Mass Balance

During the last glacial-interglacial cycle, northern hemispheric (NH) ice-sheets experienced dramatic changes in radiative forcing, due to orbitally-driven insolation changes and varying greenhouse gas concentrations. This direct forcing caused temperature changes and eventually ablation anomalies. Orbital-scale variations in the atmospheric circulation caused anomalies in temperature advection and precipitation/snowfall that also strongly contributed to the mass balance and hence the time-evolution

In small-scale mining in northeastern Brazil, the exploitation of industrial minerals, where kaolin bearing pegmatites are mined, is common. The mineral processing of kaolin is based in mixer and classification by screen and cyclone. The overflow of cyclone is thickened and filtered by pressure filter. The product is dried for market. This work presents the results of tailings characterization. Mass balance was realized and recuperation of kaolin about 56% was identified. The feed grade of Al 2 O 3 in the plant is 21.20%. The kaolin product for market sold by the company presents 37.19% Al 2 O 3 and whiteness of 81.9%. The average Al 2 O 3 content of the tailing is 15.55%. Minerals identified are feldspar, muscovite, tourmaline, illite and kaolinite. The À325# fraction of the tailings present Al 2 O 3 grades with characteristics for market (Al 2 O 3-35%) and whiteness of 79.7%. Values from 7 to 34 wt% of this À325# fraction were determined in the tailing samples analyzed; these results validate the feasibility of reprocessing the tailings for using in the ceramic industry.

Molybdenum (Mo) isotope studies in black shales can provide information about the redox evolution of the Earth's oceans, provided the isotopic consequences of Mo burial into its major sinks are well understood. Previous applications of the Mo isotope paleo-ocean redox proxy assumed quantitative scavenging of Mo when buried into sulfidic sediments. This paper contains the first complete suite of Mo isotope fractionation observations in a sulfidic water column and sediment system, the meromictic Lake Cadagno, Switzerland, a small alpine lake with a pronounced oxygen-sulfide transition reaching up to H 2 S $ 200 lM in the bottom waters (or about 300 lM total sulfide: RS 2À = H 2 S + HS À + S 2À ). We find that Mo behaves conservatively in the oxic zone and non-conservatively in the sulfidic zone, where dissolved Mo concentrations decrease from 14 nM to 2-8 nM across this transition. Dissolved Mo in the upper oxic waters has a d 98 Mo oxic = 0.9 ± 0.1&, which matches that of the riverine input, d 98 Mo river = 0.9 ± 0.1&. In the deeper sulfidic waters, a subaquatic source delivers Mo at 1.55 ± 0.1&, but the dissolved Mo is even heavier at d 98 Mo sulfidic = 1.8&. Sediment traps in the sulfidic zone of the lake collect particles increasingly enriched in Mo with depth, with d 98 Mo values significantly fractionated at À0.8& to À1.2& both near the chemocline and in the deepest trap. Suspended particulates in the sulfidic waters carry lighter Mo than the ambient dissolved Mo pool by $0.3-1.5&. Sedimentary Mo concentrations correlate with total organic carbon and yield Mo levels which are two orders of magnitude higher than typical crustal values found in rocks from the catchment area. Solid-phase Mo in the sediment shows a slightly positive d 98 Mo trend with depth, from d 98 Mo = 1.2& to 1.4& while the pore waters show dramatic enrichments of Mo (>2000 nM) with a relatively light isotope signature of d 98 Mo = 0.9-1.0&.

The UNMIX and Chemical Mass Balance (CMB) receptor models were used to investigate sources of PM 2.5 aerosols measured between March 2001 and February 2002 in Gwangju, Korea. Measurements of PM 2.5 particles were used for the analysis of carbonaceous species (organic (OC) and elemental carbon (EC)) using the thermal manganese dioxide oxidation (TMO) method, the investigation of seven ionic species using ion chromatography (IC), and the analysis of twenty-four metal species using Inductively Coupled Plasma (ICP)-Atomic Emission Spectrometry (AES)/ICP-Mass Spectrometry (MS). According to annual average PM 2.5 source apportionment results obtained from CMB calculations, diesel vehicle exhaust was the major contributor, accounting for 33.4% of the measured PM 2.5 mass (21.5 μg m − 3), followed by secondary sulfate (14.6%), meat cooking (11.7%), secondary organic carbon (8.9%), secondary nitrate (7.6%), urban dust (5.5%), Asian dust (4.4%), biomass burning (2.8%), sea salt (2.7%), residual oil combustion (2.6%), gasoline vehicle exhaust (1.9%), automobile lead (0.5%), and components of unknown sources (3.4%). Seven PM 2.5 sources including diesel vehicles (29.6%), secondary sulfate (17.4%), biomass burning (14.7%), secondary nitrate (12.6%), gasoline vehicles (12.4%), secondary organic carbon (5.8%) and Asian dust (1.9%) were identified from the UNMIX analysis. The annual average source apportionment results from the two models are compared and the reasons for differences are qualitatively discussed for better understanding of PM 2.5 sources. Additionally, the impact of air mass pathways on the PM 2.5 mass was evaluated using air mass trajectories calculated with the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) backward trajectory model. Source contributions to PM 2.5 collected during the four air mass patterns and two event periods were calculated with the CMB model and analyzed. Results of source apportionment revealed that the contribution of diesel traffic exhaust (47.0%) in stagnant conditions (S) was much higher than the average contribution of diesel vehicle exhaust (33.4%) during the sampling period. During Asian dust (AD) periods when the air mass passed over the Korean peninsula, Asian dust and secondary organic carbon accounted for 25.2 and 23.0% of the PM 2.5 mass, respectively, whereas Asian dust contributed only 10.8% to the PM 2.5 mass during the AD event when the air mass passed over the Yellow Sea. The contribution of biomass burning to the PM 2.5 mass during the biomass burning (BB) event equaled 63.8%.

