Tons Of Soil Research Articles

Exposure Assessment of TSEs from the Landspreading of Meat and Bone Meal

Recent changes in European legislation have meant that certain processed abattoir waste, which has been appropriately heat treated and ground to a specified particle size, can be spread on nonpasture agricultural land. This has opened the way for the potential landspreading of mammalian meat and bone meal (mMBM) derived from animals slaughtered for human consumption. This article reports on two separate case studies (Study 1 carried out in Great Britain (GB) and Study 2 carried out in Ireland) on the potential exposure to TSE infectivity following the spreading of abattoir waste (derived from animals slaughtered for human consumption) on nonpasture agricultural land. For Study 1, the average TSE infectivity on nonpasture agricultural land per year from sheep with scrapie was found to be higher (five orders of magnitude) than that estimated for BSE in cattle (3.9 x 10(-3) Ovine Oral ID(50)/ton of soil compared to 3.3 x 10(-8) Bovine Oral ID(50)/ton of soil). The mean estimate for BSE in sheep was 8.1 x 10(-6) Ovine Oral ID(50)/ton of soil. The mean level of infectivity in mMBM was assessed to be 1.2 x 10(-5) and 2.36 x 10(-5) ID(50)/ton of mMBM for Study 1 and 2, respectively. For Study 2 the spreading of mMBM was estimated to result in infectivity on nonpasture land of 1.62 x 10(-8) Bovine Oral ID(50)/m(3). The mean simulated probability of infection per year per bovine animal was 1.11 x 10(-9). Given the low infectivity density and corresponding low risks to bovines the spreading of mMBM could be considered a viable alternative for the utilization of mMBM.

Development Of A Storm Runoff Simulator: Part 1 – Design Considerations

Evaluation of conservation buffers has relied primarily on small-scale plot (30 to 50 m2) studies with a limited range of buffer widths and field to buffer area ratios (BARs). Most studies used simulated runoff at steady flow rates. There is a need to evaluate conservation buffers installed at NRCS design widths and BARs to assess how well in-field buffers reduce nonpoint source pollution, especially for unsteady flow. The goal of this project is to develop a storm runoff simulator to distribute variable flow rates and contaminant concentrations across the upslope end of a buffer in a reproducible fashion. The simulator design should allow for easy transportation and adaptability to terrain and resource constraints found in the field. The SCS CN Method and the MUSLE were used to evaluate eight alternative combinations of BAR and buffer size. Buffer size ranged from 30 to 67.5 m2. Given the design constraints of less than 1 metric ton of soil per simulation, only a 1- 9-m plot size met the design criteria. Based on realistic constraints of a 7580-L available water supply, the final design constraints included a 7.3-L s-1 peak flow rate and 0.71 tons of soil, for a 1- 9-m plot, which allowed for BARs up to 49:1.

Development of a Storm Runoff Simulator: Part 2 – Water Output Control Device

Few studies have evaluated conservation buffers at field to buffer area ratios of 30:1 or greater. A storm runoff simulator is needed to better evaluate flow hydraulics, sediment trapping, and water quality benefits of field-scale conservation buffers. Based on an engineering analysis using MUSLE and the SCS Curve Number Method, it was determined that a simulator could be developed for a 1- 9-m buffer plot, with input constraints of 7580-L stored water and 0.71 metric tons of soil. The objective of this study was to design, build, and test a prototype runoff simulator water output control device operating under gravity flow conditions. The control device regulates flow using a gear motor mounted on a rotary gate valve, and a feedback control system between a flow meter and the rotary valve. A time-compressed 10-yr, 2-h SCS design hydrograph with a 7.3-L s-1 peak flow rate was used to calibrate the flow control device for optimal performance with large changes in flow rate, and for repeatability with a variety of hydrograph shapes. When reproducing the compressed SCS hydrograph, the control device maintained comparable efficiencies among repetitions; with a 2% error between root mean square error and the total flow range. Hydrographs with step changes in flow rate, flow rate plateaus, multiple peaks, and flow rates up to 9.8 L s-1 could be simulated with comparable efficiencies and 4% to 6% error.

