Anaerobic nitrogen-fixing bacteria in U.S.S.R. soils

An account is given of a study of the size and diversity of populations of Clostridium pasteurianum and C. acetobutylicum in representative soils sampled at various latitudes and altitudes within the U.S.S.R. Evidence is presented to show that the two species are well adapted to soil and climatic factors in terms of the relative dominance of the two species and in terms of differences in their growth-temperature characteristics, carbohydrate utilization and fermentation products, nitrogen fixation and the comparative chemistry of their cells. In all of these characteristics, C. pasteurianum was more variable than C. acetobutylicum.     

Molecular tritium uptake in Southeastern U.S. soils

Molecular tritium deposition occurred in all soils tested. Deposition velocities for tritium ranged from 0.0025 to 0.11cm s^?1 with a geometric mean of 0.028 cm s^?1. Coring surveys from six different sites showed that deposition rates were highest in the upper 20 cm of soil, with little activity evident below this depth. Plant cover did not appear to have a strong direct influence on the profile of tritium deposition activity.     

Pedogenesis and surface charge of some Andic soils in Washington,U.S.A.

Chemical and surface charge characteristics were determined for three soils that were formed in a mantle of volcanic tephra along a bio-climatic gradient in forest in northcentral Washington state. The soils are Nevine silt loam (Typic Vitrandept), Manley silt loam (Entic Cryandept), and Moses silt loam (Andic Cryochrept). Selective dissolution analyses for Al, Fe, and Si suggests that the weathering products in the ash mantle are poorly crystalline aluminosilicates, hydrous and crystalline Fe-oxides, and Al-humus complexes in decreasing order of abundance. The chemical and physical data indicate that Moses silt loam has undergone a greater degree of weathering than either Nevine silt loam or Manley silt loam, and we attribute this to differences in the weathering environment. The measured points of zero charge parameters are typical for soils that are dominated by amphoteric surfaces: the soils exhibit charge reversal, and charge magnitude is dependent upon pH and electrolyte concentration. The point of zero salt effect ranged from 5.1 to 5.3, and the point of zero net charge ranged from 4.3 in Nevine silt loam to 5.4 in Moses silt loam. Pedogenesis has not caused large enough differentiation among the soils to allow us to use zero charge parameters as indicators of the degree of pedogenesis.     

Baseline element concentrations in soils and plants,Bull Island,Cape Romain National Wildlife Refuge,South Carolina,U.S.A.

Baseline element concentrations are given for Spanish moss (Tillandsia usneoides), loblolly pine (Pinus taeda), and associated soils. Baseline and variability data for ash, Al, Ba, C, Ca, Cd, Ce, Co, Cr, Cu, Fe, K, La, Li, Mg, Mn, Na, Nb, Nd, Ni, P, Pb, S, Sc, Sr, Th, Ti, V, Y, and Zn are reported; however, not all variables are reported for all media because, in some media, certain elements were below the analytical detection limit. Spatial variation in element concentration among and within 0.5 km grid cells are given for each of the media. In general, only a few elements in Spanish moss showed statistically significant landscape patterns, whereas several elements in loblolly pine and in soils exhibited differences among sampling grids. Significant differences in the concentration of three elements in Spanish moss and eight elements (including total S) in loblolly pine were observed between two sampling dates (November and June); however, the absolute amount of these differences was small. Except for perhaps Ni and Pb concentrations in Spanish moss, element levels in all sample media exhibited ranges that indicate natural rather than anthropogenic additions of trace elements.     

Human-altered and human-transported (HAHT) soils in the U.S. soil classification system

