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Effect of activated sludge treatment on the formation of N–nitrosamines under different chloramination conditions

Journal of environmental sciences 2022年第7期34卷 242-252页

作者： Xiaolu Zhang Daekyun Kim Tanju Karanfil department of environmental Engineering and earth sciences Clemson UniversityAndersonSC 29625USA

Municipal wastewater discharge is considered as one of the main sources of N-nitrosamine precursors which can impact the qualities of downstream source waters and reclaimed wastewaters for potable reuse. N –Nitrosamine precursors can be removed to various degrees during biological wastewater treatment(e.g., the activated sludge(AS) process). So far, little is known about the impact of the AS process on N-nitrosamine formation under practical disinfection condition(e.g., uniform formation condition(UFC)). In this study, N-nitrosamine UFC from selected model compounds, sewage components(i.e., blackwaters and greywaters) and sewage samples were comprehensively investigated during batch AS treatment tests. N –Nitrosodimethylamine(NDMA) formation from the tested precursor compounds(i.e., trimethylamine(TMA) and sumatriptan(SMTR)) under UFC chloramination decreased mostly after 6 or 24 hr treatment with different types of AS(i.e., domestic rural AS, domestic urban AS, and textile AS), and the reductions in NDMA UFC were comparable to their NDMA formation potential(FP) reductions. In urine and feces blackwaters, NDMA UFC increased after 6 or 24 hr treatment with the domestic(i.e., rural and urban) AS, while NDMA FP decreased substantially. The increases in NDMA UFC after AS treatment was presumably attributed to the removal of bulk organic matters(e.g., dissolved organic carbon(DOC)) which favored NDMA formation under UFC. On the other hand, in laundry greywaters having relatively abundant DOC, N-nitrosamine UFC was less affected by DOC removal before or after AS treatment, but decreased to similar degrees with N-nitrosamine FP. In sewage samples collected from wastewater treatment plants, N-nitrosamines UFC tended to increase or remain constant during AS treatment, despite the decreases in their FPs. These results suggest that biological wastewater treatment(e.g., the AS process) may not effectively reduce N-nitrosamine formation(e.g., measured under UFC) partially because the concurrent removal of bulk organic matters

关键词： Disinfection by-products N–Nitrosamine formation potential Uniform formation condition(UFC) Sewage components Biological wastewater treatment

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全球红树林制图进入主流时代

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Science Bulletin 2023年第19期68卷 2145-2147,M0003页

作者： Daniel A.Friess department of earth and environmental sciences Tulane UniversityNew Orleans LA 70118USA

Mangrove forests have long been considered one of the world’s most threatened ecosystems.This is despite their importance as a social-ecological system due to the ecosystem goods and benefits they provide to coastal communities,from the provision of food and fuel,to coastal protection and pollutant assimilation,to cultural ecosystem services such as recreation and spiritual value.

关键词： coastal assimilation ecosystem

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Distribution of Chancelloriids in a Middle Cambrian Carbonate Platform Deposit, Taebaek Group, Korea

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Acta Geologica Sinica(English Edition) 2016年第3期90卷 783-795页

作者： HONG Jongsun CHOH Suk-Joo LEE Dong-Jin department of earth and environmental sciences Korea University department of earth and environmental sciences Andong National University

The onset of the Cambrian witnessed the diversification of ＂small shelly fossils （SSF）＂, which affected carbonate depositional system. One of the problematic SSF, chancelloriids, are common components of the early to middle Cambrian carbonate and shale, and their contributions toward Cambrian carbonates are not yet fully understood. This study assesses distribution patterns of chancelloriid sclerites in the Cambrian Series 3 Daegi Formation based on microfacies analysis and discusses their sedimentologic implications. In the lower part of the formation, partially articulated chancelloriid sclerites occur mainly in bioclastic packstone and grainstone facies, with isolated sclerite rays in nodular packstone to grainstone facies. In the middle part of the formation, chancelloriid fragments occur only sporadically in bioclastic wackestone to packstone, bioclastic grainstone and oolitic packstone to grainstone facies, whereas boundstone facies are nearly devoid of their fragments. There are no chancelloriid fragments in the upper part of the formation, which consists of oolitic packstone to grainstone facies. Chancelloriids are interpreted to have primarily occupied platform margin shoal environments, shedding their sclerites to surrounding areas, and thus contributed as sediment producers. The distribution of Daegi chancelloriid sclerites is similar to other Cambrian examples, with the exception of common chancelloriids in Cambrian Series 2 reefs and their apparent near absence in the Daegi and other Cambrian Series 3 reefs. This disparity resulted from changes in the ecologic niche of chancelloriids after the end-Cambrian Series 2 reef crisis, coupled with an overall decline of chancelloriids in the middle Cambrian.