Colony Productivity of the Fungus-Gardening Ant <I>Trachymyrmex septentrionalis</I> (Hymenoptera: Formicidae) in a Florida Pine Forest

The ecology of the fungus-gardening ant Trachymyrmex septentrionalis McCook (Hymenoptera: Formicidae) was investigated in a northern Florida longleaf pine, Pinus palustris Mill., forest. This ant is extremely abundant in pine sandhill in the Apalachicola National Forest, in north Florida; a hectare contains on average >1,000 nests, 235,000 T. septentrionalis workers, and 3.5 kg of fungus garden. When colony size and performance were estimated from excavations and the weight of sand in the tumulus, nests were larger and produced the most offspring in open, treeless habitats, whereas the smallest and least productive nests occurred in wooded areas. Our data suggest that the warm soils of open sites stimulate worker activity and colony growth, and cool soils of shaded, wooded sites depress performance. Moreover soils with extremely warm temperatures may have an inhibitory effect because the ants and fungus are susceptible to desiccation and excessive warmth, respectively. This suggests that T. septentrionalis is an indicator ant species of habitat quality in longleaf pine sandhills because its performance seems to be positively related to the natural disturbance regime—frequent fires occurring in the summer. Soil displacement is possibly a major effect that this ant has on the forest ecosystems: colonies may excavate over 1 metric ton of soil each year in a typical hectare of pine forest. The effect of this soil turnover is probably considerable in these nutrient-poor, sandy soils. Experiments are needed to determine the role of this highly abundant ant in longleaf pine forests.

Industrial Park Remediation in Aviles

Asturias has traditionally been a region with a primary industry based economy that, to a large extent, developed around mining and the iron and steel industry. Consequently, the areas where such production activities were implemented have been subject to a high contamination potential, accentuated by the fact that the factories were located on quaternary soils, very sensitive to pollution, on which anthropic fill materials from the local industries were dumped. Over the years, old factories have been dismantled, leaving a legacy of contaminated soils, many of which, when released by the original production activity, have been occupied by new companies, as is the case with a large number of the existing industrial parks. In some cases the growth of the cities leads to an increasing demand for building land, with the result that the lands have been used for residential purposes. This situation is further aggravated by the limited land availability in the region, owing to a large extent to its abrupt orography. The dismantling of the installations configuring the front‐end facilities of Empresa Nacional Siderúrgica de España (ENSIDESA) led to the segregation of 1,650,000 square metres in August 1997. This land was allo-cated to the creation of a new industrial park, as well as an auxiliary area to complement the Avilés port facilities. After analysing the contamination existing in the area, an assessment was made for determining the possible risks it entailed for the new intended use of the land. As a result, 22,000 tonnes of soil affected by dumping, spillage and leakage of hydrocarbons were removed, together with 2,500 tonnes of soil contaminated with polychlorobiphenyls (PCBs). In order to prevent the contamination from spreading, the material removed was classified and stored in an area close to the port, while awaiting the decision on the best treatment to be applied. The treatment finally selected was the process known as thermal desorption, to be carried out with mobile equipment that would operate in the area where the contaminated soils were stored. The treatment lasted from December 2002 to May 2003, mainly due to the fact that after regenerating the hydrocarbon‐polluted material, the treatment plant was modified to make it suitable for the recovery of the PCB contaminated soils. It was the first time such a process was applied in Spain. The target levels defined for contaminated soil remediation were achieved, and the soils thus regenerated were used as a basis for the foundations of various industrial units built in the park.

Considerations for targeting soil conservation investments in southern Honduras

Honduras is vulnerable to catastrophic losses associated with landslides and flooding in the aftermath of hurricanes (Fifi in 1974 and Mitch in 1998, most recently). Taking a watershed-scale approach to targeting conservation programs to promote stability on cropped steeplands in rural southern Honduras would reduce landslide and flooding risks, thus protecting export-earning downstream industries and investments. A case study of the Land Use and Productivity Enhancement project (1990–1998) was conducted to estimate the costs of extension programming to promote three conservation technologies – mulching, vetiver grass barriers, and rock walls – and to assess their efficacy (i.e., cost per ton of soil saved). Geographic Information System mapping tools were applied to suggest conservation priorities for steepland sites that are the most prone to landslides, both to maximize the soil saved per hectare protected and to minimize downstream damages.