A simple climate model has been developed to investigate the existence of the small ice cap instability in the Southern Hemisphere. The model consists of four coupled components: an atmospheric energy balance model, a thermodynamic snow-sea ice model, an oceanic mixed layer model and a terrestrial ice model. Results from a series of experiments involving different degrees of coupling in the model show that the instability appears only in those cases when an explicit representation of the Antarctic ice sheet is not included in the model. In order to determine which physical processes in the ice sheet model lead to a stabilization of the system we have conducted several sensitivity experiments in each of which a given ice sheet process has been removed from the control formulation of the model. Results from these experiments suggest that the feedback between the elevation of the ice sheet and the snow accumulation-ice ablation balance is responsible for the disappearance of the small ice cap instability in our simulation. In the model, the mass balance of the ice sheet depends on the air temperature at sea level corrected for altitude and it is, therefore, a function of surface elevation. This altitudemass balance feedback effectively decouples the location of the ice edge from any specific sea level isotherm, thus decreasing the model sensitivity to the albedotemperature feedback, which is responsible for the appearance of the instability. It is also shown that M. A. Morales Maqueda ()) A

The fate of black carbon deposited on the soil surface after burning of harvesting residues is poorly understood. In this study we quantified horizontal as well as vertical transport of total pyrogenic carbon and its chemically most stable part (OREC) during a rainfall experiment after an experimental burn. The aim of the study was to assess the importance of splash erosion versus runoff for the export of total pyrogenic carbon and OREC from soil. Our methodological approach included the comparison of 1 m 2 plots with splash erosion to 1 m 2 plots where splash erosion was prevented by mosquito nets. On these plots, we quantified total pyrogenic carbon and OREC in the soil before and after the rainfall simulation. Additionally, we assessed the amount of total pyrogenic C and OREC exported from the plots and transported vertically into the soil. Our results showed that 7-55% of pyrogenic carbon was subject to horizontal and another 23-46% of initial deposited pyrogenic C subject to vertical transport. The export of total pyrogenic carbon and OREC at least doubled on plots where splash was allowed. OREC was less prone to vertical transport than total pyrogenic C. We explained the contrasting observation for both carbon types by the favourable floating behaviour of OREC compared to higher sedimentation rates of other pyrogenic C types, which may partly lead to redistribution of the latter. The presence or absence of splash erosion was found to determine the magnitude of horizontal versus vertical transport and thereby the fate of black C in soil.

1] We present a new statistical method to construct a model for the chemical composition of Earth's primitive mantle along with its variance. Earth's primitive mantle is located on the melting trend exhibited by the global compilation of mantle peridotites, using cosmochemical constraints on the relative abundances of refractory lithophile elements (RLE). This so-called pyrolite approach involves the least amount of assumptions, thereby being probably most satisfactory compared to other approaches. Its previous implementations, however, suffer from questionable statistical treatment of noisy geochemical data, leaving the uncertainty of model composition poorly quantified. In order to properly take into account how scatters in peridotite data affect this geochemical inference, we combine the following statistical techniques: (1) modeling a nonlinear melting trend in the multidimensional compositional space through the principal component analysis, (2) determining the primitive mantle composition on the melting trend by simultaneously imposing all of cosmochemical constraints with least squares, and (3) mapping scatters in original data into the variance of the final model through the bootstrap resampling technique. Whereas our model is similar to previous models in terms of Mg, Si, and Fe abundances, the RLE contents are at $2.16 ± 0.37 times the CI chondrite concentration, which is lower than most of previous estimates. The new model is depleted by >20% in a number of incompatible elements including heat-producing elements, U, Th, and K, and this depleted nature is further amplified (up to 60%) in terms of predicted composition for the present-day mantle.

We introduce a discrete fracture network model of stationary Darcy flow in fractured rocks. We approximate the fractures by a network of planar circle disks, which is generated on the basis of statistical data obtained from field measurements. We then discretize this network into a mesh consisting of triangular elements placed in three-dimensional space. We use geometrical approximations in fracture planes, which allow for a significant simplification of the final triangular meshes. We consider two-dimensional Darcy flow in each fracture. In order to accurately simulate the channeling effect, we assign to each triangle an aperture defining its hydraulic permeability. For the discretization we use the lowest order Raviart-Thomas mixed finite element method. This method gives quite an accurate velocity field, which is computed directly and which satisfies the mass balance on each triangular element. We demonstrate the use of this method on a model problem with a known analytical solution and describe the generation and triangulation of the fracture network and the computation of fracture flow for a particular real situation.

Solute transport rates within the uppermost 2 cm of a rippled continental shelf sand deposit, with a mean grain size of 400-500 mm and permeabilities of 2.0-2.4 Â 10 À11 m 2 , have been measured in situ by detecting the breakthrough of a pulse of iodide after its injection into the bottom water. These tracer experiments were conducted on the USA Middle Atlantic Bight shelf at a water depth of B13 m using a small tethered tripod that carried a close-up video camera, acoustic current meter, motorized 1.5 liter ''syringe'', and a microprofiling system for positioning and operating a solidstate voltammetric microelectrode. When triggered on shipboard, the syringe delivered a 0.21 M solution of potassium iodide and red dye through five nozzles positioned around and above the buried tip of the voltammetric sensor for 0.65-5 min. Bottom turbulence rapidly mixed and dispersed the tracer, which then was carried into the bed by interfacial water flows associated with ripple topography. The advective downward transport to the sensor tip was timed by a sequence of repetitive voltammetric scans. The distance-averaged vertical velocity, expressed as the depth of the sensor tip in the sand divided by the time to iodide breakthrough, was found to vary from 6 to 53 cm h À1 and generally to decrease with sediment depth. Because of episodic pumping and dispersion associated with the greatest 5% of wave heights and current speeds recorded, some concentration vs. time responses showed evidence of uneven solute migration. For reasons of mass balance, the advective flow field in the surface layers of permeable beds includes regions of water intrusion, horizontal pore-water flow and upwelling which also may explain some of the observed uneven migration. Pore-water advection was also evident in oxygen profiles measured before and after tracer injection with the voltammetric sensor. These profiles showed irregular distributions and oxygen penetration depths of 4-4.5 cm.

The transient response to projected climate change of two ice caps in the central Icelandic highland was simulated with a vertically integrated ice-flow model coupled to a degree-day mass-balance model. The ice caps, Langjökull and Hofsjökull, are of similar size (area ∼900 km2 and volume ∼200 km3) and located only ∼30 km apart. The climate change simulations were started in 1990 from steady states corresponding to the average climate of 1981–2000 and driven with observed weather parameters until 2005. Thereafter, the forcing was according to a Nordic climate change scenario based on the IPCC B2 emission scenario. The simulations during the period 1990–2005 compare reasonably well with observations of mass-balance and glacier extent. Both ice caps are projected to essentially disappear during the next 100 to 200 years. Langjökull, which disappears within the next 150 years, shows larger mass-balance sensitivity to warming than the higher elevated Hofsjökull, where ice on the highest...

