Effects of alum and aluminum chloride on phosphorus runoff from swine manure

Phosphorus (P) runoff from fields fertilized with swine (Sus scrofa domesticus) manure may contribute to eutrophication. The objective of this study was to evaluate the effect of aluminum sulfate (alum) and aluminum chloride applications to swine manure on P runoff from small plots cropped to tall fescue (Festuca arundinacea Shreb.). There were six treatments in this study: (i) unfertilized control plots, (ii) untreated manure, (iii) manure with alum at 215 mg Al L(-1), (iv) manure with aluminum chloride at 215 mg Al L(-1), (v) manure with alum at 430 mg Al L(-1), and (vi) manure with aluminum chloride at 430 mg Al L(-1). Manure application rates were equivalent to approximately 125 kg N ha(-1). Alum and aluminum chloride additions lowered soluble reactive phosphorus (SRP) levels from about 130 mg P L(-1) to approximately 30 mg P L(-1) at low rates. At high rates, SRP levels in swine manure were around 1 mg P L(-1). Soluble reactive P concentrations in runoff were 5.50, 3.66, 3.00, 0.87, 0.87, and 0.55 mg P L(-1), for normal manure, low alum, low aluminum chloride, high alum, high aluminum chloride, and unfertilized control plots, respectively. Hence, high alum and aluminum chloride reduced SRP concentrations in runoff by 84% and were not statistically different from SRP concentrations in runoff from unfertilized control plots. These data indicate that treating swine manure with alum or aluminum chloride could result in significant reductions in nonpoint-source P runoff.     

Bioavailability of biosolids molybdenum to soybean grain

Legumes grown in biosolids-amended soils and then fed to ruminants can represent problematic sources of molybdenum (Mo), but few field data are available to quantify the risk. We used a set of fields amended to high cumulative biosolids Mo loads (>18 kg ha(-1)) over 27 yr to generate additional data. Soybean [Glycine max (L.) Merr.] was grown on 29 fields (pH values>6.8) amended to a wide range of soil Mo loads. Soybean grain harvested from each field was analyzed for Mo and the concentrations regressed against soil Mo loads estimated from actual soil Mo concentrations in the 0- to 15-cm depth. Slopes of such linear regressions represent uptake coefficients (UC values) used by the USEPA to assess risk of biosolids Mo to ruminants fed forage grown on biosolids-amended land. The UC value for all 29 fields was estimated as 1.66, which agrees with the few soybean grain data in the literature. The UC value, however, is well below a conservative UC value of 4, recently recommended for all fresh legume materials fed to cattle. Soybean grain can contain high concentrations of Mo (>10 mg kg(-1)) and have low (<2:1) Cu to Mo ratios, which can exacerbate molybdenosis problems in cattle. However, soybean grain normally constitutes only -10% of dairy cattle diet, and other constituents (e.g., corn grain, stover, mineral supplements) are sufficient, or can be manipulated, to control molybdenosis.     

Enzymatic characterization of organic phosphorus in animal manure

Information on the forms of P present in animal manure may improve our ability to manage manure P. In most investigations of manure P composition, only inorganic and total P are determined, and the difference between them is assigned as organic P. In this study, we explored the possibility of identifying and quantifying more specific organic P forms in animal manure with orthophosphate-releasing enzymes. Pig (Sus scrofa) manure and cattle (Bos taurus) manure were first sequentially fractionated into water-soluble P, NaHCO3-soluble P, NaOH-soluble P, HCl-soluble P, and residual P. The fractions were separately incubated with wheat phytase, alkaline phosphatase, nuclease P1, nucleotide pyrophosphatase, or their combinations. The released orthophosphate was determined by a molybdate blue method. Part of the organic P in those fractions could be identified by the enzymatic treatments as phytate (i.e., 39% for pig manure and 17% for cattle manure in water-soluble organic P), simple phosphomonoesters (i.e., 43% for pig manure and 15% for cattle manure in NaOH-soluble organic P), nucleotide-like phosphodiesters (2-12%), and nucleotide pyrophosphate (0-4%). Our data indicate that the enzymatic treatment is an effective approach to identify and quantify the organic P forms present in animal manures.     

Ecological impacts of arable intensification in Europe

Although arable landscapes have a long history, environmental problems have accelerated in recent decades. The effects of these changes are usually externalized, being greater for society as a whole than for the farms on which they operate, and incentives to correct them are therefore largely lacking. Arable landscapes are valued by society beyond the farming community, but increased mechanization and farm size, simplification of crop rotations, and loss of non-crop features, have led to a reduction in landscape diversity. Low intensity arable systems have evolved a characteristic and diverse fauna and flora, but development of high input, simplified arable systems has been associated with a decline in biodiversity. Arable intensification has resulted in loss of non-crop habitats and simplification of plant and animal communities within crops, with consequent disruption to food chains and declines in many farmland species. Abandonment of arable management has also led to the replacement of such wildlife with more common and widespread species. Soils have deteriorated as a result of erosion, compaction, loss of organic matter and contamination with pesticides, and in some areas, heavy metals. Impacts on water are closely related to those on soils as nutrient and pesticide pollution of water results from surface runoff and subsurface flow, often associated with soil particles, which themselves have economic and ecological impacts. Nitrates and some pesticides also enter groundwater following leaching from arable land. Greatest impacts are associated with simplified, high input arable systems. Intensification of arable farming has been associated with pollution of air by pesticides, NO2 and CO2, while the loss of soil organic matter has reduced the system's capacity for carbon sequestration. International trade contributes to global climate change through long distance transport of arable inputs and products. The EU Rural Development Regulation (1257/99) provides an opportunity to implement measures for alleviating ecological impacts of arable management through a combination of cross-compliance and agri-environment schemes. To alleviate the problems described in this paper, such measures should take account of opportunities for public/private partnerships and should integrate social, cultural, economic and ecological objectives for multifunctional land use.     

