bluuebunny/crossref_metadata_2025_split huggingface dataset:
Measuring Sorption of Hydrophilic Organic Compounds in Soils by an Unsaturated Transient Flow Method
Authors: Ahmad Riaz , Katou Hidetaka , Kookana Rai S. 
Published: May 2005

ABSTRACTDetermination of sorption of hydrophilic, weakly sorbing organic compounds in soil by conventional batch methods using a slurried suspension is often prone to considerable errors because small changes in the solution concentration on equilibration must be accurately determined. This difficulty is exacerbated for compounds susceptible to degradation, which also decreases the solution concentration. The objective of this study was to determine sorption of hydrophilic pesticides by applying an unsaturated transient flow method, which enables determination of sorption at sufficiently small solution to soil ratios. The method makes use of piston‐like displacement of the antecedent solution in equilibrium with sorbed phase when pesticide‐free water is infiltrated into a soil column spiked with a pesticide. Pesticide sorption and the solution concentration are inferred from a plot of total pesticide content per unit mass of soil vs. water content in a region where the antecedent solution is accumulated. Thus, extraction of solution from relative dry soil is unnecessary. We tested this method for two hydrophilic pesticides, monocrotophos [dimethyl (E)‐1‐methyl‐2‐(methyl‐carbamoyl) vinyl phosphate] and dichlorvos (2,2‐dichlorovinyl dimethyl phosphate). The sorption coefficient, Kd, obtained for monocrotophos was slightly lower than that by batch method (Kd = 0.10 vs. 0.19 L kg−1), whereas for dichlorvos, a compound highly susceptible to degradation, the unsaturated flow method yielded a much smaller Kd (0.19 vs. 3.22 L kg−1). The Kd values for both compounds were consistent with the observed retardation in the pesticide displacement in the columns. The proposed method is more representative of field conditions and particularly suitable for weakly sorbing organic compounds in soils.
Assessment of Ambient Ozone Effects on Vegetation Using Snap Bean as a Bioindicator Species
Authors: Burkey Kent O. , Miller Joseph E. , Fiscus Edwin L. 
Published: May 2005

ABSTRACTTropospheric ozone is an air pollutant that is toxic to plants, causing visible injury to foliage and a reduction in growth and yield. The use of plant bioindicators is one approach to assess the ozone impacts in diverse geographical areas. The objective of this study was to evaluate snap bean (Phaseolus vulgaris L.) as a potential bioindicator species. Three snap bean genotypes known to exhibit a range of ozone sensitivity were grown in pots under charcoal‐filtered (CF) or nonfiltered (NF) treatments in open‐top chambers, or under ambient air (AA) conditions. Treatment effects on biomass were not significant at 56 days after planting (DAP), but midseason foliar injury increased in the NF and AA treatments relative to CF controls. An increase in ozone from 25 to 30 nL L−1 in CF controls to approximately 50 nL L−1 in the NF and AA treatments was found to suppress final pod dry weight per plant by 40 to 60% in the most sensitive genotype S156. The same treatments suppressed final pod dry weight by 20 to 30% in a moderately sensitive genotype Oregon‐91, and by 10% or less in a tolerant genotype R123. An S156 to R123 yield ratio of approximately one was observed under CF conditions. The S156 to R123 yield ratio declined to 0.6 to 0.7 in the NF treatment and declined further to 0.4 to 0.5 in the AA treatment, suggesting that ozone impact was underestimated in the open‐top chambers. The results suggest that a snap bean bioindicator system has the potential to detect ambient ozone effects at present‐day ozone concentrations.
Nitrogen Removal in Laboratory Model Leachfields with Organic‐Rich Layers
Authors: Bedessem Marjorie E. , Edgar Thomas V. , Roll Robert 
Published: May 2005

