bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Flow Rate on Transport of Bacteriophage in Shale Saprolite
Authors: McKay L.D. , Harton A.D. , Wilson G.V.
Published: June 2010

The objective of this study was to investigate the influence of flow rate on transport and retention of bacteriophage tracers in a fractured shale saprolite, which is a highly weathered, fine‐grained subsoil that retains much of the fabric of the parent bedrock. Synthetic ground water containing PRD‐1, MS‐2, and bromide was passed through a saturated column of undisturbed shale saprolite at rates ranging from 0.0075 to 0.96 m d−1 First arrival of the bacteriophage tracers in effluent samples in each of the experiments occurred within 0.01 to 0.04 pore volumes (PV) of the start of injection, indicating that bacteriophage were advectively transported mainly through fractures or macropores. Bacteriophage transport velocities, based on first arrival in the effluent, were very similar to fracture flow velocities calculated using the cubic law for flow in a fractured material. For MS‐2, maximum concentration and mass of tracer recovered both increased steadily as flow rate increased. For PRD‐1, these values initially increased, but were nearly constant at flow rates above 0.039 m d−1, indicating that approximately 50% of the observed losses were independent of flow rate. Evaluation of the data indicates that physical straining and electrostatic or hydrophobic attachment to fracture or macropore walls were the dominant retention processes. Inactivation and gravitational settling playing secondary roles, except at the slowest flow rates. The study suggests that microbial contamination from sources such as septic fields and sewage ponds may pose a threat to the quality of ground water and surface water in areas with saprolitic subsoils.
Influence of Manure Application on Surface Energy and Snow Cover
Authors: Kongoli C. E. , Bland W. L.
Published: June 2010

Application of manure to frozen and/or snow‐covered soils of high‐latitude, continental climate regions is associated with enhanced P losses to surface water bodies, but the practice is an essential part of most animal farming systems in these regions. Field experiments of the fates of winter‐applied manure P are so difficult as to make them essentially impractical, so a mechanistic, modeling approach is required. Central to a mechanistic understanding of manure P snowmelt runoff is knowledge of snowpack disappearance (ablation) as affected by manure application. The objective of this study was to learn how solid manure applied to snow‐covered fields modulates the surface energy balance and thereby snow cover ablation. Manure landspreading experiments were conducted in Arlington, WI during the winters of 1998 and 1999. Solid dairy manure was applied on top of snow at a rate of 70 Mg ha−1 in 1998, and at 45 and 100 Mg ha−1 in 1999. Results showed that the manure retarded melt, in proportion to the rate applied. The low‐albedo manure increased absorption of shortwave radiation compared with snow, but this extra energy was lost in longwave radiation and turbulent flux of sensible and latent heat. These losses result in significant attenuation of melt peaks, retarding snowmelt. Lower snowmelt rates beneath manure may allow more infiltration of meltwater compared with bare snow. This infiltration and attenuated snowmelt runoff may partially mitigate the enhanced likelihood of P runoff from unincorporated winter‐spread manure.
Modeling Atmospheric Nitrogen Deposition and Transport in the Chesapeake Bay Watershed
Authors: Sheeder Scott A. , Lynch James A. , Grimm Jeffrey
Published: June 2010

Atmospheric deposition of nitrate nitrogen and ammonium nitrogen has been identified as a major factor in the decline of water quality in the Chesapeake Bay. Reports have indicated that atmospheric deposition may account for 25 to 80% of the total nitrogen load entering the bay. However, uncertainties exist regarding the accuracy of the atmospheric deposition inputs, nitrogen retention coefficients, and in‐stream nutrient uptake rates used in these studies. This project was designed to reassess the potential inputs of atmospheric nitrogen deposition to the bay through the use of a high‐resolution wet deposition model, improved wet and dry deposition and nutrient retention estimates, existing soils and land use data, and geographic information systems software. Model results indicate that the methods used in previous studies may overestimate the contribution of atmospheric nitrate and ammonium deposition to the Chesapeake Bay watershed (CBW). Wet and dry atmospheric nitrate and ammonium nitrogen deposition estimates to the CBW ranged from 52.7 to 141.9 and 41.9 to 60.1 million kg/yr, respectively, between 1984 and 1996. Dry and total atmospheric deposition loads to the watershed are substantially less than previous estimates. Estimates of the percent contribution of atmospherically deposited nitrogen to the Chesapeake Bay represent between 20 and 32% of the total nitrate and ammonium nitrogen load to the watershed from all nitrogen sources. While these estimates are lower than many other published estimates, regression analysis of model parameters, nitrogen retention coefficients, output, and measured in‐stream nitrogen loads indicate that the calculated nitrogen loads may still be too high.
Agroforestry Practices, Runoff, and Nutrient Loss
Authors: Udawatta Ranjith P. , Krstansky J. John , Henderson Gray S. , Garrett Harold E.
Published: June 2010

