AVIRIS Spectrometer Maps Total Water Vapor Column

NASA Technical Reports Server (NTRS)

Conel, James E.; Green, Robert O.; Carrere, Veronique; Margolis, Jack S.; Alley, Ronald E.; Vane, Gregg A.; Bruegge, Carol J.; Gary, Bruce L.

1992-01-01

Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) processes maps of vertical-column abundances of water vapor in atmosphere with good precision and spatial resolution. Maps provide information for meteorology, climatology, and agriculture.

Response of coliform populations in streambed sediment and water column to changes in nutrient concentrations in water.

PubMed

Shelton, D R; Pachepsky, Y A; Kiefer, L A; Blaustein, R A; McCarty, G W; Dao, T H

2014-08-01

As sediments increasingly become recognized as reservoirs of indicator and pathogen microorganisms, an understanding of the persistence of indicator organisms becomes important for assessment and predictions of microbial water quality. The objective of this work was to observe the response of water column and sediment coliform populations to the change in nutrient concentrations in the water column. Survival experiments were conducted in flow-through chambers containing sandy sediments. Bovine feces were collected fresh and introduced into sediment. Sixteen days later, the same fecal material was autoclaved and diluted to provide three levels - 1×, 0.5×, and 0.1× of nutrient concentrations - spike in water column. Total coliforms, Escherichia coli, and total aerobic heterotrophic bacterial concentrations were monitored in water and sediment. Bacteria responded to the nutrient spike with initial growth both in the water column and in sediment. The response of bacterial concentrations in water column was nonlinear, with no significant changes at 0.1 and .5× spikes, but a substantial change at 1× spike. Bacteria in sediment responded to the spikes at all added nutrient levels. Coliform inactivation rates both in sediment and in water after the initial growth occurred, were not significantly different from the inactivation rates before spike. These results indicate that introduction of nutrients into the water column results in nonlinear response of E. coli concentrations both in water and in sediments, followed by the inactivation with the same rate as before introduction of nutrients. Published by Elsevier Ltd.

Water column correction for coral reef studies by remote sensing.

PubMed

Zoffoli, Maria Laura; Frouin, Robert; Kampel, Milton

2014-09-11

Human activity and natural climate trends constitute a major threat to coral reefs worldwide. Models predict a significant reduction in reef spatial extension together with a decline in biodiversity in the relatively near future. In this context, monitoring programs to detect changes in reef ecosystems are essential. In recent years, coral reef mapping using remote sensing data has benefited from instruments with better resolution and computational advances in storage and processing capabilities. However, the water column represents an additional complexity when extracting information from submerged substrates by remote sensing that demands a correction of its effect. In this article, the basic concepts of bottom substrate remote sensing and water column interference are presented. A compendium of methodologies developed to reduce water column effects in coral ecosystems studied by remote sensing that include their salient features, advantages and drawbacks is provided. Finally, algorithms to retrieve the bottom reflectance are applied to simulated data and actual remote sensing imagery and their performance is compared. The available methods are not able to completely eliminate the water column effect, but they can minimize its influence. Choosing the best method depends on the marine environment, available input data and desired outcome or scientific application.

Deuterium used as artificial tracer in column studies under saturated water flow conditions

NASA Astrophysics Data System (ADS)

Koeniger, P.; Geiges, M.; Leibundgut, Ch.

2003-04-01

In contrast to numerous investigations using deuterium as an environmental tracer, hydrological investigations with deuterium-labelled water are rather rare. Currently applications in groundwater studies are restricted due to increasing costs of spiking large water quantities but an application as intelligent tracer might be of advantage especially in combination with other tracers and under distinct environmental conditions. Therefore deuterium was applied as artificial tracer in column experiments that are well proved as a tool to characterise tracer behaviour in recent studies. Deuterium was tested in comparison to the more familiar conservative tracer fluorescein. Varying experimental conditions, e.g. column length (0.5, 1.0, 1.5 m), initial tracer concentration (0.01, 0.02, 0.2 mg) and flow velocity (1.5 to 6.0 m/d) were used to investigate tracer behaviour under saturated water flow conditions. Deuterium was analysed using an H/Device with chrome reduction connected to an isotope ratio mass spectrometer and expressed in relative concentrations [per mill V-SMOW]. Theoretical tracer breakthrough curves were calculated using a one dimensional dispersion model. The results indicate higher mean transport velocities and smaller dispersion for deuterium in all experiments. Due to different molecule properties that also determine the interaction of soil substrate and tracer, deuterium indicates a more conservative transport behaviour. Deuterium is non-toxic, completely soluble, chemically and biologically stable and not subject to light-influenced decay. Furthermore, it shows promise for investigations of water flow in the unsaturated zone, and of interactions of water in soil-plant-atmosphere systems. A further discussion of problems, together with possibilities for applying deuterium as an artificial tracer, will be presented.

Water Column Correction for Coral Reef Studies by Remote Sensing

PubMed Central

Zoffoli, Maria Laura; Frouin, Robert; Kampel, Milton

2014-01-01

Human activity and natural climate trends constitute a major threat to coral reefs worldwide. Models predict a significant reduction in reef spatial extension together with a decline in biodiversity in the relatively near future. In this context, monitoring programs to detect changes in reef ecosystems are essential. In recent years, coral reef mapping using remote sensing data has benefited from instruments with better resolution and computational advances in storage and processing capabilities. However, the water column represents an additional complexity when extracting information from submerged substrates by remote sensing that demands a correction of its effect. In this article, the basic concepts of bottom substrate remote sensing and water column interference are presented. A compendium of methodologies developed to reduce water column effects in coral ecosystems studied by remote sensing that include their salient features, advantages and drawbacks is provided. Finally, algorithms to retrieve the bottom reflectance are applied to simulated data and actual remote sensing imagery and their performance is compared. The available methods are not able to completely eliminate the water column effect, but they can minimize its influence. Choosing the best method depends on the marine environment, available input data and desired outcome or scientific application. PMID:25215941

Dissolved sulfide distributions in the water column and sediment pore waters of the Santa Barbara Basin

USGS Publications Warehouse

Kuwabara, J.S.; VanGeen, A.; McCorkle, D.C.; Bernhard, J.M.

1999-01-01

Dissolved sulfide concentrations in the water column and in sediment pore waters were measured by square-wave voltammetry (nanomolar detection limit) during three cruises to the Santa Barbara Basin in February 1995, November-December 1995, and April 1997. In the water column, sulfide concentrations measured outside the basin averaged 3 ?? 1 nM (n = 28) in the 0 to 600 m depth range. Inside the basin, dissolved sulfides increased to reach values of up to 15 nM at depths >400 m. A suite of box cores and multicores collected at four sites along the northeastern flank of the basin showed considerable range in surficial (400 ??M at 10 cm. Decreases in water-column nitrate below the sill depth indicate nitrate consumption (-55 to -137 ??mole m-2 h-1) similar to nearby Santa Monica Basin. Peaks in pore-water iron concentrations were generally observed between 2 and 5 cm depth with shallowest peaks at the 590 m site. These observations, including observations of the benthic microfauna, suggest that the extent to which the sulfide flux, sustained by elevated pore-water concentrations, reaches the water column may be modulated by the abundance of sulfide-oxidizing bacteria in addition to iron redox and precipitation reactions.

Preliminary Martian Atmospheric Water Vapour Column Abundances with Mars Climate Sounder

NASA Astrophysics Data System (ADS)

Lolachi, Ramin; Irwin, P. G. J.; Teanby, N.; Calcutt, S.; Howett, C. J. A.; Bowles, N. E.; Taylor, F. W.; Schofield, J. T.; Kleinboehl, A.; McCleese, D. J.

2007-12-01

Mars Climate Sounder (MCS) is an infra-red radiometer on board NASA's Mars Reconnaissance Orbiter (MRO) launched in August 2005 and now orbiting Mars in a near circular polar orbit. MCS has nine spectral channels in the range 0.3-50 µm. Goals of MCS include global characterization of atmospheric temperature, dust and water profiles observing temporal and spatial variation. Using Oxford University's multivariate retrieval algorithm, NEMESIS, we present preliminary determinations of the water vapour column abundance in the Martian atmosphere during the period September-October 2006 (Ls range 111-129°, i.e. northern hemisphere summer). A combination of spectral channels inside and outside the water vapour rotation band (at 50 µm) are used to retrieve the column abundances mainly using nadir observations (as aerosol opacity is less important relative to water vapour opacity in nadir viewing geometry). We then compare these column abundances to earlier results from the Viking Orbiter Mars Atmospheric Water Detectors (MAWD) and the Thermal Emission Spectrometer (TES) on Mars Global Surveyor.

Field Validation of Toxicity Tests to Evaluate the Potential for Beneficial Use of Produced Water

DOE Office of Scientific and Technical Information (OSTI.GOV)

Joseph Bidwell; Jonathan Fisher; Naomi Cooper

2008-03-31

was limited to sediment depths of 10 cm or greater, which is outside of the primary zone of biological activity. Further, exposure to site sediments did not have any effects on test organisms, and macroinvertebrate communities did not indicate impairment at the oil production site as compared to a reference site. In situ experiments with H. azteca and C. fluminea, indicated a sublethal site effect (on growth of both species), but these could not be definitively linked with produced water infiltration. Severe weather conditions (drought followed by flooding) negatively influenced the intensity of lake sampling aimed at delineating produced water infiltration. Due to the lack of clear evidence of produced water infiltration into the sub-littoral zone of the lake, it was not possible to assess whether the laboratory bioassays of produced water effectively indicate risk in the receiving system. However, the acutely toxic nature of the produced water and general lack of biological effects in the lake at the oil production site suggest minimal to no produced water infiltration into surficial lake sediments and the near-shore water column. This study was able to demonstrate the utility of ion toxicity modeling to support data from toxicity identification evaluations aimed at identifying key toxic constituents in produced water. This information could be used to prioritize options for treating produced water in order to reduce toxic constituents and enhance options for reuse. The study also demonstrated how geographic information systems, toxicity modeling, and toxicity assessment could be used to facilitate future site assessments.« less

Slow physics: recording the ascent and descent of a water column

NASA Astrophysics Data System (ADS)

Lindén, Johan; Källman, Kjell-Mikael; Holm, Erik

2018-07-01

A glass filled with carbon dioxide gas upside down on a plate of water constitutes an excellent demonstration of the solubility of gases. If the water level on the plate is maintained the CO2 will slowly dissolve and the column of water will rise inside the glass, without quite reaching the ceiling, before an opposite process sets in: the water level will even more slowly begin to sink in a process which will take several years. We followed the process for several months, recording images of the water column with 10 min to 1 h intervals. The physics of the process is discussed and modeled quantitatively.

Mitigating oil spills in the water column

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barry, Edward; Libera, Joseph A.; Mane, Anil U.

The scale and scope of uncontrolled oil spills can be devastating. Diverse marine environments and fragile ecologies are some of the most susceptible to the many ill effects, while the economic costs can be crippling. A notoriously difficult challenge with no known technological solution is the successful removal of oil dispersed in the water column. Here, we address this problem through cheap and reusable oil sorbents based on the chemical modification of polymer foams. Interfacial chemistry was optimized and subsequently tested in a simulated marine environment at the National Oil Spill Response Research & Renewable Energy Test Facility, Ohmsett. Wemore » find favorable performance for surface oil mitigation and, for the first time, demonstrate the advanced sorbent's efficiency and efficacy at pilot scale in extraction of crude oil and refined petroleum products dispersed in the water column. As a result, this is a potentially disruptive technology, opening a new field of environmental science focused on sub-surface pollutant sequestration.« less

Mitigating oil spills in the water column

DOE PAGES

Barry, Edward; Libera, Joseph A.; Mane, Anil U.; ...

2017-10-05

The scale and scope of uncontrolled oil spills can be devastating. Diverse marine environments and fragile ecologies are some of the most susceptible to the many ill effects, while the economic costs can be crippling. A notoriously difficult challenge with no known technological solution is the successful removal of oil dispersed in the water column. Here, we address this problem through cheap and reusable oil sorbents based on the chemical modification of polymer foams. Interfacial chemistry was optimized and subsequently tested in a simulated marine environment at the National Oil Spill Response Research & Renewable Energy Test Facility, Ohmsett. Wemore » find favorable performance for surface oil mitigation and, for the first time, demonstrate the advanced sorbent's efficiency and efficacy at pilot scale in extraction of crude oil and refined petroleum products dispersed in the water column. As a result, this is a potentially disruptive technology, opening a new field of environmental science focused on sub-surface pollutant sequestration.« less

Resistance, resilience and recovery: aquatic bacterial dynamics after water column disturbance.

PubMed

Shade, Ashley; Read, Jordan S; Welkie, David G; Kratz, Timothy K; Wu, Chin H; McMahon, Katherine D

2011-10-01

For lake microbes, water column mixing acts as a disturbance because it homogenizes thermal and chemical gradients known to define the distributions of microbial taxa. Our first objective was to isolate hypothesized drivers of lake bacterial response to water column mixing. To accomplish this, we designed an enclosure experiment with three treatments to independently test key biogeochemical changes induced by mixing: oxygen addition to the hypolimnion, nutrient addition to the epilimnion, and full water column mixing. We used molecular fingerprinting to observe bacterial community dynamics in the treatment and control enclosures, and in ambient lake water. We found that oxygen and nutrient amendments simulated the physical-chemical water column environment following mixing and resulted in similar bacterial communities to the mixing treatment, affirming that these were important drivers of community change. These results demonstrate that specific environmental changes can replicate broad disturbance effects on microbial communities. Our second objective was to characterize bacterial community stability by quantifying community resistance, recovery and resilience to an episodic disturbance. The communities in the nutrient and oxygen amendments changed quickly (had low resistance), but generally matched the control composition by the 10th day after treatment, exhibiting resilience. These results imply that aquatic bacterial assemblages are generally stable in the face of disturbance. © 2011 Society for Applied Microbiology and Blackwell Publishing Ltd.

Methane gas seepage - Disregard of significant water column filter processes?

NASA Astrophysics Data System (ADS)

Schneider von Deimling, Jens; Schmale, Oliver

2016-04-01

Marine methane seepage represents a potential contributor for greenhouse gas in the atmosphere and is discussed as a driver for climate change. The ultimate question is how much methane is released from the seafloor on a global scale and what fraction may reach the atmosphere? Dissolved fluxes from methane seepage sites on the seabed were found to be very efficiently reduced by benthic microbial oxidation, whereas transport of free gas bubbles from the seabed is considered to bypass the effective benthic methane filter. Numerical models are available today to predict the fate of such methane gas bubble release to the water column in regard to gas exchange with the ambient water column, respective bubble lifetime and rise height. However, the fate of rising gas bubbles and dissolved methane in the water column is not only governed by dissolution, but is also affected by lateral oceanographic currents and vertical bubble-induced upwelling, microbial oxidation, and physico-chemical processes that remain poorly understood so far. According to this gap of knowledge we present data from two study sites - the anthropogenic North Sea 22/4b Blowout and the natural Coal Oil point seeps - to shed light into two new processes gathered with hydro-acoustic multibeam water column imaging and microbial investigations. The newly discovered processes are hereafter termed Spiral Vortex and Bubble Transport Mechanism. Spiral Vortex describes the evolution of a complex vortical fluid motion of a bubble plume in the wake of an intense gas release site (Blowout, North Sea). It appears very likely that it dramatically changes the dissolution kinetics of the seep gas bubbles. Bubble Transport Mechanism prescribes the transport of sediment-hosted bacteria into the water column via rising gas bubbles. Both processes act as filter mechanisms in regard to vertical transport of seep related methane, but have not been considered before. Spiral Vortex and Bubble Transport Mechanism represent the

Water column imaging on hydrothermal vent in Central Indian Ridge

NASA Astrophysics Data System (ADS)

Koh, J.; Park, Y.

2017-12-01

Water column imaging with Multibeam echosounder systems (MBES) is recently becoming of increasing interest for oceanographic studies. Especially gas bubbles and hot water exposed from hydrothermal vents make acoustic impedance anomalies in cold seawater, water column imaging is very useful for the researchers who want to detect some kinds of hydrothermal activity. We conducted a hydrothermal exploration program, called "INVENT17", using the MBES system, KONGBERG EM122 (12kHz, 1°×1°), mounted on R/V ISABU and we deployed other equipments including video guided hydraulic grab, tow-yo CTD and general CTD with MAPR (Miniature Autonomous Plume Recorder) in 2017. First, to evaluate its capabilities of detection of hydrothermal vent, the surveys using the MBES were conducted at the Solitaire Field, previously identified hydrothermal area of the Central Indian Ridge. The bathymetric data obtained from MBES provided information about detailed morphology of seafloor, but we were not able to achieve the information from the water column imaging data. But the clue of existence of active hydrothermal vent was detected through the values of ΔNTU, dEh/dt, and OPR gained from MAPR, the data means that the hydrothermal activity affects 100m from the seafloor. It could be the reason that we can't find the hydrothermal activity because the range resolution of water column imaging is pretty rough so that the size of 100m-scaled activity has low possibility to distinguish from seafloor. The other reason is there are no sufficient objects to cause strong scattering like as CO2 bubbles or droplets unlike in the mid-Okinawa Trough. And this suggests that can be a important standard to identify properties of hydrothermal vent sites depending on the presence of scattering objects in water mass. To justify this, we should perform more chemical analysis of hot water emanating from hydrothermal vent and collected several bottles of water sample to do that.

In situ quantitative characterisation of the ocean water column using acoustic multibeam backscatter data

NASA Astrophysics Data System (ADS)

Lamarche, G.; Le Gonidec, Y.; Lucieer, V.; Lurton, X.; Greinert, J.; Dupré, S.; Nau, A.; Heffron, E.; Roche, M.; Ladroit, Y.; Urban, P.

2017-12-01

Detecting liquid, solid or gaseous features in the ocean is generating considerable interest in the geoscience community, because of their potentially high economic values (oil & gas, mining), their significance for environmental management (oil/gas leakage, biodiversity mapping, greenhouse gas monitoring) as well as their potential cultural and traditional values (food, freshwater). Enhancing people's capability to quantify and manage the natural capital present in the ocean water goes hand in hand with the development of marine acoustic technology, as marine echosounders provide the most reliable and technologically advanced means to develop quantitative studies of water column backscatter data. This is not developed to its full capability because (i) of the complexity of the physics involved in relation to the constantly changing marine environment, and (ii) the rapid technological evolution of high resolution multibeam echosounder (MBES) water-column imaging systems. The Water Column Imaging Working Group is working on a series of multibeam echosounder (MBES) water column datasets acquired in a variety of environments, using a range of frequencies, and imaging a number of water-column features such as gas seeps, oil leaks, suspended particulate matter, vegetation and freshwater springs. Access to data from different acoustic frequencies and ocean dynamics enables us to discuss and test multifrequency approaches which is the most promising means to develop a quantitative analysis of the physical properties of acoustic scatterers, providing rigorous cross calibration of the acoustic devices. In addition, high redundancy of multibeam data, such as is available for some datasets, will allow us to develop data processing techniques, leading to quantitative estimates of water column gas seeps. Each of the datasets has supporting ground-truthing data (underwater videos and photos, physical oceanography measurements) which provide information on the origin and

Recycling of drinking water treatment residue as an additional medium in columns for effective P removal from eutrophic surface water.

PubMed

Wang, Changhui; Wu, Yu; Bai, Leilei; Zhao, Yaqian; Yan, Zaisheng; Jiang, Helong; Liu, Xin

2018-07-01

This study assesses the feasibility of recycling drinking water treatment residue (DWTR) to treat eutrophic surface water in a one-year continuous flow column test. Heat-treated DWTR was used as an additional medium (2%-4%) in columns in case excessive organic matter and N were released from the DWTR to surface water. The results indicated that with minimal undesirable effects on other water properties, DWTR addition substantially enhanced P removal, rendering P concentrations in treated water oligotrophic and treated water unsuitable for Microcystis aeruginosa breeding. Long-term stable P removal by DWTR-column treatment was mainly attributed to the relatively low P levels in raw water (<0.108 mg L -1 ) and high P adsorption capability of DWTR, as confirmed by increases in amorphous Al/Fe in DWTR after the tests and low adsorption of P in the mobile forms. The major components of DWTR showed minimal changes, and potential metal pollution from DWTR was not a factor to consider during recycling. DWTR also enriched functional bacterial genera that benefitted biogeochemical cycles and multiple pollution control (e.g., Dechloromonas, Geobacter, Leucobacter, Nitrospira, Rhodoplanes, and Sulfuritalea); an apparent decrease in Mycobacterium with potential pathogenicity was observed in DWTR-columns. Regardless, limited denitrification of DWTR-columns was observed as a result of low bioavailability of C in surface water. This finding indicates that DWTR can be used with other methods to ensure denitrification for enhanced treatment effects. Overall, the use of DWTR as an additional medium in column systems can potentially treat eutrophic surface water. Copyright © 2018 Elsevier Ltd. All rights reserved.

Water Column Variability in Coastal Regions

DTIC Science & Technology

1997-09-30

to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data... 1 . REPORT DATE 30 SEP 1997 2. REPORT TYPE 3. DATES COVERED 00-00-1997 to 00-00-1997 4. TITLE AND SUBTITLE Water Column Variability in...Andrews, Woods, and Kester deployed a spar buoy at a central location in Narragansett Bay to obtain time-series variations at multiple depths ( 1 , 4

INTERNATIONAL SOURCE WATER TOXICITY MONITORING CONSORTIUM

EPA Science Inventory

Many researchers in the field of time-relevant, on-line toxicity monitors for source water protection believe that some mechanism to guide and prioritize research in this emerging field would be beneficial. On-line toxicity monitors are tools designed to screen water quality and ...

An analysis of lethal and sublethal interactions among type I and type II pyrethroid pesticide mixtures using standard Hyalella azteca water column toxicity tests.

PubMed

Hoffmann, Krista Callinan; Deanovic, Linda; Werner, Inge; Stillway, Marie; Fong, Stephanie; Teh, Swee

2016-10-01

A novel 2-tiered analytical approach was used to characterize and quantify interactions between type I and type II pyrethroids in Hyalella azteca using standardized water column toxicity tests. Bifenthrin, permethrin, cyfluthrin, and lambda-cyhalothrin were tested in all possible binary combinations across 6 experiments. All mixtures were analyzed for 4-d lethality, and 2 of the 6 mixtures (permethrin-bifenthrin and permethrin-cyfluthrin) were tested for subchronic 10-d lethality and sublethal effects on swimming motility and growth. Mixtures were initially analyzed for interactions using regression analyses, and subsequently compared with the additive models of concentration addition and independent action to further characterize mixture responses. Negative interactions (antagonistic) were significant in 2 of the 6 mixtures tested, including cyfluthrin-bifenthrin and cyfluthrin-permethrin, but only on the acute 4-d lethality endpoint. In both cases mixture responses fell between the additive models of concentration addition and independent action. All other mixtures were additive across 4-d lethality, and bifenthrin-permethrin and cyfluthrin-permethrin were also additive in terms of subchronic 10-d lethality and sublethal responses. Environ Toxicol Chem 2016;35:2542-2549. © 2016 SETAC. © 2016 SETAC.

In Situ Mo Isotope Fractionation in the Water Columns of Euxinic Basins

NASA Astrophysics Data System (ADS)

Neubert, N.; Nägler, T. F.; Böttcher, M. E.

2007-12-01

The present study investigates for the first time the overall process of molybdenum (Mo) scavenging in modern euxinic systems using Mo concentration and stable isotope measurements. We analyzed samples from three different sites: The Black Sea, the largest permanently euxinic basin, and two anoxic basins of the Baltic Sea, the Gotland Deep and the Landsort Deep which have maximum water depths of 247 m and 459 m, respectively. Water column profiles, as well as surface sediment samples, were recovered from different water depths. Mo is a redox-sensitive trace metal which is soluble as the molybdate oxyanion in oxic seawater with a residence time of about 800 ka. The isotope signature of Mo is a relatively new proxy used to reconstruct the paleo-redox conditions of the Earth's atmosphere and the oceanic system. The Mo isotope composition in seawater is homogeneous (Siebert et al. 2003). Scavenging of Mo under euxinic conditions is related to the amount of free sulfide in the water column. Near total removal of Mo from the water column is reached at aquatic sulfide concentration of c. 11 μM (Erickson and Helz 2000). In the Black Sea this corresponds to a water depth of about 400 m. Sediment samples of the Black Sea from more then 400 m water depth show seawater isotopic composition, in line with the assumption of bulk Mo removal. However, shallower sediments deposited under lower aquatic sulfide concentrations show significant Mo isotope fractionation. The Baltic Sea oceanographic conditions, including temporary bottom water oxygenation due to sporadic North Sea water inflows, are more complex than in the Black Sea. The aquatic sulfide concentration in the water column is less than 5 μM in the two anoxic troughs. As expected from this lower sulfidity, the surface sediments show Mo fractionation similar to the oxic to slightly euxinic sediments of the Black Sea. Our new results on the Mo isotopic composition in euxinic water columns clearly indicate in situ

In situ and laboratory bioassays with Chironomus riparius larvae to assess toxicity of metal contamination in rivers: the relative toxic effect of sediment versus water contamination.

PubMed

Faria, Mafalda S; Lopes, Ricardo J; Nogueira, António J A; Soares, Amadeu M V M

2007-09-01

We used bioassays employing head capsule width and body length increase of Chironomus riparius larvae as end points to evaluate metal contamination in streams. Bioassays were performed in situ near an abandoned Portuguese goldmine in the spring of 2003 and 2004. Bioassays also were performed under laboratory conditions with water and sediment collected from each stream to verify if laboratory bioassays could detect in situ toxicity and to evaluate the relative contribution of sediment and water to overall toxicity. We used field sediments with control water and control sediments with field water to discriminate between metal contamination in water and sediment. Field water with dry and sieved, organic matter-free, and nontreated sediments was used to determine the toxicity of heavy metals that enter the organism through ingested material. In both in situ and laboratory bioassays, body length increase was significantly inhibited by metal contamination, whereas head capsule width was not affected. Body length increase was more affected by contaminated sediment compared to contaminated water. The lowest-effect level of heavy metals was observed in the dry and sieved sediment that prevented ingestion of sediment particles by larvae. These results suggest that body length increase of C. riparius larvae can be used to indicate the impact of metal contamination in rivers. Chironomus riparius larvae are more affected by heavy metals that enter the organism through ingested sediment than by heavy metals dissolved in the water column. Nevertheless, several factors, such as the particle size and organic matter of sediment, must be taken into account.

Locomotive No. 17 coming towards Sand House & Water Column ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Locomotive No. 17 coming towards Sand House & Water Column at south end of the Yard complex - East Broad Top Railroad & Coal Company, State Route 994, West of U.S. Route 522, Rockhill Furnace, Huntingdon County, PA

Effects of slow recovery rates on water column geochemistry in aquitard wells

USGS Publications Warehouse

Schilling, K.E.

2011-01-01

Monitoring wells are often installed in aquitards to verify effectiveness for preventing migration of surface contaminants to underlying aquifers. However, water sampling of aquitard wells presents a challenge due to the slow recovery times for water recharging the wells, which can take as long as weeks, months or years to recharge depending on the sample volume needed. In this study, downhole profiling and sampling of aquitard wells was used to assess geochemical changes that occur in aquitard wells during water level recovery. Wells were sampled on three occasions spanning 11years, 1year and 1week after they were purged and casing water showed substantial water chemistry variations. Temperature decreased with depth, whereas pH and specific conductance increased with depth in the water column after 11years of water level recovery. Less stable parameters such as dissolved O2 (DO) and Eh showed strong zonation in the well column, with DO stratification occurring as the groundwater slowly entered the well. Oxidation of reduced till groundwater along with degassing of CO2 from till pore water affects mineral solubility and dissolved solid concentrations. Recommendations for sampling slowly recovering aquitard wells include identifying the zone of DO and Eh stratification in the well column and collecting water samples from below the boundary to better measure unstable geochemical parameters. ?? 2011 Elsevier Ltd.

An alternative procedure for uranium analysis in drinking water using AQUALIX columns: application to varied French bottled waters.

PubMed

Bouvier-Capely, C; Bonthonneau, J P; Dadache, E; Rebière, F

2014-01-01

The general population is chronically exposed to uranium ((234)U, (235)U, and (238)U) and polonium ((210)Po) mainly through day-to-day food and beverage intake. The measurement of these naturally-occurring radionuclides in drinking water is important to assess their health impact. In this work the applicability of calix[6]arene-derivatives columns for uranium analysis in drinking water was investigated. A simple and effective method was proposed on a specific column called AQUALIX, for the separation and preconcentration of U from drinking water. This procedure is suitable for routine analysis and the analysis time is considerably shortened (around 4h) by combining the separation on AQUALIX with fast ICP-MS measurement. This new method was tested on different French bottled waters (still mineral water, sparkling mineral water, and spring water). Then, the case of simultaneous presence of uranium and polonium in water was considered due to interferences in alpha spectrometry measurement. A protocol was proposed using a first usual step of spontaneous deposition of polonium on silver disc in order to separate Po, followed by the uranium extraction on AQUALIX column before alpha spectrometry counting. © 2013 Published by Elsevier B.V.

Toxicity evaluation of surface water treated with different disinfectants in HepG2 cells.

PubMed

Marabini, Laura; Frigerio, Silvia; Chiesara, Enzo; Radice, Sonia

2006-01-01

It is well known that water disinfection through chlorination causes the formation of a mixture of disinfection by-products (DBPs), many of which are genotoxic and carcinogenic. To demonstrate the formation of such compounds, a pilot water plant supplied with water from Lake Trasimeno was set up at the waterworks of Castiglione del Lago (PG, Italy). The disinfectants, continuously added to pre-filtered lake water flowing into three different basins, were sodium hypochlorite, chlorine dioxide and peracetic acid, an alternative disinfectant used until now for disinfecting waste waters, but not yet studied for a possible use in drinking water treatment. The aim of this study was to evaluate the formation during the disinfection processes of some toxic compounds that could explain the genotoxic effects of drinking waters. Differently treated waters were concentrated by solid-phase adsorption on silica C(18) columns and toxicity was assessed in a line of human hepatoma cells (HepG2), a metabolically competent cellular line very useful for human risk evaluation. The seasonal variability of the physical-chemical water characteristics (AOX, UV 254 nm, potential formation of THM, pH and temperature) made indispensable experimentation with water samples taken during the various seasons. Autumn waters cause greater toxicity compared to those of other seasons, in particular dilution of the concentrate at 0.5l equivalent of disinfected waters with chlorine dioxide and peracetic acid causes a 55% reduction in cellular vitality while the cellular vitality is over 80% with the all other water concentrates. Moreover it is very interesting underline that non-cytotoxic quantities of the autumnal water concentrates cause, after 2h treatment, a decrease in GSH and a statistically significant increase in oxygen radicals, while after prolonged treatment (24h) cause a GSH increase, without variations in the oxygen radical content. This phenomenon could be interpreted as the cellular

Effects of vertical distribution of water vapor and temperature on total column water vapor retrieval error

NASA Technical Reports Server (NTRS)

Sun, Jielun

1993-01-01

Results are presented of a test of the physically based total column water vapor retrieval algorithm of Wentz (1992) for sensitivity to realistic vertical distributions of temperature and water vapor. The ECMWF monthly averaged temperature and humidity fields are used to simulate the spatial pattern of systematic retrieval error of total column water vapor due to this sensitivity. The estimated systematic error is within 0.1 g/sq cm over about 70 percent of the global ocean area; systematic errors greater than 0.3 g/sq cm are expected to exist only over a few well-defined regions, about 3 percent of the global oceans, assuming that the global mean value is unbiased.

A review of oscillating water columns.

PubMed

Heath, T V

2012-01-28

This paper considers the history of oscillating water column (OWC) systems from whistling buoys to grid-connected power generation systems. The power conversion from the wave resource through to electricity via pneumatic and shaft power is discussed in general terms and with specific reference to Voith Hydro Wavegen's land installed marine energy transformer (LIMPET) plant on the Scottish island of Islay and OWC breakwater systems. A report on the progress of other OWC systems and power take-off units under commercial development is given, and the particular challenges faced by OWC developers reviewed.

Benthic Fluxes of Dissolved Macro- and Micronutrients to the Water Column of Upper Klamath Lake, Oregon

NASA Astrophysics Data System (ADS)

Kuwabara, J. S.; Topping, B. R.; Lynch, D. D.; Murphy, F.; Carter, J. L.; Lindenberg, M.

2007-12-01

Hypoxic, environmentally stressful conditions for endangered fish populations have been generated over the past century by an annual phytoplankton bloom in Upper Klamath Lake, OR. The bloom is consistently dominated by the nitrogen-fixing cyanophyte Aphanizomenon flos-aquae (AFA), thus a quantitative understanding of processes affecting the transport of biologically available phosphorus (P), presumably the limiting nutrient, is critical for resource management in the lake. This work was undertaken to help develop sound remediation or restoration strategies, and to set realistic expectations for water-quality improvements. Particle-reactive phosphate can adsorb or complex onto particles that settle and accumulate in the lake bed. Biogeochemical processes near the sediment-water interface can remobilize particle-bound P and generate a benthic flux of bioavailable P. This study provides estimates of the benthic flux of dissolved macronutrients (i.e., phosphorus and nitrogen species) before, during and after the period of: (1) increased water-column nutrient concentrations that cannot be accounted for by riverine inputs, and (2) the annual bloom of AFA. Benthic flux of dissolved orthophosphate was consistently positive (i.e., out of the sediment into the overlying water column) and ranged between 0.5 and 6.1 mg m-2 d-1. Assuming a lake area of 200 km2, this converts to a mass flux to the entire lake of 8,000 to 100,000 kg over a 3-month AFA bloom season which is comparable in magnitude to riverine inputs. An additional concern related to fish toxicity was that dissolved ammonium also displayed consistently positive benthic fluxes of 4 to 100 mg m-2 d-1; also comparable to riverine inputs. In contrast, dissolved nitrate exhibited a consistently negative flux (consumed by the sediment) with values ranging between -20 to -0.1 mg m-2 d-1. Macroinvertebrate densities of the order of 105 individuals-m-2 suggest that the diffusive-flux estimates may be significantly lower

In Situ Monitoring of Dispersion in the Water Column, Final Product for the Detection and Mitigation of Oil within the Water Column Project

DTIC Science & Technology

2018-01-31

properties in the presence of oil, such as conductivity, temperature , and turbidity (Battelle, 2014). The National Response Team (NRT) divides subsea...monitoring of oil and conditions (conductivity, temperature , salinity) in the water column, and discrete sampling and analysis (Battelle, 2014). Sensors

Water-Column Stratification Observed along an AUV-Tracked Isotherm

NASA Astrophysics Data System (ADS)

Zhang, Y.; Messié, M.; Ryan, J. P.; Kieft, B.; Stanway, M. J.; Hobson, B.; O'Reilly, T. C.; Raanan, B. Y.; Smith, J. M.; Chavez, F.

2016-02-01

Studies of marine physical, chemical and microbiological processes benefit from observing in a Lagrangian frame of reference, i.e. drifting with ambient water. Because these processes can be organized relative to specific density or temperature ranges, maintaining observing platforms within targeted environmental ranges is an important observing strategy. We have developed a novel method to enable a Tethys-class long-range autonomous underwater vehicle (AUV) (which has a propeller and a buoyancy engine) to track a target isotherm in buoyancy-controlled drift mode. In this mode, the vehicle shuts off its propeller and autonomously detects the isotherm and stays with it by actively controlling the vehicle's buoyancy. In the June 2015 CANON (Controlled, Agile, and Novel Observing Network) Experiment in Monterey Bay, California, AUV Makai tracked a target isotherm for 13 hours to study the coastal upwelling system. The tracked isotherm started from 33 m depth, shoaled to 10 m, and then deepened to 29 m. The thickness of the tracked isotherm layer (within 0.3°C error from the target temperature) increased over this duration, reflecting weakened stratification around the isotherm. During Makai's isotherm tracking, another long-range AUV, Daphne, acoustically tracked Makai on a circular yo-yo trajectory, measuring water-column profiles in Makai's vicinity. A wave glider also acoustically tracked Makai, providing sea surface measurements on the track. The presented method is a new approach for studying water-column stratification, but requires careful analysis of the temporal and spatial variations mingled in the vehicles' measurements. We will present a synthesis of the water column's stratification in relation to the upwelling conditions, based on the in situ measurements by the mobile platforms, as well as remote sensing and mooring data.

Removal of phosphorus from water by using volcanic ash soil (VAS): batch and column experiments.

PubMed

Nguyen, Huy Van; Maeda, Morihiro

2016-09-01

Using low-cost and naturally available materials is considered an optimal adsorbent for removing phosphorus (P) from water due to its simplicity and economic efficiency. This study examined the removal of P from water using volcanic ash soil (VAS) by batch and column experiments. The maximum adsorption capacity of P was 2.94 mg g -1 , estimated from the batch experiment according to a Langmuir isotherm. The column study showed a higher adsorption capacity of 5.57 mg g -1 . The breakthrough curve showed that influent water containing 2 mg L -1 P was completely purified by VAS within 1,230 pore volumes (PV). The breakthrough and saturation points of the curves were 3,100 PV and 14,875 PV, respectively. After an adsorption column was loaded with 20,508 PV, a regeneration procedure was developed to determine whether an ion exchange of P with chloride occurred or adsorbed P in the columns could be eluted. Approximately 20% of P was recovered from columns by desorption tests, regardless of NaCl solution or deionized water. Specific surface area and mineral concentrations are both important characteristics that improve the adsorption capacity of VAS. The present study suggests that VAS is a promising adsorbent to remove P in water.

Linking Water Table Dynamics to Carbon Cycling in Artificial Soil Column Incubations

NASA Astrophysics Data System (ADS)

Geertje, Pronk; Adrian, Mellage; Tatjana, Milojevic; Fereidoun, Rezanezhad; Cappellen Philippe, Van

2016-04-01

The biogeochemistry of wetlands soils is closely tied to their hydrology. Water table fluctuations that cause flooding and drying of these systems may lead to enhanced degradation of organic matter and release of greenhouse gasses (e.g. CO2, CH4) to the atmosphere. However, predicting the influence of water table fluctuations on the biogeochemical functioning of soils requires an understanding of the interactions of soil hydrology with biogeochemical and microbial processes. To determine the effects of water table dynamics on carbon cycling, we are carrying out state-of-the-art automated soil column experiments with fully integrated monitoring of hydro-bio-geophysical process variables under both constant and oscillating water table conditions. An artificial, homogeneous mixture consisting of minerals and organic matter is used to provide a well-defined starting material. The artificial soils are composed of quartz sand, montmorillonite, goethite and humus from a forested riparian zone, from which we also extracted the microbial inoculum added to the soil mixture. The artificial soils are packed into 60 cm high, 7.5 cm wide columns. In the currently ongoing experiment, three replicate columns are incubated while keeping the water table constant water at mid-depth, while another three columns alternate between drained and saturated conditions. Micro-sensors installed at different depths below the soil surface record time-series redox potentials (Eh) varying between oxidizing (~+700 mV) and reducing (~-200 mV) conditions. Continuous O2 levels throughout the soil columns are monitored using high-resolution, luminescence-based, Multi Fiber Optode (MuFO) microsensors. Pore waters are collected periodically with MicroRhizon samplers from different depths, and analyzed for pH, EC, dissolved inorganic and organic carbon and ion/cation compositions. These measurements allow us to track the changes in pore water geochemistry and relate them to differences in carbon cycling

Compact sieve-tray distillation column for ammonia-water absorption heat pump: Part 1 -- Design methodology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anand, G.; Erickson, D.C.

1999-07-01

The distillation column is a key component of ammonia-water absorption units including advanced generator-absorber heat exchange (GAX) cycle heat pumps. The design of the distillation column is critical to unit performance, size, and cost. The distillation column can be designed with random packing, structured packing, or various tray configurations. A sieve-tray distillation column is the least complicated tray design and is less costly than high-efficiency packing. Substantial literature is available on sieve tray design and performance. However, most of the correlations and design recommendations were developed for large industrial hydrocarbon systems and are generally not directly applicable to the compactmore » ammonia-water column discussed here. The correlations were reviewed and modified as appropriate for this application, and a sieve-tray design model was developed. This paper presents the sieve-tray design methodology for highly compact ammonia-water columns. A conceptual design of the distillation column for an 8 ton vapor exchange (VX) GAX heat pump is presented, illustrating relevant design parameters and trends. The design process revealed several issues that have to be investigated experimentally to design the final optimized rectifier. Validation of flooding and weeping limits and tray/point efficiencies are of primary importance.« less

Effect of water-column pH on sediment-phosphorus release rates in Upper Klamath Lake, Oregon, 2001

USGS Publications Warehouse

Fisher, Lawrence H.; Wood, Tamara M.

2004-01-01

Sediment-phosphorus release rates as a function of pH were determined in laboratory experiments for sediment and water samples collected from Shoalwater Bay in Upper Klamath Lake, Oregon, in 2001. Aerial release rates for a stable sediment/water interface that is representative of the sediment surface area to water column volume ratio (1:3) observed in the lake and volumetric release rates for resuspended sediment events were determined at three different pH values (8.1, 9.2, 10.2). Ambient water column pH (8.1) was maintained by sparging study columns with atmospheric air. Elevation of the water column pH to 9.2 was achieved through the removal of dissolved carbon dioxide by sparging with carbon dioxide-reduced air, partially simulating water chemistry changes that occur during algal photosynthesis. Further elevation of the pH to 10.2 was achieved by the addition of sodium hydroxide, which doubled average alkalinities in the study columns from about 1 to 2 milliequivalents per liter. Upper Klamath Lake sediments collected from the lake bottom and then placed in contact with lake water, either at a stable sediment/water interface or by resuspension, exhibited an initial capacity to take up soluble reactive phosphorus (SRP) from the water column rather than release phosphorus to the water column. At a higher pH this initial uptake of phosphorus is slowed, but not stopped. This initial phase was followed by a reversal in which the sediments began to release SRP back into the water column. The release rate of phosphorus 30 to 40 days after suspension of sediments in the columns was 0.5 mg/L/day (micrograms per liter per day) at pH 8, and 0.9 mg/L/day at pH 10, indicating that the higher pH increased the rate of phosphorus release by a factor of about two. The highest determined rate of release was approximately 10% (percent) of the rate required to explain the annual internal loading to Upper Klamath Lake from the sediments as calculated from a lake-wide mass balance

Seasonal Dynamics of Biogeochemical Processes in the Water Column of the Northeastern Black Sea

NASA Astrophysics Data System (ADS)

Rusanov, I. I.; Lein, A. Yu.; Makkaveev, P. N.; Klyuvitkin, A. A.; Kravchishina, M. D.; Ivanov, M. V.; Flint, M. V.

2018-01-01

Integrated studies on the hydrochemistry and water column rates of microbial processes in the eastern sector of the Black Sea along a standard 100-miles transect off Gelendzhik from the coast to the central part of the sea at water depths of 100-2170 m show that a series of warm winters and the absence of intense convective winter mixing resulted in a relatively low content of suspended particulate matter (SPM), particulate organic carbon (POC), and nutrients in the water column in March 2009. The relatively high SPM concentrations and the presence of isotopically light POC at the offshore station are indicative of the supply of terrigenous material from land and low contributions of phytoplanktonic organic matter to the composition of SPM. This may explain the low rates of biogeochemical processes in the water column near the coast. The surface layer at deep-water stations is dominated by isotopically heavy phytoplanktonic organic matter. This suggests that the supply of terrigenous material from land was insufficient in offshore deep-water areas. Therefore, warm winters and insufficient nutrient supply do not prevent photosynthesis in the photic layer of the deep-water zone, which generates organic substrates for heterotrophic aquatic communities. The results of isotopic analysis of POC, measurements of the rates biogeochemical processes, and the hydrochemical characteristics of the water column can be used to determine the nature and seasonal variability of the POC composition.

VIEW OF TWO HEAVY WATER STORAGE TANKS (BEHIND SUPPORT COLUMNS ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

VIEW OF TWO HEAVY WATER STORAGE TANKS (BEHIND SUPPORT COLUMNS AND STEEL BEAMS), SUB-BASEMENT LEVEL -27’, LOOKING SOUTHWEST - Physics Assembly Laboratory, Area A/M, Savannah River Site, Aiken, Aiken County, SC

Microbial methane production in oxygenated water column of an oligotrophic lake

PubMed Central

Grossart, Hans-Peter; Frindte, Katharina; Dziallas, Claudia; Eckert, Werner; Tang, Kam W.

2011-01-01

The prevailing paradigm in aquatic science is that microbial methanogenesis happens primarily in anoxic environments. Here, we used multiple complementary approaches to show that microbial methane production could and did occur in the well-oxygenated water column of an oligotrophic lake (Lake Stechlin, Germany). Oversaturation of methane was repeatedly recorded in the well-oxygenated upper 10 m of the water column, and the methane maxima coincided with oxygen oversaturation at 6 m. Laboratory incubations of unamended epilimnetic lake water and inoculations of photoautotrophs with a lake-enrichment culture both led to methane production even in the presence of oxygen, and the production was not affected by the addition of inorganic phosphate or methylated compounds. Methane production was also detected by in-lake incubations of lake water, and the highest production rate was 1.8–2.4 nM⋅h−1 at 6 m, which could explain 33–44% of the observed ambient methane accumulation in the same month. Temporal and spatial uncoupling between methanogenesis and methanotrophy was supported by field and laboratory measurements, which also helped explain the oversaturation of methane in the upper water column. Potentially methanogenic Archaea were detected in situ in the oxygenated, methane-rich epilimnion, and their attachment to photoautotrophs might allow for anaerobic growth and direct transfer of substrates for methane production. Specific PCR on mRNA of the methyl coenzyme M reductase A gene revealed active methanogenesis. Microbial methane production in oxygenated water represents a hitherto overlooked source of methane and can be important for carbon cycling in the aquatic environments and water to air methane flux. PMID:22089233

Slow Physics: Recording the Ascent and Descent of a Water Column

ERIC Educational Resources Information Center

Lindén, Johan; Källman, Kjell-Mikael; Holm, Erik

2018-01-01

A glass filled with carbon dioxide gas upside down on a plate of water constitutes an excellent demonstration of the solubility of gases. If the water level on the plate is maintained the CO[subscript 2] will slowly dissolve and the column of water will rise inside the glass, without quite reaching the ceiling, before an opposite process sets in:…

Bacterial production in the water column of small streams highly depends on terrestrial dissolved organic carbon

NASA Astrophysics Data System (ADS)

Graeber, Daniel; Poulsen, Jane R.; Rasmussen, Jes J.; Kronvang, Brian; Zak, Dominik; Kamjunke, Norbert

2016-04-01

In the recent years it has become clear that the largest part of the terrestrial dissolved organic carbon (DOC) pool is removed on the way from the land to the ocean. Yet it is still unclear, where in the freshwater systems terrestrial DOC is actually taken up, and for streams DOC uptake was assumed to happen mostly at the stream bottom (benthic zone). However, a recent monitoring study implies that water column but not benthic bacteria are strongly affected by the amount and composition of DOM entering streams from the terrestrial zone. We conducted an experiment to compare the reaction of the bacterial production and heterotrophic uptake in the water column and the benthic zone to a standardized source of terrestrial DOC (leaf leachate from Beech litter). In detail, we sampled gravel and water from eight streams with a gradient in stream size and land use. For each stream four different treatments were incubated at 16°C for three days and each stream: filtered stream water with gravel stones (representing benthic zone bacteria) or unfiltered stream water (representing water column bacteria), both either with (n = 5) or, without (n = 3) leaf leachate. We found that the bacterial uptake of leaf litter DOC was higher for the benthic zone likely due to the higher bacterial production compared to the water column. In contrast, the bacterial production per amount of leaf leachate DOC taken up was significantly higher for the bacteria in the water column than for those in the benthic zone. This clearly indicates a higher growth efficiency with the leaf leachate DOC for the bacteria in the water column than in the benthic zone. We found a high variability for the growth efficiency in the water column, which was best explained by a negative correlation of the DOC demand with stream width (R² = 0.86, linear correlation of log-transformed data). This was not the case for the benthic zone bacteria (R² = 0.02). This implies that water column bacteria in very small streams

Determination of water quality, toxicity and estrogenic activity in a nearshore marine environment in Rio de Janeiro, Southeastern Brazil.

PubMed

do Nascimento, Marilia Teresa Lima; Santos, Ana Dalva de Oliveira; Felix, Louise Cruz; Gomes, Giselle; de Oliveira E Sá, Mariana; da Cunha, Danieli Lima; Vieira, Natividade; Hauser-Davis, Rachel Ann; Baptista Neto, José Antonio; Bila, Daniele Maia

2018-03-01

Endocrine disrupting compounds (EDCs) can be found in domestic sewage, wastewater treatment plant effluents, natural water, rivers, lakes and in the marine environment. Jurujuba Sound, located in the state of Rio de Janeiro, Southeastern Brazil, receives untreated sewage into its waters, one the main sources of aquatic contamination in this area. In this context, the aim of the present study was to evaluate the estrogenic potential of water sampled from different depths and from areas with differential contamination levels throughout Jurujuba Sound. Water quality was evaluated and acute toxicity assays using Allviibrio fischeri were conducted, while estrogenic activity of the water samples was determined by a Yeast Estrogen Screening assay (YES). Water quality was mostly within the limits established for marine waters by the Brazilian legislation, with only DOC and ammoniacal nitrogen levels above the maximum permissible limits. No acute toxicity effects were observed in the Allivibrio fisheri assay. The YES assay detected moderate estrogenic activity in bottom water samples from 3 sampling stations, ranging from 0.5 to 3.2ngL -1 , as well as in one surface water sample. Estrogenic activity was most frequently observed in samples from the bottom of the water column, indicating adsorption of estrogenic compounds to the sediment. Copyright © 2017 Elsevier Inc. All rights reserved.

Mitigation of Oil in Water Column: Concept Development

DTIC Science & Technology

2016-06-01

Argonne National Laboratory (ANL) proposes to use polyurethane foam , a commonly used material for many general purposes, as the material of choice to...adsorb submerged oil. Prior to use, the foam undergoes a series of chemical processes in order to render it oleophilic and thus more susceptible to...17. Key Words Adsorbent Foam , Adhesion, Microbubble, Sinking Oil, Submerged Oil, Oil Mitigation, Sorbent, Water Column 18. Distribution Statement

Review of toxicity studies performed on an underground coal gasification condensate water

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barker, F.P.

1987-09-01

Three studies related to the toxicity of underground coal gasification (UCG) waters have bee conducted: (1) toxicity study of UCG water and its fractions as determined by the Microtox test, (2) toxicity study of biotreated UCG water as determined by the Microtox test, and (3) toxicity study of UCG water to macroinvertebrates. The results of these studies are summarized herein. The gas condensate water from the UCG process is extremely toxic as determined by assays with photoluminescent bacteria (Microtox), benthic (bottom-dwelling) macroinvertebrates (mayflies), and Daphnia magna (water flea). Microtox bioassays reveal that the toxic components of the water reside inmore » both the organophilic and hydrophilic fractions, although the organophilic fraction is notably more toxic. A sequential treatment process reduced the toxicity of the UCG water, as measured by the Microtox test. Solvent extraction (to remove phenols) followed by ammonia stripping yielded a less toxic water. Additional treatment by activated sludge further reduced toxicity. Finally, the addition of powdered activated carbon to the activated sludge yielded the least toxic water. A bioassay technique was developed for lotic (running water) macroinvertebrates (Drunella doddsi and Iron longimanus). The toxicity results were compared with results from the traditional test animal, Daphnia magna. Short-term exposures to the UCG waters were more toxic to Daphnia magna than to Drunella doddsi or Iron longimanus, although the toxicity values begin to merge with longer test exposure. The greater toxicity seems to be related to a thinner exoskeleton. 26 refs., 2 figs., 6 tabs.« less

Erratum to ;Coastal water column ammonium and nitrite oxidation are decoupled in summer;

NASA Astrophysics Data System (ADS)

Heiss, Elise M.; Fulweiler, Robinson W.

2017-07-01

Water column nitrification is a key process in the nitrogen cycle as it links reduced and oxidized forms of nitrogen and also provides the substrate (nitrate) needed for reactive nitrogen removal by denitrification. We measured potential water column ammonium and nitrite oxidation rates at four sites along an estuary to continental shelf gradient over two summers. In most cases, nitrite oxidation rates outpaced ammonium oxidation rates. Overall, ammonium and nitrite oxidation rates were higher outside of the estuary, and this trend was primarily driven by higher oxidation rates in deeper waters. Additionally, both ammonium and nitrite oxidation rates were impacted by different in situ variables. Ammonium oxidation rates throughout the water column as a whole were most positively correlated to depth and salinity and negatively correlated to dissolved oxygen, light, and temperature. In contrast, nitrite oxidation rates throughout the water column were negatively correlated with temperature, light and pH. Multivariate regression analysis revealed that surface (<20 m) ammonium oxidation rates were most strongly predicted by substrate (NH4+), salinity, and light, while deep (>20 m) rates were regulated by temperature, light, and [H+] (i.e. pH). In addition, surface (<20 m) nitrite oxidation rates were best explained by [H+] alone, while [H+], temperature, and dissolved oxygen all played a role in predicting deep (>20 m) nitrite oxidation rates. These results support the growing body of evidence that ammonium oxidation and nitrite oxidation are not always coupled, should be measured separately, and are influenced by different environmental conditions.

Fipronil mobility and transformation in undisturbed soil columns.

PubMed

Chatterjee, Niladri Sekhar; Gupta, Suman

2010-08-01

The downward movement of fipronil and its two toxic metabolites i.e. sulfone and desulfinyl were studied in undisturbed soil columns. Mobility behavior of two different formulations of fipronil viz granular and suspension concentrate were also studied. The undisturbed columns containing sandy loam soil were leached with water equivalent to 400 mm rainfall. Results revealed that although majority of the fipronil (approximately 80%) remained in top 0-5 cm layer, substantial amount (approximately 15%) moved to 5-10 cm depth. In case of metabolites sulfone and desulfinyl >90% of the residues remained in 0-5 cm core indicating low mobility of these metabolites in comparison to fipronil. Results of mobility behavior of fipronil in granular and SC formulations revealed low mobility in granular formulation. Sulfide was detected as the major degradation product in both the formulations and was found to be distributed throughout the column. A little amount of sulfone (0.1% of the total recovered) was also detected upto 10 cm depth.

Comparison of Passive Samplers for Monitoring Dissolved Organic Contaminants in Water Column Deployments

EPA Science Inventory

Nonionic organic contaminants (NOCs) are difficult to measure in the water column due to their inherent chemical properties resulting in low water solubility and high particle activity. Traditional sampling methods require large quantities of water to be extracted and interferen...

Evaluation of water treatment sludges toxicity using the Daphnia bioassay.

PubMed

Sotero-Santos, Rosana B; Rocha, Odete; Povinelli, Jurandyr

2005-10-01

Alum and ferric chloride sludges from two water treatment plants (WTPs) were analyzed regarding their physicochemical characteristics and toxicity to Daphnia similis. Experiments were carried out in the dry and rainy seasons. Acute and chronic toxicity was measured using survival and reproduction as measurement endpoints. No acute toxicity of the sludge was observed in 48 h exposure. Ferric chloride sludge caused chronic toxicity, demonstrated by low fecundity and some mortality, while alum sludge caused chronic toxicity characterized by low fecundity. Some sludge characteristics varied between samplings, including turbidity, solids contents, N, P and metal (Al and Fe) concentrations. These variables and the increase of chemical oxygen demand (COD) were identified as the main cause of degradation of the receiving waters. However, no relationship was observed between these variables and degree of toxicity. It is apparent from these results that water treatment sludges may be toxic and therefore may impair receiving waters. Alum sludge was less toxic than ferric chloride sludge.

Effects of water quality parameters on boron toxicity to Ceriodaphnia dubia.

PubMed

Dethloff, Gail M; Stubblefield, William A; Schlekat, Christian E

2009-07-01

The potential modifying effects of certain water quality parameters (e.g., hardness, alkalinity, pH) on the acute toxicity of boron were tested using a freshwater cladoceran, Ceriodaphnia dubia. By comparison, boron acute toxicity was less affected by water quality characteristics than some metals (e.g., copper and silver). Increases in alkalinity over the range tested did not alter toxicity. Increases in water hardness appeared to have an effect with very hard waters (>500 mg/L as CaCO(3)). Decreased pH had a limited influence on boron acute toxicity in laboratory waters. Increasing chloride concentration did not provide a protective effect. Boron acute toxicity was unaffected by sodium concentrations. Median acute lethal concentrations (LC(50)) in natural water samples collected from three field sites were all greater than in reconstituted laboratory waters that matched natural waters in all respects except for dissolved organic carbon. Water effect ratios in these waters ranged from 1.4 to 1.8. In subsequent studies using a commercially available source of natural organic matter, acute toxicity decreased with increased dissolved organic carbon, suggesting, along with the natural water studies, that dissolved organic carbon should be considered further as a modifier of boron toxicity in natural waters where it exceeds 2 mg/L.

Characteristic sediment and water column chlorophyll-a in the sea cucumber’s Paracaudina sp. habitat on the Kenjeran Water, Surabaya

NASA Astrophysics Data System (ADS)

Widianingsih, W.; Zaenuri, M.; Anggoro, S.; Kusumaningrum, H. P.; Hartati, R.

2018-03-01

The study of characteristic sediment and water column chlorophyll-a has an important role in the sea cucumber habitat. Sediment chlorophyll-a represents a productivity primer for the benthic community. This research has a purpose to investigate characteristic sediment and water column chlorophyll-a on the Kenjeran water, Surabaya. Sediment samples were collected by the ekman grab for analysis, grain size and nutrient. The sample for sediment chlorophyll-a was taken by core sampler. The water samples were taken with Nansen Bottles. According to the research result, the values of sediment chlorophyll-a at station 10, 11 and 12 were higher than the other stations. In contrast, the value of chlorophyll-a in the column water had almost the same value for each station. The sediment chlorophyll-a value on clay and silt sediment type was higher than the fine sand and coarse sediment type. The suitable habitat characteristic for Paracaudina sp. was clay and silt sediment with sediment chlorophyll concentration ranging from 347.82 mg·m-2 to 1135.52 mg·m-2.

Water column attenuation coefficient estimations in Alqueva reservoir

NASA Astrophysics Data System (ADS)

Potes, Miguel; João Costa, Maria; Salgado, Rui; Rodrigues, Gonçalo; Bortoli, Daniele

2017-04-01

The vertical structure of the underwater radiative absorption plays an important role in the thermal dynamics of the water surface layer and consequently on the energy budget at the water-lake interface. Thus, a better estimation of the irradiance at different levels is relevant to understand the lake-air interactions. The main purpose of this dataset of measurements is to estimate the spectral attenuation coefficient of the water column. The apparatus exploited in this work are composed of an optical cable linked to a portable FieldSpec UV/VNIR (ASD). This version has hemispherical field-of-view (FOV) of 180° allowing for measurements under all range of solar zenith. In situ water spectral reflectances were also obtained to help in the validation of satellite water leaving reflectances obtained from satellite spectroradiometers. It is intention of the team to develop an algorithm to derive the attenuation coefficient from satellite data in this reservoir.