关键词： Cambrian Series 3 chancelloriid shoal carbonate platform reef

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等深流沉积:物理海洋学、过程沉积学和石油地质学

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石油勘探与开发 2017年第2期44卷 177-195页

作者： SHANMUGAM G department of earth and environmental sciences The University of Texas at Arlington

主要阐述与等深流沉积以及其他底流沉积相关的基本原理。深海底流分为温盐引起的自转型等深流、风力驱动底流、潮汐驱动底流(大多在海底峡谷)、内波/内潮汐驱动的斜压流4种基本类型,均常见牵引构造。等深流沉积是温盐引起的自转型等深... 详细信息

主要阐述与等深流沉积以及其他底流沉积相关的基本原理。深海底流分为温盐引起的自转型等深流、风力驱动底流、潮汐驱动底流(大多在海底峡谷)、内波/内潮汐驱动的斜压流4种基本类型,均常见牵引构造。等深流沉积是温盐引起的自转型等深流沉积体,粒级可为泥级或细砂级,含硅质或钙质碎屑。在古代等深流与其他等深流的区分方面,目前尚无沉积学或地震学诊断标准。在岩心和露头上,双黏土层是识别深海潮汐沉积的可靠指标。加的斯湾虽然是泥质等深流沉积相模式的代表,但并无真正的等深流沉积,仅受与地中海流出水(MOW)有关的短暂等深流影响,并受内波和内潮汐、浊流、海啸、飓风、泥火山、煤成气渗漏、沉积物供给、孔隙水排出和海底地形等其他复杂因素的影响。在加的斯湾综合大洋钻探(IODP)339项目岩心中没有发现能用于解释沉积过程的原生沉积构造,因此等深流沉积相模式应予废弃。4类底流改造砂体均具备成为油气储集层的潜力。在佛罗里达海峡大巴哈马浅滩(Great Bahama Bank)附近的等深流沉积,因为其中的泥质成分被强烈的等深流从粒间原生孔隙中簸选出来,最大测量孔隙度为40%,最大渗透率达9 881×10^(-3)μm^2。现代等深流的实证数据也显示其具有发育盖层和烃源岩的潜力。因此,未来石油勘探与开发应重点关注这些经常被忽视的深海硅质和钙质碎屑等深流沉积储集层。

关键词：底流等深流沉积储集层加的斯湾佛罗里达海流牵引构造过程沉积学

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Geographic distribution of arsenic contamination in the Himalayan Rivers flowing through Pakistan: Implications for its natural source and effects of anthropogenic activities

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International Journal of Sediment Research 2023年第4期38卷 543-555页

作者： Ishtiaque Hussain Hafiz Ur.Rehman Takaaki Itai Junaid Ali Khattak Abida Farooqi environmental Geochemistry Laboratory Department of Environmental Sciences Faculty of Biological Sciences Quaid-i-Azam University department of environmental sciences University of Baltistan Skardu Graduate School of sciences and Engineering Kagoshima University department of earth and Planetary environmental Science (UG) Graduate School of Science The University of Tokyo department of earth and Planetary Physics (UG) Graduate School of Science The University of Tokyo department of earth and Planetary Science (GR) Graduate School of Science The University of Tokyo

