bluuebunny/crossref_metadata_2025_split huggingface dataset:
Acidic Deposition and Tree Growth: II. Assessing the Role of Climate in Recent Growth Declines
Authors: LeBlanc David C. , Raynal Dudley J. , White Edwin H. 
Published: July 2010

AbstractDetailed stem analysis was used to measure historical growth of three coniferous tree species assumed to represent a wide range of susceptibility to potential acidic deposition effects on cation leaching. Sample trees were growing on an outwash plain in even‐aged monoculture plantations with similar stand histories and soils. Stepwise multiple regression was used to assess relationships between observed variations in growth and climatic variables. The ring‐number sequence, a relative measure of historical tree growth that did not require standardization, was particularly useful in analyses of growth‐environment relationships for young trees that exhibit consistent apical growth. Species/site groups assumed to be more susceptible to acidic deposition effects exhibited significant decreases in growth after 1960, but these decreases were correlated with climatic variables. Growth‐climate relationships derived for the pre‐1960s period did not predict decreases in tree growth observed during the mid‐1960s and late‐1970s, indicating a lack of time stability in growth‐climate relationships. This may be due to many factors, including maturation, climatic anamolies, and/or acidic deposition effects. This correlational study can not establish cause‐and‐effect relationships between tree growth and climate or acidic deposition. Independent confirmation and studies of the physiological mechanisms involved are needed to substantiate these results.
Effect of Municipal Solid Waste Leachate Composition on Zinc Migration through Soils
Authors: Boyle M. , Fuller W. H. 
Published: July 2010

AbstractThe relative impact of adjusting two main constituents of municipal solid waste (MSW) leachate, total organic carbon (TOC), and total soluble salts (TSS) on Zn migration through soils was evaluated. Four Zn‐enriched leachates of different TOC and TSS composition were perfused through five soils. The effluents from the 20 soil columns were collected and analyzed for the presence of Zn. Solution displacement continued until the concentration of the Zn in the effluent equaled that of the influent (100 mg L−1). In general, higher TOC and TSS levels in the leachate facilitated the migration of Zn through soil. The soil properties associated with Zn retention were, in order of importance, surface area, cation exchange capacity (CEC), and percent clay content. The TOC and TSS content of the MSW leachate studied were found to be more important in determining Zn attenuation behavior than soil characteristic.
Plant Exposure Chambers for Study of Toxic Chemical‐Plant Interactions
Authors: McFarlane J. Craig , Pfleeger Thomas 
Published: July 2010

AbstractChambers for the study of plant uptake and phytotoxicity of toxic, radio‐labeled chemicals are described. The chambers are designed to meet the criteria of continuously stirred tank reactors while providing containment for toxic chemical. They are computer managed and operated within a controlled environment room. Besides providing controlled conditions within the contained spaces, continuous measurements are made of various environmental parameters and plant transpiration, net photosynthesis, and dark respiration in up to 18 separate chambers.
Plant Availability and Uptake of Molybdenum as Influenced by Soil Type and Competing Ions
Authors: Smith C. , Brown K. W. , Deuel L. E. 
Published: July 2010

AbstractIrrigation has been proposed as a possible disposal method for large quantities of water having high concentrations of Mo (5–100 mg L−1) resulting from mining and reclamation activities. To assess this possibility, laboratory and greenhouse experiments were conducted to evaluate the influence of competing ions in the soil solution on the relationship between the sorption of Mo by soils and Mo uptake by grass. Laboratory experiments assessed Mo sorption by Edroy clay (Vertic Haplaquoll), Olmos loamy sand (Petrocalcic Calciustoll), and Randado sandy loam (Ustollic Paleargid). Soil treatments included 1, 5, 10, 20, 50, and 100 mg Mo L−1 added as ammonium molybdate in solutions of 0, 167, 333, and 500 mg L−1 concentrations of Cl− and 0, 226, 451, and 677 mg L−1 concentrations of SO2−4 salts. Sorption data fit the Freundlich isotherm. The Olmos soil had the highest CaCO3 content and sorbed the most Mo. The Edroy soil had the lowest pH and sorbed the least Mo. The presence of Cl− in solution increased Mo sorption, while SO2−4 reduced Mo sorption in all three soils. In the greenhouse study, soils were treated with 0, 6.5, 13.0, and 26.0 mg Mo kg−1 soil; 167, 334, and 501 mg Cl kg−1 soil; and cropped with bermudagrass, Cynodon dactylon (L.) Pers. No toxic symptoms or yield decreases were noted as a result of Mo or salt additions. Plants grown in soil containing 26.0 mg Mo kg−1 accumulated up to 600 mg Mo kg−1 dry matter and would be toxic to ruminants. The Mo concentrations in grass grown on the three soils were ranked from highest to lowest as Edroy > Randado > Olmos. Chloride addition to the soil had no significant (P <0.05) effect on bermudagrass Mo content. Both the concentration of Mo in the vegetation and the amount of Mo taken up by the vegetative cover were well correlated (r2 = 0.73 and 0.83, respectively) with the equilibrium solution Mo in the soil as calculated from the sorption isotherms. Thus, the results indicate that there is a strong relationship between the laboratory sorption data and the equilibrium solution Mo in the soil and that grass grown on soil irrigated with waters high in Mo may reach levels that are expected to be toxic to animals.
Evaluation of Pesticide Groundwater Pollution Potential from Standard Indices of Soil‐Chemical Adsorption and Biodegradation
Authors: Jury William A. , Focht Dennis D. , Farmer Walter J. 
Published: July 2010