A paired watershed study consisting of agroforestry (trees plus grass buffer strips), contour strips (grass buffer strips), and control treatments with a corn (Zea mays L.)–soybean [Glycine max (L.) Merr.] rotation was used to examine treatment effects on runoff, sediment, and nutrient losses. During the (1991–1997) calibration and subsequent three‐year treatment periods, runoff was measured in 0.91‐ and 1.37‐m H‐flumes with bubbler flow meters. Composite samples were analyzed for sediment, total phosphorus (TP), total nitrogen (TN), nitrate, and ammonium. Calibration equations developed to predict runoff, sediment, and nutrients losses explained 66 to 97% of the variability between treatment watersheds. The contour strip and agroforestry treatments reduced runoff by 10 and 1% during the treatment period. In both treatments, most runoff reductions occurred in the second and third years after treatment establishment. The contour strip treatment reduced erosion by 19% in 1999, while erosion in the agroforestry treatment exceeded the predicted loss. Treatments reduced TP loss by 8 and 17% on contour strip and agroforestry watersheds. Treatments did not result in reductions in TN during the first two years of the treatment period. The contour strip and agroforestry treatments reduced TN loss by 21 and 20%, respectively, during a large precipitation event in the third year. During the third year of treatments, nitrate N loss was reduced 24 and 37% by contour strip and agroforestry treatments. Contour strip and agroforestry management practices effectively reduced nonpoint‐source pollution in runoff from a corn–soybean rotation in the clay pan soils of northeastern Missouri.
An Assessment of Stream Water Quality of the Rio San Juan, Nuevo Leon, Mexico, 1995–1996
Authors: Laureano José Santos Flores , Návar José
Published: June 2010

Good water quality of the Rio San Juan is critical for economic development of northeastern Mexico. However, water quality of the river has rapidly degraded during the last few decades. Societal concerns include indications of contamination problems and increased water diversions for agriculture, residential, and industrial water supplies. Eight sampling sites were selected along the river where water samples were collected monthly for 10 mo (October 1995–July 1996). The concentration of heavy metals and chemical constituents and measurements of bacteriological and physical parameters were determined on water samples. In addition, river discharge was recorded. Constituent concentrations in 18.7% of all samples exceeded at least one water quality standard. In particular, concentrations of fecal and total coliform bacteria, sulfate, detergent, dissolved solids, Al, Ba, Cr, Fe, and Cd, exceeded several water quality standards. Pollution showed spatial and temporal variations and trends. These variations were statistically explained by spatial and temporal changes of constituent inputs and discharge. Samples collected from the site upstream of El Cuchillo reservoir had large constituent concentrations when discharge was small; this reservoir supplies domestic and industrial water to the city of Monterrey.
Long‐Term Studies on the Effects of Nonvolatile Organic Compounds on Porous Media Surface Areas
Authors: Khachikian Crist S. , Harmon Thomas C.
Published: June 2010

This paper investigates the long‐term behavior of porous media contaminated by nonvolatile organic compounds (NVOC) in terms of specific interfacial surface area. Specifically, a natural sand, Moffett sand (MS), was contaminated with naphthalene and the surface area was measured repeatedly over time using nitrogen adsorption–desorption techniques. A field‐contaminated sand affected by lampblack material (LB) from former manufactured gas plant operations was also studied. Lampblack is a carbonaceous skeleton containing polycyclic aromatic hydrocarbons (PAHs) and other hydrocarbons. It is hypothesized that soils contaminated by these types of chemicals will exhibit significantly less surface area than their clean counterparts. The surface areas for the contaminated MS samples increased toward their clean‐MS values during the 700‐h aging period, but achieved the clean values only after pentane extraction or heating at 60°C. Heating at 50°C failed to achieve a similar recovery of the clean‐MS surface area value. Nonspecific mass loss tracked the increase in surface area as indirect evidence that naphthalene loss was the cause of the surface area increase. For the LB samples, aging at 100°C produced a slight decrease in surface area and mass while aging at 250°C caused the surface area to increase roughly threefold while the mass decreased by approximately 1%. These results suggest that, under moderate heating and over the time scale of this investigation, there is a redistribution of the complex contaminant mixture on the solid matrix. Greater temperatures remove mass more efficiently and therefore exhibited the surface area increase expected in this experiment.
Influence of Water Treatment Residuals on Phosphorus Solubility and Leaching
Authors: Elliott H.A. , O'Connor G.A. , Lu P. , Brinton S.
Published: June 2010

Laboratory and greenhouse studies compared the ability of water treatment residuals (WTRs) to alter P solubility and leaching in Immokalee sandy soil (sandy, siliceous, hyperthermic Arenic Alaquod) amended with biosolids and triple superphosphate (TSP). Aluminum sulfate (Al‐WTR) and ferric sulfate (Fe‐WTR) coagulation residuals, a lime softening residual (Ca‐WTR) produced during hardness removal, and pure hematite were examined. In equilibration studies, the ability to reduce soluble P followed the order: Al‐WTR > Ca‐WTR ≈ Fe‐WTR >> hematite. Differences in the P‐fixing capacity of the sesquioxide‐dominated materials (Al‐WTR, Fe‐WTR, hematite) were attributed to their varying reactive Fe‐ and Al‐hydrous oxide contents as measured by oxalate extraction. Leachate P was monitored from greenhouse columns where bahiagrass (Paspalum notatum Flugge) was grown on Immokalee soil amended with biosolids or TSP at an equivalent rate of 224 kg P ha−1 and WTRs at 2.5% (56 Mg ha−1). In the absence of WTRs, 21% of TSP and 11% of Largo cake biosolids total phosphorus (PT) leached over 4 mo. With co‐applied WTRs, losses from TSP columns were reduced to 3.5% (Fe‐WTR), 2.5% (Ca‐WTR), and <1% (Al‐WTR) of applied P. For the Largo biosolids treatments all WTRs retarded downward P flux such that leachate P was not statistically different than for control (soil only) columns. The phosphorus saturation index (PSI = [Pox]/[Alox + Feox], where Pox, Alox, and Feox are oxalate‐extractable P, Al, and Fe, respectively) based on a simple oxalate extraction of the WTR and biosolids is potentially useful for determining WTR application rates for controlled reduction of P in drainage when biosolids are applied to low P‐sorbing soils.
Particulate and Dissolved Phosphorus Chemical Separation and Phosphorus Release from Treated Dairy Manure
Authors: Dao Thanh H. , Daniel Tommy C.
Published: June 2010