TOLERÂNCIA DE PERDAS DE SOLO NA BACIA DO RIO ITIQUIRA, MATO GROSSO, BRASIL

TOLERÂNCIA DE PERDAS DE SOLO NA BACIA DO RIO ITIQUIRA, MATO GROSSO, BRASIL

In Situ flushing of contaminated soils from a refinery: Organic compounds and metal removals

AbstractThis article demonstrates the applicability of in situ flushing for the remediation of soil contaminated with petroleum hydrocarbons at a Mexican refinery. The initial average total petroleum hydrocarbon (TPH) concentration for the demonstration field test was 55,156 g/kg. After six weeks of in situ flushing with alternate periods of water and water/surfactant, an average concentration of 1,407 mg/kg was reached, achieving a total removal efficiency of 98 percent. At the end of the process, no hydrocarbons such as diesel; gasoline; benzene, toluene, ethyl benzene, and xylene (BTEX); or petroleum aromatic hydrocarbons (PAHs) were found. Iron washing achieved a removal efficiency of 70 percent, and for vanadium, the removal efficiency was 94.4 percent. The volume of soil treated was 41.6 m3 (38 m2), equivalent to 69.5 tons of soil. A rough calculation of the process costs estimated a total cost of $104.20/m3 ($114.00/m2). Our research indicates that there are a few studies demonstrating in situ flushing experiences under field conditions where both organic (TPH, diesel, gasoline, PAHs, BTEX) and metal (iron and vanadium) removals are reported. © 2004 Wiley Periodicals, Inc.

Digging and soil turnover by a mycophagous marsupial

The woylie Bettongia penicillata is a small (1 kg) kangaroo-like marsupial that digs to obtain the fruiting bodies of fungi. The number of woylies in a 60 ha area of sclerophyll woodland in south-western Australia was estimated using mark-recapture at 3 month intervals over 3 successive years. The number of new diggings by woylies, determined at the same intervals, allowed an assessment of the rate of digging per individual. This varied three-fold from 38 to 114 diggings per individual per night, with no consistent seasonality. On average, each woylie displaced 4.8 tonnes of soil annually.

Performance of Ornamental Plantsin Bioremediated Soil

At the conclusion of the Gulf War in 1991, more than 700 gushing wells discharged over 60 million barrels of crude oil, forming nearly 300 oil lakes that covered more than 49 km 2 of land surface. This contaminated approximately 40 million tons of soil. An additional 700 km 2 of terrestrial land was contaminated by oily mist fallout. Kuwait Institute for Scientific Research successfully tested and standardized bioremediation technology to significantly reduce petroleum oil contaminants in the soil. Preliminary results suggested that the bioremediated soil was capable of supporting plant growth without adverse effects. In the present study, growth of a number of ornamental plants in bioremediated soil was compared with that in normal agricultural soil to assess the suitability of bioremediated soil for use in landscape/greenery projects in Kuwait. Results indicated that the bioremediated soil did not affect the establishment of test plants, but influenced their growth to varying extents. Height increments in the bioremediated soil during the first 12 months in Dalbergia sissoo, Prosopis chiliensis, Olea europaea, Parkinsonia aculeata, and Conocarpus lancifolius was 6.2 to 72.9% higher than those in agricultural soil. In contrast, it adversely affected the height growth in Callistemin viminalis and Acacia acuminata and had no influence on plant height in Pithecellobium dulce. The average height increment in three shrubs (Clerodendron inerme, Bougainvillea glabra, and Vitex negundo) out of the six shrubs tested in the study, was two to three times higher in bioremediated soil than in agricultural soil. Growths were adversely affected in the three others (Bougainvillea sp., Simmondsia chinensis and Thevitia nerifolia). Based on the growth data, ornamental plants tested in the study were grouped into three categories: the first group consisted of plants whose growth was promoted in bioremediated soil; the second group included plants whose growth was not affected; and the third group comprised species that were sensitive to petroleum oil pollutants.