AbstractA mathematical screening model of the pesticide leaching process is used to estimate the potential for a pesticide to reach groundwater at significant concentrations. The model assumes steady water flow, equilibrium linear adsorption, and depth‐dependent first‐order biodegradation and predicts groundwater travel times and residual concentrations that depend on soil and environmental conditions as well as pesticide adsorption and decay constants. When groundwater protection is expressed as a condition that the residual undegraded pesticide mass remaining below the surface layer of soil must be less than a specified fraction of the initial mass added in a pulse application at the surface, the model prediction is shown to reduce to a linear inequality between the organic C partition coefficient Koc and the biochemical half‐life, τ. The screening model is illustrated on 50 pesticides and two scenarios representing low and high potential for groundwater contamination. The calculations reveal a significant dependence on site‐specific soil and environmental conditions, suggesting that regulations restricting pesticide use should take soil and management factors as well as chemical properties into account when screening for groundwater pollution potential.
Pesticide Contamination of Groundwaters in the Mahantango Creek Watershed
Authors: Pionke H. B. , Glotfelty D. E. , Lucas A. D. , Urban J. B. 
Published: July 2010

AbstractWaters from 20 wells in a primarily agricultural Pennsylvania watershed were analyzed for the most heavily and extensively applied pesticides as determined by farm survey. Those analyzed were atrazine, metolachlor, cyanazine, alachlor, terbufos, chlorpyrifos, fonofos, and carbofuran. No metolachlor, alachlor, terbufos, chlorpyrifos, fonofos, or carbofuran were detected. However, atrazine concentrations ranging from 13 to 1110 ng/L were found in 14 of the 20 wells. These findings suggest widespread atrazine contamination of the groundwaters, but at extremely low concentrations. Cyanazine was found above trace concentrations in one well. Although there was only one record of application, simazine was found in seven wells within the range of 10 to 170 ng/L. The degree and spatial distribution of atrazine contamination depended mostly on the frequency and distribution of corn production. The highest atrazine concentrations were associated mostly with continuous corn production. Aquifer rock type, depth to water table, and the degree of recharge short‐circuiting estimated from PO4 contamination of groundwater, were concluded not to be important factors. Generally, Cl provided a better index of atrazine contamination than did NO3 because extensive denitrification occurred in several wells. The probability of atrazine being found above the minimum detection limit was high when Cl exceeded 3 mg/L or NO3‐N exceeded 4 mg/L.
Biogeochemical Control on Metal Distribution and Accumulation in Louisiana Sediments
Authors: Feijtel T. C. , DeLaune R. D. , Patrick W. H. 
Published: July 2010

