Dissolved Metal (Fe, Mn, Zn, Ni, Cu, Co, Cd, Pb) and Metalloid (As, Sb) in Snow Water across a 2800 km Latitudinal Profile of Western Siberia: Impact of Local Pollution and Global Transfer

Snow cover is known to be an efficient and unique natural archive of atmospheric input and an indicator of ecosystem status. In high latitude regions, thawing of snow provides a sizable contribution of dissolved trace metals to the hydrological network. Towards a better understanding of natural and anthropogenic control on heavy metals and metalloid input from the atmosphere to the inland waters of Siberian arctic and subarctic regions, we measured chemical composition of dissolved (<0.22 µm) fractions of snow across a 2800 km south–north gradient in Western Siberia. Iron, Mn, Co, Ni, and Cd demonstrated sizable (by a factor of 4–7) decrease in concentration northward, which can be explained by a decrease in overall population density and the influence of dry aerosol deposition. Many elements (Mn, Ni, Cu, Cd, Pb, As, and Sb) exhibited a prominent local maximum (a factor of 2–3) in the zone of intensive oil and gas extraction (61–62° N latitudinal belt), which can be linked to gas flaring and fly ash deposition. Overall, the snow water chemical composition reflected both local and global (long-range) atmospheric transfer processes. Based on mass balance calculation, we demonstrate that the winter time atmospheric input represents sizable contribution to the riverine export fluxes of dissolved (<0.45 µm) Mn, Co, Zn, Cd, Pb, and Sb during springtime and can appreciably shape the hydrochemical composition of the Ob River main stem and tributaries.

Stable Silicon Isotopes Uncover a Mineralogical Control on the Benthic Silicon Cycle in the Arctic Barents Sea

Biogeochemical cycling of silicon (Si) in the Barents Sea is under considerable pressure from physical and chemical changes, including dramatic warming and sea ice retreat, together with a decline in dissolved silicic acid (DSi) concentrations of Atlantic inflow waters since 1990. Moreover, further expansion of the Atlantic realm (termed `Atlantification') is expected to shift phytoplankton community compositions away from diatom-dominated spring bloomsin favour of Atlantic flagellate species (coccolithophore-dominated). The changes in pelagic primary production will alter the composition of the material comprising the depositional flux, which will subsequently in influence the recycling processes at and within the seafloor. In this study we assess the predominant controls on the early diagenetic cycling of Si, a key nutrient in marine ecosystems, by combining stable isotopic analysis of pore water DSi and of operationally defined reactive pools of the solid phase. We show that low biogenic silica (BSi) contents (0.39-0.52 wt% or 92-185 μmol g dry wt-1) drive correspondingly low asymptotic concentrations of pore water DSi (~100 μM). However, while these surface sediments appear almost devoid of BSi, we present evidence for the rapid recycling of bloom derived BSi that generates striking transient peaks in sediment pore water [DSi], which is a feature that is subject to future shifts in phytoplankton community compositions. Using a simple mass balance calculation we show that the pore water DSi pool is supplemented by a lithogenic Si source (LSi), while our sediment pore water Si isotopic profiles also uncover a coupling of the iron (Fe) and Si cycles. This has previously been observed in lower latitude marine sediment systems and thus provides further support for a redox influence on oceanic pore water DSi. We suggest that a high LSi:BSi ratio and apparent Fe (oxyhydr)oxide influence could lead to a degree of stability in the annual background benthic flux of DSi despite the pressures on pelagic phytoplankton communities. Coupled with supporting isotopic evidence for the precipitation of authigenic clays in Barents Sea sediment cores, our observations have implications for the sink vs recycling terms in the regional Si budget.

Evaluasi Neraca Massa Kolom Deethanizer di Unit Gas Plant

Gas Plant Unit in company X engaged in energy in Balikpapan has a design capacity of 560 tons/day. This unit serves to produce propane gas (C3H8) and butane (C4H10) to become LPG products. The Deethanizer column is a Light End fractionation unit that separates Ethane compounds from Propane and Butane at operating temperature resulting in LPG products that meet the specifications. The researcher's goal is to obtain the actual mass balance calculation and the flow rate of the process—the method used from retrieving data on operating conditions directly to the industry and performing calculations. The Deetanizer column is composed of 40 sieve trays, the entry feed of the 20th tray operates at the mass flow rate of the Deethanizer column feed of 5949,184 kg/hour, the flow rate of LPG products is 3428,334 kg/hour, and the mass flow rate of gas overhead is 150,186 kg/hour so that there is an actual % loss of 39,84%, this is because this unit should be time to be repaired. However, this does not affect the products produced, which can be seen from laboratory tests on LPG product samples.ABSTRAKGas Plant Unit diperusahaan X yang bergerak dibidang energi di Balikpapan mempunyai kapasitas desain 560 ton/hari. Unit ini berfungsi untuk memproduksi gas propane (C3H8) dan butana (C4H10) sehingga menjadi produk LPG. Kolom Deethanizer adalah unit fraksinasi Light Ends yang berfungsi untuk memisahkan senyawa Ethana dari Propana dan Butana dengan proses destilasi bertekananan sehingga menghasilkan produk LPG yang memenuhi spesifikasi. Tujuan peneliti untuk mendapatkan perhitungan neraca massa aktual serta laju alir proses. Metode yang digunakan dari pengambilan data kondisi operasi langsung ke industri serta melakukan perhitungan. Kolom Deetanizer tersusun dari 40 buah sieve tray, umpan masuk dari tray ke-20, beroperasi pada laju alir massa umpan kolom Deethanizer sebesar 5949,184 kg/jam, laju alir produk LPG sebesar 3428,334 kg/jam dan laju alir massa overhead gas sebesar 150,186 kg/jam sehingga diperoleh % yield aktual 57.62 dan % losses aktual sebesar 39,84%, hal ini disebabkan karena unit ini seharusnya sudah waktunya untuk di perbaiki. Namun hal ini tidak berpengaruh terhadap produk yang dihasilkan, hal ini dapat dilihat dari hasil uji Laboratorium mengenai Sampel Produk LPG.

