Comparison of stack measurement data from R&D facilities to regulatory criteria: A case study from PNNL

Chemical emissions from research and development (R&D) activities are difficult to estimate because of the large number of chemicals used and the potential for continual changes in processes. In this case study, stack measurements taken from R&D facilities at Pacific Northwest National Laboratory (PNNL) were examined, including extreme worst-case emissions estimates and alternate analyses using a Monte Carlo method that takes into account the full distribution of sampling results. The objective of this study was to develop techniques to estimate emissions from stack measurement data that take into account a high degree of variability in the actual emissions. The results from these analyses were then compared to emissions estimated from chemical inventories. Results showed that downwind ambient air concentrations calculated from the stack measurement data were below acceptable source impact levels (ASILs) for almost all compounds, even under extreme worst-case analyses. However, for compounds with averaging periods of a year, the unrealistic but simplifying extreme worst-case analysis often resulted in calculated emissions that were above the lower level regulatory criteria used to determine modeling requirements or to define trivial releases. Compounds with 24-hr averaging periods were nearly all several orders of magnitude below all, including the trivial release, criteria. The alternate analysis supplied a more realistic basis of comparison and an ability to explore effects under different operational modes.

Implications:

Air emissions from research operations are difficult to estimate because of the changing nature of research processes and the small quantity and wide variety of chemicals used. Stack measurements can be used to verify compliance with applicable regulatory criteria. This study shows that while extreme worst-case assumptions can be used for a relatively simple initial comparison, methods that take into account the full range of measurement data are needed to provide a more realistic estimate of emissions for comparison to regulatory criteria, particularly those criteria that define trivial levels of environmental concern.     

The impact of visual information on perceptions of water resource problems and management alternatives

To assess changes in human understanding and decision making, the paper examines (1) the influence of visual information on perceptions about groundwater management in Phoenix, Arizona and (2) the correlates and dimensions underlying people's views about water scarcity and mitigation strategies. While perceptions entrenched in ideologies are difficult to change, different types of information (three-dimensional versus two-dimensional) have distinct impacts on the perceived magnitude of problems compared to judgements about their causes and solutions. Overall, visual information may be especially useful for developing a shared understanding of problems and a collective vision for management alternatives. Additional implications of this study for fostering environmental awareness, policy support, and collaborative decision making are also discussed.     

Ultrastructure of the ovary and oogenesis in the jellyfish Linuche unguiculata and Stomolophus meleagris,with a review of ovarian structure in the Scyphozoa

Ovarian structure and oogenesis has been examined in six scyphozoan species including the semaeostome Diplumularis antarctica Maas, 1908 (collected in 1987 in McMurdo Sound, Antarctic), the rhizostomes Cassiopea xamachana Bigelow, 1892 (collected in Belize in 1988), and Stomolophus meleagris L. Agassiz, 1862 (collected in Ft. Pierce Inlet in 1988), and the coronates Periphylla periphylla (Peron and Lesueur, 1810), Nausithoe atlantica Broch, 1914 (both collected in the Bahamas in 1988), and Linuche unguiculata (Schwartz, 1788) (collected in Nassau Harbor, Bahama Islands in 1989). Based on these findings and information on five other scyphozoan species from additional literature sources, at least two fundamentally different types of ovaries exist in the Scyphozoa. In semaeosotome and rhizostome species, oocytes develop in close association with specialized gastrodermal cells called trophocytes which may serve a nutritive function. However, coronate species lack trophocytes and oocytes develop freely in the mesoglea. The ovaries of S. meleagris and L. unguiculata are used as models to represent the ultrastructural events occurring during oogenesis in species having trophocytes and those lacking them, respectively. In both L. unguiculata and S. meleagris, the ovaries arise as evaginations of the gastrodermis in the floor of interradial pouches. Germ cells appear to originate from endodermally-derived gastrodermal cells and migrate into the mesoglea prior to vitellogenesis. In L. unguiculata, the oocytes develop freely within the mesoglea throughout vitellogenesis, while in S. meleagris each oocyte maintains contact with specialized gastrodermal cells called trophocytes. In the vitellogenic oocytes of both species, numerous invaginations of the oolemma result in the formation of intraooplasmic channels throughout the ooplasm. These channels are intimately associated with cisternae of rough endoplasmic reticulum and may play some role in yolk precursor uptake by substantially increasing the surface area of the oocyte. Vitellogenesis is similar in both species and involves the autosynthetic activity of the Golge complex and rough endoplasmic reticulum, and the heterosynthetic incorporation of yolk precursors through receptor-mediated endocytosis. However, in the oocytes of S. meleagris, the trophocytes probably play a role in the transfer of nutrients from the gastrovascular cavity to the oocyte. The present study suggests that scyphozoans were among the first metazoans to develop ovarian accessory cells during their reproductive evolution. The trophocyte-oocyte association observed in some scyphozoans is similar to but structurally less complex than the trophonema-oocyte association described from anthozoans. Scyphozoan ovarian morphology helps support the view that the Scyphozoa share a closer phylogenetic relationship with the Anthozoa than with the Hydrozoa.     