This paper is the first part of a twofold contribution dedicated to the new version of the Louvain-la-Neuve sea ice model LIM3. In this part, LIM3 is described and its results are compared with observations. LIM3 is a C-grid dynamic-thermodynamic model, including the representation of the subgrid-scale distributions of ice thickness, enthalpy, salinity and age. Brine entrapment and drainage as well as brine impact on ice thermodynamics are explicitly included. LIM3 is embedded into the ocean modelling system NEMO, using OPA9, a hydrostatic, primitive equation, finite difference ocean model in the 2°Â 2°cos/ configuration ORCA2. Model performance is evaluated by performing a hindcast of the Arctic and Antarctic sea ice packs, forced by a combination of daily NCEP/NCAR reanalysis data and various climatologies. The annual cycle of sea ice growth and decay is very realistically captured with ice area, thickness, drift and snow depth in good agreement with observations. In the Arctic, the simulated geographical distributions of ice thickness and concentration are significantly improved when compared with earlier versions of LIM. Model deficiencies feature an overestimation (underestimation) of ice thickness in the Beaufort gyre (around the North Pole) as well as an underestimation of ice thickness in the Southern Ocean. The simulated first year/multiyear sea ice limit agrees with observations. The values and distribution of sea ice age in the perennial ice zone are different from satellite-derived values, which is attributed to the different definitions of ice age. In conclusion, in light of the exhaustive sea ice analysis presented here, LIM3 is found to be an appropriate tool for large-scale sea ice and climate simulations.

Detailed d13C stratigraphies have been published recently for several Cenomanian-Turonian pelagic sections of southern England, and the Lower Saxony basin of Germany. The observed changes in the d13C record provide a useful tool for high-resolution stratigraphic correlation, and are used here to create a composite Cenomanian-Turonian d13C curve in a time-related framework. A best fit curve to 673 carbon isotope data is provided using the LOWESS regression scatterplot smoother. The long-term trend of the smoothed composite d13C profile varies on time scales of 106 years, and shows stable d13C values through the Lower Cenomanian, an increase in the Middle and Upper Cenomanian, with a major positive excursion around the Cenomanian-Turonian boundary, and a decrease through the Lower and Middle Turonian. Short-term fluctuations vary on time scales of 105 years, and dominated the d13C signal in the higher Middle and Upper Turonian. Changes of the Cenomanian-Turonian d13C record have commonly been explained by variations in the organic carbon flux to the sedimentary reservoir, in response to eustatic sea-level change. However, mass balance consideration suggests also an influence of carbonate production and burial rate on the d13C signal. Enhanced inorganic carbon burial increased the ratio of the inorganic to organic carbon fluxes and shifted the 13C/12C ratio to more negative values. This pattern may be observed in the Early and Middle Turonian d13C long-term record, and correlates with the spatial expansion of pelagic carbonate deposits in epicontinental seas. Short-term d13C variations could be either a directly response to short-term sea-level changes, reflecting local conditions in the European epicontinental sea, or could represent changes in oceanic 12C storage in response to the varying intensity of thermohaline circulation.

Pesticides are currently used inside hives, against the honeybee parasite Varroa destructor, producing unwanted contamination effects. To assess the distribution and fate of one of these pesticides (coumaphos), two experimental hives were treated with Perizin (the commercial product containing the active ingredient coumaphos). Samples of honey, wax, pollen, adult bees and larvae taken before treatment and up to 104 days afterwards, showed diffuse contamination. Wood hedges and wax bridges, where the pesticide solution was applied, were analysed as well. A mass balance was calculated, yielding a recovered amount of around 60% just after treatment and 38% 1 month later. Directly contaminated surfaces and wax contained the highest amount of residues. Wax and honey contained different amounts (10, and 0.1% respectively) but both retained residues for long time. Bees ingest most of the product just after treatment, then rapidly eliminate it by metabolism, advection and deposition processes. On the basis of analytical results, a simple model (level I of the fugacity model) was applied to the hive system for different pesticides (coumaphos, malathion, fluvalinate and bromopropylate). Predicted concentrations in wax and honey were compared with those measured, indicating the good predictive capability of this approach.

A regional atmospheric model, the HIRHAM4 regional climate model (RCM) using boundary conditions from the ECHAM5 atmosphere-ocean general circulation model (AOGCM), was downscaled to a 500-m gridcell increment using SnowModel to simulate 131 yr of hydrologic cycle evolution in west Greenland's Kangerlussuaq drainage. Projected changes in the Greenland Ice Sheet (GrIS) surface mass balance (SMB) and runoff are relevant for potential hydropower production and prediction of ecosystem changes in sensitive Kangerlussuaq Fjord systems. Mean annual surface air temperatures and precipitation in the Kangerlussuaq area were simulated to increase by 3.48C and 95 mm water equivalent (w.eq.), respectively, between 1950 and 2080. The local Kangerlussuaq warming was less than the average warming of 4.88C simulated for the entire GrIS. The Kangerlussuaq SMB loss increased by an average of 0.3 km 3 because of a 0.4 km 3 rise in precipitation, 0.1 km 3 rise in evaporation and sublimation, and 0.6 km 3 gain in runoff . By 2080, the spring runoff season begins approximately three weeks earlier. The average modeled SMB and runoff is approximately 20.1 and 1.2 km 3 yr 21 , respectively, indicating that ;10% of the Kangerlussuaq runoff is explained by the GrIS SMB net loss. The cumulative net volume loss from SMB was 15.9 km 3 , and runoff was 151.2 km 3 w.eq. This runoff volume is expected to have important hydrodynamic and ecological impacts on the stratified salinity in the Kangerlussuaq Fjord and on the transport of freshwater to the ocean.