Evaluating Rotavirus and Norovirus transport processes in standardised and natural soil-water columns experiments

NASA Astrophysics Data System (ADS)

Gamazo, Pablo; Schijven, Jack; Victoria, Matias; Alvareda, Elena; López Tort, Fernando; Ramos, Julián; Lizasoain, Andrés; Sapriza, Gonzalo; Castells, Matias; Colina, Rodney

2017-04-01

In Uruguay, as in many developed and developing countries, rotavirus and norovirus are major causes of diarrhea and others symptoms of acute gastroenteritis. In some areas of Uruguay, groundwater is the only source of water for human consumption. In the rural area of the Salto district, virus contamination has been detected in several groundwater wells. Because sewer coverage is low, the most probable sources of contamination are nearby septic systems. This work aims to evaluate the transport of rotavirus and norovirus from clinic samples in two sets of column experiments under saturated conditions: 6.7-cm columns with quartz sand (ionic strength 1mM, pH 7.0) and with sand from the Salto aquifer (Uruguay) (9,2% coarse sand, 47,8% medium sand, 40,5% fine sand, magnesium/calcium bicarbonate water, Ionic strength 15.1 mM, pH 7.2). Both viruses were seeded for 2 pore volumes onto the columns. Samples were collected at the column outlet and viruses were enumerated by Q-PRCR. Breakthrough curves were constructed and fitted to a two-site kinetic attachment/detachment model, including blocking using Hydrus-1D. In the quartz sand column, both rotavirus and norovirus were removed two orders in magnitude. In the Salto sand column, rotavirus was removed 2 log10 as well, but norovirus was removed 4 log10. The fitting of the breakthrough curves indicated that blocking played a role for rotavirus in the Salto sand column. These results are consistent with the field observation where only rotavirus was detected in the Salto aquifer, while similar concentrations in Salto sewer effluent were measured for both viruses. This work, besides reporting actual parameters values for human virus transport modelling, shows the significant differences in transport that human viruses can have in standardised and natural soil-water systems.

Semi-permeable surface analytical reversed-phase column for the improved trace analysis of acidic pesticides in water with coupled-column reversed-phase liquid chromatography with UV detection. Determination of bromoxynil and bentazone in surface water.

PubMed

Hogendoorn, E A; Westhuis, K; Dijkman, E; Heusinkveld, H A; den Boer, A C; Evers, E A; Baumann, R A

1999-10-08

The coupled-column (LC-LC) configuration consisting of a 3 microm C18 column (50 x 4.6 mm I.D.) as the first column and a 5 microm C18 semi-permeable-surface (SPS) column (150 x 4.6 mm I.D.) as the second column appeared to be successful for the screening of acidic pesticides in surface water samples. In comparison to LC-LC employing two C18 columns, the combination of C18/SPS-C18 significantly decreased the baseline deviation caused by the hump of the co-extracted humic substances when using UV detection (217 nm). The developed LC-LC procedure allowed the simultaneous determination of the target analytes bentazone and bromoxynil in uncleaned extracts of surface water samples to a level of 0.05 microg/l in less than 15 min. In combination with a simple solid-phase extraction step (200 ml of water on a 500 mg C18-bonded silica) the analytical procedure provides a high sample throughput. During a period of about five months more than 200 ditch-water samples originating from agricultural locations were analyzed with the developed procedure. Validation of the method was performed by randomly analyzing recoveries of water samples spiked at levels of 0.1 microg/l (n=10), 0.5 microg/l (n=7) and 2.5 microg/l (n=4). Weighted regression of the recovery data showed that the method provides overall recoveries of 95 and 100% for bentazone and bromoxynil, respectively, with corresponding intra-laboratory reproducibilities of 10 and 11%, respectively. Confirmation of the analytes in part of the samples extracts was carried out with GC-negative ion chemical ionization MS involving a derivatization step with bis(trifluoromethyl)benzyl bromide. No false negatives or positives were observed.

Bubble Shuttle: A newly discovered transport mechanism, which transfers microorganisms from the sediment into the water column

NASA Astrophysics Data System (ADS)

Schmale, O.; Stolle, C.; Leifer, I.; Schneider von Deimling, J.; Kiesslich, K.; Krause, S.; Frahm, A.; Treude, T.

2013-12-01

The diversity and abundance of methanotrophic microorganisms is well studied in the aquatic environment, indicating their importance in biogeochemical cycling of methane in the sediment and the water column. However, whether methanotrophs are distinct populations in these habitats or are exchanged between benthic and pelagic environments, remains an open question. Therefore, field studies were conducted at the 'Rostocker Seep' site (Coal Oil Point seep area, California, USA) to test our hypothesis that methane-oxidizing microorganisms can be transported by gas bubbles from the sediment into the water column. The natural methane emanating location 'Rostocker Seep' showed a strong surface water oversaturation in methane with respect to the atmospheric equilibrium. Catalyzed Reporter Deposition Fluorescence In Situ Hybridization (CARD-FISH) analyzes were performed to determine the abundance of aerobic and anaerobic methanotrophic microorganisms. Aerobic methane oxidizing bacteria were detected in the sediment and the water column, whereas anaerobic methanotrophs were detected exclusively in the sediment. The key device of the project was the newly developed "Bubble Catcher" used to collect naturally emanating gas bubbles at the sea floor together with particles attached to the bubble surface rim. Bubble Catcher experiments were carried out directly above a natural bubble release spot and on a reference site at which artificially released gas bubbles were caught, which had no contact with the sediment. CARD-FISH analyzes showed that aerobic methane oxidizing bacteria were transported by gas bubbles from the sediment into the water column. In contrast anaerobic methanotrophs were not detected in the bubble catcher. Further results indicate that this newly discovered Bubble Shuttle transport mechanism might influence the distribution pattern of methanotrophic microorganisms in the water column and even at the air-sea interface. Methane seep areas are often characterized

Bioswales reduce contaminants associated with toxicity in urban storm water.

PubMed

Anderson, Brian S; Phillips, Bryn M; Voorhees, Jennifer P; Siegler, Katie; Tjeerdema, Ronald

2016-12-01

Contamination and toxicity associated with urban storm water runoff are a growing concern because of the potential impacts on receiving systems. California water regulators are mandating implementation of green infrastructure as part of new urban development projects to treat storm water and increase infiltration. Parking lot bioswales are low impact development practices that promote filtering of runoff through plants and soil. Studies have demonstrated that bioswales reduce concentrations of suspended sediments, metals, and hydrocarbons. There have been no published studies evaluating how well these structures treat current-use pesticides, and studies have largely ignored whether bioswales reduce toxicity in surface water. Three storms were monitored at 3 commercial and residential sites, and reductions of contaminants and associated toxicity were quantified. Toxicity testing showed that the majority of untreated storm water samples were toxic to amphipods (Hyalella azteca) and midges (Chironomus dilutus), and toxicity was reduced by the bioswales. No samples were toxic to daphnids (Ceriodaphnia dubia) or fish (Pimephales promelas). Contaminants were significantly reduced by the bioswales, including suspended solids (81% reduction), metals (81% reduction), hydrocarbons (82% reduction), and pyrethroid pesticides (74% reduction). The single exception was the phenypyrazole pesticide fipronil, which showed inconsistent treatment. The results demonstrate these systems effectively treat contaminated storm water associated with surface water toxicity but suggest that modifications of their construction may be required to treat some contaminant classes. Environ Toxicol Chem 2016;35:3124-3134. © 2016 SETAC. © 2016 SETAC.

46 CFR 52.01-110 - Water-level indicators, water columns, gauge-glass connections, gauge cocks, and pressure gauges...

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 2 2014-10-01 2014-10-01 false Water-level indicators, water columns, gauge-glass connections, gauge cocks, and pressure gauges (modifies PG-60). 52.01-110 Section 52.01-110 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING POWER BOILERS General Requirements § 52.01-110 Water-level indicators, water...

46 CFR 52.01-110 - Water-level indicators, water columns, gauge-glass connections, gauge cocks, and pressure gauges...

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 2 2012-10-01 2012-10-01 false Water-level indicators, water columns, gauge-glass connections, gauge cocks, and pressure gauges (modifies PG-60). 52.01-110 Section 52.01-110 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING POWER BOILERS General Requirements § 52.01-110 Water-level indicators, water...

46 CFR 52.01-110 - Water-level indicators, water columns, gauge-glass connections, gauge cocks, and pressure gauges...

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Water-level indicators, water columns, gauge-glass connections, gauge cocks, and pressure gauges (modifies PG-60). 52.01-110 Section 52.01-110 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING POWER BOILERS General Requirements § 52.01-110 Water-level indicators, water...

46 CFR 52.01-110 - Water-level indicators, water columns, gauge-glass connections, gauge cocks, and pressure gauges...

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 2 2013-10-01 2013-10-01 false Water-level indicators, water columns, gauge-glass connections, gauge cocks, and pressure gauges (modifies PG-60). 52.01-110 Section 52.01-110 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING POWER BOILERS General Requirements § 52.01-110 Water-level indicators, water...

46 CFR 52.01-110 - Water-level indicators, water columns, gauge-glass connections, gauge cocks, and pressure gauges...

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 2 2011-10-01 2011-10-01 false Water-level indicators, water columns, gauge-glass connections, gauge cocks, and pressure gauges (modifies PG-60). 52.01-110 Section 52.01-110 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING POWER BOILERS General Requirements § 52.01-110 Water-level indicators, water...

Adsorption experiment of toxic micro-pollutants derived from automobiles using red soil.

PubMed

Kawai, Takahiro; Ichiki, Atsushi; Sawada, Yasunori

2015-01-01

In some countries, non-point source pollution derived from a city's economic activities tends to be a barrier to the improvement of water quality. Roadway runoff is known to contain toxic micro-pollutants such as polycyclic aromatic hydrocarbons (PAHs). Conversely, red soil is known to adsorb some organic matter. In this study, artificial roadway runoff water containing toxic micro-pollutants was made using roadway dust collected from a highway, and used for both batch-type tests and soil column tests with red soil in order to understand adsorption ability of the red soil on such toxic micro-pollutants, especially PAHs. In the batch-type tests, PAHs could be removed by approximately 40% when the contact time was 90 minutes. In the soil column tests, PAHs were removed by more than 80% while suspended solids were removed by more than 90%. Notably, PAHs with a high molecular weight were removed more readily in the tests than PAHs with a low molecular weight.

Modeling and Circumventing the Effect of Sediments and Water Column on Receiver Functions

NASA Astrophysics Data System (ADS)

Audet, P.

2017-12-01

Teleseismic P-wave receiver functions are routinely used to resolve crust and mantle structure in various geologic settings. Receiver functions are approximations to the Earth's Green's functions and are composed of various scattered phase arrivals, depending on the complexity of the underlying Earth structure. For simple structure, the dominant arrivals (converted and back-scattered P-to-S phases) are well separated in time and can be reliably used in estimating crustal velocity structure. In the presence of sedimentary layers, strong reverberations typically produce high-amplitude oscillations that contaminate the early part of the wave train and receiver functions can be difficult to interpret in terms of underlying structure. The effect of a water column also limits the interpretability of under-water receiver functions due to the additional acoustic wave propagating within the water column that can contaminate structural arrivals. We perform numerical modeling of teleseismic Green's functions and receiver functions using a reflectivity technique for a range of Earth models that include thin sedimentary layers and overlying water column. These modeling results indicate that, as expected, receiver functions are difficult to interpret in the presence of sediments, but the contaminating effect of the water column is dependent on the thickness of the water layer. To circumvent these effects and recover source-side structure, we propose using an approach based on transfer function modeling that bypasses receiver functions altogether and estimates crustal properties directly from the waveforms (Frederiksen and Delayney, 2015). Using this approach, reasonable assumptions about the properties of the sedimentary layer can be included in forward calculations of the Green's functions that are convolved with radial waveforms to predict vertical waveforms. Exploration of model space using Monte Carlo-style search and least-square waveform misfits can be performed to

Tidally driven water column hydro-geochemistry in a remediating acidic wetland

NASA Astrophysics Data System (ADS)

Johnston, Scott G.; Keene, Annabelle F.; Bush, Richard T.; Sullivan, Leigh A.; Wong, Vanessa N. L.

2011-10-01

SummaryManaged tidal inundation is a newly evolved technique for remediating coastal acid sulphate soil (CASS) wetlands. However, there remains considerable uncertainty regarding the hydro-geochemical pathways and spatiotemporal dynamics of residual H + and metal(loid) mobilisation into the tidal fringe surface waters of these uniquely iron-rich landscapes. Here, we examine the hydrology and water column chemistry across the intertidal slope of a remediating CASS wetland during several tide cycles. There was extreme spatial and temporal dynamism in water column chemistry, with pH fluctuating by ˜3 units (˜3.5-6.5) during a single tide cycle. Acute acidity was spatially confined to the upper intertidal slope, reflecting surface sediment properties, and tidal overtopping is an important pathway for mobilisation of residual H + and Al 3+ to the water column. Marine derived HCO3- was depleted from surface waters migrating across the intertidal slope and a strong gradient in HCO3- was observed from the tidal fringe to the adjacent tributary channel and nearby estuary. Tidal forcing generated oscillating hydraulic gradients in the shallow fringing aquifer, favouring ebb-tide seepage and driving rapid, heterogeneous advection of groundwater on the lower intertidal slope via surface connected macropores. A combination of diffusive and advective flux across the sediment-water interface led to persistent, elevated surface water Fe 2+ (˜10-1000 μM). The geochemical processes associated with Fe 2+ mobilisation displayed distinct spatial zonation, with low pH, proton-promoted desorption occurring on the upper intertidal slope, whilst circum-neutral pH, Fe(III)-reducing processes dominated the lower intertidal slope. Arsenic was also mobilised into surface waters on the lower intertidal slope under moderate pH (˜6.0) conditions and was strongly positively correlated with Fe 2+. Saturation index values for aragonite were substantially depressed (-1 to -5) and significantly

History of water-column anoxia in the Black Sea indicated by pyrite framboid size distributions

USGS Publications Warehouse

Wilkin, R.T.; Arthur, M.A.; Dean, W.E.

1997-01-01

A detailed study of size distributions of framboidal pyrite in Holocene Black Sea sediments establishes the timing of a change from deposition under an oxic water column to deposition under an anoxic and sulfidic water column. In the most recent carbonate-rich sediments (Unit I) and in the organic carbon-rich sapropel (Unit II), framboid size distributions are remarkably uniform (mean diameter= 5 ??m); over 95% of the framboids in Unit I and Unit II are < 7 ??m in diameter. These properties of framboidal pyrite are consistent with framboid nucleation and growth within an anoxic and sulfidic water column, followed by transport to the sediment-water interface, cessation of pyrite growth due to the exhaustion of reactive iron, and subsequent burial. In contrast, the organic carbon-poor sediments of lacustrine Unit III contain pyrite framboids that are generally much larger in size (mean diameter = 10 ??m). In Unit III, over 95% of the framboids are < 25 ??m in diameter, 40% of framboids are between 7 ??m and 25 ??m, and framboids up to 50 ??m in diameter are present. This distribution of sizes suggests framboid nucleation and growth within anoxic sediment porewaters. These new data on size distributions of framboidal pyrite confirm that the development of water-column anoxia in the Black Sea coincided with the initiation of deposition of laminated Unit II sapropels.

Column leaching and sorption experiments to assess the mobility of potentially toxic elements in industrially contaminated land.

PubMed

Anderson, P; Davidson, C M; Duncan, A L; Littlejohn, D; Ure, A M; Garden, L M

2000-06-01

Made-up ground collected from layers of a trial pit excavated on a former industrial site was treated with artificial rainwater in a series of column leaching and sorption experiments. Metal mobility and the ability of various layers of material obtained from the pit to act as sources or sinks of potentially toxic elements were assessed. Samples from different layers varied in their abilities to raise the pH of rainwater applied at pH 3.5 and 4.3, and this was reflected in the amounts of metals mobilised by the rainwater as it percolated through the soil column. Material from the top two layers of the pit released cadmium, copper, manganese, lead, nickel and zinc to the aqueous phase, but the lower layers, with higher buffering capacity, were able to resist acidification even when the equivalent of 12 months' rainfall (western UK) was applied. Column sorption experiments confirmed the ability of material from layer 4 (48-50 cm) to take up copper, manganese and zinc. Metals were determined in the leachates by flame and electrothermal atomic absorption spectrometry and principle anions by ion chromatography.

Formation of well-mixed warm water column in central Bohai Sea during summer: Role of high-frequency atmospheric forcing

NASA Astrophysics Data System (ADS)

Ma, Weiwei; Wan, Xiuquan; Wang, Zhankun; Liu, Yulong; Wan, Kai

2017-12-01

The influence of high-frequency atmospheric forcing on the formation of a well-mixed summer warm water column in the central Bohai Sea is investigated comparing model simulations driven by daily surface forcing and those using monthly forcing data. In the absence of high-frequency atmospheric forcing, numerical simulations have repeatedly failed to reproduce this vertically uniform column of warm water measured over the past 35 years. However, high-frequency surface forcing is found to strongly influence the structure and distribution of the well-mixed warm water column, and simulations are in good agreement with observations. Results show that high frequency forcing enhances vertical mixing over the central bank, intensifies downward heat transport, and homogenizes the water column to form the Bohai central warm column. Evidence presented shows that high frequency forcing plays a dominant role in the formation of the well-mixed warm water column in summer, even without the effects of tidal and surface wave mixing. The present study thus provides a practical and rational way of further improving the performance of oceanic simulations in the Bohai Sea and can be used to adjust parameterization schemes of ocean models.

Removal of toxic metals and nonmetals from contaminated water.

PubMed

Bartzatt, R; Cano, M; Johnson, L; Nagel, D

1992-04-01

The effects of the application of potassium ferrate to remove possible toxic compounds are presented. Potassium ferrate (K2FeO4) is shown in this work to be an effective means to remove toxic metals and nonmetals from aqueous solution. The toxic material present in water is precipitated from aqueous solution and readily removed. Potassium ferrate removes itself from solution. Discolored contaminated water may be made clear by utilizing potassium ferrate. In addition, turbidities of solutions induced by dissolved substances are eliminated by the action of potassium ferrate. The efficacy of potassium ferrate in cleaning contaminated water shows great potential in application to municipal and industrial waste water.

Carbon and oxygen dynamics on the Louisiana continental shelf: role of water column primary production and respiration

EPA Science Inventory

We conducted a multi-year study of the Louisiana continental shelf (LCS) to better understand the linkages between water column net metabolism and the formation of hypoxia (dissolved oxygen <2 ml O2 L-1) in the region. Rates of water column community respiration (R) and primary p...

Column displacement experiments to evaluate electrical conductivity effects on electromagnetic soil water sensing

USDA-ARS?s Scientific Manuscript database

Bulk electrical conductivity (EC) in superactive soils has been shown to strongly influence electromagnetic sensing of permittivity. However, these effects are dependent on soil water content and temperature as well as the pore water conductivity. We carried out isothermal column displacement experi...

Deflection of natural oil droplets through the water column in deep-water environments: The case of the Lower Congo Basin

NASA Astrophysics Data System (ADS)

Jatiault, Romain; Dhont, Damien; Loncke, Lies; de Madron, Xavier Durrieu; Dubucq, Dominique; Channelliere, Claire; Bourrin, François

2018-06-01

Numerous recurrent seep sites were identified in the deep-water environment of the Lower Congo Basin from the analysis of an extensive dataset of satellite-based synthetic-aperture radar images. The integration of current data was used to link natural oil slicks with active seep-related seafloor features. Acoustic Doppler current profiler measurements across the water column provided an efficient means to evaluate the horizontal deflection of oil droplets rising through the water column. Eulerian propagation model based on a range of potential ascension velocities helped to approximate the path for rising oil plume through the water column using two complementary methods. The first method consisted in simulating the reversed trajectory of oil droplets between sea-surface oil slick locations observed during current measurements and seep-related seafloor features while considering a range of ascension velocities. The second method compared the spatial spreading of natural oil slicks from 21 years of satellite monitoring observations for water depths ranging from 1200 to 2700 m against the modeled deflections during the current measurement period. The mapped oil slick origins are restricted to a 2.5 km radius circle from associated seep-related seafloor features. The two methods converge towards a range of ascension velocities for oil droplets through the water column, estimated between 3 and 8 cm s-1. The low deflection values validate that the sub-vertical projection of the average surface area of oil slicks at the sea surface can be used to identify the origin of expelled hydrocarbon from the seafloor, which expresses as specific seafloor disturbances (i.e. pockmarks or mounds) known to expel fluids.

Carbon isotope dynamics in the water column and surface sediments of marginal seas

NASA Astrophysics Data System (ADS)

Lipka, Marko; Liu, Bo; Schmiedinger, Iris; Böttcher, Michael E.

2017-04-01

The microbial mineralization of organic matter in marine sediments leads to the accumulation of dissolved inorganic carbon (DIC) and other metabolites into the interstitial waters. Pore water profiles sensitively reflect the zones of dominant biogeochemical processes, net trans-formation rates, and diffusive and advective transport of dissolved species across the sediment-water interface. They are controlled by different factors like sedimentology, bottom water currents and redox conditions, microbial activity, and the availability of electron acceptors/donors. The biogeochemical processes create steep gradients in DIC and its carbon isotope composition. One boundary condition for transport processes in the sediment is defined by the composition of the water column, which is under impact by physical mixing processes (e.g., salinity gradient; sediment-water exchange), biological activity and carbon dioxide exchange at the water-atmosphere interface. We present here the results of detailed biogeochemical investigations of vertical water column and pore water profiles from two brackish marginal seas: the Baltic Sea and the Black Sea. The water column on a transect between the North Sea and the southern Baltic Sea as well within the Black Sea were investigated on three cruises with RV MS Merian (MSM33, MSM50, MSM51). In addition, biogeochemical processes and associated element fluxes across the sediment-water interface were studied in key regions of Baltic Sea and Black Sea using pore water and sediment samples retrieved from sediment cores that were collected with a multi-coring device. Water samples were analyzed for metals, nutrients, and metabolites concentrations as well as stable carbon isotope composition of DIC to allow a modeling of steady-state transformation, volumetric transformation rates and element fluxes. The isotope composition of the dissolved inorganic carbon system shows a gradient between the North and the Baltic Sea, following the salinity during

Intensification of ammonia removal from waste water in biologically active zeolitic ion exchange columns.

PubMed

Almutairi, Azel; Weatherley, Laurence R

2015-09-01

The use of nitrification filters for the removal of ammonium ion from waste-water is an established technology deployed extensively in municipal water treatment, in industrial water treatment and in applications such as fish farming. The process involves the development of immobilized bacterial films on a solid packing support, which is designed to provide a suitable host for the film, and allow supply of oxygen to promote aerobic action. Removal of ammonia and nitrite is increasingly necessary to meet drinking water and discharge standards being applied in the US, Europe and other places. Ion-exchange techniques are also effective for removal of ammonia (as the ammonium ion) from waste water and have the advantage of fast start-up times compared to biological filtration which in some cases may take several weeks to be fully operational. Here we explore the performance of ion exchange columns in which nitrifying bacteria are cultivated, with the goal of a "combined" process involving simultaneous ion-exchange and nitrification, intensified by in-situ aeration with a novel membrane module. There were three experimental goals. Firstly, ion exchange zeolites were characterized and prepared for comparative column breakthrough studies for ammonia removal. Secondly effective in-situ aeration for promotion of nitrifying bacterial growth was studied using a number of different membranes including polyethersulfone (PES), polypropylene (PP), nylon, and polytetra-fluoroethylene (PTFE). Thirdly the breakthrough performance of ion exchange columns filled with zeolite in the presence of aeration and in the presence of nitrifying bacteria was determined to establish the influence of biomass, and aeration upon breakthrough during ammonium ion uptake. The methodology adopted included screening of two types of the naturally occuring zeolite clinoptilolite for effective ammonia removal in continuous ion-exchange columns. Next, the performance of fixed beds of clinoptilolite in the

Gas Chromatograph Method Optimization Trade Study for RESOLVE: 20-meter Column v. 8-meter Column

NASA Technical Reports Server (NTRS)

Huz, Kateryna

2014-01-01

RESOLVE is the payload on a Class D mission, Resource Prospector, which will prospect for water and other volatile resources at a lunar pole. The RESOLVE payload's primary scientific purpose includes determining the presence of water on the moon in the lunar regolith. In order to detect the water, a gas chromatograph (GC) will be used in conjunction with a mass spectrometer (MS). The goal of the experiment was to compare two GC column lengths and recommend which would be best for RESOLVE's purposes. Throughout the experiment, an Inficon Fusion GC and an Inficon Micro GC 3000 were used. The Fusion had a 20m long column with 0.25mm internal diameter (Id). The Micro GC 3000 had an 8m long column with a 0.32mm Id. By varying the column temperature and column pressure while holding all other parameters constant, the ideal conditions for testing with each column length in their individual instrument configurations were determined. The criteria used for determining the optimal method parameters included (in no particular order) (1) quickest run time, (2) peak sharpness, and (3) peak separation. After testing numerous combinations of temperature and pressure, the parameters for each column length that resulted in the most optimal data given my three criteria were selected. The ideal temperature and pressure for the 20m column were 95 C and 50psig. At this temperature and pressure, the peaks were separated and the retention times were shorter compared to other combinations. The Inficon Micro GC 3000 operated better at lower temperature mainly due to the shorter 8m column. The optimal column temperature and pressure were 70 C and 30psig. The Inficon Micro GC 3000 8m column had worse separation than the Inficon Fusion 20m column, but was able to separate water within a shorter run time. Therefore, the most significant tradeoff between the two column lengths was peak separation of the sample versus run time. After performing several tests, it was concluded that better

Increasing global accessibility and understanding of water column sonar data

NASA Astrophysics Data System (ADS)

Wall, C.; Anderson, C.; Mesick, S.; Parsons, A. R.; Boyer, T.; McLean, S. J.

2016-02-01

Active acoustic (sonar) technology is of increasing importance for research examining the water column. NOAA uses water column sonar data to map acoustic properties from the ocean surface to the seafloor - from bubbles to biology to bottom. Scientific echosounders aboard fishery survey vessels are used to estimate biomass, measure fish school morphology, and characterize habitat. These surveys produce large volumes of data that are costly and difficult to maintain due to their size, complexity, and proprietary format that require specific software and extensive knowledge. However, through proper management they can deliver valuable information beyond their original collection purpose. In order to maximize the benefit to the public, the data must be easily discoverable and accessible. Access to ancillary data is also needed for complete environmental context and ecosystem assessment. NOAA's National Centers for Environmental Information, in partnership with NOAA's National Marine Fisheries Service and the University of Colorado, created a national archive for the stewardship and distribution of water column sonar data collected on NOAA and academic vessels. A web-based access page allows users to query the metadata and access the raw sonar data. Visualization products being developed allow researchers and the public to understand the quality and content of large volumes of archived data more easily. Such products transform the complex data into a digestible image or graphic and are highly valuable for a broad audience of varying backgrounds. Concurrently collected oceanographic data and bathymetric data are being integrated into the data access web page to provide an ecosystem-wide understanding of the area ensonified. Benefits of the archive include global access to an unprecedented nationwide dataset and the increased potential for researchers to address cross-cutting scientific questions to advance the field of marine ecosystem acoustics.

Oscillating water column structural model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Copeland, Guild; Bull, Diana L; Jepsen, Richard Alan

2014-09-01

An oscillating water column (OWC) wave energy converter is a structure with an opening to the ocean below the free surface, i.e. a structure with a moonpool. Two structural models for a non-axisymmetric terminator design OWC, the Backward Bent Duct Buoy (BBDB) are discussed in this report. The results of this structural model design study are intended to inform experiments and modeling underway in support of the U.S. Department of Energy (DOE) initiated Reference Model Project (RMP). A detailed design developed by Re Vision Consulting used stiffeners and girders to stabilize the structure against the hydrostatic loads experienced by amore » BBDB device. Additional support plates were added to this structure to account for loads arising from the mooring line attachment points. A simplified structure was designed in a modular fashion. This simplified design allows easy alterations to the buoyancy chambers and uncomplicated analysis of resulting changes in buoyancy.« less

Continuous-flow leaching in a rotating coiled column for studies on the mobility of toxic elements in dust samples collected near a metallurgic plant.

PubMed

Fedotov, Petr S; Ermolin, Mikhail S; Ivaneev, Alexandr I; Fedyunina, Natalia N; Karandashev, Vasily K; Tatsy, Yury G

2016-03-01

Continuous-flow (dynamic) leaching in a rotating coiled column has been applied to studies on the mobility of Zn, Cd, Cu, Pb, Ni, Sb, As, S, and other potentially toxic elements in atmospherically deposited dust samples collected near a large copper smelter (Chelyabinsk region, Russia). Water and simulated "acid rain" (pH 4) were used as eluents. The technique enables not only the fast and efficient leaching of elements but as well time-resolved studies on the mobilization of heavy metals, sulphur, and arsenic in environmentally relevant forms to be made. It is shown that up to 1.5, 4.1, 1.9, 11.1, and 46.1% of Pb, As, Cu, Zn, and S, correspondingly, can be easily mobilized by water. Taking into consideration that the total concentrations of these elements in the samples under investigation are surprisingly high and vary in the range from 2.7 g/kg (for arsenic) to 15.5 g/kg (for sulphur), the environmental impact of the dust may be dramatic. The simulated acid rain results in somewhat higher recoveries of elements, except Cu and Pb. The proposed approach and the data obtained can very useful for the risk assessment related to the mobility of potentially toxic elements and their inclusion in the biogeochemical cycle. Copyright © 2015 Elsevier Ltd. All rights reserved.

Benthic flux of dissolved nickel into the water column of south San Francisco Bay

USGS Publications Warehouse

Topping, B.R.; Kuwabara, J.S.; Parcheso, Francis; Hager, S.W.; Arnsberg, A.J.; Murphy, Fred

2001-01-01

Field and laboratory studies were conducted between April, 1998 and May, 1999 to provide the first direct measurements of the benthic flux of dissolved (0.2-micron filtered) nickel between the bottom sediment and water column at three sites in the southern component of San Francisco Bay (South Bay), California. Dissolved nickel and predominant ligands (represented by dissolved organic carbon, and sulfides) were the solutes of primary interest, although a variety of ancillary measurements were also performed to provide a framework for interpretation. Results described herein integrate information needs identified by the State Water Resources Control Board and local stakeholders with fundamental research associated with the U.S. Geological Survey Toxic Substances Hydrology Program. Dissolved-Ni concentrations in the bottom water over the three sampling dates ranged from 34 to 43 nanomoles per liter. Dissolved-macronutrient concentrations in the bottom water were consistently higher (frequently by orders of magnitude) than surface-water determinations reported for similar times and locations (Regional Monitoring Program, 2001). This is consistent with measured positive benthic fluxes for the macronutrients. Benthic-flux estimates for dissolved nickel from core-incubations, when areally averaged over the South Bay, were significant (that is, of equivalent or greater order of magnitude) relative to previously reported freshwater point and non-point sources. This observation is consistent with previous determinations for other metals, and with the potential remobilization of sediment-associated metals that have been ubiquitously distributed in the South Bay. Similar to dissolved-nickel results, benthic flux of macronutrients was also consistently significant relative to surface-water inputs. These results add to a growing body of knowledge that strongly suggests a need to consider contaminant transport across the sediment-water interface when establishing future

Physicochemical and biological factors controlling water column metabolism in Sundarbans estuary, India

PubMed Central

2012-01-01

Background Sundarbans is the single largest deltaic mangrove forest in the world, formed at estuarine phase of the Ganges - Brahmaputra river system. Primary productivity of marine and coastal phytoplankton contributes to 15% of global oceanic production. But unfortunately estuarine dynamics of tropical and subtropical estuaries have not yet received proper attention in spite of the fact that they experience considerable anthropogenic interventions and a baseline data is required for any future comparison. This study is an endeavor to this end to estimate the primary productivity (gross and net), community respiration and nitrification rates in different rivers and tidal creeks around Jharkhali island, a part of Sundarbans estuary surrounded by the mangrove forest during a period of three years starting from November’08 to October’11. Results Various physical and chemical parameters of water column like pH, temperature, conductivity, dissolved oxygen, turbidity, suspended particulate matter, secchi disc index, tidal fluctuation and tidal current velocity, standing crop and nutrients were measured along with water column productivity. Relationship of net water column productivity with algal biomass (standing crop), nutrient loading and turbidity were determined experimentally. Correlations of bacterial abundance with community respiration and nitrification rates were also explored. Annual integrated phytoplankton production rate of this tidal estuary was estimated to be 151.07 gC m-2 y-1. Gross primary productivity showed marked inter annual variation being lowest in monsoon and highest in postmonsoon period. Conclusion Average primary production was a function of nutrient loading and light penetration in the water column. High aquatic turbidity, conductivity and suspended particulate matter were the limiting factors to attenuate light penetration with negative influence on primary production. Community respiration and nitrification rates of the estuary were

Physicochemical and biological factors controlling water column metabolism in Sundarbans estuary, India.

PubMed

Chaudhuri, Kaberi; Manna, Suman; Sarma, Kakoli Sen; Naskar, Pankaj; Bhattacharyya, Somenath; Bhattacharyya, Maitree

2012-10-19

Sundarbans is the single largest deltaic mangrove forest in the world, formed at estuarine phase of the Ganges - Brahmaputra river system. Primary productivity of marine and coastal phytoplankton contributes to 15% of global oceanic production. But unfortunately estuarine dynamics of tropical and subtropical estuaries have not yet received proper attention in spite of the fact that they experience considerable anthropogenic interventions and a baseline data is required for any future comparison. This study is an endeavor to this end to estimate the primary productivity (gross and net), community respiration and nitrification rates in different rivers and tidal creeks around Jharkhali island, a part of Sundarbans estuary surrounded by the mangrove forest during a period of three years starting from November'08 to October'11. Various physical and chemical parameters of water column like pH, temperature, conductivity, dissolved oxygen, turbidity, suspended particulate matter, secchi disc index, tidal fluctuation and tidal current velocity, standing crop and nutrients were measured along with water column productivity. Relationship of net water column productivity with algal biomass (standing crop), nutrient loading and turbidity were determined experimentally. Correlations of bacterial abundance with community respiration and nitrification rates were also explored. Annual integrated phytoplankton production rate of this tidal estuary was estimated to be 151.07 gC m-2 y-1. Gross primary productivity showed marked inter annual variation being lowest in monsoon and highest in postmonsoon period. Average primary production was a function of nutrient loading and light penetration in the water column. High aquatic turbidity, conductivity and suspended particulate matter were the limiting factors to attenuate light penetration with negative influence on primary production. Community respiration and nitrification rates of the estuary were influenced by the bacterial abundance

Transfer of gold nanoparticles from the water column to the estuarine food web

NASA Astrophysics Data System (ADS)

Ferry, John L.; Craig, Preston; Hexel, Cole; Sisco, Patrick; Frey, Rebecca; Pennington, Paul L.; Fulton, Michael H.; Scott, I. Geoff; Decho, Alan W.; Kashiwada, Shosaku; Murphy, Catherine J.; Shaw, Timothy J.

2009-07-01

Within the next five years the manufacture of large quantities of nanomaterials may lead to unintended contamination of terrestrial and aquatic ecosystems. The unique physical, chemical and electronic properties of nanomaterials allow new modes of interaction with environmental systems that can have unexpected impacts. Here, we show that gold nanorods can readily pass from the water column to the marine food web in three laboratory-constructed estuarine mesocosms containing sea water, sediment, sea grass, microbes, biofilms, snails, clams, shrimp and fish. A single dose of gold nanorods (65 nm length × 15 nm diameter) was added to each mesocosm and their distribution in the aqueous and sediment phases monitored over 12 days. Nanorods partitioned between biofilms, sediments, plants, animals and sea water with a recovery of 84.4%. Clams and biofilms accumulated the most nanoparticles on a per mass basis, suggesting that gold nanorods can readily pass from the water column to the marine food web.

Technical Note: Detection of gas bubble leakage via correlation of water column multibeam images

NASA Astrophysics Data System (ADS)

Schneider von Deimling, J.; Papenberg, C.

2011-07-01

Hydroacoustic detection of natural gas release from the seafloor has been conducted in the past by using singlebeam echosounders. In contrast modern multibeam swath mapping systems allow much wider coverage, higher resolution, and offer 3-D spatial correlation. However, up to the present, the extremely high data rate hampers water column backscatter investigations. More sophisticated visualization and processing techniques for water column backscatter analysis are still under development. We here present such water column backscattering data gathered with a 50 kHz prototype multibeam system. Water column backscattering data is presented in videoframes grabbed over 75 s and a "re-sorted" singlebeam presentation. Thus individual gas bubbles rising from the 24 m deep seafloor clearly emerge in the acoustic images and rise velocities can be determined. A sophisticated processing scheme is introduced to identify those rising gas bubbles in the hydroacoustic data. It applies a cross-correlation technique similar to that used in Particle Imaging Velocimetry (PIV) to the acoustic backscatter images. Tempo-spatial drift patterns of the bubbles are assessed and match very well measured and theoretical rise patterns. The application of this processing scheme to our field data gives impressive results with respect to unambiguous bubble detection and remote bubble rise velocimetry. The method can identify and exclude the main driver for misinterpretations, i.e. fish-mediated echoes. Even though image-based cross-correlation techniques are well known in the field of fluid mechanics for high resolution and non-inversive current flow field analysis, this technique was never applied in the proposed sense for an acoustic bubble detector.

Anthropogenic microlitter in the Baltic Sea water column.

PubMed

Bagaev, Andrei; Khatmullina, Liliya; Chubarenko, Irina

2018-04-01

Microlitter (0.5-5mm) concentrations in water column (depth range from 0 to 217.5m) of the main Baltic Proper basins are reported. In total, 95 water samples collected in 6 research cruises in 2015-2016 in the Bornholm, Gdansk, and Gotland basins were analysed. Water from 10- and 30-litre Niskin bathometers was filtered through the 174μm filters, and the filtrate was examined under optical microscope (40×). The bulk mean concentration was 0.40±0.58 items per litre, with fibres making 77% of them. Other types of particles are the paint flakes (19%) and fragments (4%); no microbeads or pellets. The highest concentrations are found in the near-bottom samples from the coastal zone (2.2-2.7 items per litre max) and from near-surface waters (0.5m) in the Bornholm basin (5 samples, 1.6-2.5 items per litre). Distribution of particles over depths, types, and geographical regions is presented. Copyright © 2017 Elsevier Ltd. All rights reserved.

Assessment of pathogen levels in stream water column and bed sediment of Merced River Watershed in California

NASA Astrophysics Data System (ADS)

Vaddella, V. K.; Pandey, P.; Biswas, S.; Lewis, D. J.

2014-12-01

Mitigating pathogen levels in surface water is crucial for protecting public health. According to the U.S. Environmental Protection Agency (US EPA), approximately 480,000 km of rivers/streams are contaminated in the U.S., and a major cause of contamination is elevated levels of pathogen/pathogen indicator. Many of past studies showed considerably higher pathogen levels in sediment bed than that of the stream water column in rivers. In order to improve the understanding of pathogen levels in rivers in California, we carried out an extensive pathogen monitoring study in four different watersheds (Bear Creek, Ingalsbe, Maxwell, and Yosemite watersheds) of Merced River. Stream water and streambed sediment samples were collected from 17 locations. Pathogen levels (E. coli O157:H7, Salmonella spp., and Listeria monocytogenes) were enumerated in streambed sediment and water column. In addition, the impacts of heat stress on pathogen survival were assessed by inoculating pathogens into the water and sediment samples for understanding the pathogen survival in stream water column and streambed sediment. The pathogen enumeration (in water column and sediment bed) results indicated that the E. coli O157:H7, Salmonella spp. and Listeria monocytogenes levels were non-detectable in the water column and streambed sediment. The results of heat stress (50◦ C for 180 minutes) test indicated a pathogen decay at one order of magnitude (108 cfu/ml to 107 cfu/ml). Nonetheless, higher pathogen levels (1.13 × 107 cfu/ml) after the heat stress study showed potential pathogen survival at higher temperature. Preliminary results of this study would help in understanding the impacts of elevated temperature on pathogen in stream environment. Further studies are required to test the long-term heat-stress impacts on pathogen survival.

Diverse Water-Magma Interactions In The Conduit And Column During The 2008 Okmok Eruption, Alaska

NASA Astrophysics Data System (ADS)

Ort, M. H.; Unema, J. A.; Neal, C. A.; Larsen, J. F.; Schaefer, J. R.

2015-12-01

Ground, surface, and atmospheric water affected the Okmok (central Aleutians, Alaska) 2008 eruption in diverse ways. An initial 16-km-high column produced a widespread coarse fallout. Explosion breccias and lithic-rich fallout overlie this deposit proximally, topped by an ash with abundant accretionary lapilli and ash pellets. After this, a water-rich flood, likely from ejected lake water, left deposits in the eastern caldera. Pyroclastic density currents traveled northward in the caldera, leaving both coarse-ash dune forms and massive unsorted deposits. We interpret these to mark vent opening or widening, with diverse currents forming in different sectors due to directed explosions and partial column collapse. The rest of the eruption was characterized by water-rich ash and steam columns 1-4 km high, with brief <9-km-high periods. Several vents formed during the eruption; one enlarged a pre-existing lake and others formed a new lake, a small tuff ring, and a 300-m-high tuff cone. Surface water, shallow groundwater in coarse sediments, and atmospheric water were abundantly available throughout the eruption. Cone D Lake (13.6 Mm3 volume) drained into the North vent 7-10 days into the eruption, with massive groundwater and sediment removal. Nearby pit craters have no ejecta; surficial lava collapsed when underlying sediments were removed. The eruption column was typically gray or white, rarely black, and ashfall dominates the deposits at all localities, reflecting efficient fragmentation and deposition. Scrubbing of the plume by erupted and atmospheric water caused rapid deposition of the ash, so deposits thin rapidly away from the vent. Laminae and thin lenses dominate the deposits outside the caldera whereas some intracaldera deposits are massive beds up to several decimeters thick. Wind-blown ash-laden mist made low-angle ripples and discontinuous laminae; ash rain deposited continuous laminae. A capping vesicular ash (Av soil horizon) formed as a water

Trends of total water vapor column above the Arctic from satellites observations

NASA Astrophysics Data System (ADS)

Alraddawi, Dunya; Sarkissian, Alain; Keckhut, Philippe; Bock, Olivier; Claud, Chantal; Irbah, Abdenour

2016-04-01

Atmospheric water vapor (H2O) is the most important natural (as opposed to man-made) greenhouse gas, accounting for about two-thirds of the natural greenhouse effect. Despite this importance, its role in climate and its reaction to climate change are still difficult to assess. Many details of the hydrological cycle are poorly understood, such as the process of cloud formation and the transport and release of latent heat contained in the water vapor. In contrast to other important greenhouse gases like carbon dioxide (CO2) and methane, water vapor has a much higher temporal and spatial variability. Total precipitable water (TPW) or the total column of water vapor (TCWV) is the amount of liquid water that would result if all the water vapor in the atmospheric column of unit area were condensed. TCWV distribution contains valuable information on the vigor of the hydrological processes and moisture transport in the atmosphere. Measurement of TPW can be obtained based on atmospheric water vapor absorption or emission of radiation in the spectral range from UV to MW. TRENDS were found over the terrestrial Arctic by means of TCWV retrievals (using Moderate Resolution Imaging Spectro-radiometer (MODIS) near-infrared (2001-2015) records). More detailed approach was made for comparisons with ground based instruments over Sodankyla - Finland (TCWV from: SCIAMACHY 2003-2011, GOME-2A 2007-2011, SAOZ 2003-2011, GPS 2003-2011, MODIS 2003-2011)

Haloactamides versus halomethanes formation and toxicity in chloraminated drinking water.

PubMed

Yang, Fan; Zhang, Jing; Chu, Wenhai; Yin, Daqiang; Templeton, Michael R

2014-06-15

In this study we quantified the concentrations of nine haloacetamides (HAcAms) and nine halomethanes (HMs) in the final waters of five drinking water treatment plants (DWTPs) that use either chlorination or chloramination for disinfection and evaluated the toxicity of dichloroacetamide (DCAcAm) and dichloromethane (DCM) in normal rat kidney (NRK) cells using four in vitro toxicity assays. All the DWTPs final waters contained primarily di-HAcAms, followed by tri- and mono-HAcAms, and DCAcAm was the most abundant species of the 9 HAcAms, regardless of chlorination or chloramination being applied. In the final waters of DWTPs using chlorination, tri-HMs (trihalomethanes, THMs) accounted for the majority of HMs, whereas chloramination resulted in more di-HMs (especially DCM) than THMs. All four in vitro toxicity assays indicated that the NRK cell chronic cytotoxicity and acute genotoxicity of DCAcAm were substantially higher than that of DCM. In view of observed occurrence concentrations and quantified toxicity levels, the findings of this study suggest that DCAcAm represents a higher toxicity risk than DCM in chloraminated drinking waters. Copyright © 2014 Elsevier B.V. All rights reserved.

Diversity of active aerobic methanotrophs along depth profiles of arctic and subarctic lake water column and sediments

PubMed Central

He, Ruo; Wooller, Matthew J; Pohlman, John W; Quensen, John; Tiedje, James M; Leigh, Mary Beth

2012-01-01

Methane (CH4) emitted from high-latitude lakes accounts for 2–6% of the global atmospheric CH4 budget. Methanotrophs in lake sediments and water columns mitigate the amount of CH4 that enters the atmosphere, yet their identity and activity in arctic and subarctic lakes are poorly understood. We used stable isotope probing (SIP), quantitative PCR (Q-PCR), pyrosequencing and enrichment cultures to determine the identity and diversity of active aerobic methanotrophs in the water columns and sediments (0–25 cm) from an arctic tundra lake (Lake Qalluuraq) on the north slope of Alaska and a subarctic taiga lake (Lake Killarney) in Alaska's interior. The water column CH4 oxidation potential for these shallow (∼2 m deep) lakes was greatest in hypoxic bottom water from the subarctic lake. The type II methanotroph, Methylocystis, was prevalent in enrichment cultures of planktonic methanotrophs from the water columns. In the sediments, type I methanotrophs (Methylobacter, Methylosoma and Methylomonas) at the sediment-water interface (0–1 cm) were most active in assimilating CH4, whereas the type I methanotroph Methylobacter and/or type II methanotroph Methylocystis contributed substantially to carbon acquisition in the deeper (15–20 cm) sediments. In addition to methanotrophs, an unexpectedly high abundance of methylotrophs also actively utilized CH4-derived carbon. This study provides new insight into the identity and activity of methanotrophs in the sediments and water from high-latitude lakes. PMID:22592821

Diversity of active aerobic methanotrophs along depth profiles of arctic and subarctic lake water column and sediments

USGS Publications Warehouse

He, Ruo; Wooller, Matthew J.; Pohlman, John W.; Quensen, John; Tiedje, James M.; Leigh, Mary Beth

2012-01-01

Methane (CH4) emitted from high-latitude lakes accounts for 2–6% of the global atmospheric CH4 budget. Methanotrophs in lake sediments and water columns mitigate the amount of CH4 that enters the atmosphere, yet their identity and activity in arctic and subarctic lakes are poorly understood. We used stable isotope probing (SIP), quantitative PCR (Q-PCR), pyrosequencing and enrichment cultures to determine the identity and diversity of active aerobic methanotrophs in the water columns and sediments (0–25 cm) from an arctic tundra lake (Lake Qalluuraq) on the north slope of Alaska and a subarctic taiga lake (Lake Killarney) in Alaska's interior. The water column CH4 oxidation potential for these shallow (~2m deep) lakes was greatest in hypoxic bottom water from the subarctic lake. The type II methanotroph, Methylocystis, was prevalent in enrichment cultures of planktonic methanotrophs from the water columns. In the sediments, type I methanotrophs (Methylobacter, Methylosoma and Methylomonas) at the sediment-water interface (0–1 cm) were most active in assimilating CH4, whereas the type I methanotroph Methylobacter and/or type II methanotroph Methylocystis contributed substantially to carbon acquisition in the deeper (15–20 cm) sediments. In addition to methanotrophs, an unexpectedly high abundance of methylotrophs also actively utilized CH4-derived carbon. This study provides new insight into the identity and activity of methanotrophs in the sediments and water from high-latitude lakes.

Tidal variability of CO2 and CH4 emissions from the water column within a Rhizophora mangrove forest (New Caledonia).

PubMed

Jacotot, Adrien; Marchand, Cyril; Allenbach, Michel

2018-08-01

We performed a preliminary study to quantify CO 2 and CH 4 emissions from the water column within a Rhizophora spp. mangrove forest. Mean CO 2 and CH 4 emissions during the studied period were 3.35±3.62mmolCm -2 h -1 and 18.30±27.72μmolCm -2 h -1 , respectively. CO 2 and CH 4 emissions were highly variable and mainly driven by tides (flow/ebb, water column thickness, neap/spring). Indeed, an inverse relationship between the magnitude of the emissions and the thickness of the water column above the mangrove soil was observed. δ 13 CO 2 values ranged from -26.88‰ to -8.6‰, suggesting a mixing between CO 2 -enriched pore waters and lagoon incoming waters. In addition, CO 2 and CH 4 emissions were significantly higher during ebb tides, mainly due to the progressive enrichment of the water column by diffusive fluxes as its residence time over the forest floor increased. Eventually, we observed higher CO 2 and CH 4 emissions during spring tides than during neap tides, combined to depleted δ 13 CO 2 values, suggesting a higher contribution of soil-produced gases to the emissions. These higher emissions may result from higher renewable of the electron acceptor and enhanced exchange surface between the soil and the water column. This study shows that CO 2 and CH 4 emissions from the water column were not negligible and must be considered in future carbon budgets in mangroves. Copyright © 2018 Elsevier B.V. All rights reserved.

Chlorophyll-a thin layers in the Magellan fjord system: The role of the water column stratification

NASA Astrophysics Data System (ADS)

Ríos, Francisco; Kilian, Rolf; Mutschke, Erika

2016-08-01

Fjord systems represent hotspots of primary productivity and organic carbon burial. However, the factors which control the primary production in mid-latitude fjords are poorly understood. In this context, results from the first fine-scale measurements of bio-oceanographic features in the water column of fjords associated with the Strait of Magellan are presented. A submersible fluorescence probe (FP) was used to measure the Chlorophyll-a (Chl-a) concentration in situ, along with conductivity, temperature, hydrostatic pressure (depth) and dissolved oxygen (CTD-O2) of the water column. The Austral spring results of 14 FP-CTD-O2 profiles were used to define the vertical and horizontal patches of the fluorescent pigment distribution and their spatial relations with respect to the observed hydrographic features. Three zones with distinct water structures were defined. In all zones, the 'brown' spectral group (diatoms and dinoflagellates) predominated accounting for >80 wt% of the phytoplankton community. Thin layers with high Chl-a concentration were detected in 50% of the profiles. These layers harbored a substantial amount (30-65 wt%) of the phytoplankton biomass. Stratification was positively correlated to the occurrence of Chl-a thin layers. In stable and highly stratified water columns the integrated Chl-a concentration was higher and frequently located within thin layers whereas well mixed water columns displayed lower values and more homogeneous vertical distribution of Chl-a. These results indicate that mixing/stability processes are important factors accounting to the vertical distribution of Chl-a in Magellan fjords.

Bioluminescent bioreporter pad biosensor for monitoring water toxicity.

PubMed

Axelrod, Tim; Eltzov, Evgeni; Marks, Robert S

2016-01-01

Toxicants in water sources are of concern. We developed a tool that is affordable and easy-to-use for monitoring toxicity in water. It is a biosensor composed of disposable bioreporter pads (calcium alginate matrix with immobilized bacteria) and a non-disposable CMOS photodetector. Various parameters to enhance the sensor's signal have been tested, including the effect of alginate and bacterium concentrations. The effect of various toxicants, as well as, environmental samples were tested by evaluating their effect on bacterial luminescence. This is the first step in the creation of a sensitive and simple operative tool that may be used in different environments. Copyright © 2015 Elsevier B.V. All rights reserved.

Tropical intercontinental optical measurement network of aerosol, precipitable water and total column ozone

NASA Technical Reports Server (NTRS)

Holben, B. N.; Tanre, D.; Reagan, J. A.; Eck, T. F.; Setzer, A.; Kaufman, Y. A.; Vermote, E.; Vassiliou, G. D.; Lavenu, F.

1992-01-01

A new generation of automatic sunphotometers is used to systematically monitor clear sky total column aerosol concentration and optical properties, precipitable water and total column ozone diurnally and annually in West Africa and South America. The instruments are designed to measure direct beam sun, solar aureole and sky radiances in nine narrow spectral bands from the UV to the near infrared on an hourly basis. The instrumentation and the algorithms required to reduce the data for subsequent analysis are described.

Cell culture-based biosensing techniques for detecting toxicity in water.

PubMed

Tan, Lu; Schirmer, Kristin

2017-06-01

The significant increase of contaminants entering fresh water bodies calls for the development of rapid and reliable methods to monitor the aquatic environment and to detect water toxicity. Cell culture-based biosensing techniques utilise the overall cytotoxic response to external stimuli, mediated by a transduced signal, to specify the toxicity of aqueous samples. These biosensing techniques can effectively indicate water toxicity for human safety and aquatic organism health. In this review we account for the recent developments of the mainstream cell culture-based biosensing techniques for water quality evaluation, discuss their key features, potentials and limitations, and outline the future prospects of their development. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Impact of the temporal variation of oxygen contents in the water column on the biogeochemistry of the benthic zone

NASA Astrophysics Data System (ADS)

Rigaud, Sylvain; Deflandre, Bruno; Grenz, Christian; Pozzato, Lara; Cesbron, Florian; Meulé, Samuel; Bonin, Patricia; Michotey, Valérie; Mirleau, Pascal; Mirleau, Fatma; Knoery, Joel; Zuberer, Frédéric; Guillemain, Dorian; Marguerite, Sébatien; Mayot, Nicolas; Faure, Vincent; Grisel, Raphael; Radakovitch, Olivier

2017-04-01

The desoxygenation of the water column in coastal areas, refered as coastal hypoxia, is currently a growing phenomenon still particularly complex to predict. This is mainly due to the fact that the biogeochemical response of the benthic ecosystem to the variation of the oxygen contents in the water column remains poorly understood. Dissolved oxygen concentration is a key parameter controling the benthic micro- and macro-community as well as the biogeochemical reactions occuring in the surface sediment. More particularly, the variation over variable time scales (from hour to years) of the oxygen deficit may induce different pathways for biogeochemical processes such as the oxydation of freshly deposited organic matter and nutrients and metals recycling. This results in variable chemical fluxes at the sediment-water interface, that may in turn, support the eutrophication and desoxygenation of the aquatic system. Our study focus on the Berre lagoon, an eutrophicated mediterranean lagoon impacted by hypoxia events in the water column. Three stations, closely located but impacted by contrasted temporal variation of oxygen deficit in the water column were selected: one station with rare oxygen deficit and with functionnal macrofauna community, one station with almost permanent oxygen deficit and no macrofauna community and one intermediate station with seasonnal oxygen deficit and degraded macrofauna community. Each station was surveyed once during a same field survey while the intermediate station was surveyed seasonnaly. For each campaign, we report vertical profiles of the main chemical components (oxygen, nutrients, metals) along the water-column/sediment continuum, with an increased vertical resolution in the benthic zone using a multi-tool approach (high vertical resolution suprabenthic water sampler and microsensors profiler). In addition, total chemical fluxes at the sediment-water interface was obtained using benthic chambers. This dataset was used to evaluate

Water column and bed-sediment core samples collected from Brownlee Reservoir near Oxbow, Oregon, 2012

USGS Publications Warehouse

Fosness, Ryan L.; Naymik, Jesse; Hopkins, Candice B.; DeWild, John F.

2013-01-01

The U.S. Geological Survey, in cooperation with Idaho Power Company, collected water-column and bed-sediment core samples from eight sites in Brownlee Reservoir near Oxbow, Oregon, during May 5–7, 2012. Water-column and bed-sediment core samples were collected at each of the eight sites and analyzed for total mercury and methylmercury. Additional bed-sediment core samples, collected from three of the eight sites, were analyzed for pesticides and other organic compounds, trace metals, and physical characteristics, such as particle size. Total mercury and methylmercury were detected in each of the water column and bed-sediment core samples. Only 17 of the 417 unique pesticide and organic compounds were detected in bed-sediment core samples. Concentrations of most organic wastewater compounds detected in bed sediment were less than the reporting level. Trace metals detected were greater than the reporting level in all the bed-sediment core samples submitted for analysis. The particle size distribution of bed-sediment core samples was predominantly clay mixed with silt.

A toxicity-based method for evaluating safety of reclaimed water for environmental reuses.

PubMed

Xu, Jianying; Zhao, Chuntao; Wei, Dongbin; Du, Yuguo

2014-10-01

A large quantity of toxic chemical pollutants possibly remains in reclaimed water due to the limited removal efficiency in traditional reclamation processes. It is not enough to guarantee the safety of reclaimed water using conventional water quality criteria. An integrated assessment method based on toxicity test is necessary to vividly depict the safety of reclaimed water for reuse. A toxicity test battery consisting of lethality, genotoxicity and endocrine disrupting effect was designed to screen the multiple biological effects of residual toxic chemicals in reclaimed water. The toxicity results of reclaimed water were converted into the equivalent concentrations of the corresponding positive reference substances (EQC). Simultaneously, the predicted no-effect concentration (PNEC) of each positive reference substance was obtained by analyzing the species sensitivity distribution (SSD) of toxicity data. An index "toxicity score" was proposed and valued as 1, 2, 3, or 4 depending on the ratio of the corresponding EQC to PNEC. For vividly ranking the safety of reclaimed water, an integrated assessment index "toxicity rank" was proposed, which was classified into A, B, C, or D rank with A being the safest. The proposed method was proved to be effective in evaluating reclaimed water samples in case studies. Copyright © 2014. Published by Elsevier B.V.

Wind driven vertical transport in a vegetated, wetland water column with air-water gas exchange

NASA Astrophysics Data System (ADS)

Poindexter, C.; Variano, E. A.

2010-12-01

gas transfer coefficient, k, for both a vegetated condition and a control condition (no cylinders). The presence of cylinders in the tank substantially increased the rate of the gas transfer. For the highest wind speed, the gas transfer coefficient was several times higher when cylinders were present compared to when they were not. The gas transfer coefficient for the vegetated condition also proved sensitive to wind speed, increasing markedly with increasing mean wind speeds. Profiles of dissolved oxygen revealed well-mixed conditions in the bulk water column following prolonged air-flow above the water surface, suggesting application of the thin-film model is appropriate. The enhanced gas exchange observed might be explained by increased turbulent kinetic energy within the water column and the anisotropy of the cylinder array, which constrains horizontal motions more than vertical motions. Improved understanding of gas exchange in vegetated water columns may be of particularly use to investigations of carbon fluxes and soil accretion in wetlands. Reference: Nepf, H. (1999), Drag, turbulence, and diffusion in flow through emergent vegetation, Water Resour. Res., 35(2), 479-489.

Assessment of microplastic toxicity to embryonic development of the sea urchin Lytechinus variegatus (Echinodermata: Echinoidea).

PubMed

Nobre, C R; Santana, M F M; Maluf, A; Cortez, F S; Cesar, A; Pereira, C D S; Turra, A

2015-03-15

Apart from the physiological impacts on marine organisms caused by ingesting microplastics, the toxicity caused by substances leaching from these particles into the environment requires investigation. To understand this potential risk, we evaluated the toxicity of virgin (raw) and beach-stranded plastic pellets to the development of embryos of Lytechinus variegatus, simulating transfers of chemical compounds to interstitial water and water column by assays of pellet-water interface and elutriate, respectively. Both assays showed that virgin pellets had toxic effects, increasing anomalous embryonic development by 58.1% and 66.5%, respectively. The toxicity of stranded pellets was lower than virgin pellets, and was observed only for pellet-water interface assay. These results show that (i) plastic pellets act as a vector of pollutants, especially for plastic additives found on virgin particles; and that (ii) the toxicity of leached chemicals from pellets depends on the exposure pathway and on the environmental compartment in which pellets accumulate. Copyright © 2015 Elsevier Ltd. All rights reserved.

Removal of dissolved organic carbon by aquifer material: Correlations between column parameters, sorption isotherms and octanol-water partition coefficient.