ABSTRACTSeptic system leachfields can release dissolved nitrogen in the form of nitrate into ground water, presenting a significant source of pollution. Low cost, passive modifications, which increase N removal in traditional leachfields, could substantially reduce the overall impact on ground water resources. Bench‐scale laboratory models were constructed to evaluate the effect of placing an organic layer below the leachfield on total N removal. The organic layer provides a carbon source for denitrification. Column units representing septic leachfields were constructed with sawdust–native soil organic layers placed 0.45 m below the influent line and with thicknesses of 0.0, 0.3, 0.6, and 0.9 m. Using a synthetic septic tank effluent, NO3–N concentrations at 3.8 m below the influent line were consistently below 1 mg L−1 during 10 months of operation compared with a NO3–N concentration of nearly 12 mg L−1 in the control column. The average total N removal increased from 31% without the organic layer to 67% with the organic layer. Total N removal appeared limited by the extent of organic N oxidation and nitrification in the 0.45‐m aerobic zone. Design modifications targeted at improving nitrification above the organic layer may further increase total N removal. Increased organic layer thicknesses from 0.3 m to 0.9 m did not significantly improve average total N removal, but caused a shift in residual nitrogen from organic N to ammonia N. Results indicate that addition of a layer of carbon source material at least 0.3 m thick below a standard leachfield substantially improves total N removal.
Effect of Water Table on Willows Grown in Amended Mine Tailing
Authors: Bourret M. M. , Brummer J. E. , Leininger W. C. , Heil D. M. 
Published: May 2005

ABSTRACTSurvival and growth characteristics of two montane riparian willow species, Geyer willow (Salix geyeriana Andersson) and mountain willow (Salix monticola Bebb), grown in amended fluvial mine tailing were investigated in a greenhouse study. Willow stem cuttings were planted in lysimeters that simulated a 60‐cm amended tailing profile with three static water depths (20, 40, and 60 cm) and a fluctuating water table for a total of four water table treatments. Species and water table treatments affected plant biomass and chemical composition of the soil and plant tissue. Mountain willow leaf, stem, and root biomass were 62, 95, and 164% greater, respectively, than for Geyer willow. Averaging across species, the fluctuating water table negatively affected leaf and stem biomass compared with the 20‐ and 60‐cm water table treatments. Manganese was the only metal in plant tissue to strongly respond to water table treatments. Manganese concentrations in mountain willow leaf tissue were approximately twofold higher in the two most saturated water table treatments (20 cm and fluctuating) than in the least saturated water table treatment (60 cm). This trend was consistent with chemical analyses of the growth media, which reflected higher bioavailable Mn in the saturated tailing profile compared with the unsaturated profile. Results from this study indicate that mountain willow is a more vigorous and possibly more metal‐tolerant species than Geyer willow when grown in amended mine tailing and that a fluctuating water table negatively affects willow growth.
Decrease in Water‐Soluble 17β‐Estradiol and Testosterone in Composted Poultry Manure with Time
Authors: Hakk Heldur , Millner Patricia , Larsen Gerald 
Published: May 2005

ABSTRACTLittle attention has been paid to the environmental fate of the hormones 17β‐estradiol and testosterone excreted in animal waste. Land application of manure has a considerable potential to affect the environment with these endocrine disrupting compounds (EDCs). Composting is known to decompose organic matter to a stable, humus‐like material. The goal of the present study was to quantitatively assess levels of water‐soluble 17β‐estradiol and testosterone in composting chicken manure with time. Chicken layer manure was mixed with hay, straw, decomposed leaves, and starter compost, adjusted to approximately 60% moisture, and placed into a windrow. A clay‐amended windrow was also prepared. Windrows were turned weekly, and temperature, oxygen, and CO2 in the composting mass were monitored for either 133 or 139 d. Commercial enzyme immunoassay kits were used to quantitate the levels of 17β‐estradiol and testosterone in aqueous sample extracts. Water‐soluble quantities of both hormones diminished during composting. The decrease in 17β‐estradiol followed first‐order kinetics, with a rate constant k = −0.010/d. Testosterone levels declined at a slightly higher rate than 17β‐estradiol (i.e., k = −0.015/d). Both hormones could still be measured in aqueous extracts of compost sampled at the conclusion of composting. The decline in water‐soluble 17β‐estradiol and testosterone in extracts of clay‐amended compost was not statistically different from normal compost. These data suggest that composting may be an environmentally friendly technology suitable for reducing, but not eliminating, the concentrations of these endocrine disrupting hormones at concentrated animal operation facilities.
Phosphate Adsorption by Ferrihydrite‐Amended Soils
Authors: Rhoton F. E. , Bigham J. M. 
Published: May 2005

