bluuebunny/crossref_metadata_2025 huggingface dataset:
Soil Matrix and Macropore Biodegradation of 2,4‐D
Authors: Pivetz B. E. , Steenhuis T. S.
Published: July 2010

Preferential flow of pesticides in macropores can lead to decreased travel times through the vadose zone and increased groundwater contamination. Macropores, however, may present a favorable environment for biodegradation because of greater oxygen, nutrient, and substrate supply, and higher microbial populations in earthworm burrows, compared to the soil matrix. The biodegradation of 2,4‐dichlorophenoxyacetic acid (2,4‐D) was measured in macropores and soil matrix of packed soil columns (7.0‐cm diam., 10‐cm length) and undisturbed soil cores (10‐cm diam., 7.3 or 8.0‐cm length). Each packed column contained a well‐defined artificial macropore and the undisturbed cores contained earthworm‐burrow macropores. A 50 µg/L 2,4‐D solution was continuously applied to the unsaturated soil surface and breakthrough curves (BTCs) indicating pesticide loss in the effluent were obtained from the soil matrix and macropore flow paths. Biodegradation rates were calculated separately for each flow path by comparing the BTCs to BTCs representing abiotic conditions, and dividing the 2,4‐D loss by the travel time through each flow path. The biodegradation rates increased with time in both flow paths, and the final biodegradation rate in the macropore region surpassed that of the matrix, presumably because of increased microbial populations in the macropore. Complete loss of the 2,4‐D in both flow paths was observed after continuous application of 2,4‐D for 400 h, with maximum column‐averaged 2,4‐D loss rates of 0.879 µg/(L h) in the matrix and 1.073 µg/(L h) in the macropore. Biodegradation of 2,4‐D was also observed in the macropore and matrix regions of the undisturbed soil cores.
In Situ Respirometry: Field Methods and Implications for Hydrocarbon Biodegradation in Subsurface Soils
Authors: Hickey W. J.
Published: July 2010

Using soil ventilation to promote in situ biodegradation is a promising technology for remediation of unsaturated, hydrocarbon‐contaminated, subsurface soils. Evaluating in situ hydrocarbon biodegradation rates and levels is a critical part of this approach and determining changes in subsurface O2 and/or CO2 levels is a convenient method for monitoring this process because repetitive, noninvasive measurements can be made. In this study, two rapid field procedures for gas analysis, using either liquid‐ or solid‐phase absorption of O2 and CO2, were compared and the implications of these gas measurements for evaluating in situ hydrocarbon biodegradation considered. Air samples were taken from 5 vadose zone piezometers in a gasoline‐contaminated soil under treatment by a soil vapor extraction system and one piezometer in a noncontaminated background area. Similar rates and levels of O2 consumption and CO2 production were obtained by both techniques during the 20‐d study; thus, the method of choice will depend on factors such as cost, air sample volume limitations, or the need for contaminant vapor analyses in the field. While these techniques were good assays for relative microbial activity levels, significant discrepancies between predicted and measured CO2 levels raised questions concerning the validity of basing hydrocarbon biodegradation estimates solely on O2 consumption data. To improve the reliability of in situ fuel biodegradation estimates based on O2 measurements, the relationship(s) between metabolic activities of microbial populations in hydrocarbon‐contaminated soils, and changes in subsurface O2 and CO2 levels should be clarified.
Distribution and Persistence of Azinphos‐Methyl and Parathion in Chemigated Cranberry Bogs
Authors: Wan Michael T. , Szeto Sunny Y. , Price Patricia
Published: July 2010

Ditches draining two cranberry (Vaccinium spp.) bogs flowing into salmon (Oncorhynchus spp.) bearing waterbodies in the Lower Fraser Valley of British Columbia, Canada, were sampled in 1992 to determine the distribution and persistence of azinphos‐methyl (AZI) and parathion (PAR) following three treatments through an irrigation system (chemigation), to control the black‐headed fireworm (Rhopobota naevana Hbn). One bog was surrounded by a secured dike system for water retention and the other by a leaking dike system, representing a worst‐case scenario. After each treatment, AZI and PAR residues were detected in ditch water (detection limit = 0.05 µg/L) and sediments (detection limit = 5 µg/kg) inside and outside the bogs and they persisted for 72 and 32 d, respectively. The highest concentrations in water were 175 µg/L for AZI and 21 µg/L for PAR. Concentrations of AZI and PAR in sediments ranged from not detected to 1582 µg/kg and persisted for 210 and 13 d, respectively. Low levels of aerial drift resulting from the treatment were detected beyond the outer perimeter of the sprinkler irrigation system in the cranberry bogs. Off‐site release of insecticide residues occurred in the leaking dike system but not in the secured dike system. The released insecticide residues adversely affected nontarget aquatic organisms. Harvested cranberries contained no detectable (detection limit = 5 µg/kg) residues of AZI and PAR.
Biosolids Effect on Phosphorus, Copper, Zinc, Nickel, and Molybdenum Concentrations in Dryland Wheat
Authors: Barbarick K. A. , Ippolito J. A. , Westfall D. G.
Published: July 2010

