bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sorption and Stability of the Polycyclic Nitramine Explosive CL‐20 in Soil
Authors: Balakrishnan Vimal K. , Monteil‐Rivera Fanny , Gautier Mathieu A. , Hawari Jalal 
Published: June 2010

ABSTRACTThe polycyclic nitramine CL‐20 (2,4,6,8,10,12‐hexanitro‐2,4,6,8,10,12‐hexaazaisowurtzitane) is being considered for use as a munition, but its environmental fate and impact are unknown. The present study consisted of two main elements. First, sorption–desorption data were measured with soils and minerals to evaluate the respective contributions of organic matter and minerals to CL‐20 immobilization. Second, since CL‐20 hydrolyzes at a pH of >7, the effect of sorption on CL‐20 degradation was examined in alkaline soils. Sorption–desorption isotherms measured using five slightly acidic soils (5.1 < pH < 6.9) containing various amounts of total organic carbon (TOC) revealed a nonlinear sorption that increased with TOC [Kd (0.33% TOC) = 2.4 L kg−1; Kd (20% TOC) = 311 L kg−1]. Sorption to minerals (Fe2O3, silica, kaolinite, montmorillonite, illite) was very low (0 < Kd < 0.6 L kg−1), suggesting that mineral phases do not contribute significantly to CL‐20 sorption. Degradation of CL‐20 in sterile soils having different pH values increased as follows: sandy agricultural topsoil from Varennes, QC, Canada (VT) (pH = 5.6; Kd = 15 L kg−1; 8% loss) < clay soil from St. Sulpice, QC, Canada (CSS) (pH = 8.1; Kd = 1 L kg−1; 82% loss) < sandy soil provided by Agriculture Canada (SAC) (pH = 8.1, Kd = approximately 0 L kg−1; 100% loss). The faster degradation in SAC soil compared with CSS soil was attributed to the absence of sorption in the former. In summary, CL‐20 is highly immobilized by soils rich in organic matter. Although sorption retards abiotic degradation, CL‐20 still decomposes in soils where pH is >7.5, suggesting that it will not persist in even slightly alkaline soils.
Colloidal Phosphorus in Surface Runoff and Water Extracts from Semiarid Soils of the Western United States
Authors: Turner Benjamin L. , Kay Mary A. , Westermann Dale T. 
Published: June 2010

ABSTRACTColloidal particles in runoff may have an important role in P transfer from soils to waterbodies, but remain poorly understood. We investigated colloidal molybdate‐reactive phosphorus (MRP) in surface runoff and water extracts of calcareous arable soils from the semiarid western United States. Colloidal MRP was determined by ultrafiltration and operationally defined as MRP associated with particles between 1 μm and 1 nm diameter, although a smaller pore‐size filter (0.3 nm) was used to define the lower size limit of colloids in water extracts. In surface runoff from three calcareous soils generated by simulated sprinkler irrigation, colloidal MRP concentrations ranged between 0.16 and 3.07 μM, constituting between 11 and 56% of the MRP in the <1‐μm fraction. Concentrations were strongly correlated with agronomic and environmental soil‐test P concentrations for individual soils. Water extracts of a range of similar soils contained two size fractions of colloidal MRP: a larger fraction (1.0–0.2 μm) probably associated with fine clays, and a smaller fraction (3–0.3 nm) probably associated with Ca–phosphate minerals. Colloidal MRP was solubilized in the acidic medium of the colorimetric detection procedure, suggesting that a fraction of the filterable MRP in runoff from calcareous soils may not be as readily bioavailable as free phosphate in waterbodies. Our results suggest that colloidal MRP is an important but poorly understood component of P transfer in runoff from calcareous western U.S. soils and should be given greater consideration in mechanistic studies of the P transfer process.
Assessing Ground Water Vulnerability with the Type Transfer Function Model in the San Joaquin Valley, California
Authors: Stewart Iris T. , Loague Keith 
Published: June 2010