PubMed

Pradhan, Snigdhendubala; Boernick, Hilmar; Kumar, Pradeep; Mehrotra, Indu

2016-07-15

The correlation between octanol-water partition coefficient (KOW) and the transport of aqueous samples containing single organic compound is well documented. The concept of the KOW of river water containing the mixture of organics was evolved by Pradhan et al. (2015). The present study aims at determining the KOW and sorption parameters of synthetic aqueous samples and river water to finding out the correlation, if any. The laboratory scale columns packed with aquifer materials were fed with synthetic and river water samples. Under the operating conditions, the compounds in the samples did not separate, and all the samples that contain more than one organic compound yielded a single breakthrough curve. Breakthrough curves simulated from sorption isotherms were compared with those from the column runs. The sorption parameters such as retardation factor (Rf), height of mass transfer zone (HMTZ), rate of mass transfer zone (RMTZ), breakpoint column capacity (qb) and maximum column capacity (qx) estimated from column runs, sorption isotherms and models developed by Yoon-Nelson, Bohart-Adam and Thomas were in agreement. The empirical correlations were found between the KOW and sorption parameters. The transport of the organics measured as dissolved organic carbon (DOC) through the aquifer can be predicted from the KOW of the river water and other water samples. The novelty of the study is to measure KOW and to envisage the fate of the DOC of the river water, particularly during riverbank filtration. Statistical analysis of the results revealed a fair agreement between the observed and computed values. Copyright © 2016 Elsevier Ltd. All rights reserved.

Comparison of Passive Samplers for Monitoring Dissolved Organic Contaminants in Water Column Deployments NAC/SETAC 2012

EPA Science Inventory

Nonionic organic contaminants (NOCs) are difficult to measure in the water column due to their inherent chemical properties resulting in low water solubility and high particle activity. Traditional sampling methods require large quantities of water to be extracted and interferen...

Fixed bed column study for Cu (II) removal from aqueous solution using water hyacinth (Eichornia crassipes) biomass.

PubMed

Gandhimathi, R; Ramesh, S T; Yadu, Anubhav; Bharathi, K S

2013-07-01

This paper reports the results of the study on the performance of low-cost biosorbent water hyacinth (WH) in removing Cu (II) from aqueous solution. The adsorbent material adopted was found to be an efficient media for the removal of Cu (II) in continuous mode using fixed bed column. The column studies were conducted with 10 mg/L metal solution with a flow rate of 10 mL/min with different bed depths such as 10, 20 and 30 cm. The column design parameters like adsorption rate constant, adsorption capacity and minimum bed depth were calculated. It was found that, the adsorption capacity of copper ions by water hyacinth increased by increasing the bed depth and the contact time.

Water column 230Th systematics in the eastern equatorial Pacific Ocean and implications for sediment focusing

NASA Astrophysics Data System (ADS)

Singh, Ajay K.; Marcantonio, Franco; Lyle, Mitchell

2013-01-01

In an effort to investigate the cause of higher-than-expected sediment inventories of 230Th in the Panama Basin, thorium isotopes were measured in eight deep-water casts within the Guatemala, Panama, and Peru Basins along a meridional transect at ˜86°W between 6.5°N and 8.5°S. Dissolved 230Th concentrations increase linearly from the surface to 1000 m at each transect station. Below 1000 m, the deep waters of the Panama Basin show the highest deficit (˜50%) of 230Th assuming a reversible exchange of 230Th between dissolved and sinking particulate matter, and in comparison with the globally averaged water-column 230Th. Peru Basin waters have a larger range of dissolved 230Th concentrations (7.9-16.5 fg/kg) than that within Panama Basin waters (5.7-7.1 fg/kg). There is a progressive decrease in average dissolved deep-water (>1000 m) 230Th concentrations from the southernmost sites in the Peru Basin toward the Panama Basin. We suggest that intense scavenging by upwelling-derived-productivity near the equator (±2°) and resuspension of ubiquitous Mn-rich particulates in Panama Basin sediments are the primary causes of the significant south-to-north lateral gradient in deep-water dissolved 230Th. Although 230Th from Peru Basin waters may be transported and then scavenged and ultimately buried in the Panama Basin, our calculations suggest that the quantity of advected 230Th is relatively small (between 15% and 30% of the total 230Th being produced within water column of the Panama Basin itself). Panama Basin sediment focusing factors greater than 1.3 cannot be explained by lateral export and excess scavenging of water column 230Th. Dissolved 232Th concentrations, in addition to being the lowest reported so far in the literature, fall within a very narrow range (6-26 pg/kg), and are generally invariable with depth. This invariability suggests the dissolution of dust in surface waters as a likely sole source of dissolved 232Th for the entire water column.

Distinct Iron-binding Ligands in the Upper Water Column at Station ALOHA

NASA Astrophysics Data System (ADS)

Bundy, R.; Boiteau, R.; Repeta, D.

2016-02-01

The distribution and chemical properties of iron-binding organic ligands at station ALOHA were examined using a combination of solid phase extraction (SPE) followed by high pressure liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICPMS). HPLC-ICPMS ligand measurements were complemented by competitive ligand exchange adsorptive cathodic stripping voltammetry (CLE-ACSV) analysis using salicylaldoxime as the added ligand. By HPLC-ICPMS, we find enhanced concentrations of distinct naturally-occurring polar iron-binding ligands present at the surface and in the chlorophyll maximum. Lower concentrations were found in the subsurface, where a suite of non-polar ligands was detected. Siderophores were present at the deepest depths sampled at station ALOHA, down to 400m. Incubation studies provided evidence for the production of iron-binding ligands associated with nutrient amended phytoplankton growth in surface waters, and as a result of microbial particle remineralization in the subsurface water column. Ligands classes identified via SPE were then compared to CLE-ACSV ligand measurements, as well as the conditional stability constants measured from model polar and non-polar siderophores, yielding insight to the sources of iron-binding ligands throughout the water column at station ALOHA.

Distinct Aeromonas Populations in Water Column and Associated with Copepods from Estuarine Environment (Seine, France)

PubMed Central

Chaix, Gautier; Roger, Frédéric; Berthe, Thierry; Lamy, Brigitte; Jumas-Bilak, Estelle; Lafite, Robert; Forget-Leray, Joëlle; Petit, Fabienne

2017-01-01

Aeromonas spp. are ubiquitous bacteria primarily recovered from aquatic ecosystems. They are found in fresh water as well as estuarine and marine waters, and in association with numerous autochthonous aquatic organisms in these environments. However, aeromonads are also etiologic agents of fish diseases and are now recognized as emerging pathogens in humans. The estuary is therefore a key environment, harboring autochthonous aeromonads, and aeromonads originating from humans and animals, mainly released by treated WWTP effluent or watershed run-off via tributaries. The present study compares the abundance and the diversity of Aeromonas populations. Over 2 years of monitoring (eight campaigns from February 2013 to November 2015), the occurrence of Aeromonas was investigated within the water column (water and fluid mud) and in association with copepods. Moreover, the diversity of Aeromonas populations was ascertained by analyzing gyrB and radA sequences, and the antibiotic-resistance phenotypes were determined using the disk diffusion method. This study shows, for the first time, the presence of Aeromonas spp. in water (1.1 × 102 to 1.2 ± 0.3 × 103 CFU.100 mL-1), fluid mud (2.6 ± 2.6 × 102 to 9.8 ± 0.9 × 103 CFU.g-1) and in association with living copepods (1.9 ± 0.7 × 102 to >1.1 × 104 CFU.g-1) in the Seine estuary. Moreover, the diversity study, conducted on 36 strains isolated from the water column and 47 strains isolated from copepods, indicates distinct populations within these two compartments. Strains distributed in five clusters corresponding to A. bestiarum (n = 6; 5.45%), A. encheleia (n = 1; 0.91%), A. media (n = 22; 20.0%), A. rivipollensis (n = 34; 30.91%) and A. salmonicida (n = 47; 42.73%). A. salmonicida is the most abundant species associated with Eurytemora affinis (n = 35; 74.47%). In contrast, A. salmonicida accounts for only 30.56% (n = 11) of isolates in the water column. This study shows the coexistence of distinct populations of

Arctic Marine Water Isotope Characteristics: In-situ, Continuous Surface and Water Column Isoscapes (δ18O and δ2H) and Linkages into the Marine Food Web

NASA Astrophysics Data System (ADS)

Welker, J. M.; Klein, E. S.; Collins, E.; Iken, K.; Hopcroft, R. R.; Norcross, B.

2016-12-01

The Arctic is under going rapid and profound sea ice, temperature, food web, ocean current, precipitation and synoptic weather changes. Delineating these changes requires a suite of tools, especially those that have the ability to depict the interactive nature of the marine system. Understanding the marine water isotope cycle is paramount to recognizing the unique isotopic properties of this region and to characterize possibly the reorganization of the Arctic. The Arctic marine water isotope system has been primarily examined with shore-based stations and or episodic station sampling; without continuous surface water sampling in combination with station-specific water column and organismic measurements. New technologies that allow in situ and continuous water isotope measurements (vapor and liquid) and the integration of inorganic and organic water isotope geochemistry provide a means to reveal in more detail the fundamental traits of the Arctic marine water isotope system. In July and August of 2016, we are measuring seawater surface (8 m depth) isotopes (δ18O and δ2H) in-situ and continuously (Picarro CWS system) along a research transect (60oN to 77oN) from the Gulf of Alaska to the Arctic Ocean Basin. These continuous surface water isotope measurements are being combined with periodic water column isotope profiling and corresponding organic δ18O and δ2H measurements of pelagic and benthic organisms (microbes to fish) to depths of up to 2600m. We measured surface seawater δ18O that from -1‰ to -6‰; while seawater profiles followed vertical separation in the water column; possibly reflecting divergent currents of the Arctic. Station based δ18O and δ2H values of surface water did not vary by more than 1‰ δ18O over the course of our 24-36 hour sampling periods. The δ18O and δ2H values of marine organism throughout the water column and by trophic level will be analyzed and a seawater-food web model will be developed in addition to surface and water

Modulation of oxygen production in Archaean oceans by episodes of Fe(II) toxicity

NASA Astrophysics Data System (ADS)

Swanner, Elizabeth D.; Mloszewska, Aleksandra M.; Cirpka, Olaf A.; Schoenberg, Ronny; Konhauser, Kurt O.; Kappler, Andreas

2015-02-01

Oxygen accumulated in the surface waters of the Earth's oceans and atmosphere several hundred million years before the Great Oxidation Event between 2.4 and 2.3 billion years ago. Before the Great Oxidation Event, periods of enhanced submarine volcanism associated with mantle plume events supplied Fe(II) to sea water. These periods generally coincide with the disappearance of indicators of the presence of molecular oxygen in Archaean sedimentary records. The presence of Fe(II) in the water column can lead to oxidative stress in some organisms as a result of reactions between Fe(II) and oxygen that produce reactive oxygen species. Here we test the hypothesis that the upwelling of Fe(II)-rich, anoxic water into the photic zone during the late Archaean subjected oxygenic phototrophic bacteria to Fe(II) toxicity. In laboratory experiments, we found that supplying Fe(II) to the anoxic growth medium housing a common species of planktonic cyanobacteria decreased both the efficiency of oxygenic photosynthesis and their growth rates. We suggest that this occurs because of increasing intracellular concentrations of reactive oxygen species. We use geochemical modelling to show that Fe(II) toxicity in conditions found in the late Archaean photic zone could have substantially inhibited water column oxygen production, thus decreasing fluxes of oxygen to the atmosphere. We therefore propose that the timing of atmospheric oxygenation was controlled by the timing of submarine, plume-type volcanism, with Fe(II) toxicity as the modulating factor.

Tracking pyrethroid toxicity in surface water samples: Exposure dynamics and toxicity identification tools for laboratory tests with Hyalella azteca (Amphipoda).

PubMed

Deanovic, Linda A; Stillway, Marie; Hammock, Bruce G; Fong, Stephanie; Werner, Inge

2018-02-01

Pyrethroid insecticides are commonly used in pest control and are present at toxic concentrations in surface waters of agricultural and urban areas worldwide. Monitoring is challenging as a result of their high hydrophobicity and low toxicity thresholds, which often fall below the analytical methods detection limits (MDLs). Standard daphnid bioassays used in surface water monitoring are not sensitive enough to protect more susceptible invertebrate species such as the amphipod Hyalella azteca and chemical loss during toxicity testing is of concern. In the present study, we quantified toxicity loss during storage and testing, using both natural and synthetic water, and presented a tool to enhance toxic signal strength for improved sensitivity of H. azteca toxicity tests. The average half-life during storage in low-density polyethylene (LDPE) cubitainers (Fisher Scientific) at 4 °C of 5 pyrethroids (permethrin, bifenthrin, lambda-cyhalothrin, cyfluthrin, and esfenvalerate) and one organophosphate (chlorpyrifos; used as reference) was 1.4 d, and piperonyl butoxide (PBO) proved an effective tool to potentiate toxicity. We conclude that toxicity tests on ambient water samples containing these hydrophobic insecticides are likely to underestimate toxicity present in the field, and mimic short pulse rather than continuous exposures. Where these chemicals are of concern, the addition of PBO during testing can yield valuable information on their presence or absence. Environ Toxicol Chem 2018;37:462-472. © 2017 SETAC. © 2017 SETAC.

Enhanced Column Filtration for Arsenic Removal from Water: Polymer-Templated Iron Oxide Nanoparticles Immobilized on Sand via Layer-by-Layer Deposition

NASA Astrophysics Data System (ADS)

Cheng, Calvin Chia-Hung

Arsenic is ubiquitous in water sources around the world and is highly toxic. While precipitation and membrane filtration techniques are successfully implemented in developed cities, they are unsuitable for rural and low-resource settings lacking centralized facilities. This thesis presents the use of ultra-small iron oxide (Fe2O3) nanoparticles functionalized on sand granules for use as a house-hold scale adsorption filter. Water-stable alpha-Fe2O3 (hematite) nanoparticles (<10 nm) were synthesized via a collapsed-polymer approach using poly(acrylic acid) and Fe3+ ions. The nanoparticles exhibited high arsenic adsorption, with 147 +/- 2 mg As(III) per g Fe2O3 and 91 +/- 10 mg As(V) per g Fe2O3. The platform was also used to synthesize iron-based composites, including magnetite (Fe 3O4) and Fe-Cu oxide nanoparticles. For use as a column filter, Fe2O3-PAA nanoparticles were functionalized on sand granules using a layer-by-layer deposition method, with the nanoparticles embedded in the negative layer. The removal of As(III) by the Fe2O 3-PAA functionalized column was described by reversible 1st order kinetics where the forward and reverse rate constants were 0.31 hr -1 and 0.097 hr-1, respectively. Implemented as a passive water filter with 30 x 30 x 50 cm3 dimensions, the filter has an expected lifetime in the order of many years. By controlling the flow rate of the column depending on contamination levels, the filter effectively removes arsenic down to the safety limit of 0.01 mg/L. In a parallel project, the layer-by-layer deposition of Poly(diallydimethyl ammonium chloride) (PDDA) and poly(sodium 5-styrenesulfonate) (PSS) was exploited for a highly practical synthesis of discrete gradient surfaces. By independently controlling the concentration of NaCl in PDDA and PSS deposition solutions, a 2-dimensional matrix of surfaces was created in 96-well microtiter plates. Distinct non-monotonic dye adsorption patterns on the gradient surfaces was observed. Practical

Coastal circulation and water-column properties in the National Park of American Samoa, February–July 2015

USGS Publications Warehouse

Storlazzi, Curt; Cheriton, Olivia; Rosenberger, Kurt; Logan, Joshua; Clark, Timothy B.

2017-06-06

There is little information on the oceanography in the National Park of American Samoa (NPSA). The transport pathways for potentially harmful constituents of land-derived runoff, as well as larvae and other planktonic organisms, are driven by nearshore circulation patterns. To evaluate the processes affecting coral reef ecosystem health, it is first necessary to understand the oceanographic processes driving nearshore circulation, residence times, exposure rates, and transport pathways. Information on how the NPSA’s natural resources may be affected by anthropogenic sources of pollution, sediment runoff, larval transport, or modifications to the marine protected areas is critical to NPSA resource managers for understanding and ultimately managing coastal and marine resources. To address this need, U.S. Geological Survey and U.S. National Park Service researchers conducted a collaborative study in 2015 to determine coastal circulation patterns and water-column properties along north-central Tutuila, American Samoa, in an area focused on NPSA’s Tutuila Unit and its coral reef ecosystem. The continuous measurements of waves, currents, tides, and water-column properties from these instrument deployments over 150 days, coupled with available meteorological measurements of wind and rainfall, provide information on nearshore circulation and the variability in these hydrodynamic properties for NPSA’s Tutuila Unit. In general, circulation was strongly driven by regional winds at longer (greater than day) timescales and by tides at shorter (less than day) timescales. Flows were primarily directed along shore, with current speeds faster offshore to the north and slower closer to shore, especially in embayments. Water-column properties exhibit strong seasonality coupled to the shift from non-trade wind season to trade wind season. During the non-trade wind season that was characterized by variable winds and larger waves in the NPSA, waters were warmer, slightly more

The hyperturbid state of the water column in estuaries and rivers: the importance of hindered settling

NASA Astrophysics Data System (ADS)

Dijkstra, Yoeri M.; Schuttelaars, Henk M.; Winterwerp, Johan C.

2018-03-01

Over the last few decades, some estuaries have undergone a transition to a hyperturbid state, characterised by suspended sediment concentrations of several grammes per litre averaged over the water column. To improve our understanding of this transition and of naturally hyperturbid estuaries, we systematically identify the processes allowing for high suspended sediment concentrations using a water column (1DV) model. Under a range of realistic forcing conditions, the state of the water column can be characterised by one of two equilibrium states. The first is an erosion-limited state, in which there still is sediment available for erosion at the bed. We find that this state only occurs with relatively low concentrations. The second is a supply-limited state, in which all erodable sediment is in suspension. The concentration in this state depends entirely on the amount of sediment in the system and can potentially be very high. We identify the conditions under which the state of the water column can jump from a low to a high concentration and identify hysteresis in the transition between the two states. The mechanism responsible for this hysteresis is hindered settling. It thus follows that hyperturbidity is only possible in a supply-limited state. From this observation we derive a necessary condition for an estuarine system to make the transition from low turbidity to hyperturbidity in a 1DV context. This is an important step towards understanding why some estuaries are hyperturbid and assessing the risk that particular estuaries may become hyperturbid in the future.

Application of two low-cost adsorption media for removal of toxic metals from contaminated water.

PubMed

Somerville, R; Norrström, A C

2009-01-01

Since the operational costs of commonly used materials for adsorption of toxic metals can be substantial, natural material may be of great interest for treatment applications. Two types of natural material that have shown particular promise are seaweed and seafood waste. In this study, adsorption capacity of Brown seaweed and shrimp shells were compared with a strong acid cation exchange resin (CER). A case study site was used as a reference point and column experiments were designed in a similar manner although at different scale. Each media reduced concentrations of the target metals to levels below defined reference values. If the alternative adsorption media perform as well in the field as the laboratory, the results suggest that the media tested would completely remove the toxic metals in groundwater and runoff water. Seaweed and shrimp shells had stronger affinities for Pb and Cu than CER. However, CER was superior in affinity for Zn, the most weakly bound metal. Moreover, the results showed that Ca in the solution reduced the adsorption capacity of the other metals. This illustrates the limitations of applying the behaviour of the batch studies with single metal solutions to a multi-component system with competitive adsorption.

E. coli release from streambed to water column during base flow periods: a modeling study

USDA-ARS?s Scientific Manuscript database

Microbial quality of stream water is important for recreation, irrigation, and other uses. It is usually evaluated by concentrations of fecal indicator bacteria (FIB) such as E. coli. Streambed sediments have been shown to harbor large FIB populations that could be released into the water column dur...

Design of Stripping Columns Applied to Drinking Water to Minimize Carcinogenic Risk from Trihalomethanes (THMs)

PubMed Central

Canosa, Joel

2018-01-01

The aim of this study is the application of a software tool to the design of stripping columns to calculate the removal of trihalomethanes (THMs) from drinking water. The tool also allows calculating the rough capital cost of the column and the decrease in carcinogenic risk indeces associated with the elimination of THMs and, thus, the investment to save a human life. The design of stripping columns includes the determination, among other factors, of the height (HOG), the theoretical number of plates (NOG), and the section (S) of the columns based on the study of pressure drop. These results have been compared with THM stripping literature values, showing that simulation is sufficiently conservative. Three case studies were chosen to apply the developed software. The first case study was representative of small-scale application to a community in Córdoba (Spain) where chloroform is predominant and has a low concentration. The second case study was of an intermediate scale in a region in Venezuela, and the third case study was representative of large-scale treatment of water in the Barcelona metropolitan region (Spain). Results showed that case studies with larger scale and higher initial risk offer the best capital investment to decrease the risk. PMID:29562670

4SM: A Novel Self-Calibrated Algebraic Ratio Method for Satellite-Derived Bathymetry and Water Column Correction

PubMed Central

Morel, Yann G.; Favoretto, Fabio

2017-01-01

All empirical water column correction methods have consistently been reported to require existing depth sounding data for the purpose of calibrating a simple depth retrieval model; they yield poor results over very bright or very dark bottoms. In contrast, we set out to (i) use only the relative radiance data in the image along with published data, and several new assumptions; (ii) in order to specify and operate the simplified radiative transfer equation (RTE); (iii) for the purpose of retrieving both the satellite derived bathymetry (SDB) and the water column corrected spectral reflectance over shallow seabeds. Sea truth regressions show that SDB depths retrieved by the method only need tide correction. Therefore it shall be demonstrated that, under such new assumptions, there is no need for (i) formal atmospheric correction; (ii) conversion of relative radiance into calibrated reflectance; or (iii) existing depth sounding data, to specify the simplified RTE and produce both SDB and spectral water column corrected radiance ready for bottom typing. Moreover, the use of the panchromatic band for that purpose is introduced. Altogether, we named this process the Self-Calibrated Supervised Spectral Shallow-sea Modeler (4SM). This approach requires a trained practitioner, though, to produce its results within hours of downloading the raw image. The ideal raw image should be a “near-nadir” view, exhibit homogeneous atmosphere and water column, include some coverage of optically deep waters and bare land, and lend itself to quality removal of haze, atmospheric adjacency effect, and sun/sky glint. PMID:28754028

4SM: A Novel Self-Calibrated Algebraic Ratio Method for Satellite-Derived Bathymetry and Water Column Correction.

PubMed

Morel, Yann G; Favoretto, Fabio

2017-07-21

All empirical water column correction methods have consistently been reported to require existing depth sounding data for the purpose of calibrating a simple depth retrieval model; they yield poor results over very bright or very dark bottoms. In contrast, we set out to (i) use only the relative radiance data in the image along with published data, and several new assumptions; (ii) in order to specify and operate the simplified radiative transfer equation (RTE); (iii) for the purpose of retrieving both the satellite derived bathymetry (SDB) and the water column corrected spectral reflectance over shallow seabeds. Sea truth regressions show that SDB depths retrieved by the method only need tide correction. Therefore it shall be demonstrated that, under such new assumptions, there is no need for (i) formal atmospheric correction; (ii) conversion of relative radiance into calibrated reflectance; or (iii) existing depth sounding data, to specify the simplified RTE and produce both SDB and spectral water column corrected radiance ready for bottom typing. Moreover, the use of the panchromatic band for that purpose is introduced. Altogether, we named this process the Self-Calibrated Supervised Spectral Shallow-sea Modeler (4SM). This approach requires a trained practitioner, though, to produce its results within hours of downloading the raw image. The ideal raw image should be a "near-nadir" view, exhibit homogeneous atmosphere and water column, include some coverage of optically deep waters and bare land, and lend itself to quality removal of haze, atmospheric adjacency effect, and sun/sky glint.

DETERMINING THE CAUSES OF ADVERSE EFFECTS IN NEAR COASTAL ECOSYSTEMS: FROM TOXICITY IDENTIFICATION EVALUATIONS TO WATERSHED DIAGNOTICS

EPA Science Inventory

Several approaches are available for evaluating adverse effects in near coastal ecosystems. These range from performing toxicity tests with individual organisms on water column and sediment samples to conducting macrofaunal compositional analyses on pelagic and benthic communiti...

USE OF COMPOSITE DATA SETS FOR SOURCE-TRACKING ENTEROCCOCCI IN THE WATER COLUMN AND SHORELINE INTERSTITIAL WATERS ON PENSACOLA BEACH, FL

EPA Science Inventory

Genthner, Fred J., Joseph B. James, Diane F. Yates and Stephanie D. Friedman. Submitted. Use of Composite Data Sets for Source-Tracking Enterococci in the Water Column and Shoreline Interstitial Waters on Pensacola Beach Florida. Mar. Pollut. Bull. 33 p. (ERL,GB 1212).

So...

Nitrification and the ammonia-oxidizing communities in the central Baltic Sea water column

NASA Astrophysics Data System (ADS)

Jäntti, Helena; Ward, Bess B.; Dippner, Joachim W.; Hietanen, Susanna

2018-03-01

The redoxclines that form between the oxic and anoxic water layers in the central Baltic Sea are sites of intensive nitrogen cycling. To gain better understanding of nitrification, we measured the biogeochemical properties along with potential nitrification rates and analyzed the assemblages of ammonia-oxidizing bacteria and archaea using functional gene microarrays. To estimate nitrification in the entire water column, we constructed a regression model for the nitrification rates and applied it to the conditions prevailing in the area in 2008-2012. The highest ammonia oxidation rates were found in a thin layer at the top of the redoxcline and the rates quickly decreased below detection limit when oxygen was exhausted. This is probably because extensive suboxic layers, which are known to harbor pelagic nitrification, are formed only for short periods after inflows in the Baltic Sea. The nitrification rates were some of the highest measured in the water columns, but the thickness of the layer where conditions were favorable for nitrification, was very small and it remained fairly stable between years. However, the depth of the nitrification layer varied substantially between years, particularly in the eastern Gotland Basin (EGB) due to turbulence in the water column. The ammonia oxidizer communities clustered differently between the eastern and western Gotland Basin (WGB) and the composition of ammonia-oxidizing assemblages correlated with the environmental variables. The ammonia oxidizer community composition was more even in the EGB, which may be related to physical instability of the redoxcline that does not allow predominance of a single archetype, whereas in the WGB, where the position of the redoxcline is more constant, the ammonia-oxidizing community was less even. Overall the ammonia-oxidizing communities in the Baltic Sea redoxclines were very evenly distributed compared to other marine environments where microarrays have been applied previously.

Anomalies of the upper water column in the Mediterranean Sea

NASA Astrophysics Data System (ADS)

Rivetti, Irene; Boero, Ferdinando; Fraschetti, Simonetta; Zambianchi, Enrico; Lionello, Piero

2017-04-01

The evolution of the upper water column in the Mediterranean Sea during more than 60 years is reconstructed in terms of few parameters describing the mixed layer and the seasonal thermocline. The analysis covers the period 1945-2011 using data from three public sources: MEDAR-MEDATLAS, World Ocean Database, MFS-VOS program. Five procedures for estimating the mixed layer depth are described, discussed and compared using the 20-year long time series of temperature profiles of the DYFAMED station in the Ligurian Sea. On this basis the so-called three segments profile model (which approximates the upper water column with three segments representing mixed layer, thermocline and deep layer) has been selected for a systematic analysis at Mediterranean scale. A widespread increase of the thickness and temperature of the mixed layer, increase of the depth and decrease of the temperature of the thermocline base have been observed in summer and autumn during the recent decades. It is shown that positive temperature extremes of the mixed layer and of its thickness are potential drivers of the mass mortalities of benthic invertebrates documented since 1983. Hotspots of mixed layer anomalies have been also identified. These results refine previous analyses showing that ongoing and future warming of upper Mediterranean is likely to increase mass mortalities by producing environmental conditions beyond the limit of tolerance of some benthic species.

A mass-balance code for the quantitative interpretation of fluid column profiles in ground-water studies

NASA Astrophysics Data System (ADS)

Paillet, Frederick

2012-08-01

A simple mass-balance code allows effective modeling of conventional fluid column resistivity logs in dilution tests involving column replacement with either distilled water or dilute brine. Modeling a series of column profiles where the inflowing formation water introduces water quality interfaces propagating along the borehole gives effective estimates of the rate of borehole flow. Application of the dilution model yields estimates of borehole flow rates that agree with measurements made with the heat-pulse flowmeter under ambient and pumping conditions. Model dilution experiments are used to demonstrate how dilution logging can extend the range of borehole flow measurement at least an order of magnitude beyond that achieved with flowmeters. However, dilution logging has the same dynamic range limitation encountered with flowmeters because it is difficult to detect and characterize flow zones that contribute a small fraction of total flow when that contribution is superimposed on a larger flow. When the smaller contribution is located below the primary zone, ambient downflow may disguise the zone if pumping is not strong enough to reverse the outflow. This situation can be addressed by increased pumping. But this is likely to make the moveout of water quality interfaces too fast to measure in the upper part of the borehole, so that a combination of flowmeter and dilution method may be more appropriate. Numerical experiments show that the expected weak horizontal flow across the borehole at conductive zones would be almost impossible to recognize if any ambient vertical flow is present. In situations where natural water quality differences occur such as flowing boreholes or injection experiments, the simple mass-balance code can be used to quantitatively model the evolution of fluid column logs. Otherwise, dilution experiments can be combined with high-resolution flowmeter profiles to obtain results not attainable using either method alone.

Polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides in water columns from the Pearl River and the Macao harbor in the Pearl River Delta in South China.

PubMed

Luo, Xiaojun; Mai, Bixian; Yang, Qingshu; Fu, Jiamo; Sheng, Guoying; Wang, Zhishi

2004-06-01

Polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) were measured in suspended particles and dissolved phase from the Baiertang water column and the Macao water column samples as collected from the Guangzhou channel of the Pearl River and the Macao harbor, where the sediments were heavily contaminated with organic pollutants. Total OCPs concentration varies from 23.4 to 61.7 ng/l in Baiertang water column and from 25.2 to 67.8 ng/l in Macao column, while total PAHs concentration varies from 987.1 to 2878.5 ng/l in the Baiertang water column and from 944.0 to 6654.6 ng/l in the Macao column. The vertical distribution profiles of pollutants and the partition of pollutants between particles and dissolved phases indicate that the sediments in Baiertang act as an important source of selected pollutants, and the pollutants in water of this region were mainly originated from the release and re-suspension of contaminants residing in the sediments. The sediments in Macao harbor act as a reservoir for organochlorine pesticides, such as DDTs mainly introduced by river inflow from Xijiang and PAHs input by brackish water from the Lingdingyang estuary. Combustion of fossil fuels and petroleum input are the main sources of PAHs in the Macao water column, while combustion of fossil fuels and coal is responsible for the PAHs in the Baiertang water column. The ratios of DDT/(DDD+DDE) for the Macao water column samples demonstrate that such chemicals were input into this region in recent times.

Involvement of cell shape and flagella in the bacterial retention during percolation of contaminated water through soil columns in tropical region.

PubMed

Nola, Moise; Ewoti, Olive V Noah; Nougang, Mireille; Moungang, Marlyse L; Chihib, Nour-Eddine; Krier, Francois; Servais, Pierre; Hornez, Jean-Pierre; Njine, Thomas

2010-09-01

Microorganisms' retention in soil contributes to the natural purification of groundwater. Bacteria found in groundwater are generally of various shapes. The aim of this study was to assess the importance of cell shape and flagella in bacterial retention during polluted water percolation through two soil columns CA and CB, in the equatorial region in Central Africa. Percolation tests were carried out using different water loads samples which were contaminated by Escherichia coli (straight rods, peritrichous flagella), Vibrio parahaemolyticus (rods bacteria, polar flagella), and Staphylococcus saprophyticus (spherical, free-flagellum). It has been noted that showed that through soil column CA, the mean values of cells retention ratios (T(R)) varied with bacteria species considered, and from one applied water load sample to another. E. coli T(R) and that of S. saprophyticus were not significantly different (P> 0.05) for the two soil columns. V. parahaemolyticus T(R) significantly differed from that of E. coli and S. saprophyticus through soil column CA (P< 0.01) when the highest water load was applied, and through soil column CB (P< 0.05) for each of water load applied. A relative hierarchical arrangement of retained cells based on the T(R) showed that V. parahaemolyticus was less retained through the 2 soil columns. S. saprophyticus in most cases was more retained than others. The physical properties of the bacterial cell must be taken into consideration when evaluating the transfer of bacteriological pollutants towards groundwater.

Applicability of ambient toxicity testing to national or regional water-quality assessment

USGS Publications Warehouse

Elder, John F.

1990-01-01

Comprehensive assessment of the quality of natural waters requires a multifaceted approach. Descriptions of existing conditions may be achieved by various kinds of chemical and hydrologic analyses, whereas information about the effects of such conditions on living organisms depends on biological monitoring. Toxicity testing is one type of biological monitoring that can be used to identify possible effects of toxic contaminants. Based on experimentation designed to monitor responses of organisms to environmental stresses, toxicity testing may have diverse purposes in water-quality assessments. These purposes may include identification of areas that warrant further study because of poor water quality or unusual ecological features, verification of other types of monitoring, or assessment of contaminant effects on aquatic communities. Toxicity-test results are most effective when used as a complement to chemical analyses, hydrologic measurements, and other biological monitoring. However, all toxicity-testing procedures have certain limitations that must be considered in developing the methodology and applications of toxicity testing in any large-scale water-quality-assessment program. A wide variety of toxicity-test methods have been developed to fulfill the needs of diverse applications. The methods differ primarily in the selections made relative to four characteristics: (1) test species, (2) endpoint (acute or chronic), (3) test-enclosure type, and (4) test substance (toxicant) that functions as the environmental stress. Toxicity-test approaches vary in their capacity to meet the needs of large-scale assessments of existing water quality. Ambient testing, whereby the test organism is exposed to naturally occurring substances that contain toxicant mixtures in an organic or inorganic matrix, is more likely to meet these needs than are procedures that call for exposure of the test organisms to known concentrations of a single toxicant. However, meaningful

Porewater inputs drive Fe redox cycling in the water column of a temperate mangrove wetland

NASA Astrophysics Data System (ADS)

Holloway, Ceylena J.; Santos, Isaac R.; Rose, Andrew L.

2018-07-01

Iron is a vital micronutrient within coastal marine ecosystems, playing an integral role in the scale and dynamics of primary production and carbon cycling in the world's oceans. We investigated the relative importance of in situ Fe(II) production from photochemical, microbial and thermal Fe reduction in the surface water column as well as advective porewater inputs in a temperate saline wetland in Australia containing mangrove and saltmarsh vegetation. The diel average concentration of Fe(II) (0.63 ± 0.21 μM, accounting for >70% of the total dissolved Fe present in surface water) was much higher than commonly reported in oxygenated marine waters despite high dissolved oxygen concentrations (81-112% saturation), pH (7.7-7.8) and salinity (33-36) that favor Fe oxidation. In situ production of Fe(II) in the surface water column was primarily driven by microbial processes rather than photochemical and thermal reduction, with a maximum production rate of 4.9 × 10-3 nM s-1. Advective porewater Fe(II) inputs to the wetland averaged over a diel cycle (3.0 × 10-1 nM s-1) were an order of magnitude greater than the combined Fe(II) production rate from autochthonous water column processes (1.0 × 10-2 nM s-1). A bottom up model based on the estimated individual fluxes was used to explain the high Fe(II) concentrations measured during a 24 h time series experiment. Combined, different lines of evidence suggest that advective porewater exchange provides significant quantities of Fe(II) to the estuarine wetland.

Water quality and nitrogen mass loss from anaerobic lagoon columns receiving pretreated influent

USDA-ARS?s Scientific Manuscript database

Control methods are needed to abate ammonia losses from swine anaerobic lagoons to reduce contribution of confined swine operations to air pollution. In a 15-month meso-scale column study, we evaluated the effect of manure pretreatment on water quality, reduction of N losses, and sludge accumulation...

40 CFR 799.6756 - TSCA partition coefficient (n-octanol/water), generator column method.

Code of Federal Regulations, 2013 CFR

2013-07-01

... method, or any other reliable quantitative procedure must be used for those compounds that do not absorb... any other reliable quantitative method, aqueous solutions from the generator column enter a collecting... Solubilities and Octanol-Water Partition Coefficients of Hydrophobic Substances,” Journal of Research of the...

40 CFR 799.6756 - TSCA partition coefficient (n-octanol/water), generator column method.

Code of Federal Regulations, 2014 CFR

2014-07-01

... method, or any other reliable quantitative procedure must be used for those compounds that do not absorb... any other reliable quantitative method, aqueous solutions from the generator column enter a collecting... Solubilities and Octanol-Water Partition Coefficients of Hydrophobic Substances,” Journal of Research of the...

Evaluating the precision of passive sampling methods using PRCs in the water column.

EPA Science Inventory

To assess these models, four different thicknesses of low-density polyethylene (LDPE) passive samplers were co-deployed for 28 days in the water column at three sites in New Bedford Harbor, MA, USA. Each sampler was pre-loaded with six PCB performance reference compounds (PRCs) t...

Water column particulate matter: A key contributor to phosphorus regeneration in a coastal eutrophic environment, the Chesapeake Bay: Particulate phosphorus in the Chesapeake Bay

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Jiying; Reardon, Patrick; McKinley, James P.

Particulate phosphorus (PP) in the water column is an essential component of phosphorus (P) cycling in aquatic ecosystems yet its composition and transformations remain largely uncharacterized. To understand the roles of suspended particulates on regeneration of inorganic P (Pi) into the water column as well as sequestration into more stable mineral precipitates, we studied seasonal variation in both organic and inorganic P speciation in suspended particles in three sites in the Chesapeake Bay using sequential P extraction, 1D (31P) and 2D (1H-31P) nuclear magnetic resonance (NMR) spectroscopies, and electron microprobe analyses (EMPA). Remineralization efficiency of particulate P average 8% andmore » 56% in shallow and deep sites respectively, suggesting the importance of PP remineralization is in resupplying water column Pi. Strong temporal and spatial variability of organic P composition, distributions, and remineralization efficiency were observed relating to water column parameters such as temperature and redox conditions: concentration of orthophosphate monoesters and diesters, and diester-to-monoester (D/M) ratios decreased with depth. Both esters and the D/M ratios were lower in the hypoxic July and September. In contrast, pyrophosphate and orthophosphate increased with depth, and polyphosphates was high in the anoxic water column. Sequential extraction and EMPA analyses of the suspended particles suggest presence of Ca-bound phosphate in the water column. We hypothesize authigenic precipitation of carbonate fluorapatite and/or its precursor mineral(s) in Pi rich water column, supported by our thermodynamic calculations. Our results, overall, reveal the important role suspended particles play in P remineralization and P sequestration in the Chesapeake Bay water column, provide important implications on P bioavailability and P sinks in similar eutrophic coastal environments.« less

Applicability of ambient toxicity testing to national or regional water-quality assessment

USGS Publications Warehouse

Elder, J.F.

1989-01-01

Comprehensive assessment of the quality of natural waters requires a multifaceted approach. Based on experimentation designed to monitor responses of organisms to environmental stresses, toxicity testing may have diverse purposes in water quality assessments. These purposes may include identification that warrant further study because of poor water quality or unusual ecological features, verification of other types of monitoring, or assessment of contaminant effects on aquatic communities. A wide variety of toxicity test methods have been developed to fulfill the needs of diverse applications. The methods differ primarily in the full selections made relative to four characteristics: (1) test species, (2) endpoints (acute or chronic), (3) test enclosure type, and (4) test substance (toxicant) that functions as the environmental stress. Toxicity test approachs vary in their capacity to meet the needs of large-scale assessments of existing water quality. Ambient testing is more likely to meet these needs than are the procedures that call for exposure of the test organisms to known concentrations of a single toxicant. However, meaningful interpretation of ambient test results depend on the existence of accompanying chemical analysis of the ambient media. The ambient test substance may be water or sediments. Sediment tests have had limited application, but they are useful because of the fact that most toxicants tend to accumulate in sediments, and many test species either inhabit the sediments or are in frequent contact with them. Biochemical testing methods, which have been developing rapidly in recent years, are likely to be among the most useful procedures for large-scale water quality assessments. They are relatively rapid and simple, and more importantly, they focus on biochemical changes that are the initial responses of virtually all organisms to environmental stimuli. Most species are sensitive to relatively few toxicants and their sensitivities vary as

A Microfluidic Device for Continuous Sensing of Systemic Acute Toxicants in Drinking Water

PubMed Central

Zhao, Xinyan; Dong, Tao

2013-01-01

A bioluminescent-cell-based microfluidic device for sensing toxicants in drinking water was designed and fabricated. The system employed Vibrio fischeri cells as broad-spectrum sensors to monitor potential systemic cell toxicants in water, such as heavy metal ions and phenol. Specifically, the chip was designed for continuous detection. The chip design included two counter-flow micromixers, a T-junction droplet generator and six spiral microchannels. The cell suspension and water sample were introduced into the micromixers and dispersed into droplets in the air flow. This guaranteed sufficient oxygen supply for the cell sensors. Copper (Cu2+), zinc (Zn2+), potassium dichromate and 3,5-dichlorophenol were selected as typical toxicants to validate the sensing system. Preliminary tests verified that the system was an effective screening tool for acute toxicants although it could not recognize or quantify specific toxicants. A distinct non-linear relationship was observed between the zinc ion concentration and the Relative Luminescence Units (RLU) obtained during testing. Thus, the concentration of simple toxic chemicals in water can be roughly estimated by this system. The proposed device shows great promise for an early warning system for water safety. PMID:24300075

Primary production export flux in Marguerite Bay (Antarctic Peninsula): Linking upper water-column production to sediment trap flux

NASA Astrophysics Data System (ADS)

Weston, Keith; Jickells, Timothy D.; Carson, Damien S.; Clarke, Andrew; Meredith, Michael P.; Brandon, Mark A.; Wallace, Margaret I.; Ussher, Simon J.; Hendry, Katharine R.

2013-05-01

A study was carried out to assess primary production and associated export flux in the coastal waters of the western Antarctic Peninsula at an oceanographic time-series site. New, i.e., exportable, primary production in the upper water-column was estimated in two ways; by nutrient deficit measurements, and by primary production rate measurements using separate 14C-labelled radioisotope and 15N-labelled stable isotope uptake incubations. The resulting average annual exportable primary production estimates at the time-series site from nutrient deficit and primary production rates were 13 and 16 mol C m-2, respectively. Regenerated primary production was measured using 15N-labelled ammonium and urea uptake, and was low throughout the sampling period. The exportable primary production measurements were compared with sediment trap flux measurements from 2 locations; the time-series site and at a site 40 km away in deeper water. Results showed ˜1% of the upper mixed layer exportable primary production was exported to traps at 200 m depth at the time-series site (total water column depth 520 m). The maximum particle flux rate to sediment traps at the deeper offshore site (total water column depth 820 m) was lower than the flux at the coastal time-series site. Flux of particulate organic carbon was similar throughout the spring-summer high flux period for both sites. Remineralisation of particulate organic matter predominantly occurred in the upper water-column (<200 m depth), with minimal remineralisation below 200 m, at both sites. This highly productive region on the Western Antarctic Peninsula is therefore best characterised as 'high recycling, low export'.

Environmental Characterization of Mine Countermeasure Test Ranges: Hydrography and Water Column Optics

DTIC Science & Technology

2015-09-30

changes in near-shore water columns and support companion laser imaging system tests. The physical, biological and optical oceanographic data...developed under this project will be used as input to optical and environmental models to assess the performance characteristics of laser imaging systems...OBJECTIVES We proposed to characterize the physical, biological and optical fields present during deployments of the Streak Tube Imaging Lidar

Sediment pore-water toxicity test results and preliminary toxicity identification of post-landfall pore-water samples collected following the Deepwater Horizon oil release, Gulf of Mexico, 2010

USGS Publications Warehouse

Biedenbach, James M.; Carr, Robert S.

2011-01-01

Pore water from coastal beach and marsh sediments from the northern Gulf of Mexico, pre- and post-landfall of the Deepwater Horizon oil release, were collected and evaluated for toxicity with the sea urchin fertilization and embryological development assays. There were 17 pre-landfall samples and 49 post-landfall samples tested using both assays. Toxicity was determined in four pre-landfall sites and in seven post-landfall sites in one or both assays as compared to a known reference sediment pore-water sample collected in Aransas Bay, Texas. Further analysis and testing of five of the post-landfall toxic samples utilizing Toxicity Identification Evaluation techniques indicated that ammonia, and to a lesser extent metals, contributed to most, if not all, of the observed toxicity in four of the five samples. Results of one sample (MS-39) indicated evidence that ammonia, metals, and non-ionic organics were contributing to the observed toxicity.

Planktonic Marine Luminous Bacteria: Species Distribution in the Water Column

PubMed Central

Ruby, E. G.; Greenberg, E. P.; Hastings, J. W.

1980-01-01

Luminous bacteria were isolated from oceanic water samples taken throughout the upper 1,000 m and ranged in density from 0.4 to 30 colony-forming units per 100 ml. Generally, two peaks in abundance were detected: one in the upper 100 m of the water column, which consisted primarily of Beneckea spp.; and a second between 250 and 1,000 m, which consisted almost entirely of Photobacterium phosphoreum. The population of P. phosphoreum remained relatively stable in abundance at one station that was visited three times over a period of 6 months. However, the abundance of luminous Beneckea spp. isolated from the upper waters fluctuated considerably; they were, as high as 30 colony-forming units per 100 ml in the spring and were not detected in the winter. Water samples from depths of 4,000 to 7,000 m contained less than 0.1 luminous colony-forming unit per 100 ml. The apparent vertical stratification of two taxa of oceanic luminous bacteria may reflect not only differences in physiology, but also depth-related, species-specific symbiotic associations. PMID:16345502

Ether Lipids of Planktonic Archaea in the Marine Water Column

PubMed Central

Hoefs, M.; Schouten, S.; De Leeuw, J. W.; King, L. L.; Wakeham, S. G.; Damste, J.

1997-01-01

Acyclic and cyclic biphytanes derived from the membrane ether lipids of archaea were found in water column particulate and sedimentary organic matter from several oxic and anoxic marine environments. Compound-specific isotope analyses of the carbon skeletons suggest that planktonic archaea utilize an isotopically heavy carbon source such as algal carbohydrates and proteins or dissolved bicarbonate. Due to their high preservation potential, these lipids provide a fossil record of planktonic archaea and suggest that they have thrived in marine environments for more than 50 million years. PMID:16535669

Dissolved sulfides in the oxic water column of San Francisco Bay, California

USGS Publications Warehouse

Kuwabara, J.S.; Luther, G.W.

1993-01-01

Trace contaminants enter major estuaries such as San Francisco Bay from a variety of point and nonpoint sources and may then be repartitioned between solid and aqueous phases or altered in chemical speciation. Chemical speciation affects the bioavailability of metals as well as organic ligands to planktonic and benthic organisms, and the partitioning of these solutes between phases. Our previous, work in south San Francisco Bay indicated that sulfide complexation with metals may be of particular importance because of the thermodynamic stability of these complexes. Although the water column of the bay is consistently well-oxygenated and typically unstratified with respect to dissolved oxygen, the kinetics of sulfide oxidation could exert at least transient controls on metal speciation. Our initial data on dissolved sulfides in the main channel of both the northern and southern components of the bay consistently indicate submicromolar concenrations (from <1 nM to 162 nM), as one would expect in an oxidizing environment. However, chemical speciation calculations over the range of observed sulfide concentrations indicate that these trace concentrations in the bay water column can markedly affect chemical speciation of ecologically significant trace metals such as cadmium, copper, and zinc.

Formation and control of disinfection byproducts and toxicity during reclaimed water chlorination: A review.

PubMed

Du, Ye; Lv, Xiao-Tong; Wu, Qian-Yuan; Zhang, Da-Yin; Zhou, Yu-Ting; Peng, Lu; Hu, Hong-Ying

2017-08-01

Chlorination is essential to the safety of reclaimed water; however, this process leads to concern regarding the formation of disinfection byproducts (DBPs) and toxicity. This study reviewed the formation and control strategies for DBPs and toxicity in reclaimed water during chlorination. Both regulated and emerging DBPs have been frequently detected in reclaimed water during chlorination at a higher level than those in drinking water, indicating they pose a greater risk to humans. Luminescent bacteria and Daphnia magna acute toxicity, anti-estrogenic activity and cytotoxicity generally increased after chlorination because of the formation of DBPs. Genotoxicity by umu-test and estrogenic activity were decreased after chlorination because of destruction of toxic chemicals. During chlorination, water quality significantly impacted changes in toxicity. Ammonium tended to attenuate toxicity changes by reacting with chlorine to form chloramine, while bromide tended to aggravate toxicity changes by forming hypobromous acid. During pretreatment by ozonation and coagulation, disinfection byproduct formation potential (DBPFP) and toxicity formation potential (TFP) occasionally increase, which is accompanied by DOC removal; thus, the decrease of DOC was limited to indicate the decrease of DBPFP and TFP. It is more important to eliminate the key fraction of precursors such as hydrophobic acid and hydrophilic neutrals. During chlorination, toxicities can increase with the increasing chlorine dose and contact time. To control the excessive toxicity formation, a relatively low chlorine dose and short contact time were required. Quenching chlorine residual with reductive reagents also effectively abated the formation of toxic compounds. Copyright © 2017. Published by Elsevier B.V.

Impact of Madden-Julian Oscillation (MJO) on global distribution of total water vapor and column ozone

NASA Astrophysics Data System (ADS)

Fathurochman, Irvan; Lubis, Sandro W.; Setiawan, Sonni

2017-01-01

The Madden-Julian Oscillation (MJO) is the leading mode of intra-seasonal variability in the tropical troposphere, characterized by an eastward moving ‘pulse’ of cloud and rainfall near the equator. In this study, total precipitable water (TPW) and total column ozone (TCO) datasets from ECMWF ERA-Interim reanalysis were used to analyse the impact of the MJO on the distribution of water vapor and column ozone in the tropics from 1979 to 2013. The results show that seasonal variations of TPW modulated by the MJO are maximized in the tropics of about 10°S-10°N during boreal winter, while the variation in TCO is maximized in the mid-latitudes of about 30°S - 40°N in the same season. The composite analysis shows that MJO modulates TPW and TCO anomalies eastward across the globe. The underlying mechanism of the MJO’s impact on TPW is mainly associated with variation of tropical convection modulated by the MJO, while the underlying mechanism of the MJO’s impact on TCO is mainly associated with an intra-seasonal variability of tropopause height modulated by the MJO activity. This knowledge helps to improve the prediction skill of the intra-seasonal variation of water vapor and column ozone in the tropics during boreal winter.

Evaluation of a novel automated water analyzer for continuous monitoring of toxicity and chemical parameters in municipal water supply.

PubMed

Bodini, Sergio F; Malizia, Marzio; Tortelli, Annalisa; Sanfilippo, Luca; Zhou, Xingpeng; Arosio, Roberta; Bernasconi, Marzia; Di Lucia, Stefano; Manenti, Angela; Moscetta, Pompeo

2018-08-15

A novel tool, the DAMTA analyzer (Device for Analytical Monitoring and Toxicity Assessment), designed for fully automated toxicity measurements based on luminescent bacteria as well as for concomitant determination of chemical parameters, was developed and field-tested. The instrument is a robotic water analyzer equipped with a luminometer and a spectrophotometer, integrated on a thermostated reaction plate which contains a movable carousel with 80 cuvettes. Acute toxicity is measured on-line using a wild type Photobacterium phosphoreum strain with measurable bioluminescence and unaltered sensitivity to toxicants lasting up to ten days. The EC50 values of reference compounds tested were consistent with A. fischeri and P. phosphoreum international standards and comparable to previously published data. Concurrently, a laboratory trial demonstrated the feasibility of use of the analyzer for the determination of nutrients and metals in parallel to the toxicity measurements. In a prolonged test, the system was installed only in toxicity mode at the premises of the World Fair "Expo Milano-2015″, a high security site to ensure the quality of the supplied drinking water. The monitoring program lasted for six months during which ca. 2400 toxicity tests were carried out; the results indicated a mean non-toxic outcome of -5.5 ± 6.2%. In order to warrant the system's robustness in detecting toxic substances, Zn was measured daily with highly reproducible inhibition results, 70.8 ± 13.6%. These results assure that this novel toxicity monitor can be used as an early warning system for protection of drinking water sources from emergencies involving low probability/high impact contamination events in source water or treated water. Copyright © 2018 Elsevier Inc. All rights reserved.

Toxicity of sediments and pore water from Brunswick Estuary, Georgia

USGS Publications Warehouse

Winger, Parley V.; Lasier, Peter J.; Geitner, Harvey

1993-01-01

A chlor-alkali plant in Brunswick, Georgia, USA, discharged >2 kg mercury/d into a tributary of the Turtle River-Brunswick Estuary from 1966 to 1971. Mercury concentrations in sediments collected in 1989 along the tributary near the chlor-alkali plant ranged from 1 to 27 μg/g (dry weight), with the highest concentrations found in surface (0–8 cm) sediments of subtidal zones in the vicinity of the discharge site. Toxicity screening in 1990 using Microtox® bioassays on pore water extracted on site from sediments collected at six stations distributed along the tributary indicated that pore water was highly toxic near the plant discharge. Ten-day toxicity tests on pore water from subsequent sediment samples collected near the plant discharge confirmed high toxicity to Hyalella azteca, and feeding activity was significantly reduced in whole-sediment tests. In addition to mercury in the sediments, other metals (chromium, lead, and zinc) exceeded 50 μg/g, and polychlorobiphenyl (PCB) concentrations ranged from 67 to 95 μg/g. On a molar basis, acid-volatile sulfide concentrations (20–45 μmol/g) in the sediments exceeded the metal concentrations. Because acid-volatile sulfides bind with cationic metals and form metal sulfides, which are generally not bioavailable, toxicities shown by these sediments were attributed to the high concentrations of PCBs and possibly methylmercury.

Properties of the Water Column and Bottom Derived from AVIRIS Data

NASA Technical Reports Server (NTRS)

Lee, Zhong-Ping; Carder, Kendall L.; Chen, F. Robert; Peacock, Thomas G.

2001-01-01

Using AVIRIS data as an example, we show in this study that the optical properties of the water column and bottom of a large, shallow area can be adequately retrieved using a model-driven optimization technique. The simultaneously derived properties include bottom depth, bottom albedo, and water absorption and backscattering coefficients, which in turn could be used to derive concentrations of chlorophyll, dissolved organic matter, and suspended sediments. The derived bottom depths were compared with a bathymetry chart and a boat survey and were found to agree very well. Also, the derived bottom-albedo image shows clear spatial patterns, with end members consistent with sand and seagrass. The image of absorption and backscattering coefficients indicates that the water is quite horizontally mixed. These results suggest that the model and approach used work very well for the retrieval of sub-surface properties of shallow-water environments even for rather turbid environments like Tampa Bay, Florida.

Quantifying Methane Flux from a Prominent Seafloor Crater with Water Column Imagery Filtering and Bubble Quantification Techniques

NASA Astrophysics Data System (ADS)

Mitchell, G. A.; Gharib, J. J.; Doolittle, D. F.

2015-12-01

Methane gas flux from the seafloor to atmosphere is an important variable for global carbon cycle and climate models, yet is poorly constrained. Methodologies used to estimate seafloor gas flux commonly employ a combination of acoustic and optical techniques. These techniques often use hull-mounted multibeam echosounders (MBES) to quickly ensonify large volumes of the water column for acoustic backscatter anomalies indicative of gas bubble plumes. Detection of these water column anomalies with a MBES provides information on the lateral distribution of the plumes, the midwater dimensions of the plumes, and their positions on the seafloor. Seafloor plume locations are targeted for visual investigations using a remotely operated vehicle (ROV) to determine bubble emission rates, venting behaviors, bubble sizes, and ascent velocities. Once these variables are measured in-situ, an extrapolation of gas flux is made over the survey area using the number of remotely-mapped flares. This methodology was applied to a geophysical survey conducted in 2013 over a large seafloor crater that developed in response to an oil well blowout in 1983 offshore Papua New Guinea. The site was investigated by multibeam and sidescan mapping, sub-bottom profiling, 2-D high-resolution multi-channel seismic reflection, and ROV video and coring operations. Numerous water column plumes were detected in the data suggesting vigorously active vents within and near the seafloor crater (Figure 1). This study uses dual-frequency MBES datasets (Reson 7125, 200/400 kHz) and ROV video imagery of the active hydrocarbon seeps to estimate total gas flux from the crater. Plumes of bubbles were extracted from the water column data using threshold filtering techniques. Analysis of video images of the seep emission sites within the crater provided estimates on bubble size, expulsion frequency, and ascent velocity. The average gas flux characteristics made from ROV video observations is extrapolated over the number

Mercury cycling in stream ecosystems. 1. Water column chemistry and transport

USGS Publications Warehouse

Brigham, M.E.; Wentz, D.A.; Aiken, G.R.; Krabbenhoft, D.P.

2009-01-01

We studied total mercury (THg) and methylmercury (MeHg) in eight streams, located in Oregon, Wisconsin, and Florida, that span large ranges in climate, landscape characteristics, atmospheric Hg deposition, and water chemistry. While atmospheric deposition was the source of Hg at each site, basin characteristics appeared to mediate this source by providing controls on methylation and fluvial THg and MeHg transport. Instantaneous concentrations of filtered total mercury (FTHg) and filtered methylmercury (FMeHg) exhibited strong positive correlations with both dissolved organic carbon (DOC) concentrations and streamflow for most streams, whereas mean FTHg and FMeHg concentrations were correlated with wetland density of the basins. For all streams combined, whole water concentrations (sum of filtered and particulate forms) of THg and MeHg correlated strongly with DOC and suspended sediment concentrations in the water column. ?? 2009 American Chemical Society.

Dispersal of post-larval macrobenthos in subtidal sedimentary habitats: Roles of vertical diel migration, water column, bedload transport and biological traits' expression

NASA Astrophysics Data System (ADS)

Pacheco, Aldo S.; Uribe, Roberto A.; Thiel, Martin; Oliva, Marcelo E.; Riascos, Jose M.

2013-03-01

Post-larval dispersal along the sediment-water interface is an important process in the dynamics of macrobenthic populations and communities in marine sublittoral sediments. However, the modes of post-larval dispersal in low energy sublittoral habitats have been poorly documented. Herein we examined the specific dispersal mechanisms (diel vertical migration, water column, and bedload transport) and corresponding biological traits of the dispersing assemblage. At two sublittoral sites (sheltered and exposed) along the northern coast of Chile, we installed different trap types that capture benthic organisms with specific modes of dispersal (active emergence and passive water column drifting) and also by a combination of mechanisms (bedload transport, passive suspension and settlement from the water column). Our results show that even though there were common species in all types of traps, the post-larval macrobenthic assemblage depended on specific mechanisms of dispersal. At the sheltered site, abundant emerging taxa colonized sediments that were placed 0.5 m above the bottom and bedload-transported invertebrates appeared to be associated to the passive drifting of macroalgae. At the exposed site, assemblage dispersal was driven by specific mechanisms e.g. bedload transport and active emergence. At both sites the biological traits "small size, swimming, hard exoskeleton, free living and surface position" were associated to water column and bedload dispersal. This study highlights the importance of (i) the water-sediment interface for dispersal of post-larvae in sublittoral soft-bottom habitat, and (ii) a specific set of biological traits when dispersing either along the bottom or through the water column.

Renal Cell Toxicity of Water-Soluble Coal Extracts from the Gulf Coast

NASA Astrophysics Data System (ADS)

Ojeda, A. S.; Ford, S.; Ihnat, M.; Gallucci, R. M.; Philp, P. R.

