Relationships between soil physicochemical, microbiological properties, and nutrient release in buffer soils compared to field soils

The retention of nutrients in narrow, vegetated riparian buffer strips (VBS) is uncertain and underlying processes are poorly understood. Evidence suggests that buffer soils are poor at retaining dissolved nutrients, especially phosphorus (P), necessitating management actions if P retention is not to be compromised. We sampled 19 buffer strips and adjacent arable field soils. Differences in nutrient retention between buffer and field soils were determined using a combined assay for release of dissolved P, N, and C forms and particulate P. We then explored these differences in relation to changes in soil bulk density (BD), moisture, organic matter by loss on ignition (OM), and altered microbial diversity using molecular fingerprinting (terminal restriction fragment length polymorphism [TRFLP]). Buffer soils had significantly greater soil OM (89% of sites), moisture content (95%), and water-soluble nutrient concentrations for dissolved organic C (80%), dissolved organic N (80%), dissolved organic P (55%), and soluble reactive P (70%). Buffer soils had consistently smaller bulk densities than field soils. Soil fine particle release was generally greater for field than buffer soils. Significantly smaller soil bulk density in buffer soils than in adjacent fields indicated increased porosity and infiltration in buffers. Bacterial, archaeal, and fungal communities showed altered diversity between the buffer and field soils, with significant relationships with soil BD, moisture, OM, and increased solubility of buffer nutrients. Current soil conditions in VBS appear to be leading to potentially enhanced nutrient leaching via increasing solubility of C, N, and P. Manipulating soil microbial conditions (by management of soil moisture, vegetation type, and cover) may provide options for increasing the buffer storage for key nutrients such as P without increasing leaching to adjacent streams.     

Thermal Encapsulation of Metals in Superfund Soils

Abstract

Superfund sites frequently contain both heavy metals and organic hazardous waste. If not properly controlled, the metals may be changed to a more leachable form and may also be emitted to the atmosphere via the exhaust stack. This paper documents a batch kiln R&D test program to solve these metal-related problems. It was performed under the U.S. EPA’s SITE (Superfund Innovative Technology Evaluation) Emerging Technology Program. Allis Mineral Systems has developed the Thermal Encapsulation Process. Metals with limits set by EPA’s TCLP (Toxicity Characteristic Leaching Procedure) test and BIF (boiler and industrial furnace) stack emission regulations, such as cadmium, chromium, and lead, are the initial target of this process. This process, while unproven in these areas, may also apply to mixed waste (EPA hazardous waste/low-level radioactive wastes) and may also benefit commercial hazardous waste or Superfund thermal treatment systems. The results of the SITE tests were positive: strong, durable nodules were produced with excellent crush strength and improved resistance to leaching. Feed preparation, particularly control of moisture content, was found to be a key element in initiation of agglomeration. A good correlation was found between decreasing TCLP metals leachate levels and increasing crush strength.     

Conflicts between biodiversity conservation and human activities in the central and eastern European countries

Conflicts between the conservation of biodiversity and other human activities have been and continue to be of increasing concern in the European Union, often having important political, economic, and environmental repercussions. These conflicts have been addressed in the European Union by using a wide array of top down and bottom up tools, with varying degrees of success. A new challenge is now facing Europe with the integration of 10 new countries in the European Union (EU) and an additional range of biodiversity-rich habitats placed under EU legislation. The rich biodiversity of the central and eastern European countries (CEEC) is likely to be threatened by some aspects of the integration process, and conflicts between the conservation of biodiversity and other human activities are expected. In this paper, we review certain existing conflicts between biodiversity conservation and human activities in the CEEC, expected conflicts associated with integration to the EU, particularly in terms of new policy and legislation implementation, and, finally, explore possible conflict management options.     

Solubilization, solution equilibria, and biodegradation of PAH's under thermophilic conditions

Biodegradation rates of PAHs are typically low at mesophilic conditions and it is believed that the kinetics of degradation is controlled by PAH solubility and mass transfer rates. Solubility tests were performed on phenanthrene, fluorene and fluoranthene at 20 degrees C, 40 degrees C and 60 degrees C and, as expected, a significant increase in the equilibrium solubility concentration and of the rate of dissolution of these polycyclic aromatic hydrocarbons (PAHs) was observed with increasing temperature. A first-order model was used to describe the PAH dissolution kinetics and the thermodynamic property changes associated with the dissolution process (enthalpy, entropy and Gibb's free energy of solution) were evaluated. Further, other relevant thermodynamic properties for these PAHs, including the activity coefficients at infinite dilution, Henry's law constants and octanol-water partition coefficients, were calculated in the temperature range 20-60 degrees C. In parallel with the dissolution studies, three thermophilic Geobacilli were isolated from compost that grew on phenanthrene at 60 degrees C and degraded the PAH more rapidly than other reported mesophiles. Our results show that while solubilization rates of PAHs are significantly enhanced at elevated temperatures, the biodegradation of PAHs under thermophilic conditions is likely mass transfer limited due to enhanced degradation rates.     