When biosolids that are low in trace elements are applied on cropland, the tissue concentrations of trace elements may approach a concentration plateau as cumulative quantity of the element added increases. If the plateau concentration is less than that of safe threshold, the application may continue indefinitely. We found that wheat (Triticum aestivum L. ‘Vona’ or ‘TAM107’) grain concentrations of P, Cu, Zn, and Ni from an 11‐yr field study of biosolids land application follow a plateau model. The grain concentrations of P, Cu, and Zn approach the calculated plateau maximum after 11 applications (in fallow rotation, we completed six applications to one set of plots plus five applications to a second set). Grain Ni levels show a linear response to cumulative inputs of biosolids Ni. Possibly, the biosolids are providing a labile source of Ni. The Mo concentrations did not change significantly as cumulative inputs of biosolids Mo increased. Our results indicate that plateau modeling can describe the changes in wheat grain concentrations associated with biosolids application.
Tree Survival and Growth on Land Reclaimed in Accord with Public Law 95‐87
Authors: Chaney William R. , Pope Phillip E. , Byrnes William R.
Published: July 2010

The objective of this study was to determine survival and growth of black walnut (Juglans nigra L.) and northern red oak (Quercus alba L.) 12 yr after planting on a surface‐mined site in southern Indiana reclaimed according to specifications of Public Law 95‐87, the Surface Mining Control and Reclamation Act of 1977. A stocking level adequate to meet the requirements for forest land use (1112 trees/ha, or 450 trees/acre) was attained only for black walnut and only if competing ground cover vegetation was controlled in the tree rows. Height of both tree species was significantly greater when ground cover vegetation was controlled during the first 2 yr, but the growth rate, approximately 10 cm/yr, was very slow.
Spatial and Temporal Variation in Groundwater Nitrate Removal in a Riparian Forest
Authors: Nelson William M. , Gold Arthur J. , Groffman Peter M.
Published: July 2010

We quantified nitrate (NO−3) removal rates from groundwater in a red maple (Acer rubrum L.) riparian forest subjected to NO−3 dosing. The site was in Southern New England on soils classified as sandy mixed mesic Haplaquept soils and contained somewhat poorly (SPD) and poorly drained (PD) soils. The specific objectives were to examine groundwater NO−3 removal rates within a riparian forest with respect to: (i) soil drainage class; (ii) depth below water table; and (iii) time of year. We created 16 experimental dosing/monitoring stations at two depths along three soil drainage class transects (SPD, SPD/PD, PD). We added solution containing NO−3 and Br− continuously for 11 mo to a dosing well at each station. Groundwater was monitored at sampling wells 0.6 m downgradient of the dosing well. Nitrate removal rates were determined by coupling changes in the NO−3/Br− ratio with groundwater flux estimates from each experimental station. Although located just 20 m downgradient, the PD transects had substantially higher NO−3 removal rates and lower dissolved oxygen than the SPD transects. Both the SPD/PD and PD transects had considerable NO−3‐N removal capacity throughout the upper 1.5 m of the groundwater (16–46 µg kg−1 d−1). Rates were not significantly influenced by temperature. The scale of variation in removal rates suggests that high resolution soil and groundwater maps may be needed when riparian forests are to be used for water quality management.
The Effect of Moisture and Soil Texture on the Adsorption of Organic Vapors
Authors: Petersen L. W. , Moldrup P. , El‐Farhan Y. H. , Jacobsen O. H. , Yamaguchi T. , Rolston D. E.
Published: July 2010

The fate of volatile organic compounds (VOCs) moving as vapors in the subsurface is dependent on their interaction with the soil. Adsorption of VOC vapors is greatly influenced by soil texture and soil‐water content. The effects of differences in texture and soil‐water content on vapor partition coefficients for trichloroethylene (TCE) were examined. Batch experiments were conducted for a variety of soils and at different soil‐water contents, w, to determine the relationship between the vapor/solid partition coefficient, KD′, and w. In dry soils, KD′ was nonlinearly related to soil‐water content because, in that range, water molecules compete with VOC molecules for adsorption sites on the soil surface. Under wet conditions, KD′ became linearly related to water content according to Henry's law, indicating that adsorbed water molecules were acting as a solvent for VOC molecules. In general, KD′ under oven‐dry conditions did not relate well to total specific surface area of soils, most likely because VOC molecules adsorb only on the outside surfaces of soil particles (due to their nonpolarity), rather than the total surface area present. In the dry range, adsorption was dominated by soils with high specific areas (i.e., high clay content), while soils with higher organic carbon content manifested higher adsorption amounts in the wet moisture range. A one‐parameter, exponential model well described the log KD′‐w curve in the nonlinear region. The model parameter, a, was found to be highly dependent on the specific surface area of the soil. The proposed KD′‐(w) model incorporated in conventional VOC transport models seems promising for analyzing the effects of VOC vapor adsorption on VOC subsurface transport.
Plant Selenium from Soil and the Atmosphere
Authors: Haygarth Philip M. , Harrison Anthony F. , Jones Kevin C.
Published: July 2010

Transfer of selenium (Se) to pasture is important for prevention of Se deficiency in livestock, yet little is known about the relative importance of inputs to pasture from soil and the atmosphere. An isotope dilution method was used to assess quantitatively the importance of these inputs to ryegrass. Soil was labelled with 75Se and subjected to two field treatments that were untreated (pH 6.0) and limed (pH 7.0). After an initial period of equilibration, the specific activity of Se associated with unwashed leaves became lower than that of soil. This indicated that atmospheric Se had been deposited onto and possibly incorporated into the ryegrass. The percent contribution of 75Se in pasture leaves derived from the soil was 47% (pH 6.0) and 70% (pH 7.0), with, by inference, the remainder coming from the atmosphere.
Linking a Geographic Information System with a Potato Simulation Model for Site‐Specific Crop Management
Authors: Han S. , Evans R. G. , Hodges T. , Rawlins S. L.
Published: July 2010