Arsenic(As) in natural hydrological systems is known as a worldwide major environmental concern. A geochemical and sedimentological study was done to ascertain the origin and geographical distribution of As in surface water and fluvial sediment collected from the floodplains/basins of the River Indus and its four major tributaries that drain through the northern Pakistan. The hydrogeochemical compositions of all five rivers were similar with calcium(Ca2+) and bicarbonate(HCO3-) being the dominating ions. The concentration of As ranged from 0.62-24.05 μg/L(average 3.7 ± 3.5 μg/L, n = 61) in river water, 2.3-23.4 mg/kg(average 5.7 ± 3.9 mg/kg) in suspended sediment, and 2.0-13 mg/kg(average4.13 ± 2.3 mg/kg) in fluvial sediment. Various approaches were used, including mineralogical, sequential extraction, geochemical, and statistical analyses to investigate the distribution, behavior, and potential sources of As in the sediment. The effect of geological factors on the distribution of As was also studied.No noticeable changes in the relative abundance of minerals were observed in the sediment at different locations along the river. Both mineralogical and statistical analyses showed that silicate minerals like muscovite, biotite, and chloride are the main As reservoir while oxides minerals like hematite and magnetite, which are minor components in the sediment are second largest As carrier. A geochemical baseline, using the normalization and cumulative frequency distribution curves was constructed for As.The estimated mean human contribution of As was 3.4% in the Indus River, 1.9% in the Jhelum River, 13.7%in the Chenab River, 17.5% in the Ravi River and 5.4% in the Sutlej River, indicating relatively higher effects of anthropogenic activity along the Chenab River and Ravi River. The almost negligible effects of anthropogenic activities were additionally confirmed through the pollution assessment parameters estimated from the geo-enrichment, contamination factors, and accumulation index analyses. The current data sugg

关键词： Arsenic Indus basin Geochemical baseline Source Contamination assessment

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Deformation at low and high stress-loading rates

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Geoscience Frontiers 2019年第1期10卷 43-54页

作者： Claudia A.Trepmann Lina Seybold department of earth and environmental sciences Ludwig-Maximilians University

In an extensional shear zone in the Talea Ori, Crete, quartz veins occur in high-pressure low-temperature metamorphic sediments at sites of dilation along shear band boundaries, kink band boundaries and boudin necks. Bent elongate grains grown epitactically from the host rock with abundant fluid inclusion trails parallel to the vein wall indicate vein formation by crack-seal increments during dissolutionprecipitation creep of the host rock. The presence of sutured high-angle grain boundaries and subgrains shows that temperatures were sufficiently high for recovery and strain-induced grain boundary migration, i.e. higher than 300 -350℃, close to peak metamorphic conditions. The generally low amount of strain accumulated by dislocation creep in quartz of the host rock and most veins indicates low bulk stress conditions of a few tens of MPa on a long term. The time scale of stress-loading to cause cyclic cracking and sealing is assumed to be lower than the Maxwell relaxation time of the metasediments undergoing dissolution-precipitation creep at high strain rates(10^(-10) s^(-1) to 10^(-9) s^(-1)), which is on the order of hundred years. In contrast, some veins discordant or concordant to the foliation show heterogeneous quartz microstructures with micro-shear zones, sub-basal deformation lamellae, shortwavelength undulatory extinction and recrystallized grains restricted to high strain zones. These microstructures indicate dislocation glide-controlled crystal-plastic deformation(low-temperature plasticity) at transient high stresses of a few hundred MPa with subsequent recovery and strain-induced grain boundary migration at relaxing stresses and temperatures of at least 300 -350℃. High differential stresses in rocks at greenschist-facies conditions that relieve stress by creep on the long term, requires fast stress-loading rates, presumably by seismic activity in the overlying upper crust. The time scale for stress loading is controlled by the duration of the slip event along a fault, i.e. a few seconds to minutes.

