bluuebunny/crossref_metadata_2025_split huggingface dataset:
Isotherms of Cadmium Sorption Density
Authors: Schulte Andreas , Beese Fritz 
Published: July 2010

AbstractTo study Cd sorption, 16 soil samples of different chemical soil reactions were taken and analyzed for their physical and chemical properties. Adsorption of ethylene glycol monoethyl ether (EGME) and N2 were determined to establish the specific surface area of the soils. The sorption of Cd was modeled on a per‐mass basis using the Langmuir and Freundlich equations as well as per‐surface area basis. Traditional sorption isotherms reveal the relation between the amount of Cd sorbed and the Cd concentration in the soil solution only for the soil under study and can therefore not be applied, or can be applied only with restrictions, to other soils. To meet the aim of modeling Cd sorption and mobility for other soils or locations differing greatly in their properties, we attempted to establish a generalizing sorption isotherm for soils of entirely different composition of the solid phase. On the basis of characteristic values the 16 soil samples taken were grouped into three different reaction types (aluminum‐hydroxide, silicate, and carbonate‐buffer range). The generalizing Cd sorption density isotherms for these different soil groups introduced in the following provide a useful mathematical model for the quantity‐intensity relation of Cd in soils that differ greatly in their specific surface area and their composition.
Leachability of Heavy Metals from Growth Media Containing Source‐Separated Municipal Solid Waste Compost
Authors: Sawhney B. L. , Bugbee G. J. , Stilwell D. E. 
Published: July 2010

AbstractThe leaching of heavy metals in source‐separated municipal solid waste (MSW) compost was determined by irrigation leaching of growth medium, admixed with varying amounts of compost, used for container grown plants. Perennial flowers (black‐eyed Susan, Rudbeckia hirta L.) were grown in 2‐L containers filled with the growth medium for a 10‐wk period. Rainfall was supplemented with overhead irrigation to supply 2 cm of water per day. Leachates collected over each 2‐wk period were analyzed for Cd, Cr, Cu, Ni, Pb, and Zn using atomic spectrometry. Concentrations of the heavy metals in the leachates increased with increasing proportions of MSW compost in the growth medium, but decreased with time of leaching. Leaching of the metals occurred at relatively high concentrations initially, followed by continued leaching at low concentrations. The initial leaching of heavy metals is attributed to their soluble or exchangeable forms and the subsequent slow leaching to the solid compounds. The concentrations of the heavy metals remained below the current drinking water standards in all treatments throughout the leaching period. The results thus suggest that contamination of ground water with heavy metals from source‐separated MSW compost applied as a soil amendment should be negligible, as the low concentrations in the leachates leaving the surface soil would be further attenuated by the subsoil.
Diel Changes in Iron(III)/Iron(II) in Effluent from Constructed Acid Drainage Treatment Wetlands
Authors: Wieder R. Kelman 
Published: July 2010

AbstractWithin the past decade, over 400 wetlands have been constructed to treat acid coal mine drainage (AMD). This study was undertaken to examine whether the efficiency with which constructed wetlands retain Fe present in AMD changes on a day‐night basis. In each of live AMD treatment wetlands, constructed with a different organic substrate (Sphagnum peat with limestone and fertilizer, Sphagnum peat, sawdust, straw‐manure, or mushroom compost), hourly sampling of inflow and outflow waters was conducted over a 19‐h (July 1990) and 24‐h period (May 1991). The chemical composition of the influent AMD was relatively stable over the duration of either sampling period. However, a striking diel pattern of shifts in the relative abundances of Fe2+ and Fe3+ in outflow waters was observed for both Sphagnum peat wetlands on both sampling dates, and for the straw‐manure and mushroom compost wetlands on the May 1991 sampling date. Prior to sunrise, 75 to 100% of the soluble Fe in outflow waters was Fe2+; prior to sunset, 62 to 88% of the soluble Fe was Fe3+. The documented did shifts in Fe3+ vs. Fe2+ abundance in outflow waters are greater in magnitude than any previously reported for a natural system and suggest that the cycling of Fe in AMD treatment wetlands is more dynamic than previously recognized and that standard daytime only sampling protocols are inadequate for assessing Fe retention‐release in AMD treatment wetlands.
Characterization and Settling of Solid Contaminants in Coal Mine Effluent
Authors: Zhou Z. , Bateman J. C. , Babchin A. , Bird G. W. 
Published: July 2010