In confined animal feeding operations, liquid manure systems present special handling and storage challenges because of the large volume of diluted wastes. Water treatment polymers and mineral phosphorus (P) immobilizing chemicals [Al2(SO4)3·18H2O, FeCl3·6H2O, and Class C fly ash] were used to determine particulate and dissolved reactive phosphorus (DRP) reduction mechanisms in high total suspended solid (TSS) dairy manure and the P release from treated manure and amended soils. Co‐application exceeded the aggregation level achieved with individual manure amendments and resulted in 80 and 90% reduction in metal salt and polymer rates, respectively. At marginally effective polymer rates between 0.01 and 0.25 g L−1, maximal aggregation was attained in combination with 1 and 10 g L−1 of aluminum sulfate (3 and 30 mmol Al3+ L−1) and iron chloride (3.7 and 37 mmol Fe3+ L−1) in 30 g L−1 (TSS30) and 100 g L−1 TSS (TSS100) suspensions, respectively. Fly ash induced particulate destabilization at rates ≥50 g L−1 and reduced solution‐phase DRP at all rates ≥1 g L−1 by 52 and 71% in TSS30 and TSS100 suspensions, respectively. Aluminum and Fe salts also lowered DRP at rates ≤10 g L−1 and higher concentrations redispersed particulates and increased DRP due to increased suspension acidity and electrical conductivity. The DRP release from treated manure solids and a Typic Paleudult amended with treated manure was reduced, although the amendments increased Mehlich 3–extractable P. Therefore, the synergism of flocculant types allowed input reduction in aggregation aid chemicals, enhancing particulate and dissolved P separation and immobilization in high TSS liquid manure.
Accelerated Deployment of an Agricultural Nutrient Management Tool
Authors: Coale Frank J. , Sims J. Thomas , Leytem April B.
Published: June 2010

In 1998, the Maryland legislature mandated nitrogen (N) and phosphorus (P) nutrient management planning for nearly all of Maryland's commercial agricultural operations. State regulations required that a phosphorus indexing tool (P Index) be used for determining the potential for P losses from agricultural land, even though a reliable P Index did not exist. The development and assessment of the P Index as a dependable tool for the evaluation of the potential for P losses was constrained by a very aggressive implementation schedule imposed by state regulations. The Maryland Phosphorus Site Index (PSI) was evaluated on 646 state‐representative field sites beginning in the spring of 1999 and continuing through the spring of 2000. Of the representative fields, 69% were determined to have a “low” P loss rating, 19% were in the “medium” P loss rating category, 8% were determined to be a “high” risk for P loss, and 4% rated as “very high” P loss potential. Fifty‐five percent of the fields evaluated had soil test phosphorus (STP) levels less than the 75 mg kg−1 Mehlich‐1 P environmental threshold established by state regulations. The frequency distribution of PSI performance was evaluated for several subcategories of the statewide data set. The Maryland PSI will be deployed for use in constructing farm nutrient management plans well before its predictive capabilities can be objectively and rigorously validated. Field validation is essential. In the meantime, the Maryland PSI should function adequately as a tool to assist in the prioritization of field P loss risk potential.
Cottongrass Effects on Trace Elements in Submersed Mine Tailings
Authors: Stoltz Eva , Greger Maria
Published: June 2010

Phytostablization may limit the leakage of metals and As from submersed mine tailings, thus treatment of acid mine drainage with lime could be reduced. Tall cottongrass (Eriophorum angustifolium Honckeny) and white cottongrass (E. scheuchzeri Hoppe) were planted in pots with unlimed (pH 5.0) and limed (pH 10.9) tailings (containing sulfides) amended with sewage sludge (SS) or a bioash–sewage sludge mixture (ASM). Effects of the amendments on plant growth and plant element uptake were studied. Also, effects of plant growth on elements (Cd, Cu, Pb, Zn, and As), pH, electrical conductivity (EC), and concentrations of SO2−4, in the drainage water as well as dissolved oxygen in tailings, were measured. Both plant species grew better and the shoot element concentrations of white cottongrass were lower in SS than in ASM. Metal concentrations were lowest in drainage water from limed tailings, and plant establishment had little effect on metal release, except for an increase in Zn levels, even though SO2−4 levels were increased. In unlimed tailings, plant growth increased SO2−4 levels slightly; however, pH was increased and metal concentrations were low. Thus, metals were stabilized by plant uptake and high pH. Amendments or plants did not affect As levels in the drainage water from unlimed tailings. Thus, to reduce the use of lime for stabilizing metals, phytostabilization with tall cottongrass and white cottongrass on tailings is a sound possibility.
Ammonia, Methane, and Nitrous Oxide Emission from Pig Slurry Applied to a Pasture in New Zealand
Authors: Sherlock Robert R. , Sommer Sven G. , Khan Rehmat Z. , Wood C. Wesley , Guertal Elizabeth A. , Freney John R. , Dawson Christopher O. , Cameron Keith C.
Published: June 2010