ABSTRACT

Human-altered and human-transported (HAHT) soils are widespread across the globe and are concentrated near where people live and work. Although some of the HAHT soils are significant because they can be hazardous to human, animal, and plant health, most are not mapped or classified to the same extent as agricultural soils. The purpose of this article is to discuss the occurrence, types, and importance of HAHT soils and to document the historical and proposed classification of HAHT soils in Soil Taxonomy. There are two main forms of materials that define HAHT soils: human-altered soils formed in human-altered materials (HAM) from the soil surface to 50 cm (or to bedrock if shallower) or more and human-transported soils formed in human-transported materials (HTM) from the soil surface to 50 cm (or to bedrock if shallower) or more. The HAHT soils mainly occur in urban areas, transportation corridors, mined lands, landfills, filled shallow water, and agricultural areas on anthropogenic landforms. Hazards include danger from radioactivity, pollution, content of hazardous artifacts, or presence on unstable landforms that may fail during heavy rains or earthquakes. The HAHT soils are extensive, and their extent is growing. In the past, few HAHT soils were described or classified adequately because the U.S. Soil Taxonomy system was established for agricultural and other naturally occurring soils. However, HAHT soils are now being recognized and classified in many soil classification systems at very high levels. A new soil order is proposed for U.S. Soil Taxonomy that would include the most obvious profoundly and intentionally altered HAHT soils. A discussion and justification is given for an unofficial proposal. Input will be collected from international groups of scientists, and modifications of the unofficial proposal are expected. The long-term result of establishing a new soil order will be to enable proper classification, allocation, and mapping of HAHT soils worldwide.     

Relations between stratigraphy,geomorphology and soils in Coastal Plain areas of Southeastern U.S.A.

Small infiltrometers were used to measure infiltration rates into strongly and maderately developed compound prisms, sampled individually from surface layers of two dry clay soils. Initially, both rates were equally high but after three hours a higher rate was measured for the moderately developed compound prisms. These data were used to interpret adsorption and outflow phenomena of water in undisturbed, large and initially dry soil cores (diameter 20 cm) sampled from the upper 20 cm of the two soils, following application rates of about 8 mm/h and 28 mm/h. The two soils adsorbed an average of 6.4 mm water before the start of discharge, independent of the applied intensity. They discharged water at a constant and high rate for several hours, allowing adsorption of about 10% of the applied water. This represents a high degree of “short-circuiting” for all treatments, except one: adsorption was 40% at the 28 mm/h rate for the soil with the moderately developed prisms. The moisture content in the transmission zone was not constant as it would have been in homogeneous soil but increased regularly as a function of time. Slow wetting of both soils through a crust, followed by rain with an intensity of 30 mm/h, resulted in the adsorption of only about 3% of the applied rain in both soils.In general, more effective wetting of a dry clay surface soil at a given rainfall intensity is initially associated with less “short-circuiting” to deeper horizons. However, the resulting higher moisture content allows less adsorption in the surface layer and is therefore associated with increased “short-circuiting” thereafter, as long as large vertical pores have not been closed by swelling.     

Land use and management of soils with relict duripans,southwestern oregon (U.S.A.)

Paleosolic features are important to land use and management of soils on fan terraces in southwestern Oregon. Soil-geomorphology studies identified relict duripans and established the distribution of associated Durochrepts, Duraquolls and Argixerolls. These soils represent two late Pleistocene geomorphic surfaces, each with distinct kinds of periglacial patterned ground. Soil behavior is discussed in terms of soil characteristics and qualities and compared for cropland, grazing, construction, and waste disposal.     

The origin and early genesis of clay bands in youthful sandy soils along lake Michigan,U.S.A.

A beach ridge and dune complex with good radiocarbon control sampling the last 3500 radiocarbon years B.P. provides new insights on the early genesis of clay bands in sandy soils. Soil profiles were sampled by age groups, described in the field, and then subjected to laboratory analyses for particle-size distribution, pH, organic carbon, carbonate minerals, and extractable iron and manganese. This study suggests that small increases in pH, brought about by small increases in carbonate content within the soil profile, are responsible for flocculating small amounts of illuviated clay. This process, along with a transition to a greater hydraulic conductivity with soil depth due to coarser textures in any given profile, partly explains the existence and possible reason for the initiation of illuvial zones and eventually for clay-band horizons. A pronounced increase in the thickness of incipient clay-band horizons in soils older than 2300 years appears due to finer textures in the parent materials than are present in younger soils. Because of slightly reduced porosity and lower permeability, carbonates and a high pH are retained in both illuvial and eluvial horizons of some of these older soils. In addition, only in those profiles older than 2300 years do clay and iron oxide concentrations coincide and is there some suggestion of greater amounts of extractable manganese in horizons of minimum iron and clay. A pronounced segregation of clay-iron bands is not apparent at the study area but should occur in future years as additional amounts of iron and clay are deposited.     