ABSTRACTNew technology and approaches for reducing P in runoff from high sediment yield areas are essential due to implementation of increasingly rigorous water quality standards. The objectives of this research were to characterize ferrihydrite (Fe5HO8·4H2O) in terms of its ability to adsorb P from soil solutions and relate its P adsorptive capacity to several soil properties that influence P mobility. A naturally occurring ferrihydrite, collected as an Fe oxide sludge by‐product from a water treatment facility, was equilibrated with soil samples at equivalent rates of 0, 0.34, 3.36, 16.80, and 33.60 Mg ha−1for a 60‐d period. Individual 2‐g subsamples of each soil were then equilibrated with 0, 5, 10, 20, and 40 mg kg−1P in 20 mL of 0.01MCaCl2on a reciprocating shaker for 24 h. After 24 h, P in solution was measured by colorimetric methods, and designated as final P concentrations. The data indicated that the unamended soils with a pH of <6.0 adsorbed, in some cases, 50 times more P than soils with a pH of >7.0. The final P concentrations, averaged for all initial P concentrations and ferrihydrite rates, ranged from 0.09 to 4.63 mg kg−1, and were most highly correlated with pH (r= 0.844;P≤ 0.01), oxalate‐extractable Fe (r= −0.699;P≤ 0.10), and dithionite‐extractable Fe (r= −0.639;P≤ 0.10) contents of the unamended soils. In terms of individual soils, correlation coefficients (r) for final P concentrations versus ferrihydrite amendment rates indicated a statistically significant (P≤ 0.001) negative relationship at all initial P concentrations for most A horizons. Thervalues for the high Fe oxide content B horizon soils did not show a statistically significant response to ferrihydrite additions. The results indicate that P adsorption, in soils amended with ferrihydrite, will be greatest under acid pH conditions below the ferrihydrite zero point of charge (pH 5.77), and low incipient Fe oxide contents.
Quantifying Ground Water Inputs along the Lower Jordan River
Authors: Holtzman Ran , Shavit Uri , Segal‐Rozenhaimer Michal , Gavrieli Ittai , Marei Amer , Farber Efrat , Vengosh Avner 
Published: May 2005

ABSTRACTThe flow rate of the Lower Jordan River has changed dramatically during the second half of the 20th century. The diversion of its major natural sources reduced its flow rate and led to drying events during the drought years of 2000 and 2001. Under these conditions of low flow rates, the potential influence of external sources on the river discharge and chemical composition became significant. Our measurements show that the concentrations of chloride, calcium, and sodium in the river water decrease along the first 20‐km section, while sulfate and magnesium concentrations increase. These variations were addressed by a recent geochemical study, suggesting that ground water inflow plays a major role. To further examine the role of ground water, we applied mass‐balance calculations, using detailed flow rate measurements, water samplings, and chemical analyses along the northern (upstream) part of the river. Our flow‐rate measurements showed that the river base‐flow during 2000 and 2001 was 500 to 1100 L s−1, which is about 40 times lower than the historical flow rates. Our measurements and calculations indicate that ground water input was 20 to 80% of the river water flow, and 20 to 50% of its solute mass flow. This study independently identifies the composition of possible end‐members. These end‐members contain high sulfate concentration and have similar chemical characteristics as were found in agricultural drains and in the “saline” Yarmouk River. Future regional development plans that include the river flow rate and chemistry should consider the interactions between the river and its shallow ground water system.
Evaluation of Soils for Use as Liner Materials: A Soil Chemistry Approach
Authors: DeSutter Tom M. , Pierzynski Gary M. 
Published: May 2005

ABSTRACTMovement of NH4+ below animal waste lagoons is generally a function of the whole‐lagoon seepage rate, soil mineralogy, cations in the lagoon liquor, and selectivity for NH4+ on the soil‐exchange sites. Binary exchange reactions (Ca2+–K+, Ca2+–NH4+, and K+–NH4+) were conducted on two soils from the Great Plains and with combinations of these soils with bentonite or zeolite added. Binary exchanges were used to predict ternary exchanges Ca2+–K+–NH4+ following the Rothmund–Kornfeld approach and Gaines–Thomas convention. Potassium and NH4+ were preferred over Ca2+, and K+ was preferred over NH4+ in all soils and soils with amendments. Generally, the addition of bentonite did not change cation selectivity over the native soils, whereas the addition of zeolite did. The Rothmund–Kornfeld approach worked well for predicting equivalent fractions of cations on the exchanger phase when only ternary‐solution phase compositions were known. Actual swine‐ and cattle‐lagoon solution compositions and the Rothmund–Kornfeld approach were used to project that native soils are predicted to retain 53 and 23%, respectively, of the downward‐moving NH4+ on their exchange sites. Additions of bentonite or zeolite to soils under swine lagoons may only slightly improve the equivalent fraction of NH4+ on the exchange sites. Although additions of bentonite or zeolite may not help increase the NH4+ selectivity of a liner material, increases in the overall cation exchange capacity (CEC) of a soil will ultimately decrease the amount of soil needed to adsorb downward‐moving NH4+
Rapid Manganese Removal from Mine Waters Using an Aerated Packed‐Bed Bioreactor
Authors: Johnson Karen L. , Younger Paul L. 
Published: May 2005

