

Keyword(s):

Organic Matter ◽

Sewage Sludge ◽

Organic Carbon ◽

Carbon Content ◽

Plant Biomass ◽

Test Plant ◽

Organic Carbon Content ◽

Short Term ◽

Mineral N ◽

Average Residual

Organic waste and the compost and vermicompost derived from it may have different agronomic values, but little work is available on this aspect of sewage sludge. A 75-day pot experiment with perennial ryegrass (Lolium perenne) as the test plant aimed to investigate the fertiliser value and organic matter replenishment capacity of digested sewage sludge (DS) and the compost (COM) and vermicompost (VC) made from it, applied in 1% and 3% doses on acidic sand and calcareous loam. The NPK content and availability, changes in organic carbon content and plant biomass, and the efficiency of the amendments as nitrogen fertilisers were investigated. The final average residual carbon content for DS, COM, and VC was 35 ± 34, 85 ± 46, and 55 ± 46%, respectively. The organic carbon mineralisation rate depended on the soil type. The additives induced significant N mineralisation in both soils: the average increment in mineral N content was 1.7 times the total added N on acidic sand and 4.2 times it on calcareous loam for the 1% dose. The agronomic efficiency of COM and VC as fertilisers was lower than that of DS. In the short term, DS proved to be the best fertiliser, while COM was the best for organic matter replenishment.

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Effect of Tillage System and Organic Matter Management Interactions on Soil Chemical Properties and Biological Activity in a Spring Wheat Short-Time Cultivation

Energies ◽

10.3390/en14217451 ◽

2021 ◽

Vol 14 (21) ◽

pp. 7451

Author(s):

Barbara Breza-Boruta ◽

Karol Kotwica ◽

Justyna Bauza-Kaszewska

Keyword(s):

Organic Matter ◽

Biological Activity ◽

Organic Carbon ◽

Spring Wheat ◽

Chemical Properties ◽

Soil Samples ◽

Available Phosphorus ◽

Organic Carbon Content ◽

Tillage System ◽

Short Time

Properly selected tillage methods and management of the available organic matter resources are considered important measures to enable farming in accordance with the principles of sustainable agriculture. Depending on the depth and intensity of cultivation, tillage practices affect soil chemical composition, structure and biological activity. The three-year experiment was performed on the soil under spring wheat (cv. Tybalt) short-time cultivation. The influence of different tillage systems and stubble management on the soil’s chemical and biological parameters was analyzed. Organic carbon content (OC); content of biologically available phosphorus (Pa), potassium (Ka), and magnesium (Mg); content of total nitrogen (TN), mineral nitrogen forms: N-NO3 and N-NH4 were determined in various soil samples. Moreover, the total number of microorganisms (TNM), bacteria (B), actinobacteria (A), fungi (F); soil respiratory activity (SR); and pH in 1 M KCl (pH) were also investigated. The results show that organic matter amendment is of greater influence on soil characteristics than the tillage system applied. Manure application, as well as leaving the straw in the field, resulted in higher amounts of organic carbon and biologically available potassium. A significant increase in the number of soil microorganisms was also observed in soil samples from the experimental plots including this procedure.

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Characterization of organic matter from a stratigraphic sequence intercepted by the Nemo-1X well, Mozambique: Potential for hydrocarbon generation

Energy Exploration & Exploitation ◽

10.1177/0144598717753920 ◽

2018 ◽

Vol 36 (5) ◽

pp. 1157-1171

Author(s):

Agostinho Mussa ◽

Deolinda Flores ◽

Joana Ribeiro ◽

Ana MP Mizusaki ◽

Mónica Chamussa ◽

...

Keyword(s):