A prerequisite for the calculation of the proportion of a legume’s nitrogen derived from the atmosphere (%Ndfa) using the 15N natural abundance technique (NA) is the determination of the B value (δ15N value for a legume when completely dependent on N2 fixation for growth). With this objective, Kabuli-type chickpea seeds were inoculated with Mesorhizobium ciceri, strain ISC-6, and an indigenous strain mixture (ISM) from the Guadalquivir Valley (southern Spain); and mayor-equina-type faba bean seeds were inoculated with Rhizobium leguminosarum strain ISL-19. Both legumes were grown in perlite with an N-free nutrient solution and in a growth chamber; uninoculated plants were also grown under the same conditions. Samples of the inoculated plants were collected at full flowering and maturity, analyzing total N and 15N content of the nodules, root, shoot and seeds. The seeds sown and uninoculated plants at wilting were also analyzed. The uninoculated chickpea and faba bean plants showed strong 15N discrimination in the remobilization of reserve proteins from the cotyledons to the shoot. Only 52% of the 15N from the chickpea seed and 46% from the faba bean seed were translocated to the shoot. The Bwhole plant value for both inoculated species (−1.44‰ in chickpea and −1.33‰ in faba bean) demonstrated the existence of a significant isotopic discrimination of N in the fixation of atmospheric N2. The Bshoot value did not show significant differences between full flowering and seed maturity for either species, which allowed field sampling to be performed for the calculation of %Ndfa between both growth stages. Each species presented different 15N discrimination for the different parts analyzed. In chickpea, strong discrimination was observed between the nodules (+3.11‰) and the rest of the plant (−1.67‰); this discrimination was less pronounced in faba bean and always with negative values between the underground parts (nodules and root, with a mean value of −0.75‰) and the shoot (−1.71‰). The Bshoot value obtained was −1.80‰ in chickpea and −1.71‰ in faba bean. However, given the importance of the amount of seed N in chickpea and faba bean, seed 15N contribution should be considered in the calculation of the Bshoot value using a mass balance model which considers 50% of this amount. In this case, the adjusted Bshoot values would increase to −2.05‰ and −1.89‰ in chickpea and faba bean, respectively.

A system to turn a potentially harmful stream of solid waste into a set of substreams with either commercial value or highly concentrated residual streams is presented. The waste which is considered is metal impregnated (in particular Chromated Copper Arsenate (CCA) treated) wood waste and timber, such as telephone poles, railway sleepers, timber from landscape and cooling towers, wooden silos, hop-poles, cable drums and wooden playground equipment. These waste streams sum up to several 100,000 tons of material per year currently to be dumped in every major country of the European Community (EC).

Application of cosmogenic radionuclide 22 Na to limnological research was first successfully performed in the Lake Biwa system, Japan. The 22 Na was determined from large water samples of more than 500 L by using the ultra low-background Gedetector installed at underground (Ogoya Lab.) after simple chemical separation. Extremely low 22 Na concentrations ranging from 19.9 to 32.7 mBq/m 3 and from 27.4 to 38.3 mBq/m 3 were found in the lake and river water samples, respectively. Mass balances of 22 Na from the watershed to river and lake were constructed by considering the atmospheric deposition of 22 Na. The mean residence times of 22 Na in the southern and northern basins of Lake Biwa were estimated as about 18 days and 5.4 years, respectively. Furthermore, the mean residence time of this atmospheric nuclide in the watershed was evaluated as about 7.3 years, whose value may be helpful in tracing the fate of contaminants with similar chemical properties in the watershed. The quantity of groundwater flow into the lake was also roughly estimated to be 1.6Â10 9 m 3 /yr from the specific activity of 22 Na/Na.

Current practice in estimating mercury runoff from the watershed in TMDL analysis assumes much of the atmospherically deposited mercury is available for transport to receiving waters; such estimates are overly conservative, and do not reflect the complex nature of mercury surface reactions. The time-dependence of mercury washoff is critical in assessing the variable availability of mercury to the receiving waters. This review illustrates the importance of the relationship between mercury deposition and runoff efficiency for common watershed surfaces. With such fundamental information, better quantitative estimates of mercury loading to marine/freshwater bodies, design of runoff control practices, and land use planning can be developed. transport in runoff . This lack of availability is especially true for particulate bound toxicants. As vegetated or permeable surfaces are considered, it is possible for the watershed to act as a permanent sink for a portion of the deposited mercury.

The physico-chemical characteristics of granulated sludge lead us to develop its use as a packing material in air biofiltration. Then, the aim of this study is to investigate the potential of unit systems packed with this support in terms of ammonia and hydrogen sulfide emissions treatment. Two laboratory scale pilot biofilters were used. A volumetric load of 680 g H 2 S m À3 empty bed day À1 and 85 g NH 3 m À3 empty bed day À1 was applied for eight weeks to a unit called BGSn (column packed with granulated sludge and mainly supplied with hydrogen sulfide); a volumetric load of 170 g H 2 S m À3 empty bed day À1 and 340 g NH 3 m À3 empty bed day À1 was applied for eight weeks to the other called BGNs (column packed with granulated sludge and mainly supplied with ammonia). Ammonia and hydrogen sulfide elimination occur in the biofilters simultaneously. The hydrogen sulphide and ammonia removal efficiencies reached are very high: 100% and 80% for BGSn; 100% and 80% for BGNs respectively. Hydrogen sulfide is oxidized into sulphate and sulfur. The ammonia oxidation products are nitrite and nitrate. The nitrogen error mass balance is high for BGSn (60%) and BGNs (36%). This result could be explained by the denitrification process which would have occurred in anaerobic zones. High percentages of ammonia or hydrogen sulfide are oxidized on the first half of the column. The oxidation of high amounts of hydrogen sulfide would involve some environmental stress on nitrifying bacterial growth and activity.

The study of the water gas shift reaction performance in terms of complete conversions is presented. The behaviour of a membrane reactor (MR) consisting of a tubular microporous ceramic within a thin palladium membrane was compared with a membrane reactor using a palladium/silver membrane. Membranes were developed in order to obtain a metallic layer thick enough to avoid any defects of the metallic layer and ensure infinite hydrogen selectivity with respect to other gases. The lumen of both membrane reactors was filled with the catalyst. The experiments were carried out by using nitrogen as inert gas in the streep having a flow rate ranging between 1 ×10 − 4 and 4×10 − 4 mol s − 1 in co-current and counter-current mode in the temperature range 331-350°C and in the feed molar flow range 3.05 ×10 − 5-7.1×10 − 5 mol s − 1. Hydrogen was the only one gas passing through both membranes. A complete separation of hydrogen from the other gases of the reaction system was obtained. The water gas shift reaction conversion was close to 100% by using the Pd/Ag membrane. A mathematical model was developed to interpret the experimental data. It described the system under isothermal conditions and considered an axial differential mass balance in terms of partial pressure for each chemical species. The simulation study and the experimental results show a satisfactory agreement and both highlight the possibility to shift towards 100% the conversion of the considered reaction.

