bluuebunny/crossref_metadata_2025_split huggingface dataset:
Equilibrium Sampling Used to Monitor Malodors in a Swine Waste Lagoon
Authors: Loughrin John H. , Lovanh Nanh , Mahmood Rezaul 
Published: January 2008

AbstractThe concentrations of malodorous compounds in a 0.4‐ha anaerobic lagoon that received waste from approximately 2000 sows were monitored during the late summer to late fall of 2006 to gain insight into the factors influencing their concentrations. Selected malodorous compounds were measured by the use of equilibrium samplers consisting of submersible stir plates and stir bar sorbtive sampling with polydimethylsiloxane‐coated magnetic stir bars. During the same period, air and water temperatures, suspended solids, total organic carbon and nitrogen content, and wastewater pH were recorded. Concentrations of malodorous compounds were higher at the surface of the lagoon than at the middle or bottom of the lagoon. Skatole concentration, for instance, averaged 54, 24, and 38 μg L−1near the surface, in the middle, and at the lowest sampling depths, respectively. While the lagoon was being pumped down during field application of wastewater, concentrations of malodorous compounds fluctuated widely, increased 16‐fold as compared with the sampling period before pumping, and continued to increase as fall progressed and temperatures cooled. Suspended solids, volatile suspended solids, and total organic carbon increased near the bottom of the lagoon during this same period. The increases in the concentrations of malodorous compounds in the wastewater during the fall could have been due to a combination of several factors. These factors include reduced degradation by lagoon bacteria, less wind stripping of volatile compounds from the lagoon surface due to lowering of the lagoon surface after crop application, and/or reduced evaporation of malodorous compounds due to falling temperatures.
Water Quality Effects of Clearcut Harvesting and Forest Fertilization with Best Management Practices
Authors: McBroom Matthew W. , Beasley R. Scott , Chang Mingteh , Ice George G. 
Published: January 2008

AbstractNine small (2.5 ha) and four large (70–135 ha) watersheds were instrumented in 1999 to evaluate the effects of silvicultural practices with application of best management practices (BMPs) on stream water quality in East Texas, USA. Two management regimes were implemented in 2002: (i) conventional, with clearcutting, herbicide site preparation, and BMPs and (ii) intensive, which added subsoiling, aerial broadcast fertilization, and an additional herbicide application. Watershed effects were compared with results from a study on the same small watersheds in 1981, in which two combinations of harvesting and mechanical site preparation without BMPs or fertilization were evaluated. Clearcutting with conventional site preparation resulted in increased nitrogen losses on the small watersheds by about 1 additional kg ha−1 each of total Kjeldahl nitrogen (TKN) and nitrate‐nitrogen (NO3–N) in 2003. First‐year losses were not significantly increased on the large watershed with a conventional site preparation with BMPs. Fertilization resulted in increased runoff losses in 2003 on the intensive small watersheds by an additional 0.77, 2.33, and 0.36 kg ha−1 for NO3–N, TKN, and total phosphorus, respectively. Total loss rates of ammonia nitrogen (NH4–N) and NO3–N were low overall and accounted for only ∼7% of the applied N. Mean loss rates from treated watersheds were much lower than rainfall inputs of about 5 kg ha−1 TKN and NO3–N in 2003. Aerial fertilization of the 5‐yr‐old stand on another large watershed did not increase nutrient losses. Intensive silvicultural practices with BMPs did not significantly impair surface water quality with N and P.
Bioassays with Unicellular Algae: Deviations from Exponential Growth and Its Implications for Toxicity Test Results
Authors: Altenburger Rolf , Schmitt‐Jansen Mechthild , Riedl Janet 
Published: January 2008