AbstractMetal accumulation rates were determined from sedimentation rates and the distribution of 137Cs and total metal content in cores collected from freshwater, brackish, and saltwater bay bottoms in Barataria Basin, LA. Vertical accretion rates ranged from 0.65 cm/yr in the northern freshwater part of the basin up to 1.1 cm/yr in the lower saline estuary. Metal sedimentation and accumulation rate estimates along this salinity gradient indicated that metals were concentrated by a factor of two to four in the saline end‐member. Manganese, however, exhibited an estimated depletion of 1.95 g/(m2 yr) in the lower part of the basin, due to its postdepositional mobility. A principal component and regression analysis of total metal distribution showed that the metal content could be predicted by the C content of the substrate (R = 0.89**; significant at the 0.01 probability level). This suggested the sedimentation of metal‐rich organic matter, most likely originating from adjacent marshes. Clay and silt content were insignificant as predictor variables. In the subsurface layer (0–4 cm), 18% of the variability in Fe and 27% in the variability in Mn content were attributed to redox processes, and were adequately predicted by the redox potential of the sediment (R = 0.60*; significant at the 0.05 probability level). Partial metal partitioning in soluble, exchangeable, and reducible fractions indicated that Fe, Al, Cu, Zn, Pb, and Cd held in the water soluble and exchangeable phase represented a minor part of the total metal content. However, water soluble plus exchangeable Mn accounted for 19,10, and 1% of the total Mn in freshwater, brackish, and saltwater environments, respectively. Iron and manganese oxides were found to scavenge metals to 50% of the total heavy metal content.
Influence of Soil Animals and Metals on Decomposition Processes: A Microcosm Experiment
Authors: Bengtsson Goran , Berden Maria , Rundgren Sten 
Published: July 2010

AbstractMetal pollution may reduce both the density and diversity of litter‐and mor‐living soil invertebrates. The consequences of this reduction for decomposition processes in coniferous forest soils were studied in a laboratory microcosm experiment, where the influence of soil fauna and metals were examined. Soil columns were prepared with litter, mor, and mineral soil, and the indigenous microorganisms from two field sites approximately 300 and 8000 m from a brass mill. The columns were used during a 10‐wk experiment with enchytraeids and microarthropods added. Presence of animals increased C and N mineralization and enhanced leaching of dissolved organic C and nutrients by 20 to 30%. All of the reduced mass lost due to metal pollution and 20 to 35% of the reduction in leachate quantities of organic C and inorganic nutrients could be explained by reduced animal activity. The calculated decomposition rate constants predicted a delay in decomposition in the metal‐polluted soil by a factor of 10. With five replicates, an 18% difference in mass lost due to a doubling of the background concentration of metals could be detected by the microcosm method with a probability of 0.90.
Fly Ash and Lime Amendment of Acidic Coal Spoil to Aid Revegetation
Authors: Taylor E. M. , Schuman G. E. 
Published: July 2010

AbstractA greenhouse study was conducted to evaluate the effect of fly ash (0, 10, 20, 30, and 40 g kg−1 of spoil) and agricultural lime (0, 10, 20, 40, and 80 g kg−1 of spoil) on ameliorating the low pH of acidic coal mine spoils. Topsoil depths of 0, 10, and 20 cm placed over the spoil were also evaluated. Two crops of barley (Hordeum vulgare L.) were grown to evaluate effects of the amendments and topsoil on aboveground plant biomass, root biomass and distribution, and element content of the vegetation. All levels of lime and fly ash significantly increased the spoil pH, aboveground plant biomass, and root biomass. Topsoil placement over the spoil also generally increased plant biomass. Root growth in untreated spoil was limited to the depth of topsoil. However, when the spoil was amended with either fly ash or lime root growth occurred throughout the material. Fly ash and lime did not cause elemental toxicities to the plants, except for B. Although visual B toxicity symptoms and elevated levels of plant B were evident, no reduction in plant biomass occurred. The results indicate that fly ash is a feasible alternative to lime for treating acidic coal spoils in the region.
Tungsten Content of Soils, Plants, and Sewage Sludges in Iowa
Authors: Fu M. H. , Tabatabai M. A. 
Published: July 2010

AbstractInformation on the W content in environmental matrices is desired. Because of the antagonistic effect of W on Mo nutrition of plants and microorganisms, this study was conducted to assess the concentration of W in soils, plant materials, and sewage sludges in Iowa. Results showed that the total W in 18 soils ranged from 0 to 2 mg kg−1, with mean and median values of 0.89 and 0.88 mg kg−1, respectively. The corresponding values for 22 plant materials ranged from 0 to 0.35 mg kg−1, with mean and median values of 0.18 and 0.17 mg kg−1. Analysis of 44 sewage sludge samples from different wastewater‐treatment plants in Iowa showed that the concentration of this element varied from 0.5 to 62 mg kg−1, with mean and median values of 4.3 and 2.2 mg kg−1, respectively.
Nutritional Factors that May Influence Bioavailability of Cadmium
Authors: Fox M. R. Spivey 
Published: July 2010