2017-12-01

In the Gulf Coast, many rural residents rely on private well water for drinking, cooking, and other domestic needs. A large portion of this region contains lignite coal deposits within shallow aquifers that potentially leach organic matter into the water supply. It is proposed that the organic matter leached from low-rank coal deposits contributes to the development of kidney disease, however, little work has been done to investigate the toxicity of coal extracts. In this study, human kidney cells (HK-2) were exposed to water-soluble extracts of Gulf Coast Coals to assess toxicity. Cell viability was measured by direct counts of total and necrotic cells. A dose-response curve was used to generate IC50 values, and the extracts showed significant toxicity that ranged from 0.5% w/v to 3% w/v IC50. The most toxic extract was from Louisiana where coal-derived organic material has been previously linked to high incidents of renal pelvic cancer (RPC). Although the toxic threshold measured in this study is significantly higher than the concentration of organic matter in the groundwater, typically <5 mg/L (0.005% w/v), residents in the affected areas may consume contaminated water over a lifetime. It is possible that the cumulative toxic effects of coal-derived material contribute to the development of disease.

Controlling factors of harmful microalgae distribution in water column, biofilm and sediment in shellfish production area (South of Sfax, Gulf of Gabes) from southern Tunisia

NASA Astrophysics Data System (ADS)

Loukil-Baklouti, Amira; Feki-Sahnoun, Wafa; Hamza, Asma; Abdennadher, Moufida; Mahfoudhi, Mabrouka; Bouain, Abderrahmen; Jarboui, Othman

2018-01-01

The aim of this study was to investigate the spatio-temporal distribution of harmful microalgae coupled with environmental factors in the most important area for natural stocks of the grooved carpet shell Ruditapes decussatus in southern Tunisia. Sampling was performed monthly from May 2010 to April 2011 in five stations through the Tunisian National Monitoring Stations Network of Phytoplankton and Phycotoxins along the southern coasts of Sfax (Gulf of Gabes). The presence of harmful microalgae species was explored in three compartments: water column, biofilm and sediment. Our results revealed fourteen species were identified belonging to dinoflagellates and diatoms with higher densities during the summer period. The co-inertia plot analysis exhibited that the seasonal fluctuations of these species were controlled by the temperature as well as the nutrients (particularly nitrogenous). Ternary diagrams showed that biofilm was the most colonized compartment by toxic benthic dinoflagellates species, namely Amphidinium carterae, Prorocentrum rathymum, Prorocentrum concavum, Prorocentrum lima, Ostreopsis cf. ovata and Coolia monotis. In addition, these species were recorded simultaneously in the water column and the sediment, a fact that could be explained by the resuspension of these benthic dinoflagellates from the biofilm by hydrodynamics. The data suggest that harmful microalgae could be the source of toxins in the studied stations, which provide support to the implication of these results on the future sampling strategy of harmful microalgae in shellfish collecting areas in Tunisia.

Sulfur speciation and sulfide oxidation in the water column of the Black Sea

NASA Astrophysics Data System (ADS)

Luther, George W., III; Church, Thomas M.; Powell, David

We have applied sulfur speciation techniques to understand the chemistry and cycling of sulfur in Black Sea waters. The only reduced dissolved inorganic sulfur species detected (above the low minimum detection limits of the voltammetric methods employed) in the water column was hydrogen sulfide. The maximum concentration of sulfide (423 μM) is similar to previous reports. Using a cathodic stripping square wave voltammetry (CSSWV) method for nanomolar levels of sulfide, we determined the precise boundary between the "free" hydrogen sulfide (sulfidic) zone and the upper (oxic/suboxic) water column at the two stations studied. This boundary has apparently moved up by about 50 m in the past 20 years. Our results help demonstrate three chemically distinct zones of water in the central basin of the Black Sea: (1) the oxic [0-65 m], (2) the anoxic/nonsulfidic [65-100 m] and (3) the sulfidic [>100 m]. Sulfide bound to metals ("complexed" sulfide) is observed in both the oxic and anoxic/nonsulfidic zones of the water column. This supports previous studies on metal sulfide forms. From the electrochemical data, it is possible to estimate the strength of the complexation of sulfide to metals (log K = 10 to 11). Thiosulfate and sulfite were below our minimum detectable limit (MDL) of 50 nM using CSSWV. Elemental sulfur (MDL 5 nM) was detected below the onset of the hydrogen sulfide zone (90-100 m) with a maximum of 30-60 nM near 120 m. The sulfur speciation results for the Black Sea are lower by one order of magnitude or more than other marine systems such as the Cariaco Trench and salt marshes. New HPLC techniques were applied to detect thiols at submicromolar levels. The presence of thiols (2-mercaptoethylamine, 2-mercaptoethanol, N-acetylcysteine and glutathione) is correlated with the remineralization of organic matter at the oxic and anoxic/nonsulfidic interface. Water samples collected from the upper 50 m of the sulfidic zone showed significant sulfide oxidation on

Undocumented water column sink for cadmium in open ocean oxygen-deficient zones

PubMed Central

Janssen, David J.; Conway, Tim M.; John, Seth G.; Christian, James R.; Kramer, Dennis I.; Pedersen, Tom F.; Cullen, Jay T.

2014-01-01

Cadmium (Cd) is a micronutrient and a tracer of biological productivity and circulation in the ocean. The correlation between dissolved Cd and the major algal nutrients in seawater has led to the use of Cd preserved in microfossils to constrain past ocean nutrient distributions. However, linking Cd to marine biological processes requires constraints on marine sources and sinks of Cd. Here, we show a decoupling between Cd and major nutrients within oxygen-deficient zones (ODZs) in both the Northeast Pacific and North Atlantic Oceans, which we attribute to Cd sulfide (CdS) precipitation in euxinic microenvironments around sinking biological particles. We find that dissolved Cd correlates well with dissolved phosphate in oxygenated waters, but is depleted compared with phosphate in ODZs. Additionally, suspended particles from the North Atlantic show high Cd content and light Cd stable isotope ratios within the ODZ, indicative of CdS precipitation. Globally, we calculate that CdS precipitation in ODZs is an important, and to our knowledge a previously undocumented marine sink of Cd. Our results suggest that water column oxygen depletion has a substantial impact on Cd biogeochemical cycling, impacting the global relationship between Cd and major nutrients and suggesting that Cd may be a previously unidentified tracer for water column oxygen deficiency on geological timescales. Similar depletions of copper and zinc in the Northeast Pacific indicate that sulfide precipitation in ODZs may also have an influence on the global distribution of other trace metals. PMID:24778239

Undocumented water column sink for cadmium in open ocean oxygen-deficient zones.

PubMed

Janssen, David J; Conway, Tim M; John, Seth G; Christian, James R; Kramer, Dennis I; Pedersen, Tom F; Cullen, Jay T

2014-05-13

Cadmium (Cd) is a micronutrient and a tracer of biological productivity and circulation in the ocean. The correlation between dissolved Cd and the major algal nutrients in seawater has led to the use of Cd preserved in microfossils to constrain past ocean nutrient distributions. However, linking Cd to marine biological processes requires constraints on marine sources and sinks of Cd. Here, we show a decoupling between Cd and major nutrients within oxygen-deficient zones (ODZs) in both the Northeast Pacific and North Atlantic Oceans, which we attribute to Cd sulfide (CdS) precipitation in euxinic microenvironments around sinking biological particles. We find that dissolved Cd correlates well with dissolved phosphate in oxygenated waters, but is depleted compared with phosphate in ODZs. Additionally, suspended particles from the North Atlantic show high Cd content and light Cd stable isotope ratios within the ODZ, indicative of CdS precipitation. Globally, we calculate that CdS precipitation in ODZs is an important, and to our knowledge a previously undocumented marine sink of Cd. Our results suggest that water column oxygen depletion has a substantial impact on Cd biogeochemical cycling, impacting the global relationship between Cd and major nutrients and suggesting that Cd may be a previously unidentified tracer for water column oxygen deficiency on geological timescales. Similar depletions of copper and zinc in the Northeast Pacific indicate that sulfide precipitation in ODZs may also have an influence on the global distribution of other trace metals.

Circulation, retention, and mixing of waters within the Weddell-Scotia Confluence, Southern Ocean: The role of stratified Taylor columns

NASA Astrophysics Data System (ADS)

Meredith, Michael P.; Meijers, Andrew S.; Naveira Garabato, Alberto C.; Brown, Peter J.; Venables, Hugh J.; Abrahamsen, E. Povl; Jullion, Loïc.; Messias, Marie-José

2015-01-01

The waters of the Weddell-Scotia Confluence (WSC) lie above the rugged topography of the South Scotia Ridge in the Southern Ocean. Meridional exchanges across the WSC transfer water and tracers between the Antarctic Circumpolar Current (ACC) to the north and the subpolar Weddell Gyre to the south. Here, we examine the role of topographic interactions in mediating these exchanges, and in modifying the waters transferred. A case study is presented using data from a free-drifting, intermediate-depth float, which circulated anticyclonically over Discovery Bank on the South Scotia Ridge for close to 4 years. Dimensional analysis indicates that the local conditions are conducive to the formation of Taylor columns. Contemporaneous ship-derived transient tracer data enable estimation of the rate of isopycnal mixing associated with this column, with values of O(1000 m2/s) obtained. Although necessarily coarse, this is of the same order as the rate of isopycnal mixing induced by transient mesoscale eddies within the ACC. A picture emerges of the Taylor column acting as a slow, steady blender, retaining the waters in the vicinity of the WSC for lengthy periods during which they can be subject to significant modification. A full regional float data set, bathymetric data, and a Southern Ocean state estimate are used to identify other potential sites for Taylor column formation. We find that they are likely to be sufficiently widespread to exert a significant influence on water mass modification and meridional fluxes across the southern edge of the ACC in this sector of the Southern Ocean.

A microwave satellite water vapour column retrieval for polar winter conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Perro, Christopher; Lesins, Glen; Duck, Thomas J.

A new microwave satellite water vapour retrieval for the polar winter atmosphere is presented. The retrieval builds on the work of Miao et al. (2001) and Melsheimer and Heygster (2008), employing auxiliary information for atmospheric conditions and numerical optimization. It was tested using simulated and actual measurements from the Microwave Humidity Sounder (MHS) satellite instruments. Ground truth was provided by the G-band vapour radiometer (GVR) at Barrow, Alaska. For water vapour columns less than 6 kg m -2, comparisons between the retrieval and GVR result in a root mean square (RMS) deviation of 0.39 kg m -2 and a systematic bias of 0.08 kg m -2. These results aremore » compared with RMS deviations and biases at Barrow for the retrieval of Melsheimer and Heygster (2008), the AIRS and MIRS satellite data products, and the ERA-Interim, NCEP, JRA-55, and ASR reanalyses. When applied to MHS measurements, the new retrieval produces a smaller RMS deviation and bias than for the earlier retrieval and satellite data products. The RMS deviations for the new retrieval were comparable to those for the ERA-Interim, JRA-55, and ASR reanalyses; however, the MHS retrievals have much finer horizontal resolution (15 km at nadir) and reveal more structure. The new retrieval can be used to obtain pan-Arctic maps of water vapour columns of unprecedented quality. It may also be applied to measurements from the Special Sensor Microwave/Temperature 2 (SSM/T2), Advanced Microwave Sounding Unit B (AMSU-B), Special Sensor Microwave Imager/Sounder (SSMIS), Advanced Technology Microwave Sounder (ATMS), and Chinese MicroWave Humidity Sounder (MWHS) instruments.« less

Responses of Water and Salt Parameters to Groundwater Levels for Soil Columns Planted with Tamarix chinensis

PubMed Central

Xia, Jiangbao; Zhao, Ximei; Chen, Yinping; Fang, Ying; Zhao, Ziguo

2016-01-01

Groundwater is the main water resource for plant growth and development in the saline soil of the Yellow River Delta in China. To investigate the variabilities and distributions of soil water and salt contents at various groundwater level (GL), soil columns with planting Tamarix chinensis Lour were established at six different GL. The results demonstrated the following: With increasing GL, the relative soil water content (RWC) declined significantly, whereas the salt content (SC) and absolute soil solution concentration (CS) decreased after the initial increase in the different soil profiles. A GL of 1.2 m was the turning point for variations in the soil water and salt contents, and it represented the highest GL that could maintain the soil surface moist within the soil columns. Both the SC and CS reached the maximum levels in these different soil profiles at a GL of 1.2 m. With the raise of soil depth, the RWC increased significantly, whereas the SC increased after an initial decrease. The mean SC values reached 0.96% in the top soil layer; however, the rates at which the CS and RWC decreased with the GL were significantly reduced. The RWC and SC presented the greatest variations at the medium (0.9–1.2 m) and shallow water levels (0.6 m) respectively, whereas the CS presented the greatest variation at the deep water level (1.5–1.8 m).The RWC, SC and CS in the soil columns were all closely related to the GL. However, the correlations among the parameters varied greatly within different soil profiles, and the most accurate predictions of the GL were derived from the RWC in the shallow soil layer or the SC in the top soil layer. A GL at 1.5–1.8 m was moderate for planting T. chinensis seedlings under saline groundwater conditions. PMID:26730602

Comparison of Passive Samplers for Monitoring Dissolved Organic Contaminants in Water Column Deployments (SETAC Europe 22nd Annual Meeting)

EPA Science Inventory

Nonionic organic contaminants (NOCs) are difficult to measure in the water column due to their inherent chemical properties resulting in low water solubility and high particle activity. Traditional sampling methods require large quantities of water to be extracted and interferen...

Bivalve embryo bioassay to assess the potential toxicity of dredged material before dumping

DOE Office of Scientific and Technical Information (OSTI.GOV)

Quiniou, F.

1995-12-31

Dredged harbor sediments frequently contain a wide spectrum of contaminants in addition to a significant percentage of organic matter. Also, dredging and dumping activities into sea water, of these highly contaminated soil may induce a harmful effect on the environment. In France, in accordance with Oslo convention guidelines, a working group on dredging activities and environment (GEODE) created since 1991 decided to set up a pilot research program to assess the intrinsic toxicity of four harbor sludges. Intrinsic toxicity of harbor muds were tested by solid phase (whole sediment) and aqueous extract bioassays (sea water elutriates) using the sublethal toxicitymore » test bivalve embryo bioassay (Crassostrea gigas). Elutriates enable them to detect the toxicity of contaminants which may be released in the soluble form into the water column during dredging operations. While, whole sediment integrate the synergistic effects of all the contaminants (hydrophilic and hydrophobic) including pore water. Bioassays results, correlated to chemical analysis, are compared to contaminant levels determined by French working group GEODE and Canadian sediment quality criteria.« less

Prediction of E. coli release from streambed to water column during base flow periods using SWAT model

USDA-ARS?s Scientific Manuscript database

Microbial water quality in streams is of importance for recreation, irrigation, and other uses. The streambed sediment has been shown to harbor large fecal indicator bacteria (FIB) population that can be released to water column during high-flow events when sediments are resuspended. There have been...

Properties of the water column and bottom derived from Airborne Visible Infrared Imaging Spectrometer (AVIRIS) data

NASA Astrophysics Data System (ADS)

Lee, Zhongping; Carder, Kendall L.; Chen, Robert F.; Peacock, Thomas G.

2001-06-01

Using Airborne Visible Infrared Imaging Spectrometer (AVIRIS) data as an example, we show in this study that the properties of the water column and bottom of a large, shallow area can be adequately retrieved using a model-driven optimization technique. The simultaneously derived properties include bottom depth, bottom albedo, and water absorption and backscattering coefficients, which in turn could be used to derive concentrations of chlorophyll, dissolved organic matter, and suspended sediments in the water column. The derived bottom depths were compared with a bathymetry chart and a boat survey and were found to agree very well. Also, the derived bottom albedo image shows clear spatial patterns, with end-members consistent with sand and seagrass. The image of absorption and backscattering coefficients indicates that the water is quite horizontally mixed. Without bottom corrections, chlorophyll a retrievals were ˜50 mg m-3, while the retrievals after bottom corrections were tenfold less, approximating real values. These results suggest that the model and approach used work very well for the retrieval of subsurface properties of shallow-water environments even for rather turbid environments like Tampa Bay, Florida.

A compendium of geochemical information from the Saanich Inlet water column

NASA Astrophysics Data System (ADS)

Torres-Beltrán, Mónica; Hawley, Alyse K.; Capelle, David; Zaikova, Elena; Walsh, David A.; Mueller, Andreas; Scofield, Melanie; Payne, Chris; Pakhomova, Larysa; Kheirandish, Sam; Finke, Jan; Bhatia, Maya; Shevchuk, Olena; Gies, Esther A.; Fairley, Diane; Michiels, Céline; Suttle, Curtis A.; Whitney, Frank; Crowe, Sean A.; Tortell, Philippe D.; Hallam, Steven J.

2017-10-01

Extensive and expanding oxygen minimum zones (OMZs) exist at variable depths in coastal and open ocean waters. As oxygen levels decline, nutrients and energy are increasingly diverted away from higher trophic levels into microbial community metabolism, resulting in fixed nitrogen loss and production of climate active trace gases including nitrous oxide and methane. While ocean deoxygenation has been reported on a global scale, our understanding of OMZ biology and geochemistry is limited by a lack of time-resolved data sets. Here, we present a historical dataset of oxygen concentrations spanning fifty years and nine years of monthly geochemical time series observations in Saanich Inlet, a seasonally anoxic fjord on the coast of Vancouver Island, British Columbia, Canada that undergoes recurring changes in water column oxygenation status. This compendium provides a unique geochemical framework for evaluating long-term trends in biogeochemical cycling in OMZ waters.

Aerobic and anaerobic degradation and mineralization of 14C-chitin by water column and sediment inocula of the York River estuary, Virginia.

PubMed Central

Boyer, J N

1994-01-01

Potential rates of chitin degradation (Cd) and mineralization (Cm) by estuarine water and sediment bacteria were measured as a function of inoculum source, temperature, and oxygen condition. In the water column inoculum, 88 to 93% of the particulate chitin was mineralized to CO2 with no apparent lag between degradation and mineralization. No measurable dissolved pool of radiolabel was found in the water column. For the sediment inocula, 70 to 90% of the chitin was degraded while only 55 to 65% was mineralized to CO2. 14C label recoveries in the dissolved pool were 19 to 21% for sand, 17 to 24% in aerobic mud, and 12 to 21% for the anaerobic mud. This uncoupling between degradation and mineralization occurred in all sediment inocula. More than 98% of the initial 14C-chitin was recovered in the three measured fractions. The highest Cd and Cm values, 30 and 27% day-1, occurred in the water column inoculum at 25 degrees C. The lowest Cd and Cm values were found in the aerobic and anaerobic mud inocula incubated at 15 degrees C. Significant differences in Cd and Cm values among water column and sediment inocula as well as between temperature treatments were evident. An increased incubation temperature resulted in shorter lag times before the onset of chitinoclastic bacterial growth, degradation, and mineralization and resulted in apparent Q10 values of 1.1 for water and 1.3 to 2.1 for sediment inocula. It is clear that chitin degradation and mineralization occur rapidly in the estuary and that water column bacteria may be more important in this process than previously acknowledged. PMID:8117075

Ecological impacts of lead mining on Ozark streams: toxicity of sediment and pore water.

PubMed

Besser, John M; Brumbaugh, William G; Allert, Ann L; Poulton, Barry C; Schmitt, Christopher J; Ingersoll, Christopher G

2009-02-01

We studied the toxicity of sediments downstream of lead-zinc mining areas in southeast Missouri, using chronic sediment toxicity tests with the amphipod, Hyalella azteca, and pore-water toxicity tests with the daphnid, Ceriodaphnia dubia. Tests conducted in 2002 documented reduced survival of amphipods in stream sediments collected near mining areas and reduced survival and reproduction of daphnids in most pore waters tested. Additional amphipod tests conducted in 2004 documented significant toxic effects of sediments from three streams downstream of mining areas: Strother Creek, West Fork Black River, and Bee Fork. Greatest toxicity occurred in sediments from a 6-km reach of upper Strother Creek, but significant toxic effects occurred in sediments collected at least 14 km downstream of mining in all three watersheds. Toxic effects were significantly correlated with metal concentrations (nickel, zinc, cadmium, and lead) in sediments and pore waters and were generally consistent with predictions of metal toxicity risks based on sediment quality guidelines, although ammonia and manganese may also have contributed to toxicity at a few sites. Responses of amphipods in sediment toxicity tests were significantly correlated with characteristics of benthic invertebrate communities in study streams. These results indicate that toxicity of metals associated with sediments contributes to adverse ecological effects in streams draining the Viburnum Trend mining district.

Ecological impacts of lead mining on Ozark streams: Toxicity of sediment and pore water

USGS Publications Warehouse

Besser, J.M.; Brumbaugh, W.G.; Allert, A.L.; Poulton, B.C.; Schmitt, C.J.; Ingersoll, C.G.

2009-01-01

We studied the toxicity of sediments downstream of lead-zinc mining areas in southeast Missouri, using chronic sediment toxicity tests with the amphipod, Hyalella azteca, and pore-water toxicity tests with the daphnid, Ceriodaphnia dubia. Tests conducted in 2002 documented reduced survival of amphipods in stream sediments collected near mining areas and reduced survival and reproduction of daphnids in most pore waters tested. Additional amphipod tests conducted in 2004 documented significant toxic effects of sediments from three streams downstream of mining areas: Strother Creek, West Fork Black River, and Bee Fork. Greatest toxicity occurred in sediments from a 6-km reach of upper Strother Creek, but significant toxic effects occurred in sediments collected at least 14 km downstream of mining in all three watersheds. Toxic effects were significantly correlated with metal concentrations (nickel, zinc, cadmium, and lead) in sediments and pore waters and were generally consistent with predictions of metal toxicity risks based on sediment quality guidelines, although ammonia and manganese may also have contributed to toxicity at a few sites. Responses of amphipods in sediment toxicity tests were significantly correlated with characteristics of benthic invertebrate communities in study streams. These results indicate that toxicity of metals associated with sediments contributes to adverse ecological effects in streams draining the Viburnum Trend mining district.

Toxic pressure of herbicides on microalgae in Dutch estuarine and coastal waters

NASA Astrophysics Data System (ADS)

Booij, Petra; Sjollema, Sascha B.; van der Geest, Harm G.; Leonards, Pim E. G.; Lamoree, Marja H.; de Voogt, W. Pim; Admiraal, Wim; Laane, Remi W. P. M.; Vethaak, A. Dick

2015-08-01

For several decades now, there has been an increase in the sources and types of chemicals in estuarine and coastal waters as a consequence of anthropogenic activities. This has led to considerable concern about the effects of these chemicals on the marine food chain. The fact is that estuarine and coastal waters are the most productive ecosystems with high primary production by microalgae. The toxic pressure of specific phytotoxic chemicals now poses a major threat to these ecosystems. In a previous study, six herbicides (atrazine, diuron, irgarol, isoproturon, terbutryn and terbutylazine) were identified as the main contaminants affecting photosynthesis in marine microalgae. The purpose of this study is to investigate the toxic pressure of these herbicides in the Dutch estuarine and coastal waters in relation to the effective photosystem II efficiency (ΦPSII) in microalgae. Temporal and spatial variations in the concentrations of these herbicides were analyzed based on monitoring data. Additionally, a field study was carried out in which chemical analysis of water was performed and also a toxicity assessment using the Pulse Amplitude Modulation (PAM) fluorometry assay that measures ΦPSII. The toxic pressure on ΦPSII in microalgae has decreased with 55-82% from 2003 to 2012, with the Western Scheldt estuary showing the highest toxic pressure. By combining toxicity data from the PAM assay with chemical analysis of herbicide concentrations, we have identified diuron and terbutylazine as the main contributors to the toxic pressure on microalgae. Although direct effects are not expected, the toxic pressure is close to the 10% effect level in the PAM assay. A compliance check with the current environmental legislation of the European Union revealed that the quality standards are not sufficient to protect marine microalgae.

Comparison of a novel passive sampler to standard water-column sampling for organic contaminants associated with wastewater effluents entering a New Jersey stream

USGS Publications Warehouse

Alvarez, D.A.; Stackelberg, P.E.; Petty, J.D.; Huckins, J.N.; Furlong, E.T.; Zaugg, S.D.; Meyer, M.T.

2005-01-01

Four water samples collected using standard depth and width water-column sampling methodology were compared to an innovative passive, in situ, sampler (the polar organic chemical integrative sampler or POCIS) for the detection of 96 organic wastewater-related contaminants (OWCs) in a stream that receives agricultural, municipal, and industrial wastewaters. Thirty-two OWCs were identified in POCIS extracts whereas 9-24 were identified in individual water-column samples demonstrating the utility of POCIS for identifying contaminants whose occurrence are transient or whose concentrations are below routine analytical detection limits. Overall, 10 OWCs were identified exclusively in the POCIS extracts and only six solely identified in the water-column samples, however, repetitive water samples taken using the standard method during the POCIS deployment period required multiple trips to the sampling site and an increased number of samples to store, process, and analyze. Due to the greater number of OWCs detected in the POCIS extracts as compared to individual water-column samples, the ease of performing a single deployment as compared to collecting and processing multiple water samples, the greater mass of chemical residues sequestered, and the ability to detect chemicals which dissipate quickly, the passive sampling technique offers an efficient and effective alternative for detecting OWCs in our waterways for wastewater contaminants.

Fixed bed column study for water defluoridation using neem oil-phenolic resin treated plant bio-sorbent.

PubMed

Manna, Suvendu; Saha, Prosenjit; Roy, Debasis; Adhikari, Basudam; Das, Papita

2018-04-15

Fluoride has both detrimental and beneficial effects on living beings depending on the concentration and consumption periods. The study presented in this article investigated the feasibility of using neem oil phenolic resin treated lignocellulosic bio-sorbents for fluoride removal from water through fixed bed column study. Results indicated that treated bio-sorbents could remove fluoride both from synthetic and groundwater with variable bed depth, flow rate, fluoride concentration and column diameter. Data obtained from this study indicated that columns with the thickest bed, lowest flow rate, and fluoride concentration showed best column performance. Bio-sorbents used in this study are regenerable and reusable for more than five cycles. The initial materials cost needed to remove one gram of fluoride also found to be lower than the available alternatives. This makes the process more promising candidate to be used for fluoride removal. In addition, the process is also technically advantageous over the available alternatives. Copyright © 2018 Elsevier Ltd. All rights reserved.

Bioelectrochemical biosensor for water toxicity detection: generation of dual signals for electrochemical assay confirmation.

PubMed

Yang, Yuan; Wang, Yan-Zhai; Fang, Zhen; Yu, Yang-Yang; Yong, Yang-Chun

2018-02-01

Toxicity assessment of water is of great important to the safety of human health and to social security because of more and more toxic compounds that are spilled into the aquatic environment. Therefore, the development of fast and reliable toxicity assessment methods is of great interest and attracts much attention. In this study, by using the electrochemical activity of Shewanella oneidensis MR-1 cells as the toxicity indicator, 3,5-dichlorophenol (DCP) as the model toxic compound, a new biosensor for water toxicity assessment was developed. Strikingly, the presence of DCP in the water significantly inhibited the maximum current output of the S. oneidensis MR-1 in a three-electrode system and also retarded the current evolution by the cells. Under the optimized conditions, the maximum current output of the biosensor was proportional to the concentration of DCP up to 30 mg/L. The half maximal inhibitory concentration of DCP determined by this biosensor is about 14.5 mg/L. Furthermore, simultaneous monitoring of the retarded time (Δt) for current generation allowed the identification of another biosensor signal in response to DCP which could be employed to verify the electrochemical result by dual confirmation. Thus, the present study has provided a reliable and promising approach for water quality assessment and risk warning of water toxicity.

Small Microbial Three-Electrode Cell Based Biosensor for Online Detection of Acute Water Toxicity.

PubMed

Yu, Dengbin; Zhai, Junfeng; Liu, Changyu; Zhang, Xueping; Bai, Lu; Wang, Yizhe; Dong, Shaojun

2017-11-22

The monitoring of toxicity of water is very important to estimate the safety of drinking water and the level of water pollution. Herein, a small microbial three-electrode cell (M3C) biosensor filled with polystyrene particles was proposed for online monitoring of the acute water toxicity. The peak current of the biosensor related with the performance of the bioanode was regarded as the toxicity indicator, and thus the acute water toxicity could be determined in terms of inhibition ratio by comparing the peak current obtained with water sample to that obtained with nontoxic standard water. The incorporation of polystyrene particles in the electrochemical cell not only reduced the volume of the samples used, but also improved the sensitivity of the biosensor. Experimental conditions including washing time with PBS and the concentration of sodium acetate solution were optimized. The stability of the M3C biosensor under optimal conditions was also investigated. The M3C biosensor was further examined by formaldehyde at the concentration of 0.01%, 0.03%, and 0.05% (v/v), and the corresponding inhibition ratios were 14.6%, 21.6%, and 36.4%, respectively. This work provides a new insight into the development of an online toxicity detector based on M3C biosensor.

Life Under the Ice: Spatial and Temporal Patterns in Rates of Water Column and Sediment Respiration in 5 Alaskan Arctic Lakes

NASA Astrophysics Data System (ADS)

Sadro, S.; MacIntyre, S.

2014-12-01

Alaskan arctic lakes lay covered by up to three meters of ice and snow for approximately two-thirds of the year, yet comparatively little is known about their ecosystem metabolism during this period. We combined the use of free-water measurements of dissolved oxygen (DO) and the laboratory incubation of sediment cores to characterize spatial and temporal patterns in the ecosystem respiration (ER) of five arctic lakes spanning a gradient in size from 1 to 150 ha. Seasonal rates of ER throughout the water column ranged from < 0.001 to 0.034 mg L-1 h-1; sediment ER ranged from mg 6.1 m-2 h-1 to 50.7 mg m-2 h-1. Although there were significant differences in sediment ER among lakes, average water column ER did not differ significantly. Seasonal patterns of DO draw down were most often linear. However, within the water column above the deepest basin of each lake, rates were higher during autumn - winter than winter - spring, with the lowest rates typically found in the upper 70% of the water column and the highest rates near the bottom. ER measured near the bottom along the slope of lake basins was lower than that at the center of lake basins and closer in magnitude to water column ER. Spatial patters in free-water rates were reflected by sediment ER, which was 21 - 66 % higher in cores collected from the deepest point of lake basins than in sediments collected at shallower locations found at the margin of basins. These observations suggest that two mechanisms operating in tandem account for the higher apparent rates of DO drawdown found within lake basins during the winter. Higher local rates of sediment ER and, similar to observations in other lakes, the transport of DO depleted waters from lake margins to deep basins. Together they contribute to the formation of hypoxia in the deeper basins of lakes and the concentration of other respiratory products, with important implications for energy flow within lakes and carbon budgets across the arctic.

Phytoremediation of wastewater toxicity using water hyacinth (Eichhornia crassipes) and water lettuce (Pistia stratiotes).

PubMed

Victor, Kouamé Kouamé; Séka, Yapoga; Norbert, Kouadio Kouakou; Sanogo, Tidou Abiba; Celestin, Atsé Boua

2016-10-02

This paper elucidates the phytoremediation potential of water hyacinth and water lettuce on the reduction of wastewater toxicity. Acute toxicity tests were performed in an aquarium with a population of Sarotherodon melanotheron, contaminated by different concentrations of wastewaters before and after phytoremediation with Eichhornia crassipes and Pistia stratiotes. Lethal concentrations (LC50) of the fish's population obtained during 24 hours of exposures were determined. COD, BOD, ammonium, TKN and PO4(3-) concentrations in wastewaters were of 1850.29, 973.33, 38.34, 61.49 and 39.23 mg L(-1), respectively, for each plant. Phytoremediation reduced 58.87% of ammonium content, 50.04% of PO4(3-), 82.45% of COD and 84.91% of BOD. After 15 days of the experiment, metal contents in treated wastewaters decreased from 6.65 to 97.56% for water hyacinth and 3.51 to 93.51% for water lettuce tanks. Toxicity tests showed that the mortality of fish exposed increased with increase in concentration of pollutants in wastewaters and the time of exposure. Therefore, the highest value of LC50 was recorded for fish subjected to 3 hours of exposure (16.37%). The lowest rate was obtained after an exposure of 20 to 24 hours (5.85%). After phytoremediation, the effluents purified by Eichhornia crassipes can maintain the fish life beyond 24 hours of exposure.

Reduction of hydraulic conductivity in column simulations of unconsolidated sediments by growth of in situ microflora

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bertetti, F.P.; Birnbaum, S.J.

1992-01-01

Laboratory experiments were employed to determine the effects of microbial growth upon the hydraulic conductivity (K) of unconsolidated sediments at Kelly Air Force Base, Texas. Indigenous microflora were isolated from sediment samples collected at sites contaminated with toxic organic compounds (e.g. dichlorobenzene) by plating on concentrated and dilute media. Plexiglas columns were packed with silica beads or Kelly AFB sediment and used to simulate ground water flow conditions. Grain sizes were selected to yield realistic K values (2.0 [times] 10[sup [minus]1] to 8.0 [times] 10[sup [minus]3] cm/sec) defined by field data from the contaminated sites. Both individual and mixed microbialmore » colonies, selected based on morphological characteristics individual and mixed microbial colonies, selected based on morphological characteristics deemed favorable for porosity obstruction, were injected into sterile, saturated columns. Growth was stimulated by adding sterile liquid nutrient media. Media flow rates were based upon field derived hydraulic conductivity values and water table gradients. Flow rates were controlled using a peristaltic pump. Growth of the microorganisms produced biomass which reduced the column hydraulic conductivity by up to 90% in 11 days. Reduction in K was accomplished via clogging of pore throats by cell attachment and accumulation on bead surfaces, and extracellular biofilm development. Sediment packed columns showed reduction in K values similar to that of bead packed columns of equivalent grain size. Porosity obstruction and corresponding reduction in K persisted in the columns even when subjected to hydraulic gradients significantly exceeding gradients measured in the field thereby demonstrating the robust nature of biological barrier to flow.« less

Occurrence and Comparative Toxicity of Haloacetaldehyde Disinfection Byproducts in Drinking Water.

PubMed

Jeong, Clara H; Postigo, Cristina; Richardson, Susan D; Simmons, Jane Ellen; Kimura, Susana Y; Mariñas, Benito J; Barcelo, Damia; Liang, Pei; Wagner, Elizabeth D; Plewa, Michael J

2015-12-01

The introduction of drinking water disinfection greatly reduced waterborne diseases. However, the reaction between disinfectants and natural organic matter in the source water leads to an unintended consequence, the formation of drinking water disinfection byproducts (DBPs). The haloacetaldehydes (HALs) are the third largest group by weight of identified DBPs in drinking water. The primary objective of this study was to analyze the occurrence and comparative toxicity of the emerging HAL DBPs. A new HAL DBP, iodoacetaldehyde (IAL) was identified. This study provided the first systematic, quantitative comparison of HAL toxicity in Chinese hamster ovary cells. The rank order of HAL cytotoxicity is tribromoacetaldehyde (TBAL) ≈ chloroacetaldehyde (CAL) > dibromoacetaldehyde (DBAL) ≈ bromochloroacetaldehyde (BCAL) ≈ dibromochloroacetaldehyde (DBCAL) > IAL > bromoacetaldehyde (BAL) ≈ bromodichloroacetaldehyde (BDCAL) > dichloroacetaldehyde (DCAL) > trichloroacetaldehyde (TCAL). The HALs were highly cytotoxic compared to other DBP chemical classes. The rank order of HAL genotoxicity is DBAL > CAL ≈ DBCAL > TBAL ≈ BAL > BDCAL>BCAL ≈ DCAL>IAL. TCAL was not genotoxic. Because of their toxicity and abundance, further research is needed to investigate their mode of action to protect the public health and the environment.

A global ocean inventory of anthropogenic mercury based on water column measurements.

PubMed

Lamborg, Carl H; Hammerschmidt, Chad R; Bowman, Katlin L; Swarr, Gretchen J; Munson, Kathleen M; Ohnemus, Daniel C; Lam, Phoebe J; Heimbürger, Lars-Eric; Rijkenberg, Micha J A; Saito, Mak A

2014-08-07

Mercury is a toxic, bioaccumulating trace metal whose emissions to the environment have increased significantly as a result of anthropogenic activities such as mining and fossil fuel combustion. Several recent models have estimated that these emissions have increased the oceanic mercury inventory by 36-1,313 million moles since the 1500s. Such predictions have remained largely untested owing to a lack of appropriate historical data and natural archives. Here we report oceanographic measurements of total dissolved mercury and related parameters from several recent expeditions to the Atlantic, Pacific, Southern and Arctic oceans. We find that deep North Atlantic waters and most intermediate waters are anomalously enriched in mercury relative to the deep waters of the South Atlantic, Southern and Pacific oceans, probably as a result of the incorporation of anthropogenic mercury. We estimate the total amount of anthropogenic mercury present in the global ocean to be 290 ± 80 million moles, with almost two-thirds residing in water shallower than a thousand metres. Our findings suggest that anthropogenic perturbations to the global mercury cycle have led to an approximately 150 per cent increase in the amount of mercury in thermocline waters and have tripled the mercury content of surface waters compared to pre-anthropogenic conditions. This information may aid our understanding of the processes and the depths at which inorganic mercury species are converted into toxic methyl mercury and subsequently bioaccumulated in marine food webs.

Quantifying the Benthic Source of Nutrients to the Water Column of Upper Klamath Lake, Oregon

USGS Publications Warehouse

Kuwabara, James S.; Lynch, Dennis D.; Topping, Brent R.; Murphy, Fred; Carter, James L.; Simon, Nancy S.; Parcheso, Francis; Wood, Tamara M.; Lindenberg, Mary K.; Wiese, Katryn; Avanzino, Ronald J.

2007-01-01

Executive Summary Five sampling trips were coordinated in April, May and August 2006, and May and July 2007 to sample the water column and benthos of Upper Klamath Lake, OR (Fig. 1; Table 1), before, during and after the annual cyanophyte bloom of Aphanizomenon flos-aquae (AFA). A pore-water profiler was designed and fabricated to obtain the first high-resolution (centimeter-scale) estimates of the vertical concentration gradients for diffusive-flux determinations. Estimates based on molecular diffusion may underestimate benthic flux because solute transport across the sediment-water interface can be enhanced by processes including bioturbation, bioirrigation and ground-water advection. Water-column and benthic samples were also collected to help interpret spatial and temporal trends in diffusive-flux estimates. Data from these samples complement geochemical analyses of bottom-sediments taken from Upper Klamath Lake (UKL) in 2005. This ongoing study provides information necessary for developing process-interdependent solute-transport models for the watershed (that is, models integrating physical, geochemical and biological processes), and supports efforts to evaluate remediation or load-allocation strategies. To augment studies funded by the U.S. Bureau of Reclamation (USBR), the Department of Interior supported an additional full deployment of pore-water profilers in July 2007, during the summer AFA bloom. Results from this recent field trip are not fully completed. Data not presented herein will be included in a subsequent publication, scheduled for March 2009.

Selection of a battery of rapid toxicity sensors for drinking water evaluation.

PubMed

van der Schalie, William H; James, Ryan R; Gargan, Thomas P

2006-07-15

Comprehensive identification of chemical contaminants in Army field water supplies can be a lengthy process, but rapid analytical methods suitable for field use are limited. A complementary approach is to directly measure toxicity instead of individual chemical constituents. Ten toxicity sensors utilizing enzymes, bacteria, or vertebrate cells were tested to determine the minimum number of sensors that could rapidly identify toxicity in water samples containing one of 12 industrial chemicals. The ideal sensor would respond at a concentration just exceeding the Military Exposure Guideline (MEG) level for the chemical (an estimated threshold for adverse effects) but below the human lethal concentration. Chemical solutions were provided to testing laboratories as blind samples. No sensors responded to deionized water blanks, and only one sensor responded to a hard water blank. No single toxicity sensor responded to more than six chemicals in the desired response range, and one chemical (nicotine) was not detected by any sensor with the desired sensitivity. A combination of three sensors (Microtox, the Electric Cell Substrate Impedance Sensing (ECIS) test, and the Hepatocyte low density lipoprotein (LDL) uptake test) responded appropriately to nine of twelve chemicals. Adding a fourth sensor (neuronal microelectrode array) to the test battery allowed detection of two additional chemicals (aldicarb and methamidophos), but the neuronal microelectrode array was overly sensitive to paraquat. Evaluating sensor performance using a standard set of chemicals and a desired sensitivity range provides a basis both for selecting among available toxicity sensors and for evaluating emerging sensor technologies. Recommendations for future toxicity sensor evaluations are discussed.

Determination of physical and dynamic properties of suspended particles in water column with ultrasonic scanning in between the water surface and stable sediment layer.

NASA Astrophysics Data System (ADS)

Acar, Dursun; Alpar, Bedri; Ozeren, Sinan; Cagatay, Namık; Sari, Erol; Vardar, Denizhan; Eris, Kadir

2015-04-01

The behavior of seafloor sediment with its water column should be known against any occurrences of anoxic or oxic conditions. The most important ones of these conditions are possible leakage of natural gas or escape of liquids from sediment. On the basis of combined solid/liquid flow dynamics in sedimentation, such kind of events can change, even in an effective manner, the dynamic movements of molecules and their cumulative mass of particules, i.e. the suspended materials. The deployment of suitable sediment traps or ultrasonic transducers somewhere in the water column are not easy attempts in order to obtain useful information about the state of suspended materials during sedimentation. These are usually bulky instruments; therefore they may behave like an anti-move suppresser on the particles moving in the float direction, in oxic and anoxic manner. These instruments, on the other hand, may cover the effects of diffusive flow or bubble formed gas and fluid escape from the sediment surface into the water column. Ultrasonic scanners, however, are able to make observations in a remote manner, without affecting such artificial events. Our field trials were successfully completed at the historical estuary called Halic of Marmara sea . The physical properties; such as the velocity of particles, their travel directions, their dimensions and the ability to observe anti-compositor crushes of shock waves of the bubbles are only a few of these observations in natural ambience. The most important problem solved about water pressure during 3 atmosphere . The sensor has been tested successfully few times. We used the ''High voltage electric isolator oil filling'' to the inside of the scanner for pressure equalization between outer side and inner body of probe at a depth of (20 meters) beneath the sea surface . The transmitted signals by the planar crystal of the transducer become weaker under the pressure of overlying water column in depths. Our efforts are now focused on the

Bioremoval of heavy metals from industrial effluent by fixed-bed column of red macroalgae.

PubMed

Ibrahim, Wael M; Mutawie, Hawazin H

2013-02-01

Three different species of nonliving red algal biomass Laurancia obtusa, Geldiella acerosa and Hypnea sp. were used to build three types of fixed-bed column for the removal of toxic heavy metal ions such as Cu(2+), Zn(2+), Mn(2+) and Ni(2+) from industrial effluent. In general, the highest efficiency of metal ion bioremoval was recorded for algal column of L. obtusa followed by G. acerosa and the lowest one was recorded for Hypnea sp., with mean removal values of 94%, 85% and 71%, respectively. The obtained results showed that biological treatments of industrial effluents with these algal columns, using standard algal biotest, Pseudokirchneriella subcapitata, were capable of reducing effluent toxicities from 75% to 15%, respectively. Red algal column may be considered as an inexpensive and efficient alternative treatment for conventional removal technology, for sequestering heavy metal ions from industrial effluents.

Impacts of short-time scale water column variability on broadband high-frequency acoustic wave propagation

NASA Astrophysics Data System (ADS)

Eickmeier, Justin

Acoustical oceanography is one way to study the ocean, its internal layers, boundaries and all processes occurring within using underwater acoustics. Acoustical sensing techniques allows for the measurement of ocean processes from within that logistically or financially preclude traditional in-situ measurements. Acoustic signals propagate as pressure wavefronts from a source to a receiver through an ocean medium with variable physical parameters. The water column physical parameters that change acoustic wave propagation in the ocean include temperature, salinity, current, surface roughness, seafloor bathymetry, and vertical stratification over variable time scales. The impacts of short-time scale water column variability on acoustic wave propagation include coherent and incoherent surface reflections, wavefront arrival time delay, focusing or defocusing of the intensity of acoustic beams and refraction of acoustic rays. This study focuses on high-frequency broadband acoustic waves, and examines the influence of short-time scale water column variability on broadband high-frequency acoustics, wavefronts, from 7 to 28 kHz, in shallow water. Short-time scale variability is on the order of seconds to hours and the short-spatial scale variability is on the order of few centimeters. Experimental results were collected during an acoustic experiment along 100 m isobaths and data analysis was conducted using available acoustic wave propagation models. Three main topics are studied to show that acoustic waves are viable as a remote sensing tool to measure oceanographic parameters in shallow water. First, coherent surface reflections forming striation patterns, from multipath receptions, through rough surface interaction of broadband acoustic signals with the dynamic sea surface are analyzed. Matched filtered results of received acoustic waves are compared with a ray tracing numerical model using a sea surface boundary generated from measured water wave spectra at the time of

Heterotrophic Protists in Hypersaline Microbial Mats and Deep Hypersaline Basin Water Columns

PubMed Central

Edgcomb, Virginia P.; Bernhard, Joan M.

2013-01-01

Although hypersaline environments pose challenges to life because of the low water content (water activity), many such habitats appear to support eukaryotic microbes. This contribution presents brief reviews of our current knowledge on eukaryotes of water-column haloclines and brines from Deep Hypersaline Anoxic Basins (DHABs) of the Eastern Mediterranean, as well as shallow-water hypersaline microbial mats in solar salterns of Guerrero Negro, Mexico and benthic microbialite communities from Hamelin Pool, Shark Bay, Western Australia. New data on eukaryotic diversity from Shark Bay microbialites indicates eukaryotes are more diverse than previously reported. Although this comparison shows that eukaryotic communities in hypersaline habitats with varying physicochemical characteristics are unique, several groups are commonly found, including diverse alveolates, strameonopiles, and fungi, as well as radiolaria. Many eukaryote sequences (SSU) in both regions also have no close homologues in public databases, suggesting that these environments host unique microbial eukaryote assemblages with the potential to enhance our understanding of the capacity of eukaryotes to adapt to hypersaline conditions. PMID:25369746

Bioretention storm water control measures decrease the toxicity of copper roof runoff.

PubMed

LaBarre, William J; Ownby, David R; Rader, Kevin J; Lev, Steven M; Casey, Ryan E

2017-06-01

The present study evaluated the ability of 2 different bioretention storm water control measures (SCMs), planter boxes and swales, to decrease the toxicity of sheet copper (Cu) roofing runoff to Daphnia magna. The present study quantified changes in storm water chemistry as it passed through the bioretention systems and utilized the biotic ligand model (BLM) to assess whether the observed D. magna toxicity could be predicted by variations found in water chemistry. Laboratory toxicity tests were performed using select storm samples with D. magna cultured under low ionic strength conditions that were appropriate for the low ionic strength of the storm water samples being tested. The SCMs decreased toxicity of Cu roof runoff in both the BLM results and the storm water bioassays. Water exiting the SCMs was substantially higher than influent runoff in pH, ions, alkalinity, and dissolved organic carbon and substantially lower in total and dissolved Cu. Daphnids experienced complete mortality in untreated runoff from the Cu roof (the SCM influent); however, for planter and swale effluents, survival averaged 86% and 95%, respectively. The present study demonstrated that conventional bioretention practices, including planter boxes and swales, are capable of decreasing the risk of adverse effects from sheet Cu roof runoff to receiving systems, even before considering dilution of effluents in those receiving systems and associated further reductions in copper bioavailability. Environ Toxicol Chem 2017;36:1680-1688. © 2016 SETAC. © 2016 SETAC.

Hydrothermal sediments are a source of water column Fe and Mn in the Bransfield Strait, Antarctica

NASA Astrophysics Data System (ADS)

Aquilina, Alfred; Homoky, William B.; Hawkes, Jeffrey A.; Lyons, Timothy W.; Mills, Rachel A.

2014-07-01

Short sediment cores were collected from ∼1100 m water depth at the top of Hook Ridge, a submarine volcanic edifice in the Central Basin of the Bransfield Strait, Antarctica, to assess Fe and Mn supply to the water column. Low-temperature hydrothermal fluids advect through these sediments and, in places, subsurface H2S is present at high enough concentrations to support abundant Sclerolinum sp., an infaunal tubeworm that hosts symbiotic thiotrophic bacteria. The water column is fully oxic, and oxygen penetration depths at all sites are 2-5 cmbsf. Pore water Fe and Mn content is high within the subsurface ferruginous zone (max. 565 μmol Fe L-1, >3-7 cmbsf)-14-18 times higher than values measured at a nearby, background site of equivalent water depth. Diffusion and advection of pore waters supply significant Fe and Mn to the surface sediment. Sequential extraction of the sediment demonstrates that there is a significant enrichment in a suite of reactive, authigenic Fe minerals in the upper 0-5 cm of sediment at one site characterised by weathered crusts at the seafloor. At a site with only minor authigenic mineral surface enrichment we infer that leakage of pore water Fe and Mn from the sediment leads to enriched total dissolvable Fe and Mn in bottom waters. An Eh sensor mounted on a towed package mapped a distinct Eh signature above this coring site which is dispersed over several km at the depth of Hook Ridge. We hypothesise that the main mechanism for Fe and Mn efflux from the sediment is breach of the surface oxic layer by the abundant Sclerolinum sp., along with episodic enhancements by physical mixing and resuspension of sediment in this dynamic volcanic environment. We propose that Hook Ridge sediments are an important source of Fe and Mn to the deep waters of the Central Basin in the Bransfield Strait, where concentrations are sustained by the benthic flux, and Fe is stabilised in the water column as either colloidal phases or ligand-bound dissolved

Adsorptive removal of heavy metals from water using sodium titanate nanofibres loaded onto GAC in fixed-bed columns.

PubMed

Sounthararajah, D P; Loganathan, P; Kandasamy, J; Vigneswaran, S

2015-04-28

Heavy metals are serious pollutants in aquatic environments. A study was undertaken to remove Cu, Cd, Ni, Pb and Zn individually (single metal system) and together (mixed metals system) from water by adsorption onto a sodium titanate nanofibrous material. Langmuir adsorption capacities (mg/g) at 10(-3)M NaNO3 ionic strength in the single metal system were 60, 83, 115 and 149 for Ni, Zn, Cu, and Cd, respectively, at pH 6.5 and 250 for Pb at pH 4.0. In the mixed metals system they decreased at high metals concentrations. In column experiments with 4% titanate material and 96% granular activated carbon (w/w) mixture at pH 5.0, the metals breakthrough times and adsorption capacities (for both single and mixed metals systems) decreased in the order Pb>Cd, Cu>Zn>Ni within 266 bed volumes. The amounts adsorbed were up to 82 times higher depending on the metal in the granular activated carbon+titanate column than in the granular activated carbon column. The study showed that the titanate material has high potential for removing heavy metals from polluted water when used with granular activated carbon at a very low proportion in fixed-bed columns. Copyright © 2015 Elsevier B.V. All rights reserved.

BENTHIC AND WATER COLUMN PROCESSES IN A SUBTROPICAL ESTUARY: EFFECTS OF LIGHT ON OXYGEN FLUXES

EPA Science Inventory

Murrell, M.C., J.D. Hagy, J.G. Campbell and J.M. Caffrey. In press. Benthic and Water Column Processes in a Subtropical Estuary: Effects of Light on Oxygen Fluxes (Abstract). To be presented at the ASLO 2004 Summer Meeting: The Changing Landscapes of Oceans and Freshwater, 13-18 ...

Biological nitrogen removal using soil columns for the reuse of reclaimed water: Performance and microbial community analysis.

PubMed

Sun, Jiaji; Chen, Lei; Rene, Eldon R; Hu, Qian; Ma, Weifang; Shen, Zhenyao

2018-07-01

The main aim of this study was to remove nitrogen compounds from reclaimed water and reuse the water in semi-arid riverine lake systems. In order to assess the nitrogen removal efficiencies in different natural environments, laboratory scale column experiments were performed using sterilized soil (SS), silty clay (SC), soil with submerged plant (SSP) and biochar amendment soil (BCS). The initial concentration of NO 3 - -N and the flow rate was maintained constant at 15 mg L -1 and 0.6 ± 0.1 m d -1 , respectively. Among the tested columns, both SSP and BCS were able to achieve NO 3 - -N levels <0.2 mg L -1 in the treated reclaimed water. The results from bacterial community structure analysis, using 454 pyrosequencing of 16s rRNA genes, showed that the dominant denitrifier was Bacillus at the genera level. Copyright © 2018 Elsevier Ltd. All rights reserved.

Estimation of soil organic partition coefficients: from retention factors measured by soil column chromatography with water as eluent.

PubMed

Xu, Feng; Liang, Xinmiao; Lin, Bingcheng; Schramm, Karl-Werner; Kettrup, Antonius

2002-08-30

The retention factors (k) of 104 hydrophobic organic chemicals (HOCs) were measured in soil column chromatography (SCC) over columns filled with three naturally occurring reference soils and eluted with Milli-Q water. A novel method for the estimation of soil organic partition coefficient (Koc) was developed based on correlations with k in soil/water systems. Strong log Koc versus log k correlations (r>0.96) were found. The estimated Koc values were in accordance with the literature values with a maximum deviation of less than 0.4 log units. All estimated Koc values from three soils were consistent with each other. The SCC approach is promising for fast screening of a large number of chemicals in their environmental applications.

Developmental toxicity, acute toxicity and mutagenicity testing in freshwater snails Biomphalaria glabrata (Mollusca: Gastropoda) exposed to chromium and water samples.

PubMed

Tallarico, Lenita de Freitas; Borrely, Sueli Ivone; Hamada, Natália; Grazeffe, Vanessa Siqueira; Ohlweiler, Fernanda Pires; Okazaki, Kayo; Granatelli, Amanda Tosatte; Pereira, Ivana Wuo; Pereira, Carlos Alberto de Bragança; Nakano, Eliana

2014-12-01

A protocol combining acute toxicity, developmental toxicity and mutagenicity analysis in freshwater snail Biomphalaria glabrata for application in ecotoxicological studies is described. For acute toxicity testing, LC50 and EC50 values were determined; dominant lethal mutations induction was the endpoint for mutagenicity analysis. Reference toxicant potassium dichromate (K2Cr2O7) was used to characterize B. glabrata sensitivity for toxicity and cyclophosphamide to mutagenicity testing purposes. Compared to other relevant freshwater species, B. glabrata showed high sensitivity: the lowest EC50 value was obtained with embryos at veliger stage (5.76mg/L). To assess the model applicability for environmental studies, influent and effluent water samples from a wastewater treatment plant were evaluated. Gastropod sensitivity was assessed in comparison to the standardized bioassay with Daphnia similis exposed to the same water samples. Sampling sites identified as toxic to daphnids were also detected by snails, showing a qualitatively similar sensitivity suggesting that B. glabrata is a suitable test species for freshwater monitoring. Holding procedures and protocols implemented for toxicity and developmental bioassays showed to be in compliance with international standards for intra-laboratory precision. Thereby, we are proposing this system for application in ecotoxicological studies. Copyright © 2014 Elsevier Inc. All rights reserved.

BROAD SPECTRUM ANALYSIS FOR TRACE ORGANIC POLLUTANTS IN LARGE VOLUMES OF WATER BY XAD RESINS-COLUMN DESIGN-FACTS AND MYTHS.

USGS Publications Warehouse

Gibs, J.; Wicklund, A.; Suffet, I.H.

1986-01-01

The 'rule of thumb' that large volumes of water can be sampled for trace organic pollutants by XAD resin columns which are designed by small column laboratory studies or pure compounds is examined and shown to be a problem. A theory of multicomponent breakthrough is presented as a frame of reference to help solve the problem and develop useable criteria to aid the design of resin columns. An important part of the theory is the effect of humic substances on the breakthrough character of multicomponent chemical systems.

Model Predictive Control-based Power take-off Control of an Oscillating Water Column Wave Energy Conversion System

NASA Astrophysics Data System (ADS)

Rajapakse, G.; Jayasinghe, S. G.; Fleming, A.; Shahnia, F.

2017-07-01

Australia’s extended coastline asserts abundance of wave and tidal power. The predictability of these energy sources and their proximity to cities and towns make them more desirable. Several tidal current turbine and ocean wave energy conversion projects have already been planned in the coastline of southern Australia. Some of these projects use air turbine technology with air driven turbines to harvest the energy from an oscillating water column. This study focuses on the power take-off control of a single stage unidirectional oscillating water column air turbine generator system, and proposes a model predictive control-based speed controller for the generator-turbine assembly. The proposed method is verified with simulation results that show the efficacy of the controller in extracting power from the turbine while maintaining the speed at the desired level.

Fate of parabens and 4-hydroxybenzoic acid in aquifer materials columns during step experiments with fresh and sea waters

NASA Astrophysics Data System (ADS)

López-Ortiz, C. M.; Boluda-Botella, N.; Prats-Rico, D.; Sentana-Gadea, I.

2018-02-01

Coastal areas submitted to seawater intrusion and with discharges from urban and industrial wastewaters, municipal landfill leachates, rivers, recreational waters and other sources are sensitive to be polluted with parabens. Understanding the fate of these compounds in environmental studies, it requires previously the knowledge of the reactive processes in controlled conditions. In this research, laboratory columns experiments were carried out with a group of parabens (methyl-, ethyl-, propyl- and butylparaben) and their main degradation compound (4-hydroxybenzoic acid) to study mainly the dynamic sorption processes in different aquifer materials (100% sand and heterogeneous: 81% sand, 9% silt and 10% clay) and with fresh and sea waters, the end members of seawater intrusions. To the column hydrodynamic characterization, tracer assays with increase and decrease of salinity were performed, to obtain the mean residence time of each column and other transport parameters which allow us to compare parabens' sorption in different conditions. The results of the adsorption and desorption of parabens in the sand column demonstrated be fast and simultaneous, with a short delay and without influence of the water salinity. Very different results were found in the column experiments with heterogeneous material, where the presence of clay and organic matter increase the time of adsorption/desorption as the length of the alkyl chain paraben increased, according with their hydrophobicity. It should be noted that despite the quick desorption of the major quantities of parabens, the elution of their trace concentrations was very slow (for the seawater, the buthylparaben required a dimensionless time of 800). Planning the restoration of a coastal aquifer with freshwater, and in the conditions of the studied sand column experiment, it will need a dimensionless time of 160. However, it is necessary to take into account that the studied parabens and 4-hydroxybenzoic acid are

Toxic impact of bromide and iodide on drinking water disinfected with chlorine or chloramines.

PubMed

Yang, Yang; Komaki, Yukako; Kimura, Susana Y; Hu, Hong-Ying; Wagner, Elizabeth D; Mariñas, Benito J; Plewa, Michael J

2014-10-21

Disinfectants inactivate pathogens in source water; however, they also react with organic matter and bromide/iodide to form disinfection byproducts (DBPs). Although only a few DBP classes have been systematically analyzed for toxicity, iodinated and brominated DBPs tend to be the most toxic. The objectives of this research were (1) to determine if monochloramine (NH2Cl) disinfection generated drinking water with less toxicity than water disinfected with free chlorine (HOCl) and (2) to determine the impact of added bromide and iodide in conjunction with HOCl or NH2Cl disinfection on mammalian cell cytotoxicity and genomic DNA damage induction. Water disinfected with chlorine was less cytotoxic but more genotoxic than water disinfected with chloramine. For both disinfectants, the addition of Br(-) and I(-) increased cytotoxicity and genotoxicity with a greater response observed with NH2Cl disinfection. Both cytotoxicity and genotoxicity were highly correlated with TOBr and TOI. However, toxicity was weakly and inversely correlated with TOCl. Thus, the forcing agents for cytotoxicity and genotoxicity were the generation of brominated and iodinated DBPs rather than the formation of chlorinated DBPs. Disinfection practices need careful consideration especially when using source waters containing elevated bromide and iodide.