ABSTRACTThe recently developed type transfer function (TTF) simulation approach was applied to generate a regional‐scale nonpoint‐source ground water vulnerability assessment for the San Joaquin Valley, California. The computationally comparatively inexpensive TTF approach produces quantitative estimates of contaminant concentrations for large regional scales through characteristic functions based on different soil textures and their leaching properties. The TTF simulations employed an extensive soil and recharge database to estimate atrazine (1‐chloro‐3‐ethylamino‐5‐isopropylamino‐2,4,6‐triazine) concentrations at a compliance depth of 3 m resulting from a surface application. Two different sets of TTFs with two different levels of upscaling were used for spatially uniform and distributed recharge estimates. Results show that estimated atrazine concentrations can be related to soil survey information. Areas with high potential vulnerability to atrazine leaching were found for soils with low organic carbon content and sandy loam and loam textures. Travel times for atrazine peak concentrations to the compliance depth ranged from 350 to 730 d. The extent of areas with estimated atrazine concentrations above the maximum contaminant level was less extensive when uniform annual recharge values were used. Simulated TTF concentrations were highest for eastern Fresno County, a vulnerability pattern that is also supported by field observations. The TTF modeling approach is shown to be a useful tool for quantitative pesticide leaching estimates at regional scales significantly larger than those of previous studies.
Phosphorus Runoff from Incorporated and Surface‐Applied Liquid Swine Manure and Phosphorus Fertilizer
Authors: Daverede I. C. , Kravchenko A. N. , Hoeft R. G. , Nafziger E. D. , Bullock D. G. , Warren J. J. , Gonzini L. C. 
Published: June 2010

ABSTRACTExcessive fertilization with organic and/or inorganic P amendments to cropland increases the potential risk of P loss to surface waters. The objective of this study was to evaluate the effects of soil test P level, source, and application method of P amendments on P in runoff following soybean [Glycine max (L.) Merr.]. The treatments consisted of two rates of swine (Sus scrofa domestica) liquid manure surface‐applied and injected, 54 kg P ha−1 triple superphosphate (TSP) surface‐applied and incorporated, and a control with and without chisel‐plowing. Rainfall simulations were conducted one month (1MO) and six months (6MO) after P amendment application for 2 yr. Soil injection of swine manure compared with surface application resulted in runoff P concentration decreases of 93, 82, and 94%, and P load decreases of 99, 94, and 99% for dissolved reactive phosphorus (DRP), total phosphorus (TP), and algal‐available phosphorus (AAP), respectively. Incorporation of TSP also reduced P concentration in runoff significantly. Runoff P concentration and load from incorporated amendments did not differ from the control. Factors most strongly related to P in runoff from the incorporated treatments included Bray P1 soil extraction value for DRP concentration, and Bray P1 and sediment content in runoff for AAP and TP concentration and load. Injecting manure and chisel‐plowing inorganic fertilizer reduced runoff P losses, decreased runoff volumes, and increased the time to runoff, thus minimizing the potential risk of surface water contamination. After incorporating the P amendments, controlling erosion is the main target to minimize TP losses from agricultural soils.
Biological Effects of Wood Ash Application to Forest and Aquatic Ecosystems
Authors: Aronsson K. Andreas , Ekelund Nils G. A. 
Published: June 2010

ABSTRACTThe present review aims to summarize current knowledge in the topic of wood ash application to boreal forest and aquatic ecosystems, and the different effects derived from these actions. Much research has been conducted regarding the effects of wood ash application on forest growth. Present studies show that, generally speaking, forest growth can be increased on wood ash–ameliorated peatland rich in nitrogen. On mineral soils, however, no change or even decreased growth have been reported. The effects on ground vegetation are not very clear, as well as the effects on fungi, soil microbes, and soil‐decomposing animals. The discrepancies between different studies are for the most part explained by abiotic factors such as variation in fertility among sites, different degrees of stabilization, and wood ash dosage used, and different time scales among different studies. The lack of knowledge in the field of aquatic ecosystems and their response to ash application is an important issue for future research. The few studies conducted have mainly considered changes in water chemistry. The biotoxic effects of ash application can roughly be divided into two categories: primary and secondary. Among the primary effects is toxicity deriving from compounds in the wood ash and cadmium is probably the worst among these. The secondary effects of wood ash are generally due to its alkaline capacity and a release of ions into the soil and soil water, and finally, watercourses and lakes. Given current knowledge, we would recommend site‐ and wood ash–specific application practices, rather than broad and general guidelines for wood ash application to forests.
Environmental Concentrations of Agricultural Herbicides in Saskatchewan, Canada: Bromoxynil, Dicamba, Diclofop, MCPA, and Trifluralin
Authors: Waite D. T. , Cessna A. J. , Grover R. , Kerr L. A. , Snihura A. D. 
Published: June 2010