AbstractGroundwater and runoff water at surface coal mines are often contaminated with suspended solids and should be treated before it is discharged to surface water bodies. The suspended solids in the waste effluent of the Highvale mine, Alberta, Canada, are dominantly micron and submicron sized, dioctahedral smectite. They form stable colloidal suspensions in sodium bicarbonate solutions. Theoretical consideration suggests that the suspended smectite can be flocculated by divalent cations such as Ca2+. Experimental results show that even a small amount (2.7 mM) of gypsum can flocculate the system and cause clays to settle. Depending on the solution composition, up to 85% of the effluent volume can be reduced after 24 h settling. The clay settling rate is affected by both NaHCO3 and gypsum concentrations. Without gypsum addition, no settling occurs regardless of NaHCO3 concentrations (2 to 30 mM). At a fixed NaHCO3 concentration, clay settling rate increases with an increase in gypsum concentration. At a fixed gypsum concentration, the rate of clay settling decreases with an increase in NaHCO3 concentration. The initial settling rate (ISR) can be correlated to the equivalent fraction of Na+ on the clay surface (ENa) or the exchangeable sodium percentage (ESP) on the smectite surface. Linear regression of the experimental data gives an empirical equation ISR = −0.170 − 0.459 log(ENa) with a regression coefficient of 0.917, where ENa = ESP/100. The functional relation between solid settling rate and ESP can be useful in the design of sediment ponds for treatment of coal mine effluent.
Solubility of Cyanide in Contaminated Soils
Authors: Meeussen Johannes C. L. , Keizer Meindert G. , van Riemsdijk Willem H. , de Haan Frans A. M. 
Published: July 2010

AbstractAt more than 200 sites in the Netherlands, the soil is contaminated with cyanide as a result of industrial activities. The mobility of cyanide, which mainly occurs in the form of iron cyanide complexes [Fe(CN)63− + Fe(CN)64−], plays an important role in predicting the possible hazards for the environment and human health. Cyanide mobility was investigated by assessing data on cyanide concentrations in groundwater at contaminated sites, and by examination of three contaminated soils. High cyanide concentrations were found in the groundwater at sites with alkaline soils (pH ca. 7.5), whereas much lower concentrations were found in the groundwater with acidic soils (pH ca. 4). This agreed with the assumption that the behavior of cyanide in these contaminated soils is largely governed by the solubility of Prussian blue [Fe4(Fe(CN)6)3(s)], which is relatively insoluble under acidic conditions. In the acidic soils, the concentrations in the soil water appeared to be close to equilibrium with Prussian blue. In alkaline soils this precipitate is extremely soluble. The presence of this material here was possibly the result of slow dissolution kinetics. Precipitation of Prussian blue in acidic soils does not prevent dissolved iron cyanide concentrations from exceeding Dutch soil quality standards.
Nitrous Oxide Emission in Relation to Soil Factors at Low to Intermediate Moisture Levels
Authors: Robertson Kerstin 
Published: July 2010

AbstractThe objective of this study was to investigate the N2O emission from agricultural soils (14 field plots/38 measurements) as a function of environmental and soil factors‐clay content, soil temperature, soil moisture, total organic C and N, water‐soluble organic C, nitrate and ammonium concentrations, and pH‐that are considered of significance for N2O production in soil. Passible relations were tested by multiple linear regression and multivariate data analysis (PLS). A significant (P ≤ 0.05) relation (linear regression) was obtained only between N2O emission rates and NO−3 concentration in soil. However, the degree of explanation was low (R2 = 13%). If one field, with N2O emission rate several orders of magnitude higher than from the others, was excluded from the analysis a significant relation with the NH+4 concentration was obtained. In this case the degree of explanation was 17%. The results from the PLS analysis were similar to those from the regression analysis. If clay soils (>40% clay) were analyzed separately, NH+4 concentration and soil moisture accounted for 65% (P < 0.05) of the variability of the N2O emission rates. In the medium‐ and low‐clay soils no similar relationships were found. In conclusion, the obstacles caused by the complexity of the soil system and the different scales of measurement of N2O emission rates and soil factors probably obscured the possibility to relate the N2O emission rates to single or combinations of soil factors.
Solute Movement through Quartz‐Diorite Saprolite Containing Quartz Veins and Biological Macropores
Authors: Williams J. P. , Vepraskas M. J. 
Published: July 2010

