Alterations in land surface-atmosphere processes resulting from the 1988 Greater Yellowstone Area fires.

Meteorological observations for the 10-year period 1984 to 1993 have been collected from 178 stations within the GYA, quality assured, and spatially and temporally interpolated to produce gridded data suitable for model input. These data comprise 8-km resolution hourly values of seven meteorological variables: near-surface air temperature, relative humidity, precipitation, wind speed, atmospheric pressure, and downwelling solar and longwave radiation.New algorithms for modeling of snow and frozen soil have been implemented in the Simulator for Hydrology and Energy Exchange at the Land Surface (SHEELS) model. These added capabilities, necessary for using the SHEELS model in the GYA, allow for the hydrologic, thermal, and albedo effects of snow cover and frozen soil to be realized in model output.Substantial alterations of the latent and sensible heat fluxes were found to result from the removal of vegetation by the 1988 fires. Specifically, latent heat flux was decreased and sensible heat flux increased in the burn area. Furthermore, these effects also were seen downwind of the burn area, indicating that regional climate may have been affected by the fires. Soil moisture was not substantially affected by the fire-induced vegetation changes, however.The SHEELS model was then used to examine surface energy budget and soil moisture variables before and after the 1988 fires. Four datasets of these variables were produced for each of three regions within the GYA: a burn area consisting of fire-affected regions, an area upwind of the burn area, and an area downwind from the burn area. The four datasets provide a basis for differentiation among possible causes of any observed alterations in surface energy budget or soil moisture variables and result from varying the vegetation or meteorological model forcing.During the late summer of 1988, wildland fires in Yellowstone National Park and the surrounding Greater Yellowstone Area (GYA) burned approximately 570,000 ha. The dramatic alteration in land cover resulting from these fires coupled with the availability of surface and satellite data necessary for modeling land surface-atmosphere processes provides an ideal opportunity to study the effects of fire-induced vegetation changes on surface energy budget variables and soil moisture

Wordsworth\u27s Mother Tongue: Identification, Separation, and Recognition.

This psychoanalytic study complicates prevailing notions about William Wordsworth\u27s representations of mothers. Wordsworth does not invariably conflate mothers with Nature or consistently construct women as silent objects of male quest. Rather, he explores a variety of mothers\u27 voices, often associating them with language acquisition and poetic composition. In early work he acknowledges mothers\u27 significance directly and creates more vocal mothers, while in later work and revisions he often conceals mothers\u27 significance and depicts more object-like mothers. In the 1805 version of book two of The Prelude, Wordsworth recalls himself as a blessed babe who recognizes his mother as a separate subject. From this relationship, the babe derives the creative and receptive powers of the poetic spirit and expands the development of poetic powers to the relationship between child and a Nature personified as a mother. In the 1850 version of book two, however, he objectifies the mother and Nature and reduces their explicit significance on the poetic spirit. The dynamic of similitude in dissimilitude, which Wordsworth discusses in The Preface to Lyrical Ballads and which structures much of his poetic theory, is rooted in the mother-child experience of recognition described in The Prelude. Wordsworth splits off mother associations in later revisions, but an ungendered maternal dynamic remains as the matrix for his definition of the Poet. In Her Eyes Are Wild, Wordsworth experiments with a mother\u27s voice to depict a filial relationship. He demonstrates the consequences of a mother\u27s over-identification with her child and implies what might happen when poets over-identify with their subjects. In later editions the balladeer finds a more stable voice by identifying with the mother and maintaining self-awareness; however, the mother never achieves such balance. In The Sailor\u27s Mother, The Emigrant Mother, The Affliction of Margaret, The Force of Prayer, and The Widow on Windermere, Wordsworth represents mothers physically separated from their children by distance or death and explores how they resist separation through mourning. The way these mothers articulate their desires often resembles the way poets construct poems: both strive to recollect persons or re-order experiences to accept separation and maintain a sense of connection

Accumulation of toxic organic pollutants in the blue crab Callinectes sapidus (aromatic hydrocarbons, gas chromatography, polychlorinated biphenyls, Virginia)

Levels of toxic organic pollutants (TOP) were examined in the blue crabs, Callinectes sapidus, of Virginia waters. Alkyl substituted polynuclear aromatic hydrocarbons (ASPAH), thought derived from weathered petroleum, were the most common organic pollutants present. Unsubstituted aromatics, heterosubstituted aromatics, polychlorinated biphenyls (PCB), and DDT metabolites were also detected by the analytical procedure employed. Highest levels of ASPAH were found in crabs from the heavily industrialized Hampton Roads area of the James River. Lower concentrations were detected in crabs from the Pocomoke Sound, the upper James and the Rappahannock River sampling sites. PCB levels were elevated in samples taken from both James River stations. Levels of TOP were generally higher in crabs sampled in June than in September of 1981. Concentrations of pollutants in the tissues and tissue lipid content were correlated. Highest levels of both were detected in the hepatopancreas, followed by egg, ovary and muscle. TOP levels in field samples and in-vivo biotransformation of the model compound benzo(a)pyrene (B(a)P) in the hepatopancreas, during in-laboratory experiments, suggested that differences may exist in the uptake and elimination of pollutants as a function of the sex and maturity of the crabs. It appeared that the metabolism of aromatic hydrocarbons varied with the molt stage of the crabs. A variety of polar metabolites of tritium labeled B(a)P were detected in the hepatopancreas of blue crabs, when examined by normal and reverse phase high performance liquid chromatography. In conclusion, to accurately assess the levels and effects of TOP in biota from the field, several factors must be considered. Among these are the species and tissues examined, the sex, maturity and condition of the individuals selected for analysis, and the location and season of sampling

