Study on the determination of PCDDs/Fs and HCB in exhaust gas

The subject of this study was to develop a method of simultaneous determination of PCDDs/PCDFs and HCB in exhaust gases from industrial installations. Sampling to determine PCDDs/PCDFs was conducted using the method described in PN-EN 1948-1: 2006, where the sorption material is polyurethane foam (PUF). In order to simultaneously collect PCDDs/PCDFs and HCB and to avoid sorbent bed breakthrough, it was necessary to apply an additional polyurethane sorption layer. Twenty-seven samples of exhaust gases from various cement plants and 40 samples of exhaust gases from hospital and industrial waste incineration plants collected in 2009/2010 in the entire territory of Poland were examined. The average content of PCDDs/Fs in samples from cement plants amounted to 0.076 ng I-TEQ N m(-3) (range of 0.002-0.62 ng I-TEQ N m(-3)), while the average content of HCB amounted to 10 ng N m(-3) (range of 0.98-60.5 ng N m(-3)). In the case of samples collected from waste incineration plants, the average concentration of PCDDs/Fs was 0.39 ng I-TEQN m(-3) (range of 0.002-5.68 ng I-TEQ N m(-3)). In the case of HCB, the average concentration was 238 ng N m(-3) (range of 3.21-2500 ng N m(-3)). Also, the interdependence of the concentration of PCDDs/PCDFs and HCB was determined in the analysed samples, with the ranges of low and high content of PCDDs/PCDFs being examined separately. In all cases, the determined values of the r correlation coefficient were within the range of 0.7-1.0, which indicates a good correlation between the concentrations of PCDDs/PCDFs and HCB.     

An analysis of flaring and venting activity in the Alberta upstream oil and gas industry

Alberta, Canada, is an important global producer of petroleum resources. In association with this production, large amounts of gas (1.14 billion m3 in 2008) are flared or vented. Although the amount of flaring and venting has been measurably reduced since 2002, data from 2005 reveal sharp increases in venting, which have important implications in terms of resource conservation and greenhouse gas emissions (which exceeded 8 million tonnes of carbon dioxide equivalent in 2008). With use of extensive monthly production data for 18,203 active batteries spanning the years 2002-2008 obtained in close cooperation with the Alberta Energy Resources Conservation Board, a detailed analysis has been completed to examine activity patterns of flaring and venting and reasons behind these trends in the Alberta upstream oil and gas industry. In any given year, approximately 6000 batteries reported flaring and/or venting, but the distribution of volumes flared and vented at individual sites was highly skewed, such that small numbers of sites handled large fractions of the total gas flaring and venting in the Province. Examination of month-to-month volume variability at individual sites, cast in terms of a nominal turndown ratio that would be required for a compressor to capture that gas and direct it into a pipeline, further revealed that volumes at a majority of sites were reasonably stable and there was no evidence that larger or more stable sites had been preferentially reduced, leaving potential barriers to future mitigation. Through linking of geospatial data with production data coupled with additional statistical analysis, the 31.2% increase in venting volumes since 2005 was revealed to be predominantly associated with increased production of heavier oils and bitumen in the Lloydminster region of the Province. Overall, the data suggest that quite significant reductions in flaring and venting could be realized by seeking mitigation solutions for only the largest batteries in the Province.     

Mean Annual Temperature and Total Annual Precipitation Trends at Canadian Biosphere Reserves

This article examines instrumental climate records from a varietyof stations associated with the following Biosphere Reserves across Canada: (i) Waterton Lakes, (ii) Riding Mountain, (iii) Niagara Escarpment, (iv) Long Point, and (v) Kejimkujik (Candidate Biosphere Reserve). Annual series are generated fromdaily temperature and precipitation values. In addition, homogeneous data are used from other stations and regional records to supplement the records from the local biosphere stations. Long term trends are identified over the period of the instrumental record. In general, data from the interval 1900 to 1998 show cooler temperatures in the 1920's, warmingfrom the early 1940's into the early 1950's, cooling into the1970's, and subsequent warming. At many stations, 1998 is the warmest in the instrumental record. Comparisons with the regional data sets show good agreements between the temperatureseries. The 20th century warming is approximately 1.0 °C in the Riding Mountain area and 0.6 °Cin the Long Point, Niagara Escarpment, and Waterton Lakes areas.There has been slight cooling in the Kejimkujik area over the past half century. Precipitation data show increasing trends inthe Kejimkujik, Long Point, Niagara Escarpment, and Waterton Lakes areas with no long term trend in the Riding Mountain area. This work is part of the Canadian Biosphere Reserves Association (CBRA) Climate Change Initiative (CCI), designed to present climate change information to Biosphere Reserve communities to allow local organizations to understand climate change and adapt to potential impacts.     

National contributions to global ecosystem values

Current conservation templates prioritize biogeographic regions with high intensity ecosystem values, such as exceptional species richness or threat. Intensity-based targets are an important consideration in global efforts, but they do not capture all available opportunities to conserve ecosystem values, including those that accrue in low intensity over large areas. We assess six globally-significant ecosystem values—intact wilderness, freshwater availability, productive marine environments, breeding habitat for migratory wildlife, soil carbon storage, and latitudinal potential for range shift in the face of climate change—to highlight opportunities for high-impact broadly-distributed contributions to global conservation. Nations can serve as a cohesive block of policy that can profoundly influence conservation outcomes. Contributions to global ecosystem values that exceed what is predicted by a nation's area alone, can give rise to countries with the capacity to act as ‘conservation superpowers’, such as Canada and Russia. For these conservation superpowers, a relatively small number of national policies can have environmental repercussions for the rest of the world.     