Measuring and modeling three-dimensional water uptake of a growing faba bean (Vicia faba) within a soil column

NASA Astrophysics Data System (ADS)

Huber, Katrin; Koebernick, Nicolai; Kerkhofs, Elien; Vanderborght, Jan; Javaux, Mathieu; Vetterlein, Doris; Vereecken, Harry

2014-05-01

A faba bean was grown in a column filled with a sandy soil, which was initially close to saturation and then subjected to a single drying cycle of 30 days. The column was divided in four hydraulically separated compartments using horizontal paraffin layers. Paraffin is impermeable to water but penetrable by roots. Thus by growing deeper, the roots can reach compartments that still contain water. The root architecture was measured every second day by X-ray CT. Transpiration rate, soil matric potential in four different depths, and leaf area were measured continously during the experiment. To investigate the influence of the partitioning of available soil water in the soil column on water uptake, we used R-SWMS, a fully coupled root and soil water model [1]. We compared a scenario with and without the split layers and investigated the influence on root xylem pressure. The detailed three-dimensional root architecture was obtained by reconstructing binarized root images manually with a virtual reality system, located at the Juelich Supercomputing Centre [2]. To verify the properties of the root system, we compared total root lengths, root length density distributions and root surface with estimations derived from Minkowski functionals [3]. In a next step, knowing the change of root architecture in time, we could allocate an age to each root segment and use this information to define age dependent root hydraulic properties that are required to simulate water uptake for the growing root system. The scenario with the split layers showed locally much lower pressures than the scenario without splits. Redistribution of water within the unrestricted soil column led to a more uniform distribution of water uptake and lowers the water stress in the plant. However, comparison of simulated and measured pressure heads with tensiometers suggested that the paraffin layers were not perfectly hydraulically isolating the different soil layers. We could show compensation efficiency of

Virus movement in soil columns flooded with secondary sewage effluent.

PubMed Central

Lance, J C; Gerba, C P; Melnick, J L

1976-01-01

Secondary sewage effluent containing about 3 X 10(4) plaque-forming units of polio virus type 1 (LSc) per ml was passed through columns 250 cm in length packed with calcareous sand from an area in the Salt River bed used for ground-water recharge of secondary sewage effluent. Viruses were not detected in 1-ml samples extracted from the columns below the 160-cm level. However, viruses were detected in 5 of 43 100-ml samples of the column drainage water. Most of the viruses were adsorbed in the top 5 cm of soil. Virus removal was not affected by the infiltration rate, which varied between 15 and 55 cm/day. Flooding a column continuosly for 27 days with the sewage water virus mixture did not saturate the top few centimeters of soil with viruses and did not seem to affect virus movement. Flooding with deionized water caused virus desorption from the soil and increased their movement through the columns. Adding CaCl2 to the deionized water prevented most of the virus desorption. Adding a pulse of deionized water followed by sewage water started a virus front moving through the columns, but the viruses were readsorbed and none was detected in outflow samples. Drying the soil for 1 day between applying the virus and flooding with deionized water greatly reduced desorption, and drying for 5 days prevented desorption. Large reductions (99.99% or more) of virus would be expected after passage of secondary sewage effluent through 250 cm of the calcareous sand similar to that used in our laboratory columns unless heavy rains fell within 1 day after the application of sewage stopped. Such virus movement could be minimized by the proper management of flooding and drying cycles. PMID:185960

Observation of Mountain Lee Waves with MODIS NIR Column Water Vapor

NASA Technical Reports Server (NTRS)

Lyapustin, A.; Alexander, M. J.; Ott, L.; Molod, A.; Holben, B.; Susskind, J.; Wang, Y.

2014-01-01

Mountain lee waves have been previously observed in data from the Moderate Resolution Imaging Spectroradiometer (MODIS) "water vapor" 6.7 micrometers channel which has a typical peak sensitivity at 550 hPa in the free troposphere. This paper reports the first observation of mountain waves generated by the Appalachian Mountains in the MODIS total column water vapor (CWV) product derived from near-infrared (NIR) (0.94 micrometers) measurements, which indicate perturbations very close to the surface. The CWV waves are usually observed during spring and late fall or some summer days with low to moderate CWV (below is approx. 2 cm). The observed lee waves display wavelengths from3-4 to 15kmwith an amplitude of variation often comparable to is approx. 50-70% of the total CWV. Since the bulk of atmospheric water vapor is confined to the boundary layer, this indicates that the impact of thesewaves extends deep into the boundary layer, and these may be the lowest level signatures of mountain lee waves presently detected by remote sensing over the land.

Development and application of a marine sediment pore-water toxicity test using Ulva fasciata zoospores

USGS Publications Warehouse

Hooten, Russell L.; Carr, R. Scott

1998-01-01

An acute (96 h) pore-water toxicity test protocol using germination and growth of Ulva fasciatazoospores as endpoints was developed to test the toxicity of marine and estuarine sediment pore-water samples. Tests with an organic toxicant (sodium dodecyl sulfate; SDS), three metals (Cd, Cu, and Zn), and ammonia (NH3) were conducted to determine zoospore sensitivity. Zoospore germination and gametophyte growth were as sensitive to SDS as sea urchin (Arbacia punctulata) fertilization and embryological development. Zoospore sensitivity to metals was greater than or comparable to that of adult macroalgae. Zoospores were less sensitive to NH3than were other commonly used toxicity test organisms. Test results using this algal assay with sediment pore-water samples with high NH3 concentrations were compared with results from sea urchin fertilization and embryological development tests for the same samples. Ulva fasciatazoospore germination was not affected by samples with high NH3 concentrations that were toxic in both sea urchin tests. Zoospore tolerance of NH3 and sensitivity to other contaminants indicate that their response may be useful in toxicity identification evaluation studies with pore-water samples that contain high concentrations of unionized NH3.

An inexpensive and stable LED Sun photometer for measuring the water vapor column over South Texas from 1990 to 2001

NASA Astrophysics Data System (ADS)

Mims, Forrest M.

2002-07-01

A Sun photometer that uses near-infrared light-emitting diodes (LEDs) as spectrally-selective photodetectors has measured total column water vapor in South Texas since February 1990. The 12 years of solar noon observations to date are correlated with upper air soundings at Del Rio, Texas (r2 = 0.75), and highly correlated with measurements by a Microtops II filter Sun photometer (r2 = 0.94). LEDs are inexpensive and have far better long term stability than the interference filters in conventional Sun photometers. The LED Sun photometer therefore provides an inexpensive, stable and portable means for measuring column water vapor.

A new biological test of water toxicity-yeast Saccharomyces cerevisiae conductometric test.

PubMed

Dolezalova, Jaroslava; Rumlova, Lubomira

2014-11-01

This new biological test of water toxicity is based on monitoring of specific conductivity changes of yeast Saccharomyces cerevisiae suspension as a result of yeast fermentation activity inhibition in toxic conditions. The test was verified on ten substances with various mechanisms of toxic effect and the results were compared with two standard toxicity tests based on Daphnia magna mobility inhibition (EN ISO 6341) and Vibrio fischeri bioluminescence inhibition (EN ISO 11348-2) and with the results of the S. cerevisiae lethal test (Rumlova and Dolezalova, 2012). The new biological test - S. cerevisiae conductometric test - is an express method developed primarily for field conditions. It is applicable in case of need of immediate information about water toxicity. Fast completion is an advantage of this test (time necessary for test completion is about 60min), the test is simple and the test organism - dried instant yeast - belongs among its biggest advantages because of its long-term storage life and broad availability. Copyright © 2014 Elsevier B.V. All rights reserved.

Development of a Low Toxicity Urine Pretreatment for Water Recovery in Space

NASA Technical Reports Server (NTRS)

Adam, Niklas; Alvarez, Giraldo; Mitchell, Julie; Pickering, Karen; Shull, Sarah; Carrier, Chris; Vega, Letty

2015-01-01

Wastewater stabilization was an essential component of the spacecraft water cycle. The purpose of stabilizing wastewater was two-fold. First, stabilization prevents the breakdown of urea into ammonia, a toxic gas at high concentrations. Second, it prevents the growth of microorganisms, thereby mitigating hardware and water quality issues due to due biofilm and planktonic growth. Current stabilization techniques involve oxidizers and strong acids (pH=2) such as chromic and sulfuric acid, which are highly toxic and pose a risk to crew health. The purpose of this effort was to explore less toxic stabilization techniques, such as food-grade and commercial care preservatives. Additionally, certain preservatives were tested in the presence of a low-toxicity organic acid. Triplicate 300-mL volumes of urine were dosed with a predetermined quantity of stabilizer and stored for two weeks. During that time, pH, total organic carbon (TOC), ammonia, and turbidity were monitored. Those preservatives that showed the lowest visible microbial growth and stable pH were further tested in a six-month stability study. The results of the six-month study are also included in this paper. Additionally, the pretreatment formulations were tested to determine if the pretreated urine could be distilled to remove 85% of the water, as would occur on the ISS. The goal of the pretreatment was to produce no solids in the resulting brine at 85% water recovery.

Lake Mixing Regime Influences Arsenic Transfer from Sediments into the Water Column and Uptake in Plankton

NASA Astrophysics Data System (ADS)

Gawel, J.; Barrett, P. M.; Hull, E.; Burkart, K.; McLean, J.; Hargrave, O.; Neumann, R.

2017-12-01

The former ASARCO copper smelter in Ruston, WA, now a Superfund site, contaminated a large area of the south-central Puget Sound region with arsenic over its almost 100-year history. Arsenic, a priority Superfund contaminant and carcinogen, is a legacy pollutant impacting aquatic ecosystems in urban lakes downwind of the ASARCO emissions stack. We investigated the impact of lake mixing regime on arsenic transfer from sediments into lake water and aquatic biota. We regularly collected water column and plankton samples from four study lakes for two years, and deployed sediment porewater peepers and sediment traps to estimate arsenic flux rates to and from the sediments. In lakes with strong seasonal stratification, high aqueous arsenic concentrations were limited to anoxic hypolimnetic waters while low arsenic concentrations were observed in oxic surface waters. However, in polymictic, shallow lakes, we observed elevated arsenic concentrations throughout the entire oxic water column. Sediment flux estimates support higher rates of arsenic release from sediments and vertical transport. Because high arsenic in oxic waters results in spatial overlap between arsenate, a phosphate analog, and lake biota, we observed enhanced trophic transfer of arsenic in polymictic, shallow study lakes, with higher arsenic accumulation (up to an order of magnitude) in both phytoplankton and zooplankton compared to stratified lakes. Chemical and physical mechanisms for higher steady-state arsenic concentrations will be explored. Our work demonstrates that physical mixing processes coupled with sediment/water redox status exert significant control over bioaccumulation, making shallow, periodically-mixed urban lakes uniquely vulnerable to environmental and human health risks from legacy arsenic contamination.

Βiocolloid and colloid transport through water-saturated columns packed with glass beads: Effect of gravity

NASA Astrophysics Data System (ADS)

Chrysikopoulos, C. V.; Syngouna, V. I.

2013-12-01

The role of gravitational force on biocolloid and colloid transport in water-saturated columns packed with glass beads was investigated. Transport experiments were performed with biocolloids (bacteriophages: ΦΧ174, MS2) and colloids (clays: kaolinite KGa-1b, montmorillonite STx-1b). The packed columns were placed in various orientations (horizontal, vertical, and diagonal) and a steady flow rate of Q=1.5 mL/min was applied in both up-flow and down-flow modes. All experiments were conducted under electrostatically unfavorable conditions. The experimental data were fitted with a newly developed, analytical, one dimensional, colloid transport model, accounting for gravity effects. The results revealed that flow direction has a significant influence on particle deposition. The rate of particle deposition was shown to be greater for up-flow than for down-flow direction, suggesting that gravity was a significant driving force for biocolloid and colloid deposition. Schematic illustration of a packed column with up-flow velocity having orientation (-i) with respect to gravity. The gravity vector components are: g(i)= g(-z) sinβ i, and g(-j)= -g(-z) cosβ j. Experimental setup showing the various column arrangements: (a) horizontal, (b) diagonal, and (c) vertical.

Water-column cooling and sea surface salinity increase in the upwelling region off central-south Chile driven by a poleward displacement of the South Pacific High

NASA Astrophysics Data System (ADS)

Schneider, Wolfgang; Donoso, David; Garcés-Vargas, José; Escribano, Rubén

2017-02-01

Here we present results of direct observations of seawater temperature and salinity over the continental shelf off central-south Chile that shows an unprecedented cooling of the entire water column and an increase in upper layer salinity during 2002 to 2013. We provide evidence that this phenomenon is related to the intensification but mostly to a recent southward displacement of the South Pacific High over the same period, from 2007 on. This in turn has accelerated alongshore, equatorward, subtropical coastal upwelling favorable winds, particularly during winter, injecting colder water from below into the upper water column. Consequently, the environmental conditions on the shelf off central-south Chile shifted from a warmer (fresher) to a cooler (saltier) phase; water column temperature dropped from 11.7 °C (2003-2006) to 11.3 °C (2007-2012) and upper layer salinity rose by 0.25; water column stratification gradually decreased. The biological impacts of such abrupt cooling are apparently already happening in this coastal ecosystem, as recent evidence shows substantial changes in the plankton community and negative trends in zooplankton biomass over the same period.

Radio-toxicity of spent fuel of the advanced heavy water reactor.

PubMed

Anand, S; Singh, K D S; Sharma, V K

2010-01-01

The Advanced Heavy Water Reactor (AHWR) is a new power reactor concept being developed at Bhabha Atomic Research Centre, Mumbai. The reactor retains many desirable features of the existing Pressurised Heavy Water Reactor (PHWR), while incorporating new, advanced safety features. The reactor aims to utilise the vast thorium resources available in India. The reactor core will use plutonium as the make-up fuel, while breeding (233)U in situ. On account of this unique combination of fuel materials, the operational characteristics of the fuel as determined by its radioactivity, decay heat and radio-toxicity are being viewed with great interest. Radio-toxicity of the spent fuel is a measure of potential radiological hazard to the members of the public and also important from the ecological point of view. The radio-toxicity of the AHWR fuel is extremely high to start with, being approximately 10(4) times that of the fresh natural U fuel used in a PHWR, and continues to remain relatively high during operation and subsequent cooling. A unique feature of this fuel is the peak observed in its radio-toxicity at approximately 10(5) y of decay cooling. The delayed increase in fuel toxicity has been traced primarily to a build-up of (229)Th, (230)Th and (226)Ra. This phenomenon has been observed earlier for thorium-based fuels and is confirmed for the AHWR fuel. This paper presents radio-toxicity data for AHWR spent fuel up to a period of 10(6) y and the results are compared with the radio-toxicity of PHWR.

Ground and surface water developmental toxicity at a municipal landfill--Description and weather-related variation

USGS Publications Warehouse

Bruner, M.A.; Rao, M.; Dumont, J.N.; Hull, M.; Jones, T.; Bantle, J.A.

1998-01-01

Contaminated groundwater poses a significant health hazard and may also impact wildlife such as amphibians when it surfaces. Using FETAX (Frog Embryo Teratogenesis Assay-Xenopus), the developmental toxicity of ground and surface water samples near a closed municipal landfill at Norman, OK, were evaluated. The groundwater samples were taken from a network of wells in a shallow, unconfined aquifer downgradient from the landfill. Surface water samples were obtained from a pond and small stream adjacent to the landfill. Surface water samples from a reference site in similar habitat were also analyzed. Groundwater samples were highly toxic in the area near the landfill, indicating a plume of toxicants. Surface water samples from the landfill site demonstrated elevated developmental toxicity. This toxicity was temporally variable and was significantly correlated with weather conditions during the 3 days prior to sampling. Mortality was negatively correlated with cumulative rain and relative humidity. Mortality was positively correlated with solar radiation and net radiation. No significant correlations were observed between mortality and weather parameters for days 4–7 preceding sampling.

Penetration of different human pathogenic viruses into sand columns percolated with distilled water, groundwater, or wastewater.

PubMed Central

Dizer, H; Nasser, A; Lopez, J M

1984-01-01

The adsorption of several enteroviruses and rotavirus SA11 to sand from an aquifer in the Federal Republic of Germany was estimated in sand-filled columns loaded with ca. 10(7) PFU and run at a velocity of 2.5 m/day for 12 h. After either distilled water, groundwater, secondary effluent, or tertiary effluent was percolated, the sand core was slowly extruded out of the column and cut in 1-cm slices. The slices were eluted with nutrient broth, and the amount of viruses in the broth was estimated. The best adsorption was promoted by groundwater and tertiary effluent, followed by distilled water and secondary effluent. Similar experiments, carried out at different percolation rates, indicated that a 50-day underground stay of recharged water probably suffices to eliminate viruses in the groundwater-recharged tertiary effluent. However, when viruses and sand were incubated in the presence of the surfactants sodium dodecyl sulfate, nonyl phenol, dodigen 226, or alkylbenzylsulfonate, the adsorption of the viruses was substantially diminished. Experiments in the presence of nonyl phenol seem to indicate that hydrophobic interactions are involved in the adsorption of viruses to sand. PMID:6324676

Leaching of heavy metals from E-waste in simulated landfill columns

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li Yadong; Richardson, Jay B.; Mark Bricka, R.

2009-07-15

In recent history the volume of electronic products purchased by consumers has dramatically escalated. As a result this has produced an ever-increasing electronic waste (E-waste) stream, which has generated concerns regarding the E-waste's potential for adversely impacting the environment. The leaching of toxic substances from obsolete personal computers (PCs) and cathode ray tubes (CRTs) of televisions and monitors, which are the most significant components in E-waste stream, was studied using landfill simulation in columns. Five columns were employed. One column served as a control which was filled with municipal solid waste (MSW), two columns were filled with a mixture ofmore » MSW and CRTs, and the other two were filled with MSW and computer components including printed wire boards, hard disc drives, floppy disc drives, CD/DVD drives, and power supply units. The leachate generated from the columns was monitored for toxic materials throughout the two-year duration of the study. Results indicate that lead (Pb) and various other heavy metals that were of environmental and health concern were not detected in the leachate from the simulators. When the samples of the solids were collected from underneath the E-waste in the columns and were analyzed, significant amount of Pb was detected. This indicates that Pb could readily leach from the E-waste, but was absorbed by the solids around the E-waste materials. While Pb was not observed in the leachate in this study, it is likely that the Pb would eventually enter the leachate after a long term transport.« less

Novel Robotic Platforms for the Accurate Sampling and Monitoring of Water Columns

PubMed Central

Fernández, Roemi; Apalkov, Andrey; Armada, Manuel

2016-01-01

The hydrosphere contains large amounts of suspended particulate material, including living and non-living material that can be found in different compositions and concentrations, and that can be composed of particles of different sizes. The study of this particulate material along water columns plays a key role in understanding a great variety of biological, chemical, and physical processes. This paper presents the conceptual design of two patented robotic platforms that have been conceived for carrying out studies of water properties at desired depths with very high accuracy in the vertical positioning. One platform has been specially designed for operating near to a reservoir bottom, while the other is intended to be used near the surface. Several experimental tests have been conducted in order to validate the proposed approaches. PMID:27589745

Biotic and abiotic interactions in aquatic microcosms determine fate and toxicity of Ag nanoparticles. Part 1. Aggregation and dissolution.

PubMed

Unrine, Jason M; Colman, Benjamin P; Bone, Audrey J; Gondikas, Andreas P; Matson, Cole W

2012-07-03

To better understand their fate and toxicity in aquatic environments, we compared the aggregation and dissolution behavior of gum arabic (GA) and polyvinylpyrrolidone (PVP) coated Ag nanoparticles (NPs) in aquatic microcosms. There were four microcosm types: surface water; water and sediment; water and aquatic plants; or water, sediment, and aquatic plants. Dissolution and aggregation behavior of AgNPs were examined using ultracentrifugation, ultrafiltration, and asymmetrical flow field flow fractionation coupled to ultraviolet-visible spectroscopy, dynamic and static laser light scattering, and inductively coupled plasma mass spectrometry. Plants released dissolved organic matter (DOM) into the water column either through active or passive processes in response to Ag exposure. This organic matter fraction readily bound Ag ions. The plant-derived DOM had the effect of stabilizing PVP-AgNPs as primary particles, but caused GA-AgNPs to be removed from the water column, likely by dissolution and binding of released Ag ions on sediment and plant surfaces. The destabilization of the GA-AgNPs also corresponded with X-ray absorption near edge spectroscopy results which suggest that 22-28% of the particulate Ag was associated with thiols and 5-14% was present as oxides. The results highlight the potential complexities of nanomaterial behavior in response to biotic and abiotic modifications in ecosystems, and may help to explain differences in toxicity of Ag observed in realistic exposure media compared to simplified laboratory exposures.

Effects of salt pond restoration on benthic flux: Sediment as a source of nutrients to the water column

USGS Publications Warehouse

Topping, Brent R.; Kuwabara, James S.; Carter, James L.; Garrettt, Krista K.; Mruz, Eric; Piotter, Sarah; Takekawa, John Y.

2016-01-01

Understanding nutrient flux between the benthos and the overlying water (benthic flux) is critical to restoration of water quality and biological resources because it can represent a major source of nutrients to the water column. Extensive water management commenced in the San Francisco Bay, Beginning around 1850, San Francisco Bay wetlands were converted to salt ponds and mined extensively for more than a century. Long-term (decadal) salt pond restoration efforts began in 2003. A patented device for sampling porewater at varying depths, to calculate the gradient, was employed between 2010 and 2012. Within the former ponds, the benthic flux of soluble reactive phosphorus and that of dissolved ammonia were consistently positive (i.e., moving out of the sediment into the water column). The lack of measurable nitrate or nitrite concentration gradients across the sediment-water interface suggested negligible fluxes for dissolved nitrate and nitrite. The dominance of ammonia in the porewater indicated anoxic sediment conditions, even at only 1 cm depth, which is consistent with the observed, elevated sediment oxygen demand. Nearby openestuary sediments showed much lower benthic flux values for nutrients than the salt ponds under resortation. Allochthonous solute transport provides a nutrient advective flux for comparison to benthic flux. For ammonia, averaged for all sites and dates, benthic flux was about 80,000 kg/year, well above the advective flux range of −50 to 1500 kg/year, with much of the variability depending on the tidal cycle. By contrast, the average benthic flux of soluble reactive phosphorus was about 12,000 kg/year, of significant magnitude, but less than the advective flux range of 21,500 to 30,000 kg/year. These benthic flux estimates, based on solute diffusion across the sediment-water interface, reveal a significant nutrient source to the water column of the pond which stimulates algal blooms (often autotrophic). This benthic source may be

Variations in toxicity of semi-coking wastewater treatment processes and their toxicity prediction.

PubMed

Ma, Xiaoyan; Wang, Xiaochang; Liu, Yongjun; Gao, Jian; Wang, Yongkun

2017-04-01

Chemical analyses and bioassays using Vibrio fischeri and Daphnia magna were conducted to evaluate comprehensively the variation of biotoxicity caused by contaminants in wastewater from a semi-coking wastewater treatment plant (WWTP). Pretreatment units (including an oil-water separator, a phenols extraction tower, an ammonia stripping tower, and a regulation tank) followed by treatment units (including anaerobic-oxic treatment units, coagulation-sedimentation treatment units, and an active carbon adsorption column) were employed in the semi-coking WWTP. Five benzenes, 11 phenols, and five polycyclic aromatic hydrocarbons (PAHs) were investigated as the dominant contaminants in semi-coking wastewater. Because of residual extractant, the phenols extraction process increased acute toxicity to V. fischeri and immobilization and lethal toxicity to D. magna. The acute toxicity of pretreated wastewater to V. fischeri was still higher than that of raw semi-coking wastewater, even though 90.0% of benzenes, 94.8% of phenols, and 81.0% of PAHs were removed. After wastewater pretreatment, phenols and PAHs were mainly removed by anaerobic-oxic and coagulation-sedimentation treatment processes respectively, and a subsequent active carbon adsorption process further reduced the concentrations of all target chemicals to below detection limits. An effective biotoxicity reduction was found during the coagulation-sedimentation and active carbon adsorption treatment processes. The concentration addition model can be applied for toxicity prediction of wastewater from the semi-coking WWTP. The deviation between the measured and predicted toxicity results may result from the effects of compounds not detectable by instrumental analyses, the synergistic effect of detected contaminants, or possible transformation products. Copyright © 2016. Published by Elsevier Inc.

Mitigation of Liquefaction in Sandy Soils Using Stone Columns

NASA Astrophysics Data System (ADS)

Selcuk, Levent; Kayabalı, Kamil

2010-05-01

Soil liquefaction is one of the leading causes of earthquake-induced damage to structures. Soil improvement methods provide effective solutions to reduce the risk of soil liquefaction. Thus, soil ground treatments are applied using various techniques. However, except for a few ground treatment methods, they generally require a high cost and a lot of time. Especially in order to prevent the risk of soil liquefaction, stone columns conctructed by vibro-systems (vibro-compaction, vibro-replacement) are one of the traditional geotechnical methods. The construction of stone columns not only enhances the ability of clean sand to drain excess pore water during an earthquake, but also increases the relative density of the soil. Thus, this application prevents the development of the excess pore water pressure in sand during earthquakes and keeps the pore pressure ratio below a certain value. This paper presents the stone column methods used against soil liquefaction in detail. At this stage, (a) the performances of the stone columns were investigated in different spacing and diameters of columns during past earthquakes, (b) recent studies about design and field applications of stone columns were presented, and (c) a new design method considering the relative density of soil and the capacity of drenage of columns were explained in sandy soil. Furthermore, with this new method, earthquake performances of the stone columns constructed at different areas were investigated before the 1989 Loma Prieta and the 1994 Northbridge earthquakes, as case histories of field applications, and design charts were compiled for suitable spacing and diameters of stone columns with consideration to the different sandy soil parameters and earhquake conditions. Key Words: Soil improvement, stone column, excess pore water pressure

Evaluating the role of ion composition on the toxicity of copper to Ceriodaphnia dubia in very hard waters.

PubMed

Gensemer, Robert W; Naddy, Rami B; Stubblefield, William A; Hockett, J Russell; Santore, Robert; Paquin, Paul

2002-09-01

The mitigating effect of increasing hardness on metal toxicity is reflected in water quality criteria in the United States over the range of 25-400 mgl(-1) (as CaCO(3)). However, waters in the arid west of the US frequently exceed 400 mgl(-1) hardness, and the applicability of hardness-toxicity relationships in these waters is unknown. Acute toxicity tests with Ceriodaphnia dubia were conducted at hardness levels ranging from approximately 300 to 1,200 mgl(-1) using reconstituted waters that mimic two natural waters with elevated hardness: (1) alkaline desert southwest streams (Las Vegas Wash, NV), and (2) low alkalinity waters from a CaSO(4)-treated mining effluent in Colorado. The moderately-alkaline EPA synthetic hard water was also included for comparison. Copper toxicity did not consistently vary as a function of hardness, but likely as a function of other water quality characteristics (e.g., alkalinity or other correlated factors). The hardness equations used in regulatory criteria, therefore, may not provide an accurate level of protection against copper toxicity in all types of very hard waters. However, the mechanistic Biotic ligand model generally predicted copper toxicity within +/-2X of observed EC(50) values, and thus may be more useful than hardness for modifying water quality criteria.

Toxicity of acid mine pit lake water remediated with limestone and phosphorus.

PubMed

Neil, Luke L; McCullough, Clint D; Lund, Mark A; Evans, Louis H; Tsvetnenko, Yuri

2009-11-01

Pit lakes are increasingly common worldwide and have potential to provide many benefits. However, lake water toxicity may require remediation before beneficial end uses can be realised. Three treatments to remediate AMD (pH approximately 4.8) pit lake water containing elevated concentrations of Al and Zn from Collie, Western Australia were tested in mesocosms. Treatments were: (a) limestone neutralisation (L), (b) phosphorus amendment (P), and (c) combined limestone neutralisation and phosphorus amendment (L+P). Laboratory bioassays with Ceriodaphnia cf. dubia, Chlorella protothecoides and Tetrahymena thermophila assessed remediation. Limestone neutralisation increased pH and reduced heavy metal concentrations by 98% (Al) to 14% (Mg), removing toxicity to the three test species within 2 months. Phosphorus amendment removed toxicity after 6 months of treatment. However, phosphorus amendment to prior limestone neutralisation failed to reduce toxicity more than limestone neutralisation alone. Low concentrations of both phosphorus and nitrogen appear to limit phytoplankton population growth in all treatments.

Toxicity of acid mine pit lake water remediated with limestone and phosphorus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neil, L.L.; McCullough, C.D.; Lund, M.A.

2009-11-15

Pit lakes are increasingly common worldwide and have potential to provide many benefits. However, lake water toxicity may require remediation before beneficial end uses can be realised. Three treatments to remediate AMD (pH similar to 4.8) pit lake water containing elevated concentrations of Al and Zn from Collie, Western Australia were tested in mesocosms. Treatments were: (a) limestone neutralisation (L), (b) phosphorus amendment (P), and c) combined limestone neutralisation and phosphorus amendment (L+P). Laboratory bioassays with Ceriodaphnia cf. dubia, Chlorella protothecoides and Tetrahymena thermophila assessed remediation. Limestone neutralisation increased pH and reduced heavy metal concentrations by 98% (Al) to 14%more » (Mg), removing toxicity to the three test species within 2 months. Phosphorus amendment removed toxicity after 6 months of treatment. However, phosphorus amendment to prior limestone neutralisation failed to reduce toxicity more than limestone neutralisation alone. Low concentrations of both phosphorus and nitrogen appear to limit phytoplankton population growth in all treatments.« less

Detection of toxic industrial chemicals in water supplies using surface-enhanced Raman spectroscopy

NASA Astrophysics Data System (ADS)

Spencer, Kevin M.; Sylvia, James M.; Spencer, Sarah A.; Clauson, Susan L.

2010-04-01

An effective method to create fear in the populace is to endanger the water supply. Homeland Security places significant importance on ensuring drinking water integrity. Beyond terrorism, accidental supply contamination from a spill or chemical residual increases is a concern. A prominent class of toxic industrial chemicals (TICs) is pesticides, which are prevalent in agricultural use and can be very toxic in minute concentrations. Detection of TICs or warfare agents must be aggressive; the contaminant needs to be rapidly detected and identified to enable isolation and remediation of the contaminated water while continuing a clean water supply for the population. Awaiting laboratory analysis is unacceptable as delay in identification and remediation increases the likelihood of infection. Therefore, a portable or online water quality sensor is required that can produce rapid results. In this presentation, Surface-Enhanced Raman Spectroscopy (SERS) is discussed as a viable fieldable sensor that can be immersed directly into the water supply and can provide results in <5 minutes from the time the instrument is turned on until analysis is complete. The ability of SERS to detect several chemical warfare agent degradation products, simulants and toxic industrial chemicals in distilled water, tap water and untreated water will be shown. In addition, results for chemical warfare agent degradation products and simulants will be presented. Receiver operator characteristic (ROC) curves will also be presented.

Acute Toxicity of Ammonia, Nitrite and Nitrate to Shrimp Litopenaeus vannamei Postlarvae in Low-Salinity Water.

PubMed

Valencia-Castañeda, Gladys; Frías-Espericueta, Martin G; Vanegas-Pérez, Ruth C; Pérez-Ramírez, Jesús A; Chávez-Sánchez, María C; Páez-Osuna, Federico

2018-05-12

Shrimp farming in low salinities waters is an alternative to increasing production, and counteracting disease problems in brackish and marine waters. However, in low-salinity waters, toxicity of nitrogen compounds increases, and there is no available data of its acute toxicity in shrimp postlarvae. This study determined the acute toxicity of ammonia, nitrite and nitrate in Litopenaeus vannamei postlarvae in 1 and 3 g/L salinity, as well as the safety levels. The LC 50 confirms that nitrite is more toxic than ammonia and nitrate in low salinity waters, and that its toxicity increases with a decrease in salinity. The safe levels estimated for salinities of 1 and 3 g/L were 0.54 and 0.81 mg/L for total ammonia-N, 0.17 and 0.25 mg/L for NO 2 -N, and 5.6 and 21.5 mg/L for NO 3 -N, respectively.

Influence of water chemistry on the acute toxicity of copper and zinc to the cladoceran Ceriodaphnia cf dubia.

PubMed

Hyne, Ross V; Pablo, Fleur; Julli, Moreno; Markich, Scott J

2005-07-01

This study determined the influence of key water chemistry parameters (pH, alkalinity, dissolved organic carbon [DOC], and hardness) on the aqueous speciation of copper and zinc and its relationship to the acute toxicity of these metals to the cladoceran Ceriodaphnia cf dubia. Immobilization tests were performed for 48-h in synthetic or natural waters buffered at various pH values from 5.5 to 8.4 (other chemical parameters held constant). The toxicity of copper to C. cf dubia decreased fivefold with increasing pH, whereas the toxicity of zinc increased fivefold with increasing pH. The effect of DOC on copper and zinc toxicity to C. cf dubia was determined using natural fulvic acid in the synthetic water. Increasing DOC was found to decrease linearly the toxicity of copper, with the mean effect concentration of copper that immobilized 50% of the cladocerans (EC50) value 45 times higher at 10 mg/L, relative to 0.1 mg/L DOC at pH 6.5. In contrast, the addition of 10 mg/L DOC only resulted in a very small (1.3-fold) reduction in the toxicity of zinc to C. cf dubia. Copper toxicity to C. cf dubia generally did not vary as a function of hardness, whereas zinc toxicity was reduced by a factor of only two, with an increase in water hardness from 44 to 374 mg CaCO3/L. Increasing bicarbonate alkalinity of synthetic waters (30-125 mg/L as CaCO3) decreased the toxicity of copper up to fivefold, which mainly could be attributed to the formation of copper-carbonate complexes, in addition to a pH effect. The toxicity of copper added to a range of natural waters with varying DOC content, pH, and hardness was consistent with the toxicity predicted using the data obtained from the synthetic waters.

Acute and chronic toxicity of effluent water from an abandoned uranium mine.

PubMed

Antunes, S C; Pereira, R; Gonçalves, F

2007-08-01

Inactive or abandoned mines represent a significant source of environmental, chemical, physical, and aesthetic impact. Among concerning situations, the occurrence of abandoned or semi-abandoned mine-associated ponds (for sedimentation of solids, for effluent neutralization, or for washing the ore) is a common feature in this type of system. These ponds are a source of contamination for the groundwater resources and adjacent soils, because they lack appropriate impermeabilization. The use of this water for agriculture may also pose chronic risks to humans. In Portugal, these problems have been diagnosed and some remediation projects have been developed. The purpose of our study was to evaluate the acute and chronic toxicity of water samples collected from the aquatic system surrounding an abandoned uranium mine (Cunha Baixa, Mangualde, Central Portugal). The present study focuses on the water compartment, whose toxicity was evaluated by means of standard toxicity assays using two Daphnia species (D. longispina and D. magna). Three different ponds were used in the characterization of the aquatic system from Cunha Baixa mine: a reference pond (Ref), a mine effluent treatment pond (T), and a mine pit pond (M). Metal analyses performed in the water samples from these ponds showed values that, in some cases, were much higher than maximum recommendable values established (especially Al, Mn) by Portuguese legislation for waters for crop irrigation. Acute toxicity was only observed in the mine pit pond, with EC(50) values of 28.4% and 50.4% for D. longispina and D. magna, respectively. The significant impairment of chronic endpoints, translated in reductions in the population growth rate for both species, gives rise to concerns regarding the potential risks for aquatic zooplanktonic communities, from local receiving waters, potentially exposed to point source discharges of the treated and nontreated effluent from Cunha Baixa uranium mine.

Water toxicity assessment and spatial pollution patterns identification in a Mediterranean River Basin District. Tools for water management and risk analysis.

PubMed

Carafa, Roberta; Faggiano, Leslie; Real, Montserrat; Munné, Antoni; Ginebreda, Antoni; Guasch, Helena; Flo, Monica; Tirapu, Luís; von der Ohe, Peter Carsten

2011-09-15

In compliance with the requirements of the EU Water Framework Directive, monitoring of the ecological and chemical status of Catalan river basins (NE Spain) is carried out by the Catalan Water Agency. The large amount of data collected and the complex relationships among the environmental variables monitored often mislead data interpretation in terms of toxic impact, especially considering that even pollutants at very low concentrations might contribute to the total toxicity. The total dataset of chemical monitoring carried out between 2007 and 2008 (232 sampling stations and 60 pollutants) has been analyzed using sequential advanced modeling techniques. Data on concentrations of contaminants in water were pre-treated in order to calculate the bioavailable fraction, depending on substance properties and local environmental conditions. The resulting values were used to predict the potential impact of toxic substances in complex mixtures on aquatic biota and to identify hot spots. Exposure assessment with Species Sensitivity Distribution (SSD) and mixture toxicity rules were used to compute the multi-substances Potentially Affected Fraction (msPAF). The combined toxicity of the pollutants analyzed in the Catalan surface waters might potentially impact more than 50% of the species in 10% of the sites. In order to understand and visualize the spatial distribution of the toxic risk, Self Organising Map (SOM), based on the Kohonen's Artificial Neural Network (ANN) algorithm, was applied on the output data of these models. Principal Component Analysis (PCA) was performed on top of Neural Network results in order to identify main influential variables which account for the pollution trends. Finally, predicted toxic impacts on biota have been linked and correlated to field data on biological quality indexes using macroinvertebrate and diatom communities (IBMWP and IPS). The methodology presented could represent a suitable tool for water managers in environmental risk

Development of Low-Toxicity Wastewater Stabilization for Spacecraft Water Recovery Systems

NASA Technical Reports Server (NTRS)

Mitchell, Julie L.; Adam, Niklas; Pickering, Karen D.; Alvarez, Giraldo N.

2015-01-01

Wastewater stabilization was an essential component of the spacecraft water cycle. The purpose of stabilizing wastewater was two-fold. First, stabilization prevents the breakdown of urea into ammonia, a toxic gas at high concentrations. Second, it prevents the growth of microorganisms, thereby mitigating hardware and water quality issues due to due biofilm and planktonic growth. Current stabilization techniques involve oxidizers and strong acids (pH=2) such as chromic and sulfuric acid, which are highly toxic and pose a risk to crew health. The purpose of this effort was to explore less toxic stabilization techniques, such as food-grade and commercial care preservatives. Additionally, certain preservatives were tested in the presence of a low-toxicity organic acid. Triplicate 300-milliliter volumes of urine were dosed with a predetermined quantity of stabilizer and stored for two weeks. During that time, pH, total organic carbon (TOC), ammonia, and turbidity were monitored. Those preservatives that showed the lowest visible microbial growth and stable pH were further tested in a six-month stability study. The results of the six-month study are also included in this paper.

Development of Low-Toxicity Urine Stabilization for Spacecraft Water Recovery Systems

NASA Technical Reports Server (NTRS)

Adam, Niklas; Mitchell, Julie L.; Pickering, Karen D.

2012-01-01

Wastewater stabilization is an essential component of the spacecraft water cycle. The purpose of stabilizing wastewater is two-fold. First, stabilization prevents the breakdown of urea into ammonia, a toxic gas at high concentrations. Second, it prevents the growth of microorganisms, thereby mitigating hardware and water quality issues due to due biofilm and planktonic growth. Current stabilization techniques involve oxidizers and strong acids (pH=2) such as chromic and sulfuric acid, which are highly toxic and pose a risk to crew health. The purpose of this effort is to explore less toxic stabilization techniques, such as food-grade and commercial care preservatives. Additionally, certain preservatives were tested in the presence of a low-toxicity organic acid. Triplicate 300-mL volumes of urine were dosed with a predetermined quantity of stabilizer and stored for two weeks. During that time, pH, total organic carbon (TOC), ammonia, and turbidity were monitored. Those preservatives that showed the lowest visible microbial growth and stable pH were further tested in a six-month stability study. The results of the six-month study are also included in this paper.

Development of Low-Toxicity Wastewater Stabilization for Spacecraft Water Recovery Systems

NASA Technical Reports Server (NTRS)

Adam, Niklas; Mitchell, Julie; Pickering, Karen; Carrier, Chris; Vega, Letty; Muirhead, Dean

2014-01-01

Wastewater stabilization was an essential component of the spacecraft water cycle. The purpose of stabilizing wastewater was two-fold. First, stabilization prevents the breakdown of urea into ammonia, a toxic gas at high concentrations. Second, it prevents the growth of microorganisms, thereby mitigating hardware and water quality issues due to due biofilm and planktonic growth. Current stabilization techniques involve oxidizers and strong acids (pH=2) such as chromic and sulfuric acid, which are highly toxic and pose a risk to crew health. The purpose of this effort was to explore less toxic stabilization techniques, such as food-grade and commercial care preservatives. Additionally, certain preservatives were tested in the presence of a low-toxicity organic acid. Triplicate 300-mL volumes of urine were dosed with a predetermined quantity of stabilizer and stored for two weeks. During that time, pH, total organic carbon (TOC), ammonia, and turbidity were monitored. Those preservatives that showed the lowest visible microbial growth and stable pH were further tested in a six-month stability study. The results of the six-month study are also included in this paper.

Sedimentary denitrification: Isotope fractionation and its impact on water column nitrate isotopes

NASA Astrophysics Data System (ADS)

Dähnke, K.; Thamdrup, B.

2012-04-01

The global marine nitrogen cycle is constrained by one major source and two processes that act as nitrogen sinks: nitrogen fixation on the one side and denitrification or anammox on the other. These processes with their respective isotope effecst set the marine nitrate 15N-isotope value to a relatively constant average of 5 per mil. This value can be used to better assess the magnitude of these source and sink terms, but the underlying assumption at present is that sedimentary denitrification, a process responsible for approximately one third of global nitrogen removal, has little to no isotope effect on the water column. We tested this hypothesis in sediment incubations, measuring net denitrification and nitrogen and oxygen stable isotope fractionation in surface sediments from the coastal Baltic Sea (Boknis Eck, Northern Germany). We found tremendously high denitrification rates, and regardless of current paradigms assuming little fractionation during sediment denitrification, we measured fractionation factors of 19 per mil for nitrogen and 11 per mil for oxygen in nitrate. These results potentially challenge the current view of fractionation during sedimentary denitrification and imply that nitrogen budget calculation may need to consider this variability. Furthermore, the ratio of fractionation factors for nitrogen and oxygen is distinct from the 1 : 1 ratio otherwise found in marine systems, and suggests that isotope kinetics of sedimentary denitrification might be entirely different from water column denitrification. Acknowledgements: This work was funded by the German Research Foundation (DFG) and in parts by the Danish National Research Foundation.

THE ACUTE TOXICITY OF MAJOR ION SALTS TO CERIODAPHNIA DUBIA: I. INFLUENCE OF BACKGROUND WATER CHEMISTRY

PubMed Central

Mount, David R.; Erickson, Russell J.; Highland, Terry L.; Hockett, J. Russell; Hoff, Dale J.; Jenson, Correne T.; Norberg-King, Teresa J.; Peterson, Kira N.; Polaske, Zach; Wisniewski, Stephanie

2018-01-01

The ions Na+, K+, Ca2+, Mg2+, Cl−, SO42−, and HCO3−/CO32− (referred to here as “major ions”) are present in all fresh waters and are physiologically required by aquatic organisms, but can increase to harmful levels from a variety of anthropogenic activities. It is also known that the toxicities of major ion salts can vary depending on the concentrations of other ions, and understanding these relationships is key to establishing appropriate environmental limits. In this paper we present a series of experiments with Ceriodaphnia dubia to evaluate the acute toxicity of twelve major ion salts and to determine how toxicity of these salts varies as a function of background water chemistry. All salts except CaSO4 and CaCO3 were acutely toxic below saturation, with the lowest LC50s found for K salts. All ten salts that showed toxicity also showed some degree of reduced toxicity as the ionic content of the background water increased. Experiments that independently varied Ca:Mg ratio, Na:K ratio, Cl:SO4 ratio, and alkalinity/pH demonstrated that Ca concentration was the primary factor influencing the toxicities of Na and Mg salts, while the toxicities of K salts were primarily influenced by the concentration of Na. These experiments also indicated multiple mechanisms of toxicity and suggested important aspects of dosimetry: the toxicities of K, Mg, and Ca salts were best related to the chemical activity of the cation, while the toxicities of Na salts also reflected an influence of the anions and were well correlated with osmolarity. Understanding these relationships between major ion toxicity and background water chemistry should aid in the development of sensible risk assessment and regulatory standards. PMID:27167636

Theoretical Insight into the Biodegradation of Solitary Oil Microdroplets Moving through a Water Column.

PubMed

Kapellos, George E; Paraskeva, Christakis A; Kalogerakis, Nicolas; Doyle, Patrick S

2018-02-12

In the aftermath of oil spills in the sea, clouds of droplets drift into the seawater column and are carried away by sea currents. The fate of the drifting droplets is determined by natural attenuation processes, mainly dissolution into the seawater and biodegradation by oil-degrading microbial communities. Specifically, microbes have developed three fundamental strategies for accessing and assimilating oily substrates. Depending on their affinity for the oily phase and ability to proliferate in multicellular structures, microbes might either attach to the oil surface and directly uptake compounds from the oily phase, or grow suspended in the aqueous phase consuming solubilized oil, or form three-dimensional biofilms over the oil-water interface. In this work, a compound particle model that accounts for all three microbial strategies is developed for the biodegradation of solitary oil microdroplets moving through a water column. Under a set of educated hypotheses, the hydrodynamics and solute transport problems are amenable to analytical solutions and a closed-form correlation is established for the overall dissolution rate as a function of the Thiele modulus, the Biot number and other key parameters. Moreover, two coupled ordinary differential equations are formulated for the evolution of the particle size and used to investigate the impact of the dissolution and biodegradation processes on the droplet shrinking rate.

Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of pesticides in water by C-18 solid-phase extraction and capillary-column gas chromatography/mass spectrometry with selected-ion monitoring

USGS Publications Warehouse

Zaugg, Steven D.; Sandstrom, Mark W.; Smith, Steven G.; Fehlberg, Kevin M.

1995-01-01

A method for the isolation of 41 pesticides and pesticide metabolites in natural-water samples using C-18 solid-phase extraction and determination by capillary-column gas chromatography/mass spectrometry with selected-ion monitoring is described. Water samples are filtered to remove suspended particulate matter and then are pumped through disposable solid-phase extraction columns containing octadecyl-bonded porous silica to extract the pesticides. The columns are dried using carbon dioxide or nitrogen gas, and adsorbed pesticides are removed from the columns by elution with 3.0 milliliters of hexane-isopropanol (3:1). Extracted pesticides are determined by capillary- column gas chromatography/mass spectrometry with selected-ion monitoring of three characteristic ions. The upper concentration limit is 4 micrograms per liter (g/L) for most pesticides, with the exception of widely used corn herbicides--atrazine, alachlor, cyanazine, and metolachlor--which have upper concentration limits of 20 g/L. Single- operator method detection limits in reagent-water samples range from 0.001 to 0.018 g/L. Average short-term single-operator precision in reagent- water samples is 7 percent at the 0.1- and 1.0-g/L levels and 8 percent at the 0.01-g/L level. Mean recoveries in reagent-water samples are 73 percent at the 0.1- and 1.0-g/L levels and 83 percent at the 0.01-g/L level. The estimated holding time for pesticides after extraction on the solid-phase extraction columns was 7 days. An optional on-site extraction procedure allows for samples to be collected and processed at remote sites where it is difficult to ship samples to the laboratory within the recommended pre-extraction holding time.

Communities of nirS-type denitrifiers in the water column of the oxygen minimum zone in the eastern South Pacific.

PubMed

Castro-González, Maribeb; Braker, Gesche; Farías, Laura; Ulloa, Osvaldo

2005-09-01

The major sites of water column denitrification in the ocean are oxygen minimum zones (OMZ), such as one in the eastern South Pacific (ESP). To understand the structure of denitrifying communities in the OMZ off Chile, denitrifier communities at two sites in the Chilean OMZ (Antofagasta and Iquique) and at different water depths were explored by terminal restriction fragment length polymorphism analysis and cloning of polymerase chain reaction (PCR)-amplified nirS genes. NirS is a functional marker gene for denitrification encoding cytochrome cd1-containing nitrite reductase, which catalyses the reduction of nitrite to nitric oxide, the key step in denitrification. Major differences were found between communities from the two geographic locations. Shifts in community structure occurred along a biogeochemical gradient at Antofagasta. Canonical correspondence analysis indicated that O2, NO3-, NO2- and depth were important environmental factors governing these communities along the biogeochemical gradient in the water column. Phylogenetic analysis grouped the majority of clones from the ESP in distinct clusters of genes from presumably novel and yet uncultivated denitrifers. These nirS clusters were distantly related to those found in the water column of the Arabian Sea but the phylogenetic distance was even higher compared with environmental sequences from marine sediments or any other habitat. This finding suggests similar environmental conditions trigger the development of denitrifiers with related nirS genotypes despite large geographic distances.

Coastal circulation and water column properties off Kalaupapa National Historical Park, Molokai, Hawaii, 2008-2010

USGS Publications Warehouse

Storlazzi, Curt D.; Presto, Katherine; Brown, Eric K.

2011-01-01

More than 2.2 million measurements of oceanographic forcing and the resulting water-column properties were made off U.S. National Park Service's Kalaupapa National Historical Park on the north shore of Molokai, Hawaii, between 2008 and 2010 to understand the role of oceanographic processes on the health and sustainability of the area's marine resources. The tides off the Kalaupapa Peninsula are mixed semidiurnal. The wave climate is dominated by two end-members: large northwest Pacific winter swell that directly impacts the study site, and smaller, shorter-period northeast trade-wind waves that have to refract around the peninsula, resulting in a more northerly direction before propagating over the study site. The currents primarily are alongshore and are faster at the surface than close to the seabed; large wave events, however, tend to drive flow in a more cross-shore orientation. The tidal currents flood to the north and ebb to the south. The waters off the peninsula appear to be a mix of cooler, more saline, deeper oceanic waters and shallow, warmer, lower-salinity nearshore waters, with intermittent injections of freshwater, generally during the winters. Overall, the turbidity levels were low, except during large wave events. The low overall turbidity levels and rapid return to pre-event background levels following the cessation of forcing suggest that there is little fine-grained material. Large wave events likely inhibit the settlement of fine-grained sediment at the site. A number of phenomena were observed that indicate the complexity of coastal circulation and water-column properties in the area and may help scientists and resource managers to better understand the implications of the processes on marine ecosystem health.

Acute and chronic toxicity of sodium sulfate to four freshwater organisms in water-only exposures

USGS Publications Warehouse

Wang, Ning; Consbrock, Rebecca A.; Ingersoll, Christopher G.; Hardesty, Douglas K.; Brumbaugh, William G.; Hammer, Edward J.; Bauer, Candice R.; Mount, David R.

2016-01-01

The acute and chronic toxicity of sulfate (tested as sodium sulfate) was determined in diluted well water (hardness of 100 mg/L and pH 8.2) with a cladoceran (Ceriodaphnia dubia; 2-d and 7-d exposures), a midge (Chironomus dilutus; 4-d and 41-d exposures), a unionid mussel (pink mucket, Lampsilis abrupta; 4-d and 28-d exposures), and a fish (fathead minnow, Pimephales promelas; 4-d and 34-d exposures). Among the 4 species, the cladoceran and mussel were acutely more sensitive to sulfate than the midge and fathead minnow, whereas the fathead minnow was chronically more sensitive than the other 3 species. Acute-to-chronic ratios ranged from 2.34 to 5.68 for the 3 invertebrates but were as high as 12.69 for the fish. The fathead minnow was highly sensitive to sulfate during the transitional period from embryo development to hatching in the diluted well water, and thus, additional short-term (7- to 14-d) sulfate toxicity tests were conducted starting with embryonic fathead minnow in test waters with different ionic compositions at a water hardness of 100 mg/L. Increasing chloride in test water from 10 mg Cl/L to 25 mg Cl/L did not influence sulfate toxicity to the fish, whereas increasing potassium in test water from 1mg K/L to 3mg K/L substantially reduced the toxicity of sulfate. The results indicate that both acute and chronic sulfate toxicity data, and the influence of potassium on sulfate toxicity to fish embryos, need to be considered when environmental guidance values for sulfate are developed or refined.

Function of Serum Complement in Drinking Water Arsenic Toxicity

PubMed Central

Islam, Laila N.; Zahid, M. Shamim Hasan; Nabi, A. H. M. Nurun; Hossain, Mahmud

2012-01-01

Serum complement function was evaluated in 125 affected subjects suffering from drinking water arsenic toxicity. Their mean duration of exposure was 7.4 ± 5.3 yrs, and the levels of arsenic in drinking water and urine samples were 216 ± 211 and 223 ± 302 μg/L, respectively. The mean bactericidal activity of complement from the arsenic patients was 92% and that in the unexposed controls was 99% (P < 0.01), but heat-inactivated serum showed slightly elevated activity than in controls. In patients, the mean complement C3 was 1.56 g/L, and C4 was 0.29 g/L compared to 1.68 g/L and 0.25 g/L, respectively, in the controls. The mean IgG in the arsenic patients was 24.3 g/L that was highly significantly elevated (P < 0.001). Arsenic patients showed a significant direct correlation between C3 and bactericidal activity (P = 0.014). Elevated levels of C4 indicated underutilization and possibly impaired activity of the classical complement pathway. We conclude reduced function of serum complement in drinking water arsenic toxicity. PMID:22545044

Bubble Plumes at NW Rota-1 Submarine Volcano, Mariana Arc: Visualization and Analysis of Multibeam Water Column Data

NASA Astrophysics Data System (ADS)

Merle, S. G.; Chadwick, W. W.; Embley, R. W.; Doucet, M.

2012-12-01

During a March 2010 expedition to NW Rota-1 submarine volcano in the Mariana arc a new EM122 multibeam sonar system on the R/V Kilo Moana was used to repeatedly image bubble plumes in the water column over the volcano. The EM122 (12 kHz) system collects seafloor bathymetry and backscatter data, as well as acoustic return water column data. Previous expeditions to NW Rota-1 have included seafloor mapping / CTD tow-yo surveys and remotely operated vehicle (ROV) dives in 2004, 2005, 2006 and 2009. Much of the focus has been on the one main eruptive vent, Brimstone, located on the south side of the summit at a depth of ~440m, which has been persistently active during all ROV visits. Extensive degassing of CO2 bubbles have been observed by the ROV during frequent eruptive bursts from the vent. Between expeditions in April 2009 and March 2010 a major eruption and landslide occurred at NW Rota-1. ROV dives in 2010 revealed that after the landslide the eruptive vent had been reorganized from a single site to a line of vents. Brimstone vent was still active, but 4 other new eruptive vents had also emerged in a NW/SE line below the summit extending ~100 m from the westernmost to easternmost vents. During the ROV dives, the eruptive vents were observed to turn on and off from day to day and hour to hour. Throughout the 2010 expedition numerous passes were made over the volcano summit to image the bubble plumes above the eruptive vents in the water column, in order to capture the variability of the plumes over time and to relate them to the eruptive output of the volcano. The mid-water sonar data set totals >95 hours of observations over a 12-day period. Generally, the ship drove repeatedly over the eruptive vents at a range of ship speeds (0.5-4 knots) and headings. In addition, some mid-water data was collected during three ROV dives when the ship was stationary over the vents. We used the FMMidwater software program (part of QPS Fledermaus) to visualize and analyze the data

Sunlight Controls Water Column Processing of Carbon in Arctic Freshwaters

NASA Astrophysics Data System (ADS)

Cory, R. M.; Ward, C. P.; Crump, B. C.; Kling, G. W.

2014-12-01

Carbon (C) in thawing permafrost soils may have global impacts on climate change, yet controls on its processing and fate are poorly understood. The dominant fate of dissolved organic C (DOC) released from soils to inland waters is either complete oxidation to CO2 or partial oxidation and river export to oceans. Both processes are most often attributed to bacterial respiration, but we recently showed that photochemical oxidation exceeds rates of respiration and accounts for 70-95% of total DOC processed in the water column of arctic lakes and rivers. While the overall dominance of photochemical processing in streams and lakes remained, the fate of DOC varied consistently by water type. In small streams DOC was mainly mineralized by sunlight to CO2, while in lakes the main fate of DOC was partial photo-oxidation. Large rivers were intermediate between these end members, and photo-mineralization to CO2 was about equal to or less than partial photo-oxidation. We suggest this pattern is a result of light-exposure history, where DOC leached from soils into headwater streams has little prior light exposure and is labile to complete photo-oxidation, but as light exposure increases moving downstream and into lakes with longer residence times the DOC photo-lability declines. Thus as easily photo-mineralized moieties are removed, DOC fate shifts toward partial photo-oxidation and downstream export in rivers and lakes. At the basin scale, photochemical processing of DOC is about one third of the total CO2 released from surface waters, and is thus an important, newly measured component of the Arctic C budget. We also suggest that these photochemical transformations of DOC will occur in any shallow surface water, and could be important for better understanding inland water carbon cycling.

Photoenhanced toxicity of weathered crude oil in sediment and water to larval zebrafish

EPA Science Inventory

Solar radiation exposure can increase the toxicity of bioaccumulated oil compounds in a diversity of aquatic species. We investigated the photoenhanced toxicity of weathered South Louisiana crude oil in sediment and water accommodated fractions (WAF) to larval zebrafish. Larvae w...

Intense molybdenum accumulation in sediments underneath a nitrogenous water column and implications for the reconstruction of paleo-redox conditions based on molybdenum isotopes

NASA Astrophysics Data System (ADS)

Scholz, Florian; Siebert, Christopher; Dale, Andrew W.; Frank, Martin

2017-09-01

The concentration and isotope composition of molybdenum (Mo) in sediments and sedimentary rocks are widely used proxies for anoxic conditions in the water column of paleo-marine systems. While the mechanisms leading to Mo fixation in modern restricted basins with anoxic and sulfidic (euxinic) conditions are reasonably well constrained, few studies have focused on Mo cycling in the context of open-marine anoxia. Here we present Mo data for water column particulate matter, modern surface sediments and a paleo-record covering the last 140,000 years from the Peruvian continental margin. Mo concentrations in late Holocene and Eemian (penultimate interglacial) shelf sediments off Peru range from ∼70 to 100 μg g-1, an extent of Mo enrichment that is thought to be indicative of (and limited to) euxinic systems. To investigate if this putative anomaly could be related to the occasional occurrence of sulfidic conditions in the water column overlying the Peruvian shelf, we compared trace metal (Mo, vanadium, uranium) enrichments in particulate matter from oxic, nitrate-reducing (nitrogenous) and sulfidic water masses. Coincident enrichments of iron (Fe) (oxyhydr)oxides and Mo in the nitrogenous water column as well as co-variation of dissolved Fe and Mo in the sediment pore water suggest that Mo is delivered to the sediment surface by Fe (oxyhydr)oxides. Most of these precipitate in the anoxic-nitrogenous water column due to oxidation of sediment-derived dissolved Fe with nitrate as a terminal electron acceptor. Upon reductive dissolution in the surface sediment, a fraction of the Fe and Mo is re-precipitated through interaction with pore water sulfide. The Fe- and nitrate-dependent mechanism of Mo accumulation proposed here is supported by the sedimentary Mo isotope composition, which is consistent with Mo adsorption onto Fe (oxyhydr)oxides. Trace metal co-variation patterns as well as Mo and nitrogen isotope systematics suggest that the same mechanism of Mo delivery

40 CFR 129.6 - Adjustment of effluent standard for presence of toxic pollutant in the intake water.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 21 2010-07-01 2010-07-01 false Adjustment of effluent standard for presence of toxic pollutant in the intake water. 129.6 Section 129.6 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS TOXIC POLLUTANT EFFLUENT STANDARDS Toxic Pollutant Effluent Standards and Prohibitions § 129.6...