Bioavailability of Organic Pollutants to Aquatic Organisms

Settlement of the Chesapeake Bay region began in earnest in the early 17th century. The native American population and early colonists were impressed by the abundance of fish and shellfish and located their population centers to take advantage of these and other natu!al resources. Introduction of wastes into the bay was coincident with this settlement. As the human population increased, so did the pressure on the ecological system. In the 20th century significant quantities of synthetic chemicals began to be introduced, many of which were toxic and nonbiodegradable [Faust and Hunter 1971]. Today the areas surrounding the bay are experiencing unprecedented development; introduction of toxic organic pollutants has correspondingly increased. Water quality and the abundance of many aquatic organisms have suffered accordingly [O\u27Connor and Huggett 1988].https://scholarworks.wm.edu/vimsbooks/1177/thumbnail.jp

Single-Use Plastics and COVID-19: Scientific Evidence and Environmental Regulations

Waste plastics are a serious and growing environmental problem. Less than 10% of plastics are recycled, with most discarded in landfills, incinerated, or simply abandoned.1 Single-use plastics constitute about half of plastic waste. While most plastics are used and initially disposed of on land, much eventually enters aquatic ecosystems.2 Wildlife mortalities result from encounters (e.g., ingestion and entanglement) with large debris, including plastic bags. Such bags are excluded from many recycling programs, as they can entangle machinery. Most plastics do not readily biodegrade in the environment. However, they can be embrittled by UV exposure and fragment into microplastics (mm) and nanoplastics

Influence of a suite of environmentally relevant conditions on PBT leaching from, and sorption to, marine microplastic debris

Synthetic polymers (plastics) enter marine environments from terrestrial and marine-based sources. The manner of release, the plastic’s composition/properties and ambient marine conditions determine debris fate and its impacts on living resources. It was long assumed that all plastics were persistent and inert, possessing negligible potential for chemical impacts. However, in reality, commercial polymers exhibit a range of potentials for interactions. Persistent, bioaccumulative and toxic (PBT) chemicals are lipophilic and may concentrate from ambient waters by orders of magnitude on polymer surfaces (Teuten et al., 2007). The type of polymer affects the degree of PBT sorption. Indeed, plastics have been found useful as passive samplers for measuring ambient concentrations of PBTs. Polymers also may be affected chemically or physically by weathering, e.g. exposure to ultraviolet (UV) radiation (Andrady, 2011), or fragmentation by abrasion, such as on a beach. While additives can leach from plastics into the water, migration studies pertinent to the marine environment are rare. The picture is complicated further as weathering itself may alter the extent of PBT leaching and sorption. More ...

Strategies for assessing the implications of malformed frogs for environmental health

The recent increase in the incidence of deformities among natural frog populations has raised concern about the state of the environment and the possible impact of unidentified causative agents on the health of wildlife and human populations. An open workshop on Strategies for Assessing the Implications of Malformed Frogs for Environmental Health was convened on 4-5 December 1997 at the National Institute of Environmental Health Sciences in Research Triangle Park, North Carolina. The purpose of the workshop was to share information among a multidisciplinary group with scientific interest and responsibility for human and environmental health at the federal and state level. Discussions highlighted possible causes and recent findings directly related to frog deformities and provided insight into problems and strategies applicable to continuing investigation in several areas. Possible causes of the deformities were evaluated in terms of diagnostics performed on field amphibians, biologic mechanisms that can lead to the types of malformations observed, and parallel laboratory and field studies. Hydrogeochemistry must be more integrated into environmental toxicology because of the pivotal role of the aquatic environment and the importance of faces and transport relative to any potential exposure. There is no indication of whether there may be a human health factor associated with the deformities. However, the possibility that causal agents may be waterborne indicates a need to identify the relevant factors and establish the relationship between environmental and human health in terms of hazard assessment

Sorption of representative organic contaminants on microplastics: Effects of chemical physicochemical properties, particle size, and biofilm presence