关键词： High-stress crystal plasticity Crack-seal Seismic cycle Stress-loading rates Talea Ori Crete

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Mineral Inclusions in Chromite from the Chromite Deposit in the Kudi Ophiolite,Tibet,Proto-Tethys

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Acta Geologica Sinica(English Edition) 2017年第2期91卷 469-485页

作者： LIU Jianguo HATTORI Keiko WANG Jian College of earth sciences Jilin University department of earth and environmental sciences University of Ottawa

High-Al chromite from the Kudi chromitites contains a wide range of mineral inclusions. They include clinopyroxene, amphibole, phlogopite, olivine, orthopyroxene, apatite, base-metal sulfides, calcite and brucite. The modal abundance of inclusions vary greatly among different grains of chromite. The common inclusions are clinopyroxene and amphibole, which occur as monomineral or polymineral associated with other minerals. The shapes of these inclusions tend to follow the growth plane of host chromite. Mineral assemblages and textures demonstrate that some inclusions（olivine, clinopyroxene） are trapped during magmatic stage, and most of the inclusions（e.g., amphibole, phlogopite） are trapped during recrystallization of chromite. Sulfide inclusions are pentlandite, chalcopyrite and cubanite. They occur either as isolated grains or together with silicate minerals, and formed from the separation of sulfide-bearing liquid from silicate magma. The parental magma of chromitites contains Al2O3 15.0wt%–16.5wt%, TiO20.30wt%–1.05wt% based on calculation with the composition of chromite, similar to parental magma of high-Al chromitites from elsewhere and the estimated melt composition is comparable with that of MORB. Considering the high-Mg olivine in disseminated chromitite and abundant hydrous inclusions, we propose that Kudi chromitites formed beneath a volcanic front during the subduction initiation of Proto-Tethys.

关键词： chromitite volcanic front sub-arc Northern Kunlun Tibet Proto-Tethys

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Assessing the utility of dissolved organic matter photoreactivity as a predictor of in situ methylmercury concentration

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Journal of environmental sciences 2018年第6期30卷 160-168页

作者： Sara J.Klapstein Susan E.Ziegler David A.Risk Nelson J.O'Driscoll environmental Science Program Memorial University of Newfoundland department of earth sciences St. Francis Xavier University department of earth and environmental Science Acadia University

Methylmercury（MeHg） bioaccumulation is a growing concern in ecosystems worldwide. The absorption of solar radiation by dissolved organic matter（DOM） and other photoreactive ligands can convert MeHg into less toxic forms of mercury through photodemethylation. In this study, spectral changes and photoreactivity of DOM were measured to assess the potential to control photoreactions and predict in situ MeHg concentration. Water samples collected from a series of lakes in southwestern Nova Scotia in June, August, and September were exposed to controlled ultraviolet-A（UV-A） radiation for up to 24 hr. Dissolved organic matter photoreactivity, measured as the loss of absorbance at 350 nm at constant UV-A irradiation, was positively dependent on the initial DOM concentration in lake waters（r^2=0.94）. This relationship was consistent over time with both DOM concentration and photoreactivity increasing from summer into fall across lakes. Lake in situ MeHg concentration was positively correlated with DOM concentration and likely catchment transport in June（r = 0.77） but not the other sampling months. Despite a consistent seasonal variation in both DOM and Fe, and their respective correlations with MeHg, no discernable seasonal trend in MeHg was observed. However, a 3-year dataset from the 6 study lakes revealed a positive correlation between DOM concentration and both Fe（r = 0.91） and MeHg concentrations（r = 0.51） suggesting a more dominant landscape mobility control on MeHg.The DOM-MeHg relationships observed in these lakes highlights the need to examine DOM photoreactivity controls on MeHg transport and availability in natural waters particularly given future climate perturbations.