Predicting sheetwash and rill erosion over the Australian continent

Soil erosion is a major environmental issue in Australia. It reduces land productivity and has off-site effects of decreased water quality. Broad-scale spatially distributed soil erosion estimation is essential for prioritising erosion control programs and as a component of broader assessments of natural resource condition. This paper describes spatial modelling methods and results that predict sheetwash and rill erosion over the Australian continent using the revised universal soil loss equation (RUSLE) and spatial data layers for each of the contributing environmental factors. The RUSLE has been used before in this way but here we advance the quality of estimation. We use time series of remote sensing imagery and daily rainfall to incorporate the effects of seasonally varying cover and rainfall intensity, and use new digital maps of soil and terrain properties. The results are compared with a compilation of Australian erosion plot data, revealing an acceptable consistency between predictions and observations. The modelling results show that: (1) the northern part of Australia has greater erosion potential than the south; (2) erosion potential differs significantly between summer and winter; (3) the average erosion rate is 4.1 t/ha.year over the continent and about 2.9 × 109 tonnes of soil is moved annually which represents 3.9% of global soil erosion from 5% of world land area; and (4) the erosion rate has increased from 4 to 33 times on average for agricultural lands compared with most natural vegetated lands.

Removal of Trichloroethylene from Clay Soil by Series-Electrokinetic Process

The performance of a series-electrokinetic (EK) process in treating a clay soil artificially contaminated with 300 mg/kg trichloroethylene (TCE) was investigated. Constant voltage gradients of 1 or 2 V/cm to induce the movement of electrolyte solution in the soil were applied to the EK system for 3–5 days using synthetic groundwater as processing fluid. Results show that the values of electroosmotic permeability ranged from 3.7×10-6 to 9.1×10-6 cm2/V-s. Increasing applied voltage and prolonging processing time resulted in a better removal efficiency. With voltage gradient of 1 V/cm, TCE removal efficiency of 75.8 and 86.4% were achieved, respectively, for 3 and 5 days EK operation. It was found that nearly 100% TCE was removed in the vicinity of anode sides. When the applied voltage gradient was raised to 2 V/cm, the remaining TCE concentration in both cathode sides was effectively removed and a total removal efficiency of 91.3% was achieved. Energy requirements per unit ton of soil treated were around 12...

Estimating prokaryotic diversity and its limits.

The absolute diversity of prokaryotes is widely held to be unknown and unknowable at any scale in any environment. However, it is not necessary to count every species in a community to estimate the number of different taxa therein. It is sufficient to estimate the area under the species abundance curve for that environment. Log-normal species abundance curves are thought to characterize communities, such as bacteria, which exhibit highly dynamic and random growth. Thus, we are able to show that the diversity of prokaryotic communities may be related to the ratio of two measurable variables: the total number of individuals in the community and the abundance of the most abundant members of that community. We assume that either the least abundant species has an abundance of 1 or Preston's canonical hypothesis is valid. Consequently, we can estimate the bacterial diversity on a small scale (oceans 160 per ml; soil 6,400-38,000 per g; sewage works 70 per ml). We are also able to speculate about diversity at a larger scale, thus the entire bacterial diversity of the sea may be unlikely to exceed 2 x 10(6), while a ton of soil could contain 4 x 10(6) different taxa. These are preliminary estimates that may change as we gain a greater understanding of the nature of prokaryotic species abundance curves. Nevertheless, it is evident that local and global prokaryotic diversity can be understood through species abundance curves and purely experimental approaches to solving this conundrum will be fruitless.

Evaluating Agricultural Nonpoint‐Source Pollution Programs in Two Lake Erie Tributaries

During the past three decades, numerous government programs have encouraged Lake Erie basin farmers to adopt practices that reduce water pollution. The first section of this paper summarizes these state and federal government agricultural pollution abatement programs in watersheds of two prominent Lake Erie tributaries, the Maumee River and Sandusky River. Expenditures are summarized for each program, total expenditures in each county are estimated, and cost effectiveness of program expenditures (i.e., cost per metric ton of soil saved) are analyzed. Farmers received nearly $143 million as incentive payments to implement agricultural nonpoint source pollution abatement programs in the Maumee and Sandusky River watersheds from 1987 to 1997. About 95% of these funds was from federal sources. On average, these payments totaled about $7000 per farm or about $30 per farm acre (annualized equivalent of $2 per acre) within the watersheds. Our analysis raises questions about how efficiently these incentive payments were allocated. The majority of Agricultural Conservation Program (ACP) funds appear to have been spent on less cost-effective practices. Also, geographic areas with relatively low (high) soil erosion rates received relatively large (small) funding.

