Summer Transport Patterns Affecting the Mohave Power Project Emissions

The Mohave Power Project (MPP) is an isolated 1580-MW coal-fired electric generating plant located in Laughlin, NV. Laughlin is a small desert gambling town situated in the lower Colorado River Valley near the junction of three states: Nevada, California, and Arizona. The location of the MPP is approximately 115 km southwest of the western end of the Grand Canyon National Park and about 240 km southwest from the Grand Canyon Village. This paper describes the summer transport patterns of the MPP emittants using illustrated examples from the Project MOHAVE (Measurements of Haze and Visual Effects) 1992 summer intensive study. The intensive study lasted 50 days from mid-July through August and encompassed the major meteorological patterns associated with southwestern U.S. summer meteorology. The MPP emittants were transported toward the Grand Canyon (north to the northeast) during more than 80% of the total hours. Airflow was from the south most of the time due to a combination of the semi-permanent thermal low, differential heating between the Gulf of California and lower Colorado River Valley, and upslope heating of the southern and western slopes of the nearby Colorado Plateau.     

What do we really know about the impacts of one of the 100 worst invaders in Europe? A reality check

Invasive species are one of the greatest threats to biodiversity worldwide, and to successfully manage their introductions is a major challenge for society. Knowledge on the impacts of an invasive species is essential for motivating decision makers and optimally allocating management resources. We use a prominent invasive fish species, the round goby (Neogobius melanostomus) to objectively quantify the state of scientific knowledge on its impacts. Focusing on how native fish species are affected by round goby invasions, we analyzed 113 peer-reviewed papers and found that impacts are highly ecosystem and time scale dependent. We discovered round goby impacts to be profound, but surprisingly complex. Even if identical native species were affected, the impacts remained less comparable across ecosystems than expected. Acknowledging the breadth but also limitations in scientific knowledge on round goby impacts would greatly improve scientists’ ability to conduct further research and inform management measures.

Electronic supplementary material

The online version of this article (doi:10.1007/s13280-015-0718-9) contains supplementary material, which is available to authorized users.     

“They give you lots of information,but ignore what it's really about”: residents' experiences with the planned introduction of a new high-voltage power line

Cases of strong local opposition to the planned introduction of new high-voltage power lines (HVPLs) have been documented in the past. During and after the planning process for a new HVPL, local residents will be informed about the siting process and its outcomes. Although it has been suggested in the literature that this communication plays an important role in residents' responses to a new HVPL, it has been rarely empirically studied. In this qualitative study, we conducted in-depth interviews with 15 residents about their experiences with the planned introduction of a new HVPL near their homes. Thematic analysis revealed that residents' experiences were centred around negative expectations of living near the new HVPL and perceived injustice of the planning process and its outcomes. Residents' perception that communication was not tailored to their information needs played a significant role in these negative experiences. Suggestions for improving communication will be discussed.     

Remobilization of trace elements by forest fire in Patagonia,Chile

Temporal changes in the amounts of trace elements (As, Co, Cu, Mn, Ni, Pb, and Zn) and their correlations with temporal changes in charcoal abundance in age-dated sediments collected from Lake Thompson in Patagonia, Chile, attest to the substantial pyrogenic remobilization of contaminants that occurred in Patagonia during the mid-1900s. This remobilization was concurrent with the extensive slash and burn period in the region during that period. The changes in concentrations of Co, Cu, and Ni in relation to charcoal abundance in the lacustrine sediments over time were small compared to those of As, Mn, Pb, and Zn. However, the relatively low enrichment factors of all those trace elements, normalized to Fe, indicate that they were predominantly derived from local, natural sources impacted by fires rather than industrial sources. The primarily local source of Pb in the sediments was corroborated by the temporal consistency of its isotopic ratios (²⁰⁶Pb/²⁰⁷Pb:²⁰⁸Pb/²⁰⁶Pb), which were similar to previously reported values for natural lead in Central and Southern Chile. However, the pyrogenic remobilization of both natural and industrial trace elements by forest fires in Chile and elsewhere is expected to rise as a consequence of climate change, which is projected to increase both the frequency and intensity of forest fires on a global scale.     

Microplastics affect assimilation efficiency in the freshwater amphipod <Emphasis Type="Italic">Gammarus fossarum</Emphasis>

An important issue in assessing microplastics is whether this newly emerging type of pollution affects freshwater invertebrates. This study was designed to examine the interactions between the amphipod Gammarus fossarum and two types of microplastics. To determine the ingestion and egestion of polyamide (PA) fibres (500 × 20 μm), amphipods were exposed to four concentrations (100, 540, 2680, 13,380 PA fibres cm^?2 base area of glass beakers) and four exposure times (0.5, 2, 8, 32 h) as well as four post-exposure times (1, 2, 4, 16 h). We demonstrate a positive correlation between concentration and ingestion of PA fibres. Fibres were found in the gut after 0.5 h of exposure. Egestion was rapid and the digestive tract was empty 16 h after exposure ended. To investigate whether polystyrene (PS) beads (1.6 μm) can be taken up in the epithelial cells of the gut and the midgut glands, four concentrations (500, 2500, 12,500, 60,000 PS beads mL^?1) were tested. Cryosections exhibited fluorescent PS beads only within the gut lumen. In a 28-day feeding experiment with both, fibres and beads, we studied the amphipod’s feeding rate, assimilation efficiency and wet weight change. The exposure to PA fibres (2680 PA fibres cm^?2 base area of glass beakers) significantly reduced the assimilation efficiency of the animals. While both tested polymer types are ingested and egested, PA fibres can impair the health and ecological functions of freshwater amphipods under continuous exposure.     