Geodetic Mass Balance of the South Shetland Islands Ice Caps, Antarctica, from Differencing TanDEM-X DEMs

Although the glaciers in the Antarctic periphery currently modestly contribute to sea level rise, their contribution is projected to increase substantially until the end of the 21st century. The South Shetland Islands (SSI), located to the north of the Antarctic Peninsula, are lacking a geodetic mass balance calculation for the entire archipelago. We estimated its geodetic mass balance over a 3–4-year period within 2013–2017. Our estimation is based on remotely sensed multispectral and interferometric SAR data covering 96% of the glacierized areas of the islands considered in our study and 73% of the total glacierized area of the SSI archipelago (Elephant, Clarence, and Smith Islands were excluded due to data limitations). Our results show a close to balance, slightly negative average specific mass balance for the whole area of −0.106 ± 0.007 m w.e. a−1, representing a mass change of −238 ± 12 Mt a−1. These results are consistent with a wider scale geodetic mass balance estimation and with glaciological mass balance measurements at SSI locations for the same study period. They are also consistent with the cooling trend observed in the region between 1998 and the mid-2010s.

Oil Retention in Shales: A Review of the Mechanism, Controls and Assessment

Shale oil is a vital alternative energy source for oil and gas and has recently received an extensive attention. Characterization of the shale oil content provides an important guiding significance for resource potential evaluation, sweet spot prediction, and development of shale oil. In this paper, the mechanism, evaluation and influencing factors of oil retention in shales are reviewed. Oil is retained in shales through adsorption and swelling of kerogen, adsorption onto minerals and storage in shale pores. Quite a few methods are developed for oil content evaluation, such as three-dimensional fluorescence quantitation, two-dimensional nuclear magnetic resonance (2D NMR), solvent extraction, pyrolysis, multiple extraction-multiple pyrolysis-multiple chromatography, logging calculation, statistical regression, pyrolysis simulation experiment, and mass balance calculation. However, the limitations of these methods represent a challenge in practical applications. On this basis, the influencing factors of the oil retention are summarized from the microscale to the macroscale. The oil retention capacity is comprehensively controlled by organic matter abundance, type and maturity, mineral composition and diagenesis, oil storage space, shale thickness, and preservation conditions. Finally, oil mobility evaluation methods are introduced, mainly including the multitemperature pyrolysis, 2D NMR, and adsorption-swelling experiment, and the influencing factors of movable shale oil are briefly discussed. The aim of this paper is to deepen the understanding of shale oil evaluation and provide a basis for further research.

Interpreting the Chemical Variability of Iron Smelting Slag: A Case Study from Northeastern Madagascar

The archaeological remains of a metallurgical workshop were excavated at Amboronala (northeast of Madagascar/1000–1200 CE). The bulk mineralogical (X-ray Diffraction) and chemical (X-ray Fluorescence) data on ores, building materials, and slag are used to carry out a mass balance calculation. The results show an important variability from one smelt to the other, reflecting a poorly controlled process. During each smelt, a given amount of building material contributes to the formation of the slag, and the conditions of reduction allow the extraction of a given amount of metal. These two main factors influence the composition of the slag independently and variably. This finding allows to make some inference on the origin of the technique and the organization of the production can be made.

Removal of perchlorate by a lab-scale constructed wetland using achira (Canna indica L.)

Achira (Canna indica L.) has not yet been tested for its potential in removing perchlorate (ClO4−) from wastewater. In this study, constructed wetlands with and without achira were used to investigate the removal efficiency and removal mechanism of perchlorate. The results showed that more ClO4− was removed by the wetlands with achira relative to those without. Perchlorate removal in the wetlands without achira decreased with time, whereas perchlorate in the wetlands with achira was stably removed. In terms of ClO4− content, the achira tissues were in the descending order of: leaf > aerial stem > flower or rhizome > root. Perchlorate was concentrated in leaves (more than 55.8%) rather than in root (less than 0.67%). Mass balance calculation showed that plant uptake accounted for 5.81–7.34% of initial ClO4− input, while microbial degradation accounted for 29.39–62.48%. The wetlands with achira were favorable for soil microorganism growth and proliferation and in turn ClO4− biodegradation. Furthermore, the effluent pH increased in achira wetland columns and in turn promoting ClO4− removal. The results indicating that the wetlands with achira promote ClO4− removal by improving the rhizosphere environment.