Effects of Rock Climbing on Populations of Presettlement Eastern White Cedar (Thuja occidentalis) on Cliffs of the Niagara Escarpment, Canada

Cliffs of the Niagara Escarpment support a self-sustaining presettlement forest of eastern white cedar (  Thuja occidentalis L.) in which some trees are over 1000 years old. Many of the cliffs are also popular locations for recreational rock climbing. Our study employed a stratified random sampling design to assess the impact of rock climbing on populations of cliff-face and cliff-edge trees. Tree density and age structure were compared between four climbed and three unclimbed sites in the vicinity of Milton, Ontario. Signs of physical damage were also recorded for the trees sampled at each site. The results showed that living tree density on the cliff face was lower in climbed areas. The age structures of these forests showed that the numbers of older and younger age classes have been reduced on climbed cliff faces compared with unclimbed areas. A high percentage of trees on climbed cliff faces showed evidence of damage by humans. These trends were not as apparent on cliff edges where other disturbances have affected age structure. We recommend that cliff faces be explored for the presence of presettlement forest and that recreation managers of lands with exposed cliff faces incorporate rock climbing considerations into their management plans. Monitoring programs would help track levels of disturbance. Education of the climbing community would be the most effective long-term solution to limiting disturbance in sensitive areas.     

Feeding and nutritional ecology of the sea urchin strongylocentrotus drobachiensis in Maine,USA

The sea urchin strongylocentrotus drobachiensis exhibited a high degree of food selectivity, whether foods were presented singly or in combination. Foods ranked from most to least preferred were, in summer, Laminaria longicruris, Chondrus crispus, Corallina officinalis, Ascophyllum nodosum, and Agarum cribrosum, whereas in winter A. nodosum and A. cribrosum exchanged ranks. Food preference was not correlated with caloric content but, because of higher feeding rates on preferred foods, caloric intake was positively correlated with preference. Similarly, food absorption rankings were not correlated with food preference, with the exception of gravimetric efficiencies in winter. However, the absorption of L. longicruris, the most preferred alga, was highest in all measurements. Growth and reproductive development of S. drobachiensis on single species diets were positively correlated with food preference. Highest values occurred with animals fed L. longicruris. Urchins transferred from non-preferred to preferred diets showed increased somatic and reproductive growth compared to control animals on the original, non-preferred diets. Conversely, when transferred from preferred to non-preferred diets, urchins showed reduced growth compared to controls. No combination diet tested supported significantly better gonadal growth than L. longicruris: 25% C. crispus supported slightly better somatic growth than L. longicruris alone. These data support the view that S. drobachiensis has evolved a feeding strategy resulting in the maximization of growth and reproduction.     

Spatial and temporal trends of precipitation chemistry in the United States, 1985-2002

A Seasonal Kendall Trend (SKT) test was applied to precipitation-weighted concentration data from 164 National Atmospheric Deposition Program National Trends Network (NADP/NTN) sites operational from 1985 to 2002. Analyses were performed on concentrations of ammonium, sulfate, nitrate, dissolved inorganic nitrogen (DIN, sum of nitrogen from nitrate and ammonium), and earth crustal cations (ECC, sum of calcium, magnesium, and potassium). Over the 18-year period, statistically significant (p< or =0.10) increases in ammonium concentrations occurred at 93 sites (58%), while just three sites had statistically significant ammonium decreases. Central and northern Midwestern states had the largest ammonium increases. The generally higher ammonium concentrations were accompanied by significant sulfate decreases (139 sites, 85%), and only one significant increase which occurred in Texas. In the west central United States there were significant nitrate increases (45 sites, 27%), while in the northeastern United States there were significant decreases (25 sites, 15%). Significant DIN decreases were observed in the northeastern United States (11 sites, 7%); elsewhere there were significant increases at 75 sites (46%). ECC decreased significantly at 65 sites (40%), predominantly in the central and southern United States, and increased at 11 sites (7%). The concentrations of sulfate, nitrate, and ammonium in precipitation have changed markedly over the time period studied. Such trends indicate changes in the mix of gases and particles scavenged by precipitation, possibly reflecting changes in emissions, atmospheric chemical transformations, and weather patterns.     

Surfactant-assisted UV-photolysis of nitroarenes

Photochemical transformations (lambda-254 nm) of 2,4-dinitrotoluene (2,4-DNT) in aqueous solutions containing the cationic surfactant cetyltrimethylammonium (CTA) and the anionic nucleophile borohydride (BH4-) were investigated. The overall decay rate was enhanced at CTA concentrations above the critical micelle concentration (cmc) when stoichiometric excess BH4- was present in solution. A kinetic model that separates the overall reaction rate into micellar and aqueous pseudo-phase components indicates transformation in micelles is 17 times faster that in the homogeneous water phase under those conditions investigated. Intermediate products were identified by comparing the HPLC retention times and ultraviolet-visible absorption spectra of product peaks to those of analytical standards. 2-Methyl-5-nitroaniline, 4-nitrotoluene, 2-nitrotoluene, 4-methyl-3-nitroaniline, 2,4-diaminotoluene, o-toluidine, 1,3-dinitrobenzene, 3-nitroaniline, p-cresol, and 2,4-diaminophenol were identified as photo-transformation intermediates or products.     

Autotoxic effects of essential oils on photosynthesis in parsley, parsnip, and rough lemon

Summary. Many plant species contain essential oils with allelochemical properties, yet the extent to which these same chemicals can be autotoxic is unclear. In this study, we tested the toxicity of several essential oil components to three species that produce them—Pastinaca sativa and Petroselinum crispum (Apiaceae), and Citrus jambhiri (Rutaceae). The effects of exogenous application of small amounts of essential oil components to the surface of foliage, followed by a pinprick to allow entry into the leaf, were monitored by chlorophyll fluorescence imaging. Rapid and spatially extensive declines in photosynthetic capacity were detected within 200 s. The most toxic constituents were monoterpenes. Two sesquiterpenes, caryophyllene and farnesene, and the phenylpropanoid myristicin, by comparison, were not toxic. Autotoxicity of endogenous essential oil was investigated by slicing through containment structures (glands or tubes); significant toxicity, manifested by reduced photosynthetic activity, was observed in all three species but was most pronounced in P. sativa and P. crispum, both of which possess oil tubes.