ABSTRACTHerbicides are the most commonly used group of agricultural pesticides on the Canadian Prairies and, in 1990, more than 20000 Mg of herbicides were applied in the provinces of Alberta, Saskatchewan, and Manitoba. The present paper reports on environmental concentrations of five herbicides currently used in the prairie region. The herbicides bromoxynil [3,5‐dibromo‐4‐hydroxy‐benzonitrile], dicamba [3,6‐dichloro‐o‐anisic acid], diclofop [(RS)‐2‐[4‐(2,4‐dichlorophenoxy)‐phenoxy]propanoic acid], MCPA [(4‐chloro‐2‐methylphenoxy)acetic acid], and trifluralin [α,α,α‐trifluoro‐2,6‐dinitro‐N,N‐isopropyl‐p‐toluidine] were measured in the atmosphere, bulk atmospheric deposits, surface film, and dugout (pond) water at two sites near Regina, Saskatchewan, during 1989 and 1990. All five herbicides were detected in air and surface film and all but trifluralin were detected in the bulk atmospheric deposits and dugout water. Trifluralin was most frequently detected in air (79% of samples) whereas bromoxynil was present in maximum concentration (4.2 ng m−3). MCPA was present in maximum levels in bulk atmospheric (wet plus dry) deposits (2350 ng m−2 d−1), surface film (390 ng m−2), and dugout water (330 ng L−1), whereas dicamba was most frequently detected in surface film (47%) and dugout water (97%). The highest quantities of the herbicides tended to be present during or immediately after the time of regional application.
Accumulation of Perchlorate in Aquatic and Terrestrial Plants at a Field Scale
Authors: Tan Kui , Anderson Todd A. , Jones Matthew W. , Smith Philip N. , Jackson W. Andrew 
Published: June 2010

ABSTRACTPrevious laboratory‐scale studies have documented perchlorate ClO−4 uptake by different plant species, but less information is available at field scale, where ClO−4 uptake may be affected by environmental conditions, such as distance to streams or shallow water tables, exposure duration, and species. This study examined uptake of ClO−4 in smartweed (Polygonum spp.) and watercress (Nasturtium spp.) as well as more than forty trees, including ash (Fraxinus greggii A. Gray), chinaberry (Melia azedarach L.), elm (Ulmus parvifolia Jacq.), willow (Salix nigra Marshall), mulberry [Broussonetia papyrifera (L.) Vent.], and hackberry (Celtis laevigata Willd.) from multiple streams surrounding a perchlorate‐contaminated site. Results indicate a large potential for ClO−4 accumulation in aquatic and terrestrial plants, with ClO−4 concentration in plant tissues approximately 100 times higher than that in bulk water. Perchlorate accumulation in leaves of terrestrial plants was also dependent on species, with hackberry, willow, and elm having a strong potential to accumulate ClO−4 Generally, trees located closer to the stream had a higher ClO−4 accumulation than trees located farther away from the stream. Seasonal leaf sampling of terrestrial plants indicated that ClO−4 accumulation also was affected by exposure duration, with highest accumulation observed in the late growing cycle, although leaf concentrations for a given tree were highly variable. Perchlorate may be re‐released into the environment via leaching and rainfall as indicated by lower perchlorate concentrations in collected leaf litter. Information obtained from this study will be helpful to understand the fate of ClO−4 in macrophytes and natural systems.
Regional Analysis of Climate, Primary Production, and Livestock Density in Inner Mongolia
Authors: Yu Mei , Ellis James E. , Epstein Howard E. 
Published: June 2010

ABSTRACTOverstocking is believed to be one of the principal causes for grassland degradation in northern China. For this reason, quantification of overstocking and spatiotemporal analysis are needed for this area. In this study, the relationship between annual rainfall and grassland aboveground net primary production (ANPP) was analyzed using data from 1982 to 1991 in the Inner Mongolia Autonomous Region (IMAR), China. Subsequently, rainfall‐based livestock carrying capacity was estimated and combined with livestock density calculated from county‐level livestock data from 1982 to 1991 to determine spatial and temporal patterns of a stocking rate index and its relationship with climatic factors. The results indicate the following. First, there was a significant linear relationship between annual rainfall and ANPP in IMAR and the slope of ANPP versus rainfall was greater than those found in South America and Africa, indicating higher rain‐use efficiency. Second, temporally averaged livestock density showed overstocking in most of the rural counties except for those in the cold north, where human populations are low and transportation systems are poor. Third, the stocking rate index increased with temperature, from less than 1.0 in the north, to greater than 2.0 in most of the southern IMAR. Within the central IMAR, the index increased from west to east, along the gradient of increasing rainfall. Fourth, long‐term dynamics of livestock density depicted continuous overstocking, more than 20%, from 1982 to 1991 along the western part of the NorthEast China Transect (NECT) within IMAR. Spatial planning of livestock densities according to carrying capacities and improved pastoral management are needed in this area.
Environmental Fate of Triasulfuron in Soils Amended with Municipal Waste Compost
Authors: Said‐Pullicino Daniel , Gigliotti Giovanni , Vella Alfred J. 
Published: June 2010

