scholarly journals Spatial distribution and offshore export of total organic carbon along the eastern boundary of the Subtropical North Pacific

2011 ◽  
Vol 2 (2) ◽  
pp. 93
Author(s):  
C.G. Castro ◽  
C.A. Collins ◽  
J.T. Pennington ◽  
D. Zúñiga ◽  
F.P. Chavez
Keyword(s):  
Organic Carbon ◽  
Total Organic Carbon ◽  
Surface Waters ◽  
Average Rate ◽  
California Current ◽  
Early Summer ◽  
Ekman Transport ◽  
Minimum Zone ◽  
Production Increase ◽  
First Time

Data collected in February, 2003, along the upper continental slope of western North America between Monterey Bay, California (37°N, 122°W), and Cabo San Lucas, Mexico (23°N, 118°W), document, for the first time, the alongshore distribution of total organic carbon (TOC). Highest TOC concentrations (>70 µM) were observed for waters above the nitracline and associated with both California Current and southern surface waters. The northward advection of tropical waters in the California Undercurrent did not have any discernible impact on TOC distributions. An estimate of the average rate at which TOC in surface waters was exported offshore by Ekman transport in February 2003 was 1.73 × 103 kg C yr−1 for each meter of coastline. The offshore flux estimate is thought to be conservative with respect to the annual mean offshore flux because the offshore Ekman transport and primary production increase in late spring and early summer and the contribution of upwelling filaments has not been considered. Analysis of TOC contributions to pelagic respiration suggested that TOC accounted for 45% of the oxygen decrease in southern oxic waters. In California Current and oxygen minimum zone waters, TOC did not contribute to pelagic respiration.

Approaches to Regulating Organic Carbon and the Necessity of Its Obligatory Monitoring in Drinking Water

2020 ◽  
pp. 61-66
Author(s):  
IA Khlystov ◽  
DA Schukina ◽  
EA Kuzmina ◽  
EG Plotko ◽  
LА Brusnicyna
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Organic Carbon ◽  
Total Organic Carbon ◽  
Surface Waters ◽  
Distribution System ◽  
Design Stage ◽  
Treatment Technique ◽  
Important Indicator ◽  
By Products

Background: Current accumulation of organogenic elements in surface waters is mainly attributed to intensive anthropogenic activities. Waterborne organic matter may endanger human health when using surface waters for drinking and recreational purposes. Applied techniques of water treatment fail to ensure complete water purification and part of organic substances (their low molecular weight fraction) still remains. Chlorination of drinking water can generate a variety of halogenated by-products having adverse health effects in humans including carcinogenic ones. Our objective was to substantiate the reference value for total organic carbon (TOC) in water disinfected by chlorine. Materials and methods: We analyzed the results of laboratory testing of surface and treated water samples taken in Yekaterinburg in 2013–2014 and 2017, carried out health risk assessment, and built predicative models of by-products formation. Results: We established that, following chlorination, TOC concentrations became 1.5 times lower while chloroform and total trihalomethane concentrations became 24.5–80.2 and 22.9–54.5 times higher than initial values, respectively. The most significant non-carcinogenic risks were estimated for children aged 0-6 years from exposures to chloroform (HQ = 1.150). Individual carcinogenic risks from exposures to bromoform and dibromochloromethane as measured in water before its supplying to the distribution system, referred to the first value range (less than 1×10–6) while risks from bromodichloromethane and chloroform exposures fell in the second range (from 1×10–6 to 1×10–4). The mathematical model of the correlation between predictors (temperature, reaction time, pH, and certain chemical compounds) and levels of by-products was built. Conclusions: Our model makes it possible to predict generation of organochlorine compounds at the design stage of water treatment technique. Total organic carbon is an important indicator that should be monitored at the stages of water treatment to ensure safety of drinking water and efficiency of its disinfection.

scholarly journals The conservative behavior of dissolved organic carbon in surface waters of the southern Chukchi Sea, Arctic Ocean, during early summer

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Kazuki Tanaka ◽  
Nobuyuki Takesue ◽  
Jun Nishioka ◽  
Yoshiko Kondo ◽  
Atsushi Ooki ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Arctic Ocean ◽  
Surface Waters ◽  
Chukchi Sea ◽  
Early Summer