关键词： Methylmercury Dissolved organic carbon Photoreactions Kejimkujik National Park Freshwater lakes

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The hyperpycnite problem

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Journal of Palaeogeography 2018年第3期7卷 197-238页

作者： G.Shanmugam department of earth and environmental sciences The University of Texas at Arlington

Sedimentologic, oceanographic, and hydraulic engineering publications on hyperpycnal flows claim that （1） river flows transform into turbidity currents at plunge points near the shoreline, （2） hyperpycnal flows have the power to erode the seafloor and cause submarine canyons, and, （3） hyperpycnal flows are efficient in transporting sand across the shelf and can deliver sediments into the deep sea for developing submarine fans. Importantly, these claims do have economic implications for the petroleum industry for predicting sandy reservoirs in deep-water petroleum exploration. However, these claims are based strictly on experimental or theoretical basis, without the supporting empirical data from modern depositional systems. Therefore, the primary purpose of this article is to rigorously evaluate the merits of these claims. A global evaluation of density plumes, based on 26 case studies （e.g., Yellow River, Yangtze River, Copper River, Hugli River （Ganges）, Guadalquivir River, Rio de ]a Plata Estuary, Zambezi River, among others）, suggests a complex variability in nature. Real-world examples show that density plumes （1） occur in six different environments （i.e., marine, lacustrine, estuarine, lagoon, bay, and reef）; （2） are composed of six different compositional materials （e.g., siliciclastic, calciclastic, planktonic, etc.）; （3） derive material from 11 different sources （e.g., river flood, tidal estuary, subglacial, etc.）; （4） are subjected to 15 different external controls （e.g., tidal shear fronts, ocean currents, cyclones, tsunamis, etc.）; and, （5） exhibit 24 configurations （e.g., lobate, coalescing, linear, swirly, U-Turn, anastomosing, etc.）. Major problem areas are：（1） There are at least 16 types of hyperpycnal flows （e.g., density flow, underflow, high-density hyperpycnal plume, high-turbid mass flow, tide-modulated hyperpycnal flow, cyclone-induced hyperpycnal turbidity current, multi-layer hyperpycnal flows, etc.）, without an underpinning principle of fluid dynamics. （2） The basic tenet that river curr

关键词： Density plumes Facies model Hyperpycnites Submarine fans Tidal shear fronts Ocean currents Turbiditycurrents Yellow River Yangtze River

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Reefs in the Early Paleozoic Taebaek Group,Korea:A Review

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Acta Geologica Sinica(English Edition) 2016年第1期90卷 352-367页

作者： LEE Jeong-Hyun HONG Jongsun WOO Jusun OH Jae-Ryong LEE Dong-Jin CHOH Suk-Joo department of earth and environmental sciences Korea University department of earth and Planetary sciences University of Tennessee Division of Polar earth-System sciences Korea Polar Research Institute department of earth and environmental sciences Andong National University

Various early Paleozoic （Cambrian Series 3-Middle Ordovician） reefs are found in the Taebaek Group, eastern Korea, located in the eastern margin of the Sino-Korean Block. They occur in every carbonate-dominant lithostratigraphic unit of the group, but their morphology and composition differ markedly. The Daegi Formation （middle Cambrian： Cambrian Series 3） contains siliceous sponge-Epiphyton reefs formed in a shallow subtidal environment, which is one of the earliest metazoan-bearing microbial reefs after the archaeocyath extinction. The Hwajeol Formation （upper Cambrian： Furongian） encloses sporadic dendrolites consisting of Angulocellularia, which developed in a relatively deep subtidal environment, representing a rare deeper water example. The onset of the Ordovician radiation resulted in the formation of microbialite-Archaeoscyphia-calathiid patch reefs in shallow subtidal deposits of the Lower Ordovician Dumugol Formation. Subsequent late Early Ordovician relative sea-level fall established extensive peritidal environments, forming microbial mats and stromatolites of the Lower-Middle Ordovician Makgol Formation. Ensuing Ordovician radiation resulted in one of the earliest metazoan skeletal reefs of the Middle Ordovician Duwibong Formation, constructed by stromatoporoid Cystostroma and bryozoan Nicholsonella, and developed around shallow shoals. These reefs reflect ongoing evolution and sea-level change during the early Paleozoic, and exemplify a rare glimpse of peri-Gondwanan records of reef evolution, which warrant detailed investigations and comparison with their counterparts in other regions.

关键词： carbonate sedimentology metazoans stromatolites Porifera Cambrian-Ordovician Taebaeksan Basin Korea

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