AbstractGrowth assays with unicellular green algae are an established tool in ecotoxicological effect assessment for chemicals and environmental samples. From an ecological perspective it seems appropriate to use the growth rate as a process variable rather than a measure of biomass gain for calculating inhibitory effects of contaminants. The notion of simple exponential growth for the description of the population increase in undisturbed suspension cultures of unicellular green algae, however, seems to be an oversimplification. Experimental findings describe the increase in biomass, cell number, the development of cell volume distributions of populations, and the relationship between cell size and chlorophyll content for individual cells over one generation at a time resolution of 2‐h intervals. It was observed that algal populations of Desmodesmus subspicatus show a time pattern of cell size growth; the average cell volume increases about sixfold, without corresponding increase in population size. This is followed by a distinct cell division phase with little gain in biomass. This synchronous growth behavior despite continuous illumination may be explained by the multiple fission characteristic of unicellular green algae which is an adaptation to cyclic light–dark changes in the environment. It might be controlled by an independent cell cycle clock. For routine regulatory testing fluorescence‐based measurements rather than cell counting minimizes the confounding effect on toxicity determination. For investigations of time‐dependent effects, e.g., by pulsed exposure, an alternative mechanistically based growth function for unicellular algae is proposed that accommodates for the observed growth pattern.
Hydro‐geochemical Aspects of Mediterranean Temporary Ponds in Western Crete
Authors: Stamati Fotini , Nikolaidis Nikolaos , Dimitriou Elias , Koussouris Theodore 
Published: January 2008

AbstractThe hydrologic and geochemical conditions that prevail in Mediterranean temporary ponds (MTPs), create a unique environment for many rare and endangered species. Mediterranean temporary ponds are habitats of high ecological value, which are vulnerable to imminent climatic changes, as well as to human activities. This article examines the hydrology and the nitrogen and phosphorous geochemical cycles of four MTPs in Crete. Field and laboratory studies provided the necessary information for the development of a conceptual understanding of the hydrologic and biogeochemical processes that affect the fate of nitrogen and phosphorous in these MTPs. Their hydrology was driven by deposition, infiltration, and evaporation. The hydroperiod of the ponds varied between 40 and 160 d. Mineralization and nutrient release capacity experiments illustrated the significant role that MTP sediments played in enhancing the geochemistry of the aqueous phase. Such ecosystem functions (i.e., mineralization, nutrient release) exhibited high variability among MTPs necessitating site‐specific studies with immediate implications to management. It is very important to understand the local hydrogeochemical and climatic conditions to ensure appropriate environmental measures for their management and conservation.
Empirical Models Based on the Universal Soil Loss Equation Fail to Predict Sediment Discharges from Chesapeake Bay Catchments
Authors: Boomer Kathleen B. , Weller Donald E. , Jordan Thomas E. 
Published: January 2008

AbstractThe Universal Soil Loss Equation (USLE) and its derivatives are widely used for identifying watersheds with a high potential for degrading stream water quality. We compared sediment yields estimated from regional application of the USLE, the automated revised RUSLE2, and five sediment delivery ratio algorithms to measured annual average sediment delivery in 78 catchments of the Chesapeake Bay watershed. We did the same comparisons for another 23 catchments monitored by the USGS. Predictions exceeded observed sediment yields by more than 100% and were highly correlated with USLE erosion predictions (Pearson r range, 0.73–0.92; p < 0.001). RUSLE2‐erosion estimates were highly correlated with USLE estimates (r = 0.87; p < 001), so the method of implementing the USLE model did not change the results. In ranked comparisons between observed and predicted sediment yields, the models failed to identify catchments with higher yields (r range, –0.28–0.00; p > 0.14). In a multiple regression analysis, soil erodibility, log (stream flow), basin shape (topographic relief ratio), the square‐root transformed proportion of forest, and occurrence in the Appalachian Plateau province explained 55% of the observed variance in measured suspended sediment loads, but the model performed poorly (r2 = 0.06) at predicting loads in the 23 USGS watersheds not used in fitting the model. The use of USLE or multiple regression models to predict sediment yields is not advisable despite their present widespread application. Integrated watershed models based on the USLE may also be unsuitable for making management decisions.
Reduction of Pathogen Indicator Organisms in Dairy Wastewater Using an Ecological Treatment System
Authors: Morgan Jennifer A. , Hoet Armando E. , Wittum Thomas E. , Monahan Clifton M. , Martin Jay F. 
Published: January 2008