Much animal manure is being applied to small land areas close to animal confinements, resulting in environmental degradation. This paper reports a study on the emissions of ammonia (NH3), methane (CH4), and nitrous oxide (N2O) from a pasture during a 90‐d period after pig slurry application (60 m3ha−1) to the soil surface. The pig slurry contained 6.1 kg total N m−3, 4.2 kg of total ammoniacal nitrogen (TAN = NH3+ NH4) m−3, and 22.1 kg C m−3, and had a pH of 8.14. Ammonia was lost at a fast rate immediately after slurry application (4.7 kg N ha−1h−1), when the pH and TAN concentration of the surface soil were high, but the loss rate declined quickly thereafter. Total NH3losses from the treated pasture were 57 kg N ha−1(22.5% of the TAN applied). Methane emission was highest (39.6 g C ha−1h−1) immediately after application, as dissolved CH4was released from the slurry. Emissions then continued at a low rate for approximately 7 d, presumably due to metabolism of volatile fatty acids in the anaerobic slurry–treated soil. The net CH4emission was 1052 g C ha−1(0.08% of the carbon applied). Nitrous oxide emission was low for the first 14 d after slurry application, then showed emission peaks of 7.5 g N ha−1h−1on Day 25 and 15.8 g N ha−1h−1on Day 67, and decline depending on rainfall and nitrate (NO3) concentrations. Emission finally reached background levels after approximately 90 d. Nitrous oxide emission was 7.6 kg N ha−1(2.1% of the N applied). It is apparent that of the two major greenhouse gases measured in this study, N2O is by far the more important tropospheric pollutant.
Reclamation of High‐Elevation, Acidic Mine Waste with Organic Amendments and Topsoil
Authors: Sydnor M. E. Winter , Redente E. F.
Published: June 2010

The Summitville Mine was a high‐elevation (3500 m) gold mine in southwestern Colorado. The mine was abandoned in 1992, leaving approximately 200 ha of disturbance comprised partially of an open pit, a cyanide heap leach pad, and two large waste rock piles. Reclamation of these mine facilities is challenging due to extreme climatic conditions in conjunction with high acid‐production potential and low organic matter content of waste materials on site. In addition, stockpiled topsoil at the site is acidic and biologically inactive due to long‐term storage, and may not be suitable for plant growth. The purpose of this study was to evaluate the effects of organic amendments (mushroom compost vs. biosolids) and topsoil (stockpiled vs. nonstockpiled) on aboveground biomass and plant trace element uptake. An on‐site field study was established in 1995 to identify the most effective combination of treatments for successful reclamation of on‐site waste rock materials. Incorporation of organic matter significantly increased aboveground biomass, with mushroom compost being more effective than biosolids, but did not significantly influence trace element uptake. Conversely, the use of topsoil did not affect aboveground biomass, but did influence trace element uptake. Treatments that received topsoil supported plant growth with significantly higher trace element tissue concentrations than treatments that did not receive topsoil. In general, it was found that waste rock could be directly revegetated when properly neutralized, fertilized, and amended with organic matter. Additionally, stockpiled topsoil, when neutralized with lime, supported plant growth equivalent to that on nonstockpiled topsoil.
Kriging Method Evaluation for Assessing the Spatial Distribution of Urban Soil Lead Contamination
Authors: Cattle Julie A. , McBratney Alex. B. , Minasny Budiman
Published: June 2010

Describing contaminant spatial distribution is an integral component of risk assessment. Application of geostatistical techniques for this purpose has been demonstrated previously. These techniques may provide both an estimate of the concentration at a given unsampled location, as well as the probability that the concentration at that location will exceed a critical threshold concentration. This research is a comparative study between multiple indicator kriging and kriging with the cumulative distribution function of order statistics, with both local and global variograms. The aim was to determine which of the four methods is best able to delineate between “contaminated” and “clean” soil. The four methods were validated with a subset of data values that were not used in the prediction. Method performance was assessed by calculating the root mean square error (RMSE), analysis of variance, the proportion of sites misclassified by each method as either “clean” when they were actually “contaminated” or vice versa, and the expected loss for each misclassification type. The data used for the comparison were 807 topsoil Pb concentrations from the inner‐Sydney suburbs of Glebe and Camperdown, Australia. While there was very little difference between the four methods, multiple indicator kriging was found to produce the most accurate predictions for delineating “clean” from “contaminated” soil.
Pesticides in Surface Water, Sediment, and Rainfall of the Northeastern Pantanal Basin, Brazil
Authors: Laabs Volker , Amelung Wulf , Pinto Alicio A. , Wantzen Matthias , da Silva Carolina J. , Zech Wolfgang
Published: June 2010

Within the last 25 years an intensive agriculture has developed in the highland regions of Mato Grosso state (Brazil), which involves frequent pesticide use in highly mechanized cash‐crop cultures. To provide information on pesticide distribution and dynamics in the northeastern Pantanal basin (located in southern Mato Grosso), we monitored 29 pesticides and 3 metabolites in surface water, sediment, and rainwater of the study area during the main application season. In environmental samples, 19 pesticides and 3 metabolites were detected in measurable quantities, resulting in at least one pesticide detection in 68% of surface water samples (n = 139), 62% of sediment samples (n = 26), and 87% of rainwater samples (n = 91). Surface water samples were most frequently contaminated by endosulfan compounds (α‐, β‐, ‐sulfate), ametryn, metolachlor, and metribuzin, although in low (<0.1 μg L−1) concentrations. Sediment samples exhibited concentrations up to 4.5 μg kg−1 of p,p′‐DDT, p,p′‐DDE, endosulfan‐sulfate, β‐endosulfan, and ametryn. In contrast, rainwater was polluted with substantial amounts of endosulfan, alachlor, metolachlor, trifluralin, monocrotofos, and profenofos (maximum concentrations = 0.3 to 2.3 μg L−1) in the highlands. Lowland rainwater samples taken 75 km from the next application area contained 5‐ to 10‐fold lower mean pesticide concentration than in the highlands. Cumulative deposition rates of the pesticide sum within the study period ranged from 423 μg m−2 in the highlands to 14 μg m−2 in the lowlands. The atmospheric input of pesticides to ecosystems seemed to be of higher relevance in the tropical study area than known from temperate regions.
Salmonella typhimurium Survival and Viability is Unaltered by Suspended Particles in Freshwater
Authors: Maki Ryan P. , Hicks Randall E.
Published: June 2010