Microplastic pollution has attracted mounting concerns worldwide. Microplastics may concentrate organic and metallic contaminants; thus, affecting their transport, fate and organismal exposure. To better understand organic contaminant-microplastic interactions, our study explored the sorption of selected polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), α-hexabromocyclododecane (α-HBCDD), and organophosphate flame retardants (OPFRs) on high-density polyethylene (HDPE) and polyvinylchloride (PVC) microplastics under saline conditions. Sorption isotherms determined varied between chemicals and between HDPE and PVC microplastics. Log Freundlich sorption coefficients (Log KF) for the targeted chemicals ranged from 2.01 to 5.27 L kg-1 for HDPE, but were significantly lower for PVC, i.e., ranging from Log KF data (2.84 – 8.58 L kg-1). Significant correlations between chemicals’ Log KF and Log Kow (octanol-water partition coefficient) indicate that chemical-dependent sorption was largely influenced by their hydrophobicity. Sorption was evaluated using three size classes (\u3c 53, 53 – 300, and 300 – 1000 µm) of lab-fragmented microplastics. Particle size did not significantly affect sorption isotherms, but influenced the time to reach equilibrium and the predicted maximum sorption, likely related to microplastic surface areas. The presence of biofilms on HDPE particles significantly enhanced contaminant sorption capacity, indicating more complex sorption dynamics in the chemical-biofilm-microplastic system. Our findings offer new insights into the chemical-microplastic interactions in marine environment

Microplastics affect sedimentary microbial communities and nitrogen cycling

Microplastics are ubiquitous in estuarine, coastal, and deep sea sediments. The impacts of microplastics on sedimentary microbial ecosystems and biogeochemical carbon and nitrogen cycles, however, have not been well reported. To evaluate if microplastics influence the composition and function of sedimentary microbial communities, we conducted a microcosm experiment using salt marsh sediment amended with polyethylene (PE), polyvinyl chloride(PVC), polyurethane foam (PUF) or polylactic acid (PLA) microplastics. We report that the presence of microplastics alters sediment microbial community composition and nitrogen cycling processes. Compared to control sediments without microplastic, PUF- and PLA-amended sediments promote nitrification and denitrification, while PVC amendment inhibits both processes. These results indicate that nitrogen cycling processes in sediments can be significantly affected by different microplastics, which may serve as organic carbon substrates for microbial communities. Considering this evidence and increasing microplastic pollution, the impact of plastics on global ecosystems and biogeochemical cycling merits critical investigation

Human Indoor Exposure to Airborne Halogenated Flame Retardants: Influence of Airborne Particle Size

Inhalation of halogenated flame-retardants (HFRs) released from consumer products is an important route of exposure. However, not all airborne HFRs are respirable, and thus interact with vascular membranes within the gas exchange (alveolar) region of the lung. HFRs associated with large (\u3e 4 mu m), inhalable airborne particulates are trapped on the mucosal lining of the respiratory tract and then are expelled or swallowed. The latter may contribute to internal exposure via desorption from particles in the digestive tract. Exposures may also be underestimated if personal activities that re-suspend particles into the breathing zone are not taken into account. Here, samples were collected using personal air samplers, clipped to the participants\u27 shirt collars (n = 18). We observed that the larger, inhalable air particulates carried the bulk (\u3e92%) of HFRs. HFRs detected included those removed from commerce (i.e., polybrominated diphenyl ethers (Penta-BDEs: BDE-47, -85, -100, -99, and -153)), their replacements; e.g., 2-ethylhexyl 2,3,4,5-tetrabromobenzoate (TBB or EH-TBB); bis(2-ethylhexyl) 3,4,5,6-tetrabromophthalate (TBPH or BEH-TEBP) and long-produced chlorinated organophosphate-FRs (ClOPFRs): tris(2-chloroethyl) phosphate (TCEP), tris(1-chloro-2-propyl) phosphate (TCPP or TCIPP), and tris(1,3-dichloro-2-propyl) phosphate (TDCPP or TDCIPP). Our findings suggest estimates relying on a single exposure route, i.e., alveolar gas exchange, may not accurately estimate HFR internal dosage, as they ignore contributions from larger inhalable particulates that enter the digestive tract. Consideration of the fate and bioavailability of these larger particulates resulted in higher dosage estimates for HFRs with log K-oa \u3c 12 (i.e., Penta-BDEs and ClOPFRs) and lower estimates for those with log Koa \u3e 12 (i.e., TBB and TBPH) compared to the alveolar route exposure alone. Of those HFRs examined, the most significant effect was the lower estimate by 41% for TBPH. The bulk of TBPH uptake from inhaled particles was estimated to be through the digestive tract, with lower bioavailability. We compared inhalation exposure estimates to chronic oral reference doses (RfDs) established by several regulatory agencies. The U.S. Environmental Protection Agency (EPA) RfD levels for several HFRs are considered outdated; however, BDE-99 levels exceeded those suggested by the Dutch National Institute for Public Health and the Environment (RIVM) by up to 26 times. These findings indicate that contributions and bioavailability of respirable and inhalable airborne particulates should both be considered in future risk assessments