AbstractEcological treatment systems can provide a sustainable, plant‐based alternative to traditional wastewater treatment. One factor essential to the success of these systems is ensuring their ability to reduce coliform concentrations in wastewater. Wastewater is the primary source of fecal contamination in aquatic ecosystems, containing total and fecal coliforms on the order of 108–1010 and 107–109 CFU L−1, respectively. This study assessed the ability of an ecological treatment system to reduce concentrations of total coliforms and Escherichia coli from dairy wastewater. Low strength wastewater was pumped into the system during July of 2005 and high strength in September 2005. Wastewater passes through a series of anaerobic, aerobic, and clarifier reactors and wetland cells before exiting the system. Regardless of wastewater strength, average total coliform and E. coli concentrations were consistently reduced by at least 99% from influent to effluent, with the majority of the reduction (76%) occurring in the first two reactors. Relationships between internal concentrations of solids and coliforms indicated that increased reduction of solids may further reduce coliform concentrations. Although U.S. Environmental Protection Agency discharge requirements for E. coli were not always met, the substantial reductions achieved indicate that ecological treatment systems have the potential to successfully reduce coliforms in wastewater to meet discharge limits. The results from this study will be used to guide design and management of future ecological treatment systems, so that larger and more consistent coliform reductions can be achieved.
Effect of Liquid Swine Manure Rate, Incorporation, and Timing of Rainfall on Phosphorus Loss with Surface Runoff
Authors: Allen Brett L. , Mallarino Antonio P. 
Published: January 2008

AbstractExcessive manure phosphorus (P) application increases risk of P loss from fields. This study assessed total runoff P (TPR), bioavailable P (BAP), and dissolved reactive P (DRP) concentrations and loads in surface runoff after liquid swine (Sus scrofa domesticus) manure application with or without incorporation into soil and different timing of rainfall. Four replicated manure P treatments were applied in 2002 and in 2003 to two Iowa soils testing low in P managed with corn (Zea mays L.)–soybean [Glycine max (L.) Merr.] rotations. Total P applied each time was 0 to 80 kg P ha−1 at one site and 0 to 108 kg P ha−1 at the other. Simulated rainfall was applied within 24 h of P application or after 10 to 16 d and 5 to 6 mo. Nonincorporated manure P increased DRP, BAP, and TPR concentrations and loads linearly or exponentially for 24‐h and 10‐ to 16‐d runoff events. On average for the 24‐h events, DRP, BAP, and TPR concentrations were 5.4, 4.7, and 2.2 times higher, respectively, for nonincorporated manure than for incorporated manure; P loads were 3.8, 7.7, and 3.6 times higher; and DRP and BAP concentrations were 54% of TPR for nonincorporated manure and 22 to 25% for incorporated manure. A 10‐ to 16‐d rainfall delay resulted in DRP, BAP, and TPR concentrations that were 3.1, 2.7, and 1.1 times lower, respectively, than for 24‐h events across all nonincorporated P rates, sites, and years, whereas runoff P loads were 3.8, 3.6, and 1.6 times lower, respectively. A 5‐ to 6‐mo simulated rainfall delay reduced runoff P to levels similar to control plots. Incorporating swine manure when the probability of immediate rainfall is high reduces the risk of P loss in surface runoff; however, this benefit sharply decreases with time.
Environmental Risk Assessment of Genetically Engineered Herbicide‐TolerantZoysia japonica
Authors: Bae T. W. , Vanjildorj E. , Song S. Y. , Nishiguchi S. , Yang S. S. , Song I. J. , Chandrasekhar T. , Kang T. W. , Kim J. I. , Koh Y. J. , Park S. Y. , Lee J. , Lee Y.‐E. , Ryu K. H. , Riu K. Z. , Song P.‐S. , Lee H. Y. 
Published: January 2008

AbstractHerbicide‐tolerantZoysiagrass (Zoysia japonicaSteud.) has been generated previously throughAgrobacterium tumefaciens‐mediated transformation. The genetically modified (GM)Zoysiagrass survived Basta spraying and grew to maturity normally while the wild‐type (WT) grass stopped growing and died. GMZoysiagrass will permit more efficient weed control for various turf grass plantings such as home lawns, golf courses, and parks. We examined the environmental/biodiversity risks of herbicide‐tolerant GMZoysiabefore applying to regulatory agencies for approval for commercial release. The GM and WTZoysiagrass' substantial trait equivalence, ability to cross‐pollinate, and gene flow in confined and unconfined test fields were selectively analyzed for environmental/biodiversity effects. No difference between GM and WTZoysiagrass in substantial traits was found. To assess the potential for cross‐pollination and gene flow, a non‐selective herbicide, Basta, was used. Results showed that unintended cross‐pollination with and gene flow from GMZoysiagrass were not detected in neighboring weed species examined, but were observed in WTZoysiagrass (on average, 6% at proximity, 1.2% at a distance of 0.5 m and 0.12% at a radius of 3 m, and 0% at distances over 3 m). On the basis of these initial studies, we conclude that the GMZoysiagrass generated in our laboratory and tested in the Nam Jeju County field does not appear to pose a significant risk when cultivated outside of test fields.
Phosphorus and Nitrogen Sorption to Soils in the Presence of Poultry Litter‐Derived Dissolved Organic Matter
Authors: Goyne Keith W. , Jun Hee‐Joong , Anderson Stephen H. , Motavalli Peter P. 
Published: January 2008