Soil quality audit for resource conservation in Indian agriculture

Indian agricultural enterprise is one of the largest in terms of human capital and area of operation. It covers approximately 144 mha arable land, more than 60% of the population, and accounts for 40 % of the GDP. Hence its role in overall economic ecological and social development is very critical. Indian agricultural scene is a mix of traditional, low input, subsistence agriculture by the resource-poor farmer and science-based, high-input intensive farming by the rich farmers. Both of them have a share in the impairment of the environment. Because pockets of very high input cultivation are still limited, the pollution due to agricultural waste, excess fertilizers and pesticides are still not as wide-spread and alarming as they are in the west. Soil loss and degradation is the most serious environmental concern generated by the harsh geographical features of the country and by agricultural enterprises, both exacerbated by over-straining animal and human population. Almost 70% of the geographical area is prone to water and wind erosion and other stresses. 5334 million tonnes of soil is eroded annually and 5.3-8.4 million tonnes of the plant nutrients are lost. If this trend continues, one-third of the arable land is likely to be lost. For the fragile and slopy lands, soil conservation measures are being taken up on an extensive scale through water shed approach. These, however, have not been very effective or friendly for over 78% of the small and marginal farmers. Soil Quality, a holistic concept encompassing productivity, environmental quality, and human and animal health, has been developed recently for validating and auditing sustainable agriculture. Several physical, chemical and biological indicators like pH, EC, nutrient status, infiltration rate, soil structure, soil organic carbon etc. have been identified as indicators for measuring soil quality. This approach can be initiated in some places in India to monitor the negative impacts of certain currently prevailing agricultural practices, and facilitate sustainable agriculture through alternate farming protocols. Locale specific, farmer-friendly and conducive packages should be evolved monitored and evaluated in collaboration with the small farmer so that soil resources are conserved or upgraded for future generations.

Dust in the Wind: Long Range Transport of Dust in the Atmosphere and Its Implications for Global Public and Ecosystem Health

Movement of soil particles in atmospheres is a normal planetary process. Images of Martian dust devils (wind-spouts) and dust storms captured by NASA's Pathfinder have demonstrated the significant role that storm activity plays in creating the red atmospheric haze of Mars. On Earth, desert soils moving in the atmosphere are responsible for the orange hues in brilliant sunrises and sunsets. In severe dust storm events, millions of tons of soil may be moved across great expanses of land and ocean. An emerging scientific interest in the process of soil transport in the Earth's atmosphere is in the field of public and ecosystem health. This article will address the benefits and the potential hazards associated with exposure to particle fallout as clouds of desert dust traverse the globe.

Conversion of soil remediating incinerators into industrial waste incinerators

Soil Remediating Incinerators (SRIs) in the United States (US) were primarily deployed at United States Environmental Protection Agency (USEPA) Superfund sites and sometimes at commercial sites in the last two decades. The remediation of these sites by incineration seemed to peak in the late 1980's and early 1990's. The decline in the use of these incinerators is due to changing economics (price per ton of soil processed), challenges in the system permitting and siting, competing technologies (such as high capacity direct and indirect-fired Thermal Desorption Systems), and the incorrect public perception that these systems endanger human health and pollute the environment. Many of these sophisticated, well-proven transportable units are currently idle while applications for them are being sought. Since the domestic market has changed, leading companies have started converting these units into Indus trial Waste Incinerators (IWIs) for international deployment. The primary issues for conversion are economic, regulatory and technical. The economic aspects include country-specific project financing issues and the sometimes high costs of retrofitting existing systems. Regulatory issues include stack gas, ash and wastewater discharge criteria. Some Asian and Latin American countries have more stringent criteria than those in the US, requiring expensive upgrade of air pollution controls. The technical challenges of waste preparation and feed systems for multiple-feed IWIs are significantly greater than those of single feed soil remediation systems. The waste feeds for IWIs are typically received in bulk shipments, tankers and drums; their physical proper ties present a variety of material handling challenges; and their compositions represent a wide range of complex waste profiles that further complicate meeting stringent discharge criteria. These issues, opportunities and challenges associated with conversion are discussed in this paper. Available data on the feed characteristics and performance of IWIs are also presented.