ABSTRACTIn the UK, the Environmental Quality Standard for manganese has recently been lowered to 30 μg/L (annual average), which is less than the UK Drinking Water Inspectorate's Maximum Permitted Concentration Value (50 μg/L). Current passive treatment systems for manganese removal operate as open‐air gravel‐bed filters, designed to maximize either influent light and/or dissolved oxygen. This requires large areas of land. A novel enhanced bioremediation treatment system for manganese removal has been developed that consists of a passively aerated subsurface gravel bed. The provision of air at depth and the use of catalytic substrates help overcome the slow kinetics usually associated with manganese oxidation. With a residence time of only 8 h and an influent manganese concentration of approximately 20 mg/L, >95% of the manganese was removed. The treatment system also operates successfully at temperatures as low as 4°C and in total darkness. These observations have positive implications for manganese treatment using this technique in both colder climates and where large areas of land are unavailable. Furthermore, as the operation of this passive treatment system continually generates fresh manganese oxyhydroxide, which is a powerful sorbent for most pollutant metals, it potentially has major ancillary benefits as a removal process for other metals, such as zinc.
A Thermodynamically Based Method to Quantify True Sorption Hysteresis
Authors: Sander Michael , Lu Yuefeng , Pignatello Joseph J. 
Published: May 2005

ABSTRACTSorption of organic chemicals to soils and sediments often shows true hysteresis (i.e., nonsingularity of the sorption–desorption isotherm not attributable to known experimental artifacts). Since true sorption hysteresis is fundamentally important to contaminant fate, a way to quantify it is desirable. Previously proposed indices of hysteresis are empirical and usually depend on the isotherm model. True sorption hysteresis to synthetic and natural organic solids has been attributed to irreversible alteration of the solid during the sorption–desorption cycle. Given this mechanism, we propose the Thermodynamic Index of Irreversibility (TII) for quantifying hysteresis in soils where natural organic matter dominates the sorption process. The TII is based on the difference in free energy between the real desorption state and the hypothetical fully reversible state. The index is 0 for completely reversible systems and approaches 1 as the process tends toward complete irreversibility. It does not require any assumptions about the physical properties or molecular composition of the solid, and it does not depend on a specific equilibrium model. A sensitivity analysis of measurement errors provides general recommendations for the setup of sorption–desorption experiments. The TII was applied to sorption of 1,4‐dichlorobenzene (DCB) to two high‐organic soils, Pahokee peat (PP) and Amherst soil (AS), and a low‐rank coal reference material, Beulah‐Zap lignite (BZL). Common artificial causes of hysteresis were eliminated. Hysteresis was significant in the peat and the coal. The TII was clearly concentration dependent for both solids; it decreased with concentration for the peat, but increased with concentration for the coal. The TII allows quantification of hysteresis as a function of sorbate–sorbent combination, concentration, time, and other variables.
Phosphorus Extractability of Soils Amended with Stockpiled and Composted Cattle Manure
Authors: Schwartz R. C. , Dao T. H. 
Published: May 2005