Site‐specific crop management (SSCM) requires that crop simulation models be applied to subareas of a field to test or develop management practices. When the number of subareas is sufficiently large, crop simulation models should be linked with a geographic information system (GIS) for ease of input data preparation and for output data analysis. An interface between PC ARC/INFO (a GIS) and SIMPO‐TATO (a potato growth simulator) was developed to study potato (Solanum tuberosum L.) yield and N leaching distributions. The most important distributed input parameters were identified as the irrigated water/N, soil texture, and initial soil N. An example usage of the interface program is given to study the N leaching under different management scenarios.
Denitrification in a Restored Riparian Forest Wetland
Authors: Lowrance Richard , Vellidis George , Hubbard Robert K.
Published: July 2010

Groundwater nitrate moving from upland areas toward streams can be removed by denitrification in mature riparian forests, but denitrification in restored riparian forests has not been quantified. We determined denitrification rates in a restored riparian wetland below a liquid manure application site. A riparian forest buffer consisting of hardwoods along the stream and pines above the hardwoods was established according to USDA specifications. Denitrification was measured monthly using the acetylene inhibition technique on intact soil cores for 2 mo before manure application began and for 24 mo after manure application. Groundwater movement of NO3−‐N and total Kjeldahl N were estimated biweekly. Average annual denitrification rate was 68 kg N2O‐N ha−1 yr−1. Denitrification was significantly higher in a grassed area than in either of the forested areas. Denitrification did not differ significantly between the hardwood and pine areas. Denitrification was greater than a conservative estimate of groundwater input of total N. Denitrification rates were higher in April and May 1992 and 1993, after manure application to the upland began, compared with April and May 1991, before manure application began. These results indicate that a riparian wetland, which has not undergone hydrologic modifications, can have denitrification rates comparable to mature riparian forests. Higher denitrification rates in an adjacent grassed wetland and lack of differences in denitrification in hardwood and pine zones indicates that the high denitrification rates were due to factors other than the reforestation itself. Compared with groundwater inputs of N, denitrification was an important sink for N moving from the upland management system.
The Effects of pH, Flow Rate, and Carbon Supplementation on Manganese Retention in Mesocosm Wetlands
Authors: Stark Lloyd R. , Wenerick William R. , Williams Frederick M. , Wuest Paul J.
Published: July 2010

In an effort to obtain design parameters, a wetland mesocosm experiment was conducted to determine the effects on Mn retention of flow rate, inlet pH, and C supplementation. Sustained Mn retention was not achieved under reducing conditions when spent mushroom substrate was used as a substrate irrespective of flow rate, inlet pH, and C supplementation regimes. However, a lowered flow rate resulted in many significant effects on outlet water chemistry, including lower outlet Mn concentrations, higher outlet pH, lower outlet acidity, higher outlet alkalinity, higher outlet sulfide, lower outlet sulfate, and lower outlet redox potential. Supplementation of the wetlands with dairy whey resulted in marginally lower outlet Mn concentrations and marginally higher outlet sulfide levels. Wetlands receiving a neutral pH had lower outlet acidity, higher outlet alkalinity, lower outlet sulfate, but equivalent outlet Mn concentrations to wetlands receiving an acidic pH. Sulfate reduction was stimulated by reducing flow rates and metal loads. Metal extractions indicated that most of the Mn was retained as exchangeable Mn (37%), carbonate‐bound Mn (30%), and oxide‐bound Mn (21%), with most (64%) of the Mn retained at the surface of the wetland. The dominant form of Mn found in the subsurface substrate samples was exchangeable Mn (44%), indicating that stable forms of Mn did not form under reducing conditions.
Characterization and Leaching of Elements from Municipal Solid Waste Compost
Authors: Tisdell Shawn E. , Breslin Vincent T.
Published: July 2010

Municipal solid waste (MSW) compost was collected from the St. Cloud, MN and Pembroke Pines, FL composting facilities on several occasions during 1990 to 1993. The total content, phase association, and water solubility of cadmium (Cd), lead (Pb), iron (Fe), copper (Cu), chromium (Cr), nickel (Ni), and zinc (Zn) were determined using sequential chemical extraction (SCE) and synthetic acid rainwater cascade (SRC) extraction protocols to assess the environmental acceptability of MSW composts. The MSW composts are enriched with Pb (314–671 mg/kg), Cd (2.6–10.8 mg/kg), Cu (121–762 mg/kg), and Zn (540–2790 mg/kg). The SRC leachable fraction of Cu, Zn, Cd, Cr, Pb, and Fe was <6% in the Pembroke Pines compost and <10% in the St. Cloud compost. Nickel solubility, however, was high and variable in the composts studied. The SRC‐extractable Ni ranged from 11.3% for Pembroke Pines compost to 56.2% for St. Cloud compost. The SCE‐exchangeable fraction of Cu, Cr, Ni, Zn, and Fe in these composts was <4%. Cadmium was an exception, where 12.8 and 10.3% of the Cd was extracted from the SCE‐exchangeable phase of the St. Cloud and Pembroke Pines composts, respectively. Higher Cd contents of the SCE‐exchangeable phase extractions in comparison to the SAR leachates for these composts is attributed to the formation of soluble Cd complexes because of the use of MgCl2 as the SCE exchangable phase extraction fluid.
Modeling Adsorption‐Desorption Kinetics of Alachlor in a Typic Fragiudalf
Authors: Xue S. K. , Selim H. M.
Published: July 2010