Aerobic and microaerophilic actinomycetes of typical agropeat and peat soils

A high number (from tens of thousands to millions of CFU/g of soil) of actinomycetes and a high diversity of genera were found in typical peat and agropeat soils. Agricultural use increases the number and diversity of the actinomycete complexes of the peat soils. In the peat soils, the actinomycete complex is represented by eight genera: Streptomyces, Micromonospora, Streptosporangium, Actinomadura, Microbispora, Saccharopolyspora, Saccharomonospora, and Microtetraspora. A considerable share of sporangial forms in the actinomycete complex of the peat soils not characteristic of the zonal soils was revealed. The number of actinomycetes that develop under aerobic conditions is smaller by 10–100 times than that of aerobic forms in the peat soils. Among the soil actinomycetes of the genera Streptomyces, Micromonospora, Streptosporangium, Actinomadura, Microbispora, and Microtetraspora, the microaerophilic forms were found; among the Saccharopolyspora and Saccharomonospora, no microaerophilic representatives were revealed.     

Trace elements in surface soils from the mineralized area of Madison County, Missouri, U.S.A.

Duplicate, bulked surface soil samples, from sites 10m apart, were collected at 97 locations 1000 m apart on a regular grid measuring 8x11 km. Data were obtained for Ag, Ba, Be, Cd, Co, Cr, Cu, Li, Mn, Ni, Pb, V and Zn. One field sample was a good predictor of its nearby duplicate for Co, Cu, Ni and Pb, satisfactory for Ba, Be, Cr, Mn and Zn, but poorer for Cr, Li and V. Maps of the variation in precision of the field samples did not reveal any association between abandoned mine sites and high variability. The median coefficient of variation for trace elements in the field duplicates was between 8 and 19.5%. The duplicated field data were averaged to yield a mean soil metal concentration at each sample location. Concentrations of Ba, Be, Cr, Li, Sr and V were comparable with other published values for similar soils in Missouri. Concentrations of Co, Cu, Mn, Ni, Pb and Zn were higher which was explained by pollution from mining activities. A graphical technique was used to calculate background levels for metals in the second group. Samples of forest litter were collected at 12 locations: Ag, Ba, Cd, Mn, Sr and Zn concentrations were higher in the litter whereas Li and V concentrations were higher in the subjacent mineral soil. Computer isoline maps of the distribution of elements revealed an association between areas of high soil Cu, Co, Ni, Pb and Zn and abandoned mines or mineralized rocks.     

Terrestrial field dissipation of diclosulam at four sites in the United States.

The soil dissipation of diclosulam was studied using 14C-labeled and nonradiolabeled material in Mississippi, North Carolina, Georgia, and Illinois between 1994 and 1997. The test substance was preemergence broadcast applied at target rates of 35 and 37 g ai x ha(-1) for the 14C-labeled and the nonradiolabeled studies, respectively. The degradation of diclosulam was rapid with half-lives ranging from 13 to 43 days at the four sites. Rapid degradation rates and the increasing sorption to soil over time resulted in low persistence and mobility of this compound. Metabolite formation and dissipation in the field reflected observations of photolysis, hydrolysis, and aerobic soil metabolism studies in the laboratory. The rapid field dissipation rates, metabolite formation patterns, and sorption characteristics obtained in these field studies were consistent with the laboratory data generated for diclosulam, and reflect the multiple concurrent degradation mechanisms occurring in the field.     

Characterization and Degradation of Petroleum Hydrocarbons Following an Oil Spill into a Coastal Environment of South Texas, U.S.A.

Petroleum hydrocarbons were characterized at eleven sites withinthe sediments of a coastal stream in south Texas, U.S.A. following a medium sized crude oil spill. Bank and open-water(deep) sediments were collected at each site. Hydrocarbonstargeted for analysis included 22 aliphatic hydrocarbons (C-11to C-34) and 16 polynuclear aromatic hydrocarbons. Sedimentconcentrations were measured at intervals of 1, 2, 3, 4, 6, and12 months post-spill. Higher hydrocarbon concentrations were observed for a longerduration within the deep sediments than bank sediments. Initialhydrocarbon constituents in impacted sediments matched the crudeoil fingerprint accurately with the exception of the lighter-endhydrocarbons. The lighter-end aliphatic hydrocarbons areaffected immediately by evaporation and dissolution processesduring the spill event and were found below the detection levelsat most of the sites. Total hydrocarbon concentrations insediments within each hydrocarbon group returned to backgroundlevels by the end of the study period. Observed decreases inhigh molecular weight polycyclic aromatic hydrocarbons (PAH)concentrations exceeded known environmental degradation rateswhich suggests the influence of a sediment transport process. Overall, the fate of petroleum hydrocarbons within this type ofenvironment were likely related to both degradation and sedimenttransport processes. By the end of the study period, most individual PAH constituent concentrations were below thresholdconcentrations thought to produce toxic effects in marine andestuarine organisms. PAH constituents concentrations remainingabove threshold concentrations included benz(a)anthracene,chrysene, and benzo(a)pyrene.     