AbstractSaprolite is not permitted for use in on‐site wastewater disposal in North Carolina if quartz veins occur within 60 cm (2 ft) of the septic trench bottom because such features might transmit raw sewage quickly to groundwater. This study evaluated the time of travel (TOT) of a Br− solute through quartz veins in saprolite. Two 150 by 150 cm drainfields were constructed over saprolite containing quartz veins. Following saturation of the saprolite, a Br− tracer and dye were applied for a specific time period. The drainfields were then excavated to 90 cm, the dye pattern mapped, and soil samples collected for Br− analysis. There was no signilicant difference (α = 0.10) in depth of Br− penetration in saprolite with and without quartz veins. On the other hand, mean depth of Br− penetration increased from 14 cm for saprolite without macropores to 40 cm in saprolite with macropores (root channels) that extended to depths between 40 to 90 cm. A simple time of travel model predicted maximum depth of solute movement accurately where macropores were not present. To improve predictions for macropores, effective saturated hydraulic conductivities for saprolite with and without macropores were calculated and then used to estimate different rates of solute movement through saprolite when macropores were and were not present.
Nitrous Oxide Flux from Poultry‐Manured Erosion Plots and Grass Filters after Simulated Rain
Authors: Coyne M. S. , Gilfillen R. A. , Blevins R. L. 
Published: July 2010

AbstractAdding carbon‐rich materials to fields, like manure, may enhance denitrification. Grass filters, which are used to trap surface runoff from these fields, may also provide a carbon‐rich environment that favors water infiltration and denitrification. Nitrous oxide (N2O) may be evolved these settings. It is a radiatively important trace gas and intermediate in the denitrification pathway and several other microbial processes. We measured N2O flux, after simulated rain, using a soil cover technique in poultry‐manured plots and grass filters receiving their runoff. Intact soil cores were used to relate the N2O flux to the denitrification potential of the plots. Nitrous oxide fluxes were smaller in grass filters than in manured plots, even though more denitrifying bacteria were present. The average N2O flux in the three most dynamic erosion plots was 755 µg N2O‐N m−2h−1, which was 39% of the maximal denitrification rate measured in acetylene‐blocked, NO−3‐amended soil cores. Nitrous oxide flux immediately after rainfall was greater than N2O flux measurements reported for similar agricultural settings.
Factors Controlling Throughfall Characteristics at a High Elevation Sierra Nevada Site, California
Authors: Brown Aaron D. , Lund L. J. 
Published: July 2010

AbstractThe composition of throughfall (TF) is influenced by wet and dry deposition on foliar surfaces and by chemical and biological interactions between rain and the foliage. The relative importance of these processes was investigated for TF collected in the summer months of 1985, 1986, and 1987 under three subalpine species, chinquapin (Chrysolepis sempervirens Hjelmqvist), western white pine (Pinus monticola Dougl.), and willow (Salix orestera Schneider), in the Emerald Lake Watershed, Sequoia National Park, California. The depth of rain and days since the last storm were used to predict net‐TF deposition in a multiple linear regression model. Dry deposition to needle surfaces had the greatest influence on western white pine TF composition. Net‐TF data for this species were used to estimate mean dry deposition rates for the summer. These data show that NH+4, NO−3, and SO2−4 dry deposition rates exceed median summer wet deposition rates by 1.5, 1.9, and 1.0 times, respectively. Willow foliage had the greatest influence on TF composition and western white pine the least. Estimated foliar release of cations and organic anions by willow during summer rain is a substantial fraction of annual wet deposition of those ions. Weak organic acid anions derived from foliar release are a significant component of net‐TF in all three species, particularly willow, where summer fluxes of organic acids were at least 51% of the total estimated annual wet deposition of organic anions.
Attainment and Effects Issues Regarding Alternative Secondary Ozone Air Quality Standards
Authors: Lee E. Henry , Hogsett William E. , Tingey David T. 
Published: July 2010