In mountain regions, wind is known to cause inhomogeneous snow distribution. Recently, it has been shown that this snow distribution can be explained by considering high-resolution flow fields created by numerical flow models. It has also been shown that small-scale deposition features are mainly caused by saltation and snow redistribution, larger-scale inhomogeneities are caused by preferential deposition, and the total deposition patterns correlate well with the mean wind speeds. On the basis of the strong correlation between wind fields and snow depth, we develop a new empirical parameterization of preferential deposition of precipitation, which is only governed by the mean flow field. The parameterization is based on case studies, where the physically based model for wind-induced snow transport ALPINE3D was combined with wind fields from the regional atmospheric model ARPS (Advanced Regional Prediction System). The parameterization, along with ARPS wind fields and a distributed energy balance snowmelt model, is used to simulate the 2006/2007 accumulation season over the catchment of Haut Glacier d'Arolla, a glacierized Alpine basin. The results were validated with a Light Detection and Ranging (LiDAR)-derived fully distributed high-resolution dataset of snow depth and show that the developed parameterization, despite being simple, is able to largely reduce the difference between modelled and measured snow depth and is suitable for application in glacier mass balance models.

In the last few years, regulatory focus has been on nutrient management from animal feeding operations with recent emphasis on air emissions. The main challenge is establishing current emission levels and determining best methodologies for measuring these accurately. Methodologies to measure air emissions under field and research conditions are currently available and are being further developed, but extensive challenges exist as to accuracy and precision of the different methods. Current best estimates are based on a mass balance modeling approach [1], but due to lack of current biologically generated data to use in the models, nutrient excretion and emission levels appear to be overestimated by these models. Extensive work is being conducted using dietary strategies to reduce nitrogenous excretions from poultry, but the impact of these on air emissions is not always defined. Litter management strategies that reduce volatilization of nitrogenous and other compounds have shown promise and are being further developed. Flock, house, and whole farm management strategies are also being successfully implemented and further developed. The magnitude of the potential impact on air emissions of each of these strategies is still in question. There is no question, however, as to the need for the use of whole farm systems that implement different strategies at all management levels if large decreases in air emissions from animal feeding operations are to be achieved.

This review highlights the many roles mass spectrometry plays in the discovery and development of new therapeutics by both the pharmaceutical and the biotechnology industries. Innovations in mass spectrometer source design, improvements to mass accuracy, and implementation of computer-controlled automation have accelerated the purification and characterization of compounds derived from combinatorial libraries, as well as the throughput of pharmacokinetics studies. The use of accelerator mass spectrometry, chemical reaction interface-mass spectrometry and continuous flow-isotope ratio mass spectrometry are promising alternatives for conducting mass balance studies in man. To meet the technical challenges of proteomics, discovery groups in biotechnology companies have led the way to development of instruments with greater sensitivity and mass accuracy (e.g., MALDI-TOF, ESI-Q-TOF, Ion Trap), the miniaturization of separation techniques and ion sources (e.g., capillary HPLC and nanospray), and the utilization of bioinformatics. Affinity-based methods coupled to mass spectrometry are allowing rapid and selective identification of both synthetic and biological molecules. With decreasing instrument cost and size and increasing reliability, mass spectrometers are penetrating both the manufacturing and the quality control arenas. The next generation of technologies to simplify the investigation of the complex fate of novel pharmaceutical entities in vitro and in vivo will be chip-based approaches coupled with mass spectrometry.

Buffer strips are an efficient and economical way to reduce agricultural nonpoint source pollution. Local researches are necessary to gain information on buffer performance, with particular emphasis on narrow buffers. The effect of a 6 m buffer strip (BS) in reducing runoff, suspended solids and nutrients from a field growing maize, winter wheat and soybean was assessed in a field experiment conducted in North-East Italy during 1998-2001. The BS was composed of two rows of regularly alternating trees (Platanus hybrida Brot.) and shrubs (Viburnum opulus L.), with grass (Festuca arundinacea L.) in the inter-rows.

The European directive 2000/53/EC implies a "reuse and recovery" rate for end-of-life vehicles (ELVs) of 95% to be reached by the year 2015. One of the options to increase the actual average European "reuse and recovery" rate of approximately 78% (EU 15, 2008) is incineration of automotive shredder residue (ASR) with energy-recovery. The mass balance and the congener fingerprints for PCDD/Fs, dioxin-like PCBs, PCBs and PAHs in a real scale fluidized bed combustor (FBC) incinerating 25% ASR with 25% refuse derived fuel (RDF) and 50% waste water treatment sludge (WWT sludge) were investigated. The PCDD/F, dioxin-like PCB, PCB and PAH concentrations in this input waste mix were more than hundred times higher than in the usual waste feed of the incinerator (30% RFD and 70% WWT sludge). In the outputs of the FBC, however, the concentrations of these POP groups were comparable or only slightly higher than in the outputs generated during the incineration of the usual waste feed. The considered POPs in the waste were destroyed efficiently and the formation of new POPs during cooling of the flue gas appeared to a large extent independent of the POP concentrations in the incinerated waste.