Survey of U.S. wheat for ochratoxin and aflatoxin.

A total of 291 hard red winter wheat samples, 286 hard red spring wheat samples, and 271 soft red winter wheat samples were analyzed for the presecne of ochratoxin and aflatoxin. Samples in all grades came from those collected during crop years 1970-1973 for grade determinations by the Agricultural Marketing Service, U.S. Department of Agriculture. Sensitivity limits of the analytical method as carried out were 1-3 ppb aflatoxin B1 and 15-30 ppb ochratoxin A. No aflatoxin was detected in any sample. Three samples of hard red winter wheat (Grades U.S. No. 4 and 5 and Sample Grade) contained ochratoxin A (trace, 35, and 25 ppb, respectively). Eight of the hard red spring wheats contained ochratoxin A (15-115 PPB); these were in Grades U.S. No. 4 and 5 and Sample Grade.     

Scientific principles for water utilization in the U.S.S.R.

Water resources are essential for economic and cultural development of a territory. Both economic development and the health of the people depend on the provision of pure water. Scientifically founded plans of water resources use and conservation should be based on a balance approach to the assessment of available water supply sources and, on the forecast of their interconnected change in the future in a close association with the forecast of the whole economy and culture of the studied region. In the future the main threat to the normal development of the economy and life will not be water deficiency but the conversion of rivers, lakes and other water supply sources into sewers. Therefore it is proposed that there be a complete cessation of sewage discharge (even of the so-called purified) into water supply sources while drawing up long-term water management balances.     

Sediment remediation: U.S. focus on capping and monitored natural recovery

The Battelle Conferences series represent the state-of-the-art of emerging technologies, science and management issues for contaminated sediment remediation. In the 2007 Conference held in Savannah, GA, two in situ technologies for cleanup sites were at the centre of interest: Sediment capping, a form of in situ containment, which involves the placement of a subaqueous covering of clean sediment and/or other materials to isolate contaminated sediments, and monitored natural recovery (MNR), where natural processes are used to mitigate the transfer of particle-bound contaminants into the water phase and/or biota. A third priority technology in the Superfund program, recommended by the U.S. Environmental Protection Agency (EPA), is environmental dredging, i.e., removing the sediments from the aquatic environment. About 30 platform or poster presentations dealt with in situ capping as a technology, reflecting the rapid developments in this field, both in assessments and enhancements of ‘classic’ passive caps and the development and demonstration of active capping technologies. Issues relevant to monitored natural recovery were spread throughout many sessions; e.g., contaminant source identification, control, remediation strategies; innovative characterization and assessment, chemical/toxicological/biological measurements and characterization, bioavailability of contaminants, contaminant fate and transport and remediation effectiveness: defining, monitoring, and demonstrating success. Presentations addressing the role of science and stakeholder input were complemented by discussions on the importance of data quality considerations, uncertainty analysis, and careful selection of reference sites highlighted the complex nature of these multidisciplinary assessments. Case studies, in which site-specific information was linked to regional management objectives, various approaches to watershed-scale assessment and management, and the role of ecosystem considerations, were all discussed in these sessions, as well as in a complementary panel discussion. One compelling feature of the Savannah Conference 2007 (relative to the first couple of meetings) is that there were a much larger number of presentations that provided the tools, models, case studies, etc to fill in the lines of evidence that allow a fair comparison between removal and in situ management when appropriate, and evidence of a growing acceptance that the residuals and impacts of removal approaches can at times offset perceived benefits, so that in situ management can be considered if exposure risk can be properly assessed.     