AbstractCadmium accumulates slowly in the human body and a critically high level in the kidney can cause damage to the proximal renal tubule. Loss of Ca in the urine then contributes to extensive skeletal mineral loss. The bioavailability of Cd to animals and humans can be markedly affected by nutritional status and dietary intakes of essential and other nutrients. In general, deficiencies and excesses of interacting nutrients exacerbate and protect, respectively, against the adverse effect of Cd. These effects on bioavailability occur primarily via changes in intestinal absorption, although accelerated uptake by the kidney sometimes occurs. The chemical form of Cd that is consumed experimentally can also modify response. Many aspects of the relationships between Cd and nutrients are incompletely understood. From studies of population groups with high Cd intakes from certain foods, it appears that consumption of an adequate diet protects markedly againsthe adverse effects of Cd.
Sources of Nitrogen and Phosphorus in an Estuary of the Chesapeake Bay
Authors: Kunishi H. M. 
Published: July 2010

AbstractThis study examined the contribution of agriculture to the nutrient (N and P) concentrations in the Wye River, an estuarine tributary the Chesapeake Bay. The river drains a watershed that is devoted mainly to farming and is devoid of any sources of municipal and industrial wastes. Water samples were analyzed for NO3‐N + NO2‐N and molybdate‐reactive P (MRP). The concentrations of these forms nutrients were then examined in relation to sampling site, sample salinity, and time of year. Freshwater entering the river (brackish) from the watershed contained consistently high concentrations of NO3‐N (about 4 mg L−1) and low concentrations of PO4‐P (about 40 µg L−1). Once these nutrients entered the estuarine part of the river, however, the concentrations of NO3‐N decreased to low levels within a short distance (500–700 m) from the point of riverine discharge, through both dilution with brackish water and apparent microbial action. The concentrations of MRP increased markedly through release from within estuary sources. Concomitantly, the estuary released large quantities of NH4. The estuary itself, therefore, was the immediate major source of N (as NH4) and P.
Minesoil Property Effects on the Height of Ten‐Year‐Old White Pine
Authors: Torbert J. L. , Tuladhar A. R. , Burger J. A. , Bell J. C. 
Published: July 2010

AbstractThirty‐four 10‐yr‐old white pines (Pinus strobus L.) growing on reclaimed minesoils in Virginia were selected to evaluate the effects of selected minesoil properties on tree growth. A 1‐m deep backhoe pit was dug at the base of each tree to determine rooting depth, and surface soil samples (0–10 cm) were collected for analysis of selected physical and chemical properties. Multiple regression analysis was used to model the combined effects of minesoil properties on tree height. The minesoil variable that had the greatest influence on tree growth was rooting volume index, defined as depth to a restrictive layer times the soil‐sized fraction (%) of the surface 10 cm. The next most influential minesoil property that affected height was soluble salt content; an inverse relationship existed between tree height and electrical conductivity of a 1:5 soil/water extract. A linear regression equation describing white pine site index (SI50) as a function of the square root of depth to a restrictive layer was highly significant.
Radiochemical Analysis of Phosphorus Exchange Kinetics between Sediments and Water under Aerobic Conditions
Authors: Furumai H. , Ohgaki S. 
Published: July 2010

AbstractAdsorption‐desorption reactions of P by lake sediments, Lake Kasumigaura, Japan, were studied using radioisotope 32P inorganic phosphate. Exchange rates and amounts of exchangeable P in sediments were measured in aerobic sediments‐water batch systems under different pH and P concentration conditions. Exchangeable P ranged from 6 to 43% of the total P in the indigenous sediments. Increasing pH induced P desorption from sediment. The relationship between the concentration in water and the amount of exchangeable P could be explained by the Langmuir equilibrium model. However, the Langmuir rate equation cannot describe the kinetics of whole exchange reactions. The adsorption‐desorption reaction was composed of an exchange reaction and a slow adsorbed‐reaction. The exchange reaction has two phases—very rapid reaction and a Langmuir‐type reaction.
Forest Harvest and Site Preparation Effects on Erosion and Sedimentation in the Ouachita Mountains
Authors: Miller E. L. , Beasley R. S. , Lawson E. R. 
Published: July 2010

