Extensive aerosol optical properties and aerosol mass related measurements during TRAMP/TexAQS 2006 – Implications for PM compliance and planning

Extensive aerosol optical properties, particle size distributions, and Aerodyne quadrupole aerosol mass spectrometer measurements collected during TRAMP/TexAQS 2006 were examined in light of collocated meteorological and chemical measurements. Much of the evident variability in the observed aerosol-related air quality is due to changing synoptic meteorological situations that direct emissions from various sources to the TRAMP site near the center of the Houston-Galveston-Brazoria (HGB) metropolitan area. In this study, five distinct long-term periods have been identified. During each of these periods, observed aerosol properties have implications that are of interest to environmental quality management agencies. During three of the periods, long range transport (LRT), both intra-continental and intercontinental, appears to have played an important role in producing the observed aerosol. During late August 2006, southerly winds brought super-micron Saharan dust and sea salt to the HGB area, adding mass to fine particulate matter (PM_2.5) measurements, but apparently not affecting secondary particle growth or gas-phase air pollution. A second type of LRT was associated with northerly winds in early September 2006 and with increased ozone and sub-micron particulate matter in the HGB area. Later in the study, LRT of emissions from wildfires appeared to increase the abundance of absorbing aerosols (and carbon monoxide and other chemical tracers) in the HGB area. However, the greatest impacts on Houston PM_2.5 air quality are caused by periods with low-wind-speed sea breeze circulation or winds that directly transport pollutants from major industrial areas, i.e., the Houston Ship Channel, into the city center.     

Application of a novel open-source program for measuring the effects of toxicants on the swimming behavior of large groups of unmarked fish

The aim of this study was to demonstrate a novel method for measuring the effects of toxicants on the behavior of groups of unmarked fish. Ctrax is an open source Python-based machine vision program that was originally designed to track fruit flies (Drosophila). The effects of the fish anaesthetic quinaldine sulfate on the behavior of groups of 10 unmarked Arabian killifish (Aphanias dispar) in a small arena were measured. Ctrax was able to identify and track the X-Y coordinates of the individual fish over 1 min recording periods. The data was analyzed using specifically written Matlab (The Mathworks™) toolboxes and the effects of quinaldine sulfate on absolute swimming velocity, forward swimming velocity, rate of change in orientation and distance to wall were calculated. Additionally the effects of quinaldine sulfate on path tortuosity were also measured. Ctrax has significant benefits over other available technologies for tracking the 2-dimensional coordinates of fish. In particular the software is open source and thus freely available, it is accurate, requires only simple easily available equipment and able to track potentially large groups of fish (possibly >50) while maintaining their individual identities.     

Development and application of long-term sublethal whole sediment tests with Arenicola marina and Corophium volutator using Ivermectin as the test compound

Short-term whole sediment tests using the amphipod Corophium volutator and the polychaete Arenicola marina are now routinely used in Europe to assess the acute toxicity of marine sediments. However, there is still a need to develop longer-term assays which measure effects on sublethal endpoints that are more relevant to predicting impacts at the population level. The effect of increasing exposure times and measuring additional endpoints such as growth, on the sensitivity of these assays was investigated. The test compound used was the chemotherapeutant Ivermectin (IVM), used in aquaculture to treat sea lice infestations. IVM was found to be acutely toxic to both test organisms. Extending the lugworm test to 100 days increased sensitivity of survival by a factor of three; a significant reduction in casting rate was observed at concentrations an order of magnitude lower. This assay shows potential for detecting the sublethal effects of low concentrations of sediment contaminants. Increasing the exposure time did not seem to affect the sensitivity of the amphipod, but further method development is required.     

The Effect of Hydroxyl Radical Generation on Free-Radical Activation of TMP Fibers

The purpose of this work was to study the mechanisms involved in free radical activation of thermal mechanical pulp (TMP) fibers with the ultimate goal of developing methods for bonding wood fiber without the use of traditional adhesives. The generation of hydroxyl radicals in a mediated Fenton system was studied using electron spin resonance (ESR) spin-trapping techniques and indirectly through chemiluminescence measurement. The activation of TMP fibers was also evaluated by ESR measurement of free phenoxy radical generation on solid fibers. The results indicate that low molecular weight chelators can improve Fenton reactions, thus in turn stimulating the free radical activation of TMP fibers. However, it was also shown that excessive and prolonged free radical treatment may cause the destruction of fiber phenoxy radicals. In conclusion, this study demonstrates the potential for application, but also the complexity of free radical chemistry in biological materials, especially with regard to the chelation of transition metals and the interaction between free radicals.     

Operating characteristics of a fabric filter on a peaking/cycling boiler without auxiliary preheat or reheat

A fabric filter has been on-line for one year on a coal-fired boiler that is primarily a peaking unit within the power schedule. For the first six months, Eastern Kentucky coal with 2.5% sulfur was the fuel source for 30% of the time, with low-sulfur Montana coal constituting the remaining fuel during the operation period. Bag life has been excellent with no bag failures reported to date, and the pressure drops have been low. There has never been an auxilliary heat source to preheat the fabric filter for start-up, nor to reheat the fabric filter when operating at reduced load with associated low back-end temperatures. Conclusions are that the filter cake formed does protect the bags from blinding at low load conditions, and a special acid-resistant finish applied to the glass fibers protects the bags when high-sulfur coal is burned at low temperatures. Overall, this installation provides an excellent data base for cycling service and high-sulfur coal usage with a fabric filter.     