AbstractThe present secondary National Ambient Air Quality Standard (NAAQS) for O3, established in 1979, is based on limited information from a few field studies on vegetation and may not be protective of crop damage due to O3, alone or in combination with other pollutants. Considerable information from field studies conducted in the past decade indicate that there is poor functional correspondence between agricultural production and the air quality index of the current secondary NAAQS for O3. Because the current O3 NAAQS is based on data for extreme values of air quality, the index (or form) of the NAAQS ignores key features of hourly exposure data that are desirable and important to minimizing the risk of crop damage. Previous analyses of existing vegetation effects data indicate that exposure indices that cumulated the hourly O3 concentrations over the season, as well as preferentially weighted the higher concentrations appear to have major advantages over the mean and peak indices on the basis of statistical fits to the data. The peak‐weighted, cumulative indicators whose form and level are determined from crop studies were found useful in achieving a target production level that is higher than that of the current O3 NAAQS indicator with fewer violations. These alternative air quality indicators compare favorably with the current O3 NAAQS in terms of protection against adverse welfare effects and air quality properties to better identify areas having adequate air quality.
Ozone and Carbon Dioxide Effects on Spider Mites in White Clover and Peanut
Authors: Heagle A. S. , Brandenburg R. L. , Burns J. C. , Miller J. E. 
Published: July 2010

AbstractEffects of O3 and/or elevated CO2 on two‐spotted spider mites (Tetranychus urticae Koch) grown on an O3‐sensitive and an O3‐resistant clone of white clover (Trifolium repens L.) were measured in greenhouse and field experiments. Peanut (Arachis hypogeae L.) ‘NC‐9’ was used in one greenhouse study with O3. In field studies, O3 treatments were charcoal filtered air (CF), nonfiltered air (NF), and two NF treatments with O3 added for 12 h d−1 at proportions of ≈ 1.25 and 1.50 times the ambient O3 concentration. In greenhouse studies, constant amounts of O3 were added to CF for 6 h d−1 to achieve mean concentrations ranging from 5 to 100 nL L−1. For the greenhouse O3 × CO2 experiment, CO2 concentrations were ambient and approximately twice‐ambient for 24 h d−1. Plants were exposed to O3 and/or CO2 for ≈7 d before infestation with mites; daily exposures continued for 14 to 28 d to allow reproduction for at least two generations. Leaves were sampled to count eggs, larvae, nymphs, and adults. Ozone caused more chlorosis and necrosis on the O3‐sensitive clover clone (NC‐S) than on the O3‐resistant clone (NC‐R). Carbon dioxide enrichment increased shoot growth of both clones by ≈33%. Statistical analyses indicated significant O3 effects in some experiments and nonsignificant O3 effects in others. A trend toward increased mite populations with increased O3 occurred, however, on NC‐S in all trials. No consistent trends occurred with NC‐R. With peanut, a significant linear increase in mite population occurred with increased O3. Carbon dioxide enrichment increased the rate of population increase on both clover clones, but more so on NC‐R. At 22 to 28 d after infestation, the total population in the twice‐ambient CO2 treatment was 65% greater than in the ambient treatment for NC‐R and 22% greater than in the ambient treatment for NC‐S. There were no statistically significant interactive effects between CO2 and O3 on mite population growth. The apparent clone effects on mite population response to O3 and CO2 strongly suggest that responses were mediated through the host plants.
Clinoptilolite Zeolite Influence on Nitrate Leaching and Nitrogen Use Efficiency in Simulated Sand Based Golf Greens
Authors: Huang Z. T. , Petrovic A. M. 
Published: July 2010