Adsorption and desorption kinetics are essential components for modeling the fate of pesticides in soils. This study was conducted to characterize the kinetics of alachlor [2‐chloro‐N‐(2,6‐diethylphenyl)‐N‐(methoxymethyl) acetamide] adsorption and desorption in Gigger (fine‐silty, mixed, thermic Typic Fragiudalf) surface soil samples collected from long term no‐till and conventional tillage plots. A batch method was used to determine alachlor adsorption with time up to 528 h for a range of input concentrations from 0.5 to 50 mg/L. Successive dilution was used to quantify desorption kinetics following 16, 32, 64, 128, 256, and 512 h of adsorption. For both samples, alachlor time‐dependent results indicated initially fast adsorption followed by slow adsorption where kinetic reactions appeared dominant. Adsorption‐desorption showed extensive hysteretic behavior resulting from discrepancies between adsorption and desorption isotherms. Hysteresis was more pronounced with increased reaction time of adsorption. Four variations of a nonlinear multireaction kinetic model successfully described retention results. Adsorption and desorption, however, were best described by a model version incorporating nonlinear equilibrium, a kinetic reversible mechanism, and a consecutive irreversible mechanism. The model was successfully used in describing alachlor adsorption and desorption results. The model predicted the overall alachlor hysteresis satisfactorily except that, at large times, desorption isotherms were not considered adequate. The model also was capable of predicting alachlor desorption kinetics based solely on parameters obtained from adsorption experiments.
Mineralization and Leaching of Nitrogen in an Effluent‐Irrigated Pine Plantation
Authors: Polglase P. J. , Tompkins D. , Stewart L. G. , Falkiner R. A.
Published: July 2010

In Australia, irrigating tree plantations with domestic sewerage effluent is becoming an increasingly common and necessary alternative to disposal of effluent in rivers. This study estimated field rates of soil N mineralization and concentrations of N in soil solution under a newly established stand of radiata pine (Pinus radiata D. Don) to which secondary‐treated sewerage effluent was applied by spray‐irrigation at various rates. These rates nominally were: medium treatment (M) irrigated at the rate at which water was used by the plantation (allowing for inputs in rain); high treatment (H) irrigated at twice the rate M; low treatment (L) irrigated at half the rate M; and a bore‐water control (W, groundwater containing no N or P) irrigated at the rate of water use (less rainfall). Annual rates of in situ N mineralization were large in all treatments, ranging from 290 kg ha−1 in the L treatment to 410 kg ha−1 in the H treatment. The amount of soil N decreased, on average, by about 190 kg ha−1 during the first two irrigation seasons in the H, M, and W treatments. A total of 374 kg of N was added in effluent during the first three irrigation seasons in the H treatment. Despite this addition and the large amount of N mineralized, most of which was nitrified, leaching of NO3‐N (and of total N) was limited. During a 2‐yr sampling period, for example, the concentrations of NO3‐N leaching at 100 cm averaged only 1.1 mg L−1 across all treatments. Weed growth and weed management, in combination with irrigation and its effect on soil moisture availability can greatly influence soil N turnover and leaching in young tree plantations.
Dependence of Runoff Phosphorus on Extractable Soil Phosphorus
Authors: Sharpley Andrew N.
Published: July 2010

The sustainable management of fertilizer and manure P to minimize freshwater eutrophication requires identification of soil P levels that exceed crop P requirements and have the potential for P enrichment of runoff. Although several states have established such P levels, insufficient data are available to theoretically justify them. Thus, this study investigates the relationship between the concentrations of P in runoff and in soil. Surface samples (0–10 cm) of 10 Oklahoma soils were packed in 0.15 m2 boxes, incubated for 7 d with poultry litter (0–20 Mg ha−1) to obtain a range in Mehlich‐3 P contents (7–360 mg kg−1), and received five 30‐min rainfalls applied at 1‐d intervals. The concentration of dissolved, bioavailable, and particulate P in runoff was related (r2 > 0.90; P < 0.1) to the Mehlich‐3 P content of surface soil (0–1 cm), with regression slopes ranging from 2.0 to 7.2, increasing as soil P sorption maxima increased (r2 = 0.93). Two soils of 200 mg kg−1 Mehlich‐3 P supported a dissolved P concentration in runoff of 280 μg L−1 (San Saba clay; fine, montmorillonitic, thermic Udic Pellustert) and 1360 μg L−1 (Stigler silt loam; fine, mixed, thermic Aquic Paleudalf). Thus, relationships between runoff and soil P will have to be soil specific for use in management recommendations. A single linear relationship described the dependence of dissolved (r2 = 0.86) and bioavailable P (r2 = 0.85) on soil P sorption saturation. The added complexity of the P saturation approach may limit its application; however, the approach integrates the effect of soil type with soil P content to better estimate the potential for P loss in runoff than soil P alone.
Agricultural Impacts on Bacterial Water Quality in Karst Groundwater
Authors: Pasquarell G. C. , Boyer D. G.
Published: July 2010

