PREDICTING FECAL COLIFORM BACTERIA LEVELS IN THE CHARLES RIVER,MASSACHUSETTS, USA1

In Massachusetts, the Charles River Watershed Association conducts a regular water quality monitoring and public notification program in the Charles River Basin during the recreational season to inform users of the river's health. This program has relied on laboratory analyses of river samples for fecal coliform bacteria levels, however, results are not available until at least 24 hours after sampling. To avoid the need for laboratory analyses, ordinary least squares (OLS) and logistic regression models were developed to predict fecal coliform bacteria concentrations and the probabilities of exceeding the Massachusetts secondary contact recreation standard for bacteria based on meteorological conditions and streamflow. The OLS models resulted in adjusted R²s ranging from 50 to 60 percent. An uncertainty analysis reveals that of the total variability of fecal coliform bacteria concentrations, 45 percent is explained by the OLS regression model, 15 percent is explained by both measurement and space sampling error, and 40 percent is explained by time sampling error. Higher accuracy in future bacteria forecasting models would likely result from reductions in laboratory measurement errors and improved sampling designs.     

Cathode ray tube glass recycling: an example of clean technology.

In this study the use of 'cleaned' end of life (EOL) cathode ray tube (CRT) glass as a raw material in ceramic glazes is described. At present, the recycling and industrial utilization of CRT, a glass material from TV and computer sets, is a subject of intense research with particular regard to the so-called open-loop recycling, namely cycles different from that of the origin. However, the use of CRT glass as a secondary raw material is strictly related to the demand of high-quality raw material. The good preliminary results reached by introducing clean TV and PC monitor panel and cone glass into ceramic glaze formulations pushed research toward the setting-up of a base glaze that is exploitable for the production of pigmented, silk-screened and flame-hardened glazes (products used industrially for coating floor tiles). The aesthetic and chemical characterization of the tiles glazed by this product showed an extremely similar behaviour to originals that did not contain CRT glass. The good technical results achieved have been supported by the life cycle assessment analysis, which has demonstrated a reduction of the environmental impact of the CRT glass-containing ceramic glaze with respect to the standard one.     

Sex-specific effects of parasites on telomere dynamics in a short-lived passerine—the blue tit

The pollination syndrome concept implies that flowers evolved with particular sets of characteristics, such as colors, shapes, orientations, and rewards, as a means of attracting pollinators. However, these traits may have also evolved to deter unwanted visitors. The North American genus Penstemon exhibits a great floral diversity that is mainly associated with bumblebee and hummingbird pollination. Evolutionary shifts from insect pollination to hummingbird pollination have occurred in Penstemon repeatedly, but some species maintain mixed-pollination systems and intermediate floral traits between bee- and hummingbird-pollination modes. The apparently intermediate floral traits of species with mixed-pollination systems might be potentially acting to deter bumblebee foragers. Then, bird-flower traits might be selected with increased hummingbird visitation over evolutionary time might, resulting in specialization to and the evolution of floral traits present in hummingbird-pollinated species. Here, we modified bee-pollination floral traits in Penstemon gentianoides with a mixed pollination system, to resemble hummingbird-pollination traits, and measured the effects of trait modification on bumblebee foraging behavior and plant female reproductive fitness. Our results showed that reduction in the width of the corolla tube and the absence of the corolla lip negatively affects bumblebee visitation and their efficiency as pollinators, and that the synergistic interaction of both traits enhanced the “anti-bee” effect. We conclude that acquisition of floral traits that resemble those of hummingbird-pollination enables Penstemon plant species to deter bumblebee visits.

     

Organochlorine pollutants in Scots pine needles--biological and site related variation within a forest stand

To study the biological variation in the content of some persistent organic pollutants, viz hexachlorobenzene (HCB), alpha- and gamma-hexachlorocyclohexane (alpha- and gamma-HCH), and 1,1,1-trichloro-2,2-bis-(4-chlorophenyl)-ethane (DDT) were analysed in needles from Scots pine trees growing at an isolated peninsula south of Stockholm, Sweden. The concentration variations of each compound was evaluated by a nested analysis of variance (ANOVA) with sampling site specific compass direction, individual tree, and sampling height as factors. Two pair-wise post hoc tests were used to test significant results from the ANOVA. The hexachlorocyclohexanes showed no significant differences between sampling site, trees or sampling height. DDT concentration was significantly lower at the sampling site with the densest vegetation compared to at least three of the other sampling sites. HCB was significantly lower at the lowest sampling height (0.5 m).     