Effect of water composition on the photocatalytic removal of pesticides with different TiO2 catalysts

The objective of this work is double—firstly to explore the photocatalytic efficiency of five different commercial TiO₂ catalysts in the photodegradation of a mixture of pesticides classified by the EU as priority pollutants and secondly to analyze the correlation between their physicochemical properties and the inhibition of the studied photocatalytic process when natural water was employed. Photocatalytic efficiencies when ultrapure water was used seem to point out that surface area was not a prerequisite for the photodegradation of the selected mixture of pesticides. On the other hand, significant differences in total organic carbon (TOC) conversions were obtained with the two studied water compositions. On one side, Evonik materials appear to be mostly inhibited when natural water was employed, whereas on the other, it should be remarked that anatase Sigma-Aldrich (SA) and, particularly, Hombikat UV100 (HBK) materials presented a very limited photo-efficiency inhibition or even a higher initial rate of TOC removal when a natural water matrix was used, probably due to their specific surface properties (PZC, S _BET). Therefore, heterogeneous photocatalysis has proved to be a promising technology for the degradation of the selected mixture of pesticides where the final photo-efficiency of the five commercial titania catalysts studied here responds to a complex balance between its surface and structural properties.     

Bacterial Cellulose from Simple and Low Cost Production Media by Gluconacetobacter xylinus

Bacterial cellulose pellicles were produced by Gluconacetobacter xylinus using non conventional low-cost carbon sources, such as glycerol remaining from biodiesel production and grape bagasse, a residue of wine production. The carbon sources assayed showed their suitability for microbial cellulose production, with relatively high production values such as 10.0 g/l for the culture medium with glycerol from biodiesel as carbon source and corn steep liquor as nitrogen source; and 8.0 g/l for the culture medium containing grape bagasse and corn steep liquor. Glucose, commercial glycerol and cane molasses were also assayed as carbon sources for comparison. The bacterial celluloses produced were characterized by means of scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy and thermogravimetric analysis. Morphological analysis showed that bacterial cellulose microfibrils produced from the non-conventional media used were several micrometers long and had rectangular cross-sections with widths and thicknesses in the range of 35–70 and 13–24 nm, respectively. X-ray patterns showed crystallinity levels in the range of 74–79 % (area method), whereas both X-ray patterns and infrared spectroscopy evidenced the presence of peaks characteristic of Cellulose I polymorph. Besides thermal properties were similar to those found for the pellicle obtained from glucose. The study performed showed the suitability of using wine residues or glycerol remaining from increasing biodiesel production as cheap carbon sources for production of bacterial cellulose microfibrils, with similar characteristics as those obtained by use of more expensive carbon sources such as glucose or commercial glycerol. On the other hand, the low cost nitrogen sources used (corn steep liquor or diammonium phosphate) also contributed to the economy of the bioprocess.     

Assessment of irrigation water quality. A proposal of a quality profile

Water quality indices provide a simple and understandable tool for managers on the quality and possible uses for irrigation water, however an individual quality factor alone is not enough to evaluate the irrigation water quality because it could be restrictive and sometime it could give an unfavorable qualification. The aim of this paper was propose a quality profile of irrigation water using the preexisting water quality indices to be applied to arid and semi-arid regions. As a case studied, the water of the Del Molle River (Nogolí, San Luis, Argentina) was researched. Samples were collected during the period October 2005-May 2006. Conductivity, pH, total hardness, sulphate, nitrate, nitrite, alkalinity, chloride, sodium, potassium, TDS, DO and phosphate were analyzed. The irrigation water quality, according to Riverside Norm, belongs to C(2)-S(1) class, according to Wilcox Norm as excellent to good, according to Scott quality factor it is good and according to SAR < 10 and according to RCS it is recommendable. From the obtained data, it can be concluded that the water quality profile was good, so it is useful for normal irrigation agriculture.     

Does the Maryland graduated driver licensing law affect both 16-year-old drivers and those who share the road with them?

PROBLEM: To assess effects of the 1999 Maryland graduated driver licensing (GDL) law on both 16-year-old drivers and other road users. METHOD: Calculation and comparison of crash involvement rates and non-fatal injury rates pre-GDL (1996-1998) and post-GDL (2001-2003) by type of road user, per population, and per licensed driver, with adjustment for trends among 30-59-year-old drivers. RESULTS: Post-GDL, prevalence of licensure decreased 24% among 16-year-olds, and rates of 16-year-old drivers involved in crashes significantly decreased per 16-year-old population (corrected rate ratio (RRc) 0.82; 95% CI (0.71, 0.96)). A significant decrease also was observed for non-fatal injuries per 16-year-old population among 16-year-old drivers involved in crashes (RRc 0.63; 95% CI (0.41, 0.98)). Similarly, decreases, albeit not statistically significant, were observed among their passengers and other vehicle occupants. Per 16-year-old licensed driver, a slight non-significant increase was observed in crash involvement rates; non-fatal injury rates per 16-year-old licensed driver suggest decreased risk (non-significant) among 16-year-old drivers, their passengers, and other vehicle occupants. SUMMARY: Maryland's GDL delayed licensure and reduced crashes and non-fatal injuries among 16-year-old drivers per population. Trends in injuries among other road users involved in crashes with 16-year-old drivers were suggestive of a benefit from GDL, although observed decreases were not significant. Per licensed driver, findings were not significant, but suggested little change in crash involvement and decreased non-fatal injuries. Because one-third fewer 16-year-olds were licensed post-GDL, these results may suggest a selection effect in licensure. IMPACT ON INDUSTRY: Because Maryland had nighttime restrictions for new drivers before 1999, this study suggests other components of GDL are beneficial for drivers and possibly for other road users. States with weak GDL laws should strongly consider revising them.