A 2‐yr study (1991–1992) was conducted in a karst region in southeast West Virginia to determine the impact of agriculture on groundwater quality. The primary agriculture is characterized by seasonal cattle grazing. Fecal coliform densities were measured weekly in the resurgences of three karst basins possessing different degrees of agricultural intensity (79, 51, and 16% land use in agriculture). Fecal coliforms were also measured in a creek at sites upstream and downstream of the known resurgences from the most agriculturally intensive (79%) basin. The fecal coliform densities in the resurgences peaked in the summer and declined in the fall, with a recovery in late winter before the introduction of new cattle. The timing of the recovery indicated that significant storage of fecal material had taken place, which was transported to the groundwater when soil water conditions permitted. For most of each year, soil water effects appeared to have a greater bearing on the fecal coliform densities than did the presence or absence of cattle. The data did not generally support a strong relationship with percent land use in agriculture. This was attributed to the high variability in the data and to low soil moisture during periods of recession that inhibited the transport of fecal material to the groundwater. The karst resurgence springs of the most intensively agricultural basin were contaminated with fecal bacteria. Fecal bacteria concentrations were observed to significantly increase, in the receiving surface stream, from a point upstream of the resurgence springs to a point downstream of the resurgence springs.
Prediction of Areas Where Irrigation Drainage May Induce Selenium Contamination of Water
Authors: Seiler Ralph L.
Published: July 2010

The U.S. Department of the Interior has investigated 25 areas in the western USA to determine whether irrigation drainage has caused harmful effects on wildlife or has reduced subsequent beneficial uses of the water. A database of chemical analyses of water, sediment, and biota from the 25 areas was created and supplemented with geologic, climatologic, and hydrologic data. The data were evaluated to identify common features among study areas and principal factors that result in Se contamination of water in lakes, ponds, and streams downgradient of irrigated areas. From the analysis of data, a decision tree that uses readily available geologic, climatologic, and hydrologic data was derived for use by resource managers as a screening tool to predict the likelihood that irrigation drainage will result in Se contamination in areas of the western USA. Irrigation in areas that are not associated with marine sedimentary rocks of late Cretaceous age is unlikely to cause Se contamination. Irrigation in very arid areas that are associated with these Cretaceous sediments is almost certain to cause Se contamination if the irrigation water drains to terminal lakes and ponds. The likelihood that an area will be contaminated with Se because of irrigation drainage can change, particularly with changes in precipitation. During normal or wet periods, Se contamination may not occur in an area, even though it has seleniferous soils, but reduced water deliveries during a drought in such an area may result in Se contamination.
Heavy Metal Concentrations in Plants in Relation to Atmospheric Heavy Metal Deposition
Authors: Berthelsen B. O. , Steinnes E. , Solberg W. , Jingsen L.
Published: July 2010

Zinc, Cu, Pb, and Cd concentrations were examined in several plant species and corresponding organic topsoil collected in forest and on ombrotrophic bogs along a temporal (1982–1992) and a spatial (Southern Norway‐Central Norway) heavy metal deposition gradient. This allowed relations between metal concentrations in plants, soil/peat, and spatial and temporal changes in atmospheric deposition of heavy metals to be studied. Lead concentrations in plants decreased significantly from 1982 to 1992 both in Southern and Central Norway, while stable levels were observed in surface soil. These observations together with a decrease in atmospheric Pb deposition rates of about 70% both in Southern and Central Norway, suggests that direct atmospheric deposition strongly influenced Pb levels in vegetation. Lead concentrations in vegetation were significantly higher in Southern Norway than in Central Norway both in 1982 and 1992, evidently due to a more than 15 times higher Pb deposition in Southern Norway. Plant concentrations of Zn, Cu, and Cd were significantly higher in Southern Norway than in Central Norway, both in 1982 and 1992, most likely because of higher root uptake in Southern Norway due to distinctly higher surface soil levels of Zn, Cu, and Cd from air pollution in this region. No distinct changes in Zn, Cu, or Cd concentrations in plants, however, where observed from 1982 to 1992, even in Southern Norway where wet deposition of these elements decreased by about 26% (Zn), 40% (Cu), and 51% (Cd) during this period.
Minespoil Amendment with Dry Flue Gas Desulfurization By‐Products: Plant Growth
Authors: Stehouwer R. C. , Sutton P. , Dick W. A.
Published: July 2010

One potential use for alkaline, dry flue gas desulfurization (FGD) by‐products is in reclamation of acidic minespoils. Greenhouse column studies of 8‐mo duration investigated growth and tissue composition of plants grown on three acidic minespoils amended with two dry FGD by‐products (lime injection multistage burners, LIMB; and, pressurized fluidized bed combustion, PFBC). Amendment amounts ranged from 0 to 320 g kg−1 by dry weight. Two minespoils also were amended with sewage sludge at 60 g kg−1 by dry weight. Column mixes were planted with Kentucky 31 tall fescue (Festuca arundinacea Schreb.). After 92 d of growth, fescue was harvested every 30 d for a total of six harvests. Tissue composition was determined on material from the sixth harvest. Root growth was measured at the end of the experiment. Fescue growth was improved by FGD amendments of 30 to 120 g kg−1, but larger amendments caused high pH and cementation, which decreased fescue growth and limited rooting volume. Plant tissue composition was generally within sufficiency ranges for the elements analyzed. Tissue Ca, Mg, and S were increased by FGD amendment, while tissue concentrations of most trace elements were decreased. There was no increase in tissue B from PFBC, however, LIMB application caused B concentrations >100 mg kg−1, which could be toxic to less tolerant species. These results indicate that when applied in amounts equivalent to spoil neutralization needs, dry FGD by‐products can benefit acidic spoil revegetation with little potential for introduction of toxic elements into the food chain.
Paper Sludge Utilization in Agriculture and Container Nursery Culture
Authors: Bellamy K. L. , Chong C. , Cline R. A.
Published: July 2010