An experimental and numerical investigation into the impact of dissolution/precipitation mechanisms on CO2 injectivity in the wellbore and far field regions

Carbon dioxide capture and storage (CCS) technology is gaining credibility as the best short to medium term solution for significantly reducing net carbon emissions into the atmosphere. From a capacity point of view, deep saline aquifers offer the greatest potential for CO₂ storage. In this respect, well injectivity is considered a key technical and economical issue. Rock/fluid interactions – dissolution/precipitation of minerals, in particular carbonates – are currently considered as one of the principal reasons for wellbore injectivity changes in aquifers.This research investigated the mechanisms involved in injectivity losses through experimental and theoretical methods. The impact on injectivity of permeability changes occurring at various distances from the wellbore was studied using an idealised CO₂ injection well flow model. A new experimental set-up was used to investigate the effect on dissolution/precipitation mechanisms of the pressure and temperature changes that the fluid is subjected to as it advances from the wellbore.Numerical modelling of the injection wellbore has shown that changes in the petrophysical properties of the reservoir several metres away from the wellbore can still have a significant impact on injectivity. As indicated by the experimental research carried out, pressure and temperature gradients that exist inside the reservoirs may lead to re-precipitation in the far field, however no significant permeability and porosity changes were detected to suggest major losses of injectivity due to these effects.     

Utilization of Industrial Wastes from Mining and Packaging Industries in Wood-Plastic Composites

The manufacturing industry produces a lot of different by-products and waste. In this research, the utilization of different industrial wastes as a part of wood-plastic composites was tested. Limestone waste and carton cutting waste were tested by replacing part of the reinforcing fibers of the composite with these materials. The materials were made with the extrusion process, and they were tested for their mechanical properties, water absorption and thickness swelling. The materials were also viewed with a scanning electron microscope. The results showed that both industrial wastes affected the properties of the composite. Mining waste in the composite improved the moisture properties, impact strength and hardness of the material. Carton cutting waste improved the impact strength remarkably.     

Effects of smelter sulfur dioxide emissions: a spatiotemporal perspective using carbon isotopes in tree rings

We wanted to test the hypothesis that forest exposure to phytotoxic gases indirectly affects their carbon uptake. We estimated that the reduction of photosynthesis may have reached 20 to 30% at a site located 9 km (test site) from the Horne copper smelter in Rouyn-Noranda, which is a point source of SO2. Twenty-one spruce trees older than 100 yr were selected from seven sites at various distances from the smelter to evaluate conditions prior to and during the periods of smelter operation. The carbon isotope results obtained from spruce tree rings at our test site reveal an unprecedented and abrupt shift of +4/1000 after the onset of smelter operations. This large and permanent shift exceeds natural variations in regional pre-smelter series or in the series at a remote control site. All trees up to 116 km downwind from the smelter show delta13C positive shifts following the onset of operations. There is also a clear inverse relationship between the amplitude of the first-order trends and distance from the smelter. Those delta13C trends indicate that trees exposed to high levels of SO2 decrease their level of CO2 uptake through activation of stomatal closure. This is strongly supported by the significant departure of the Rouyn-Noranda trends from those measured for trees from non-industrialized areas of the Northern Hemisphere, or calculated using global atmospheric conditions. Considering the large number of SO2 point sources in North America, our results imply that CO2 uptake by the boreal forest in the vicinity of these sources may be lower than previously thought.     

Curve Number Derivation for Watersheds Draining Two Headwater Streams in Lower Coastal Plain South Carolina,USA

The objective of this study was to assess curve number (CN) values derived for two forested headwater catchments in the Lower Coastal Plain (LCP) of South Carolina using a three‐year period of storm event rainfall and runoff data in comparison with results obtained from CN method calculations. Derived CNs from rainfall/runoff pairs ranged from 46 to 90 for the Upper Debidue Creek (UDC) watershed and from 42 to 89 for the Watershed 80 (WS80). However, runoff generation from storm events was strongly related to water table elevation, where seasonally variable evapotranspirative wet and dry moisture conditions persist. Seasonal water table fluctuation is independent of, but can be compounded by, wet conditions that occur as a result of prior storm events, further complicating flow prediction. Runoff predictions for LCP first‐order watersheds do not compare closely to measured flow under the average moisture condition normally associated with the CN method. In this study, however, results show improvement in flow predictions using CNs adjusted for antecedent runoff conditions and based on water table position. These results indicate that adaptations of CN model parameters are required for reliable flow predictions for these LCP catchments with shallow water tables. Low gradient topography and shallow water table characteristics of LCP watersheds allow for unique hydrologic conditions that must be assessed and managed differently than higher gradient watersheds.