RESUMEN
While creosote components have very low water solubility, concerns have been raised about potential environmental effects and stimulated research to minimize migration. Best management practices have been developed but there are few data quantifying their effects. The effects of post-treatment steaming on migration of polycyclic aromatic hydrocarbons (PAHs) from horizontally oriented creosote treated southern pine decking subjected to simulated rainfall were examined. Twelve of the 16 PAHs examined were detected in runoff during the rainfall exposure but at concentrations well below those predicted by water solubility. PAH levels declined with increasing rainfall time, although the differences were sometimes slight. Steaming for 1 h had minimal effect on PAH levels in runoff while 3 h of steaming produced more noticeable reductions ranging from ~20 to 80% for naphthalene, acenaphthylene, and acenaphthene. Longer post-treatment steaming times reduced initial losses of creosote components from treated wood.
Asunto(s)
Creosota , Hidrocarburos Policíclicos Aromáticos , MaderaRESUMEN
The ability of standard soils to capture heavy metals or polycyclic aromatic hydrocarbons (PAHs) from ammoniacal copper zinc arsenate (ACZA)- or creosote-treated wood, respectively, was assessed using pressure-treated posts immersed in a freshwater pond. The soil, in heat-sealed, permeable plastic mesh sachets, was able to intercept copper, zinc, arsenic, and PAHs migrating from the posts. Chemical levels were much higher immediately adjacent to the posts and declined with distance from the posts. Metals were consistently detected around ACZA-treated posts, while 10 of the 16 EPA priority pollutants were detected in at least one sachet embedded around creosote-treated posts at each sampling point. These results were consistent with traditional sediment sampling methods. The primary advantages of the sachets were their consistency in terms of soil characteristics and the ease with which they could be retrieved from the pond. Further studies are planned to better understand the role of soil characteristics in the sachets on the ability to capture migrating preservatives.
Asunto(s)
Monitoreo del Ambiente/métodos , Restauración y Remediación Ambiental/métodos , Hidrocarburos Policíclicos Aromáticos/análisis , Contaminantes del Suelo/análisis , Suelo/química , Madera/química , Arseniatos/análisis , Cobre/análisis , Creosota/análisis , Restauración y Remediación Ambiental/instrumentación , Diseño de Equipo , Polímeros/química , Zinc/análisisRESUMEN
Pigments from wood-decay fungi (specifically spalting fungi) have a long history of use in wood art, and have become relevant in modern science due to their longevity and colorfastness. They are presently under investigation as colorants for wood, bamboo, oils, paints and textiles. Major hurdles to their commercialization have been color repeatability (in that the same strain of the same species of fungus may produce different colors over time), and the binding of the pigments to glass storage containers. This is persistent as they do not naturally exist in a loose form. Due to these issues, the 'standard' color for each was historically determined not by the amount of pigment, but by the color in a solution of dichloromethane (DCM), using the CIE L*a*b colorspace. This method of standardization severely limited the use of these pigments in industrial applications, as without a dry form, standard methodologies for repeatable color processing into other materials could not be easily implemented. Recent studies have developed a method to crystalize the red pigment from Scytalidium cuboideum (Sacc. & Ellis) Sigler & Kang, producing a highly pure (99%) solid crystal named 'Dramada'. Herein a method is detailed to compare the molarity of this crystallized pigment to variations in the color, to determine a color saturation curve (by weight) for the pigment from S. cuboideum in DCM and acetone. The molarities for this experiment ranged from 0.024 mM to 19 mM. Each molarity was color read and assigned a CIEL*a*b* value. The results showed that there was a correlation between the molarity and color difference, with the maximum red color occurring between 0.73 mM and 7.3 mM in DCM and between 0.97 mM to 0.73 mM in acetone. Extremely low molarities of pigment produced strong coloration in the solvent, and changes in molarity significantly affected the color of the solution. Having a saturation and color curve for the crystal 'Dramada' from S. cuboideum will allow for the reliable production of distinct colors from a known quantity (by weight) of pigment, erasing the final hurdle towards commercial development of the crystallized pigment from S. cuboideum as an industrial dyestuff.
Asunto(s)
Ascomicetos/química , Pigmentos Biológicos/química , Colorantes/química , Cromatografía de Gases y Espectrometría de Masas , Espectroscopía de Resonancia MagnéticaRESUMEN
Many lake ecosystems worldwide experience severe eutrophication and associated harmful blooms of cyanobacteria due to high loadings of phosphorus (P). While aluminum sulfate (alum) has been used for decades as chemical treatment of eutrophic waters, the ecological effects of alum on coupled metal and nutrient cycling are not well known. The objective of our study was to investigate the effects of an in-situ alum treatment on aluminum and nutrient (P, N, and S) cycling in a hypereutrophic lake ecosystem. Our results indicate that the addition of alum along with sodium aluminate (as a buffer) increased dissolved aluminum and sulfate in the surface and pore waters, and altered nitrogen cycling by increasing nitrous oxide (N2O) concentrations in the surface water. The increase of aluminum and sulfate may potentially feedback to alter benthic community dynamics. These results enhance our understanding of the unintended ecological consequences of alum treatments in hypereutrophic freshwater ecosystems.
Asunto(s)
Compuestos de Alumbre/análisis , Fenómenos Ecológicos y Ambientales , Monitoreo del Ambiente , Eutrofización , Lagos/química , Contaminantes Químicos del Agua/análisis , Cianobacterias/crecimiento & desarrollo , Ecosistema , Lagos/microbiología , Nitrógeno/análisis , Fósforo/análisisRESUMEN
Emissions from coal-fired power plants are the major anthropogenic source of mercury (Hg) in the environment. Because emitted Hg can be deposited near the source, concerns arise about the effects of coal-burning facilities on levels of toxic methylmercury (MeHg) in biota near such sources. We investigated the potential impact of a large Hg-emitting (450 kg in 2005) coal-fired power station in Conesville, Ohio, on MeHg levels in adult mosquitoes near the plant. In July 2010, mosquitoes were sampled at 23 locations within a 60-km radius of the plant and at three reference sites distant from major combustion sources of Hg. Nearly all of the Hg in mosquitoes appeared in the form of MeHg (mean=91%). Concentrations of MeHg in mosquitoes were unrelated to either distance or direction from the Conesville plant and did not differ from those at the three reference sites. Moreover, measured levels of MeHg in mosquitoes near Conesville are in good agreement with those predicted from an empirical relationship to wet atmospheric Hg fluxes alone. This suggests that either little of the Hg emitted from the Conesville plant is deposited locally or near-source deposition of Hg does not have a significant impact on MeHg in mosquitoes and, by extension, other insects with similar life histories in the local food web.