In order to quantify the fate of nutrients originating from shrimp pond waste, mass balances of carbon (C) and nitrogen (N) were compared from a mangrove creek that received shrimp farm effluent to those in an adjacent control creek that did not receive effluent. The annual C input from the shrimp farm exceeded carbon metabolism in creek water and sediments, indicating high sedimentation and burial of excess organic material in the upper reaches of the effluent creek. The rate of natural N flow was small compared with the rate of N supply from pond effluent. Ammonium uptake in creek water and sediment denitrification each accounted for less than 10% of the annual effluent N supply. Immediately downstream from the farm discharge point, mineralisation and release of dissolved inorganic and organic N from the sediments were not greatly enhanced compared to the control creek, despite 25% of the annual N supply and 10% of the annual C supply depositing in proximity to the discharge point. Further downstream, rapid bacterial growth and high rates of primary production were controlled by very high micro-zooplankton grazing rates. The remaining nutrients were exported from the upper reaches to the seaward end of the effluent creek via tidal flushing. On an annual basis, the upper reaches of the creek appeared to mineralise only a small fraction of the nutrients derived from the shrimp farm wastes. However, discharge of pond waste C and N during shrimp harvest periods did not cause eutrophication further downstream, probably due to a combination of physical mechanisms (intensive tidal flushing) and biological nutrient transformations by pelagic microbes and their subsequent grazing by micro-zooplankton and fish.

Ozone can cause many health problems, including exacerbation of asthma, throat irritation, cough, chest ache, shortness of breath, and respiratory infections. Air cleaners are one of the sources of indoor ozone, and thus the evaluation of ozone generated by air cleaners is desired significant issue. Most evaluation methods proposed are based on chamber tests. However, the adsorption and desorption of ozone on the wall of test chamber and the deposition of ozone resulted from the surface reaction can influence the evaluation results. In this study, we developed a mass balance model that took the adsorption, desorption and deposition of ozone into consideration to evaluate the effective ozone emission rates of six selected air cleaners. The experiments were conducted in a stainless steel chamber with a volume of 11.3 m 3 at 25 C and 60% relative humidity. The adsorption, desorption and deposition rate constants of ozone obtained by fitting the model to the experimental data were k a ¼ 0.149 AE 0.052 m h À1 , k d ¼ 0.013 AE 0.007 h À1 , and k r ¼ 0.050 AE 0.020 h À1 , respectively. The effective ozone emission rates of Air Cleaners No. 1, 2, and 3 ranged between 13,400e24,500 mg h À1 , 7190e10,400 mg h À1 , and 4880e6560 mg h À1 , respectively, which were more stable than those of No.4, 5, and 6. The effective ozone emission rates of Air Cleaners No. 4, 5, and 6 increased with the time of operation which might be relevant to the decrease of ozone removal by the "aging" filter installed in these cleaners. The removal of toluene and formaldehyde by these six air cleaners were also evaluated and the clean air delivery rates (CADRs) of these two pollutants ranged from non-detectable to 0.42 AE 0.08 m 3 h À1 , and from non-detectable to 0.75 AE 0.07 m 3 h À1 , respectively. The CADRs showed an insignificant relationship with the effective ozone emission rates. Thus, the removal of toluene and formaldehyde might be resulted from the adsorption on the filters and the decomposition by the high-voltage electric discharge or the ionization that generated ozone.

Soil-plant potassium (K) dynamics were studied using a long-term field experiment in order to evaluate the plant performance and K delivering capacity of the soil parent material. Rye grass (Lolium perenne L.) based rotations on a loamy sand derived from granitic bedrock were studied over 30 years with two K-fertilisation regimes, nil (K0) and 65 kg K ha −1 yr −1 . Mineralogical and chemical methods were combined to identify and quantify soil K resources including the partitioning of K between minerals. Two or three cuts were taken annually and herbage yield and composition together with exchangeable soil K were analysed. Herbage yield declined with time and significantly reduced when the K concentrations approached 1%. The grass K concentration also declined over time and stabilized at around 0.5-0.7% (dw) in K0 in all cuts. Input-output mass balances showed an accumulated net K off-take (deficit) of 1,100 kg ha −1 , i.e. 35 kg ha −1 yr −1 . With an exchangeable K pool of 100 kg ha −1 (in the rooting zone 0-40 cm) this indicated a substantial release of K from mineral sources, most probably biotite and hydrobiotite. Assuming a similar net off-take was continued then this particular mineralogical K source would be depleted within two centuries. The study illustrates the strength of combining long-term field experimental data with state of the art quantitative mineralogical methods in order to assess site-specific resources which can form a basis to evaluate the sustainability of different management practices.

Continuous measurements of the surface water CO 2 partial pressure (pCO 2) and the chlorophyll a fluorescence were performed in the Baltic Sea using a fully automated measurement system deployed on a cargo ship. The ship commuted regularly at two day intervals between the Mecklenburg Bight (Luebeck) and the Gulf of Finland (Helsinki). The pCO 2 data collected during June 2003 and September 2004 were used to identify biological production events such as the spring bloom and the midsummer cyanobacteria bloom in five different sub-regions. To quantify the net biomass production, the decrease of the total CO 2 , N C T (normalized to a uniform alkalinity), during the production periods was calculated using the pCO 2 , temperature and salinity records and the mean alkalinity. Taking into account the CO 2 air/sea exchange and the formation of dissolved organic carbon, a simple mass balance yielded the net production of particulate organic carbon which represents the total biomass. The chlorophyll a concentrations obtained from the fluorescence data showed peaks that in most cases coincided with the production maxima and thus supported the interpretation of the pCO 2 data. The production during both the spring bloom (2004) and the midsummer nitrogen fixation period (2003) increased by a factor of about three from the southwest to the northeast. For the spring bloom our estimates were significantly higher than those based on the winter nutrient supply and Redfield C / N and C / P ratios. This indicated the existence of additional nutrient sources such as dissolved organic nitrogen, early nitrogen fixation and preferential P mineralization. Midsummer N C T minima were observed only in 2003 and used to quantify the nitrogen fixation activity and to characterize its interannual variability.