AbstractThe trend in golf greens construction during the past three decades has been towards putting greens with at least 90% sand and limited amounts of silt, clay, or organic matter. High sand based systems typically have low cation‐exchange capacity (CEC) and large saturated hydraulic conductivities (>30 cm h−1), thus, are prone to NO−3 leaching and possibly contribute to ground or surface water contamination. Clinoptilolite zeolite (CZ) has a high CEC (160 cmol kg−1), a large affinity for NH+4 ions and water molecules that may reduce N leaching on sand based putting greens. The impact of CZ amendment of sand putting greens on N leaching and N uptake by creeping bentgrass (Agrostis stolonifera L.) was determined. The lysimeter method was used for growing creeping bentgrass in the greenhouse to determine NO−3 and NH+4 leaching potential and fertilizer N use efficiency. Four N levels (0, 98, 196, and 293 kg NH+4‐N ha−1) and two media, sand‐CZ mix (9:1, w/w), and unamended sand, were included as treatments. Sand plus CZ had a lowered concentration of NO−3 and NH+4 in leachate while doubling the water retention capacity and increasing CEC 200 fold. The greatest reduction of N leaching was found from lysimeters amended with CZ at the highest N rate. Nitrate and NH+4 leaching was 86 and 99% lower, respectively, than the unamended sand lysimeters. The N fertilizer use efficiency was improved by 16 to 22% with the addition of CZ to sand, depending on N application rate. Amendment of sandy rooting media with clinoptilolite promoted better fertilizer N uptake efficiency and reduced N leaching from a highly leachable soil.
Plutonium‐239 + 240 and Americium‐241 in Soils East of Rocky Flats, Colorado
Authors: Litaor M. Iggy , Thompson M. L. , Barth G. R. , Molzer P. C. 
Published: July 2010

AbstractSoils east of the Rocky Flats (RF) near Golden, CO, were contaminated with Pu‐239 + 240 and Am‐241 as a result of past waste‐storage practices. The physicochemical parameters that govern the actinides distribution in the soil are poorly understood. Twenty‐six soil pits at various distances and directions from a contaminated site at RF were excavated, sampled, and analyzed for actinide activities as well as selected physical, chemical, and mineralogical attributes. Plutonium‐239 + 240 and Am‐241 activities in the soils ranged from 164 280 Bq/kg to 0.0037 Bq/kg, decreasing with distance from the source. More than 90% of the Pu‐239 + 240 and Am‐241 activities were confined to the upper 12 cm of the soil, regardless of the soil characteristics, or distance and direction from the source. Evidence of preferential transport in macropores formed along decayed root channels was observed in four soil pits and had translocated Pu‐239 + 240 to a depth of 90 cm. This transport mechanism increased by a factor of 30 the level of Pu‐239 + 240 activity at this depth. Earthworm activity is probably important in the redistribution of actinides in the upper 40 cm of many of the soils investigated. Planning of future remedial activities at RF should consider the findings of this contaminant‐transport study.
The Effect of Technetium‐99 and Environmental Conditions on Soybean Physiology
Authors: Degenkolb Stephanie J. , Neel James W. , Papin Patrick J. 
Published: July 2010

AbstractTechnetium‐99 is considered a long‐term risk of nuclear energy because it has a long half‐life, mass 99 is produced at a high yield during nuclear fission, and Tc‐99 is taken up readily by aquatic and terrestrial organisms. Plants are an important intermediate of Tc‐99 food chain transfer to animals and humans. The present study investigated adenosine triphosphate (ATP), photosynthesis and structural responses of intact soybean seedlings [Glycine max (L.) Merr. cv. Williams] to micromolar amounts of Tc‐99 under different ambient light levels. Adenosine triphosphate was measured directly in primary leaf extract after 6 d of exposure to Tc at varying concentrations (up to 5 µM Tc‐99). The results indicated that under full light conditions (320 µmol photon m−2 s−1), soybean primary leaves contained nanomolar concentrations of ATP almost twice as high as for untreated plants. With a reduction of light intensity by 50%, primary leaf pertechnetate uptake and leaf ATP content were reduced regardless of Tc‐99 exposure levels. Gas exchange measurements with a Li‐Cor 6200 Portable Photosynthesis system indicated a significant decline of photosynthetic rate and a higher internal CO2 accumulation under full light conditions, while stomatal conductance decreased as a function of Tc‐99 concentration. Several possible mechanisms of Tc interaction with chloroplast ultrastructure are proposed. A hypothesis related to the metabolic behavior of Tc in higher plants is presented.