Evaluation of Mechanisms of Alteration and Humification of PAHs for Water Quality Management

Introduction: Creosote-pentachlorophenol (PCP) is a mixture commonly used as a wood preservative in the U.S. (1). A 1988 survey (2) indicated that 1,397 wood preserving waste contaminated sites exist in the United States consisting of 555 active wood treatment plants and 842 inactive plants. Stinson (3) indentifed 58 wood preserving sites on the National Priorities List, of which 51 have PCP and/or creosote or polycyclic aromatic hydrocarbon (PAH) contamination. Principal classes of organic constituents present in creosote waste are PAHs (~85% by weight) and phenolics. PAHs with less than three fused benzene rings comprise 69% (i.e., naphthalene, anthracene and phenanthrene); PAHs with more than three rings, such as pyrne, benzo(a)pyrene, and benz(a)anthracene, dibenz(a,h)anthracene, and indeno(1,2,3-c,d)pyrene comprise 16% by weight of creosote. Phenolics comprise 2% to 17% of creosote. Nitrogen- and sulfur- containing heterocyclic compounds may comprise up to 13% of creosote by weight. Creosote and creosote components including phenol and several PAHs have been reported to be mutagenic, teratogenic, fetotoxic and/or toxic (4,5) and have been designated as hazardous wastes under the Resource Conservation and Recovery Act of 1976 (6) and as hazardous substances under the Comprehensive Environmental Response, Compensation, and Liability Act of 1980. PCP is often added to creosote to enhace the wood preservation potential due to its bactericidal and fungicidal properties. PCP is also toxic to lower and higher plants (algicide, herbicide), to invertegrate and vertebrate animals (insecticide, molluscicide), and to man. Toxicity of PCP and potentical for uptake by organisms are pH-dependent, since PCP is a weak acid with a Ka of about 10^-5. Both bioaccumulation and toxicity increase as pH decreases due to the greated penetration of cell membranes by non-ionized PCP molecules than by pentachlorophenate ions (1). Therefore PCP may inhibit microbial degradation of other compounds in creosote-PCP waste, including oil and grease. Contaminated vadose zone soil systems generally consist of four phases: 1)aqueous; 2) gas; 3) oil (commonly referred to as non-aqueous phase liquid, or NAPL); and 4)solid, which has two components, and inorganic mineral compartment and an organic matter compartment (organic carbon-humic substances). Interphase tranfer potential for waste constituents among oil (waste or NAPL), water, air, and solid (organic and inorganic) phase of a soil system is affected by the relative affinity of the waste constituents for each phase. Measurement of waste constitutents in all four phases is generally not done in treatability studies, especially in complex environmental samples (7). High molecular weight (greater than 3 rings) PAHs are hydrophobic and essentially not mobile dur to their low volatilities and water solubilities. Bulman et al. (8) and Keck et al. (9) observed that sorption of B(a)P to soil was the dominant mechanism of loss. Studies have shown that immobilization of some xenobiotics can be accomplished by incorporation into soil humus, or sorption into the clay lattice of soil (10). Humification and sorption have not been extensively evaluated for PAHs in creosote contaminated soil. PCP is, in general, more mobile in high pH soils than in acidic soils. At low pH, PCP exists as a free acid (non-ionized) and readily adsorbs to soil particles. At high pH, PCP exists in the ionized form (pKa = 4.7) as the negatively charged pentachlorophenate anion, and is more mobile. In a study by Choi and Aomine (11), apparent adsorption of PCP was greatest in strongly acid soil and in soils with high organic matter content. Apparent adsoprtion was shown to include both the mechanisms of adsorption on soil colloids and precipitation in the soil micelle and in the external liquid phase, depending on the soil pH. Pionteck (12) also observed that although soil organic matter is important in determining the extent of odsorption of PCP, an even more important soil property is pH. Adsorption of PCP was shown to be reversible. Therefore, PCP may not be permanently immobilized in the soil phase, but may be slowly released into and move through the soil (1). A wide range of soil organisms, including bacteria, fungi, cyanobacteria and eukaryotic algae, have been shown to have the enzymatic capacity to oxidize PAHs. Metabolites from the degradation of large PAHs identified in these studies are responsible for toxic, mutagenic, and/or carcinogenic responses in animal species and many indicate epoxide intermediates (13-20). Presense of PCP may inhibit microbial degradation of other organics, including PAHs, oil and grease, etc. Despite a high degree of chlorination, PCP has been shown to be degraded in soil. Microbial deconposition appears to be the primary detoxification mechanism. Success was the highest in those studies that used acclimated or inoculated (with acclimated species) systems. The ability to degrade PCP may not be uniform among microorganisms, and adaptation of microbial populations to PCP and control of pH may play important roles in its degradation (1). Laboratory studies (7, 12) of the biodegradation potential of creosote wood preservative waste have shown that hazardous parent components were degraded, transformed, or immobilized in certain soil systems. In a study by Aprill et al. (21) on the biodegradation potential of creosote, the apparent degradation of four non-carcinogenic PAHs and four carcinogenic PAHs ranged from 54% to 90% and 24% to 53% of mass added, respectively. Aprill et al. (21) defined apparent degradation as the measurement of changes in concentrations of specific constituents in solvent extracts of soil samples with time of incubation. The reduction in concentration of the higher molecular weight PAHs was correlated with oil and grease content of the waste. Degradation of a chemical in soil may not result in the complete mineralization of a hazardous waste, but may render waste constituents less harzardous or nonhazardous through transformations (1,7,21). However in some cases detoxification does not occur (22). Studies (23-30_ conducted with 14C labeled compounds often report collection of the radiolabelled carbon in carbon dioxide trapping solutions to indicate degradation or mineralization. However, collection of the radiolabelled carbon in a carbon dioxide trapping solution may be misleading in two ways, i.e., 1) liberation of CO2 may not be concurrent with complete degradation of the total mass present because of accumulation of metabolites in the soil (31), or 2) measurement of radiolabelled carbon may not indicate mineralization if colatilized parent compound or labeled metabolites are collected in the trapping solution in addition to 14C2 (32, 33). Torstensson and Stenstrom (31) recommend that the rate of decomposition of a substance should be defined by direct measurement of its disappearance. However, direct measurement of the disappearance of hydrophobic organics from soil systems cannot be defined as degration because of other loss mechanisms including volatilization or soption to soil solids. Sorbed organics that cannot be removed from soil by organic solvents cannot be easily identified or analyzed. There is a current lack of knowledge concering the behavior of PAHs in complex environmental vadose zone soil samples. This study was undertaken, using a chemical mass balance appreaoch, to determine the distribution of radiolabelled carbon, parent compounds, and transformation products of the radiolabelled PAH compounds, benzo(a)pyrene (B(a)P) and pyrene, among aqueous, gas, and solid phases of a non-contaminated and contaminated (creosote-PCP) vadose zone soil over time of incubation. The apparent degradation of unlabeled PAHs and changes in the toxicity of the water-soluble (aqueous) fraction were also measured