Forest management and biomass in the U.S.A.

There are a variety of opportunities to change land and forest management and, at the same time, create a positive impact on the current use of fossil energy. To the extent that these opportunities can be captured, they address the root cause of greenhouse warming-fossil fuel emissions-while, at the same time, improving economic opportunities, ecosystem productivity, and environmental conditions over broad areas. The need for better markets to absorb biomass energy, plus research to make biomass conversion more efficient, is probably the most important deterrent to achieving these possibilities.     

Root activity and carbon metabolism in soils

Summary Two different soils were amended with ¹⁴C-labelled plant material and incubated under controlled laboratory conditions for 2 years. Half the samples were cropped with wheat (Triticum aestivum) 10 times in succession. At flowering, the wheat was harvested and the old roots removed from the soil, so that the soil was continuously occupied by predominantly active root systems. The remaining samples were maintained without plants under the same conditions. During the initial stages of high microbial activity, due to decomposition of the labile compounds, the size of the total microbial biomass was comparable for both treatments, and the metabolic quotient (qCO₂-C = mg CO₂-C·mg^–1 Biomass C·h^–1) was increased by the plants. During the subsequent low-activity decomposition stages, after the labile compounds had been progressively mineralized, the biomass was multiplied by a factor of 2–4 in the presence of plants compared to the bare soils. Nevertheless, qCO₂-C tended to reach similar low values with both treatments. The ¹⁴C-labelled biomass was reduced by the presence of roots and qCO₂-¹⁴C was increased. The significance of these results obtained from a model experiment is discussed in terms of (1) the variation in the substrate originating from the roots and controlled by the plant physiology, (2) nutrient availability for plants and microorganisms, (3) soil biotic capacities and (4) increased microbial turnover rates induced by the roots.     

Mercury in soils and crops from fields receiving high cumulative sewage sludge applications: Validation of U. S. EPA's risk assessment for human ingestion

The Metropolitan Water Reclamation District of Greater Chicago (MWRDGC) has owned and operated a 6320 ha Dedicated Beneficial Sludge Utilization Site in Fulton County, Illinois since 1971. The site consists of calcareous strip mine spoil intermingled with placed land. Sewage sludge from Chicago is barged to the site, located approximately 185 miles southwest of the city, and utilized to reclaim the strip mined soils and to fertilize the corn and wheat crops grown on them. Fields have received as much as 1317 dry Mg ha^?1 of sewage sludge since 1971. Sludge Hg concentrations have ranged from 1.1 to 8.5 mg Hg kg^?1 with mean concentration of 3.31 mg Hg kg^?1, and maximum cumulative Hg loading rates are approximately 4 kg ha^?1. Sludge applications have significantly increased extractable soil Hg concentrations, and regression analysis indicates that from 80 to 100% of the Hg applied to soils in sewage sludge since 1971 still resides in the top 15 cm of soil. Since 1985 the MWRDGC has been monitoring Hg concentration in corn leaf and grain, wheat grain and soils at the Fulton County site. Monitoring data indicate that 98.8% of the corn grain samples, 93.0% of the wheat samples and 50.7% of the corn leaf samples collected from 1985 through 1992 had Hg concentrations below detectable limits (<25μg kg^?1). Cumulative Hg loading rates are utilized along with crop tissue concentrations to compute crop uptake response slopes (UC) for Hg into plant tissues at the Fulton County site. The UC for corn and wheat grain was zero and for corn leaf was ?0.0014 (mg Hg/kg tissue)/(kg Hg/ha soil), which indicate that sewage sludge additions did not increase plant tissue Hg concentrations at the Fulton County site. The negative UC obtained for corn leaf may actually indicate that sewage sludge applications decreased Hg uptake from mined soils possibly due to organic carbon and sulfides in the anaerobically digested sludge binding native Hg. The United States Environmental Protection Agency (U. S. EPA) has recently promulgated their 40 CFR Part 503 regulation for sewage sludge use and disposal. The rule sets risk based limits on ten metals, including Hg, in sludges that are land applied. Exposure pathways involving plant uptake of Hg are briefly discussed and it is shown that the UC used in U. S. EPA's risk assessment models for these pathways overpredict uptake of Hg by crops when compared with the UC derived from the MWRDGC's monitoring data at Fulton County.