The use of poultry litter as co-substrate and source of inorganic nutrients and microorganisms for the ex situ biodegradation of petroleum compounds

The purpose of this investigation was to determine the feasibility of utilizing poultry litter as a source of microorganisms, C co-substrate, N, and P to enhance the biodegradation of petroleum compounds in contaminated soil. An initial laboratory-scale study utilized soil contaminated with approximately 3,000 mg/kg (ppm) total petroleum hydrocarbons (TPHC) as diesel fuel. Biotreatment units, each containing 10 L of contaminated soil, were supplemented (0, 1, 10, and 20%, total weight basis) with broiler litter containing 3.65% N and 1.89% P. Petroleum-degrading microorganisms previously enriched from broiler and turkey litter were also inoculated into the litter-treated units. A significant first order rate of TPHC biodegradation was measured for all treatment units containing broiler litter (P < 0.05). Based on these results, a subsequent study was conducted at the site of a commercial facility permitted to treat soil (ex situ) contaminated with hazardous compounds. Soil treatment plots, each containing approximately 1 ton of soil contaminated with approximately 1,200 to 1,600 mg/kg diesel fuel were established. Each plot was replicated four times and the experiment was conducted for 35 d. Treatments were as follows: control, soil only; soil + commercial blend of bioremediation nutrients; soil + commercial fertilizer; soil + poultry litter (1% by volume); soil + poultry litter (10% by volume); soil + pelleted poultry litter (10% by volume). The results showed that the remediation of soil contaminated with petroleum compounds is significantly (P < 0.05) enhanced when supplemented with poultry litter (pelleted or nonpelleted) in concentrations of 10% soil volume. These results demonstrate the potential for a specialized market for the use of poultry litter.

Ecology of Soil Erosion in Ecosystems

Each year, about 75 billion tons of soil are eroded from the world's terrestrial ecosystems. Most agricultural land in the world is losing soil at rates ranging from 13 tons/ha/year to 40 tons/ha/year. Because soil is formed very slowly, this means that soil is being lost 13–40 times faster than the rate of renewal and sustainability. Rain and wind energy are the two prime causes of erosion from tilled or bare land. Erosion occurs when the soil lacks protective vegetative cover. Soil erosion reduces the productivity of the land by loss of water, soil organic matter, nutrients, biota, and depth of soil. The greatest threat to providing food for a rapidly growing human population is soil erosion. Abandoned, eroded agricultural land is replaced by clearing forested ecosystems.

Process challenges in rotary kiln‐based incinerators in soil remediation projects

AbstractMost Superfund sites undergoing thermal remediation consist of high‐moisture content (15 to 40 percent) soils having light organic contamination (low‐heat content). In the early 1980s, the rotary kiln incinerators employed at these Superfund sites were relatively small mobile hazardous waste incinerators (HWI) built on standard‐size semi‐trailers. As the industry matured over the past ten years, competition has driven the industry to larger and more efficient rotary kiln systems that minimize the cost per ton of soil treated by increasing the throughput rates and shortening on‐site processing time.Because these units are transported from site to site by truck or a combination of rail and truck, the rotary kiln outside shell diameters have peaked to approximately 13.5 feet. Now the focus has shifted to increasing the processing capacity of these existing, maximized fixed‐sized systems. Such actions include the use of oxygen‐based combustion systems, which increase the throughput and efficiency by improving heat transfer and reducing the volume of combustion gas requiring treatment. However, despite the experience and expertise gained by the participants in the thermal remediation industry, many of the same process challenges still remain. Combustion gas particulate entrainment from a rotary kiln HWI is a key issue when thermally treating soils because of the slagging potential in the secondary combustion chamber (SCC) and/or the potential to overload the downstream incinerator wastewater treatment system (IWTS). Excessive infiltration air into the rotary kiln can reduce the rate of heat transfer to the solids bed and correspondingly reduce the overall processing rate. More stringent ash quality requirements require higher ash temperatures and longer solids retention time at temperature. Estimating metal emissions remains a challenge due to the limited availability of data on metal behavior in combustion systems. New and more stringent particulate, nitrogen oxides (NOx), metals, and dioxins/furans emissions performance requirements present additional challenges, as does a trend in towards zero‐liquid discharge from the air pollution control system.This article discusses these process challenges facing the industry and potential solutions, based on data from IT's Hybrid Thermal Treatment System® HTTS® and other sources.