Rolling microcosm experiments were conducted to determine whether suspended particles affect the survival and viability of a model pathogen, Salmonella choleraesuis, serotype typhimurium (American Type Culture Collection no. 23567), in a freshwater microbial community. Water from the Duluth, MN harbor of Lake Superior (including native microorganisms) was inoculated with clay, silt, or flocculent organic particles in a range of concentrations and a streptomycin‐resistant strain of S. typhimurium Microcosms (incubated at 20°C) were rolled horizontally (3 rpm) and sampled periodically for total bacteria and total, viable, and culturable S. typhimurium Total S. typhimurium abundance decreased rapidly in all experiments (8.5–73.1% d−1). Total bacteria did not decrease as rapidly as the S. typhimurium population in any experiment, suggesting that a microcosm effect was not responsible for the decline in S. typhimurium populations. Loss rates of attached and free cells were similar, indicating that attachment to particles did not enhance the persistence of Salmonella cells beyond our minimum detectable differences. After eight days, only 0.1 to 11.9% of the initial S. typhimurium inocula were detected by direct counts. Suspended particles had a minimal effect on the survival and viability of S. typhimurium; the losses of total, viable, or culturable Salmonella were generally the same across particle treatments and concentrations. Silt and flocculent particles affected loss rates of total and viable S. typhimurium similarly to inorganic particles (clay). It appears unlikely that suspended particles would provide a means for S. typhimurium to persist at hazardous levels in freshwater.
Phosphorus and Nitrate Nitrogen in Runoff Following Fertilizer Application to Turfgrass
Authors: Shuman L. M.
Published: June 2010

Intensively managed golf courses are perceived by the public as possibly adding nutrients to surface waters via surface transport. An experiment was designed to determine the transport of nitrate N and phosphate P from simulated golf course fairways of ‘Tifway’ bermudagrass [Cynodon dactylon (L.) Pers.]. Fertilizer treatments were 10–10–10 granular at three rates and rainfall events were simulated at four intervals after treatment (hours after treatment, HAT). Runoff volume was directly related to simulated rainfall amounts and soil moisture at the time of the event and varied from 24.3 to 43.5% of that added for the 50‐mm events and 3.1 to 27.4% for the 25‐mm events. The highest concentration and mass of phosphorus in runoff was during the first simulated rainfall event at 4 HAT with a dramatic decrease at 24 HAT and subsequent events. Nitrate N concentrations were low in the runoff water (approximately 0.5 mg L−1) for the first three runoff events and highest (approximately 1–1.5 mg L−1) at 168 HAT due to the time elapsed for conversion of ammonia to nitrate. Nitrate N mass was highest at the 4 and 24 HAT events and step‐wise increases with rate were evident at 24 HAT. Total P transported for all events was 15.6 and 13.8% of that added for the two non‐zero rates, respectively. Total nitrate N transported was 1.5 and 0.9% of that added for the two rates, respectively. Results indicate that turfgrass management should include applying minimum amounts of irrigation after fertilizer application and avoiding application before intense rain or when soil is very moist.
Nutrient Processing Capacity of a Constructed Wetland in Western Ireland
Authors: Healy M. , Cawley A. M.
Published: June 2010

In Ireland, constructed wetland systems are increasingly being used to perform tertiary treatment on municipal waste effluent from small towns and villages located in areas whose receiving waters are deemed sensitive. The bedrock formation in the west of Ireland is primarily karst limestone and where the overburden–soil cover is very shallow, such waters are highly sensitive to pollution sources, as little or no natural attenuation and/or treatment will occur. Constructed wetland technology has been seen to offer a relatively low‐cost alternative to the more conventional tertiary treatment technologies, particularly when dealing with low population numbers in small rural communities. This paper examines the waste treatment performance, in terms of nutrient (P and N) reduction, of a recently constructed surface‐flow wetland system at Williamstown, County Galway, Ireland. Performance evaluation is based on more than two years of water quality and hydrological monitoring data. The N and P mass balances for the wetland indicate that the average percentage reduction over the two‐year study period is 51% for total N and 13% for total P. The primary treatment process in the wetland system for suspended solids (between 84 and 90% reduction), biological oxygen demand (BOD) (on average, 49% reduction), N, and P is the physical settlement of the particulates. However, the formation of algal bloom during the growing season reduces the efficiency of the total P removal.
Biodegradation during Contaminant Transport in Porous Media
Authors: Yolcubal Irfan , Pierce Shelley A. , Maier Raina M. , Brusseau Mark L.
Published: June 2010