ABSTRACTManaging fertilizer applications to maintain soil P below environmentally unacceptable levels should consider the contribution of manure and synthetic fertilizer sources to soluble and extractable forms of P. Our objective was to evaluate soil and manure characteristics and application rates on P extractability in recently amended soils. Five soils of the U.S. southern High Plains were amended with beef cattle manures, composted beef manure, and inorganic fertilizers [Ca(H2PO4)2or KH2PO4] at five rates and incubated under controlled conditions. Mehlich 3–, Olsen (NaHCO3)–, Texas A&M extractant (TAM)–, and water‐extractable P were determined for the soils after selected incubation periods. Except for TAM and some water extractions, P extractability as a function of total P applied was linear (P< 0.001) for a wide range of application rates. Mehlich‐3, NaHCO3, and water P extraction efficiencies of KH2PO4–amended soils averaged 22, 34, and 115% greater (P≤ 0.036), respectively, than efficiencies of soils amended with manures except for the Texline (calcareous) loam and Pullman clay loam soils. Phosphorus extraction efficiencies decreased with time for KH2PO4–amended soils (P< 0.05) but remained stable or increased for manure‐amended soils during the 8‐wk incubation period. Across all soils and manure sources, changes in water‐extractable P per unit increase in Mehlich 3–, NaHCO3–, and TAM‐extractable P averaged 100, 85, and 125% greater, respectively, for inorganic as compared with manure‐amended soils. These source‐dependent relationships limit the use of agronomic soil extractants to make correct inferences about water‐extractable P and dissolved P in runoff.
Persistence of Testosterone and 17β‐Estradiol in Soils Receiving Swine Manure or Municipal Biosolids
Authors: Jacobsen Anne‐Marie , Lorenzen Angela , Chapman Ralph , Topp Edward 
Published: May 2005

ABSTRACTNatural and synthetic steroidal hormones can be carried to agricultural soil through fertilization with municipal biosolids, livestock manure, or poultry manure. The persistence and pathways of dissipation of [4–14C]‐testosterone and of [4–14C]‐17β‐estradiol in organic‐amended soils were investigated using laboratory microcosms. Testosterone dissipation was investigated over a range of amendment concentrations, temperatures, and soil types. Under all conditions the parent compound and transformation products were dissipated within a few days. Addition of swine manure slurry to soil hastened the transformation of testosterone and 17β‐estradiol to the corresponding less hormonally active ketones, 4‐androstene‐3,17‐dione and estrone. Two other testosterone transformation products, 5α‐androstan‐3,17‐dione and 1,4‐androstadiene‐3,17‐dione, were also detected. Experiments with sterilized soil and sterilized swine manure slurry suggested that the transformation of 14C‐labeled hormonal parent compounds was mainly caused by microorganisms in manure slurry, while mineralization of the hormones to 14CO2 required viable soil microorganisms. Organic amendments transiently inhibited the mineralization of [4–14C]‐testosterone, perhaps by inhibiting soil microorganisms, or by enhancing sorption and reducing the bioavailability of testosterone or transformation products. Overall, organic amendments influenced the pathways and kinetics of testosterone and estradiol dissipation, but did not increase their persistence.
Proton Binding by Humic and Fulvic Acids from Pig Slurry and Amended Soils
Authors: Plaza César , García‐Gil Juan C. , Polo Alfredo , Senesi Nicola , Brunetti Gennaro 
Published: May 2005

ABSTRACTThe knowledge of acid–base characteristics of humic acid (HA) and fulvic acid (FA) fractions of organic amendments and amended soils is of considerable importance for assessing their agronomic efficacy and environmental impact. In this work, the acid–base properties of HAs and FAs isolated from pig slurry, soils amended with either 90 or 150 m3 ha−1 yr−1 of pig slurry for 3 yr, and the corresponding nonamended control soil were investigated by using a current potentiometric titration method. The nonideal competitive adsorption (NICA) model that describes proton binding by two classes of binding sites (carboxylic‐ and phenolic‐type groups) was successfully fit to titration data. With respect to the control soil HA and FA, pig‐slurry HA and FA were generally characterized by smaller carboxylic‐type group contents, slightly smaller phenolic‐type group contents, larger affinities for proton binding by the carboxylic‐type groups, and much smaller, in the case of the HA fraction, or similar, in the case of the FA fraction, affinities for proton binding by the phenolic‐type groups. Amendment with pig slurry determined a number of modifications in soil HAs and FAs, including decrease of acidic functional group contents, and slight increase of the proton affinity of the carboxylic‐type groups. Further, a slight decrease of the affinities for proton binding by the phenolic‐type groups of HAs was observed. These effects can have a large impact on the biological availability, mobilization, and transport of macro‐ and micronutrients, toxic metal ions, and xenobiotic organic cations in pig slurry–amended soils.