Radiological impact from atmospheric releases of 238U and 226Ra from phosphate rock processing plants

Phosphate rocks are used extensively, mainly as a source of phosphorus for fertilizers and secondarily for phosphoric acid and other speciality chemicals. Phosphates are typically enriched in uranium and are thus one of the sources of technologically enhanced natural radiation (TENR) which increases exposure to man from natural radionuclides. Emissions from phosphate rock processing plants in gaseous and particulate form contain radionuclides, such as 238U and 226Ra, which are discharged into the environment causing radiation exposures to the population. About 10 MBq each of 238U and 226Ra are discharged into the environment each year from SICNG, a phosphate rock processing plant in Thessaloniki area, Northern Greece. The collective dose commitment to lung tissue resulting from atmospheric releases was estimated to be approximately 2 x 10(-9) person Gy t-1 for 238U and approximately 0.1 x 10(-9) person Gy t-1 for 226Ra, i.e. about 2 times higher than that estimated in the UNSCEAR reports issued in 1982, 1988, and 1993.     

Radon exhalation from uranium mill tailings: experimental validation of a 1-D model

TRACI, a model based on the physical mechanisms governing the migration of radon in unsaturated soils, has been developed to evaluate the radon flux density at the surface of uranium mill tailings. To check the validity of the TRACI model and the effectiveness of cover layers, an in situ study was launched in 1997 with the French uranium mining company, COGEMA. The study consisted of continuous measurements of moisture content, suction, radon concentration at various depths inside a UMT cover, and flux density at its surface. An initial analysis has shown that radon concentration and flux density, as calculated with a steady-state diffusion model using monthly averaged moisture contents, are in good agreement with measured monthly averaged concentrations and flux densities.     

Denitrification with acrylonitrile as a substrate using pure bacteria cultures isolated from acrylonitrile-butadiene-styrene wastewater

This study attempted to isolate and identify the denitrifying bacteria that utilize acrylonitrile as a substrate from acrylonitrile-butadiene-styrene (ABS) resin wastewater. The performance of the denitrifying bacteria for treating different initial acrylonitrile concentrations was also investigated under anoxic conditions. The results showed that seven strains of denitrifying bacteria that can use acrylonitrile or acrylic acid as a substrate were isolated from the denitrification tank of a wastewater treatment plant in a ABS resin manufacturing plant and a lab-scale anoxic granular activated carbon-fluidized bed. The bacteria strains Acidovorax facilis B and Pseudomonas nautica could utilize acrylonitrile up to 279 mg/l as a substrate for denitrification. For complete nitrate removal, an adequate supply of acrylonitrile was necessary. Under the assumption that the acrylic acid would be completely removed, the removal of 1 mg/l nitrate by A. facilis B or P. nautica, about 0.64-0.74 mg/l acrylonitrile or 0.87-1 mg/l acrylic acid was needed. Because strains A. facilis B and P. nautica could utilize acrylonitrile for denitrification, they are expected to play an important role in the treatment of acrylonitrile in the wastewater treatment plant (denitrification and nitrification processes) and lab-scale granular activated carbon-fluidized bed.     

Modelling the resilience of Australian savanna systems to grazing impacts.

Savannas occur across all of northern Australia and are extensively used as rangelands. A recent surge in live cattle exports to Southeast Asia has caused excessive grazing impacts in some areas, especially near watering points. An important ecological and management question is "how resilient are savanna ecosystems to grazing disturbances?" Resilience refers to the ability of an ecosystem to remain in its current state (resist change) and return to this state (recover) if disturbed. Resilience responses can be measured using field data. These responses can then be modelled to predict the likely resistance and recovery of savannas to grazing impacts occurring under different climatic conditions. Two approaches were used to model resilience responses. First, a relatively simple mathematical model based on a sigmoid response function was used. This model proved useful for comparing the relative resilience of different savanna ecosystems, but was limited to ecosystems and conditions for which data were available. Second, a complex process model, SAVANNA, was parameterised to simulate the structure and function of Australian savannas. Simulations were run for 50 years at two levels of grazing to evaluate resistance and then for another 50 years with no grazing to evaluate recovery. These runs predicted that savanna grasslands were more resistant to grazing (changed less) than red-loam woodlands, which recovered relatively slowly from grazing impacts. The SAVANNA model also predicted that these woodlands would recover slightly slower under the climate change scenario projected for northern Australia.     

Monitoring, enforcement, and the choice of environmental policy instruments

How to choose among the dozen policy instruments available to environmental management agencies has been a matter of concern and debate among environmental economists for the entire life of the profession – nearly four decades. The ability, or lack of it, to measure the quantities or observe the actions made "enforceable" by particular policy instruments ought clearly to be central to this choice. However, all too often the monitoring problem has been assumed away. When it is reintroduced in realistic forms, we find, not surprisingly, that some favorite policy instruments, such as pollution charges, are not applicable to some important problems, such as runoff pollution from farms; that marginal subsidies, by changing the burden of proof, may no longer be symmetric with charges; and that the apparent freedom from monitoring requirements of the newly fashionable instrument involving the public provision of information about firms or products is "paid for" by our inability to say anything about its performance on other dimensions that are also of interest. Electronic Publication