AbstractSoil erosion and sedimentation effects of three silvicultural treatments—clearcutting, selection cutting and no disturbance (control)—were compared in a replicated small watershed study conducted in the Ouachita Mountains of Arkansas on shallow soils derived from sandstones and shales. Clearcutting significantly increased annual sediment yields over selection and control treatments in 1981, the first year, after treatment but not in 1982 or 1983. Clearcut to control sediment yield ratios were 20:1, 6:1, and 2.6:1 in 1981, 1982, and 1983, respectively. First‐year sediment losses from clearcuts averaged 237 kg ha−1. Stream channels were stable, but they still may have been the primary source of the sediment losses. Erosion following harvest and site preparation did not exceed estimates of long‐term soil formation rates. Longterm soil losses were projected to average 70 kg ha−1 yr−1 over a 35‐yr rotation period with clearcutting while control rates were projected to average 50 kg ha−1 yr−1. A comparison of soil losses measured in this study with baseline rates and estimated soil loss tolerances suggests site productivity need not be threatened by silviculturally induced soil erosion. Suspended solids levels of stormflow were less than 100, 50, and 20 mg L−1 at least 99, 98, and 97% of the time, respectively, across treatments. Only at the 10 mg L−1 level was there a significant total suspended solids time differential in watershed stormflow between clearcut or selection cut and control treatments.
Retention of Cadmium by Several Soils of the Southeastern United States
Authors: King Larry D. 
Published: July 2010

AbstractSince significant entry of Cd into the food chain is undesirable, soil properties important in reducing plant availability of Cd must be identified. Solubility of applied Cd in various extraction solutions is one estimate of plant availability. Cadmium nitrate was applied at rates supplying up to 1.25 mmol Cd kg−1 (140 mg kg−1) to soil from the A horizons and some B horizons of 10 mineral and three organic soils. The treated soils were incubated at 20 °C and at the end of 2, 4, and 8 weeks samples were withdrawn and extracted with 1 M KCl, Mehlich 1 (M1), and 0.2 M (NH4)2C2O4 [AO]. Length of incubation had no effect on the quantity of Cd removed by the extractants (extractability). Extractability was related linearly to Cd application rate but the effect of soil type on slope (extractable Cd/applied Cd) was more pronounced with KCl (110% variation in slopes) and AO (270%) than with M1 (27%). At the 1.25 mmol Cd kg−1 rate, KCl‐extractable Cd decreased with increasing pH but differences among soils were large. Stepwise multiple regression was performed using sand; silt; clay; pH; cation exchange capacity (CEC); exchangeable cations; organic matter; dithionite‐extractable Al and Fe; and AO‐extractable Al, Fe, and Mn as independent variables. Exchangeable Ca and pH were important soil properties related to extractability with the three extractants but values of R2 were < 0.8 even for three‐variable models. Since pH was the dominant factor, the data were grouped into pH increments of 0.5 and regression repeated. Exchangeable Ca, CEC, and dithionite‐extractable Al were important factors related to extractability, but values of R2 were < 0.6. Overall, the ability to estimate extractability from basic soil properties was low.
Formation of a Cemented Subsurface Horizon in Sulfidic Minewaste
Authors: McSweeney K. , Madison F. W. 
Published: July 2010

AbstractIn the early 1900s, Pb‐Zn ores in southwest Wisconsin were roasted for metal extraction. In the process, Fe‐bearing minerals were converted to a magnetic state for separation; metallic oxides were recovered and wastes consisting of about 30% Fe and 15% S, as well as numerous minor constituents, were deposited on the land surface in close proximity to the processing plants. Although the waste materials remain unvegetated today, significant changes have occurred in their mineralogical composition, which are reflected in the formation of discrete horizons. Micromorphological techniques were used to determine the pore space relationships of the unconsolidated material and the elemental and mineral distribution in the various horizons. Mineralogical transformations have been documented, which are largely dictated by the hydrology, porosity, and redox chemistry of the waste. The transformations include subsurface precipitation of mainly gypsum and Fe oxides and hydroxides in inter‐aggregate pores and mainly hydrated Fe‐sulfates such as copiapite and kalinite within intra‐aggregate pores. The net result is a dense, cemented horizon, which probably has a low permeability. The presence of this cemented layer has important implications for developing reclamation strategies, because it may form a potential barrier to transport of pollutants to the groundwater.