Sub-basins within the New York/New Jersey (NY/NJ) Harbor host variable amounts and sources of polycyclic aromatic hydrocarbons (PAHs). Analyses of radionuclides 137Cs and 7Be were used to assign approximate dates to individual sections of sediment cores collected from four major sub-basins of the harbor complex. Sampling sites range from heavily contaminated Newark Bay and Passaic River to less contaminated Raritan Bay and Jamaica Bay. PAHs were identified with GC–MS and quantified by GC respectively. Gas chromatography–isotope ratio mass spectrometry (GC/IRMS) was applied to determine δ13C values of pyrene (δ13CPy), a principal 4 ring parent PAH. Two end-member PAH source components, petroleum-related PAHs (PRPAH) and combustion-related PAHs (CRPAH), were calculated from a carbon isotopic mass balance equation based on assumptions that petroleum-related δ13CPy is −29‰, and that combustion-derived δ13CPy is −24‰. Temporal trends of PRPAH in these cores are similar to those of the petroleum-derived unresolved complex mixture (UCM), whereas CRPAH resembled trends of “Total” PAH (TPAH). Three molecular ratios, fluoranthene to fluoranthene plus pyrene (Fl/(Fl + Py)), high molecular weight 4–6 ring PAH to total PAH (Ring456/TPAH) and parent to total (Par/(Par + Alkyl)), correlate strongly with each other, and show a moderate to strong positive correlation with δ13CPy. In contrast, the ratios of anthracene to phenanthrene plus anthracene (A/(Pa + A)), benzo[a]anthracene to benzo[a]anthracene plus chrysene (BaA/(BaA+Chy)), and indeno[1,2,3-cd]pyrene to indeno[1,2,3-cd]pyrene plus benzo[ghi]perylene (IP/(IP + Bghi)) show no, weak, or even negative correlation with the four well correlated ratios (δ13CPy, Par/(Par + Alkyl), Fl/(Fl + Py), and Ring456/TPAH). Combined application of the four well correlated molecular indicators suggests that PAH contribution from combustion became more important in most areas of the NY/NJ Harbor during the last three decades of the 20th century.

In the upper Hunter Valley of New South Wales a high level teschenitic sill complex emplaced into Permian coal measures derives from parent magmas which were themselves crystal fractionation products of alkali basaltic melts. The sills crystallised in situ and produced a spectrum of rock types ranging from olivine teschenite to teschenite, syenoteschenite and, ultimately, syenite. The olivine teschenites are also enriched in biotite and are crudely interlayered with teschenite and syenoteschenite. The lineage from olivine teschenite to syenoteschenite is characterised by a progressive decrease in olivine and a build-up of alkaline mesostasis which is accompanied by strong chemical zonation in abutting silicate minerals. The alkaline mesostasis and syenites are identical mineralogically. Primary crystallisation of olivine in the olivine teschenite-teschenite-syenoteschenite continuum and data from coexisting iron-titanium oxide pairs suggest that oxygen fugacity was constrained to a path parallel to the QFM buffer curve. Absence of olivine from the alkaline mesostasis and syenite veins, together with the appearance of sphene, indicates buffering of oxygen fugacity by other assemblages (probably annite-alkali feldspar-magnetite) and generally higherfO2 in the residual liquids. Here, a build-up of CO2, F and C1, in addition to HaO, influenced the relative stabilities of the pyroxene and amphibole minerals. Major and trace element data support an in situ, progressive congelation model for crystallisation. Mass balance solutions require participation of all phases to produce acceptable residuals. Simple mixing calculations suggest that syenoteschenite consists of teschenite plus approximately 40% syenite, in close agreement with the observed modal mineralogy. Segregation of syenite from syenoteschenite probably occurred when the residual liquid, as represented by mesostasis, reached a critical volume of around 40%.

High precision TIMS 230Th/ 232Th isotope ratios are presented from a suite of lavas which span the length of the Lesser Antilles island arc. Compositions vary from low K, tholeiitic lavas with low *'Sr/ 86Sr in the north, to high K, talc-alkaline to alkalic lavas with higher s'Sr/ ?Sr in the south. The northern lavas are characterised by tz3'Th/ 238U) < 1 whereas those from the south tend towards secular equilibrium and occasionally have (230Th/ 238U) > 1. A three-component model is required for magma genesis in the Lesser Antilles. Sediments from the subducting slab melt and variably enrich the mantle wedge, while the subducting oceanic crust dehydrates, releasing fluids enriched in U, Ba, Sr and K, but with negligible Th and low "Sr/ *?Sr, which promote partial melting in the wedge. Ta/Zr increases with " Sr/ 86Sr southwards along the arc and this is inferred to reflect increasing enrichment of the mantle wedge through the addition of partial melts of subducted sediment. Mass balance calculations are consistent with a relatively constant fluid flux (except for U) and little variation in the degree of partial melting (lo-15%) along the arc, and they suggest that the sediment contribution to the arc lavas increases from -2% in the north to -15% in the south. In the northern parts of the arc, the addition of U by these fluids overprints any increases in Th/U that might have been caused by partial melting, and results in lavas with (230Th/ 238U) < 1. Further south, the fluid signature is swamped by partial melts of the subducted sediments, and the (230Th/ 238U) ratios tend towards 1. Assuming that (230Th/ 238U) ratios < 1 reflect the preferential mobility of U in aqueous fluids, the bulk of the LIL element abundances, and the elevated "Sr/ ?3r ratios in the talc-alkaline and alkalic lavas, were not transported by subduction zone fluids. A three-component mixing model is developed to calculate (230Th/232Th) ratios at the time of formation of the measured U/Th. The time required for radioactive decay from these calculated ratios to the measured (230Th/ 232Th) ratios provides an upper limit on the transport time for the relatively high U/Th fluid component through the wedge of -90000 yr. If -50000 yr U-Th isochrons from Soufritre on St. Vincent reflect typical magma chamber residence times for this island arc, this leaves ascent rates > 1 m yr-', -40000 yr for transport from the slab to the crust. Such constraints require which imply channelled flow through the mantle wedge.

Vacuum pyrolysis of pure PVC at various temperatures and under a total pressure of 2 kPa has been performed to identify and quantify the main pyrolysis products obtained during the different stages of thermal degradation. A system consisting of a bench scale batch reactor with a condensation train was used to collect the pyrolysis products. The main gaseous and liquid

Convection driven by sediment particles may play an important role in sedimentation from the base of buoyant (hypopycnal) plumes, for example, fluvial plumes in stratified estuaries and lakes, black smokers on the ocean floor, volcanic clouds, and coastal currents. In addition to the well-known double-diffusive convection mechanism, another mode of convective instability development is by settling across the density interface. We performed laboratory experiments to investigate this fingering/convective instability mechanism and its effect on particle distribution in the water column and deposition at the bed. A simple theoretical model of finger formation at a fluid density interface is developed based on an analogy with thermal/plume formation at a flat heated plate. This model, which involves a thickening interface layer that becomes gravitationally unstable relative to the ambient fluid, is in good agreement with measurements of finger size and instability wavelength from visualization experiments. Since fingering at the density interface drives larger-scale convection in the fluid below, a mass balance model of the lower layer, assuming strong mixing (i.e., uniform sediment concentration) is successfully applied to predict sediment concentration in the water column and deposition at the bed. Strong mixing can be assumed since convective velocities are usually much greater than the particle fall velocities. As convection proceeds, the sedilnent concentrations in the two layers approach each other and convection will die out. Using the model equations, we develop analytical expressions for the time when convection ceases and the portion of sediment remaining in the water column.