This study investigated the interaction between microbial growth and cell elution, and their influence on resultant microbial distribution between the aqueous and solid phases during solute transport in a sandy, low‐organic‐carbon‐content porous medium. Miscible displacement experiments were conducted with salicylate as the model compound, and with different initial conditions (e.g., substrate concentrations and cell densities) to attain various degrees of microbial growth. For each experiment, salicylate and dissolved oxygen concentrations as well as cell densities were monitored in the column effluent. Cell densities were also measured in the porous medium at the beginning and end of each experiment. Total microbial growth was determined in two ways, one based on a cell mass balance for the system and the other based on total amount of salicylate degraded. For conditions yielding a considerable amount of microbial growth, the majority of the biomass was associated with the aqueous phase (68–90%). Conversely, under minimal‐growth conditions, most cells (approximately 60–70%) were attached to particle surfaces. Significant cell elution was observed for most conditions, the rate of which increased in the presence of the substrate. The results suggest that the increase in aqueous‐phase cells observed for the experiments exhibiting the greatest growth is associated with the production of new cells, and that under appropriate conditions aqueous‐phase biomass can contribute significantly to contaminant biodegradation.
Polycyclic Aromatic Hydrocarbon Removal from Soil by Surfactant Solubilization and Phanerochaete chrysosporium Oxidation
Authors: Zheng Zhongming , Obbard Jeffrey Philip
Published: June 2010

Surfactant soil washing can remove polycyclic aromatic hydrocarbons (PAHs) from contaminated soil, and the white rot fungus, Phanerochaete chrysosporium Burdsall in Burdsall & Eslyn, can oxidize PAHs. The objective of this study was to develop a novel bioremediation technology using a combination of abiological surfactant soil washing followed by PAH biological oxidation in soil washwater using P. chrysosporium in a rotating biological contactor (RBC) reactor. Soil used for experimentation was an 11‐month aged contaminated soil spiked with a total of nine PAHs: acenaphthene, fluorene, phenanthrene, fluoranthene, pyrene, chrysene, benzo(a)pyrene, dibenz(ah)anthracene, and benzo(ghi)perylene. After 11 months of aging, recovery percentages of high molecular weight PAHs [i.e., from chrysene to benzo(ghi)perylene] were greater than 86%, while those of low molecular weight PAHs (i.e., from acenaphthene to pyrene) were less than 19%. Total removal efficiency for any of the nine PAHs was greater than 90% using a combination of surfactant soil washing and P. chrysosporium oxidation of soil washwater in the RBC reactor when used in batch operation, and greater than 76% when used in continuous operation. The treatment of PAH‐contaminated soil using a combination of surfactant soil washing and subsequent PAH removal from the resultant washwater in an RBC reactor, in the presence of immobilized P. chrysosporium, permits (i) a rapid abiological cleanup of soil for compliance with relevant soil quality standards and (ii) PAH biological removal in soil washwater for compliance with aqueous discharge standards.
Leaching of Nitrogen and Phosphorus during Production of Forest Seedlings in Containers
Authors: Juntunen Marja‐Liisa , Hammar Taina , Rikala Risto
Published: June 2010

Little information is available concerning the contamination risk caused by forest seedling nurseries to local surface and ground waters compared with agricultural and horticultural production. Leaching of nitrogen (N) and phosphorus (P) through peat growing medium in containers and nutrient uptake of seedlings were monitored in production of silver birch (Betula pendula Roth), Norway spruce [Picea abies (L.) Karst], and Scots pine (Pinus sylvestris L.) seedlings. About half of the applied nutrients (total amount applied = 149 to 260 kg N ha−1 and 60 to 108 kg P ha−1) was premixed into the peat medium, as is usual in Finnish nursery practice, and the other half was applied to seedlings in liquid form with mobile booms. Depending on tree species, 11 to 19% of the applied N was recovered in leachates and 15 to 63% in seedlings. The undiscovered proportion varied from 19 to 71%. The amounts of leached N were 19 to 41 kg ha−1 Only 5 to 31% of the applied P was recovered in seedlings; 16 to 64% (11 to 56 kg ha−1) was found in leachates. Total N and P load to the environment may increase substantially if nutrients applied in liquid fertilization outside container trays are included. Consequently, it is important to determine the sources of nutrient load in container seedling production to mitigate the risk of environment contamination.
Cadmium Binding by Fractions of Dissolved Organic Matter and Humic Substances from Municipal Solid Waste Compost
Authors: Kaschl Arno , Römheld Volker , Chen Yona
Published: June 2010

The agricultural practice of amending soils with composted municipal solid waste (MSW) adds significant amounts of organic matter and trace metals, including Cd. Under these conditions, soluble organic complexes of Cd formed in the compost may be more significant than previously thought, due to Cd bioavailability and mobility in the soil environment. To study the relative importance of different types of organic ligands in MSW compost for the binding of Cd, six fractions of the dissolved organic matter (DOM) in addition to humic acid (HA) and fulvic acid (FA) were extracted and their complexation of Cd quantified at pH 7 using an ion‐selective electrode (ISE). The highest complexing capacities (CC) for Cd were found for the most humified ligands: HA (2386 μmol Cd g−1 C of ligand), predialyzed FA (2468 μmol Cd g−1 C), and HoA, a fulvic‐type, easily soluble fraction (1042 μmol Cd g−1 C). The differences in CC for Cd of the various organic ligands were not directly related to total acid‐titratable or carboxylic groups, indicating the importance of sterical issues and other functional groups. The strength of association between Cd and the organic ligands was characterized by calculating stability constants for binding at the strongest sites (pKint) and modeling the distribution of binding site strengths. The pKint values of the DOM fractions ranged between 6.93 (HiN: polysaccharides) and 8.11 (HiB: proteins and aminosugars), compared with 10.05 for HA and 7.98 for FA. Hence, the highly complex and only partially soluble organic molecules from compost such as HA and FA demonstrated the highest capacity to sequester Cd. However, strong Cd binding of organic ligands containing N‐functional groups (HiB) in addition to a high CC of soluble, humified ligands like HoA indicated the relevance of these fractions for the organic complexation of Cd in solution.
Estimating Runoff Phosphorus Losses from Calcareous Soils in the Minnesota River Basin
Authors: Fang F. , Brezonik P. L. , Mulla D. J. , Hatch L. K.
Published: June 2010