During the last 10 yr, research was established in the Niagara region of Ontario to assess the use of paper sludge on agricultural land. Compositionally, the sludges are relatively free of chemical contaminants. These sludges are used primarily as an organic amendment rather than as fertilizers, because of low mineral nutrient contents. Greenhouse, nursery container media, and field experiments showed increased growth and yield of various horticultural and agricultural crops, thus demonstrating the beneficial effects of paper sludges as organic amendments to potting media and field soils. Small to moderate deficiencies in N in certain sludges are readily compensated by adding fertilizer to soil or sludge. From field plot studies, increases in growth and yield for selected crops have been realized with a recommended sludge application rate of 12 dry Mg ha−1 provided sufficient N fertilizer is applied.
Pesticides in Near‐Surface Aquifers: An Assessment Using Highly Sensitive Analytical Methods and Tritium
Authors: Kolpin Dana W. , Goolsby Donald A. , Thurman E. Michael
Published: July 2010

In 1992, the U.S. Geological Survey (USGS) determined the distribution of pesticides in near‐surface aquifers of the midwestern USA to be much more widespread than originally determined during a 1991 USGS study. The frequency of pesticide detection increased from 28.4% during the 1991 study to 59.0% during the 1992 study. This increase in pesticide detection was primarily the result of a more sensitive analytical method that used reporting limits as much as 20 times lower than previously available and a threefold increase in the number of pesticide metabolites analyzed. No pesticide concentrations exceeded the U.S. Environmental Protection Agency's (USEPAs) maximum contaminant levels or health advisory levels for drinking water. However, five of the six most frequently detected compounds during 1992 were pesticide metabolites that currently do not have drinking water standards determined. The frequent presence of pesticide metabolites for this study documents the importance of obtaining information on these compounds to understand the fate and transport of pesticides in the hydrologic system. It appears that the 56 parent compounds analyzed follow similar pathways through the hydrologic system as atrazine. When atrazine was detected by routine or sensitive analytical methods, there was an increased likelihood of detecting additional parent compounds. As expected, the frequency of pesticide detection was highly dependent on the analytical reporting limit. The number of atrazine detections more than doubled as the reporting limit decreased from 0.10 to 0.01 µg/L. The 1992 data provided no indication that the frequency of pesticide detection would level off as improved analytical methods provide concentrations below 0.003 µg/L. A relation was determined between groundwater age and the frequency of pesticide detection, with 15.8% of the samples composed of pre‐1953 water and 70.3% of the samples of post‐1953 water having a detection of at least one pesticide or metabolite. Pre‐1953 water is less likely to contain pesticides because it tends to predate the use of pesticides to increase crop production in the Midwest. Pre‐1953 water was more likely to occur in the near‐surface bedrock aquifers (50.0%) than in the near‐surface unconsolidated aquifers (9.1%) sampled.
Short‐Term Changes in the Molybdate Reactive Phosphorus of Stored Soil Waters
Authors: Haygarth P. M. , Ashby C. D. , Jarvis S. C.
Published: July 2010

Precise determination of molybdate reactive phosphorus (MRP) in waters is needed to accurately quantify sources of bioavailable phosphorus (P) entering into fresh water systems. Leachate waters from soils were collected from lysimeters to study the short‐term stability of MRP during sample storage from 2 h up to 32 d. The effects of different chemical preservatives (iodine, sulfuric acid, and mercury) were different in different soil water types, sometimes causing an increase in MRP a few days after storage. The effects of storage environment (refrigeration, freezing, outside, darkness, and in ambient laboratory conditions) also varied between soil types, with the least changes noted in samples stored in the ambient laboratory conditions and under refrigeration. Larger vessels (25 L) retained MRP more effectively than smaller vessels (30 mL) and teflon‐polytetrafluoroethylene (PTFE) was the vessel material preferred to polyethylene and polythene. The mechanisms responsible for the changes are thought to be a complex interaction between biological (microbial incorporation/release), chemical (adsorption/desorption and hydrolysis), and physical (presence/absence of particle material) factors. The conclusions were that different waters behave differently, that losses are rapid (hours and days) and that rapid analysis is essential to provide a correct assessment of water quality.
Subsurface Mobility of Metribuzin as Affected by Crop Residue Placement and Tillage Method
Authors: Dao Thanh H.
Published: July 2010