Two a-alumina ceramic membranes (0.2 and 0.8 jam pore sizes) and a surface-modified polyacrylonitrile membrane (0.1 jam pore size) were tested with an oily water, containing various concentrations (250-1000 ppm) of heavy crude oil droplets of 1-10 ~tm diameter. Significant fouling and flux decline were observed. Typical final flux values (at the end of experiments with 2h of filtration) for membranes at 250ppm oil in the feed are ~30-40kg m-2 h-1. Increased oil concentrations in the feed decreased the final flux, whereas the crossflow rate, transmembrane pressure, and temperature appeared to have relatively little effect on the final flux. In all cases, the permeate was of very high quality, containing <6 ppm total hydrocarbons. The addition of suspended solids increased the final membrane flux by one order of magnitude. It is thought that the suspended solids adsorb the oil, break up the oil layer, and act as a dynamic or secondary membrane which reduces fouling of the underlying primary membrane. Resistance models were used to characterize the type of fouling that occurs. Both the 0.2 jam and the 0.8 jam ceramic membranes appeared to exhibit internal fouling followed by external fouling, whereas external fouling characterized the behavior of the 0.1 jam polymer membrane from the beginning of filtration. Examination of the external fouling layer showed a very thin hydrophobic oil layer adsorbed to the membrane surface. This oil layer made the membrane surface hydrophobic, as demonstrated by increased water-contact angles. The oil layer proved resistant to removal by hydrodynamic (shear) methods. By extracting the oil layer with tetrachloroethylene, followed by IR analysis, its average thickness at the end of a 2 h experiment under typical conditions was determined to be 60 ~tm for the 0.2 jam ceramic membrane and 30 jam for the 0.1 jam polymer membrane. These measured amounts of oil associated with the membrane at the end of the experiments are in good agreement with those determined from a simple mass balance, in which it is assumed that all of the oil associated with the permeate collected is retained on or in the membrane, indicating that the tangential flow did not sweep the rejected oil layer to the filter exit.

An analytical method has been developed to differentiate the electrical and thermal resistance of the PEM fuel cell assembly in the fuel cell operating conditions. The usefulness of this method lies in the determination of the electrical resistance based on the polarization curve and the thermal resistance from the mass balance. This method also paves way for the evaluation of cogeneration from a PEMFC power plant. Based on this approach, the increase in current and resistance due to unit change in temperature at a particular current density has been evaluated. It was observed that the internal resistance of the cell is dependent on the electrode fabrication process, which also play a major role in the thermal management of the fuel cell stack.

We have selected seven profiles located in a diapiric formation in the North of Spain. The profiles have been analyzed for the mineralogy and the chemical composition of original materials, soils developed above them and clay fractions. Three soils formed on basic rock of volcanic origin (ophite) and rich in alterable minerals, three others formed on clay marl and one soil formed on gypsiferous marl. Plagioclases, pyroxenes, vermiculites, and biotites are the main minerals found in the soil samples and ophitic rocks. Biotite, smectite, chlorite and interstratified chlorite-vermiculite make up the predominant mineralogical association in the clay fraction of the soils. Calcite, biotite and on top of all chlorite are the main minerals in the marls and the soils developed on them, with gypsum predominant in the gypsiferous marl. The mineralogy of its clay fraction is comprised mainly of chlorite and biotite. The variations in content of Al 2 O 3 , TiO 2 and Na 2 O in the ophites are considered to be associated with the differences in the evolution of the pyroxenes. The variability of the chemical composition of the Keuper sediments and the soils is attributed more to the chaotic disposition of the Triassic materials in the formation of the diapir than to intense chemical weathering. The low concentrations of silica, iron, and aluminum extractable with ammonium oxalate indicate the low proportion of non-crystalline products. Fundamentally, it is the semiarid conditions in the study zone, together with the processes of extrusion and hydrothermal activity affecting the formation of the diapir, that are responsible for the genesis of the minerals.

Catch crops can effectively decrease nitrate leaching in arable cropping systems but their longterm impacts on nitrogen mineralization are not well known. This study quantified the effects of continuous catch crops on net N mineralization, crop N uptake, crop N use efficiency and N leaching in three long-term (13-17 years) field experiments in northern France. Mustard was grown every year at Boigneville, radish every year at Thibie and ryegrass every 2 years at Kerlavic. The mean N content of catch crop residues at these sites was 33, 36 and 35 kg ha −1 yr −1 and their mean C:N ratio was 13, 17 and 28, respectively. Net mineralization was calculated with a mass balance of soil mineral N using measured inputs and outputs. Catch crop establishment enhanced annual mineralization by on average 26, 18 and 9 kg N ha −1 yr −1 respectively during the 13-17 year period. The difference in mineralization rate between catch crop and control treatments (extra mineralization) was positive from the first year at Boigneville, whereas it was negative or nil during the first 3-5 years at Thibie and Kerlavic. At the latter sites, the extra mineralization rate increased significantly over time at a rate of 2.0 and 2.6 kg N ha −1 yr −2 . At the end of the experiment, cumulative extra mineralization represented 72%, 60% and 23% of the total N added by catch crop residues at Boigneville, Thibie and Kerlavic, respectively. Repeated catch crops significantly increased N uptake and N use efficiency by main crops at Kerlavic and Thibie, but not at Boigneville. The efficiency of catch crops in reducing N leaching persisted over the years at all sites. A model simulating C and N dynamics during catch crop decomposition was able to reproduce the pattern of extra N mineralization kinetics with the various catch crop species, but underestimated the range of variation between sites. Better predictions were obtained when C or N inputs due to catch crops were increased by 10-57%, suggesting that the actual inputs could be markedly greater than those measured in catch crop residues. According to the model, the C: N ratio of catch crop residues largely explained differences in mineralization due to different catch crop species.