A modified advanced Fenton process for industrial wastewater treatment

2007 ◽  
Vol 55 (12) ◽  
pp. 59-65 ◽  
Author(s):  
A.G. Chakinala ◽  
D.H. Bremner ◽  
A.E. Burgess ◽  
K.C. Namkung
Keyword(s):  
Wastewater Treatment ◽  
Organic Carbon ◽  
Total Organic Carbon ◽  
Industrial Wastewater ◽  
Hydrodynamic Cavitation ◽  
H2o2 Concentration ◽  
Fenton Process ◽  
Batch Experiments ◽  
Wastewater Samples ◽  
First Time

For the first time hydrodynamic cavitation induced by a liquid whistle reactor (LWR) has been used in conjunction with the advanced Fenton process (AFP) for the treatment of industrial wastewater. Semi-batch experiments in the LWR were designed to investigate the performance of the process by optimising various parameters such as pressure, pH, H2O2 concentration and the concentration of industrial wastewater samples on the mineralisation of the total organic carbon (TOC). It was found that higher pressures are more favourable for a rapid TOC mineralisation.

Seston Ecology of the Surface Waters of Hudson Bay

1980 ◽  
Vol 37 (12) ◽  
pp. 2242-2253 ◽  
Author(s):  
J. T. Anderson ◽  
J. C. Roff
Keyword(s):  
Organic Carbon ◽  
Chlorophyll A ◽  
Surface Waters ◽  
Nitrogen Limitation ◽  
Grazing Pressure ◽  
Hudson Bay ◽  
Carbon And Nitrogen ◽  
First Time ◽  
Temperature Depth ◽  
Carbon:Nitrogen Ratios

The planktonic biomass variables, chlorophyll a, ATP, particulate organic carbon, and nitrogen have been measured in surface waters throughout Hudson Bay for the first time. On the basis of these variables Hudson Bay can be regarded as oligotrophc during the summer months. Clear inshore–offshore gradients of biomass were evident showing significant correlations in transects to salinity, temperature, depth, and distance from shore. Chlorophyll a values were always low, averaging 0.09 mg m−3 offshore and 0.28 mg m−3 inshore. ATP averaged 0.072 mg m−3 offshore and twice as high inshore. Biomass ratios also demonstrated clear inshore–offshore gradients; carbon:nitrogen ratios ranged from 4.9:1 inshore to 12.5:1 offshore indicating nitrogen limitation of offshore waters. Chlorophyll a: phaeopigment ratios decreased and biocarbon:chlorophyll a ratios increased offshore indicating an increased proportion of heterotrophs and possibly higher relative grazing pressure offshore. For the inshore areas, biomass and probably productivity were highest and significantly correlated to runoff with the exception of the Southampton–Coats–Mansel islands area, which is influenced by waters from Foxe Channel and Hudson Strait. While Hudson Bay meets most of the criteria for arctic classification, its character is sufficiently different to warrant special status.Key words: Hudson Bay, seston ecology, chlorophyll a, biomass ratios, phaeopigments, plankton

Characterization of Nova Scotia surface waters and treatment options for removal of colour and trihalomethane precursors

1996 ◽  
Vol 23 (6) ◽  
pp. 1316-1325 ◽  
Author(s):  
D. H. Waller ◽  
M. J. MacPhee ◽  
P. W. Prendiville ◽  
R. F. McCurdy ◽  
A. W. Gates ◽  
...  
Keyword(s):  
Nova Scotia ◽  
Organic Carbon ◽  
Total Organic Carbon ◽  
Surface Waters ◽  
Carbon Surface ◽  
Raw Water ◽  
Dissolved Air Flotation ◽  
Direct Filtration ◽  
Air Flotation ◽  
Dissolved Air

This paper provides an overview of the results of a study undertaken to provide a basis for predesign evaluation of the effectiveness of options for treatment of municipal surface waters in the province of Nova Scotia. Seasonal samples of raw water were obtained from the fall of 1992 through the fall of 1993 from five sites. Results were compared with a Nova Scotia Department of Health data base of randomly collected samples. For project samples, strong relationships were evident between raw water total organic carbon (TOC) and both colour and trihalomethane formation potential. Laboratory batch tests, supported by plant results, indicated that percentage removals of TOC increase with raw water TOC, and that settling-filtration was more effective than direct filtration for waters with higher raw TOC concentrations. Results of solids settling tests were consistent with TOC results. A treatment optimized for TOC removal also ensured removal of colour. TOC removals by dissolved air flotation followed by filtration exceeded removals by direct filtration or settling-filtration, based on laboratory bench tests, particularly at sites with higher values of raw TOC. Colour removal by dissolved air flotation was consistently higher at all sites. Key words: enhanced coagulation, trihalomethane precursors, total organic carbon, surface water treatment, dissolved air flotation.