Geology, Rock Geochemistry and Ore Fluid Characteristics of the Brambang Copper-Gold Porphyry Prospect, Lombok Island, Indonesia.

Brambang is one of the porphyry copper-gold prospects/deposits situated along eastern Sunda arc. This study is aimed to understand geological framework, alteration geochemistry and ore fluid characteristics of the prospect. Fieldworks and various laboratory analyses were performed including petrography, ore microscopy, rock geochemistry, chlorite chemistry and fluid inclusion microthermometry. The prospect is composed of andesitic tuff and diorite which are intruded by tonalite porphyries. Tonalite porphyries are interpreted as ore mineralisation-bearing intrusion. Various hydrothermal alterations are identified including potassic, phyllic, propylitic, advanced argillic and argillic types. Ore mineralisation is characterized by magnetite and copper sulfides such as bornite and chalcopyrite. Potassic alteration is typified by secondary biotite, and associated with ore mineralisation. Mass balance calculation indicates SiO2, Fe2O3, K2O, Cu and Au are added during potassic alteration process. Ore forming fluid is dominated by magmatic fluid at high temperature (450-600ºC) and high salinity (60-70 wt. % NaCl eq.). Hydrothermal fluid was diluted by meteoric water incursion at low-moderate temperature of 150-400ºC and salinity of 0.5-7 wt. % NaCl eq.

Understanding the evolution of atmospheric nitrous oxide over the last century from the stable isotopes of the firn air at Styx Glacier, East Antarctica

&lt;p&gt;The increase in mixing ratio of greenhouse gas (GHG) has been believed to be the primary driver for the ongoing global warming. Among the GHGs, the mixing ratio of nitrous oxide (N&lt;sub&gt;2&lt;/sub&gt;O) has increased by 23% since 1750 CE. N&lt;sub&gt;2&lt;/sub&gt;O has a long residence time of ca. 120 years, and a potential to destruct the ozone layer. The Global Warming Potential of N&lt;sub&gt;2&lt;/sub&gt;O is about 300 times greater than that of CO&lt;sub&gt;2&lt;/sub&gt; over 100 years. However, the temporal changes in magnitude and geographic distribution of different N&lt;sub&gt;2&lt;/sub&gt;O sources are uncertain, hence, understanding the dynamics of atmospheric N&lt;sub&gt;2&lt;/sub&gt;O has been a challenge to the researcher during the last few decades. Here, we present new stable isotope data of N&lt;sub&gt;2&lt;/sub&gt;O from the firn air at Styx Glacier, East Antarctica to comprehend the atmospheric evolution for the last 100 years. Our results show that the N&lt;sub&gt;2&lt;/sub&gt;O mixing ratio has increased, whereas the &amp;#948;&lt;sup&gt;15&lt;/sup&gt;N&lt;em&gt;&lt;sup&gt;bulk&lt;/sup&gt;&lt;/em&gt; (&amp;#8240;, AIR) and &amp;#948;&lt;sup&gt;18&lt;/sup&gt;O (&amp;#8240;, VSMOW) values decreased during the last 100 years, consistent with the existing firn air records. The progressive increase in the N&lt;sub&gt;2&lt;/sub&gt;O mixing ratio and the decrease in the isotope ratios suggest a higher contribution from the anthropogenic sources assuming that the N&lt;sub&gt;2&lt;/sub&gt;O flux from the natural sources is constant. Our box model analysis using the stable isotopes and mixing ratio data of N&lt;sub&gt;2&lt;/sub&gt;O of Styx firn air suggests that anthropogenic N&lt;sub&gt;2&lt;/sub&gt;O emission at 2014 CE was ca. 37.5% higher than 1919 CE. The box model calculation with Styx and other firn air and ice core data suggests that in comparison to the pre-industrial era, the total N&lt;sub&gt;2&lt;/sub&gt;O emission is ca. 61% higher at present (2014 CE), where ca. 62% and 38% contributions are from natural and anthropogenic sources, respectively to the total N&lt;sub&gt;2&lt;/sub&gt;O emission. The isotope-based mass-balance calculation indicates that continental emission was ca. 45% higher in 2014 CE than in 1919 CE. Although there is a large scatter in existing data, the site preference of &lt;sup&gt;15&lt;/sup&gt;N in N&lt;sub&gt;2&lt;/sub&gt;O molecules (&amp;#948;&lt;sup&gt;15&lt;/sup&gt;N&lt;em&gt;&lt;sup&gt;SP&lt;/sup&gt;&lt;/em&gt; &amp;#8240;, AIR) shows an increasing trend during the post-industrial era, which is consistent with the idea that enhanced fertilization increased soil N&lt;sub&gt;2&lt;/sub&gt;O emissions by activating nitrification processes.&lt;/p&gt;