Ew gross! Recognition of Expressions of Disgust by Children With Obsessive-Compulsive Disorder

There is evidence suggesting that obsessive-compulsive disorder (OCD) in adults may be associated with an impaired ability to recognise the facial expression of disgust (Sprengelmeyer et al., 1997a; Woody, Corcoran, & Tolin, in press). It has been suggested that this impairment begins in childhood when the recognition of emotional expressions is being learnt (see Spengelmeyer et al., 1997a). This study compared the recognition of facial affect in children aged around 11 years with a diagnosis of obsessive-compulsive disorder (OCD; n = 11), other anxiety disorders (n = 20), and nonclinical children (n = 19), adapting the methodology of Sprengelmeyer et al. Disgust was most commonly misclassified as anger by children in all three groups. However, children with OCD did not show any evidence of a recognition deficit for disgust in comparison to either control group. Unexpectedly, however, children with OCD recognised expressions of surprise more accurately than nonclinical children. Recognition of disgust or any other emotion was not related to child self-reported anxiety symptoms. Given the observed differences in some studies with adults, future research may benefit by examining older adolescents and young adults to determine when these effects may first be notice

Archaeological Testing for a Proposed Landfill Expansion (Phase II) City of Del Rio, Val Verde County, Texas

During September 1989, a pedestrian survey was conducted within a I~S-acre tract acquired by the City of Del Rio, Val Verde County, for a landfill expansion project. The surface reconnaissance recorded one prehistoric site, 41 VV 1251. As a result, recommendation was made for Phase II subsurface testing. The Phase II subsurface testing, which included a geomorphic study, was accomplished during February 1990. Cultural resources were recovered indicating presence at site 41 VV 1251 from the Late Paleo-Indian period to the Late Archaic period. However, the site was determined to be almost totally deflated. The geomorphological tests verified this assessment and indicated no deeply buried deposits. Site 41 VV 1251 is not deemed potentially eligible for nomination to the National Register of Historic Places or for designation as a State Archeological Landmark

Aquilegia, Vol. 31 No. 1, Spring 2007, Newsletter of the Colorado Native Plant Society

https://epublications.regis.edu/aquilegia/1119/thumbnail.jp

Outcomes of safety and effectiveness in a multicenter randomized, controlled trial of whole-body hypothermia for neonatal hypoxic-ischemic encephalopathy.