40 CFR 129.6 - Adjustment of effluent standard for presence of toxic pollutant in the intake water.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 22 2011-07-01 2011-07-01 false Adjustment of effluent standard for presence of toxic pollutant in the intake water. 129.6 Section 129.6 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS TOXIC POLLUTANT EFFLUENT STANDARDS Toxic Pollutant Effluent Standards and Prohibitions § 129.6...

Comparison of GOME-2/Metop total column water vapour with ground-based and in situ measurements

NASA Astrophysics Data System (ADS)

Kalakoski, N.; Kujanpää, J.; Sofieva, V.; Tamminen, J.; Grossi, M.; Valks, P.

2014-12-01

Total column water vapour product from the Global Ozone Monitoring Experiment-2 on board Metop-A and Metop-B satellites (GOME-2/Metop-A and GOME-2/Metop-B) produced by the Satellite Application Facility on Ozone and Atmospheric Chemistry Monitoring (O3M SAF) is compared with co-located radiosonde and Global Positioning System (GPS) observations. The comparisons are performed using recently reprocessed data by the GOME Data Processor (GDP) version 4.7. The comparisons are performed for the period of January 2007-July 2013 (GOME-2A) and from December 2012 to July 2013 (GOME-2B). Radiosonde data are from the Integrated Global Radiosonde Archive (IGRA) maintained by National Climatic Data Center (NCDC) and screened for soundings with incomplete tropospheric column. Ground-based GPS observations from COSMIC/SuomiNet network are used as the second independent data source. Good general agreement between GOME-2 and the ground-based observations is found. The median relative difference of GOME-2 to radiosonde observations is -2.7% for GOME-2A and -0.3% for GOME-2B. Against GPS observations, the median relative differences are 4.9 and 3.2% for GOME-2A and B, respectively. For water vapour total columns below 10 kg m-2, large wet biases are observed, especially against GPS observations. Conversely, at values above 50 kg m-2, GOME-2 generally underestimates both ground-based observations.

Methanotrophy within the water column of a large meromictic tropical lake (Lake Kivu, East Africa)

NASA Astrophysics Data System (ADS)

Morana, C.; Borges, A. V.; Roland, F. A. E.; Darchambeau, F.; Descy, J.-P.; Bouillon, S.

2015-04-01

The permanently stratified Lake Kivu is one of the largest freshwater reservoirs of dissolved methane (CH4) on Earth. Yet CH4 emissions from its surface to the atmosphere have been estimated to be 2 orders of magnitude lower than the CH4 upward flux to the mixed layer, suggesting that microbial CH4 oxidation is an important process within the water column. A combination of natural abundance stable carbon isotope analysis (δ13C) of several carbon pools and 13CH4-labelling experiments was carried out during the rainy and dry season to quantify (i) the contribution of CH4-derived carbon to the biomass, (ii) methanotrophic bacterial production (MBP), and (iii) methanotrophic bacterial growth efficiency (MBGE), defined as the ratio between MBP and gross CH4 oxidation. We also investigated the distribution and the δ13C of specific phospholipid fatty acids (PLFAs), used as biomarkers for aerobic methanotrophs. Maximal MBP rates were measured in the oxycline, suggesting that CH4 oxidation was mainly driven by oxic processes. Moreover, our data revealed that methanotrophic organisms in the water column oxidized most of the upward flux of CH4, and that a significant amount of CH4-derived carbon was incorporated into the microbial biomass in the oxycline. The MBGE was variable (2-50%) and negatively related to CH4 : O2 molar ratios. Thus, a comparatively smaller fraction of CH4-derived carbon was incorporated into the cellular biomass in deeper waters, at the bottom of the oxycline where oxygen was scarce. The aerobic methanotrophic community was clearly dominated by type I methanotrophs and no evidence was found for an active involvement of type II methanotrophs in CH4 oxidation in Lake Kivu, based on fatty acids analyses. Vertically integrated over the water column, the MBP was equivalent to 16-60% of the average phytoplankton particulate primary production. This relatively high magnitude of MBP, and the substantial contribution of CH4-derived carbon to the overall

Pore-Water Carbonate and Phosphate As Predictors of Arsenate Toxicity in Soil.

PubMed

Lamb, Dane T; Kader, Mohammed; Wang, Liang; Choppala, Girish; Rahman, Mohammad Mahmudur; Megharaj, Mallavarapu; Naidu, Ravi

2016-12-06

Phytotoxicity of inorganic contaminants is influenced by the presence of competing ions at the site of uptake. In this study, interaction of soil pore-water constituents with arsenate toxicity was investigated in cucumber (Cucumis sativa L) using 10 contrasting soils. Arsenate phytotoxicity was shown to be related to soluble carbonate and phosphate. The data indicated that dissolved phosphate and carbonate had an antagonistic impact on arsenate toxicity to cucumber. To predict arsenate phytotoxicity in soils with a diverse range of soil solution properties, both carbonate and phosphate were required. The relationship between arsenic and pore-water toxicity parameters was established initially using multiple regression. In addition, based on the relationship with carbonate and phosphate we successively applied a terrestrial biotic ligand-like model (BLM) including carbonate and phosphate. Estimated effective concentrations from the BLM-like parametrization were strongly correlated to measured arsenate values in pore-water (R 2 = 0.76, P < 0.001). The data indicates that an ion interaction model similar to the BLM for arsenate is possible, potentially improving current risk assessments at arsenic and co-contaminated soils.

Alkaline phosphatase activity of water column fractions and seagrass in a tropical carbonate estuary, Florida Bay

NASA Astrophysics Data System (ADS)

Koch, Marguerite S.; Kletou, Demetris C.; Tursi, Rosanna

2009-08-01

Few phosphorus-depleted coastal ecosystems have been examined for their ability to hydrolyze phosphomonoesters. We examined seasonal (August 2006-April 2007) alkaline phosphatase activity in Florida Bay, a phosphorus-limited shallow estuary, using fluorescent substrate at low concentrations (≤2.0 μM). In situ dissolved inorganic and organic phosphorus levels and phosphomonoester concentrations were also determined. Water column alkaline phosphatase activity was partitioned into two particulate size fractions (>1.2 and 0.2-1.2 μm) and freely dissolved enzymes (<0.2 μm). Water column alkaline phosphatase activity was also compared to leaf and epiphyte activity of the dominant tropical seagrass Thalassia testudinum. Our results indicate: (1) potential alkaline phosphatase activity in Florida Bay is high compared to other marine ecosystems, resulting in rapid phosphomonoester turnover times (˜2 h). (2) Water column alkaline phosphatase activity dominates, and is split equally between particulate and dissolved fractions. (3) Alkaline phosphatase activity was highest during cyanobacterial blooms, but not when normalized to chl a. These results suggest that dissolved, heterotrophic and autotrophic alkaline phosphatase activity is stimulated by phytoplankton blooms. (4) The dissolved alkaline phosphatase activity is relatively constant, while the particulate activity is seasonally and spatially dynamic, typically associated with phytoplankton blooms. (5) Phosphomonoester concentrations throughout the bay are low, even though potential hydrolysis rates are high. We propose that bioavailable dissolved organic P is hydrolyzed by dissolved and microbial alkaline phosphatase enzymes in Florida Bay. High alkaline phosphatase activity in the bay is also promoted by long hydraulic residence times. This background activity is primarily driven by carbon and phosphorus limitation of microorganisms, and regeneration of enzymes associated with cell lysis. Pulses of inorganic

Influence of ozonation and biodegradation on toxicity of industrial textile wastewater.

PubMed

Paździor, Katarzyna; Wrębiak, Julita; Klepacz-Smółka, Anna; Gmurek, Marta; Bilińska, Lucyna; Kos, Lech; Sójka-Ledakowicz, Jadwiga; Ledakowicz, Stanisław

2017-06-15

The textile industry demands huge volumes of high quality water which converts into wastewater contaminated by wide spectrum of chemicals. Estimation of textile wastewater influence on the aquatic systems is a very important issue. Therefore, closing of the water cycle within the factories is a promising method of decreasing its environmental impact as well as operational costs. Taking both reasons into account, the aim of this work was to establish the acute toxicity of the textile wastewater before and after separate chemical, biological as well as combined chemical-biological treatment. For the first time the effects of three different combinations of chemical and biological methods were investigated. The acute toxicity analysis were evaluated using the Microtox ® toxicity test. Ozonation in two reactors of working volume 1 dm 3 (stirred cell) and 20 dm 3 (bubble column) were tested as chemical process, while biodegradation was conducted in two, different systems - Sequence Batch Reactors (SBR; working volume 1.5 dm 3 ) and Horizontal Continuous Flow Bioreactor (HCFB; working volume 12 dm 3 ). The untreated wastewater had the highest toxicity (EC50 value in range: 3-6%). Ozonation caused lower reduction of the toxicity than biodegradation. In the system with SBR the best results were obtained for the biodegradation followed by the ozonation and additional biodegradation - 96% of the toxicity removal. In the second system (with HCFB) two-stage treatment (biodegradation followed by the ozonation) led to the highest toxicity reduction (98%). Copyright © 2016 Elsevier Ltd. All rights reserved.

Strains of toxic and harmful microalgae, from waste water, marine, brackish and fresh water.

PubMed

Rodríguez-Palacio, M C; Crisóstomo-Vázquez, L; Alvarez-Hernández, S; Lozano-Ramírez, C

2012-01-01

Some microalgae are economically important in Mexico and the world because they can be potentially toxic. Algal explosive population growths are named harmful algal blooms and are frequently recorded in Mexico. The authors set up potentially toxic microalgae cultures from the Gulf of Mexico (Garrapatas tideland, Barberena river, Carpintero lagoon in Tamaulipas State; Chalchoapan and Catemaco lakes in Veracruz State), from the Mexican Pacific Ocean, Guerrero, Colima and Michoacán States, and from interior water bodies such as Vicente Aguirre dam, Chapultepec lake and several waste water treatment plants. This research is about the diversity and abundance of phytoplankton in relation a specific site because of harmful algal bloom events. Microalgae cultures are useful in order to solve taxonomic problems, to know life cycles, molecular studies, for the study of toxic species, and the isolation of useful metabolites. The cultures for this research are clonal, non-axenic, semi-continuous, 12:12 light/dark photoperiod, 20 ± 1 °C temperature and 90.5 µmol m(-2)s(-1) illumination. Four different culture media were used. This collection is open to the worldwide scientific community as a source of organisms in controlled conditions that can be used as a useful tool for microalgae research work.

Column-to-column packing variation of disposable pre-packed columns for protein chromatography.

PubMed

Schweiger, Susanne; Hinterberger, Stephan; Jungbauer, Alois

2017-12-08

In the biopharmaceutical industry, pre-packed columns are the standard for process development, but they must be qualified before use in experimental studies to confirm the required performance of the packed bed. Column qualification is commonly done by pulse response experiments and depends highly on the experimental testing conditions. Additionally, the peak analysis method, the variation in the 3D packing structure of the bed, and the measurement precision of the workstation influence the outcome of qualification runs. While a full body of literature on these factors is available for HPLC columns, no comparable studies exist for preparative columns for protein chromatography. We quantified the influence of these parameters for commercially available pre-packed and self-packed columns of disposable and non-disposable design. Pulse response experiments were performed on 105 preparative chromatography columns with volumes of 0.2-20ml. The analyte acetone was studied at six different superficial velocities (30, 60, 100, 150, 250 and 500cm/h). The column-to-column packing variation between disposable pre-packed columns of different diameter-length combinations varied by 10-15%, which was acceptable for the intended use. The column-to-column variation cannot be explained by the packing density, but is interpreted as a difference in particle arrangement in the column. Since it was possible to determine differences in the column-to-column performance, we concluded that the columns were well-packed. The measurement precision of the chromatography workstation was independent of the column volume and was in a range of±0.01ml for the first peak moment and±0.007 ml 2 for the second moment. The measurement precision must be considered for small columns in the range of 2ml or less. The efficiency of disposable pre-packed columns was equal or better than that of self-packed columns. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

Comparison of Passive Sampling Devices for Measuring Dissolved PCBs in the Water Column of a Marine Superfund Site

EPA Science Inventory

The presence of contaminated sediments in aquatic environments results in several potential sources of ecological risk. These risks include the release of contaminants into the water column causing exposure to pelagic organisms. Possible adverse biological effects of this exposu...

Water ice cloud property retrievals at Mars with OMEGA:Spatial distribution and column mass

NASA Astrophysics Data System (ADS)

Olsen, Kevin S.; Madeleine, Jean-Baptiste; Szantai, Andre; Audouard, Joachim; Geminale, Anna; Altieri, Francesca; Bellucci, Giancarlo; Montabone, Luca; Wolff, Michael J.; Forget, Francois

2017-04-01

Spectral images of Mars recorded by OMEGA (Observatoire pour la Minéralogie, l'Eau, les Glaces et l'Activité) on Mars Express can be used to deduce the mean effective radius (r_eff) and optical depth (τ_i) of water ice particles in clouds. Using new data sets for a priori surface temperature, vertical profiles of atmospheric temperature, dust opacity, and multi-spectral surface albedo, we have analyzed over 40 OMEGA image cubes over the Tharsis, Arabia, and Syrtis Major quadrangles, and mapped the spatial distribution of r_eff, τ_i, and water ice column mass. We also explored the parameter space of r_eff and τ_i, which are inversely proportional, and the ice cloud index (ICI), which is the ratio of the reflectance at 3.4 and 3.52 μm, and indicates the thickness of water ice clouds. We found that the ICI, trivial to calculate for OMEGA image cubes, can be a proxy for column mass, which is very expensive to compute, requiring accurate retrievals of surface albedo, r_eff, and τ_i. Observing the spatial distribution, we find that within each cloud system, r_eff varies about a mean of 2.1 μm, that τi is closely related to r_eff, and that the values allowed for τ_i, given r_eff, are related to the ICI. We also observe areas where our retrieval detects very thin clouds made of very large particles (mean of 12.5 μm), which are still under investigation.

Gradient HPLC of antibiotics in urine, ground water, chicken muscle, hospital wastewater, and pharmaceutical samples using C-18 and RP-amide columns.

PubMed

Kumar, Ashwini; Kumar Malik, Ashok; Kumar Tewary, Dhananjay; Singh, Baldev

2008-02-01

A simple and highly sensitive high pressure liquid chromatographic (HPLC-UV) method has been developed for the determination of ofloxacin, lomefloxacin, cinoxacin, and nalidixic acid, in mobile phase citrate buffer (0.001 M) of pH 4.5 prepared in water (X), methanol (Y), and ACN (Z) using gradient at a flow rate of 1.0 mL/min by direct UV absorbance detection at lambda = 280 nm. Separation of analytes was studied on the C-18 and RP-amide columns and best results were observed on the RP-amide column with LODs (3.3 x S/m) 0.89, 0.55, 0.67, and 1.41 ng/mL for ofloxacin, lomefloxacin, cinoxacin, and nalidixic acid, respectively, and better RSD than the C-18 column. The recovery of Fluoroquinolones (FQs) in urine, ground water, hospital wastewater, and chicken muscle using this method is more than 90%. The method was successfully applied to the analysis of ofloxacin, lomefloxacin, cinoxacin, and nalidixic acid in urine, ground water, pharmaceutical dosage forms, hospital wastewater, and chicken muscle.

Retrieval of water vapor column abundance and aerosol properties from ChemCam passive sky spectroscopy

NASA Astrophysics Data System (ADS)

McConnochie, Timothy H.; Smith, Michael D.; Wolff, Michael J.; Bender, Steve; Lemmon, Mark; Wiens, Roger C.; Maurice, Sylvestre; Gasnault, Olivier; Lasue, Jeremie; Meslin, Pierre-Yves; Harri, Ari-Matti; Genzer, Maria; Kemppinen, Osku; Martínez, Germán M.; DeFlores, Lauren; Blaney, Diana; Johnson, Jeffrey R.; Bell, James F.

2018-06-01

We derive water vapor column abundances and aerosol properties from Mars Science Laboratory (MSL) ChemCam passive mode observations of scattered sky light. This paper covers the methodology and initial results for water vapor and also provides preliminary results for aerosols. The data set presented here includes the results of 113 observations spanning from Mars Year 31 Ls = 291° (March 30, 2013) to Mars Year 33 Ls= 127° (March 24, 2016). Each ChemCam passive sky observation acquires spectra at two different elevation angles. We fit these spectra with a discrete-ordinates multiple scattering radiative transfer model, using the correlated-k approximation for gas absorption bands. The retrieval proceeds by first fitting the continuum of the ratio of the two elevation angles to solve for aerosol properties, and then fitting the continuum-removed ratio to solve for gas abundances. The final step of the retrieval makes use of the observed CO2 absorptions and the known CO2 abundance to correct the retrieved water vapor abundance for the effects of the vertical distribution of scattering aerosols and to derive an aerosol scale height parameter. Our water vapor results give water vapor column abundance with a precision of ±0.6 precipitable microns and systematic errors no larger than ±0.3 precipitable microns, assuming uniform vertical mixing. The ChemCam-retrieved water abundances show, with only a few exceptions, the same seasonal behavior and the same timing of seasonal minima and maxima as the TES, CRISM, and REMS-H data sets that we compare them to. However ChemCam-retrieved water abundances are generally lower than zonal and regional scale from-orbit water vapor data, while at the same time being significantly larger than pre-dawn REMS-H abundances. Pending further analysis of REMS-H volume mixing ratio uncertainties, the differences between ChemCam and REMS-H pre-dawn mixing ratios appear to be much too large to be explained by large scale circulations and thus

The European Multidisciplinary Seafloor and Water-column Observatory Consortium (EMSO-ERIC): Impact, Progress, and Plans.

NASA Astrophysics Data System (ADS)

Best, Mairi

2016-04-01

EMSO is forging ahead through the next challenge in Earth-Ocean Science: How to co-ordinate ocean data acquisition, analysis and response across provincial, national, regional, and global scales. EMSO provides power, communications, sensors, and data infrastructure for continuous, high resolution, (near)-real-time, interactive ocean observations across a truly multi- and interdisciplinary range of research areas including biology, geology, chemistry, physics, engineering, and computer science; from polar to tropical environments, through the water column down to the abyss. 11 deep sea and 4 shallow nodes span from Arctic through the Atlantic and Mediterranean, to the Black Sea. The EMSO Preparatory Phase (FP7) project led to the Interim phase (involving 13 countries) of forming the legal entity: the EMSO European Research Infrastructure Consortium (EMSO-ERIC). The open user community is through ESONET-Vi (European Seafloor Observatory NETwork - The Vision), following on the extensive scientific community planning contributions of the ESONET-NoE (FP6) project. The further progress made through the FixO3 project (FP7) will also benefit the development of this shared infrastructure. Coordination among nodes is being strengthened through the EMSOdev project (H2020) which will produce the EMSO Generic Instrument Module (EGIM) - standardised observations of temperature, pressure, salinity, dissolved oxygen, turbidity, chlorophyll fluorescence, currents, passive acoustics, pH, pCO2, and nutrients. Early installations are now being upgraded; for example in October 2015 EMSO-France deployed a second cable and junction box serving the Ligurian Sea Node in order to monitor slope stability offshore Nice; in 2016 the EMSO Azores Node will receive a major upgrade that will double its observing capacity; for the Ionian Sea Node the Capo Passero site will be installed and the Catania site will be upgraded. Significant findings are already coming in; for example high frequency

Toxicity of Water Accommodated Fractions of Estonian Shale Fuel Oils to Aquatic Organisms.

PubMed

Blinova, Irina; Kanarbik, Liina; Sihtmäe, Mariliis; Kahru, Anne

2016-02-01

Estonia is the worldwide leading producer of the fuel oils from the oil shale. We evaluated the ecotoxicity of water accommodated fraction (WAF) of two Estonian shale fuel oils ("VKG D" and "VKG sweet") to aquatic species belonging to different trophic levels (marine bacteria, freshwater crustaceans and aquatic plants). Artificial fresh water and natural lake water were used to prepare WAFs. "VKG sweet" (lower density) proved more toxic to aquatic species than "VKG D" (higher density). Our data indicate that though shale oils were very toxic to crustaceans, the short-term exposure of Daphnia magna to sub-lethal concentrations of shale fuel oils WAFs may increase the reproductive potential of survived organisms. The weak correlation between measured chemical parameters (C10-C40 hydrocarbons and sum of 16 PAHs) and WAF's toxicity to studied species indicates that such integrated chemical parameters are not very informative for prediction of shale fuel oils ecotoxicity.

An evaluation of the residual toxicity and chemistry of a sodium hydroxide-based ballast water treatment system for freshwater ships.

PubMed

Elskus, Adria A; Ingersoll, Christopher G; Kemble, Nile E; Echols, Kathy R; Brumbaugh, William G; Henquinet, Jeffrey W; Watten, Barnaby J

2015-06-01

Nonnative organisms in the ballast water of freshwater ships must be killed to prevent the spread of invasive species. The ideal ballast water treatment system (BWTS) would kill 100% of ballast water organisms with minimal residual toxicity to organisms in receiving waters. In the present study, the residual toxicity and chemistry of a BWTS was evaluated. Sodium hydroxide was added to elevate pH to >11.5 to kill ballast water organisms, then reduced to pH <9 by sparging with wet-scrubbed diesel exhaust (the source of CO2 ). Cladocerans (Ceriodaphnia dubia), amphipods (Hyalella azteca), and fathead minnows (Pimephales promelas) were exposed for 2 d to BWTS water under an air atmosphere (pH drifted to ≥9) or a 2.5% CO2 atmosphere (pH 7.5-8.2), then transferred to control water for 5 d to assess potential delayed toxicity. Chemical concentrations in the BWTS water met vessel discharge guidelines with the exception of concentrations of copper. There was little to no residual toxicity to cladocerans or fish, but the BWTS water was toxic to amphipods. Maintaining a neutral pH and diluting BWTS water by 50% eliminated toxicity to the amphipods. The toxicity of BWTS water would likely be minimal because of rapid dilution in the receiving water, with subsurface release likely preventing pH rise. This BWTS has the potential to become a viable method for treating ballast water released into freshwater systems. © 2015 SETAC.

An evaluation of the residual toxicity and chemistry of a sodium hydroxide-based ballast water treatment system for freshwater ships

USGS Publications Warehouse

Elskus, Adria; Ingersoll, Christopher G.; Kemble, Nile E.; Echols, Kathy R.; Brumbaugh, William G.; Henquinet, Jeffrey; Watten, Barnaby J.

2015-01-01

Nonnative organisms in the ballast water of freshwater ships must be killed to prevent the spread of invasive species. The ideal ballast water treatment system (BWTS) would kill 100% of ballast water organisms with minimal residual toxicity to organisms in receiving waters. In the present study, the residual toxicity and chemistry of a BWTS was evaluated. Sodium hydroxide was added to elevate pH to >11.5 to kill ballast water organisms, then reduced to pH <9 by sparging with wet-scrubbed diesel exhaust (the source of CO2). Cladocerans (Ceriodaphnia dubia), amphipods (Hyalella azteca), and fathead minnows (Pimephales promelas) were exposed for 2 d to BWTS water under an air atmosphere (pH drifted to ≥9) or a 2.5% CO2 atmosphere (pH 7.5–8.2), then transferred to control water for 5 d to assess potential delayed toxicity. Chemical concentrations in the BWTS water met vessel discharge guidelines with the exception of concentrations of copper. There was little to no residual toxicity to cladocerans or fish, but the BWTS water was toxic to amphipods. Maintaining a neutral pH and diluting BWTS water by 50% eliminated toxicity to the amphipods. The toxicity of BWTS water would likely be minimal because of rapid dilution in the receiving water, with subsurface release likely preventing pH rise. This BWTS has the potential to become a viable method for treating ballast water released into freshwater systems.

Determination of toxic metals in drinking water sources in the Chief Albert Luthuli Local Municipality in Mpumalanga, South Africa

NASA Astrophysics Data System (ADS)

Nthunya, Lebea N.; Masheane, Monaheng L.; Malinga, Soraya P.; Nxumalo, Edward N.; Mamba, Bhekie B.; Mhlanga, Sabelo D.

2017-08-01

This study was conducted to determine the presence and levels of toxic metals on selected water sources in a rural community in Lochiel, South Africa. Collection of water samples from identified drinking water sources (open wells, community tanks, water treatment works and boreholes) was done in all seasons of the year (winter, spring, summer and autumn) between 2014 and 2015. The concentrations of identified toxic metals (cobalt, chromium, copper, lead, zinc, manganese and iron) were measured using ICP-OES. Some water sources were found to contain concentrations of toxic metals at levels slightly higher than USEPA, WHO and SANS241 set limits (e.g. manganese and cobalt), while others were found to be within the acceptable limits. This suggested that the residents residing in locations that have water sources containing toxic metals at the concentrations above the set limits are at risk and susceptible to suffer diseases caused by these toxic metals. The side effects of the metals may not be acute; however prolonged exposure to the toxic metals may result in detrimental effects since they are known to bioaccumulate in the body.

The effects of carbide column to swelling potential and Atterberg limit on expansive soil with column to soil drainage

NASA Astrophysics Data System (ADS)

Muamar Rifa'i, Alfian; Setiawan, Bambang; Djarwanti, Noegroho

2017-12-01

The expansive soil is soil that has a potential for swelling-shrinking due to changes in water content. Such behavior can exert enough force on building above to cause damage. The use of columns filled with additives such as Calcium Carbide is done to reduce the negative impact of expansive soil behavior. This study aims to determine the effect of carbide columns on expansive soil. Observations were made on swelling and spreading of carbides in the soil. 7 Carbide columns with 5 cm diameter and 20 cm height were installed into the soil with an inter-column spacing of 8.75 cm. Wetting is done through a pipe at the center of the carbide column for 20 days. Observations were conducted on expansive soil without carbide columns and expansive soil with carbide columns. The results showed that the addition of carbide column could reduce the percentage of swelling by 4.42%. Wetting through the center of the carbide column can help spread the carbide into the soil. The use of carbide columns can also decrease the rate of soil expansivity. After the addition of carbide column, the plasticity index value decreased from 71.76% to 4.3% and the shrinkage index decreased from 95.72% to 9.2%.

Contribution of waste water treatment plants to pesticide toxicity in agriculture catchments.

PubMed

Le, Trong Dieu Hien; Scharmüller, Andreas; Kattwinkel, Mira; Kühne, Ralph; Schüürmann, Gerrit; Schäfer, Ralf B

2017-11-01

Pesticide residues are frequently found in water bodies and may threaten freshwater ecosystems and biodiversity. In addition to runoff or leaching from treated agricultural fields, pesticides may enter streams via effluents from wastewater treatment plants (WWTPs). We compared the pesticide toxicity in terms of log maximum Toxic Unit (log mTU) of sampling sites in small agricultural streams of Germany with and without WWTPs in the upstream catchments. We found an approximately half log unit higher pesticide toxicity for sampling sites with WWTPs (p < 0.001). Compared to fungicides and insecticides, herbicides contributed most to the total pesticide toxicity in streams with WWTPs. A few compounds (diuron, terbuthylazin, isoproturon, terbutryn and Metazachlor) dominated the herbicide toxicity. Pesticide toxicity was not correlated with upstream distance to WWTP (Spearman's rank correlation, rho = - 0.11, p > 0.05) suggesting that other context variables are more important to explain WWTP-driven pesticide toxicity. Our results suggest that WWTPs contribute to pesticide toxicity in German streams. Copyright © 2017 Elsevier Inc. All rights reserved.

Liquid chromatographic determination of microcystins in water samples following pre-column excimer fluorescence derivatization with 4-(1-pyrene)butanoic acid hydrazide.

PubMed

Hayama, Tadashi; Katoh, Kenji; Aoki, Takayoshi; Itoyama, Miki; Todoroki, Kenichiro; Yoshida, Hideyuki; Yamaguchi, Masatoshi; Nohta, Hitoshi

2012-11-28

A method to measure the concentrations of microcystins (MCs) in water samples has been developed by incorporating pre-column fluorescence derivatization and liquid chromatography (LC). A solid-phase extraction for pretreatment was used to extract the MCs in water samples. The MCs were derivatized with excimer-forming 4-(1-pyrene)butanoic acid hydrazide (PBH). The MCs could then be detected by fluorescence after separation with a pentafluorophenyl (PFP)-modified superficially porous (core shell) particle LC column. The derivatization reactions of MCs with PBH proceeded easily in the presence of 4,6-dimethoxy-1,3,5-triazin-2-yl-4-methylmorpholinium (DMT-MM) as a condensation reagent, and the resulting derivatives could be easily separated on the PFP column. The derivatives were selectively detected at excimer fluorescence wavelengths (440-540 nm). The instrument detection limit and the instrument quantification limit of the MCs standards were 0.4-1.2 μg L(-1) and 1.4-3.9 μg L(-1), respectively. The method was validated at 0.1 and 1.0 μg L(-1) levels in tap and pond water samples, and the recovery of MCs was between 67 and 101% with a relative standard deviation of 11%. The proposed method can be used to quantify trace amounts of MCs in water samples. Copyright © 2012 Elsevier B.V. All rights reserved.

Theoretical Insight into the Biodegradation of Solitary Oil Microdroplets Moving through a Water Column

PubMed Central

Paraskeva, Christakis A.; Kalogerakis, Nicolas; Doyle, Patrick S.

2018-01-01

In the aftermath of oil spills in the sea, clouds of droplets drift into the seawater column and are carried away by sea currents. The fate of the drifting droplets is determined by natural attenuation processes, mainly dissolution into the seawater and biodegradation by oil-degrading microbial communities. Specifically, microbes have developed three fundamental strategies for accessing and assimilating oily substrates. Depending on their affinity for the oily phase and ability to proliferate in multicellular structures, microbes might either attach to the oil surface and directly uptake compounds from the oily phase, or grow suspended in the aqueous phase consuming solubilized oil, or form three-dimensional biofilms over the oil–water interface. In this work, a compound particle model that accounts for all three microbial strategies is developed for the biodegradation of solitary oil microdroplets moving through a water column. Under a set of educated hypotheses, the hydrodynamics and solute transport problems are amenable to analytical solutions and a closed-form correlation is established for the overall dissolution rate as a function of the Thiele modulus, the Biot number and other key parameters. Moreover, two coupled ordinary differential equations are formulated for the evolution of the particle size and used to investigate the impact of the dissolution and biodegradation processes on the droplet shrinking rate. PMID:29439555

Online Toxicity Monitors (OTM) for Distribution System Water Quality Monitoring

EPA Science Inventory

Drinking water distribution systems in the U.S. are vulnerable to episodic contamination events (both unintentional and intentional). The U.S. Environmental Protection Agency (EPA) is conducting research to investigate the use of broad-spectrum online toxicity monitors (OTMs) in ...

Using ultrahigh-resolution mass spectrometry and toxicity identification techniques to characterize the toxicity of oil sands process-affected water: The case for classical naphthenic acids.

PubMed

Hughes, Sarah A; Mahaffey, Ashley; Shore, Bryon; Baker, Josh; Kilgour, Bruce; Brown, Christine; Peru, Kerry M; Headley, John V; Bailey, Howard C

2017-11-01

Previous assessments of oil sands process-affected water (OSPW) toxicity were hampered by lack of high-resolution analytical analysis, use of nonstandard toxicity methods, and variability between OSPW samples. We integrated ultrahigh-resolution mass spectrometry with a toxicity identification evaluation (TIE) approach to quantitatively identify the primary cause of acute toxicity of OSPW to rainbow trout (Oncorhynchus mykiss). The initial characterization of OSPW toxicity indicated that toxicity was associated with nonpolar organic compounds, and toxicant(s) were further isolated within a range of discrete methanol fractions that were then subjected to Orbitrap mass spectrometry to evaluate the contribution of naphthenic acid fraction compounds to toxicity. The results showed that toxicity was attributable to classical naphthenic acids, with the potency of individual compounds increasing as a function of carbon number. Notably, the mass of classical naphthenic acids present in OSPW was dominated by carbon numbers ≤16; however, toxicity was largely a function of classical naphthenic acids with ≥17 carbons. Additional experiments found that acute toxicity of the organic fraction was similar when tested at conductivities of 400 and 1800 μmhos/cm and that rainbow trout fry were more sensitive to the organic fraction than larval fathead minnows (Pimephales promelas). Collectively, the results will aid in developing treatment goals and targets for removal of OSPW toxicity in water return scenarios both during operations and on mine closure. Environ Toxicol Chem 2017;36:3148-3157. © 2017 SETAC. © 2017 SETAC.

Resuspension of Polychlorinated BiPhenyl-contaminated Field Sediment: Release to the Water Column and Determination of Site-Specific Kdoc

EPA Science Inventory

Sediments from the New Bedford Harbor (NBH) U.S. Environmental Protection Agency (U.S. EPA) Superfund site (Massachusetts, USA), contaminated with polychlorinated biphenyls (PCBs), were resuspended under different water column redox conditions: untreated, oxidative, and reductive...

Acute and subchronic oral toxicity of Coriolus versicolor standardized water extract in Sprague-Dawley rats.

PubMed

Hor, Sook Yee; Ahmad, Mariam; Farsi, Elham; Lim, Chung Pin; Asmawi, Mohd Zaini; Yam, Mun Fei

2011-10-11

Coriolus versicolor, which is known as Yun Zhi, is one of the commonly used Chinese medicinal herbs. Recent studies have demonstrated its antitumor activities on cancer cells which led to its widespread use in cancer patient. However, little toxicological information is available regarding its safety. The present study evaluated the potential toxicity of Coriolus versicolor standardized water extract after acute and subchronic administration in rats. In acute toxicity study, Coriolus versicolor water extract was administered by oral gavage to Sprague-Dawley (SD) rats (6 males, 6 females) at single doses of varying concentrations 1250, 2500 and 5000 mg/kg. In subchronic toxicity study, the extract was administered orally at doses of 1250, 2500 and 5000 mg/kg/day for 28 days to male and female SD rats respectively. General behavior, adverse effects and mortality were determined throughout the experimental period. Haematological and biochemical parameters, relative organ weights and histopathological were evaluated at the end of the experiment. There were no mortality and signs of toxicity in acute and subchronic toxicity studies. In the single dose acute toxicity and repeated dose 28-day subchronic toxicity studies, there were no significant difference in body weight, relative organ weight, haematological parameters, clinical chemistry, gross pathology and histopathology between treatment and control groups. Coriolus versicolor water extract did not cause remarkable adverse effect in SD rats. The oral lethal dose of Coriolus versicolor water extract is more than 5000 mg/kg and no-observed-adverse-effect level (NOAEL) of the extract for both male and female rats is 5000 mg/kg per day for 28 days. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Benthic flux of metals and nutrients into the water column of Lake Coeur d'Alene, Idaho report of an August, 1999, pilot study

USGS Publications Warehouse

Kuwabara, James S.; Berelson, William M.; Balistrieri, Laurie S.; Woods, Paul F.; Topping, Brent R.; Steding, Douglas J.; Krabbenhoft, David P.

2000-01-01

A field study was conducted between August 16-27, 1999, to provide the first direct measurements of the benthic flux of dissolved (0.2-micron filtered) solutes between the bottom sediment and water column at two sites in Lake Coeur d'Alene, Idaho. Trace metals (namely, cadmium, copper, manganese, mercury species, and zinc) and nutrients (namely, ammonia, nitrate plus nitrite, oxygen, orthophosphate and silica) were solutes of primary interest. Benthic flux (sometimes referred to as internal recycling) represents the transport of dissolved chemical species between the water column and the underlying sediment.

A survey of catfish pond water chemistry parameters for copper toxicity modelling

USDA-ARS?s Scientific Manuscript database

Water samples were collected from 20 catfish ponds in 2015 to obtain data useful in predicting copper toxicity and chemical behavior. Ponds were located in major catfish producing areas of west Alabama, east Arkansas, and Mississippi. Pond types included traditional levee ponds, split-ponds, water...

REMEDIATION OF GROUND WATER CONTAMINATED WITH LANDFILL LEACHATE USING PERMEABLE REACTIVE BARRIERS

EPA Science Inventory

The Norman Landfill is the field site for this project. It was reported that ground water toxicity at this site was due to ammonia, and napthalene was the only ASOC present at high concentrations. Thus, batch and column studies will be used to evaluate reactive materials with the...

Whole-cell luminescence biosensor-based lab-on-chip integrated system for water toxicity analysis

NASA Astrophysics Data System (ADS)

Rabner, Arthur; Belkin, Shimshon; Rozen, Rachel; Shacham, Yosi

2006-01-01

A novel water chemical toxin sensor has been successfully developed and evaluated as a working portable laboratory prototype. This sensor relies on a disposable plastic biochip prepared with a 4x4 micro-laboratory (μLab) chambers array of Escherichia coli reporter cells and micro-fluidic channels for liquids translocation. Each bacterial strain has been genetically modified into a bioluminescent reporter that responds to a pre-determined class of chemical agents. When challenged with a water sample containing a toxic chemical, the sensor responds with an increased bioluminescent signal from the biochip that is monitored over time. The signal is received by a motorized photomultiplier-based analyzer and interpreted by signal processing software. We have performed several levels of analysis: (i) the change in the bioluminescent signal from the sensor bacteria serves as a rapid indication for the presence of toxic chemicals in the water sample; (ii) the intensity of the change indicates the toxin concentration level; and (iii) the pattern of the responses for the different members of the bacterial panel on the biochip characterizes the biological origin of the toxin. The analyzer contains housing mechanics, electro-optics for signal acquisition, motorized readout calibration accessories, hydro-pneumatics modules for water sample translocation into biochip micro laboratories, electronics for overall control and communication with the host computer. This prototype has a demonstrated sensitivity for broad classes of water-borne toxic chemicals including naladixic acid (a model genotoxic agent), botulinum and acetylcholine esterase inhibitors. This work has initiated an investigation of a novel handheld field-deployable Water Toxicity Analysis (WTA) device.

Changing patterns in water toxicity associated with current use pesticides in three California agriculture regions.

PubMed

Anderson, Brian S; Phillips, Bryn M; Voorhees, Jennifer P; Deng, Xin; Geraci, Jeff; Worcester, Karen; Tjeerdema, Ron S

2018-03-01

Regulation of agriculture irrigation water discharges in California, USA, is assessed and controlled by its 9 Regional Water Quality Control Boards under the jurisdiction of the California State Water Resources Control Board. Each Regional Water Board has developed programs to control pesticides in runoff as part of the waste discharge requirements implemented through each region's Irrigated Lands Regulatory Program. The present study assessed how pesticide use patterns differ in the Imperial (Imperial County) and the Salinas and Santa Maria (Monterey County) valleys, which host 3 of California's prime agriculture areas. Surface-water toxicity associated with current use pesticides was monitored at several sites in these areas in 2014 and 2015, and results were linked to changes in pesticide use patterns in these areas. Pesticide use patterns appeared to coincide with differences in the way agriculture programs were implemented by the 2 respective Regional Water Quality Control Boards, and these programs differed in the 2 Water Board Regions. Different pesticide use patterns affected the occurrence of pesticides in agriculture runoff, and this influenced toxicity test results. Greater detection frequency and higher concentrations of the organophosphate pesticide chlorpyrifos were detected in agriculture runoff in Imperial County compared to Monterey County, likely due to more rigorous monitoring requirements for growers using this pesticide in Monterey County. Monterey County agriculture runoff contained toxic concentrations of pyrethroid and neonicotinoid pesticides, which impacted amphipods (Hyalella azteca) and midge larvae (Chironomus dilutus) in toxicity tests. Study results illustrate how monitoring strategies need to evolve as regulatory actions affect change in pesticide use and demonstrate the importance of using toxicity test indicator species appropriate for the suite of contaminants in runoff in order to accurately assess environmental risk. Integr

Bacterial toxicity assessment of drinking water treatment residue (DWTR) and lake sediment amended with DWTR.

PubMed

Yuan, Nannan; Wang, Changhui; Pei, Yuansheng

2016-11-01

Drinking water treatment residue (DWTR) seems to be very promising for controlling lake sediment pollution. Logically, acquisition of the potential toxicity of DWTR will be beneficial for its applications. In this study, the toxicity of DWTR and sediments amended with DWTR to Aliivibrio fischeri was evaluated based on the Microtox(®) solid and leachate phase assays, in combination with flow cytometry analyses and the kinetic luminescent bacteria test. The results showed that both solid particles and aqueous/organic extracts of DWTR exhibited no toxicity to the bacterial luminescence and growth. The solid particles of DWTR even promoted bacterial luminescence, possibly because DWTR particles could act as a microbial carrier and provide nutrients for bacteria growth. Bacterial toxicity (either luminescence or growth) was observed from the solid phase and aqueous/organic extracts of sediments with or without DWTR addition. Further analysis showed that the solid phase toxicity was determined to be related mainly to the fixation of bacteria to fine particles and/or organic matter, and all of the observed inhibition resulting from aqueous/organic extracts was identified as non-significant. Moreover, DWTR addition not only had no adverse effect on the aqueous/organic extract toxicity of the sediment but also reduced the solid phase toxicity of the sediment. Overall, in practical application, the solid particles, the water-soluble substances transferred to surface water or the organic substances in DWTR had no toxicity or any delayed effect on bacteria in lakes, and DWTR can therefore be considered as a non-hazardous material. Copyright © 2016 Elsevier Ltd. All rights reserved.

A novel approach for rapidly and cost-effectively assessing toxicity of toxic metals in acidic water using an acidophilic iron-oxidizing biosensor.

PubMed

Yang, Shih-Hung; Cheng, Kuo-Chih; Liao, Vivian Hsiu-Chuan

2017-11-01

Contamination by heavy metals and metalloids is a serious environmental and health concern. Acidic wastewaters are often associated with toxic metals which may enter and spread into agricultural soils. Several biological assays have been developed to detect toxic metals; however, most of them can only detect toxic metals in a neutral pH, not in an acidic environment. In this study, an acidophilic iron-oxidizing bacterium (IOB) Strain Y10 was isolated, characterized, and used to detect toxic metals toxicity in acidic water at pH 2.5. The colorimetric acidophilic IOB biosensor was based on the inhibition of the iron oxidizing ability of Strain Y10, an acidophilic iron-oxidizing bacterium, by metals toxicity. Our results showed that Strain Y10 is acidophilic iron-oxidizing bacterium. Thiobacillus caldus medium (TCM) (pH 2.5) supplied with both S 4 O 6 2- and glucose was the optimum growth medium for Strain Y10. The optimum temperature and pH for the growth of Strain Y10 was 45 °C and pH 2.5, respectively. Our study demonstrates that the color-based acidophilic IOB biosensor can be semi-quantitatively observed by eye or quantitatively measured by spectrometer to detect toxicity from multiple toxic metals at pH 2.5 within 45 min. Our study shows that monitoring toxic metals in acidic water is possible by using the acidophilic IOB biosensor. Our study thus provides a novel approach for rapid and cost-effective detection of toxic metals in acidic conditions that can otherwise compromise current methods of chemical analysis. This method also allows for increased efficiency when screening large numbers of environmental samples. Copyright © 2017 Elsevier Ltd. All rights reserved.

Generalist hydrocarbon-degrading bacterial communities in the oil-polluted water column of the North Sea

PubMed Central

Chronopoulou, Panagiota-Myrsini; Sanni, Gbemisola O; Silas-Olu, Daniel I; van der Meer, Jan Roelof; Timmis, Kenneth N; Brussaard, Corina P D; McGenity, Terry J

2015-01-01

The aim of this work was to determine the effect of light crude oil on bacterial communities during an experimental oil spill in the North Sea and in mesocosms (simulating a heavy, enclosed oil spill), and to isolate and characterize hydrocarbon-degrading bacteria from the water column. No oil-induced changes in bacterial community (3 m below the sea surface) were observed 32 h after the experimental spill at sea. In contrast, there was a decrease in the dominant SAR11 phylotype and an increase in Pseudoalteromonas spp. in the oiled mesocosms (investigated by 16S rRNA gene analysis using denaturing gradient gel electrophoresis), as a consequence of the longer incubation, closer proximity of the samples to oil, and the lack of replenishment with seawater. A total of 216 strains were isolated from hydrocarbon enrichment cultures, predominantly belonging to the genus Pseudoaltero monas; most strains grew on PAHs, branched and straight-chain alkanes, as well as many other carbon sources. No obligate hydrocarbonoclastic bacteria were isolated or detected, highlighting the potential importance of cosmopolitan marine generalists like Pseudoalteromonas spp. in degrading hydrocarbons in the water column beneath an oil slick, and revealing the susceptibility to oil pollution of SAR11, the most abundant bacterial clade in the surface ocean. PMID:25251384

Associations between water physicochemistry and Prymnesium parvum presence, abundance, and toxicity in west Texas reservoirs

USGS Publications Warehouse

VanLandeghem, Matthew M.; Farooqi, Mukhtar; Southard, Greg M.; Patino, Reynaldo

2015-01-01

Toxic blooms of golden alga (Prymnesium parvum) have caused substantial ecological and economic harm in freshwater and marine systems throughout the world. In North America, toxic blooms have impacted freshwater systems including large reservoirs. Management of water chemistry is one proposed option for golden alga control in these systems. The main objective of this study was to assess physicochemical characteristics of water that influence golden alga presence, abundance, and toxicity in the Upper Colorado River basin (UCR) in Texas. The UCR contains reservoirs that have experienced repeated blooms and other reservoirs where golden alga is present but has not been toxic. We quantified golden alga abundance (hemocytometer counts), ichthyotoxicity (bioassay), and water chemistry (surface grab samples) at three impacted reservoirs on the Colorado River; two reference reservoirs on the Concho River; and three sites at the confluence of these rivers. Sampling occurred monthly from January 2010 to July 2011. Impacted sites were characterized by higher specific conductance, calcium and magnesium hardness, and fluoride than reference and confluence sites. At impacted sites, golden alga abundance and toxicity were positively associated with salinity-related variables and blooms peaked at ~10°C and generally did not occur above 20°C. Overall, these findings suggest management of land and water use to reduce hardness or salinity could produce unfavorable conditions for golden alga.

Management of toxic cyanobacteria for drinking water production of Ain Zada Dam.

PubMed

Saoudi, Amel; Brient, Luc; Boucetta, Sabrine; Ouzrout, Rachid; Bormans, Myriam; Bensouilah, Mourad

2017-07-01

Blooms of toxic cyanobacteria in Algerian reservoirs represent a potential health problem, mainly from drinking water that supplies the local population of Ain Zada (Bordj Bou Arreridj). The objective of this study is to monitor, detect, and identify the existence of cyanobacteria and microcystins during blooming times. Samples were taken in 2013 from eight stations. The results show that three potentially toxic cyanobacterial genera with the species Planktothrix agardhii were dominant. Cyanobacterial biomass, phycocyanin (PC) concentrations, and microcystin (MC) concentrations were high in the surface layer and at 14 m depth; these values were also high in the treated water. On 11 May 2013, MC concentrations were 6.3 μg/L in MC-LR equivalent in the drinking water. This study shows for the first time the presence of cyanotoxins in raw and treated waters, highlighting that regular monitoring of cyanobacteria and cyanotoxins must be undertaken to avoid potential health problems.

Toxicity of water from three South Carolina rivers to larval striped bass

USGS Publications Warehouse

Finger, Susan E.; Bulak, James S.

1988-01-01

The toxicity of water from three rivers in the Santee-Cooper drainage of South Carolina was evaluated in a series of on-site studies with larval striped bass Morone saxatilis. Mortality and swimming behavior were assessed daily for larvae exposed to serial dilutions of water collected from the Santee, Congaree, and Wateree rivers. After 96 h, cumulative mortality was 90% in the Wateree River, and a dose–response pattern was evident in serial dilutions of the water. Larvae exposed to water from the Santee and Congaree rivers swam lethargically, but no appreciable mortality was observed. Acutely toxic concentrations of inorganic contaminants were not detected in the rivers; however, pentachloroanisole, a methylated by-product of pentachlorophenol, was twice as high in the Wateree River as it was in the other two rivers. Phenolic compounds may have contributed to larval mortality in the Wateree River and to lethargic activity of larvae in the Santee and Congaree rivers.

Toxicity and chemical analyses of airport runoff waters in Poland.

PubMed

Sulej, Anna Maria; Polkowska, Zaneta; Wolska, Lidia; Cieszynska, Monika; Namieśnik, Jacek

2014-05-01

The aim of this study was to assess the ecotoxicological effects of various compounds in complex airport effluents using a chemical and ecotoxicological integrated strategy. The present work deals with the determination of sum of PCBs, PAHs, pesticides, cations, anions, phenols, anionic, cationic, non-ionic detergents, formaldehyde and metals--as well as TOC and conductivity--in runoff water samples collected from 2009 to 2011 at several locations on two Polish international airports. Two microbiotests (Vibrio fischeri bacteria and the crustacean Thamnocephalus platyurus) have been used to determine the ecotoxicity of airport runoff waters. The levels of many compounds exceeded several or even several tens of times the maximum permissible levels. Analysis of the obtained data shows that samples that displayed maximum toxicity towards the bioindicators Vibrio fischeri were not toxic towards Thamnocephalus platyurus. Levels of toxicity towards T. platyurus are strongly correlated with pollutants that originate from the technological operations related to the maintenance of airport infrastructure. The integrated (chemical-ecotoxicological) approach to environmental contamination assessment in and around airports yields extensive information on the quality of the environment. These methodologies can be then used as tools for tracking the environmental fate of these compounds and for assessing the environmental effect of airports. Subsequently, these data will provide a basis for airport infrastructure management.

Near-Global Survey of Cloud Column Susceptibilities Using ISCCP Data

NASA Technical Reports Server (NTRS)

Han, Qingyuan; Rossow, William B.; Chou, Joyce; Welch, Ronald M.; Hansen, James E. (Technical Monitor)

2000-01-01

A new parameter, cloud column susceptibility, is introduced to study the aerosol indirect effect. There are several advantages of this new parameter in comparison with the traditional cloud susceptibility. First, no assumptions about constant liquid water content and cloud layer thickness are required in calculations so that errors caused by these assumptions can be avoided. Second, no a priori knowledge of liquid water content is necessary in remote sensing, which makes global survey by satellite data possible even though liquid water content may change significantly. Third, this new parameter can deal with variations of cloud geometrical thickness during cloud-aerosol interactions, which are evidenced by Without assuming how cloud droplet size will respond to changes of number concentration, this new parameter describes the aerosol indirect effect more directly. It addresses the question of how cloud albedo changes with increasing column number concentrations of cloud droplets, which is resulted from cloud-aerosol interactions. In this study, two approaches are used to retrieve cloud column susceptibility by satellite data. The results of both approaches show a striking contrast of cloud column susceptibilities between continental and maritime. Between the two approaches, the one that uses no assumption of constant liquid water content leads to smaller, some times even negative, cloud column susceptibilities. This finding suggests that the aerosol indirect effect may be overestimated if the assumption of constant liquid water content is used in model studies.

Comparison of formation and fluid-column logs in a heterogeneous basalt aquifer

USGS Publications Warehouse

Paillet, F.L.; Williams, J.H.; Oki, D.S.; Knutson, K.D.

2002-01-01

Deep observation boreholes in the vicinity of active production wells in Honolulu, Hawaii, exhibit the anomalous condition that fluid-column electrical conductivity logs and apparent profiles of pore-water electrical conductivity derived from induction conductivity logs are nearly identical if a formation factor of 12.5 is assumed. This condition is documented in three boreholes where fluid-column logs clearly indicate the presence of strong borehole flow induced by withdrawal from partially penetrating water-supply wells. This result appears to contradict the basic principles of conductivity-log interpretation. Flow conditions in one of these boreholes was investigated in detail by obtaining flow profiles under two water production conditions using the electromagnetic flowmeter. The flow-log interpretation demonstrates that the fluid-column log resembles the induction log because the amount of inflow to the borehole increases systematically upward through the transition zone between deeper salt water and shallower fresh water. This condition allows the properties of the fluid column to approximate the properties of water entering the borehole as soon as the upflow stream encounters that producing zone. Because this condition occurs in all three boreholes investigated, the similarity of induction and fluid-column logs is probably not a coincidence, and may relate to aquifer response under the influence of pumping from production wells.

Comparison of formation and fluid-column logs in a heterogeneous basalt aquifer.

PubMed

Paillet, F L; Williams, J H; Oki, D S; Knutson, K D

2002-01-01

Deep observation boreholes in the vicinity of active production wells in Honolulu, Hawaii, exhibit the anomalous condition that fluid-column electrical conductivity logs and apparent profiles of pore-water electrical conductivity derived from induction conductivity logs are nearly identical if a formation factor of 12.5 is assumed. This condition is documented in three boreholes where fluid-column logs clearly indicate the presence of strong borehole flow induced by withdrawal from partially penetrating water-supply wells. This result appears to contradict the basic principles of conductivity-log interpretation. Flow conditions in one of these boreholes was investigated in detail by obtaining flow profiles under two water production conditions using the electromagnetic flowmeter. The flow-log interpretation demonstrates that the fluid-column log resembles the induction log because the amount of inflow to the borehole increases systematically upward through the transition zone between deeper salt water and shallower fresh water. This condition allows the properties of the fluid column to approximate the properties of water entering the borehole as soon as the upflow stream encounters that producing zone. Because this condition occurs in all three boreholes investigated, the similarity of induction and fluid-column logs is probably not a coincidence, and may relate to aquifer response under the influence of pumping from production wells.

Toxicity of irradiated advanced heavy water reactor fuels.

PubMed

Priest, N D; Richardson, R B; Edwards, G W R

2013-02-01

The good neutron economy and online refueling capability of the CANDU® heavy water moderated reactor (HWR) enable it to use many different fuels such as low enriched uranium (LEU), plutonium, or thorium, in addition to its traditional natural uranium (NU) fuel. The toxicity and radiological protection methods for these proposed fuels, unlike those for NU, are not well established. This study uses software to compare the fuel composition and toxicity of irradiated NU fuel against those of two irradiated advanced HWR fuel bundles as a function of post-irradiation time. The first bundle investigated is a CANFLEX® low void reactor fuel (LVRF), of which only the dysprosium-poisoned central element, and not the outer 42 LEU elements, is specifically analyzed. The second bundle investigated is a heterogeneous high-burnup (LEU,Th)O(2) fuelled bundle, whose two components (LEU in the outer 35 elements and thorium in the central eight elements) are analyzed separately. The LVRF central element was estimated to have a much lower toxicity than that of NU at all times after shutdown. Both the high burnup LEU and the thorium fuel had similar toxicity to NU at shutdown, but due to the creation of such inhalation hazards as (238)Pu, (240)Pu, (242)Am, (242)Cm, and (244)Cm (in high burnup LEU), and (232)U and (228)Th (in irradiated thorium), the toxicity of these fuels was almost double that of irradiated NU after 2,700 d of cooling. New urine bioassay methods for higher actinoids and the analysis of thorium in fecal samples are recommended to assess the internal dose from these two fuels.

Transport of biocolloids in water saturated columns packed with sand: Effect of grain size and pore water velocity

NASA Astrophysics Data System (ADS)

Syngouna, Vasiliki I.; Chrysikopoulos, Constantinos V.

2012-03-01

The main objective of this study was to evaluate the combined effects of grain size and pore water velocity on the transport in water saturated porous media of three waterborne fecal indicator organisms (Escherichia coli, MS2, and ΦX174) in laboratory-scale columns packed with clean quartz sand. Three different grain sizes and three pore water velocities were examined and the attachment behavior of Escherichia coli, MS2, and ΦX174 onto quartz sand was evaluated. The mass recoveries of the biocolloids examined were shown to be highest for Escherichia coli and lowest for MS2. However, no obvious relationships between mass recoveries and water velocity or grain size could be established from the experimental results. The observed mean dispersivity values for each sand grain size were smaller for bacteria than coliphages, but higher for MS2 than ΦX174. The single collector removal and collision efficiencies were quantified using the classical colloid filtration theory. Furthermore, theoretical collision efficiencies were estimated only for E. coli by the Interaction-Force-Boundary-Layer, and Maxwell approximations. Better agreement between the experimental and Maxwell theoretical collision efficiencies were observed.

Transport of biocolloids in water saturated columns packed with sand: Effect of grain size and pore water velocity

NASA Astrophysics Data System (ADS)

Syngouna, Vasiliki I.; Chrysikopoulos, Constantinos V.

2011-11-01

The main objective of this study was to evaluate the combined effects of grain size and pore water velocity on the transport in water saturated porous media of three waterborne fecal indicator organisms ( Escherichia coli, MS2, and ΦX174) in laboratory-scale columns packed with clean quartz sand. Three different grain sizes and three pore water velocities were examined and the attachment behavior of Escherichia coli, MS2, and ΦX174 onto quartz sand was evaluated. The mass recoveries of the biocolloids examined were shown to be highest for Escherichia coli and lowest for MS2. However, no obvious relationships between mass recoveries and water velocity or grain size could be established from the experimental results. The observed mean dispersivity values for each sand grain size were smaller for bacteria than coliphages, but higher for MS2 than ΦX174. The single collector removal and collision efficiencies were quantified using the classical colloid filtration theory. Furthermore, theoretical collision efficiencies were estimated only for E. coli by the Interaction-Force-Boundary-Layer, and Maxwell approximations. Better agreement between the experimental and Maxwell theoretical collision efficiencies were observed.

Gyrokinetic-water-bag modeling of low-frequency instabilities in a laboratory magnetized plasma column

NASA Astrophysics Data System (ADS)

Gravier, E.; Klein, R.; Morel, P.; Besse, N.; Bertrand, P.

2008-12-01

A new model is presented, named collisional-gyro-water-bag (CGWB), which describes the collisional drift waves and ion-temperature-gradient (ITG) instabilities in a plasma column. This model is based on the kinetic gyro-water-bag approach recently developed [P. Morel et al., Phys. Plasmas 14, 112109 (2007)] to investigate ion-temperature-gradient modes. In CGWB electron-neutral collisions have been introduced and are now taken into account. The model has been validated by comparing CGWB linear analysis with other models previously proposed and experimental results as well. Kinetic effects on collisional drift waves are investigated, resulting in a less effective growth rate, and the transition from collisional drift waves to ITG instability depending on the ion temperature gradient is studied.

Quasi-adiabatic vacuum-based column housing for very high-pressure liquid chromatography.

PubMed

Gritti, Fabrice; Gilar, Martin; Jarrell, Joseph A

2016-07-22

A prototype vacuum-based (10(-6)Torr) column housing was built to thermally isolate the chromatographic column from the external air environment. The heat transfer mechanism is solely controlled by surface radiation, which was minimized by wrapping the column with low-emissivity aluminum tape. The adiabaticity of the column housing was quantitatively assessed from the measurement of the operational pressure and fluid temperature at the outlet of a 2.1mm×100mm column (sub-2 μm particles). The pressure drop along the column was raised up to 1kbar. The enthalpy balance of the eluent (water, acetonitrile, and one water/acetonitrile mixture, 70/30, v/v) showed that less than 1% of the viscous heat generated by friction of the fluid against the packed bed was lost to the external air environment. Such a vacuum-based column oven minimizes the amplitude of the radial temperature gradients across the column diameter and maximizes its resolving power. Copyright © 2016 Elsevier B.V. All rights reserved.

Determining the Influence of Groundwater Composition on the Performance of Arsenic Adsorption Columns Using Rapid Small-Scale Column Tests

NASA Astrophysics Data System (ADS)

Aragon, A. R.; Siegel, M.