Empirical and theoretical evidence concerning the response of the earth's ice and snow cover to a global temperature increase

As a guide to the possible effects of a CO₂-induced warming on the cryosphere, we review the effects of three warm periods in the past, and out theoretical understanding of fluctuations in mountain glaciers, the Greenland and Antarctic ice sheets, ground ice, sea ice and seasonal snow cover. Between 1890 and 1940 A.D. the glaciated area in Switzerland was reduced by over 25%. In the Hypsithermal, at about 6000 BP, ground ice in Eurasia retreated northward by several hundred kilometres. In the interglacial Stage 5e, at about 120 000 BP, global sea-level rose by over 6 m. Fluctuations of mountain glaciers depend on mesoscale “weather” and on their mechanical response to it. Any melting of the Greenland ice sheet is likely to be slow in human terms. The West Antarctic ice sheet (its base below sea-level) is susceptible to an ungrounding, and such an event may have been the cause of the sea-level rise above. The East Antarctic ice sheet is susceptible to mechanical “surges”, which might be triggered by a warming at its margin. Both an ungrounding and a surge might occupy less than 100 yr, and are potetially the most important ice changes in human terms. Modelling studies suggest that a 5°C warming would remove the Arctic pack ice in summer, and this may be the most significant effect for further climatic change.     

Safety Recommendations — The engine that drives change

The National Transportation Safety Board (NTSB) considers the recommendations it makes to prevent accidents and improve the safety of the United States transportation system to be its most important product.In its 25-year history the NTSB has made almost 9,000 safety recommendations covering needed improvements in all the modes of transportation to more than 1,250 recipients. These recommendations are made to anyone the NTSB believes can make the change that is necessary to improve safety. Recommendations have been directed to federal, State and local government agencies, private transportation companies, labor unions, trade associations and others.Overall, more than 80 percent of the NTSB's safety recommendations have been accepted by the recipients and the changes called for have been implemented. This has had a very significant positive impact on the safety of the US transportation system. The NTSB is very proud of this record. The changes that have taken place as a result of the NTSB's recommendations have saved thousands of lives and prevented many accidents.How has the NTSB achieved such a good record? The basic foundation and most important reason for this achievement is the NTSB's independence. This independence lends the NTSB credibility. Recipients of the NTSB's recommendations are more willing to carefully and seriously consider taking the action recommended. The second essential reason for the NTSB's credibility is the highly competent, technical qualifications of its investigators and the thoroughness of its investigations and studies. The NTSB also is very careful and prudent in making its recommendations. Each proposed recommendation is carefully evaluated to make sure it is practical, feasible and capable of being implemented. The credibility of the NTSB has grown over the years, and along with that has come an increase in the acceptance rate of the recommendations.This paper will describe the NTSB's safety recommendation program, how it achieves improved safety, and its important elements, such as the Most Wanted Safety Recommendation Program and the Safety Recommendation Information System.     

Comparisons of pastoralists perceptions about rangeland resource utilisation in the Middle Awash Valley of Ethiopia

Pastoralism is the most dominant land use form in the arid rangelands of Sub-Saharan Africa, but this rangeland-based lifestyle is under threat. As a consequence a study was conducted in the Middle Awash Valley of Ethiopia with the main objectives of assessing and comparing the broad perceptions of two pastoral groups (the Oromo ethnic group living in Kereyu-Fantale and the Afar ethnic group living in Awash-Fantale) on the usage of the existing rangeland resources, and their views on constraints and possible solutions. Data were collected from 90 Oromo and 55 Afar households. Despite the difference in ethnicity both of these groups share common problems. They derive their main income from the sale of animals and animal products, but with the difference that milk products rank first in the case of the Afar and last in the case of the Oromo. Both pastoral groups depend heavily on native grasses for animal feed and to a lesser extent on woody plants as a source of browse. The majority of respondents were of the opinion that the condition of the rangelands is poor, mainly due to overgrazing, droughts and increases in the human population. Availability of water is also regarded as a problem, mainly by the Oromo. Migration is the first measure taken to solve shortages of livestock feed, but many of the pastoralists replied that migration is an undesirable practise which is mostly done out of necessity. Because of the limited resources most respondents of both groups still prefer communal land tenure where resources are shared. It is concluded that the problems facing the pastoralists in the Middle Awash Valley have been created over many years and the solutions will also require time. With the current approach of the communal grazing systems, sustainable utilisation of the rangeland ecosystem is not possible. Solutions to the poor condition of the existing rangelands will require a definite commitment and full participation not only of the pastoralists, but also of government and non-governmental organisations that are directly or indirectly involved in rangeland resources utilisation, management, conservation and other related activities.     

Monitoring of iodinated X-ray contrast media in surface water

A monitoring programme was carried out in order to determine iodinated X-ray contrast media (ICM) in the River Danube and to investigate the raw water quality for drinking water production at Langenau waterworks. The study revealed that the maximum concentrations of ICM (over 500 ng l(-1) for diatrizoic acid and iopamidol) were found in 2h-composite samples taken from the downstream of the Ulm/Neu-Ulm metropolitan area. By means of a concentration profile over one month the highest ICM concentrations were observed on weekdays. The extended data evaluation with principal component analysis shows that the upstream and downstream samples had different pattern of variations in ICM concentration and also demonstrates a clear change in ICM composition by the discharge of municipal wastewater. In addition to load profiles of ICM, time-dependent plots of principal component 1 exhibited peaks, indicating a short-term discharge of ICM between the two sampling sites. In conclusion, a point source for ICM contamination between the sampling sites in Ulm upstream and Leipheim downstream seems to be the reasonable explanation for peak ICM concentrations. Due to the observed high variations of ICM concentrations in river, the evaluation of natural waters by means of a single analysis is not representative.     

Lattice-based methods for regression and density estimation on complicated multidimensional regions

Environmental and Ecological Statistics - This paper illustrates the use of diffusion kernels to estimate smooth density and regression functions defined on highly complex domains. We generalize...