A framework for evaluating regional-scale numerical photochemical modeling systems

This paper discusses the need for critically evaluating regional-scale (~200–2,000 km) three-dimensional numerical photochemical air quality modeling systems to establish a model’s credibility in simulating the spatio-temporal features embedded in the observations. Because of limitations of currently used approaches for evaluating regional air quality models, a framework for model evaluation is introduced here for determining the suitability of a modeling system for a given application, distinguishing the performance between different models through confidence-testing of model results, guiding model development and analyzing the impacts of regulatory policy options. The framework identifies operational, diagnostic, dynamic, and probabilistic types of model evaluation. Operational evaluation techniques include statistical and graphical analyses aimed at determining whether model estimates are in agreement with the observations in an overall sense. Diagnostic evaluation focuses on process-oriented analyses to determine whether the individual processes and components of the model system are working correctly, both independently and in combination. Dynamic evaluation assesses the ability of the air quality model to simulate changes in air quality stemming from changes in source emissions and/or meteorology, the principal forces that drive the air quality model. Probabilistic evaluation attempts to assess the confidence that can be placed in model predictions using techniques such as ensemble modeling and Bayesian model averaging. The advantages of these types of model evaluation approaches are discussed in this paper.     

Macroinvertebrate and fish populations in a restored impounded salt marsh 21 years after the reestablishment of tidal flooding

During the last two decades, the State of Connecticut has restored tidal flow to many impounded salt marshes. One of the first of these and the one most extensively studied is Impoundment One in the Barn Island Wildlife Management Area in Stonington, Connecticut. In 1990, twelve years after the re-establishment of tidal flooding, the density of the marsh snail Melampus bidentatus, the numerically dominant macroinvertebrate of the high marsh, in Impoundment One was about half that in reference marshes below the breached impoundment dike. By 1999 the densities of Melampus above and below the dike were not significantly different, but the shell-free biomass was greater above the dike as a result of the somewhat larger number and size of the snails there. Twenty-one years after the renewal of tidal flooding, three marsh macroinvertebrates (the amphipods Orchestia grillus and Uhlorchestia spartinophila and the mussel Geukensia demissa) were significantly less abundant in the previously impounded marsh than in the reference marshes, whereas another amphipod (Gammarus palustris) was more abundant above the breached dike where conditions appeared to be somewhat wetter. In 1991 the fish assemblage in a mosquito-control ditch in Impoundment One was similar to that in a ditch below the breached dike; however, the common mummichog Fundulus heteroclitus appeared to be less abundant in the restoring marsh. By 1999 the number of mummichogs caught in ditches was significantly greater in Impoundment One than in the reference marsh, but the numbers of mummichogs trapped along the tidal creek were comparable above and below the dike. The results obtained in this study and those of other restoring marshes at Barn Island indicate the full recovery of certain animal populations following the reintroduction of tidal flow to impounded marshes may require up to two or more decades. Furthermore, not only do different species recover at different rates on a single marsh, but the time required for the recovery of a particular species may vary widely from marsh to marsh, often independently of other species.     

Correlations between Human Collecting and Intertidal Mollusc Populations on Rocky Shores

We tested whether the population structures of intertidal molluscs varied with the activity of human collectors in northern Port Phillip Bay, Victora, Australia. We examined eight sites, two of which had been protected for around 70 years by the area being used as a rifle range with the other six being visited frequently by human. The shores were examined in two different years, and in 1991 we counted humans and recorded their activities. At heavily visited shores, almost half of the people seen were simply walking, while 25% were actively collecting, despite regulations prohibiting the collection of intertidal gastritis. The remaining people were fishing or skydiving. At the protected shores, we observed only one collector and a handful of walkers over more than 20 observation periods, including weekdays, normal weekends, and holiday weekends. In 1989 and 1991, we compared size distributions of seven intertidal species between sites in the two categories. Four mollify species are taken for food and bait; the remaining three served as “controls”. The size distributions and abundance of noncarbonated species (alicized napalm, Leaderless viola, and emization ebonies) did not differ between visited and protected sites in either year, although most species did vary between individual sites. In contrast, three of the four collected species, alicize trampoliners, Austrocochlea constricta, and Nerita atramentosa, were significantly larger at the protected sites, and N. atramentosa was markedly less abundant at heavily visited sites. The fourth collected species, Turbo undulatus, has a distribution extending into the subtidal zone, and it is possible that intertidal populations ate replenished from deeper water. The changes in mean size of molluscs are well within the range reported from South America and South Africa under subsistence fishing, and they demonstrate that at least close to major urban centers, human recreational activities can have substantial effects in developed countries.     

Exposure to four chemical UV filters through contaminated sediment: impact on survival,hatching success,cardiac frequency,and aerobic metabolic scope in embryo-larval stage of zebrafish

Environmental Science and Pollution Research - UV filters are widely used in many pharmaceutical and personal care products such as sunscreen and cosmetics to protect from UV irradiation. Due to...     

Patterns of substance use among Hurricane Katrina evacuees in Houston,Texas

This paper focuses on changing patterns of substance use among low income, African American drug users evacuated from New Orleans, Louisiana, during Hurricane Katrina of August 2005. It examines the relationship between increases and decreases in alcohol and tobacco (AT) use and illicit drug (ID) use after Katrina and pre‐disaster and within‐disaster factors. Data from structured interviews with 200 Katrina evacuees currently living in Houston were collected 8–14 months after the disaster. Multivariate analysis revealed that rises in AT use were positively associated with education. Females and younger evacuees were more likely to have increased AT use. ID use increase was positively associated with resource loss and leaving the city before Katrina. Decreases in AT and ID use were found to be associated with disaster‐related exposure. The paper discusses the specific consequences of disasters on disadvantaged minority substance users and the importance of developing public health disaster policies that target this population.     

The potential of animal manure management pathways toward a circular economy: a bibliometric analysis

Environmental Science and Pollution Research - Improper disposal of animal waste is responsible for several environmental problems, causing eutrophication of lakes and rivers, nutrient overload in...