ABSTRACTThe amendment of soil with compost may significantly influence the mobility and persistence of pesticides and thus affect their environmental fate. Factors like adsorption, kinetics, and rate of degradation of pesticides could be altered in amended soils. The aim of this study was to determine the effects of the addition of compost made from source‐separated municipal waste and green waste, on the fate of triasulfuron [(2‐(2‐chloroethoxy)‐N‐[[4‐methoxy‐6‐methyl‐1,3,5‐triazin‐2‐yl)amino]carbonyl]benzenesulfonamide], a sulfonylurea herbicide used in postemergence treatment of cereals. Two native soils with low organic matter content were used. A series of analyses was performed to evaluate the adsorption and degradation of the herbicide in soil and in solution after the addition of compost and compost‐extracted organic fractions, namely humic acids (HA), fulvic acids (FA), and hydrophobic dissolved organic matter (HoDOM). Results have shown that the adsorption of triasulfuron to soil increases in the presence of compost, and that the HA and HoDOM fractions are mainly responsible for this increase. Hydrophobic dissolved organic matter applied to the soils underwent sorption reactions with the soils, and in the sorbed state, served to increase the adsorption capacity of the soil for triasulfuron. The rate of hydrolysis of triasulfuron in solution was significantly higher at acidic pH and the presence of organic matter fractions extracted from compost also slightly increased the rate of hydrolysis. The rate of degradation in amended and nonamended soils is explained by a two‐stage degradation kinetics. During the initial phase, although triasulfuron degradation was rapid with a half‐life of approximately 30 d, the presence of compost and HoDOM was found to slightly reduce the rate of degradation with respect to that in nonamended soil.
Distribution of Polychlorinated Biphenyls and Chlorinated Pesticide Residues in Trout in the Sierra Nevada
Authors: Ohyama Kazutoshi , Angermann Jeff , Dunlap Debra Y. , Matsumura Fumio 
Published: June 2010

ABSTRACTOrganochlorine compounds are known to be atmospherically transported to long distances from their original sources. To understand the influence of California's Sierra Nevada range on the air transport and subsequent distribution pattern of some of these residues within the range, we have chosen salmonid fish as an indicator species. Fish were collected from 10 locations throughout the northern and central Sierra Nevada and polychlorinated biphenyl (PCB), toxaphene, chlordane, and DDT [1,1,1‐trichloro, 2,2′‐bis (p‐chlorophenyl) ethane] residues in muscle tissue were analyzed. Rainbow trout (Oncorhynchus mykiss) were found in all sampling locations, and therefore analyses mainly focused on this species. When similar‐sized rainbow trout samples from several similar oligotrophic, high‐altitude lakes and streams were compared, it became apparent that altitude is one of the factors affecting the residual levels of PCB (r2 = 0.882), but not for total DDT, toxaphene, or chlordane in trout. Analysis of correlations among these four organochlorine compound residue groups indicated that there are modest correlations in patterns of distribution between chlordane vs. toxaphene (r2 = 0.345), and chlordane vs. total DDT (r2 = 0.239), but toxaphene residues are not correlated with PCB or total DDT. In view of significant correlation to the altitude it is concluded that PCB residue in rainbow trout is a good monitoring tool for studying the effect of high‐altitude mountain ranges on the long‐range transport and distribution of those persistent pollutants.
Dissolution of Phosphate in a Phosphorus‐Enriched Ultisol as Affected by Microbial Reduction
Authors: Hutchison Kimberly J. , Hesterberg Dean 
Published: June 2010