The role of crop residues as a sorptive layer for herbicides applied in conservation tillage systems is not well understood. The organic mulch may retain herbicides and decrease chemical mobility and off‐site transport. Field and laboratory experiments were conducted to determine the effects of surface placement of crop residues on herbicide mobility in Norge silt loam (fine‐silty, mixed, mesic Udic Paleustoll). In the field, four treatments were established that included no‐till plots with all crop residues removed (NTRR), residues left standing (NTRS), residues cut and laid flat on ground (NTRF), and plots that were moldboard plowed to incorporate residues (MT). An application of 1.15 kg ha−1 of metribuzin [4‐amino‐6‐(1,1‐dimethyl‐ethyl)‐3‐(methylthio)‐1,2,4‐triazine‐5(4H)‐one] and 50 kg ha−1 of potassium bromide was made. Soil cores were taken to 1‐m depth following an initial sprinkler irrigation and natural rainfalls. Wheat residues intercepted metribuzin and attenuated subsurface movement in NT soils. Standing crop residues or residues placed flat on the soil surface resulted in more metribuzin in the near‐surface zone; centers of mass of concentration distributions in NTRS and NTRF soils showed that metribuzin moved only 47 to 62% of the distance observed in MT soil after 45 and 175 mm of precipitation, respectively. Addition of straw matter to soil and elevated organic C concentrations in the near‐surface zone of no‐till soils resulted in two‐ to fivefold increase in metribuzin retention. Therefore, placement geometry of crop residues and the retention capacity of the near‐surface zone could be managed to attenuate metribuzin mobility in the field to achieve optimal herbicidal functions and dissipation.
Sewage Sludge and Heavy Metal Effects on Nodulation and Nitrogen Fixation of Legumes
Authors: Ibekwe A. M. , Angle J. S. , Chaney R. L. , van Berkum P.
Published: July 2010

Effects of sludge‐borne heavy metals on plant growth, nodulation, and nitrogen (N2) fixation of alfalfa (Medicago sativa L.), white clover (Trifolium repens L.), and red clover (Trifolium pratense L.) were examined. Plants were grown in the greenhouse in pots containing soil (Typic Paleudults) obtained from plots where heat‐treated and Nu‐Earth sludges were applied in 1976 and 1978, respectively. Two soil pH regimes (low and high) were examined for each of the treatments. Nitrogen fertilizer (NH4NO3) was applied to one‐half the pots and each legume was inoculated with the appropriate Rhizobium culture. Soil pH and sludge type significantly affected uptake of metals with phytotoxicity observed in the Nu‐Earth, low pH soil. Nodulation was reduced, but not always completely eliminated in all low pH treatments, including the controls. Symbioses were generally ineffective in low pH treatments. In soils where pH was above 6.0, there was a significant increase in shoot weight and total shoot N with sludge addition. Plants derived significant quantities of N from soil, where sludge was applied many years ago. When pH was maintained at 6.0 or higher the results show that heavy metals in soil, and the resulting concentration in plants, had no effect on any of the parameters examined.
Synthetic Ion‐Exchange Resins: Soil and Environmental Studies
Authors: Skogley Earl O. , Dobermann Achim
Published: July 2010

The use of synthetic ion‐exchangers (commonly referred to as resins) to study natural media has steadily increased. These materials allow new and different ways to solve problems that cannot be resolved through usual approaches. A lack of knowledge or limited experience, however, has led to apparent confusion concerning appropriate use of resins for soil and environmental studies. The objective of this paper was to provide basic information on ion‐exchange resins, their physical and chemical properties, and to review how resins have been used to expand our understanding of soils and other environmental media. A review of the literature is presented as an aid to better understanding, and to provide additional sources for details concerning resin applications. A classification scheme for resin systems is presented, with the intent that it will assist in the development of more uniformity and comparability in the use of resins for soil and environmental studies. Applications of various systems and their limitations are discussed, including a system developed to provide universal adsorption of ions and bioavailability indexes from tests run either in the laboratory or in situ.
Pollutant Sources, Depositional Environment, and the Surficial Sediments of Onondaga Lake, New York
Authors: Auer Martin T. , Johnson Ned A. , Penn Michael R. , Effler Steven W.
Published: July 2010

A physical and chemical characterization of the surficial sediments of polluted, hypereutrophic Onondaga Lake, New York is presented. Seventy samples were analyzed for a suite of parameters: particle size, moisture content, volatile solids, calcium carbonate, clastics, N, P, chemical oxygen demand, and inorganic and organic C. The lake's sediments are enriched in calcium carbonate (averaging 66% dry weight, DW), at least in part due to an industrial discharge of Ca2+. Enrichment with calcium carbonate serves to dilute other sediment constituents, yielding concentrations of N, P, and organic matter (volatile solids) unusually low for a hypereutrophic system. The distribution of sediment constituents is strongly influenced by lake morphometry: fine sediments (Φ = 4.6) relatively high in N (0.45% DW), P (0.12% DW), and volatile solids (10.7% DW) are characteristic of low energy, deep‐water depositional environments and coarse (Φ = 1.7), calcium carbonate‐rich (83% DW) sediments are typical of shallow, high energy nearshore sites. The location of tributary and point source inputs and the lake's predominant circulation pattern also influence the distribution of clastics, organic matter, and P. Cluster analysis was used to identify regions of common sediment character: (1) nearshore sediments rich in calcium carbonate, (2) shallow water sediments directly influenced by tributary and point source discharges, and (3) deep‐water sediments rich in N, P, and organic matter. The deep‐water sediment type was further subdivided in recognition of the high chemical oxygen demand characteristic of the deepest portions of the depositional basin.
Reversing Acidification in a Forested Catchment in Southwestern Sweden: Effects on Soil Solution Chemistry
Authors: Giesler Reiner , Moldan Filip , Lundström Ulla , Hultberg Hans
Published: July 2010