2004-12-01

The USEPA has established a more stringent drinking water standard for arsenic, reducing the maximum contaminant level (MCL) from 50 μ g/L to 10 μ g/L. This will affect many small communities in the US that lack the appropriate treatment infrastructure and funding to reduce arsenic to such levels. For such communities, adsorption systems are the preferred technology based on ease of operation and relatively lower costs. The performance of adsorption media for the removal of arsenic from drinking water is dependent on site-specific water quality. At certain concentrations, co-occurring solutes will compete effectively with arsenic for sorption sites, potentially reducing the sorption capacity of the media. Due to the site-specific nature of water quality and variations in media properties, pilot scale studies are typically carried out to ensure that a proposed treatment technique is cost effective before installation of a full-scale system. Sandia National Laboratories is currently developing an approach to utilize rapid small-scale columns in lieu of pilot columns to test innovative technologies that could significantly reduce the cost of treatment in small communities. Rapid small-scale column tests (RSSCTs) were developed to predict full-scale treatment of organic contaminants by adsorption onto granular activated carbon (GAC). This process greatly reduced the time and costs required to verify performance of GAC adsorption columns. In this study, the RSSCT methodology is used to predict the removal of inorganic arsenic using mixed metal oxyhydroxide adsorption media. The media are engineered and synthesized from materials that control arsenic behavior in natural and disturbed systems. We describe the underlying theory and application of RSSCTs for the performance evaluation of novel media in several groundwater compositions. Results of small-scale laboratory columns are being used to predict the performance of pilot-scale systems and ultimately to design full

The concentrations of arsenic and other toxic elements in Bangladesh's drinking water.

PubMed

Frisbie, Seth H; Ortega, Richard; Maynard, Donald M; Sarkar, Bibudhendra

2002-11-01

For drinking water, the people of Bangladesh used to rely on surface water, which was often contaminated with bacteria causing diarrhea, cholera, typhoid, and other life-threatening diseases. To reduce the incidences of these diseases, millions of tubewells were installed in Bangladesh since independence in 1971. This recent transition from surface water to groundwater has significantly reduced deaths from waterborne pathogens; however, new evidence suggests disease and death from arsenic (As) and other toxic elements in groundwater are affecting large areas of Bangladesh. In this evaluation, the areal and vertical distribution of As and 29 other inorganic chemicals in groundwater were determined throughout Bangladesh. This study of 30 analytes per sample and 112 samples suggests that the most significant health risk from drinking Bangladesh's tubewell water is chronic As poisoning. The As concentration ranged from < 0.0007 to 0.64 mg/L, with 48% of samples above the 0.01 mg/L World Health Organization drinking water guideline. Furthermore, this study reveals unsafe levels of manganese (Mn), lead (Pb), nickel (Ni), and chromium (Cr). Our survey also suggests that groundwater with unsafe levels of As, Mn, Pb, Ni, and Cr may extend beyond Bangladesh's border into the four adjacent and densely populated states in India. In addition to the health risks from individual toxins, possible multimetal synergistic and inhibitory effects are discussed. Antimony was detected in 98% of the samples from this study and magnifies the toxic effects of As. In contrast, Se and Zn were below our detection limits in large parts of Bangladesh and prevent the toxic effects of As.

Physical immobility as a sensitive indicator of hydraulic fracturing fluid toxicity towards Daphnia magna.

PubMed

Blewett, Tamzin A; Delompré, Perrine L M; Glover, Chris N; Goss, Greg G

2018-09-01

The process of extracting hydrocarbon resources by hydraulic fracturing is an increasingly utilised technique worldwide, resulting in an effluent called flowback and produced water (FPW). This effluent is a complex mixture of salts, metals and organic compounds, and has been shown to be highly toxic to aquatic biota, an effect attributed mainly to its salt and organic components. However, in the current study we show that the water flea, Daphnia magna, is physically impaired by, and rendered immobile at the surface of, test waters containing FPW. This effect occurs at concentrations significantly lower than the reported median lethal concentration for the same test FPW, and suggests that physical immobility is a more sensitive ecological indicator of adverse environmental effects associated with FPW exposure. We showed that this effect could be mediated by the dual action of waterborne surfactants, which decrease surface tension, and floating hydrocarbons, which adhere to daphnids that break through the water surface and prevent resubmergence. While mortality does not occur in physically impaired daphnids within the prescribed 48h, animals are unable to return to the water column, and thus cannot feed. Stranding at the water surface will also impair the capacity of the animals to shed the carapace, thus impeding reproduction. These results suggest that assessment of acute toxicity of FPW may need to be determined differently from traditional effluent toxicity assessments. Copyright © 2018 Elsevier B.V. All rights reserved.

Testing the toxicity of metals, phenol, effluents, and receiving waters by root elongation in Lactuca sativa L.

PubMed

Lyu, Jie; Park, Jihae; Kumar Pandey, Lalit; Choi, Soyeon; Lee, Hojun; De Saeger, Jonas; Depuydt, Stephen; Han, Taejun

2018-03-01

Phytotoxicity tests using higher plants are among the most simple, sensitive, and cost-effective of the methods available for ecotoxicity testing. In the present study, a hydroponic-based phytotoxicity test using seeds of Lactuca sativa was used to evaluate the water quality of receiving waters and effluents near two industrial sites (Soyo and Daejon) in Korea with respect to the toxicity of 10 metals (As, Cd, Cr, Cu, Fe, Pb, Mn, Hg, Ni, Zn) and phenol, and of the receiving waters and effluents themselves. First, the L. sativa hydroponic bioassay was used to determine whether the receiving water or effluents were toxic; then, the responsible toxicant was identified. The results obtained with the L. sativa bioassay ranked the EC 50 toxicities of the investigated metal ions and phenol as: Cd > Ni > Cu > Zn > Hg > phenol > As > Mn > Cr > Pb > Fe. We found that Zn was the toxicant principally responsible for toxicity in Daejeon effluents. The Daejeon field effluent had a higher Zn concentration than permitted by the effluent discharge criteria of the Ministry of Environment of Korea. Our conclusion on the importance of Zn toxicity was supported by the results of the L. sativa hydroponic assay, which showed that the concentration of Zn required to inhibit root elongation in L. sativa by 50% (EC 50 ) was higher in the Daejeon field effluent than that of pure Zn. More importantly, we proved that the L. sativa hydroponic test method can be applied not only as an alternative tool for determining whether a given waste is acceptable for discharge into public water bodies, but also as an alternative method for measuring the safety of aquatic environments using EC 20 values, with respect to the water pollutants investigated (i.e., Cd, Cr, Cu, Pb, Mn, Hg, Ni, Zn, and phenol). Copyright © 2017. Published by Elsevier Inc.

A Perspective on the Toxicity of Low Concentrations of Petroleum-Derived Polycyclic Aromatic Hydrocarbons to Early Life Stages of Herring and Salmon

PubMed Central

Page, David S.; Chapman, Peter M.; Landrum, Peter F.; Neff, Jerry; Elston, Ralph

2012-01-01

This article presents a critical review of two groups of studies that reported adverse effects to salmon and herring eggs and fry from exposure to 1 μg/L or less of aqueous total polycyclic aromatic hydrocarbons (TPAH), as weathered oil, and a more toxic aqueous extract of “very weathered oil.” Exposure media were prepared by continuously flowing water up through vertical columns containing gravel oiled at different concentrations of Prudhoe Bay crude oil. Uncontrolled variables associated with the use of the oiled gravel columns included time- and treatment-dependent variations in the PAH concentration and composition in the exposure water, unexplored toxicity from other oil constituents/degradation products, potential toxicity from bacterial and fungal activity, oil droplets as a potential contaminant source, inherent differences between control and exposed embryo populations, and water flow rate differences. Based on a review of the evidence from published project reports, peer-reviewed publications, chemistry data in a public database, and unpublished reports and laboratory records, the reviewed studies did not establish consistent dose (concentration) response or causality and thus do not demonstrate that dissolved PAH alone from the weathered oil resulted in the claimed effects on fish embryos at low μg/L TPAH concentrations. Accordingly, these studies should not be relied on for management decision-making, when assessing the risk of very low–level PAH exposures to early life stages of fish. PMID:22754275

A portable cell-based impedance sensor for toxicity testing of drinking water.

PubMed

Curtis, Theresa M; Widder, Mark W; Brennan, Linda M; Schwager, Steven J; van der Schalie, William H; Fey, Julien; Salazar, Noe

2009-08-07

A major limitation to using mammalian cell-based biosensors for field testing of drinking water samples is the difficulty of maintaining cell viability and sterility without an on-site cell culture facility. This paper describes a portable automated bench-top mammalian cell-based toxicity sensor that incorporates enclosed fluidic biochips containing endothelial cells monitored by Electric Cell-substrate Impedance Sensing (ECIS) technology. Long-term maintenance of cells on the biochips is made possible by using a compact, self-contained disposable media delivery system. The toxicity sensor monitors changes in impedance of cell monolayers on the biochips after the introduction of water samples. The fluidic biochip includes an ECIS electronic layer and a polycarbonate channel layer, which together reduce initial impedance disturbances seen in commercially available open well ECIS chips caused by the mechanics of pipetting while maintaining the ability of the cells to respond to toxicants. A curve discrimination program was developed that compares impedance values over time between the control and treatment channels on the fluidic biochip and determines if they are significantly different. Toxicant responses of bovine pulmonary artery endothelial cells grown on fluidic biochips are similar to cells on commercially-available open well chips, and these cells can be maintained in the toxicity sensor device for at least nine days using an automated media delivery system. Longer-term cell storage is possible; bovine lung microvessel endothelial cells survive for up to four months on the fluidic biochips and remain responsive to a model toxicant. This is the first demonstration of a portable bench top system capable of both supporting cell health over extended periods of time and obtaining impedance measurements from endothelial cell monolayers after toxicant exposure.

Stable carbon isotope ratios of archaeal GDGTs in the marine water column and surface sediments

NASA Astrophysics Data System (ADS)

Pearson, A.; Hurley, S.; Close, H. G.; Jasper, C. E.

2016-12-01

Archaeal glycerol dibiphytanyl glycerol tetraether (GDGT) lipids are ubiquitous throughout the marine environment and are preserved in sediments and sedimentary rocks on million-year timescales. Variations in the number of ring-containing GDGT isomers in sediments correlate with differences in overlying sea surface temperatures, a relationship formalized in the TEX86 paleotemperature proxy. Ammonia-oxidizing Thaumarchaeota are believed to be the major sources of these GDGTs, implying that the greatest production and export of GDGTs from the water column should be associated with the maximum expression of ammonia monooxygenase (amoA) genes and maximum number of thaumarchaeal cells, both of which occur in the subsurface NO2- maximum near a depth of ca. 80-250 m. To examine the relationship between production and export of GDGTs from the water column, we measured the concentrations and δ13C values of GDGTs in suspended particulate matter (SPM) of the western South Atlantic Ocean and compared them to values from pure thaumarchaeal cultures and from available sediment core-tops from other locations. Thaumarchaeota are believed to fix the majority of their carbon directly from dissolved inorganic carbon (DIC). However, both the SPM and core-top δ13C values in some cases are moderately more 13C-depleted than would be predicted based on the 13C content of local DIC and the previously-published biosynthetic isotope fractionation (ɛ). This indicates that the average metabolism of the planktonic archaeal community either is mixotrophic (≥ 25% organic carbon assimilation) or that the published ɛ value for the model organism Nitrosopumilus maritimus may not be representative of the total autotrophic community. In addition to this offset, δ13C values of GDGTs in SPM inversely mirror DIC profiles, with lowest values in the nitrite maximum and higher values in the deeper water column, similar to the overall trends for bulk SPM. Finally, while individual GDGTs in SPM samples

Toxic effects of juvenile sablefish, Anoplopoma fimbria by ammonia exposure at different water temperature.

PubMed

Kim, Jun-Hwan; Park, Hee-Ju; Hwang, In-Ki; Han, Jae-Min; Kim, Do-Hyung; Oh, Chul Woong; Lee, Jung-Sick; Kang, Ju-Chan

2017-09-01

Juvenile sablefish, Anoplopoma fimbria (mean length 17.1±2.4cm, and mean weight 75.6±5.7g) were used to evaluate toxic effects on antioxidant systems, immune responses, and stress indicators by ammonia exposure (0, 0.25, 0.75, and 1.25mg/L) at different water temperature (12 and 17°C) in 1 and 2 months. In antioxidant responses, superoxide dismutase (SOD) and catalase (CAT) were significantly increased by ammonia exposure, whereas glutathione (GSH) was decreased. In immune responses, lysozyme and phagocytosis activity were significantly increased by ammonia exposure. In stress indicators, plasma glucose, heat shock protein 70 (HSP 70), and cortisol were significantly increased. At high water temperature (17°C), alterations by ammonia exposure were more distinctly. The results of this study indicated that ammonia exposure can induce toxic effects in the sablefish, and high water temperature can affect the ammonia exposure toxicity. Copyright © 2017 Elsevier B.V. All rights reserved.

Trends and variability in column-integrated atmospheric water vapor

NASA Astrophysics Data System (ADS)

Trenberth, Kevin E.; Fasullo, John; Smith, Lesley

2005-06-01

An analysis and evaluation has been performed of global datasets on column-integrated water vapor (precipitable water). For years before 1996, the Ross and Elliott radiosonde dataset is used for validation of European Centre for Medium-range Weather Forecasts (ECMWF) reanalyses ERA-40. Only the special sensor microwave imager (SSM/I) dataset from remote sensing systems (RSS) has credible means, variability and trends for the oceans, but it is available only for the post-1988 period. Major problems are found in the means, variability and trends from 1988 to 2001 for both reanalyses from National Centers for Environmental Prediction (NCEP) and the ERA-40 reanalysis over the oceans, and for the NASA water vapor project (NVAP) dataset more generally. NCEP and ERA-40 values are reasonable over land where constrained by radiosondes. Accordingly, users of these data should take great care in accepting results as real. The problems highlight the need for reprocessing of data, as has been done by RSS, and reanalyses that adequately take account of the changing observing system. Precipitable water variability for 1988 2001 is dominated by the evolution of ENSO and especially the structures that occurred during and following the 1997 98 El Niño event. The evidence from SSM/I for the global ocean suggests that recent trends in precipitable water are generally positive and, for 1988 through 2003, average 0.40±0.09 mm per decade or 1.3±0.3% per decade for the ocean as a whole, where the error bars are 95% confidence intervals. Over the oceans, the precipitable water variability relates very strongly to changes in SSTs, both in terms of spatial structure of trends and temporal variability (with a regression coefficient for 30°N 30°S of 7.8% K-1) and is consistent with the assumption of fairly constant relative humidity. In the tropics, the trends are also influenced by changes in rainfall which, in turn, are closely associated with the mean flow and convergence of moisture

Water or sediment? Partitioning the role of water column and sediment chemistry as drivers of macroinvertebrate communities in an austral South African stream.

PubMed

Dalu, Tatenda; Wasserman, Ryan J; Tonkin, Jonathan D; Mwedzi, Tongayi; Magoro, Mandla L; Weyl, Olaf L F

2017-12-31

Water pollution is a critical management issue, with many rivers and streams draining urban areas being polluted by the disposal of untreated solid waste and wastewater discharge, storm water and agricultural runoff. This has implications for biodiversity, and many rivers in the developing world are now considered compromised. We investigated benthic macroinvertebrate community structure and composition in relation to physico-chemical conditions of the water column and sediments. The study was conducted in an Austral catchment subject to both urban and agricultural pollutants in two different seasons. We assessed whether sediment characteristics were more important drivers of macroinvertebrate community composition than water column characteristics. We expected clear differences in macroinvertebrate community composition and in the associated community metrics due to distinct flow conditions between the two seasons. A combination of multivariate analyses (canonical correspondence analysis (CCA)) and biological indicator analysis were used to examine these patterns. Chironomidae was the most abundant family (>60%) in the upper mainstem river and stream sites. Stream sites were positively associated with CCA axis 2, being characterised by high turbidity and lower pH, salinity, phosphate concentration, channel width and canopy cover. Canopy cover, channel width, substrate embeddedness, phosphate concentration, pH, salinity and turbidity all had a significant effect on macroinvertebrate community composition. Using CCA variation partitioning, water quality was, however, a better predictor of benthic macroinvertebrate composition than sediment chemical conditions. Furthermore, our results suggest that seasonality had little effect on structuring benthic macroinvertebrate communities in this south-eastern zone of South Africa, despite clear changes in sediment chemistry. This likely reflects the relative lack of major variability in water chemistry compared to sediment

Testing the Role of Microbial Ecology, Redox-Mediated Deep Water Production and Hypersalinity on TEX86: Lipids and 16s Sequences from Archaea and Bacteria in the Water Column and Sediments of Orca Basin

NASA Astrophysics Data System (ADS)

Warren, C.; Romero, I.; Ellis, G.; Goddard, E.; Krishnan, S.; Nigro, L. M.; Super, J. R.; Zhang, Y.; Zhuang, G.; Hollander, D. J.; Pagani, M.

2014-12-01

Mesophilic marine archaea and bacteria are known to substantially contribute to the oceanic microbial biomass and play critical roles in global carbon, nitrogen and nutrient cycles. The Orca Basin, a 2400 meter deep bathymetric depression on the continental slope of the north-central Gulf of Mexico, is an ideal environment to examine how redox-dependent biochemical processes control the input and cycling of bacterial and archaea-derived lipid compounds from formation in near-surface water, through secondary recycling processes operating at the redox-transition in the water column, to sedimentary diagenetic processes operating in oxic to anoxic zones within the basin. The lowermost 180 meters of the Orca Basin is characterized by an anoxic, hypersaline brine that is separated from the overlying oxic seawater by a well-defined redox sequence associated with a systematic increasing in salinity from 35 - 250‰. While surface water conditions are viewed as normal marine with a seasonally productive water column, the sub-oxic to anoxic transition zones within the deep-water column and the sediment spans over 200 m allowing the unique opportunity for discrete sampling of resident organisms and lipids. Here we present 16s rRNA sequence data of Bacteria and Archaea collected parallel to GDGT lipid profiles and in situ environmental measurements from the sediment and overlying water column in the intermediate zone of the basin, where movements of chemical transition zones are preserved. We evaluated GDGTs and corresponding taxa across the surface water, chlorophyll maximum, thermocline, and the deep redox boundary, including oxygenation, denitrification, manganese, iron and sulfate reduction zones, to determine if GDGTs are being produced under these conditions and how surface-derived GDGT lipids and the TEX86 signal may be altered. The results have implications for the application of the TEX86 paleotemperature proxy.

Properties of Two-Variety Natural Luffa Sponge Columns as Potential Mattress Filling Materials

PubMed Central

Chen, Yuxia; Zhang, Kaiting; Yuan, Fangcheng; Zhang, Tingting; Weng, Beibei; Wu, Shanshan; Huang, Aiyue; Su, Na; Guo, Yong

2018-01-01

Luffa sponge (LS) is a resourceful material with fibro-vascular reticulated structure and extremely high porosity, which make it a potential candidate for manufacturing light mattress. In this study, two types of LS columns, namely high-density (HD) and low-density (LD) columns, were investigated as materials for filling the mattress. The results showed that the compressive strength of HD LS columns was significantly greater than that of LD LS columns. However, the densification strains of the two types of LS column were both in the range of 0.6 to 0.7. Besides, HD LS columns separately pressed to the smooth plateau region and the initial densification region exhibited a partial recovery of instant height when they were unloaded, and then both of them showed no more than 4.2% of height recovery after being allowed to rest at a constant temperature and humidity for 24 h. In contrast, when LD LS columns were compressed to the smooth plateau region, the height recovery was less than 1.62% compared to when they were pressed to the initial densification region, and that was more than 15.62%. Similar to other plant fibers used as mattress fillers, the two types of LS columns also showed good water absorption capacity—both of them could absorb water from as much as 2.07 to 3.45 times their own weight. At the same time, the two types of LS columns also showed good water desorption. The water desorption ratio of HD and LD LS columns separately reached 76.86 and 91.44%, respectively, after being let rest at a constant temperature and humidity for 13 h. PMID:29614744

Fate and Transport of CL-20 and RDX in Unsaturated Laboratory Columns

NASA Astrophysics Data System (ADS)

Lemond, L. A.; Gamerdinger, A. P.; Szecsody, J. E.

2005-05-01

This research examines the fate and transport of two explosive compounds, Hexanitrohexaazaisowurtzitane (CL-20) and Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in unsaturated laboratory columns. The transport and fate of these compounds were studied under saturated and unsaturated conditions in three natural soils: coarse sand, sandy loam, and a silt loam. Unsaturated column experiments were conducted using an ultra-centrifugation method. Sorption and degradation parameters were determined by moment analysis and hydrodynamic parameters were assessed with a two-region flow model. Differences in these parameters were evaluated as a function of water content. The fate and transport of CL-20 is highly dependent on 1) the soil type and 2) the compound's residence time in the soil and 3) water content of the media. Sorption of CL-20 was rate-limited. CL-20 degradation in saturated columns produced a half-life of as much as 22hr, but in unsaturated columns the degradation rate increased considerably, producing a half life of as little as 2hr. The fate and transport of RDX are also affected by the soil type, but sorption appeared to be instantaneous. Degradation of RDX was negligible. Our results suggest that at very low water content immobile water regions may become (at least in effect) isolated water regions and significantly alter the retardation of the tracer. In the sandy loam, there was as much as a 20-fold over-prediction of the retardation factor in the unsaturated saturated columns when predicted by Kd values derived from saturated columns. In the coarse sand, Kd values derived from saturated columns over-predicted retardation in the unsaturated columns by as much as 30%. In the silt loam, retardation factors were over-predicted by as much as 80%. At very low water contents, predictions of tracer behavior become very difficult because of changes in the flow regime that cannot be directly accounted for.

Surfactant enhanced remediation of soil columns contaminated by residual tetrachloroethylene

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pennell, K.D.; Jin, M.; Abriola, L.M.

1994-01-01

The ability of aqueous surfactant solutions to recover tetrachloroethylene (PCE) entrapped in Ottawa sand was evaluated in four column experiments. Residual PCE was emplaced by injecting (14)C-labeled PCE into water-saturated soil columns and displacing the free product with water. Miscible displacement experiments were conducted before and after PCE entrapment to determine the influence or residual PCE on column dispersivities. The first two column studies involved the injection of a 4% solution of polyoxyethylene (POE) (20) sorbitan monooleate, resulting in the removal of 90% and 97% of the residual PCE from 20-30- and 40-120-mesh Ottawa sand, respectively. Although micellar solubilization ofmore » PCE was the primary mode of recovery in these experiments, this process was shown to be rate-limited.« less

Modeling Cooling Rates of Martian Flood Basalt Columns

NASA Astrophysics Data System (ADS)

Weiss, D. K.; Jackson, B.; Milazzo, M. P.; Barnes, J. W.

2011-12-01

Columnar jointing in large basalt flows have been extensively studied and can provide important clues about the emplacement conditions and cooling history of a basalt flow. The recent discovery of basalt columns on Mars in crater walls near Marte Vallis provides an opportunity to infer conditions on early Mars when the Martian basalt flows were laid down. Comparison of the Martian columns to Earth analogs allows us to gain further insight into the early Martian climate, and among the best terrestrial analogs are the basalt columns in the Columbia River Basalt Group (CRBG) in eastern Washington. The CRBG is one of the youngest (< 17 Myrs old) and most extensively studied basalt provinces in the world, extending over 163,700 square km with total thickness exceeding 1 km in some places. The morphologies and textures of CRBG basalt columns suggest that in many places flows ~100 m thick cooled at uniform rates, even deep in the flow interior. Such cooling seems to require the presence of water in the column joints since the flow interiors should have cooled much more slowly than the flow margins if conductive cooling dominated. Secondary features, such pillow basalts, likewise suggest the basalt flows were in direct contact with standing water in many places. At the resolution provided by the orbiting HiRISE camera (0.9 m), the Martian basalt columns resemble the CRBG columns in many respects, and so, subject to important caveats, inferences linking the morphologies of the CRBG columns to their thermal histories can be extended in some respects to the Martian columns. In this presentation, we will describe our analysis of the HiRISE images of the Martian columns and what can be reasonably inferred about their thermal histories and the conditions under which they were emplaced. We will also report on a field expedition to the CRBG in eastern Washington State. During that expedition, we surveyed basalt column outcrops on the ground and from the air using Unmanned Aerial

Retrieval of water vapor column abundance and aerosol properties from ChemCam passive sky spectroscopy

DOE PAGES

McConnochie, Timothy H.; Smith, Michael D.; Wolff, Michael J.; ...

2017-11-03

In this work, we derive water vapor column abundances and aerosol properties from Mars Science Laboratory (MSL) ChemCam passive mode observations of scattered sky light. This paper covers the methodology and initial results for water vapor and also provides preliminary results for aerosols. The data set presented here includes the results of 113 observations spanning from Mars Year 31 L s = 291° (March 30, 2013) to Mars Year 33 L s= 127° (March 24, 2016). Each ChemCam passive sky observation acquires spectra at two different elevation angles. We fit these spectra with a discrete-ordinates multiple scattering radiative transfer model,more » using the correlated-k approximation for gas absorption bands. The retrieval proceeds by first fitting the continuum of the ratio of the two elevation angles to solve for aerosol properties, and then fitting the continuum-removed ratio to solve for gas abundances. The final step of the retrieval makes use of the observed CO 2 absorptions and the known CO 2 abundance to correct the retrieved water vapor abundance for the effects of the vertical distribution of scattering aerosols and to derive an aerosol scale height parameter. Our water vapor results give water vapor column abundance with a precision of ±0.6 precipitable microns and systematic errors no larger than ±0.3 precipitable microns, assuming uniform vertical mixing. The ChemCam-retrieved water abundances show, with only a few exceptions, the same seasonal behavior and the same timing of seasonal minima and maxima as the TES, CRISM, and REMS-H data sets that we compare them to. However ChemCam-retrieved water abundances are generally lower than zonal and regional scale from-orbit water vapor data, while at the same time being significantly larger than pre-dawn REMS-H abundances. Pending further analysis of REMS-H volume mixing ratio uncertainties, the differences between ChemCam and REMS-H pre-dawn mixing ratios appear to be much too large to be explained by large

Retrieval of water vapor column abundance and aerosol properties from ChemCam passive sky spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

McConnochie, Timothy H.; Smith, Michael D.; Wolff, Michael J.

In this work, we derive water vapor column abundances and aerosol properties from Mars Science Laboratory (MSL) ChemCam passive mode observations of scattered sky light. This paper covers the methodology and initial results for water vapor and also provides preliminary results for aerosols. The data set presented here includes the results of 113 observations spanning from Mars Year 31 L s = 291° (March 30, 2013) to Mars Year 33 L s= 127° (March 24, 2016). Each ChemCam passive sky observation acquires spectra at two different elevation angles. We fit these spectra with a discrete-ordinates multiple scattering radiative transfer model,more » using the correlated-k approximation for gas absorption bands. The retrieval proceeds by first fitting the continuum of the ratio of the two elevation angles to solve for aerosol properties, and then fitting the continuum-removed ratio to solve for gas abundances. The final step of the retrieval makes use of the observed CO 2 absorptions and the known CO 2 abundance to correct the retrieved water vapor abundance for the effects of the vertical distribution of scattering aerosols and to derive an aerosol scale height parameter. Our water vapor results give water vapor column abundance with a precision of ±0.6 precipitable microns and systematic errors no larger than ±0.3 precipitable microns, assuming uniform vertical mixing. The ChemCam-retrieved water abundances show, with only a few exceptions, the same seasonal behavior and the same timing of seasonal minima and maxima as the TES, CRISM, and REMS-H data sets that we compare them to. However ChemCam-retrieved water abundances are generally lower than zonal and regional scale from-orbit water vapor data, while at the same time being significantly larger than pre-dawn REMS-H abundances. Pending further analysis of REMS-H volume mixing ratio uncertainties, the differences between ChemCam and REMS-H pre-dawn mixing ratios appear to be much too large to be explained by large

Drivers of Water Column Calcium Carbonate Fluxes and Dissolution in the Gulf of Maine: Impacts on the Carbon Cycle

NASA Astrophysics Data System (ADS)

Pilskaln, C. H.; Wang, A. Z.; Lawson, G. L.; Hayashi, K.; Salisbury, J.

2016-02-01

Recent studies indicate that the U.S. Northeast coastal region, particularly the Gulf of Maine (GoME), may be more susceptible to ocean acidification (OA) than previously thought due to the low buffer capacity, low pH, and low calcium carbonate saturation measured in the region. In particular, sub-surface waters of the GoME already experience under-saturation with respect to aragonite in spring and summer and recent data suggest that water-column aragonite dissolution may occur throughout the year, even when aragonite is slightly over-saturated. This dissolution process appears associated with organic carbon remineralization in the extensive benthic nepheloid layers and may thus represent a major control over the calcium carbonate (CaCO3) budget of deep, near-bottom waters of the GoME. These findings are surprising for shallow, non-upwelling shelf systems and have important implications for the CaCO3 cycle, shell-building organisms, and the GoME planktonic ecosystem. Additionally, freshening of the GoME over the past several decades due to an increase in low-salinity water input originating in the Labrador Sea may further decrease seawater pH and aragonite saturation in the gulf. We present a variety of biogeochemical data that suggest linkages between potential water column CaCO3 dissolution and their impacts on the GoME carbon cycle.

Occurrence of microbial indicators and Clostridium perfringens in wastewater, water column samples, sediments, drinking water, and Weddell seal feces collected at McMurdo Station, Antarctica

USGS Publications Warehouse

Lisle, J.T.; Smith, J.J.; Edwards, D.D.; McFeters, G.A.

2004-01-01

McMurdo Station, Antarctica, has discharged untreated sewage into McMurdo Sound for decades. Previous studies delineated the impacted area, which included the drinking water intake, by using total coliform and Clostridium perfringens concentrations. The estimation of risk to humans in contact with the impacted and potable waters may be greater than presumed, as these microbial indicators may not be the most appropriate for this environment. To address these concerns, concentrations of these and additional indicators (fecal coliforms, Escherichia coli, enterococci, coliphage, and enteroviruses) in the untreated wastewater, water column, and sediments of the impacted area and drinking water treatment facility and distribution system at McMurdo Station were determined. Fecal samples from Weddell seals in this area were also collected and analyzed for indicators. All drinking water samples were negative for indicators except for a single total coliform-positive sample. Total coliforms were present in water column samples at higher concentrations than other indicators. Fecal coliform and enterococcus concentrations were similar to each other and greater than those of other indicators in sediment samples closer to the discharge site. C. perfringens concentrations were higher in sediments at greater distances from the discharge site. Seal fecal samples contained concentrations of fecal coliforms, E. coli, enterococci, and C. perfringens similar to those found in untreated sewage. All samples were negative for enteroviruses. A wastewater treatment facility at McMurdo Station has started operation, and these data provide a baseline data set for monitoring the recovery of the impacted area. The contribution of seal feces to indicator concentrations in this area should be considered.

HPLC column-switching technique for sample preparation and fluorescence determination of propranolol in urine using fused-core columns in both dimensions.

PubMed

Satínský, Dalibor; Havlíková, Lucie; Solich, Petr

2013-08-01

A new and fast high-performance liquid chromatography (HPLC) column-switching method using fused-core columns in both dimensions for sample preconcentration and determination of propranolol in human urine has been developed. On-line sample pretreatment and propranolol preconcentration were performed on an Ascentis Express RP-C-18 guard column (5 × 4.6 mm), particle size, 2.7 μm, with mobile phase acetonitrile/water (5:95, v/v) at a flow rate of 2.0 mL min(-1) and at a temperature of 50 °C. Valve switch from pretreatment column to analytical column was set at 4.0 min in a back-flush mode. Separation of propranolol from other endogenous urine compounds was achieved on the fused-core column Ascentis Express RP-Amide (100 × 4.6 mm), particle size, 2.7 μm, with mobile phase acetonitrile/water solution of 0.5% triethylamine, pH adjusted to 4.5 by means of glacial acetic acid (25:75, v/v), at a flow rate of 1.0 mL min(-1) and at a temperature of 50 °C. Fluorescence excitation/emission detection wavelengths were set at 229/338 nm. A volume of 1,500 μL of filtered urine sample solution was injected directly into the column-switching HPLC system. The total analysis time including on-line sample pretreatment was less than 8 min. The experimentally determined limit of detection of the method was found to be 0.015 ng mL(-1).

Application of passive sampling for measuring dissolved concentrations of organic contaminants in the water column at three marine superfund sites

EPA Science Inventory

At contaminated sediment sites, including U.S. EPA Superfund sites, it is critical to measure water column concentrations of freely dissolved contaminants to understand the complete exposure of aquatic organisms to hydrophobic organic contaminants (HOCs). However, historically a...

Performance of a biological deoxygenation process for ships' ballast water treatment under very cold water conditions.

PubMed

de Lafontaine, Yves; Despatie, Simon-Pierre

2014-02-15

Water deoxygenation is listed among the promising on-board treatment technologies to treat ships' ballast waters to reduce the risk of species transfer. We assessed the performance of a yeast-based bioreactive deoxygenation process in very cold water (<2°C) and determined the potential toxicity of the residual treated waters. Experiments using two treatment levels (0.5% and 1% v/v) were conducted in large-volume (4.5m(3)) tanks over 19 days at mean temperature of 1.5°C. Time to hypoxia varied between 10.3 and 16 days, being slightly higher than the predicted time of 9.8 days from previous empirical relationships. Water deoxygenation was achieved when yeast density exceeded 5×10(5) viable cellsmL(-1) and variation in time to hypoxia was mainly explained by difference in yeast growth. There was no oxycline and no significant difference in yeast density over the 2-m deep water column. Results from six bioassays indicated weak toxic response of treated waters at the 1.0% level, but no potential toxic response at the 0.5% treatment level. Results confirmed that the potential application of a yeast-based deoxygenation process for treating ships' ballast waters extended over the range of water temperature typically encountered during most shipping operational conditions. Time to reach full deoxygenation may however be limiting for universal application of this treatment which should be preferably used for ships making longer voyages in cold environments. There was no evidence that biological deoxygenation at low temperature did increase toxicity risk of treated waters to impede their disposal at the time of discharge. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

Aluminum-based water treatment residual use in a constructed wetland for capturing urban runoff phosphorus: Column study

USDA-ARS?s Scientific Manuscript database

Aluminum-based water treatment residuals (Al-WTR) have a strong affinity to sorb phosphorus. In a proof-of-concept greenhouse column study, Al-WTR was surface-applied at 0, 62, 124, and 248 Mg/ha to 15 cm of soil on top of 46 cm of sand; Al-WTR rates were estimated to capture 0, 10, 20, and 40 year...

Delineation of estuarine fronts in the German Bight using airborne laser-induced water Raman backscatter and fluorescence of water column constituents

NASA Technical Reports Server (NTRS)

Hoge, F. E.; Swift, R. N.

1982-01-01

The acquisition and application of airborne laser induced emission spectra from German Bight water during the 1979 MARSEN experiment is detailed for the synoptic location of estuarine fronts. The NASA Airborne Oceanographic Lidar (AOL) was operated in the fluorosensing mode. A nitrogen laser transmitter at 337.1 nm was used to stimulate the water column to obtain Gelbstoff or organic material fluorescence spectra together with water Raman backscatter. Maps showing the location and relative strength of estuarine fronts are presented. The distribution of the fronts indicates that mixing within the German Bight takes place across a relatively large area. Reasonable agreement between the patterns observed by the AOL and published results are obtained. The limitations and constraints of this technique are indicated and improvements to the AOL fluorosensor are discussed with respect to future ocean mapping applications.

Impact of water chemistry on the particle-specific toxicity of copper nanoparticles to Daphnia magna.

PubMed

Xiao, Yinlong; Peijnenburg, Willie J G M; Chen, Guangchao; Vijver, Martina G

2018-01-01

Toxicity of metallic nanoparticle suspensions (NP (total) ) is generally assumed to result from the combined effect of the particles present in suspensions (NP (particle) ) and their released ions (NP (ion) ). Evaluation and consideration of how water chemistry affects the particle-specific toxicity of NP (total) are critical for environmental risk assessment of nanoparticles. In this study, it was found that the toxicity of Cu NP (particle) to Daphnia magna, in line with the trends in toxicity for Cu NP (ion) , decreased with increasing pH and with increasing concentrations of divalent cations and dissolved organic carbon (DOC). Without the addition of DOC, the toxicity of Cu NP (total) to D. magna at the LC50 was driven mainly by Cu NP (ion) (accounting for ≥53% of the observed toxicity). However, toxicity of Cu NP (total) in the presence of DOC at a concentration ranging from 5 to 50mg C/L largely resulted from the NP (particle) (57%-85%), which could be attributable to the large reduction of the concentration of Cu NP (ion) and the enhancement of the stability of Cu NP (particle) when DOC was added. Our results indicate that water chemistry needs to be explicitly taken into consideration when evaluating the role of NP (particle) and NP (ion) in the observed toxicity of NP (total) . Copyright © 2017 Elsevier B.V. All rights reserved.

Rare earth elements in the water column of Lake Vanda, McMurdo Dry Valleys, Antarctica

NASA Astrophysics Data System (ADS)

De Carlo, Eric Heinen; Green, William J.

2002-04-01

We present data on the composition of water from Lake Vanda, Antarctica. Vanda and other lakes in the McMurdo Dry Valleys of Antarctica are characterized by closed basins, permanent ice covers, and deep saline waters. The meromictic lakes provide model systems for the study of trace metal cycling owing to their pristine nature and the relative simplicity of their biogeochemical systems. Lake Vanda, in the Wright Valley, is supplied by a single input, the Onyx River, and has no output. Water input to the lake is balanced by sublimation of the nearly permanent ice cap that is broken only near the shoreline during the austral summer. The water column is characterized by an inverse thermal stratification of anoxic warm hypersaline water underlying cold oxic freshwater. Water collected under trace-element clean conditions was analyzed for its dissolved and total rare earth element (REE) concentrations by inductively coupled plasma mass spectrometry. Depth profiles are characterized by low dissolved REE concentrations (La, Ce, <15 pM) in surface waters that increase slightly (La, 70 pM; Ce, 20 pM) with increasing depth to ∼55 m, the limit of the fresh oxic waters. Below this depth, a sharp increase in the concentrations of strictly trivalent REE (e.g., La, 5 nM) is observed, and a submaximum in redox sensitive Ce (2.6 nM) is found at 60- to 62-m depth. At a slightly deeper depth, a sharper Ce maximum is observed with concentrations exceeding 11 nM at a 67-m depth, immediately above the anoxic zone. The aquatic concentrations of REE reported here are ∼50-fold higher than previously reported for marine oxic/anoxic boundaries and are, to our knowledge, the highest ever observed at natural oxic/anoxic interfaces. REE maxima occur within stable and warm saline waters. All REE concentrations decrease sharply in the sulfidic bottom waters. The redox-cline in Lake Vanda is dominated by diffusional processes and vertical transport of dissolved species driven by concentration

Pesticide concentrations in water and sediment and associated invertebrate toxicity in Del Puerto and Orestimba Creeks, California, 2007-2008.

PubMed

Ensminger, Michael; Bergin, Rick; Spurlock, Frank; Goh, Kean S

2011-04-01

The California's San Joaquin River and its tributaries including Orestimba (ORC) and Del Puerto (DPC) Creeks are listed on the 2006 US EPA Clean Water Act §303(d) list for pesticide impairment. From December 2007 through June 2008, water and sediment samples were collected from both creeks in Stanislaus County to determine concentrations of organophosphorus (OP) and pyrethroid insecticides and to identify toxicity to Ceriodaphnia dubia and Hyalella azteca. OPs were detected in almost half (10 of 21) of the water samples, at concentrations from 0.005 to 0.912 μg L(-1). Diazinon was the most frequently detected OP, followed by chlorpyrifos and dimethoate. Two water samples were toxic to C. dubia; based on median lethal concentrations (LC50), chlorpyrifos was likely the cause of this toxicity. Pyrethroids were detected more frequently in sediment samples (18 detections) than in water samples (three detections). Pyrethroid concentrations in water samples ranged from 0.005 to 0.021 μg L(-1). These concentrations were well below reported C. dubia LC50s, and toxicity was not observed in laboratory bioassays. Cyfluthrin, bifenthrin, esfenvalerate, and λ-cyhalothrin were detected in sediment samples at concentrations ranging from 1.0 to 74.4 ng g(-1), dry weight. At DPC, all but one sediment sample caused 100% toxicity to H. azteca. Based on estimated toxicity units (TUs), bifenthrin was likely responsible for this toxicity and λ-cyhalothrin also contributed. At ORC, survival of H. azteca was significantly reduced in four of the 11 sediment samples. However, pyrethroids were detected in only two of these samples. Based on TUs, bifenthrin and λ-cyhalothrin likely contributed to the toxicity.

The influence of particles on bioavailability and toxicity of pesticides in surface water.

PubMed

Knauer, Katja; Homazava, Nadzeya; Junghans, Marion; Werner, Inge

2017-07-01

Environmental risk assessment is an essential part of the approval process for pesticides. Exposure concentrations are compared with ecotoxicological data obtained from standardized laboratory studies and, if available, from field studies to determine the risk of a substance or formulation for aquatic communities. Predicted concentrations in surface waters are derived using, for example, the European FOrum for the Co-ordination of pesticide fate models and their USe (FOCUS) or the German Exposit models, which distinguish between exposure to dissolved and particle-associated pesticide concentrations, because the dissolved concentration is thought to be the best predictor of bioavailability and toxicity. Water and particle-associated concentrations are estimated based on the organic carbon-water partitioning coefficient (K OC ). This review summarizes published information on the influence of natural suspended solids on bioavailability and toxicity of pesticides to aquatic organisms (algae, invertebrates and fish), and the value of log K OC and log K OW (octanol-water coefficient) as sole predictors of the bioavailable fraction is discussed. The information showed that: 1) the quality and origin of suspended solids played an important role in influencing pesticide bioavailability and toxicity; 2) a decrease in toxicity due to the presence of suspended solids was shown only for pyrethroid insecticides with log K OW greater than 5, but the extent of this reduction depended on particle concentration and size, and potentially also on the ecotoxicological endpoint; 3) for pesticides with a log K OW less than 3 (e.g., triazines, carbamates, and organophosphates), the impact of particles on bioavailability and toxicity is small and species dependent; and 4) pesticide bioavailability is greatly influenced by the test species and their physiology (e.g., feeding behavior or digestion). We conclude that exposure of aquatic organisms to pesticides and environmental risk of many

Effects of Irradiance on Benthic and Water Column Processes in a Gulf of Mexico Estuary: Pensacola Bay, Florida, USA

EPA Science Inventory

We examined the effect of light on water column and benthic fluxes in the Pensacola Bay estuary, a river-dominated system in the northeastern Gulf of Mexico. Measurements were made during summer 2003 and 2004 on 16 dates at along depth and salinity gradients. Dissolved oxygen flu...

EVALUATING THE ROLE OF ION COMPOSITION ON THE TOXICITY OF COPPER TO CERIODAPHNIA DUBIA IN VERY HARD WATERS

EPA Science Inventory

The mitigating effect of increasing hardness on metal toxicity is reflected in water quality criteria in the United States. - - - Copper toxicity did not consistently vary as a function of hardness, but likely as a function of other water quality characteristics (e.g. alkalinity ...

Evaluation of copper toxicity using site specific algae and water chemistry: Field validation of laboratory bioassays.

PubMed

Fawaz, Elyssa G; Salam, Darine A; Kamareddine, Lina

2018-07-15

Studies of metal toxicity to microalgae have predominantly been conducted using single non-target algae species and without due regard for the chemistry of the treated waters, leading to ineffective or excessive algaecide treatments. In this study, indigenous multi-algal species (Scenedesmus quadricauda, and Scenedesmus subspicatus and Oscillatoria agardhii) were used in laboratory toxicity bioassays under simulated field water chemistry (pH = 7.2, hardness = 196 mg L -1 as CaCO 3 , and alkalinity = 222 mg L -1 as CaCO 3 ) to determine the optimum copper sulfate treatment dose to control algae growth in an irrigation canal. Toxicity bioassays were conducted using copper sulfate in chelated (with EDTA) and non-chelated (without EDTA) forms to assess the influence of the use of synthetic chelators in toxicity studies. Also, copper toxicity to the indigenous algae species was measured in the non-modified EPA test medium (pH = 7.5, hardness = 92 mg L -1 as CaCO 3 , alkalinity = 10 mg L -1 as CaCO 3 and EDTA= 300 µg L -1 ) to assess the impact of the water chemistry on algae inhibitory algal dosages. Under simulated water chemistry conditions, lower toxicity was measured in the test flasks with the chelated form of copper (96 h- EC 50 = 386.67 µg L -1 as Cu) as compared to those with the non-chelated metal (96 h-EC 50 = 217.17 µg L -1 as Cu). In addition, higher copper toxicity was measured in the test flasks prepared with the non-modified EPA medium using chelated copper (96 h-EC 50 = 65.93 µg L -1 as Cu) as compared to their analogous microcosms with modified water chemistry (96 h-EC 50 = 386.67 µg L -1 as Cu), the increased water hardness and alkalinity in the latter case contributing to the decrease of the metal bioavailability. Results from laboratory experiments showed good correlation with copper dosages used in a small scale field testing to control algae growth, increasing confidence in

Preparation of diclofenac-imprinted polymer beads for selective molecular separation in water.

PubMed

Zhou, Tongchang; Kamra, Tripta; Ye, Lei

2018-03-01

Molecular imprinting technique is an attractive strategy to prepare materials for target recognition and rapid separation. In this work, a new type of diclofenac (DFC)-imprinted polymer beads was synthesized by Pickering emulsion polymerization using 2-(dimethylamino)ethyl methacrylate as the functional monomer. The selectivity and capacity of the molecularly imprinted polymers (MIPs) were investigated in aqueous solution. Equilibrium binding results show that the MIPs have a high selectivity to bind DFC in a wide range of pH values. Moreover, in liquid chromatography experiment, the imprinted polymer beads were packed into column to investigate the binding selectivity under nonequilibrium conditions. The retention time of DFC on the MIP column is significantly longer than its structural analogues. Also, retention of DFC on the MIP column was significantly longer than on the nonimprinted polymer column under aqueous condition. As the new MIP beads can be used to achieve direct separation of DFC from water, the synthetic method and the affinity beads developed in this work opened new possibilities for removing toxic chemicals from environmental and drinking water. Copyright © 2017 John Wiley & Sons, Ltd.

Calculating the Diffusive Flux of Persistent Organic Pollutants between Sediments and the Water Column on the Palos Verdes Shelf Superfund Site using Polymeric Passive Samplers

EPA Science Inventory

Passive samplers were used to determine water concentrations of persistent organic pollutants (POPs) in the surface sediments and near-bottom water of a marine Superfund site on the Palos Verdes Shelf, California, USA. Measured concentrations in the porewater and water column at...

Monitoring of potentially toxic cyanobacteria using an online multi-probe in drinking water sources.

PubMed

Zamyadi, A; McQuaid, N; Prévost, M; Dorner, S

2012-02-01

Toxic cyanobacteria threaten the water quality of drinking water sources across the globe. Two such water bodies in Canada (a reservoir on the Yamaska River and a bay of Lake Champlain in Québec) were monitored using a YSI 6600 V2-4 (YSI, Yellow Springs, Ohio, USA) submersible multi-probe measuring in vivo phycocyanin (PC) and chlorophyll-a (Chl-a) fluorescence, pH, dissolved oxygen, conductivity, temperature, and turbidity in parallel. The linearity of the in vivo fluorescence PC and Chl-a probe measurements were validated in the laboratory with Microcystis aeruginosa (r(2) = 0.96 and r(2) = 0.82 respectively). Under environmental conditions, in vivo PC fluorescence was strongly correlated with extracted PC (r = 0.79) while in vivo Chl-a fluorescence had a weaker relationship with extracted Chl-a (r = 0.23). Multiple regression analysis revealed significant correlations between extracted Chl-a, extracted PC and cyanobacterial biovolume and in vivo fluorescence parameters measured by the sensors (i.e. turbidity and pH). This information will help water authorities select the in vivo parameters that are the most useful indicators for monitoring cyanobacteria. Despite highly toxic cyanobacterial bloom development 10 m from the drinking water treatment plant's (DWTP) intake on several sampling dates, low in vivo PC fluorescence, cyanobacterial biovolume, and microcystin concentrations were detected in the plant's untreated water. The reservoir's hydrodynamics appear to have prevented the transport of toxins and cells into the DWTP which would have deteriorated the water quality. The multi-probe readings and toxin analyses provided critical evidence that the DWTP's untreated water was unaffected by the toxic cyanobacterial blooms present in its source water.

Implication of global environmental changes on chemical toxicity-effect of water temperature, pH, and ultraviolet B irradiation on acute toxicity of several pharmaceuticals in Daphnia magna.

PubMed

Kim, Jungkon; Park, Jeongim; Kim, Pan-Gyi; Lee, Chulwoo; Choi, Kyunghee; Choi, Kyungho

2010-04-01

Global environmental change poses emerging environmental health challenges throughout the world. One of such threats could be found in chemical safety in aquatic ecosystem. In the present study, we evaluated the effect of several environmental factors, such as water pH, temperature and ultraviolet light on the toxicity of pharmaceutical compounds in water, using freshwater invertebrate Daphnia magna. Seven pharmaceuticals including ibuprofen, acetaminophen, lincomycin, ciprofloxacin, enrofloxacin, chlortetracycline and sulfathiazole were chosen as test compounds based on their frequent detection in water. The experimental conditions of environmental parameters were selected within the ranges that could be encountered in temperate environment, i.e., water temperature (15, 21, and 25 degrees C), pH (7.4, 8.3, and 9.2), and UV-B light intensity (continuous irradiation of 15.0 microW/cm(2)). For acetaminophen, enrofloxacin and sulfathiazole, decrease in water pH generally led to increase of acute lethal toxicity, which could be explained by the unionized fraction of pharmaceuticals. Increase of water temperature enhanced the acute toxicity of the acetaminophen, enrofloxacin and chlortetracycline, potentially due to alteration in toxicokinetics of chemicals as well as impact on physiological mechanisms of the test organism. The presence of UV-B light significantly increased the toxicity of sulfathiazole, which could be explained by photo-modification of this chemical that lead to oxidative stress. Under the UV light, however, acute toxicity of enrofloxacin decreased, which might be due to photo-degradation. Since changing environmental conditions could affect exposure and concentration-response profile of environmental contaminants, such conditions should be identified and evaluated in order to better manage ecosystem health under changing global environment.

Influence of pycnocline topography and water-column structure on marine distributions of alcids (Aves: Alcidae) in Anadyr Strait, Northern Bering Sea, Alaska

USGS Publications Warehouse

Haney, J. Christopher

1991-01-01

Systematic ship-board surveys were used to simultaneously record seabird abundances and resolve coarse-scale (3 to 10 km) horizontal and fine-scale (1 to 10 m) vertical variability in water-column structure and bathymetry for portions of the coastal zone in Anadyr Strait near western St. Lawrence Island, northern Bering Sea, Alaska, during August and September 1987. Three plankton-feeding alcids, parakeet (Cyclorrhynchus psittacula), crested (Aethia cristatella) and least (A. pusilla) auklets, each exhibited distinct associations for different pycnocline characteristics. Least auklets were more abundant in mixed water, but they also occurred within stratified water where the pycnocline and upper-mixed layer were shallow (≤8 m) and thin (≤10 m), respectively. Low body mass (85 g), high buoyancy, and relatively poor diving ability may have restricted this auklet to areas where water-column strata nearly intersected the surface, or to areas from which strata were absent altogether due to strong vertical mixing. Parakeet and crested auklets, which are larger-bodied (ca. 260 g) planktivores with presumably greater diving ability, were more abundant in stratified water, and both species exhibited less specific affinities for water-column characteristic at intermediate and shallow levels. All three auklets avoided locations with strong pycnocline gradients (≤0.22σtm−1), a crude index of the strong, subsurface shear in water velocities characteristic of this region. Auklet distributions in Anadyr Strait were consistent with: (1) strata accessibility, as estimated from relationships between body mass and relative diving ability, (2) possible avoidance of strong subsurface water motions, and (3) habits and distributions of plankton prey. In contrast, largebodied (>450 g) alcids [i.e., common (Uria aalge) and thick-billed (U. lomvia) murres, pigeon guillemots (Cephus columba), tufted (Fratercula cirrhata), and horned (F. corniculata) puffins feeding on fish or

Toxicity evaluation of process water from hydrothermal carbonization of sugarcane industry by-products.

PubMed

Fregolente, Laís Gomes; Miguel, Thaiz Batista Azevedo Rangel; de Castro Miguel, Emilio; de Almeida Melo, Camila; Moreira, Altair Benedito; Ferreira, Odair Pastor; Bisinoti, Márcia Cristina

2018-03-29

Hydrothermal carbonization (HTC) is a thermochemical process carried out in an aqueous medium. It is capable of converting biomass into a solid, carbon-rich material (hydrochar), and producing a liquid phase (process water) which contains the unreactive feedstock and/or chemical intermediates from the carbonization reaction. The aim of this study was to evaluate the characteristics of process water generated by HTC from vinasse and sugarcane bagasse produced by sugarcane industry and to evaluate its toxicity to both marine (using Artemia salina as a model organism) and the terrestrial environment (through seed germination studies of maize, lettuce, and tomato). The experiments showed that concentrated process water completely inhibited germination of maize, lettuce, and tomato seeds. On the other hand, diluted process water was able to stimulate seedlings of maize and tomato and enhance root and shoot growth. For Artemia, the LC 50 indicated that the process water is practically non-toxic; however, morphological changes, especially damages to the digestive tube and antennas of Artemia, were observed for the concentration of 1000 mg C L -1 .

Methane release from sediment seeps to the atmosphere is counteracted by highly active Methylococcaceae in the water column of deep oligotrophic Lake Constance.

PubMed

Bornemann, Maren; Bussmann, Ingeborg; Tichy, Lucas; Deutzmann, Jörg; Schink, Bernhard; Pester, Michael

2016-08-01

Methane emissions from freshwater environments contribute substantially to global warming but are under strong control of aerobic methane-oxidizing bacteria. Recently discovered methane seeps (pockmarks) in freshwater lake sediments have the potential to bypass this control by their strong outgassing activity. Whether this is counteracted by pelagic methanotrophs is not well understood yet. We used a (3)H-CH4-radiotracer technique and pmoA-based molecular approaches to assess the activity, abundance and community structure of pelagic methanotrophs above active pockmarks in deep oligotrophic Lake Constance. Above profundal pockmarks, methane oxidation rates (up to 458 nmol CH4 l(-1) d(-1)) exceeded those of the surrounding water column by two orders of magnitude and coincided with maximum methanotroph abundances of 0.6% of the microbial community. Phylogenetic analysis indicated a dominance of members of the Methylococcaceae in the water column of both, pockmark and reference sites, with most of the retrieved sequences being associated with a water-column specific clade. Communities at pockmark and reference locations also differed in parts, which was likely caused by entrainment of sediment-hosted methanotrophs at pockmark sites. Our results show that the release of seep-derived methane to the atmosphere is counteracted by a distinct methanotrophic community with a pronounced activity throughout bottom waters. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Biocolloid transport in water saturated columns packed with sand

NASA Astrophysics Data System (ADS)

Syngouna, V. I.; Chrysikopoulos, C.

2010-12-01

Protection of groundwater supplies from microbial contamination necessitates a solid understanding of the factors controlling the migration and retention of pathogenic organisms (biocolloids) in the subsurface. The transport behavior of three waterborne pathogens (Escherichia coli, MS2, and ΦΧ174) was investigated using laboratory-scale columns packed with clean quartz sand. Various grain sizes and pore water velocities were examined. Though coliform bacteria and coliphages are used worldwide to indicate fecal pollution of groundwater, the various parameters controlling the transport of Escherichia coli MS2 and ΦΧ174 in the subsurface are not fully understood. In this study, the attachment behavior of Escherichia coli, MS2, and ΦΧ174 onto ultra-pure quartz sand were evaluated. The mass recoveries of the three biocolloids examined were found to be proportional to the sand size. The observed mass recoveries were in the order: Escherichia coli > ΦΧ174 > MS2. To assess the importance of biocolloid attachment, the single collector removal efficiency, and the collision efficiency were quantified using the classical colloid filtration theory. Our results indicate that the secondary energy minimum plays an important role in biocolloid deposition even for smaller biocolloid particles (e.g. viruses).

Dissolved methane concentrations in the water column and surface sediments of Hanna Shoal and Barrow Canyon, Northern Chukchi Sea

NASA Astrophysics Data System (ADS)

Lapham, Laura; Marshall, Kathleen; Magen, Cédric; Lyubchich, Viacheslav; Cooper, Lee W.; Grebmeier, Jacqueline M.

2017-10-01

Current estimates of methane (CH4) flux suggest that Arctic shelves may be a significant source of atmospheric CH4, a potent greenhouse gas. However, little information is known about the CH4 flux from most Arctic shelves, other than the East Siberian Arctic Shelf. We report here dissolved CH4 concentrations in the water column and within surface sediments of the Northern Chukchi Sea. We hypothesized that this area contains high concentrations of CH4 because it receives nutrient rich waters through the Bering Strait, promoting primary production that enhances an organic-rich material flux to the seafloor and eventual microbial methanogenesis in the sediments. In August 2012, as part of the Chukchi Sea Offshore Monitoring in Drilling Area (COMIDA) project, fourteen stations were sampled on Hanna Shoal, a shallow feature on the shelf, and ten stations across the undersea Barrow Canyon. On Hanna Shoal, water column CH4 concentrations ranged from 14 to 74 nM, and surface concentrations were up to 15 times supersaturated in CH4 compared to equilibrium with the average atmospheric concentrations (3 nM). CH4 concentrations at the sediment-water interface were around 1,500 nM, and typically increased with depth in the sediment. At the head of Barrow Canyon, water column CH4 concentrations ranged from 5 to 46 nM, with the highest concentrations in the deepest waters that were sampled (118 m). Overall, the calculated fluxes to the atmosphere ranged from 1 to 80 μmol CH4 m-2 d-1 for Hanna Shoal and 4 to 17 μmol CH4 m-2 d-1 across the Barrow Canyon stations. Although there was a large range in these fluxes, the average atmospheric flux (20 μmol CH4 m-2 d-1) across Hanna Shoal was 12 times lower than the flux reported from the East Siberian Arctic Shelf in summer. We conclude that while there is a positive flux of CH4 to the atmosphere, this part of the Chukchi Sea is not a significant source of atmospheric CH4 compared to the East Siberian Sea shelf.

Technical Note: Detection of gas bubble leakage via correlation of water column multibeam images

NASA Astrophysics Data System (ADS)

Schneider von Deimling, J.; Papenberg, C.

2012-03-01

Hydroacoustic detection of natural gas release from the seafloor has been conducted in the past by using singlebeam echosounders. In contrast, modern multibeam swath mapping systems allow much wider coverage, higher resolution, and offer 3-D spatial correlation. Up to the present, the extremely high data rate hampers water column backscatter investigations and more sophisticated visualization and processing techniques are needed. Here, we present water column backscatter data acquired with a 50 kHz prototype multibeam system over a period of 75 seconds. Display types are of swath-images as well as of a "re-sorted" singlebeam presentation. Thus, individual and/or groups of gas bubbles rising from the 24 m deep seafloor clearly emerge in the acoustic images, making it possible to estimate rise velocities. A sophisticated processing scheme is introduced to identify those rising gas bubbles in the hydroacoustic data. We apply a cross-correlation technique adapted from particle imaging velocimetry (PIV) to the acoustic backscatter images. Temporal and spatial drift patterns of the bubbles are assessed and are shown to match very well to measured and theoretical rise patterns. The application of this processing to our field data gives clear results with respect to unambiguous bubble detection and remote bubble rise velocimetry. The method can identify and exclude the main source of misinterpretations, i.e. fish-mediated echoes. Although image-based cross-correlation techniques are well known in the field of fluid mechanics for high resolution and non-inversive current flow field analysis, we present the first application of this technique as an acoustic bubble detector.