The Carbon:²³⁴Thorium ratios of sinking particles in the California Current Ecosystem 2: Examination of a thorium sorption, desorption, and particle transport model

2019 ◽  
Author(s):  
Michael Stukel ◽  
Thomas Kelly
Keyword(s):  
Organic Carbon ◽  
Water Column ◽  
Particulate Organic Carbon ◽  
Transport Model ◽  
California Current ◽  
In Situ Measurements ◽  
Power Law Distribution ◽  
Sinking Particles ◽  
Organic Carbon Concentration

Thorium-234 (234Th) is a powerful tracer of particle dynamics and the biological pump in the surface ocean; however, variability in carbon:thorium ratios of sinking particles adds substantial uncertainty to estimates of organic carbon export. We coupled a mechanistic thorium sorption and desorption model to a one-dimensional particle sinking model that uses realistic particle settling velocity spectra. The model generates estimates of 238U-234Th disequilibrium, particulate organic carbon concentration, and the C:234Th ratio of sinking particles, which are then compared to in situ measurements from quasi-Lagrangian studies conducted on six cruises in the California Current Ecosystem. Broad patterns observed in in situ measurements, including decreasing C:234Th ratios with depth and a strong correlation between sinking C:234Th and the ratio of vertically-integrated particulate organic carbon (POC) to vertically-integrated total water column 234Th, were accurately recovered by models assuming either a power law distribution of sinking speeds or a double log normal distribution of sinking speeds. Simulations suggested that the observed decrease in C:234Th with depth may be driven by preferential remineralization of carbon by particle-attached microbes. However, an alternate model structure featuring complete consumption and/or disaggregation of particles by mesozooplankton (e.g. no preferential remineralization of carbon) was also able to simulate decreasing C:234Th with depth (although the decrease was weaker), driven by 234Th adsorption onto slowly sinking particles. Model results also suggest that during bloom decays C:234Th ratios of sinking particles should be higher than expected (based on contemporaneous water column POC), because high settling velocities minimize carbon remineralization during sinking.

CHARACTERISATION OF DISSOLVED ORGANIC CARBON (DOC) LEACHED FROM LEAVES IN WATER

2008 ◽  
Vol 6 (1) ◽  
Author(s):  
Markus Heryanto Langsa
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Total Organic Carbon ◽  
Gas Chromatography Mass Spectrometry ◽  
Pyrolysis Gas ◽  
Pyrolysis Gas Chromatography ◽  
Chromatography Mass Spectrometry ◽  
Pinus Radiate

<p>Penelitian ini bertujuan untuk menentukan senyawa organik khususnya organic karbon terlarut (DOC) dari dua spesies daun tumbuhan (<em>wandoo eucalyptus </em>and <em>pinus radiate, conifer</em>) yang larut dalam air selama periode 5 bulan leaching eksperimen. Kecepatan melarutnya senyawa organic ditentukan secara kuantitatif dan kualitatif menggunakan kombinasi dari beberapa teknik diantaranya Total Organic Carbon (TOC) analyser, Ultraviolet-Visible (UV-VIS) spektrokopi dan pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS).</p><p>Hasil analisis DOC dan UV menunjukkan peningkatan yang tajam dari kelarutan senyawa organic di awal periode pengamatan yang selanjutnya berkurang seiring dengan waktu secara eksponensial. Jumlah relatif senyawa organic yang terlarut tergantung pada luas permukaan, aktifitas mikrobiologi dan jenis sampel tumbuhan (segar atau kering) yang digunakan. Fluktuasi profil DOC dan UV<sub>254</sub> disebabkan oleh aktifitas mikrobiologi. Diperoleh bahwa daun kering lebih mudah terdegradasi menghasilkan senyawa organic dalam air dibandingkan dengan daun segar. Hasil pyrolysis secara umum menunjukkan bahwa senyawa hidrokarbon aromatic dan fenol (dan turunannya) lebih banyak ditemukan pada residue sampel setelah proses leaching kemungkinan karena adanya senyawa lignin atau aktifitas humifikasi mikrobiologi membuktikan bahwa senyawa-senyawa tersebut merupakan komponen penting dalam proses karakterisasi DOC.</p>

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