ABSTRACTPhosphorus dissolution often increases as soils become more reduced, but the mechanisms are not fully understood. The objectives of this research were to determine rates and mechanisms of P dissolution during microbial reduction of a surface soil from the North Carolina Coastal Plain. Duplicate suspensions of silt + clay fractions from a Cape Fear sandy clay loam (fine, mixed, semiactive, thermic Typic Umbraquult) were reduced in a continuously stirred redox reactor for 40 d. We studied the effects of three treatments on P dissolution: (i) 2 g dextrose kg−1solids added as a microbial carbon source at time 0 d; (ii) 2 g dextrose kg−1solids split into three additions at 0, 12, and 26 d; and (iii) no added dextrose. After 40 d of reduction, concentrations of dissolved reactive phosphorus (DRP) were similar for all treatments and increased up to sevenfold from 1.5 to 10 mg L−1The initial rate of reduction and dissolution of DRP was significantly greater for the 0‐d treatment. A linear relationship (R2= 0.79) was found between DRP and dissolved organic carbon (DOC). Dissolved Fe and Al and pH increased, suggesting the formation of aqueous Fe– and Al–organic matter complexes. Separate batch experiments were performed to study the effects of increasing pH and citrate additions on PO4dissolution under aerobic conditions. Increasing additions of citrate increased concentrations of DRP, Fe, and Al, while increasing pH had no effect. Results indicated that increased dissolved organic matter (DOM) during soil reduction contributed to the increase in DRP, perhaps by competitive adsorption or formation of aqueous ternary DOM–Fe–PO4or DOM–Al–PO4complexes.
Nitrogen Fertilizer Form and Associated Nitrate Leaching from Cool‐Season Lawn Turf
Authors: Guillard Karl , Kopp Kelly L. 
Published: June 2010

ABSTRACTVarious N fertilizer sources are available for lawn turf. Few field studies, however, have determined the losses of nitrate (NO3–N) from lawns receiving different formulations of N fertilizers. The objectives of this study were to determine the differences in NO3–N leaching losses among various N fertilizer sources and to ascertain when losses were most likely to occur. The field experiment was set out in a completely random design on a turf typical of the lawns in southern New England. Treatments consisted of four fertilizer sources with fast‐ and slow‐release N formulations: (i) ammonium nitrate (AN), (ii) polymer‐coated sulfur‐coated urea (PCSCU), (iii) organic product, and (iv) a nonfertilized control. The experiment was conducted across three years and fertilized to supply a total of 147 kg N ha−1 yr−1 Percolate was collected with zero‐tension lysimeters. Flow‐weighted NO3–N concentrations were 4.6, 0.57, 0.31, and 0.18 mg L−1 for AN, PCSCU, organic, and the control, respectively. After correcting for control losses, average annual NO3–N leaching losses as a percentage of N applied were 16.8% for AN, 1.7% for PCSCU, and 0.6% for organic. Results indicate that NO3–N leaching losses from lawn turf in southern New England occur primarily during the late fall through the early spring. To reduce the threat of NO3–N leaching losses, lawn turf fertilizers should be formulated with a larger percentage of slow‐release N than soluble N.
Dynamic Respiration Index as a Descriptor of the Biological Stability of Organic Wastes
Authors: Adani Fabrizio , Confalonieri Roberto , Tambone Fulvia 
Published: June 2010

ABSTRACTAnalytical methods applicable to different organic wastes are needed to establish the extent to which readily biodegradable organic matter has decomposed (i.e., biological stability). The objective of this study was to test a new respirometric method for biological stability determination of organic wastes. Dynamic respiration index (DRI) measurements were performed on 16 organic wastes of different origin, composition, and biological stability degree to validate the test method and result expression, and to propose biological stability limits. In addition, theoretical DRI trends were obtained by using a mathematical model. Each test lasted 96 h in a 148‐L‐capacity respirometer apparatus, and DRI was monitored every hour. The biological stability was expressed as both single and cumulative DRI values. Results obtained indicated that DRI described biological stability in relation to waste typology and age well, revealing lower‐stability waste characterized by a well‐pronounced DRI profile (a marked peak was evident) that became practically flat for samples with higher biological stability. Fitting indices showed good model prediction compared with the experimental data, indicating that the method was able to reproduce the aerobic process, providing a reliable indication of the biological stability. The DRI can therefore be proposed as a useful method to measure the biological stability of organic wastes, and DRI values, calculated as a mean of 24 h of the highest microbial activity, of 1000 and 500 mg O2 kg−1 volatile solids (VS) h−1 are proposed to indicate medium (e.g., fresh compost) and high (e.g., mature compost) biological stabilities, respectively.