Construction of avulsion potential zone model for Kulik River of Barind Tract,India and Bangladesh

Avulsion is a natural fluvial process but considered it as a hazard in the populated region due to the chance of immense failure of lives and properties. So, early warning indicates that the zone of avulsion can facilitate the people living there. About 317 numbers of local and regional historical imprints of channel cutoff along river Kulik claim the need of this work. The present study tried to identify avulsion potential zone (APZ) of Kulik river of Indo-Bangladesh using multi-parametric weighted combination approach. Analytic hierarchy approach (AHP) is applied for weighting the used parameters. Avulsion potential model clearly exhibits that 9.51-km stream segment of middle and lower catchment is highly susceptible for avulsion especially during sudden high discharge and earthquake incidents. There is also high chance of channel avulsion following the existing Paleo-avulsion courses and left channels. Hard points can also be erected alongside the main channel for resisting channel avulsion propensity.     

Pond bank access as an approach for managing toxic cyanobacteria in beef cattle pasture drinking water ponds

Forty-one livestock drinking water ponds in Alabama beef cattle pastures during were surveyed during the late summer to generally understand water quality patterns in these important water resources. Since livestock drinking water ponds are prone to excess nutrients that typically lead to eutrophication, which can promote blooms of toxigenic phytoplankton such as cyanobacteria, we also assessed the threat of exposure to the hepatotoxin, microcystin. Eighty percent of the ponds studied contained measurable microcystin, while three of these ponds had concentrations above human drinking water thresholds set by the US Environmental Protection Agency (i.e., 0.3 μg/L). Water quality patterns in the livestock drinking water ponds contrasted sharply with patterns typically observed for temperate freshwater lakes and reservoirs. Namely, we found several non-linear relationships between phytoplankton abundance (measured as chlorophyll) and nutrients or total suspended solids. Livestock had direct access to all the study ponds. Consequently, the proportion of inorganic suspended solids (e.g., sediment) increased with higher concentrations of total suspended solids, which underlies these patterns. Unimodal relationships were also observed between microcystin and phytoplankton abundance or nutrients. Euglenoids were abundant in the four ponds with chlorophyll concentrations >?250 μg/L (and dominated three of these ponds), which could explain why ponds with high chlorophyll concentrations would have low microcystin concentrations. Based on observations made during sampling events and available water quality data, livestock-mediated bioturbation is causing elevated total suspended solids that lead to reduced phytoplankton abundance and microcystin despite high concentrations of nutrients, such as phosphorus and nitrogen. Thus, livestock could be used to manage algal blooms, including toxic secondary metabolites, in their drinking water ponds by allowing them to walk in the ponds to increase turbidity.     

Combining sap flow and eddy covariance approaches to derive stomatal and non-stomatal O3 fluxes in a forest stand

Stomatal O₃ fluxes to a mixed beech/spruce stand (Fagus sylvatica/Picea abies) in Central Europe were determined using two different approaches. The sap flow technique yielded the tree-level transpiration, whereas the eddy covariance method provided the stand-level evapotranspiration. Both data were then converted into stomatal ozone fluxes, exemplifying this novel concept for July 2007. Sap flow-based stomatal O₃ flux was 33% of the total O₃ flux, whereas derivation from evapotranspiration rates in combination with the Penman-Monteith algorithm amounted to 47%. In addition to this proportional difference, the sap flow-based assessment yielded lower levels of stomatal O₃ flux and reflected stomatal regulation rather than O₃ exposure, paralleling the daily courses of canopy conductance for water vapor and eddy covariance-based total stand-level O₃ flux. The demonstrated combination of sap flow and eddy covariance approaches supports the development of O₃ risk assessment in forests from O₃ exposure towards flux-based concepts.     

Organocopper complexes during roxarsone degradation in wastewater lagoons

Background, aim, and scope  

Organoarsenical-containing animal feeds that promote growth and resistance to parasites are mostly excreted unchanged, ending up in nearby wastewater storage lagoons. Earlier work documented the partial transformation of organoarsenicals, such as, 3-nitro-4-hydroxyphenylarsonic acid (roxarsone) to the more toxic inorganic arsenate [As(V)] and 3-amino-4-hydroxyphenylarsonic acid (3-AHPAA). Unidentified roxarsone metabolites using liquid chromatography coupled to inductively coupled plasma mass spectrometry (LC/ICP-MS) were also inferred from the corresponding As mass balance. Earlier batch experiments in our laboratory suggested the presence of organometallic (Cu) complexes during relevant roxarsone degradation experiments. We hypothesized that organocopper compounds were complexed to roxarsone, mediating its degradation in field-collected swine wastewater samples from storage lagoons. The objective of this study was to investigate the role of organometallic (Cu) complexes during roxarsone degradation under aerobic conditions in swine wastewater suspensions, using electrospray ionization mass spectrometry (ES-MS).     