Bioavailable phosphorus (BAP) in stormwater runoff is a key issue for control of eutrophication in agriculturally impacted watersheds. Laboratory experiments were conducted in soil runoff boxes to determine BAP content in simulated storm runoff in 10 (mostly) calcareous soils from the Minnesota River basin in southern Minnesota. The soluble reactive phosphorus (SRP) portion of the runoff BAP was significantly correlated with soil Mehlich‐III P, Olsen P, and water‐extractable P (all r2 > 0.90 and p < 0.001). A linear relationship (r2 = 0.88, p < 0.001) also was obtained between SRP in runoff and the phosphorus saturation index based on sorptivity (PSIs) calculated with sorptivity as a measure of the inherent soil P sorption capacity. Runoff levels of BAP estimated with iron oxide–impregnated paper were predicted well by various soil test P methods and the PSIs of the soils, but correlation coefficients between these variables and runoff BAP were generally lower than those for runoff SRP. Using these relationships and critical BAP levels for stream eutrophication, we found corresponding critical levels of soil Mehlich‐III P and Olsen P (which should not be exceeded) to be 65 to 85 and 40 to 55 mg kg−1, respectively.
Preferential Bromide and Pesticide Movement to Tile Drains under Different Cropping Practices
Authors: Fortin J. , Gagnon‐Bertrand E. , Vézina L. , Rompré M.
Published: June 2010

Subsurface drainage systems are useful tools to study chemical leaching in soils. Our objective was to compare the breakthrough behavior of bromide, atrazine (2‐chloro‐4‐ethylamino‐6‐isopropylamino‐s‐triazine) and metolachlor [2‐chloro‐N‐(2‐ethyl‐6‐methylphenyl)‐N‐(2‐methoxy‐1‐methylethyl) acetamid] to tile drains under two fall tillage practices (conventional tillage [CT] with a moldboard plow, and reduced tillage [RT] with a chisel plow) in field plots cultivated with corn (Zea maysL.). Leachate volume were greater in RT than in CT, with no statistical differences. Soil analysis showed that bromide migrated deeper in the soil profile than both herbicides, with little tillage effect. All chemicals were detected in drainage water at the same time and followed an event‐driven behavior. Tillage had no effect on atrazine and metolachlor found in drainage water, while bromide concentration peaks were higher in RT than in CT in 1999. Concentration peaks were recorded earlier for atrazine and metolachlor than for bromide. Plots of cumulative relative chemical mass (cumulative mass divided by total mass measured in drainage) as a function of cumulative drainage were mostly linear for bromide, while they were S‐shaped for both herbicides. Drainage that corresponded to 50% of relative cumulative mass ranged from 40 to 55% for bromide and from 5 to 28% for both herbicides. Rapid chemical movement to tile drains suggested that preferential flow was important in both CT and RT, and that these tillage practices had little influence on this phenomena.
Retention Equations of Nonionic Organic Chemicals in Soil Column Chromatography with Methanol–Water Eluents
Authors: Xu Feng , Liang Xinmiao , Lin Bingcheng
Published: June 2010

Research efforts dealing with chemical transportation in soils are needed to prevent damage to ground water. Methanol‐containing solvents can increase the translocation of nonionic organic chemicals (NOCs). In this study, a general log‐linear retention equation, log k′ = log k′w − Sφ (Eq. [1]), was developed to describe the mobilities of NOCs in soil column chromatography (SCC). The term φ denotes the volume fraction of methanol in eluent, k′ is the capacity factor of a solute at a certain φ value, and log k′w and −S are the intercept and slope of the log k′ vs. φ plot. Two reference soils (GSE 17204 and GSE 17205) were used as packing materials, and were eluted by isocratic methanol–water mixtures. A model of linear solvation energy relationships (LSER) was applied to analyze the k′ from molecular interactions. The most important factor determining the transportation was found to be the solute hydrophobic partition in soils, and the second‐most important factor was the solute hydrogen‐bond basicity (hydrogen‐bond accepting ability), while the less important factor was the solute dipolarity–polarizability. The solute hydrogen‐bond acidity (hydrogen‐bond donating ability) was statistically unimportant and deletable. From the LSER model, one could also obtain Eq. [1] The experimental k′ data of 121 NOCs can be accurately explained by Eq. [1] The equation is promising to estimate the solute mobility in pure water by extrapolating from lower‐capacity factors obtained in methanol–water mixed eluents.
Effect of Mineral and Manure Phosphorus Sources on Runoff Phosphorus
Authors: Kleinman Peter J. A. , Sharpley Andrew N. , Moyer Barton G. , Elwinger Gerald F.
Published: June 2010