AbstractTwo environmental aspects associated with land application of poultry litter that have not been comprehensively evaluated are (i) the competition of dissolved organic matter (DOM) and P for soil sorption sites, and (ii) the sorption of dissolved organic nitrogen (DON) relative to inorganic nitrogen species (e.g., NO3− and NH4+) and dissolved organic carbon (DOC). The competition between DOM and P for sorption sites has often been assumed to increase the amount of P available for plant growth; however, elevating DOM concentrations may also increase P available for transport to water resources. Batch sorption experiments were conducted to (i) evaluate soil properties governing P sorption to benchmark soils of Southwestern Missouri, (ii) elucidate the impact of poultry litter‐derived DOM on P sorption, and (iii) investigate DON retention relative to inorganic N species and DOC. Soils were reacted for 24 h with inorganic P (0–60 mg L−1) in the presence and absence of DOM (145 mg C L−1) using a background electrolyte solution comparable to DOM extracts (I = 10.8 mmol L−1; pH 7.7). Soil P sorption was positively correlated with metal oxide (r2 = 0.70) and clay content (r2 = 0.79) and negatively correlated with Bray‐1 extractable P (r2 = 0.79). Poultry litter‐derived DOM had no significant negative impact on P sorption. Dissolved organic nitrogen was preferentially removed from solution relative to (NO3−–N + NO2−–N), NH4+–N, and DOC. This research indicates that poultry litter‐derived DOM is not likely to enhance inorganic P transport which contradicts the assumption that DOM released from organic wastes increases plant‐available P when organic amendments and fertilizer P are co‐applied. Additionally, this work demonstrates the need to further evaluate the fate and transport of DON in agroecosystem soils receiving poultry litter applications.
Ecological Effects after an Alum Treatment in Spring Lake, Michigan
Authors: Steinman Alan D. , Ogdahl Mary 
Published: January 2008

AbstractA whole‐lake alum treatment was applied to eutrophic Spring Lake during October and November 2005. Eight months later, an ecological assessment of the lake was performed and compared with data collected in 2003 and 2004. Field measurements showed reduced soluble reactive phosphorus (SRP) and total phosphorus (TP) concentrations in the water column the summer after the alum application, but chlorophyll levels and irradiance profiles were not significantly affected. Total macroinvertebrate density declined significantly in 2006 compared with 2004, with chaoborids and oligochaetes experiencing the greatest reductions. Internal phosphorus release rates, measured using sediment cores incubated in the laboratory, ranged from −0.052 to 0.877 mg TP m−2 d−1 under anaerobic conditions. These internal loading rates were significantly lower than those measured in 2003 at three out of four sites. Mean porewater SRP concentrations were lower in 2006 than in 2003, but this difference was statistically significant only under aerobic conditions. The NaOH‐extractable SRP fraction in the sediment was also significantly lower in 2006 compared with 2003, whereas the HCl‐extractable SRP sediment fraction showed the opposite pattern. Overall, these results indicate that the alum treatment effectively reduced internal P loading in Spring Lake. However, water column phosphorus concentrations remain high in this system, presumably due to high external loading levels, and may account for the high chlorophyll levels. An integrated watershed management approach that includes reducing internal and external inputs of P is necessary to address the cultural eutrophication of Spring Lake.
Phosphorus Sorbing Materials: Sorption Dynamics and Physicochemical Characteristics
Authors: Leader J. W. , Dunne E. J. , Reddy K. R. 
Published: January 2008