Quantifying trace gas emissions from composite landscapes: A mass-budget approach with aircraft measurements

Quantifying trace gas emissions and the influence of surface exchange processes on the atmosphere is a necessary step towards the control of global greenhouse gas emissions and reliability of air quality models. This paper proposes a procedure based on the mass balance method and implemented on highly resolved aircraft data. It allows one to estimate surface exchanges on areas of several km² and heterogeneous features exploiting the characteristics of convective boundary layer during steady state conditions that permit the estimation of emission/absorption terms as functions of advective fluxes only. A nonparametric approach is adopted and the fluxes on the surface of a virtual box surrounding the area of interest are reconstructed on the basis of scalar densities and wind vectors using Shepard functions. Two different techniques are also proposed to face lack of data on the top surface of the box. The method has been applied to experimental data coming from measurement campaigns on two different sites. It provides realistic estimates of the CO₂ emission/absorption in the considered areas that are in good agreement with CO₂ fluxes evaluated by Airborne Eddy Covariance and confirm the suitability of the proposed approach for the assessment of turbulent exchange of trace gases by composite landscapes. Uncertainties on the estimated emissions due to both propagation of the experimental error and interpolation have been quantified by bootstrap analysis as 6%.     

Economic Impact of Mass Production of Alternative Low Emission Automotive Power Systems

The study considers a range of possible effects on the transportation industry, satellite industries, the labor market, and the economy which may be anticipated in the event mass production of unconventional low emission automotive propulsion systems should occur, whether as a consequence of federal intervention, or not. A postulated 1 976 Otto Cycle Internal Combustion Engine equipped with a dual catalyst manifold reactor and other “conventional” emission control devices was compared in detail with a Regenerative Free Turbine Engine and a Rankine Cycle Engine, as specified by the contracting agency. Manufacturing costs, operating and ownership costs, consumer demand, inter-industry effects, employment, resource requirements, and international trade implications were analyzed in depth under a number of plausible sets of policy constraints and parametric variations. Principal conclusions are that conversion over a 10 year period is feasible, that manufacturing cost differentials are less critical than fuel consumption and cost differentials, that industry/employment impacts are minor, and that resource/trade effects are dominated by petroleum imports. Implications for federal policy are discussed.     

Inhalation dose assessment of indoor radon progeny using biokinetic and dosimetric modeling and its application to Jordanian population

High indoor radon concentrations in Jordan result in internal exposures of the residents due to the inhalation of radon and its short-lived progeny. It is therefore important to quantify the annual effective dose and further the radiation risk to the radon exposure. This study describes the methodology and the biokinetic and dosimetric models used for calculation of the inhalation doses exposed to radon progeny. The regional depositions of aerosol particles in the human respiratory tract were firstly calculated. For the attached progeny, the activity median aerodynamic diameters of 50 nm, 230 nm and 2500 nm were chosen to represent the nucleation, accumulation and coarse modes of the aerosol particles, respectively. For the unattached progeny, the activity median thermodynamic diameter of 1 nm was chosen to represent the free progeny nuclide in the room air. The biokinetic models developed by the International Commission on Radiological Protection (ICRP) were used to calculate the nuclear transformations of radon progeny in the human body, and then the dosimetric model was applied to estimate the organ equivalent doses and the effective doses with the specific effective energies derived from the mathematical anthropomorphic phantoms. The dose conversion coefficient estimated in this study was 15 mSv WLM⁻¹ which was in the range of the values of 6-20 mSv WLM⁻¹ reported by other investigators. Implementing the average indoor radon concentration in Jordan, the annual effective doses were calculated to be 4.1 mSv y⁻¹ and 0.08 mSv y⁻¹ due to the inhalation of radon progeny and radon gas, respectively. The total annual effective dose estimated for Jordanian population was 4.2 mSv y⁻¹. This high annual effective dose calculated by the dosimetric approach using ICRP biokinetic and dosimetric models resulted in an increase of a factor of two in comparison to the value by epidemiological study. This phenomenon was presented by the ICRP in its new published statement on radon.     

Radiological maps for Trabzon, Turkey

The activity concentrations and absorbed gamma dose rates due to primordial radionuclides and ¹³⁷Cs have been ascertained in 222 soil samples in 18 counties of the Trabzon province of Turkey using a HPGe detector. The mean activity concentrations of ²³⁸U, ²³²Th, ⁴⁰K and ¹³⁷Cs in soil samples were 41, 35, 437 and 21 Bq kg⁻¹, respectively. Based on the measured concentrations of these radionuclides, the mean absorbed gamma dose in air was calculated as 59 nGy h⁻¹ and hence, the mean annual effective dose due to terrestrial gamma radiation was calculated as 72 μSv y⁻¹. In addition, outdoor in situ gamma dose rate (D) measurements were performed in the same 222 locations using a portable NaI detector and the annual effective dose was calculated to be 66 μSv y⁻¹ from these results. The results presented in this study are compared with other parts of Turkey. Radiological maps of the Trabzon province were composed using the results obtained from the study.     

Arsenic strongly associates with ferrihydrite colloids formed in a soil effluent

Arsenic mobility may increase in liquid phase due to association with colloidal Fe oxides. We studied the association of As with Fe oxide colloids in the effluent from water-saturated soil columns run under anoxic conditions. Upon exfiltration, the solutions, which contained Fe²⁺, were re-aerated and ferrihydrite colloids precipitated. The entire amount of effluent As was associated with the ferrihydrite colloids, although PO₄³⁻, SiO₄⁴⁻, CO₃²⁻ and dissolved organic matter were present in the effluent during ferrihydrite colloid formation. Furthermore, no subsequent release of As from the ferrihydrite colloids was observed despite the presence of these (in)organic species known to compete with As for adsorption on Fe oxides. Arsenic was bound via inner-sphere complexation on the ferrihydrite surface. FTIR spectroscopy also revealed adsorption of PO₄³⁻ and polymerized silica. However, these species could not impede the quantitative association of As with colloidal ferrihydrite in the soil effluents.