Spatial and temporal analysis of pharmaceutical concentrations in the upper Tennessee River basin

The behavior of pharmaceutical compounds in aquatic ecosystems is not well defined. In order to determine spatial and temporal variations in concentrations of pharmaceuticals in the Tennessee River, water samples were collected from multiple points along the river and at the inflow of major tributaries. Sampling structure was designed to investigate trends between surface and subsurface samples, seasonal trends (winter, spring, summer, and fall), the direct influence of sewage treatment plants (upstream versus downstream), and the effect of downstream distance on pharmaceutical concentrations. All samples were quantified via solid phase extraction followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). This method yielded reproducible quantitation at low parts per trillion (ng L(-1)) levels for all 14 analytes (acetaminophen, atorvastatin, caffeine, carbamazepine, ciprofloxacin, diltiazem, fluoxetine, levofloxacin, lovastatin, norfluoxetine, ranitidine, sertraline, sulfamethoxazole, and trimethoprim). Correlation analyses (depth, distance) and repeated-measures ANOVAs (season, sewage treatment plant proximity) were used to determine statistically significant trends for frequently detected pharmaceuticals (caffeine, carbamazepine, sulfamethoxazole). Caffeine and sulfamethoxazole were found to vary by season in subsurface samples; spring exhibited the highest concentrations. Carbamazepine varied in proximity to sewage treatment plant outfall with subsurface samples yielding greater concentrations downstream than upstream. In addition, individual pharmaceuticals displayed positive correlation between surface and subsurface samples and negative correlation with downstream distance from the headwaters.     

Mitochondrial dysfunction, oxidative stress and apoptotic induction in microglial BV-2 cells treated with sodium arsenate

The treatment of microglial BV-2 cells with sodium arsenate(As(V):0.1-400 μmol/L — 48 hr)induces a dose-dependent response.The neurotoxic effects of high concentrations of As(V)(100,200 and 400 μmol/L) are characterized by increased levels of mitochondrial complexesⅠ,Ⅱ,and Ⅳ followed by increased superoxide anion generation.Moreover,As(V) triggers an apoptotic mode of cell death,demonstrated by an apoptotic SubG1 peak,associated with an alteration of plasma membrane integrity.There is also a decrease in transmembrane mitochondrial potential and mitochondrial adenosine triphosphate ATP.It is therefore tempting to speculate that As(V) triggers mitochondrial dysfunction,which may lead to defective oxidative phosphorylation subsequently causing mitochondrial oxidative damage,which in turn induces an apoptotic mode of cell death.     

URBANIZATION INFLUENCES ON AQUATIC COMMUNITIES IN NORTHEASTERN ILLINOIS STREAMS1

ABSTRACT: Biotic indices and sediment trace element concentrations for 43 streams in northeastern Illinois (Chicago area) from the 1980s and 1990s were examined along an agricultural to urban land cover gradient to explore the relations among biotic integrity, sediment chemistry, and urbanization. The Illinois fish Alternative Index of Biotic Integrity (AIBI) ranged from poor to excellent in agricultural/rural streams, but streams with more than 10 percent watershed urban land (about 500 people/mi²) had fair or poor index scores. A macroinvertebrate index (MBI) showed similar trends. A qualitative habitat index (PIBI) did not correlate to either urban indicator. The AIBI and MBI correlated with urban associated sediment trace element concentrations. Elevated copper concentrations in sediment occurred in streams with greater than 40 percent watershed urban land. The number of intolerant fish species and modified index of biotic integrity scores increased in some rural, urbanizing, and urban streams from the 1980s to 1990s, with the largest increases occurring in rural streams with loamy/sandy surficial deposits. However, smaller increases also occurred in urban streams with clayey surficial deposits and over 50 percent watershed urban land. These data illustrate the potentially complex spatial and temporal relations among biotic integrity, sediment chemistry, watershed urban land, population density, and regional and local geologic setting.