The exclusion of acid precipitation in whole‐catchment experiments can provide valuable information to further our understanding of recovery processes of acidified soils. In this study, we focused on the reversibility of acidification‐induced changes in different soil horizons when anthropogenic deposition was excluded. A small forested catchment in the Gårdsjön area in southwest Sweden was covered with a transparent roof in April 1991 and sprinkled with water that simulated preindustrial deposition levels. Within the roofed catchment and a reference catchment the soil solution was studied using a centrifugation drainage technique. Sulfate concentrations in the O and E horizons decreased by 75 and 65%, respectively, within 3 mo after treatment. In the Bs horizon, the sulfate concentration decreased more gradually, reaching about 52% of the pretreatment level in 1993 after 2.5 yr of treatment. The decline in sulfate concentrations in the runoff followed the pattern observed in the Bs horizon. The net loss from the catchment during the first 2.5 yr of the treatment period represents approximately 9% of the phosphate‐extractable sulfate pool. No increase in soil solution pH occurred until 1994. In 1993, Al concentrations were lower compared with those found in earlier samplings of the soil solution and runoff. Fluctuations in Al concentrations were correlated most strongly with changes in ionic strength in the soil solution and runoff. Nitrate concentrations remained unchanged in the soil solution and runoff. Concentrations of NO−3 were, however, already low (<30 µmol L−1) before the exclusion.
Calibration and Testing of Simulation Models for Evaluation of Trench Cap Designs
Authors: Paige G. B. , Stone J. J. , Lane L. J. , Hakonson T. E.
Published: July 2010

A prototype decision support system (PDSS) using multi‐objective decision theory and embedded simulation models is being developed to evaluate landfill cover designs for low‐level radioactive waste disposal sites. To evaluate the performance of the PDSS, the simulation models, which are used to parameterize the decision model when data are not available, must be calibrated and tested. The two linked simulation models embedded in the PDSS are the HELP (hydrologic evaluation of landfill performance) and CREAMS (chemicals, runoff, and erosion from agricultural management systems) models. Data from a field demonstration study at Hill Air Force Base were used to calibrate the simulation models. The models were calibrated using water balance and erosion parameters for two alternative designs, a control soil cover and a modified USEPA Resource Conservation and Recovery Act design. Simulations were run using the calibrated model parameters for a 200‐yr period to evaluate the long‐term performance of the models. The progressive annual average for all of the output parameters was within the 95% confidence limits of the long‐term mean by Year 60 for both of the cover designs evaluated. The results of the calibration and long‐term evaluation of the simulation models were reasonable for the length of the data set. To fully validate and test the simulation models, other data sets of landfill covers in a variety of climates are needed.
Effects of Olestra in Sewage Sludge on Soil Physical Properties
Authors: Logan T. J. , Harrison B. J. , McAvoy D. C. , Greff J. A.
Published: July 2010

This study investigated the potential effects of olestra, a fat replacer, on soil physical properties following amendment in sewage sludge. Liquid and solid forms of olestra, ranging the product formulation properties, were added to anaerobically digested sludge at concentrations of 5.7 and 4.4% by weight, respectively. Sludges, with and without the two olestra formulations, were dewatered to 45% solids by weight and uniformly mixed with four distinctly different soils: Miamian silt loam (fine, mixed, mesic, Typic Hapludalf), Kokomo silt loam (fine, mixed, mesic, Typic Argiaquoll), Hazleton sand (loamy‐skeletal, mixed, mesic, Typic Dystrochrept), and Paulding clay (very fine, illitic, nonacid, mesic, Typic Haplaquept) at a rate of 25% by weight of sludge to soil. The mixtures were incubated in a greenhouse and samples were taken at 1, 6, 12, and 20 wk and analyzed for: bulk and particle densities; water retention at 0, −5.9, −33, and −1500 kPa matric potentials; saturated hydraulic conductivity (Ks); water‐stable aggregates; shrinkage; Atterberg limits; and pocket penetrometer resistance. Results showed that the presence of olestra in sewage sludge at concentrations as high as 6% by weight should not exhibit any long‐term effects on these soil physical properties.
Threshold Application Rates of Wood Ash to an Acidic Forest Soil
Authors: Kahl Jeffrey S. , Fernandez Ivan J. , Rustad Lindsey E. , Peckenham John
Published: July 2010

Changes in soil and soil solution chemistry were studied for 2 yr after application of wood ash to an acidic forest Spodosol. Application rates to four 50 m2 plots were: 0 (control), 6, 13, and 20 Mg CaCO3 equivalents per hectare (Mg ha−1). In soil solution, the 13 and 20 Mg ha−1 treatments caused large but generally transient increases in base cations, pH, and anions. At 20 Mg ha−1, solution concentrations of H, acid neutralizing capacity (ANC), K, and SO4 remained elevated for 20 mo. There was minimal response in soil solutions at 6 Mg ha−1, suggesting that this rate may represent a threshold below which there is only minor response in soil solution chemistry. Loss of soil N into soil solution (as NO3) at the two higher application rates may have decreased available‐N in the already N‐limited soil. In the O horizon, all treatments resulted in increased pH and higher exchangeable Ca, K, Mg, CEC, and percent base saturation; Mn and Al decreased. In the B horizon, exchangeable Ca, K, Mg, and percent base saturation were higher than in the control. Responses in soil chemistry were not generally proportional to the ash application rate. Furthermore, the responses in soil chemistry at different application rates were generally not distinguishable from each other after 25 mo. The treatment rate of 6 Mg ha−1 ash was sufficient to favorably alter soil exchange chemistry, without seriously affecting solution chemistry. Above 6 Mg ha−1, soil exchange sites were unable to buffer ash amendments, resulting in substantial changes in solution chemistry.