Organic Matter ◽

Organic Carbon ◽

Total Organic Carbon ◽

Hydrocarbon Exploration ◽

Published Data ◽

Organic Carbon Content ◽

Hydrocarbon Generation ◽

Offshore Area ◽

Type Iii ◽

Kerogen Type

The Mozambique Basin, which occurs onshore and offshore in the central and southern parts of Mozambique, contains a thick sequence of volcanic and sedimentary rocks that range in age from the Jurassic to Cenozoic. This basin, along with the Rovuma basin to the north, has been the main target for hydrocarbon exploration; however, published data on hydrocarbon occurrences do not exist. In this context, the present study aims to contribute to the understanding of the nature of the organic matter of a sedimentary sequence intercepted by the Nemo-1X exploration well located in the offshore area of the Mozambique Basin. The well reached a depth of 4127 m, and 33 samples were collected from a depth of 2219–3676 m ranging in age from early to Late Cretaceous. In this study, petrographic and geochemical analytical methods were applied to assess the level of vitrinite reflectance and the organic matter type as well as the total organic carbon, total sulfur, and CaCO3 contents. The results show that the total organic carbon content ranges from 0.41 to 1.34 wt%, with the highest values determined in the samples from the Lower Domo Shale and Sena Formations, which may be related to the presence of the solid bitumens that occur in the carbonate fraction of those samples. The vitrinite random reflectances range from 0.65 to 0.86%Rrandom, suggesting that the organic matter in all of the samples is in the peak phase of the “oil generation window” (0.65–0.9%Rrandom). The organic matter is mainly composed of vitrinite and inertinite macerals, with a minor contribution of sporinite from the liptinite group, which is typical of kerogen type III. Although all of the samples have vitrinite reflectances corresponding to the oil window, the formation of liquid hydrocarbons is rather limited because the organic matter is dominated by gas-prone kerogen type III.

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Sources of organic matter in first flush runoff from urban roadways

Water Science & Technology ◽

10.2166/wst.2015.307 ◽

2015 ◽

Vol 72 (7) ◽

pp. 1234-1242 ◽

Cited By ~ 2

Author(s):

K. Wada ◽

N. Takei ◽

T. Sato ◽

H. Tsuno

Keyword(s):

Particle Size ◽

Organic Matter ◽

Organic Carbon ◽

Carbon Content ◽

Road Dust ◽

Organic Carbon Content ◽

Water Mixture ◽

First Flush ◽

The Road ◽

Organic Carbon Concentration

This study aims to explore the influential sources of organic matter in first flush runoff from urban roadways by comparing organic carbon content and particle size distribution in road dust with those from discharge from vehicles during rainfall. Samples on first flush runoff and road dust were collected from urban roadways. In addition, vehicle drainage was assumed to flow from vehicles during rainfall events, so vehicle wash-off water was collected by spraying water onto the top and from the underside of vehicles to simulate accumulation during a vehicle run. In road dust, the organic carbon content in the <0.2 mm fraction was about twice that of the 0.2–2 mm fraction. The particle size distributions of both first flush runoff and vehicle wash-off water were similar, and particles <0.2 mm contributed to over 95% of the total volume. The dissolved organic carbon concentration in the vehicle wash-off water was considerably higher than that in the road dust/water mixture. The total organic carbon content in road dust was positively correlated with annual daily traffic. Therefore, vehicles were thought to strongly influence the nature of road dust.

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Analysis of Fracturing Ability Factors of Tight Reservoir

E3S Web of Conferences ◽

10.1051/e3sconf/202016501004 ◽

2020 ◽

Vol 165 ◽

pp. 01004

Author(s):

Zhenhua Li ◽

Ke Gai ◽

Feng Cao

Keyword(s):

Fracture Toughness ◽

Organic Matter ◽

Organic Carbon ◽

Oil And Gas ◽

Sedimentary Environment ◽

Economic Benefits ◽

Natural Fracture ◽

Organic Carbon Content ◽

Multi Stage ◽

Tight Reservoir

Fracturing ability is the characteristic used to measure whether the tight reservoir could be effectively fractured and form network in the process of hydraulic fracturing in order to improve the production of oil and gas. Research shows that the more brittle the reservoir is, the weaker the fracture toughness is, the more developed the natural fracture is, the higher the maturity of organic matter is, the lower the organic carbon content is, and the better the fracturing ability is. In addition, factors such as crustal stress, sedimentary environment and internal structure of the reservoir also affect the fracturing ability. The analysis of reservoir fracturing ability plays a key role in the strata selection, multi-stage fracturing design and prediction of oilfield economic benefits.