Evaluation of acute copper toxicity to juvenile freshwater mussels (fatmucket, lampsilis siliquoidea) in natural and reconstituted waters

USGS Publications Warehouse

Wang, N.; Mebane, C.A.; Kunz, J.L.; Ingersoll, C.G.; May, T.W.; Arnold, W.R.; Santore, R.C.; Augspurger, T.; Dwyer, F.J.; Barniiart, M.C.

2009-01-01

The influence of dissolved organic carbon (DOC) and water composition on the toxicity of copper to juvenile freshwater mussels (fatmucket, Lampsilis siliquoidea) were evaluated in natural and reconstituted waters. Acute 96-h copper toxicity tests were conducted at four nominal DOC concentrations (0, 2.5, 5, and 10 mg/L as carbon [C]) in dilutions of natural waters and in American Society for Testing and Materials (ASTM) reconstituted hard water. Toxicity tests also were conducted in ASTM soft, moderately hard, hard, and very hard reconstituted waters (nominal hardness 45-300 mg/L as CaCO3). Three natural surface waters (9.5-11 mg/L DOC) were diluted to obtain a series of DOC concentrations with diluted well water, and an extract of natural organic matter and commercial humic acid was mixed with ASTM hard water to prepare a series of DOC concentrations for toxicity testing. Median effective concentrations (EC50s) for dissolved copper varied >40-fold (9.9 to >396 ??g Cu/L) over all 21 treatments in various DOC waters. Within a particular type of DOC water, EC50s increased 5- to 12-fold across DOC concentrations of 0.3 to up to 11 mg C/L. However, EC50s increased by only a factor of 1.4 (21 30 ??g Cu/L) in the four ASTM waters with wide range of water hardness (52-300 mg CaCO 3/L). Predictions from the biotic ligand model (BLM) for copper explained nearly 90% of the variability in EC50s. Nearly 70% of BLM-normalized EC50s for fatmucket tested in natural waters were below the final acute value used to derive the U.S. Environmental Protection Agency acute water quality criterion for copper, indicating that the criterion might not be protective of fatmucket and perhaps other mussel species. ?? 2009 SETAC.

Short-range precipitation forecasts using assimilation of simulated satellite water vapor profiles and column cloud liquid water amounts

NASA Technical Reports Server (NTRS)

Wu, Xiaohua; Diak, George R.; Hayden, Cristopher M.; Young, John A.

1995-01-01

These observing system simulation experiments investigate the assimilation of satellite-observed water vapor and cloud liquid water data in the initialization of a limited-area primitive equations model with the goal of improving short-range precipitation forecasts. The assimilation procedure presented includes two aspects: specification of an initial cloud liquid water vertical distribution and diabatic initialization. The satellite data is simulated for the next generation of polar-orbiting satellite instruments, the Advanced Microwave Sounding Unit (AMSU) and the High-Resolution Infrared Sounder (HIRS), which are scheduled to be launched on the NOAA-K satellite in the mid-1990s. Based on cloud-top height and total column cloud liquid water amounts simulated for satellite data a diagnostic method is used to specify an initial cloud water vertical distribution and to modify the initial moisture distribution in cloudy areas. Using a diabatic initialization procedure, the associated latent heating profiles are directly assimilated into the numerical model. The initial heating is estimated by time averaging the latent heat release from convective and large-scale condensation during the early forecast stage after insertion of satellite-observed temperature, water vapor, and cloud water formation. The assimilation of satellite-observed moisture and cloud water, together withy three-mode diabatic initialization, significantly alleviates the model precipitation spinup problem, especially in the first 3 h of the forecast. Experimental forecasts indicate that the impact of satellite-observed temperature and water vapor profiles and cloud water alone in the initialization procedure shortens the spinup time for precipitation rates by 1-2 h and for regeneration of the areal coverage by 3 h. The diabatic initialization further reduces the precipitation spinup time (compared to adiabatic initialization) by 1 h.

Evaluation of the boundary condition influence on PAH concentrations in the water column during the sediment dredging of a port.

PubMed

Cutroneo, L; Castellano, M; Carbone, C; Consani, S; Gaino, F; Tucci, S; Magrì, S; Povero, P; Bertolotto, R M; Canepa, G; Capello, M

2015-12-30

The mobilisation of sediments and related contaminants connected to dredging activities is one of the most critical issues to the environmental risk and exposure assessment of a dredging project. The aim of this paper was an investigation of the mobilisation of polycyclic aromatic hydrocarbons (PAHs) due to the dredging of the Port of Genoa (Italy) to identify the temporal and spatial extent of the contaminant transport, and the influence of the dredging and the boundary conditions on it. The results showed relatively low background PAH concentrations in the water column and confirmed the dredging as the primary rising factor of concentrations in the water column, but also showed a complex scenario in which the different environmental and dredging factors forced the concentrations at different levels and moments. The post dredging phase showed PAH values close to the background conditions and the concentrations remained relatively high only for a few PAHs.

SURFACTANT ENHANCED REMEDIATION OF SOIL COLUMNS CONTAMINATED BY RESIDUAL TETRACHLOROETHYLENE

EPA Science Inventory

The ability of aqueous surfactant solutions to recover tetrachloroethylene (PCE) entrapped in Ottawa sand was evaluated in four column experiments. Residual PCE was emplaced by injecting ¹⁴C-labeled PCE into water-saturated soil columns and displacing the free product ...

Trophic state and toxic cyanobacteria density in optimization modeling of multi-reservoir water resource systems.

PubMed

Sulis, Andrea; Buscarinu, Paola; Soru, Oriana; Sechi, Giovanni M

2014-04-22

The definition of a synthetic index for classifying the quality of water bodies is a key aspect in integrated planning and management of water resource systems. In previous works [1,2], a water system optimization modeling approach that requires a single quality index for stored water in reservoirs has been applied to a complex multi-reservoir system. Considering the same modeling field, this paper presents an improved quality index estimated both on the basis of the overall trophic state of the water body and on the basis of the density values of the most potentially toxic Cyanobacteria. The implementation of the index into the optimization model makes it possible to reproduce the conditions limiting water use due to excessive nutrient enrichment in the water body and to the health hazard linked to toxic blooms. The analysis of an extended limnological database (1996-2012) in four reservoirs of the Flumendosa-Campidano system (Sardinia, Italy) provides useful insights into the strengths and limitations of the proposed synthetic index.

STURM: Resuspension mesocosms with realistic bottom shear stress and water column turbulence for benthic-pelagic coupling studies: Design and Applications

NASA Astrophysics Data System (ADS)

Sanford, L. P.; Porter, E.; Porter, F. S.; Mason, R. P.

2016-02-01

Shear TUrbulence Resuspension Mesocosm (STURM) tanks, with high instantaneous bottom shear stress and realistic water column mixing in a single system, allow more realistic benthic-pelagic coupling studies that include sediment resuspension. The 1 m3 tanks can be programmed to produce tidal or episodic sediment resuspension over extended time periods (e.g. 4 weeks), over muddy sediments with or without infaunal organisms. The STURM tanks use a resuspension paddle that produces uniform bottom shear stress across the sediment surface while gently mixing a 1 m deep overlying water column. The STURM tanks can be programmed to different magnitudes, frequencies, and durations of bottom shear stress (and thus resuspension) with proportional water column turbulence levels over a wide range of mixing settings for benthic-pelagic coupling experiments. Over eight STURM calibration settings, turbulence intensity ranged from 0.55 to 4.52 cm s-1, energy dissipation rate from 0.0032 to 2.65 cm2 s-3, the average bottom shear stress from 0.0068 to 0.19 Pa, and the instantaneous bottom shear stress from 0.07 to 2.0 Pa. Mixing settings can be chosen as desired and/or varied over the experiment, based on the scientific question at hand. We have used the STURM tanks for four 4-week benthic-pelagic coupling ecosystem experiments with tidal resuspension with or without infaunal bivalves, for stepwise erosion experiments with and without infaunal bivalves, for experiments on oyster biodeposit resuspension, to mimic storms overlain on tidal resuspension, and for experiments on the effects of varying frequency and duration of resuspension on the release of sedimentary contaminants. The large size of the tanks allows water quality and particle measurements using standard oceanographic instrumentation. The realistic scale and complexity of the contained ecosystems has revealed indirect feedbacks and responses that are not observable in smaller, less complex experimental systems.

HILIC separation and quantitation of water-soluble vitamins using diol column.

PubMed

Karatapanis, Andreas E; Fiamegos, Yiannis C; Stalikas, Constantine D

2009-04-01

Hydrophilic interaction liquid-chromatography (HILIC) in conjunction with diode array detection has been applied for the separation of selected-water-soluble vitamins using an end-capped HILIC-diol column. Vitamins with significant biological importance, such as thiamine (B(1)), riboflavin (B(2)), nicotinic acid (B(3)), nicotinamide (B(3)), pyridoxine (B(6)), folic acid (B(9)), cyanocobalamin (B(12)) and ascorbic acid (vitamin C) were simultaneously separated. Chromatographic conditions including type and percentage of organic modifier in the mobile phase, pH, type and concentration of buffer salt and flow rate were investigated. ACN was shown to offer superior separation for the compounds tested as compared to methanol, isopropanol and THF. Isocratic separation and analysis were achieved for six vitamins (B(1), B(2), nicotinic acid/nicotinamide, B(6) and C) at ACN-H(2)O 90:10, containing ammonium acetate 10 mM, triethylamine 20 mM, pH 5.0, using a flow rate of 0.8 mL/min, while a gradient was necessary to resolve a mixture of all eight water-soluble vitamins. The HILIC method was validated and successfully applied to the analysis of a pharmaceutical formulation and an energy drink negating the need for time consuming clean-up steps.

Comparison of neptunium sorption results using batch and column techniques

DOE Office of Scientific and Technical Information (OSTI.GOV)

Triay, I.R.; Furlano, A.C.; Weaver, S.C.

1996-08-01

We used crushed-rock columns to study the sorption retardation of neptunium by zeolitic, devitrified, and vitric tuffs typical of those at the site of the potential high-level nuclear waste repository at Yucca Mountain, Nevada. We used two sodium bicarbonate waters (groundwater from Well J-13 at the site and water prepared to simulate groundwater from Well UE-25p No. 1) under oxidizing conditions. It was found that values of the sorption distribution coefficient, Kd, obtained from these column experiments under flowing conditions, regardless of the water or the water velocity used, agreed well with those obtained earlier from batch sorption experiments undermore » static conditions. The batch sorption distribution coefficient can be used to predict the arrival time for neptunium eluted through the columns. On the other hand, the elution curves showed dispersivity, which implies that neptunium sorption in these tuffs may be nonlinear, irreversible, or noninstantaneous. As a result, use of a batch sorption distribution coefficient to calculate neptunium transport through Yucca Mountain tuffs would yield conservative values for neptunium release from the site. We also noted that neptunium (present as the anionic neptunyl carbonate complex) never eluted prior to tritiated water, which implies that charge exclusion does not appear to exclude neptunium from the tuff pores. The column experiments corroborated the trends observed in batch sorption experiments: neptunium sorption onto devitrified and vitric tuffs is minimal and sorption onto zeolitic tuffs decreases as the amount of sodium and bicarbonate/carbonate in the water increases.« less

Toxic effects of butyl elastomers on aerobic methane oxidation

NASA Astrophysics Data System (ADS)

Niemann, Helge; Steinle, Lea I.; Blees, Jan H.; Krause, Stefan; Bussmann, Ingeborg; Lehmann, Moritz F.; Treude, Tina

2013-04-01

Large quantities of the potent greenhouse gas methane are liberated into the water column of marine and lacustrine environments where it may be consumed by aerobic methane oxidising bacteria before reaching the atmosphere.The reliable quantification of aerobic methane oxidation (MOx) rates is consequently of paramount importance for estimating methane budgets and to understand the controls on water column methane cycling. A widely used set of methods for measuring MOx rates is based on the incubation of water samples during which the consumption of methane is monitored, for instance with radio-tracer assays. Typically, incubation vessels are sealed with butyl rubber stoppers because these elastomers are essentially impermeable for gases at the relevant time scales. We tested the effect of different stopper materials (unmodified- and halogenated butyl rubber) on MOx activity in environmental samples and in cultures of methane oxidising bacteria. MOx rates in samples sealed with unmodified butyl rubber were > 75% lower compared to parallel incubations with halogenated butyl rubber seals, suggesting inhibiting/toxic effects associated with the use of unmodified butyl elastomers. To further explore the cause of these effects, we analysed aqueous extracts of the different stoppers. Halogenated butyl rubber stoppers appeared to bleed off comparably little amounts of organics. In stark contrast, extracts of unmodified butyl rubber were contaminated with various organic compounds including potential bactericides such as benzyltoluenes, phenylalkanes and benzuothiazoles. We also found tetramethylthiourea, a scavenger of active oxygen species, which may inhibit the MOx pathway.

High-Accuracy Measurements of Total Column Water Vapor From the Orbiting Carbon Observatory-2

NASA Technical Reports Server (NTRS)

Nelson, Robert R.; Crisp, David; Ott, Lesley E.; O'Dell, Christopher W.

2016-01-01

Accurate knowledge of the distribution of water vapor in Earth's atmosphere is of critical importance to both weather and climate studies. Here we report on measurements of total column water vapor (TCWV) from hyperspectral observations of near-infrared reflected sunlight over land and ocean surfaces from the Orbiting Carbon Observatory-2 (OCO-2). These measurements are an ancillary product of the retrieval algorithm used to measure atmospheric carbon dioxide concentrations, with information coming from three highly resolved spectral bands. Comparisons to high-accuracy validation data, including ground-based GPS and microwave radiometer data, demonstrate that OCO-2 TCWV measurements have maximum root-mean-square deviations of 0.9-1.3mm. Our results indicate that OCO-2 is the first space-based sensor to accurately and precisely measure the two most important greenhouse gases, water vapor and carbon dioxide, at high spatial resolution [1.3 x 2.3 km(exp. 2)] and that OCO-2 TCWV measurements may be useful in improving numerical weather predictions and reanalysis products.

Behavioral, clinical, and pathological characterization of acid metalliferous water toxicity in mallards

USGS Publications Warehouse

Isanhart, J.P.; Wu, H.; Pandher, K.; MacRae, R.K.; Cox, S.B.; Hooper, M.J.

2011-01-01

From September to November 2000, United States Fish and Wildlife Service biologists investigated incidents involving 221 bird deaths at 3 mine sites located in New Mexico and Arizona. These bird deaths primarily involved passerine and waterfowl species and were assumed to be linked to consumption of acid metalliferous water (AMW). Because all of the carcasses were found in or near pregnant leach solution ponds, tailings ponds, and associated lakes or storm water retention basins, an acute-toxicity study was undertaken using a synthetic AMW (SAMW) formulation based on the contaminant profile of a representative pond believed to be responsible for avian mortalities. An acute oral-toxicity trial was performed with a mixed-sex group of mallards (Anas platyrhynchos). After a 24-h pretreatment food and water fast, gorge drinking was evident in both SAMW treatment and control groups, with water consumption rates greatest during the initial drinking periods. Seven of nine treated mallards were killed in extremis within 12 h after the initiation of dose. Total lethal doses of SAMW ranged from 69.8 to 270.1 mL/kg (mean ?? SE 127.9 ?? 27.1). Lethal doses of SAMW were consumed in as few as 20 to 40 min after first exposure. Clinical signs of SAMW toxicity included increased serum uric acid, aspartate aminotransferase, creatine kinase, potassium, and P levels. PCV values of SAMW-treated birds were also increased compared with control mallards. Histopathological lesions were observed in the esophagus, proventriculus, ventriculus, and duodenum of SAMW-treated mallards, with the most distinctive being erosion and ulceration of the kaolin of the ventriculus, ventricular hemorrhage and/or congestion, and duodenal hemorrhage. Clinical, pathological, and tissue-residue results from this study are consistent with literature documenting acute metal toxicosis, especially copper (Cu), in avian species and provide useful diagnostic profiles for AMW toxicity or mortality events. Blood and

Behavioral, clinical, and pathological characterization of acid metalliferous water toxicity in mallards

USGS Publications Warehouse

Isanhart, John P.; Wu, Hongmei; Pandher, Karamjeet; MacRae, Russell K.; Cox, Stephen B.; Hooper, Michael J.

2011-01-01

From September to November 2000, United States Fish and Wildlife Service biologists investigated incidents involving 221 bird deaths at 3 mine sites located in New Mexico and Arizona. These bird deaths primarily involved passerine and waterfowl species and were assumed to be linked to consumption of acid metalliferous water (AMW). Because all of the carcasses were found in or near pregnant leach solution ponds, tailings ponds, and associated lakes or storm water retention basins, an acute-toxicity study was undertaken using a synthetic AMW (SAMW) formulation based on the contaminant profile of a representative pond believed to be responsible for avian mortalities. An acute oral-toxicity trial was performed with a mixed-sex group of mallards (Anas platyrhynchos). After a 24-h pretreatment food and water fast, gorge drinking was evident in both SAMW treatment and control groups, with water consumption rates greatest during the initial drinking periods. Seven of nine treated mallards were killed in extremis within 12 h after the initiation of dose. Total lethal doses of SAMW ranged from 69.8 to 270.1 mL/kg (mean ± SE 127.9 ± 27.1). Lethal doses of SAMW were consumed in as few as 20 to 40 min after first exposure. Clinical signs of SAMW toxicity included increased serum uric acid, aspartate aminotransferase, creatine kinase, potassium, and P levels. PCV values of SAMW-treated birds were also increased compared with control mallards. Histopathological lesions were observed in the esophagus, proventriculus, ventriculus, and duodenum of SAMW-treated mallards, with the most distinctive being erosion and ulceration of the kaolin of the ventriculus, ventricular hemorrhage and/or congestion, and duodenal hemorrhage. Clinical, pathological, and tissue-residue results from this study are consistent with literature documenting acute metal toxicosis, especially copper (Cu), in avian species and provide useful diagnostic profiles for AMW toxicity or mortality events. Blood and

Behavioral, clinical, and pathological characterization of acid metalliferous water toxicity in mallards.

PubMed

Isanhart, John P; Wu, Hongmei; Pandher, Karamjeet; MacRae, Russell K; Cox, Stephen B; Hooper, Michael J

2011-11-01

From September to November 2000, United States Fish and Wildlife Service biologists investigated incidents involving 221 bird deaths at 3 mine sites located in New Mexico and Arizona. These bird deaths primarily involved passerine and waterfowl species and were assumed to be linked to consumption of acid metalliferous water (AMW). Because all of the carcasses were found in or near pregnant leach solution ponds, tailings ponds, and associated lakes or storm water retention basins, an acute-toxicity study was undertaken using a synthetic AMW (SAMW) formulation based on the contaminant profile of a representative pond believed to be responsible for avian mortalities. An acute oral-toxicity trial was performed with a mixed-sex group of mallards (Anas platyrhynchos). After a 24-h pretreatment food and water fast, gorge drinking was evident in both SAMW treatment and control groups, with water consumption rates greatest during the initial drinking periods. Seven of nine treated mallards were killed in extremis within 12 h after the initiation of dose. Total lethal doses of SAMW ranged from 69.8 to 270.1 mL/kg (mean ± SE 127.9 ± 27.1). Lethal doses of SAMW were consumed in as few as 20 to 40 min after first exposure. Clinical signs of SAMW toxicity included increased serum uric acid, aspartate aminotransferase, creatine kinase, potassium, and P levels. PCV values of SAMW-treated birds were also increased compared with control mallards. Histopathological lesions were observed in the esophagus, proventriculus, ventriculus, and duodenum of SAMW-treated mallards, with the most distinctive being erosion and ulceration of the kaolin of the ventriculus, ventricular hemorrhage and/or congestion, and duodenal hemorrhage. Clinical, pathological, and tissue-residue results from this study are consistent with literature documenting acute metal toxicosis, especially copper (Cu), in avian species and provide useful diagnostic profiles for AMW toxicity or mortality events. Blood and

Column with CNT/magnesium oxide composite for lead(II) removal from water.

PubMed

Saleh, Tawfik A; Gupta, Vinod K

2012-05-01

In this study, manganese dioxide-coated multiwall carbon nanotube (MnO(2)/CNT) nanocomposite has been successfully synthesized. The as-produced nanocomposite was characterized by different characteristic tools, such as X-ray diffraction, SEM, and FTIR. The MnO(2)/CNT nanocomposite was utilized as a fixed bed in a column system for removal of lead(II) from water. The experimental conditions were investigated and optimized. The pH range between 3 and 7 was studied; the optimum removal was found when the pH was equal to 6 and 7. The thickness of MnO(2)/CNT nanocomposite compact layer was also changed to find the optimum parameter for higher removal. It was observed that the slower the flow rates of the feed solution the higher the removal because of larger contact time.

Volcanoes in the Classroom: Simulating an Eruption Column

NASA Astrophysics Data System (ADS)

Harpp, K. S.; Geist, D. J.; Koleszar, A. M.

2005-12-01

Few students have the opportunity to witness volcanic eruptions first hand. Analog models of eruptive processes provide ways for students to apply basic physical principles when field observations are not feasible. We describe a safe simulation of violent volcanic explosions, one that can be carried out simply and easily as a demonstration for specialized volcanology classes, introductory classes, and science outreach programs. Volcanic eruptions are fundamentally gas-driven phenomena. Depressurization of volatiles dissolved in magma during ascent is the driving force behind most explosive eruptions. We have developed a demonstration whereby the instructor can initiate a gas-driven eruption, which produces a dramatic but safe explosion and eruptive column. First, one pours liquid nitrogen into a weighted, plastic soda bottle, which is then sealed and placed into a trashcan filled with water. As the liquid nitrogen boils, the pressure inside the bottle increases until the seal fails, resulting in an explosion. The expansive force propels a column of water vertically, to 10 or more meters. Students can operate the demonstration themselves and carry out a sequence of self-designed variations, changing the vent size and viscosity of the "magma", for instance. They can also vary the material used as "tephra", studying the effects of projectile density, column height, and wind direction on tephra distribution. The physical measurements that students collect, such as column height and tephra radius, can be used as the basis for problem sets that explore the dynamics of eruption columns. Possible calculations include ejection velocity, the pressure needed to propel the water column, and average vesicularity of the "magma". Students can then compare their results to observations from real volcanic eruptions. We find this to be an exceedingly effective demonstration of gas-driven liquid explosions and one that is safe if done properly. [NOTE: Please do NOT attempt this

Use of a polar ionic liquid as second column for the comprehensive two-dimensional GC separation of PCBs.

PubMed

Zapadlo, Michal; Krupcík, Ján; Májek, Pavel; Armstrong, Daniel W; Sandra, Pat

2010-09-10

The orthogonality of three columns coupled in two series was studied for the congener specific comprehensive two-dimensional GC separation of polychlorinated biphenyls (PCBs). A non-polar capillary column coated with poly(5%-phenyl-95%-methyl)siloxane was used as the first ((1)D) column in both series. A polar capillary column coated with 70% cyanopropyl-polysilphenylene-siloxane or a capillary column coated with the ionic liquid 1,12-di(tripropylphosphonium)dodecane bis(trifluoromethane-sulfonyl)imide were used as the second ((2)D) columns. Nine multi-congener standard PCB solutions containing subsets of all native 209 PCBs, a mixture of 209 PCBs as well as Aroclor 1242 and 1260 formulations were used to study the orthogonality of both column series. Retention times of the corresponding PCB congeners on (1)D and (2)D columns were used to construct retention time dependences (apex plots) for assessing orthogonality of both columns coupled in series. For a visual assessment of the peak density of PCBs congeners on a retention plane, 2D images were compared. The degree of orthogonality of both column series was, along the visual assessment of distribution of PCBs on the retention plane, evaluated also by Pearson's correlation coefficient, which was found by correlation of retention times t(R,i,2D) and t(R,i,1D) of corresponding PCB congeners on both column series. It was demonstrated that the apolar+ionic liquid column series is almost orthogonal both for the 2D separation of PCBs present in Aroclor 1242 and 1260 formulations as well as for the separation of all of 209 PCBs. All toxic, dioxin-like PCBs, with the exception of PCB 118 that overlaps with PCB 106, were resolved by the apolar/ionic liquid series while on the apolar/polar column series three toxic PCBs overlapped (105+127, 81+148 and 118+106). Copyright 2010 Elsevier B.V. All rights reserved.

Turbulence observations in the Gulf of Trieste under moderate wind forcing and different water column stratification

NASA Astrophysics Data System (ADS)

Marcello Falcieri, Francesco; Kantha, Lakshmi; Benetazzo, Alvise; Bergamasco, Andrea; Bonaldo, Davide; Barbariol, Francesco; Malačič, Vlado; Sclavo, Mauro; Carniel, Sandro

2016-03-01

The oceanographic campaign CARPET2014 (Characterizing Adriatic Region Preconditionig EvenTs), (30 January-4 February 2014) collected the very first turbulence data in the Gulf of Trieste (northern Adriatic Sea) under moderate wind (average wind speed 10 m s-1) and heat flux (net negative heat flux ranging from 150 to 400 W m-2). Observations consisted of 38 CTD (Conductivity, Temperature, Depth) casts and 478 microstructure profiles (grouped into 145 ensembles) with three sets of yoyo casts, each lasting for about 12 consecutive hours. Averaging closely repeated casts, such as the ensembles, can lead to a smearing effect when in the presence of a vertical density structure with strong interfaces that can move up or down between subsequent casts under the influence of tides and internal waves. In order to minimize the smearing effect of such displacements on mean quantities, we developed an algorithm to realign successive microstructure profiles to produce sharper and more meaningful mean profiles of measured turbulence parameters. During the campaign, the water column in the gulf evolved from well-mixed to stratified conditions due to Adriatic waters intruding at the bottom along the gulf's south-eastern coast. We show that during the warm and relatively dry winter, the water column in the Gulf of Trieste, even under moderate wind forcing, was not completely mixed due to the influence of bottom waters intruding from the open sea. Inside the gulf, two types of water intrusions were found during yoyo casts: one coming from the northern coast of the Adriatic Sea (i.e. cooler, fresher and more turbid) and one coming from the open sea in front of the Po Delta (i.e. warmer, saltier and less turbid). The two intrusions had different impacts on turbulence kinetic energy dissipation rate profiles. The former, with high turbidity, acted as a barrier to wind-driven turbulence, while the latter, with low sediment concentrations and a smaller vertical density gradient, was not

Biochar application to hardrock mine tailings: Soil quality, microbial activity, and toxic element sorption

USGS Publications Warehouse

Kelly, Charlene N.; Peltz, Christopher D.; Stanton, Mark R.; Rutherford, David W.; Rostad, Colleen E.

2014-01-01

Waste rock piles from historic mining activities remain unvegetated as a result of metal toxicity and high acidity. Biochar has been proposed as a low-cost remediation strategy to increase soil pH and reduce leaching of toxic elements, and improve plant establishment. In this laboratory column study, biochar made from beetle-killed pine wood was assessed for utility as a soil amendment by mixing soil material from two mine sites collected near Silverton, Colorado, USA with four application rates of biochar (0%, 10%, 20%, 30% vol:vol). Columns were leached seven times over 65 days and leachate pH and concentration of toxic elements and base cations were measured at each leaching. Nutrient availability and soil physical and biological parameters were determined following the incubation period. We investigated the hypotheses that biochar incorporation into acidic mine materials will (1) reduce toxic element concentrations in leaching solution, (2) improve soil parameters (i.e. increase nutrient and water holding capacity and pH, and decrease compaction), and (3) increase microbial populations and activity. Biochar directly increased soil pH (from 3.33 to 3.63 and from 4.07 to 4.77 in the two materials) and organic matter content, and decreased bulk density and extractable salt content in both mine materials, and increased nitrate availability in one material. No changes in microbial population or activity were detected in either mine material upon biochar application. In leachate solution, biochar increased base cations from both materials and reduced the concentrations of Al, Cd, Cu, Pb, and Zn in leachate solution from one material. However, in the material with greater toxic element content, biochar did not reduce concentrations of any measured dissolved toxic elements in leachate and resulted in a potentially detrimental release of Cd and Zn into solution at concentrations above that of the pure mine material. The length of time of effectiveness and specific

The impact of toxic cyanobacteria on the water quality in the Deep Subalpine Lakes (DSL)

NASA Astrophysics Data System (ADS)

Cerasino, Leonardo; Shams, Shiva; Salmaso, Nico; Dietrich, Daniel

2013-04-01

Toxic cyanobacteria represent an emerging threat for aquatic ecosystems worldwide. Eutrophication and climate changes are mentioned among factors favouring toxic blooms. The toxicity of cyanobacteria is related to the ability of some species (the most common in temperate waters belong to the genera Microcystis, Planktothrix, Dolichospermum) of producing a wide variety of toxic secondary metabolites, i.e. microcystins, nodularins, anatoxins, saxitoxins, cylindrospermopsins. Some of these toxins can accumulate in water and aquatic organisms. They can therefore produce severe effects on humans by direct exposure (contact or ingestion of contaminated water) or by indirect exposure (by consumption of contaminated food). We have conducted a survey on the distribution of cyanobacterial toxins in the largest Italian lakes (Garda, Iseo, Como, Maggiore, Lugano), which are important water resources for drinking purposes and for recreational use. Cyanobacterial toxins were present in all lakes, although with a big variability in concentration. More specifically, in the frame of the European project EULAKES, we have investigated in detail the temporal dynamics of the toxin production in Lake Garda, and the mechanisms of trophic transfer of the microcystins along the lacustrine food chain. By applying advanced analytical techniques based on LC-MS technologies, we were able to detect several microcystins at sub-ppb level and follow their variations during the year. The total concentrations of microcystins were strictly linked to the temporal and vertical dynamics of Planktothrix rubescens. Laboratory experiments allowed us to determine the kinetics of microcystin accumulation in zooplankton (daphnia magna).

The effect of the cation alkyl chain branching on mutual solubilities with water and toxicities.

PubMed

Kurnia, Kiki A; Sintra, Tânia E; Neves, Catarina M S S; Shimizu, Karina; Canongia Lopes, José N; Gonçalves, Fernando; Ventura, Sónia P M; Freire, Mara G; Santos, Luís M N B F; Coutinho, João A P

2014-10-07

The design of ionic liquids has been focused on the cation-anion combinations but other more subtle approaches can be used. In this work the effect of the branching of the cation alkyl chain on the design of ionic liquids (ILs) is evaluated. The mutual solubilities with water and toxicities of a series of bis(trifluoromethylsulfonyl)-based ILs, combined with imidazolium, pyridinium, pyrrolidinium, and piperidinium cations with linear or branched alkyl chains, are reported. The mutual solubility measurements were carried out in the temperature range from (288.15 to 323.15) K. From the obtained experimental data, the thermodynamic properties of the solution (in the water-rich phase) were determined and discussed. The COnductor like Screening MOdel for Real Solvents (COSMO-RS) was used to predict the liquid-liquid equilibrium. Furthermore, molecular dynamic simulations were also carried out aiming to get a deeper understanding of these fluids at the molecular level. The results show that the increase in the number of atoms at the cation ring (from five to six) leads to a decrease in the mutual solubilities with water while increasing their toxicity, and as expected from the well-established relationship between toxicities and hydrophobicities of ILs. The branching of the alkyl chain was observed to decrease the water solubility in ILs, while increasing the ILs solubility in water. The inability of COSMO-RS to correctly predict the effect of branching alkyl chains toward water solubility on them was confirmed using molecular dynamic simulations to be due to the formation of nano-segregated structures of the ILs that are not taken into account by the COSMO-RS model. In addition, the impact of branched alkyl chains on the toxicity is shown to be not trivial and to depend on the aromatic nature of the ILs.

An ultra-sensitive method for the analysis of perfluorinated alkyl acids in drinking water using a column switching high-performance liquid chromatography tandem mass spectrometry.

PubMed

Dasu, Kavitha; Nakayama, Shoji F; Yoshikane, Mitsuha; Mills, Marc A; Wright, J Michael; Ehrlich, Shelley

2017-04-21

In epidemiological research, it has become increasingly important to assess subjects' exposure to different classes of chemicals in multiple environmental media. It is a common practice to aliquot limited volumes of samples into smaller quantities for specific trace level chemical analyses. A novel method was developed for the determination of 14 perfluorinated alkyl acids (PFAAs) in small volumes (10mL) of drinking water using off-line solid phase extraction (SPE) pre-treatment followed by on-line pre-concentration on a WAX column before analysis on column-switching high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). In general, large volumes (100-1000mL) have been used for the analysis of PFAAs in drinking water. The current method requires approximately 10mL of drinking water concentrated by using an SPE cartridge and eluted with methanol. A large volume injection of the extract was introduced on to a column-switching HPLC-MS/MS using a mix-mode SPE column for the trace level analysis of PFAAs in water. The recoveries for most of the analytes in the fortified laboratory blanks ranged from 73±14% to 128±5%. The lowest concentration minimum reporting levels (LCMRL) for the 14 PFAAs ranged from 0.59 to 3.4ng/L. The optimized method was applied to a pilot-scale analysis of a subset of drinking water samples from an epidemiological study. These samples were collected directly from the taps in the households of Ohio and Northern Kentucky, United States and the sources of drinking water samples are both surface water and ground water, and supplied by different water distribution facilities. Only five PFAAs, perfluoro-1-butanesulfonic acid (PFBS), perfluoro-1- -hexanesulfonic acid (PFHxS), perfluoro-1-octanesulfonic acid (PFOS), perfluoro-n-heptanoic acid (PFHpA) and perfluoro-n-octanoic acid (PFOA) are detected above the LCMRL values. The median concentrations of these five PFAAs detected in the samples was ≤4.1ng/L with PFOS at 7.6ng

Hysteretic growth and decay of a waterspout column

NASA Astrophysics Data System (ADS)

Naumov, Igor V.; Herrada, Miguel A.; Sharifullin, Bulat R.; Shtern, Vladimir N.

2018-02-01

This work explores a model waterspout: a flow of water and sunflower oil driven by the rotating lid in a sealed vertical cylindrical container. The experiments reveal the hysteretic growth and decay of a water column. The numerical simulations uncover vortex breakdown (VB) in the water and oil flows. As the rotation speeds up, (1) a VB water cell emerges near the bottom center, (2) it expands and occupies almost the entire water volume except a thin layer adjusted to the interface, (3) a VB oil cell emerges and disappears above the interface-axis intersection, (4) the interface rises near the axis, descends at the periphery, and shifts from the sidewall to the bottom, (5) the water touches the lid near the axis and forms a column, extending from the bottom up to the lid. As the rotation decelerates, the process reverses, but the flow states differ from those for the direct process at same rotation speeds. It is argued that the hysteresis is a capillary phenomenon and occurs because the interface-wall contact angle differs in the direct and reverse processes.

Open-tubular capillary electrochromatographic determination of ten sulfonamides in tap water and milk by a metal-organic framework-coated capillary column.

PubMed

Wang, Xuan; Ye, Nengsheng; Hu, Xiaoyu; Liu, Qingye; Li, Jian; Peng, Lin; Ma, Xiaotong

2018-05-25

In this study, a metal-organic framework (MOF), [Mn(cam)(bpy)], was synthesized and characterized by thermogravimetric analysis, scanning electron microscopy, and Fourier transform infrared spectrometry. An open-tubular capillary column was fabricated from [Mn(cam)(bpy)] via the amide coupling method. Ten types of sulfonamides were separated through the fabricated capillary column, which showed a good limits of detection (< 0.07 μg·mL -1 ) and a linear ranges (1-100 μg·mL -1 or 5-100 μg·mL -1 ) with a high correlation coefficients (R 2 > 0.9987). The intra-day, inter-day and column-to-column relative standard deviations (RSDs) in the migration times ranged from 0.44% to 4.87%, and the peak area RSDs ranged from 0.80% to 7.28%. The developed capillary electrochromatography method can be successfully utilized for the determination of sulfonamides in tap water and milk samples. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Total ozone column, aerosol optical depth and precipitable water effects on solar erythemal ultraviolet radiation recorded in Malta.

NASA Astrophysics Data System (ADS)

Bilbao, Julia; Román, Roberto; Yousif, Charles; Mateos, David; Miguel, Argimiro

2013-04-01

The Universities of Malta and Valladolid (Spain) developed a measurement campaign, which took place in the Institute for Energy Technology in Marsaxlokk (Southern Malta) between May and October 2012, and it was supported by the Spanish government through the Project titled "Measurement campaign about Solar Radiation, Ozone, and Aerosol in the Mediterranean area" (with reference CGL2010-12140-E). This campaign provided the first ground-based measurements in Malta of erythemal radiation and UV index, which indicate the effectiveness of the sun exposure to produce sunburn on human skin. A wide variety of instruments was involved in the campaign, providing a complete atmospheric characterization. Data of erythemal radiation and UV index (from UVB-1 pyranometer), total shortwave radiaton (global and diffuse components from CM-6B pyranometers), and total ozone column, aerosol optical thickness, and precitable water column (from a Microtops-II sunphotometer) were available in the campaign. Ground-based and satellite instruments were used in the analysis, and several intercomparisons were carried out to validate remote sensing data. OMI, GOME, GOME-2, and MODIS instruments, which provide data of ozone, aerosol load and optical properties, were used to this end. The effects on solar radiation, ultraviolet and total shortwave ranges, of total ozone column, aerosol optical thickness and precipitable water column were obtained using radiation measurements at different fixed solar zenith angles. The empirical results shown a determinant role of the solar position, a negligible effect of ozone on total shortwave radiation, and a stronger attenuation provided by aerosol particles in the erythemal radiation. A variety of aerosol types from different sources (desert dust, biomass burning, continental, and maritime) reach Malta, in this campaign several dust events from the Sahara desert occurred and were analyzed establishing the air mass back-trajectories ending at Malta at

DISSOLVED ORGANIC CARBON CHARACTERISTICS IN METAL-RICH WATERS AND THE IMPLICATIONS FOR COPPER AQUATIC TOXICITY

EPA Science Inventory

This research will aim to quantify the effects of fractionation between DOC, HFO, HAO, free copper and the behavior of resultant free DOC in the water column on the toxicological effects of copper. Fractionation between DOC, free metals and iron (Fe) and aluminum (Al) hydro...

Visual observations of the vertical distribution of plankton throughout the water column above Broken Spur vent field, Mid-Atlantic Ridge

NASA Astrophysics Data System (ADS)

Vereshchaka, A. L.; Vinogradov, G. M.

1999-09-01

Visual observations were made in September 1997 during the 39 cruise of R/V "Akademik Mstislav Keldysh" with 2 deep-sea manned submersibles "Mir" aboard. During 4 dives the following plankton countings were made: 3 vertical throughout the water column during the day, 2 vertical in the upper 1000 m at night, and 1 oblique in the plume area during the day. Biomass profiles are represented for each dive for all abundant animal groups: copepods, euphausiids+decapods+mysids, chaetognaths, medusae, ctenophores, siphonophores, cyclothones, myctophides, radiolarians, and the total zooplankton. Plankton distribution shows 2 aggregations, one within the main pycnocline and the other near the plume; Gelatinous animals and radiolarians dominate in both aggregations by biomass and make a significant contribution to the plankton biomass throughout the water column. Oblique counting indicates the presence of aggregations of animals near the upper and lower borders of the plume and biomass depletion within the plume core.

Urgent need to reevaluate the latest World Health Organization guidelines for toxic inorganic substances in drinking water.

PubMed

Frisbie, Seth H; Mitchell, Erika J; Sarkar, Bibudhendra

2015-08-13

The World Health Organization (WHO) has established guidelines for drinking-water quality that cover biological and chemical hazards from both natural and anthropogenic sources. In the most recent edition of Guidelines for Drinking-water Quality (2011), the WHO withdrew, suspended, did not establish, or raised guidelines for the inorganic toxic substances manganese, molybdenum, nitrite, aluminum, boron, nickel, uranium, mercury, and selenium. In this paper, we review these changes to the WHO drinking-water guidelines, examining in detail the material presented in the WHO background documents for each of these toxic substances. In some cases, these WHO background documents use literature reviews that do not take into account scientific research published within the last 10 or more years. In addition, there are instances in which standard WHO practices for deriving guidelines are not used; for example, rounding and other mathematical errors are made. According to published meeting reports from the WHO Chemical Aspects Working Group, the WHO has a timetable for revising some of its guidelines for drinking-water quality, but for many of these toxic substances the planned changes are minimal or will be delayed for as long as 5 years. Given the limited nature of the planned WHO revisions to the inorganic toxic substances and the extended timetable for these revisions, we suggest that governments, researchers, and other stakeholders might establish independent recommendations for inorganic toxic substances and possibly other chemicals to proactively protect public health, or at the very least, revert to previous editions of the Guidelines for Drinking-water Quality, which were more protective of public health.

Dynamic behaviour of natural oil droplets through the water column in deep-water environment: the case of the Lower Congo Basin

NASA Astrophysics Data System (ADS)

Jatiault, R.; Dhont, D.; Loncke, L.; Durrieu De Madron, X.; Dubucq, D.; Channelliere, C.; Bourrin, F.

2017-12-01

Key words: Hydrocarbon seepage, Oil Slick, Lower Congo Basin, Underwater deflection, Deep-water Pockmark, Ascent speedThe space-borne imagery provides a significant means to locate active oil seeps and to estimate the expelled volume in the marine environment. The analysis of numerous overlapping satellite images revealed an abundant volume of 4400 m3 of oil naturally reaching the sea surface per year, expelled from more than a hundred seep sites through the Lower Congo Basin. The active seepage area is located in the distal compressional province of the basin where salt napes and squeezed diapirs. The integration of current data was used to link accurately sea surface manifestations of natural oil leakages with active fluid flow features on the seafloor. A mooring with ADCPs (Acoustic Doppler Current Profilers) distributed throughout the water column provided an efficient calibration tool to evaluate the horizontal deflection of oil droplets. Using a Eulerian propagation model that considered a range of probable ascent speeds, we estimated the oil migration pathways through the water column using two different approaches. The first approach consisted in simulating the backwards trajectory of oil droplets using sea surface oil slicks locations and concomitant current measurements. The second method analyzed the spatial spreading of the surfacing signatures of natural oil slicks based on 21 years of satellite observations. The location of the surfacing points of oil droplets at the sea surface is restricted to a circle of 2.5 km radius around the release point at the seafloor. Both approaches provided a range of ascent speeds of oil droplets between 3 to 8 cm.s-1. The low deflection values validate the near-vertical links between the average surfacing area of oil slicks at the sea surface with specific seafloor disturbances (i.e. pockmarks or mounds) known to expel fluids.

Organic matter diagenesis within the water column and surface sediments of the northern Sargasso Sea revealed by lipid biomarkers

NASA Astrophysics Data System (ADS)

Conte, M. H.; Pedrosa Pàmies, R.; Weber, J.

2017-12-01

The intensity of particle cycling processes within the mesopelagic and bathypelagic ocean controls the length scale of organic material (OM) remineralization and diagenetic transformations of OM composition through the water column and into the sediments. To elucidate the OM cycling in the oligotrophic North Atlantic gyre, we analyzed lipid biomarkers in the suspended particles (30-4400 m depth, 100 mab), the particle flux (500 m, 1500 m and 3200 m depth), and in the underlying surficial sediments (0-0.5 cm, 4500-4600 m depth) collected at the Oceanic Flux Program (OFP) time series site located 75km SE of Bermuda. Changes in lipid biomarker concentration and composition with depth highlight the rapid remineralization of OM within the upper mesopelagic layer and continuing diagenetic transformations of OM throughout the water column and within surficial sediments. Despite observed similarities in biomarker composition in suspended and sinking particles, results show there are also consistent differences in relative contributions of phytoplankton-, bacterial- and zooplankton-derived sources that are maintained throughout the water column. For example, sinking particles are more depleted in labile biomarkers (e.g. polyunsaturated fatty acids (PUFA)) and more enriched in bacteria-derived biomarkers (e.g. hopanoids and odd/branched fatty acids) and indicators of fecal-derived OM (e.g. saturated fatty acids, FA 18:1w9 and cholesterol) than in the suspended pool. Strong seasonality in deep (3200 m) fluxes of phytoplankton-derived biomarkers reflect the seasonal input of bloom-derived material to underlying sediments. The rapid diagenetic alteration of this bloom-derived input is evidenced by depletion of PUFAs and enrichment of microbial biomarkers (e.g. odd/branched fatty acids) in surficial sediments over a two month period.

Enhanced capabilities of separation in Sequential Injection Chromatography--fused-core particle column and its comparison with narrow-bore monolithic column.

PubMed

Chocholouš, Petr; Kosařová, Lucie; Satínský, Dalibor; Sklenářová, Hana; Solich, Petr

2011-08-15

In the Sequential Injection Chromatography (SIC) only monolithic columns for chromatographic separations have been used so far. This article presents the first use of fused-core particle packed column in an attempt to extend of the chromatographic capabilities of the SIC system. A new fused-core particle column (2.7 μm) Ascentis(®) Express C18 (Supelco™ Analytical) 30 mm × 4.6 mm brings high separation efficiency within flow rates and pressures comparable to monolithic column Chromolith(®) Performance RP-18e 100-3 (Merck(®)) 100 mm × 3 mm. Both columns matches the conditions of the commercially produced SIC system - SIChrom™ (8-port high-pressure selection valve and medium-pressure Sapphire™ syringe pump with 4 mL reservoir - maximal work pressure 1000 PSI) (FIAlab(®), USA). The system was tested by the separation of four estrogens with similar structure and an internal standard - ethylparaben. The mobile phase composed of acetonitrile/water (40/60 (v/v)) was pumped isocratic at flow rate 0.48 mL min(-1). Spectrophotometric detection was performed at wavelength of 225 nm and injected volume of sample solutions was 10 μL. The chromatographic characteristics of both columns were compared. Obtained results and conclusions have shown that both fused-core particle column and longer narrow shaped monolithic column bring benefits into the SIC method. Copyright © 2011 Elsevier B.V. All rights reserved.

Distribution, diffusive fluxes, and toxicity of heavy metals and PAHs in pore water profiles from the northern bays of Taihu Lake.

PubMed

Lei, Pei; Zhang, Hong; Shan, Baoqing; Zhang, Bozheng

2016-11-01

Pore water plays a more significant role than do sediments in pollutant cycling dynamics. Also, concentrations of pollutants in pore water provide important information about their bioavailability or eco-toxicity; however, very few studies have focused on this topic. In this study, four duplicate sediment cores from three typical northern bays as well as the central part of Taihu Lake were collected to investigate the distribution, diffusive fluxes, and toxicity of heavy metals and polycyclic aromatic hydrocarbons (PAHs) in pore water profiles, which will be good in understanding the mobility and toxicity of these toxic pollutants and achieving better environmental management. The diffusive fluxes of heavy metals across the sediment-water interface was estimated through Fick's First Law, and the toxicity of heavy metals and PAHs in pore water was assessed by applying a water quality index (interstitial water toxicity criteria unit, IWCTU) and a hazard index (HI), respectively. The average concentrations of Cr, Cu, Ni, Pb, and Zn in surface pore water were 18.8, 23.4, 12.0, 13.5, and 42.5 μg L -1 , respectively. Also, concentrations of the selected heavy metals in both overlying water and pore water from Taihu Lake were all lower than the standard values of the environmental quality standards for surface water. The concentrations as the pore water depth increased, and the highest detected concentrations of heavy metals were recorded between 3 and 5 cm below the sediment surface. The average diffusive fluxes of these metals were 27.3, 24.8, 7.03, 7.81, and -3.32 μg (m 2 day) -1 , respectively, indicating export from sediment into overlying water, with the exception of Zn. There was a potential risk of toxicity, mainly from Pb and Cu, indicating that heavy metals in pore water had slight to moderate impact on sediment-dwelling organisms by values of the IWCTU and the Nemeraw index. The total PAH concentrations in pore water were higher than those in overlying

Natural and anthropogenic hydrocarbons in the water column of the Ross Sea (Antarctica)

NASA Astrophysics Data System (ADS)

Cincinelli, Alessandra; Martellini, Tania; Bittoni, Lucilla; Russo, Aniello; Gambaro, Andrea; Lepri, Luciano

2008-09-01

In the framework of the Italian Research Programme in Antarctica (PNRA) an oceanographic cruise was carried out between December 2000 and February 2001 in the Western Ross Sea. n-Alkanes and PAHs concentrations were analysed in sea-water samples collected at different depths at four sites (D, B, CA2, and CA). Vertical profiles of pressure, temperature, salinity and fluorescence were also performed in order to distinguish the water masses present in the sampling areas. n-Alkanes concentrations were consistent with those found in the same area during previous expeditions and showed higher values in the particulate due to the low temperatures. n-Alkanes profiles exhibited different features in the dissolved and particulate phases. The dissolved phase was characterised by a bimodal distribution with two maxima at C16 and C24 and prevalent compounds in the range C15-C32 whereas particulate was strongly dominated by long chain n-alkanes C23-C34 with C24 (Site B, CA and CA2) or C32 (Site B) as Cmax. CPI values and Pr/Ph ratios suggested a prevalent biogenic origin for aliphatic hydrocarbons. n-Alkanes vertical distributions were affected by the dynamic of the pack-ice melting and phytoplankton activity as well by the chemical-physical properties of water masses. Higher n-alkanes values were found in the High Salinity Shelf Waters (HSSW), lower n-alkanes values were found in the Antarctic Surface Waters (AASW) and Modified Circumpolar Deep Water (MCDW). The low PAHs concentration levels confirmed the still pristine character of the Antarctic environment. Neither particular trend in total PAHs concentrations along the water column and nor correlations with the most characteristic water masses of the investigated area of the Ross Sea were observed, except that total PAH higher concentrations were generally observed in correspondence of HSSW.

ssDNA aptamer-based column for simultaneous removal of nanogram per liter level of illicit and analgesic pharmaceuticals in drinking water.

PubMed

Hu, Xiangang; Mu, Li; Zhou, Qixing; Wen, Jianping; Pawliszyn, Janusz

2011-06-01

Aptamers are a new class of single-stranded DNA/RNA molecules selected from synthetic nucleic acid libraries for molecular recognition. Our group reports a novel aptamer column for the removal of trace (ng/L) pharmaceuticals in drinking water. In this study, cocaine and diclofenac were chosen as model molecules to test the aptamer column which presented high removal capacity, selectivity, and stability. The removal of pharmaceuticals was as high as 88-95%. The data of adsorption were fitted with Langmuir isotherm and a pseudo-second-order kinetic model. A thermodynamic experiment proved the adsorption processes were exothermic in spontaneity. The kinetics of aptamer was composed of three steps: activation, binding, and hybridization. The first step was the rate-controlling step. The adsorption system was divided into three parts: kinetic, mixed, and thermodynamic zones from 0% to 100% binding fraction of aptamer. Furthermore, the aptamer column was reusable and achieved strong removal efficiency from 4 to 30 °C at normal cation ion concentration (5-100 mg/L) for multipollutants without cross effects and secondary pollution. This work indicates that aptamer, as a new sorbent, can be used in the removal of persistent organic pollutants, biological toxins, and pathogenic bacteria from surface, drinking, and ground water.

Ideal versus real automated twin column recycling chromatography process.

PubMed

Gritti, Fabrice; Leal, Mike; McDonald, Thomas; Gilar, Martin

2017-07-28

The full baseline separation of two compounds (selectivity factors α<1.03) is either impractical (too long analysis times) or even impossible when using a single column of any length given the pressure limitations of current LC instruments. The maximum efficiency is that of an infinitely long column operated at infinitely small flow rates. It is determined by the maximum allowable system pressure, the column permeability (particle size), the viscosity of the eluent, and the intensity of the effective diffusivity of the analytes along the column. Alternatively, the twin-column recycling separation process (TCRSP) can overcome the efficiency limit of the single-column approach. In the TCRSP, the sample mixture may be transferred from one to a second (twin) column until its band has spread over one column length. Basic theory of chromatography is used to confirm that the speed-resolution performance of the TCRSP is intrinsically superior to that of the single-column process. This advantage is illustrated in this work by developing an automated TCRSP for the challenging separation of two polycyclic aromatic hydrocarbon (PAH) isomers (benzo[a]anthracene and chrysene) in the reversed-phase retention mode at pressure smaller than 5000psi. The columns used are the 3.0mm×150mm column packed with 3.5μm XBridge BEH-C 18 material (α=1.010) and the 3.0mm or 4.6mm×150mm columns packed with the same 3.5μm XSelect HSST 3 material (α=1.025). The isocratic mobile phase is an acetonitrile-water mixture (80/20, v/v). Remarkably, significant differences are observed between the predicted retention times and efficiencies of the ideal TCRSP (given by the number of cycles multiplied by the retention time and efficiency of one column) and those of the real TCRSP. The fundamental explanation lies in the pressure-dependent retention of these PAHs or in the change of their partial molar volume as they are transferred from the mobile to the stationary phase. A revisited retention and

Effects of water chemistry and surface contact on the toxicity of silver nanoparticles to Bacillus subtilis.

PubMed

Yi, Jun; Cheng, Jinping

2017-07-01

The growing use of silver nanoparticles (AgNPs) has created concerns about its potential impacts on natural microbial communities. In this study, the physicochemical properties of AgNPs and its toxicity on natural bacteria Bacillus subtilis (B. subtilis) were investigated in aqueous conditions. The characterization data showed that AgNPs highly aggregated in aqueous conditions, and the hydrodynamic diameter of AgNPs in aqueous conditions was larger than its primary size. The studied AgNPs was less toxic to B. subtilis in estuarine water as compared to that in Milli-Q water and artificial seawater, which might be due to the observed enhanced aggregation of AgNPs in estuarine water. The toxicity of AgNPs to B. subtilis was greatly reduced when their surface contact was blocked by a dialysis membrane. Scanning electron microscope images showed that exposure contact to AgNPs resulted in damage of the microbial cell wall and enhanced formation of fibrillar structures. These results suggest that particle-cell contact is largely responsible for the observed toxicity of AgNPs in B. subtilis. This study can help to understand the potential impacts of AgNPs to natural microbes, especially in the complex aquatic environments.

Trophic State and Toxic Cyanobacteria Density in Optimization Modeling of Multi-Reservoir Water Resource Systems

PubMed Central

Sulis, Andrea; Buscarinu, Paola; Soru, Oriana; Sechi, Giovanni M.

2014-01-01

The definition of a synthetic index for classifying the quality of water bodies is a key aspect in integrated planning and management of water resource systems. In previous works [1,2], a water system optimization modeling approach that requires a single quality index for stored water in reservoirs has been applied to a complex multi-reservoir system. Considering the same modeling field, this paper presents an improved quality index estimated both on the basis of the overall trophic state of the water body and on the basis of the density values of the most potentially toxic Cyanobacteria. The implementation of the index into the optimization model makes it possible to reproduce the conditions limiting water use due to excessive nutrient enrichment in the water body and to the health hazard linked to toxic blooms. The analysis of an extended limnological database (1996–2012) in four reservoirs of the Flumendosa-Campidano system (Sardinia, Italy) provides useful insights into the strengths and limitations of the proposed synthetic index. PMID:24759172

Immunoaffinity column as clean-up tool for determination of trace amounts of microcystins in tap water.

PubMed

Tsutsumi, T; Nagata, S; Hasegawa, A; Ueno, Y

2000-07-01

Trace amounts of microcystins (MCs) in drinking water should be monitored because of their potential hazard for human health as an environmental tumor promoter. We describe here a new clean-up tool with immunoaffinity column (IAC) for determination of trace amounts of MCs (from pg to microg/litre) in tap water. The water samples were concentrated with IAC clean-up and MCs levels were determined by HPLC with UV detection or enzyme-linked immunosorbent assay (ELISA). In the combination with HPLC analysis, mean recovery of microcystin-LR (MCLR),-RR and-YR spiked to tap water were 91.8%, 77.3% and 86.4%, respectively, in the range 2.5-100 microg/litre. The chromatogram of MCs-spiked tap water sample cleaned up with IAC showed effective elimination of the impurities compared to that with octadecyl silanized cartridge, which had been cleaned up with a conventional method. Also, in the combination with highly sensitive ELISA, mean recovery of MCLR spiked to tap water was 80% in the range 0.1-1000 ng/litre. The combined methods developed here can detect pg to microg/litre of MCs in tap water. The overall results indicated that IAC will be suitable as a clean-up tool for trace amounts of MCs in tap water.

The effect of feed water dissolved organic carbon concentration and composition on organic micropollutant removal and microbial diversity in soil columns simulating river bank filtration.

PubMed

Bertelkamp, C; van der Hoek, J P; Schoutteten, K; Hulpiau, L; Vanhaecke, L; Vanden Bussche, J; Cabo, A J; Callewaert, C; Boon, N; Löwenberg, J; Singhal, N; Verliefde, A R D

2016-02-01

This study investigated organic micropollutant (OMP) biodegradation rates in laboratory-scale soil columns simulating river bank filtration (RBF) processes. The dosed OMP mixture consisted of 11 pharmaceuticals, 6 herbicides, 2 insecticides and 1 solvent. Columns were filled with soil from a RBF site and were fed with four different organic carbon fractions (hydrophilic, hydrophobic, transphilic and river water organic matter (RWOM)). Additionally, the effect of a short-term OMP/dissolved organic carbon (DOC) shock-load (e.g. quadrupling the OMP concentrations and doubling the DOC concentration) on OMP biodegradation rates was investigated to assess the resilience of RBF systems. The results obtained in this study imply that - in contrast to what is observed for managed aquifer recharge systems operating on wastewater effluent - OMP biodegradation rates are not affected by the type of organic carbon fraction fed to the soil column, in case of stable operation. No effect of a short-term DOC shock-load on OMP biodegradation rates between the different organic carbon fractions was observed. This means that the RBF site simulated in this study is resilient towards transient higher DOC concentrations in the river water. However, a temporary OMP shock-load affected OMP biodegradation rates observed for the columns fed with the river water organic matter (RWOM) and the hydrophilic fraction of the river water organic matter. These different biodegradation rates did not correlate with any of the parameters investigated in this study (cellular adenosine triphosphate (cATP), DOC removal, specific ultraviolet absorbance (SUVA), richness/evenness of the soil microbial population or OMP category (hydrophobicity/charge). Copyright © 2015 Elsevier Ltd. All rights reserved.

Water quality and aquatic toxicity data of 2002 spring thaw conditions in the upper Animas River watershed, Silverton, Colorado

USGS Publications Warehouse

Fey, D.L.; Wirt, L.; Besser, J.M.; Wright, W.G.

2002-01-01

This report presents hydrologic, water-quality, and biologic toxicity data collected during the annual spring thaw of 2002 in the upper Animas River watershed near Silverton, Colorado. The spring-thaw runoff is a concern because elevated concentrations of iron oxyhydroxides can contain sorbed trace metals that are potentially toxic to aquatic life. Water chemistry of streams draining the San Juan Mountains is affected by natural acid drainage and weathering of hydrothermal altered volcanic rocks and by more than a century of mining activities. The timing of the spring-thaw sampling effort was determined by reviewing historical climate and stream-flow hydrographs and current weather conditions. Twenty-one water-quality samples were collected between 11:00 AM March 27, 2002 and 6:00 PM March 30, 2002 to characterize water chemistry at the A-72 gage on the upper Animas River below Silverton. Analyses of unfiltered water at the A-72 gage showed a relation between turbidity and total-recoverable iron concentrations, and showed diurnal patterns. Copper and lead concentrations were related to iron concentrations, indicating that these elements are probably sorbed to colloidal iron material. Calcium, strontium, and sulfate concentrations showed overall decreasing trends due to dilution, but the loads of those constituents increased over the sampling period. Nine water-quality samples were collected near the confluence of Mineral Creek with the Animas River, the confluence of Cement Creek with the Animas River, and on the upper Animas River above the confluence with Cement Creek (three samples at each site). A total of six bulk water-toxicity samples were collected before, during, and after the spring thaw from the Animas River at the A-72 gage site. Toxicity tests conducted with the bulk water samples on amphipods did not show strong differences in toxicity among the three sampling periods; however, toxicity of river water to fathead minnows showed a decreasing trend