BACKGROUND: Whole-body hypothermia reduced the frequency of death or moderate/severe disabilities in neonates with hypoxic-ischemic encephalopathy in a randomized, controlled multicenter trial. OBJECTIVE: Our goal was to evaluate outcomes of safety and effectiveness of hypothermia in infants up to 18 to 22 months of age. DESIGN/METHODS: A priori outcomes were evaluated between hypothermia (n = 102) and control (n = 106) groups. RESULTS: Encephalopathy attributable to causes other than hypoxia-ischemia at birth was not noted. Inotropic support (hypothermia, 59% of infants; control, 56% of infants) was similar during the 72-hour study intervention period in both groups. Need for blood transfusions (hypothermia, 24%; control, 24%), platelet transfusions (hypothermia, 20%; control, 12%), and volume expanders (hypothermia, 54%; control, 49%) was similar in the 2 groups. Among infants with persistent pulmonary hypertension (hypothermia, 25%; control, 22%), nitric-oxide use (hypothermia, 68%; control, 57%) and placement on extracorporeal membrane oxygenation (hypothermia, 4%; control, 9%) was similar between the 2 groups. Non-central nervous system organ dysfunctions occurred with similar frequency in the hypothermia (74%) and control (73%) groups. Rehospitalization occurred among 27% of the infants in the hypothermia group and 42% of infants in the control group. At 18 months, the hypothermia group had 24 deaths, 19 severe disabilities, and 2 moderate disabilities, whereas the control group had 38 deaths, 25 severe disabilities, and 1 moderate disability. Growth parameters were similar between survivors. No adverse outcomes were noted among infants receiving hypothermia with transient reduction of temperature below a target of 33.5 degrees C at initiation of cooling. There was a trend in reduction of frequency of all outcomes in the hypothermia group compared with the control group in both moderate and severe encephalopathy categories. CONCLUSIONS: Although not powered to test these secondary outcomes, whole-body hypothermia in infants with encephalopathy was safe and was associated with a consistent trend for decreasing frequency of each of the components of disability

The Cold Peace: Russo-Western Relations as a Mimetic Cold War

In 1989–1991 the geo-ideological contestation between two blocs was swept away, together with the ideology of civil war and its concomitant Cold War played out on the larger stage. Paradoxically, while the domestic sources of Cold War confrontation have been transcended, its external manifestations remain in the form of a ‘legacy’ geopolitical contest between the dominant hegemonic power (the United States) and a number of potential rising great powers, of which Russia is one. The post-revolutionary era is thus one of a ‘cold peace’. A cold peace is a mimetic cold war. In other words, while a cold war accepts the logic of conflict in the international system and between certain protagonists in particular, a cold peace reproduces the behavioural patterns of a cold war but suppresses acceptance of the logic of behaviour. A cold peace is accompanied by a singular stress on notions of victimhood for some and undigested and bitter victory for others. The perceived victim status of one set of actors provides the seedbed for renewed conflict, while the ‘victory’ of the others cannot be consolidated in some sort of relatively unchallenged post-conflict order. The ‘universalism’ of the victors is now challenged by Russia's neo-revisionist policy, including not so much the defence of Westphalian notions of sovereignty but the espousal of an international system with room for multiple systems (the Schmittean pluriverse)

Sclerosing angiomatoid nodular transformation of the spleen: CT, MR, PET, and 99mTc-sulfur colloid SPECT CT findings with gross and histopathological correlation

Sclerosing angiomatoid nodular transformation (SANT) is a benign, proliferative vascular lesion affecting the spleen. Few reports detailing the cross sectional and PET appearance of this lesion are available, and the lesion’s behavior with 99mTc-sulfur colloid scintigraphy is previously unreported. Sclerosing nodular transformation of the spleen shows increased tracer accumulation on positron emission tomography, and a central scar-like appearance with an enhancing capsule and radiating septae on CT and MR studies that reflects the gross and histopathological features of the lesion may be visible. An understanding of this pathological finding may allow prospective recognition of the sclerosing nodular transformation of the spleen on cross sectional imaging studies

Targeted Inhibition of miRNA Maturation with Morpholinos Reveals a Role for miR-375 in Pancreatic Islet Development

Several vertebrate microRNAs (miRNAs) have been implicated in cellular processes such as muscle differentiation, synapse function, and insulin secretion. In addition, analysis of Dicer null mutants has shown that miRNAs play a role in tissue morphogenesis. Nonetheless, only a few loss-of-function phenotypes for individual miRNAs have been described to date. Here, we introduce a quick and versatile method to interfere with miRNA function during zebrafish embryonic development. Morpholino oligonucleotides targeting the mature miRNA or the miRNA precursor specifically and temporally knock down miRNAs. Morpholinos can block processing of the primary miRNA (pri-miRNA) or the pre-miRNA, and they can inhibit the activity of the mature miRNA. We used this strategy to knock down 13 miRNAs conserved between zebrafish and mammals. For most miRNAs, this does not result in visible defects, but knockdown of miR-375 causes defects in the morphology of the pancreatic islet. Although the islet is still intact at 24 hours postfertilization, in later stages the islet cells become scattered. This phenotype can be recapitulated by independent control morpholinos targeting other sequences in the miR-375 precursor, excluding off-target effects as cause of the phenotype. The aberrant formation of the endocrine pancreas, caused by miR-375 knockdown, is one of the first loss-of-function phenotypes for an individual miRNA in vertebrate development. The miRNA knockdown strategy presented here will be widely used to unravel miRNA function in zebrafish