AbstractThe effectiveness of various management practices to reduce phosphorus (P) loss from soil to water can potentially be improved by using by‐product materials that have the capacity to sorb phosphorus. This study evaluated the P sorption and desorption potential, and the physicochemical characteristics of various phosphorus sorbing materials. Twelve materials were selected and P sorption potentials ranged between 66 and 990 mg kg−1 Iron, and calcium drinking water treatment residuals (DWTRs), a magnesium fertilizer by‐product, aluminum, and humate materials all removed substantial amounts of P from solution and desorbed little. Humate had the highest maximum P sorption capacity (Smax). Materials which had a low equilibrium P concentration (EPC0) and a high Smax included aluminum and humate by‐products. In a kinetic study, the Fe‐DWTR, Ca‐DWTR, aluminum, and magnesium by‐product materials all removed P (to relatively low levels) from solution within 4 h. Phosphorus fractionation suggests that most materials contained little or no P that was readily available to water. Sand materials contained the greatest P fraction associated with fulvic and humic acids. In general, materials (not Ca‐DWTR) and magnesium by‐product were composed of sand‐sized particles. There were no relationships between particle size distributions and P sorption in materials other than sands. The Ca‐ and Fe‐DWTR, and magnesium by‐product also contained plant nutrients and thus, may be desirable as soil amendments after being used to sorb P. Further, using Ca‐DWTRs and Fe‐DWTRs as soil amendments may also increase soil cation exchange and water holding capacity.
Phosphate Treatment of Firing Range Soils: Lead Fixation or Phosphorus Release?
Authors: Dermatas Dimitris , Chrysochoou Maria , Grubb Dennis G. , Xu Xuanfeng 
Published: January 2008

AbstractPhosphate treatment of lead (Pb)‐contaminated soils relies on the premise that Pb converts to the thermodynamically stable, insoluble mineral class of pyromorphites. Recent research showed that treatment performance is kinetically controlled and strongly dependent on soil pH; this study employed an acidic phosphate (P) form, monobasic calcium phosphate (MCP), to investigate treatment performance of Pb occurring in an alkaline‐buffered and an acidic firing range soil. The results of leaching, X‐ray powder diffraction (XRPD), and modeling analyses showed that P and Pb dissolution in the alkaline soil and transformation reactions were kinetically controlled, so that: (i) TCLP (toxicity characteristic leaching procedure) and SPLP (synthetic precipitation leaching procedure) results were poor to marginal even at high MCP dosages; (ii) brushite (Ca(HPO4)·2H2O) and cerussite (PbCO3) persisted in XRPD patterns; and, (iii) geochemical modeling failed to predict leaching and phase assemblages. In the acidic soil, Pb‐P reactions promoted further soil acidification, improved TCLP performance, and generated better agreement with the equilibrium‐based model; however, SPLP and modeling results showed that Pb concentrations could not be reduced below 15 μg/L mainly due to the low soil pH. The marginal or inadequate Pb immobilization was observed in both soils despite the elevated MCP dosages, which were well in excess of the pyromorphite stoichiometric ratio (P/Pb = 0.6). Additionally, P leaching concentrations and rates were extremely high (>300 mg/L), under both SPLP and deionized (DI) water extraction conditions, and as predicted by thermodynamic equilibrium. The performance and sustainability of phosphate‐based treatment therefore seem questionable.
Determination of Dominant Biogeochemical Processes in a Contaminated Aquifer‐Wetland System Using Multivariate Statistical Analysis
Authors: Báez‐Cazull Susan E. , McGuire Jennifer T. , Cozzarelli Isabelle M. , Voytek Mary A. 
Published: January 2008

AbstractDetermining the processes governing aqueous biogeochemistry in a wetland hydrologically linked to an underlying contaminated aquifer is challenging due to the complex exchange between the systems and their distinct responses to changes in precipitation, recharge, and biological activities. To evaluate temporal and spatial processes in the wetland‐aquifer system, water samples were collected using cm‐scale multi‐chambered passive diffusion samplers (peepers) to span the wetland‐aquifer interface over a period of 3 yr. Samples were analyzed for major cations and anions, methane, and a suite of organic acids resulting in a large dataset of over 8000 points, which was evaluated using multivariate statistics. Principal component analysis (PCA) was chosen with the purpose of exploring the sources of variation in the dataset to expose related variables and provide insight into the biogeochemical processes that control the water chemistry of the system. Factor scores computed from PCA were mapped by date and depth. Patterns observed suggest that (i) fermentation is the process controlling the greatest variability in the dataset and it peaks in May; (ii) iron and sulfate reduction were the dominant terminal electron‐accepting processes in the system and were associated with fermentation but had more complex seasonal variability than fermentation; (iii) methanogenesis was also important and associated with bacterial utilization of minerals as a source of electron acceptors (e.g., barite BaSO4); and (iv) seasonal hydrological patterns (wet and dry periods) control the availability of electron acceptors through the reoxidation of reduced iron‐sulfur species enhancing iron and sulfate reduction.