Validation of FLACS against experimental data sets from the model evaluation database for LNG vapor dispersion

The siting of facilities handling liquefied natural gas (LNG), whether for liquefaction, storage or regasification purposes, requires the hazards from potential releases to be evaluated. One of the consequences of an LNG release is the creation of a flammable vapor cloud, that may be pushed beyond the facility boundaries by the wind and thus present a hazard to the public. Therefore, numerical models are required to determine the footprint that may be covered by a flammable vapor cloud as a result of an LNG release. Several new models have been used in recent years for this type of simulations. This prompted the development of the “Model evaluation protocol for LNG vapor dispersion models” (MEP): a procedure aimed at evaluating quantitatively the ability of a model to accurately predict the dispersion of an LNG vapor cloud.This paper summarizes the MEP requirements and presents the results obtained from the application of the MEP to a computational fluid dynamics (CFD) model – FLACS. The entire set of 33 experiments included in the model validation database were simulated using FLACS. The simulation results are reported and compared with the experimental data. A set of statistical performance measures are calculated based on the FLACS simulation results and compared with the acceptability criteria established in the MEP. The results of the evaluation demonstrate that FLACS can be considered a suitable model to accurately simulate the dispersion of vapor from an LNG release.     

Evidence of behavioral co-option from context-dependent variation in mandible use in trap-jaw ants (Odontomachus spp.)

Evolutionary co-option of existing structures for new functions is a powerful yet understudied mechanism for generating novelty. Trap-jaw ants of the predatory genus Odontomachus are capable of some of the fastest self-propelled appendage movements ever recorded; their devastating strikes are not only used to disable and capture prey, but produce enough force to launch the ants into the air. We tested four Odontomachus species in a variety of behavioral contexts to examine if their mandibles have been co-opted for an escape mechanism through ballistic propulsion. We found that nest proximity makes no difference in interactions with prey, but that prey size has a strong influence on the suite of behaviors employed by the ants. In trials involving a potential threat (another trap-jaw ant species), vertical jumps were significantly more common in ants acting as intruders than in residents (i.e. a dangerous context), while horizontal jumps occurred at the same rate in both contexts. Additionally, horizontal jump trajectories were heavily influenced by the angle at which the substrate was struck and appear to be under little control by the ant. We conclude that while horizontal jumps may be accidental side-effects of strikes against hard surfaces, vertical escape jumps are likely intentional defensive behaviors that have been co-opted from the original prey-gathering and food-processing functions of Odontomachus jaws.     

Predicting a ‘tree change’ in Australia's tropical savannas: Combining different types of models to understand complex ecosystem behaviour

In this study, key ecological modelling limitations of a process-based simulation model and a Bayesian network were reduced by combining the two approaches. We demonstrate the combined modelling approach with a case study investigating increases in woody vegetation density in northern Australia's tropical savannas. We found that by utilising the strengths of a simulation model and a Bayesian network we could both forecast future change in woody vegetation density and diagnose the reasons for current vegetation states. The local conditions of climate, soil characteristics and the starting population of trees were found to be more important in explaining the likelihood of change in woody vegetation density compared to management practices such as grazing pressure and fire regimes. We conclude that combining the strengths of a process and BN model allowed us to produce a simple model that utilised the ability of the process model to simulate ecosystem processes in detail and over long time periods, and the ability of the BN to capture uncertainty in ecosystem response and to conduct scenario, sensitivity and diagnostic analysis. The overall result was a model that has the potential to provide land managers with a better understanding of the behaviour of a complex ecosystem than simply utilising either modelling approach in isolation.     

Rapid onset of mate quality assessment via chemical signals in a woodland salamander (<Emphasis Type="Italic">Plethodon cinereus</Emphasis>)

In the competition to acquire mates, environmental factors can be important in determining the relative quality of an individual. These aspects of quality are often conveyed through signals used for mate assessment by the most energetically invested sex. In red-backed salamanders, Plethodon cinereus, chemical signals communicate a surprising amount of information, much of which is dependent on the current condition of the sender. One such condition-dependent aspect of information conveyed via chemicals is the quality of the sender’s diet, but it is unclear as to whether this information is actively advertised by the sender (i.e., a signal) or simply inferred from food-derived odors (i.e., a cue). The amount of time on different diets required for changes in signaling is also unknown. I examined how quickly gravid female salamanders could detect a difference between the scents of males on high- vs. low-quality diets without fecal cues. The amount of protein present in two known signaling glands (the mental and postcloacal glands) was also measured after experimental feeding. Gravid females were able to infer the differences in male diet quality after only 1 week. Females also responded to the male scents more quickly after differential feeding had begun. High-quality males had significantly more protein present in both signaling glands than low-quality males. This scenario highlights the ongoing interplay between the quality of an individual and its environment, with males actually advertising the status of this relationship as an honest signal for mate assessment.