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Understanding Effects of OAE 2 in the Marginal-marine Environment: A Multi-proxy approach from Bagh Beds, Western India

10.5194/egusphere-egu2020-964 ◽

2020 ◽

Author(s):

Bikash Ranjan Sahu ◽

Sohom Roy ◽

Prasanta Sanyal

Keyword(s):

Organic Matter ◽

Organic Carbon ◽

Marine Environment ◽

Nutrient Dynamics ◽

Isotope Composition ◽

Western India ◽

Organic Carbon Content ◽

Terrestrial Environment ◽

Shallow Marine ◽

Carbon Reservoir

The Cenomanian-Turonian (C/T) Oceanic Anoxic Event 2 (OAE 2) at ~94 million years ago was characterized by severe depletion in marine water oxygen levels and extreme perturbations in the carbon cycle at a global scale that lasted for 5 to 6-million years. However, wealth of the data comes mainly from deep marine records, hugely limiting our understanding on the contemporaneous terrestrial environmental conditions. Here, we present major and trace element concentrations, carbon isotope composition of carbonates (&#948;13Ccarb) and organic matter (&#948;13Cbulk), organic carbon content (TOC), and biomarker composition from a ~20 m thick well-preserved shallow marine sequence from the Bagh Beds in Uchad, western India in order to investigate the nutrient dynamics, productivity variations and carbon reservoir perturbations in shallow marine as well as in terrestrial environment. Based on litho-stratigraphy, the Uchad section is divided into Lower Cenomanian, Turonian and Upper Coniacian units. A total of ~5&#8240; increase in the &#948;13Ccarb and 0.07% in TOC values and a sharp 1.7&#8240; decrease in the &#948;13Cbulk values in Lower Cenomanian suggest large changes in organic carbon recycling before the advent of OAE 2. Higher terrigenous influx and micro-nutrient supply in the lower parts is also suggested from relatively higher concentrations of Al, Ti, Th, Fe, Zn, Ni and K, although their concentrations decrease rapidly above the C/T boundary. Significant correlation observed between &#948;13Cbulk and &#948;13Ccarb (r=0.51, p=0.03) supports an authigenic organic matter production in the shallow marine environment. However, minor enrichments in redox-sensitive elements like Mo, V and U observed above the C/T boundary probably suggest that the shallow marine region was relatively less affected during the initial anoxic phases. Lack of correlation between redox-sensitive elements and Al or Ti concentrations (r <0.12) suggest that there is minimal influence of detrital supply on recycling of U, V and Mo. Interestingly, Lower Turonian units show large positive excursions in redox-sensitive elements as well as increases in U/Th, Ni/Co and V/(V+Ni) values, which are succeeded by a major decrease in &#948;13Ccarb values (7.6&#8240;) and increase in the TOC values by 0.15%, thereby suggesting occurrence of a more expanded episode of anoxia in Lower Turonian that perturbed the shallow marine carbon reservoir. Ba/Al ratios are variable throughout the section, although large positive spikes preceding and succeeding the anoxic phases suggest a causal link between organic matter productivity and anoxia.

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Organic carbon determination in histosols and soil horizons with high organic matter content from Brazil

Scientia Agricola ◽

10.1590/s0103-90162006000200012 ◽

2006 ◽

Vol 63 (2) ◽

pp. 187-193 ◽

Cited By ~ 15

Author(s):

Marcos Gervasio Pereira ◽

Gustavo Souza Valladares ◽

Lúcia Helena Cunha dos Anjos ◽

Vinícius de Melo Benites ◽

Ademar Espíndula Jr. ◽

...

Keyword(s):

Organic Matter ◽

Organic Carbon ◽

Organic Matter Content ◽

Analysis Data ◽

Matter Content ◽

Organic Soils ◽

Organic Carbon Content ◽

Muffle Furnace ◽

Soil Taxonomy ◽

High Organic Carbon Content

Soil taxonomy systems distinguish mineral soils from organic soils based on the amount of soil organic carbon. Procedures adopted in soil surveys for organic carbon measurement are therefore of major importance to classify the soils, and to correlate their properties with data from other studies. To evaluate different methods for measuring organic carbon and organic matter content in Histosols and soils with histic horizons, from different regions of Brazil, 53 soil samples were comparatively analyzed by the methods of Walkley & Black (modified), Embrapa, Yeomans & Bremner, modified Yeomans & Bremner, muffle furnace, and CHN. The modified Walkley & Black (C-W & B md) and the combustion of organic matter in the muffle furnace (OM-Muffle) were the most suitable for the samples with high organic carbon content. Based on regression analysis data, the OM-muffle may be estimated from C-W & B md by applying a factor that ranges from 2.00 to 2.19 with 95% of probability. The factor 2.10, the average value, is suggested to convert results obtained by these methods.

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