Concern over nonpoint‐source phosphorus (P) losses from agricultural lands to surface waters has resulted in scrutiny of factors affecting P loss potential. A rainfall simulation study was conducted to quantify the effects of alternative P sources (dairy manure, poultry manure, swine slurry, and diammonium phosphate), application methods, and initial soil P concentrations on runoff P losses from three acidic soils (Buchanan–Hartleton, Hagerstown, and Lewbeach). Low P (12 to 26 mg kg−1 Mehlich‐3 P) and high P (396 to 415 mg kg−1 Mehlich‐3 P) members of each soil were amended with 100 kg total P ha−1 from each of the four P sources either by surface application or mixing, and subjected to simulated rainfall (70 mm h−1 to produce 30 min runoff). Phosphorus losses from fertilizer and manure applied to the soil surface differed significantly by source, with dissolved reactive phosphorus (DRP) accounting for 64% of total phosphorus (TP) (versus 9% for the unamended soils). For manure amended soils, these losses were linearly related to water‐soluble P concentration of manure (r2 = 0.86 for DRP, r2 = 0.78 for TP). Mixing the P sources into the soil significantly decreased P losses relative to surface P application, such that DRP losses from amended, mixed soils were not significantly different from the unamended soil. Results of this study can be applied to site assessment indices to quantify the potential for P loss from recently manured soils.
Volatilization and Degradation of Soil‐Applied Dimethylselenide
Authors: Dungan Robert S. , Yates Scott R. , Frankenberger William T.
Published: June 2010

Dimethylselenide (DMSe) is a highly volatile gas that is produced by indigenous microorganisms in seleniferous soils and sediments; however, little is known about the soil conditions that affect the persistence of DMSe and its transport to the atmosphere. In this study we investigated the effect of moisture content, temperature, and organic amendments on the degradation of soil‐applied DMSe. The degradation of DMSe was entirely a result of biological mechanisms, but changes in temperature (20–40°C) and soil moisture content (30–70% of the maximum water holding capacity) had little influence on the degradation rate. In contrast, amending soil with either 1% casein or gluten (by weight) had an inhibitory effect on the degradation of DMSe. After 18 d, 2.1 times more DMSe was present in the casein‐amended soil and 2.6 times more DMSe was present in the gluten‐amended soil. The transport of DMSe in packed soil columns was also investigated. Increasing the depth to soil surface was found to significantly decrease the amount of DMSe transported to the air. After 6 d, 57% of DMSe injected 10 cm below the soil surface was volatilized. At an injection depth of 20 cm the cumulative emissions were reduced by 38% and at 30 cm the cumulative emissions were reduced by 51%. In columns containing 1% casein or gluten in the top 5 cm of soil the cumulative loss of DMSe was about 9% higher than in unamended soil. Increasing our understanding of the soil conditions that influence the gaseous diffusion of DMSe should help in determining the feasibility of using Se volatilization as a remediation technique.
Phosphorus Characteristics of Dairy Feces Affected by Diets
Authors: Dou Zhengxia , Knowlton Katharine F. , Kohn Richard A. , Wu Zhiguo , Satter Larry D. , Zhang Gangya , Toth John D. , Ferguson James D.
Published: June 2010

Phosphorus (P) surplus on dairy farms, especially confined operations, contributes to P buildup in soils with increased potential for P loss to waters. One approach to reduce P surplus and improve water quality is to optimize P feeding and improve P balance on farms. Here we report how varying P concentrations in lactating cow diets affects the amount as well as the chemical forms and fraction distribution of P in fecal excretion, and the environmental implications of this effect. Analysis of fecal samples collected from three independent feeding trials indicates that increasing dietary P levels through the use of P minerals not only led to a higher concentration of acid digest total phosphorus (TP) in feces, but more importantly increased the amount and proportion of P that is water soluble and thus most susceptible to loss in the environment. For instance, with diets containing 3.4, 5.1, or 6.7 g P kg−1 feed dry matter (DM), the water‐soluble fraction of fecal P was 2.91, 7.13, and 10.46 g kg−1 fecal DM, respectively, accounting for 56, 77, and 83% of acid digest TP. The other fecal P fractions (those soluble in dilute alkaline and acid extractants) remained small and were unaffected by dietary P concentration. Excess P in the P supplemented diets was excreted in feces as water‐soluble forms. A simple measure of inorganic phosphorus (Pi) in a single water extract is highly responsive to changes in diet P concentrations and hence can be indicative of dietary P status. A fecal P indicator concept is proposed and discussed.
On‐Farm Evaluation of Aluminum Sulfate (Alum) as a Poultry Litter Amendment
Authors: Sims J. T. , Luka‐McCafferty N. J.
Published: June 2010

Aluminum sulfate [alum; Al2(SO4)3] amendment of poultry litters has been suggested as a best management practice to help reduce the potential environmental effects of poultry production. Past research has shown that alum treatment reduced NH3 emissions from litters, decreased the loss in runoff of P and trace metals from litter‐amended soils, improved poultry health, and reduced the costs of poultry production. We conducted a large scale, “on‐farm” evaluation of alum as a poultry (broiler) litter amendment on the Delmarva peninsula to determine the effect of alum on (i) litter properties and elemental composition and (ii) the solubility of several elements in litter that are of particular concern for water quality (Al, As, Cu, P, and Zn). Alum was applied over a 16‐mo period to 97 poultry houses on working poultry farms; 97 houses on other farms served as controls (no alum). Litter samples were analyzed initially and after approximately seven alum applications. We found that alum decreased litter pH and the water solubility of P, As, Cu, and Zn. Alum‐treated houses also had higher litter total N, NH4–N, and total S concentrations and thus a greater overall fertilizer value than litters from the control houses. Higher litter NH4–N values also suggest that alum reduced NH3 losses from litters. Thus, alum appears to have promise as a best management practice (BMP) for poultry production. Future research should focus on the long‐term transformations of P, Al, As, Cu, and Zn in soils amended with alum‐treated litters.