Managing the potential public health risks from bioaerosol liberation at commercial composting sites in the UK: An analysis of the evidence base

The diversion of biodegradable waste from landfill is of key importance in developing a sustainable waste strategy for the next decade and beyond. The proliferation of waste treatment technologies such as Mechanical Biological Treatment, Anaerobic Digestion and Composting will be paramount in achieving this strategic goal. This paper evaluates the scientific information needed to undertake an effective assessment of the potential public health risks from exposure to bioaerosols in the vicinity of commercial composting activities. Knowledge gaps currently exist in the scientific and regulatory community that limit our ability to effectively characterise source-term emissions, develop reliable dose–response data and accurately model the dispersion of bioaerosols. Consequently reliable risk estimates cannot be developed to inform the management of these potential risks. This uncertainty may prove a barrier to progress in achieving waste diversion and composting targets in Wales and the rest of the UK. A robust and extensive evidence base is required to inform the risk assessment process. This paper advocates the need for further, more focussed research into hazard characterisation of viable and non-viable organisms, improved dose–response data, exposure assessment techniques and an evaluation of the existing risk control and mitigation measures currently adopted. It is hoped that his will enable effective, timely and proportional risk management and mitigation measures to be developed that will foster the confidence required in composting technologies to achieve waste diversion targets and develop sustainable waste strategies.     

Geochemical stability of phosphorus solids below septic system infiltration beds

Review of 10 mature septic system plumes in Ontario, revealed that phosphorus (P) attenuation commonly occurred close to the infiltration pipes, resulting in discrete narrow intervals enriched in P by a factor of 2-4 (. MSc thesis, Dept. Earth Sci., University of Waterloo, Waterloo, Ont.; Ground Water 36 (1995) 1000; J. Contam. Hydrol. 33 (1998) 405). Although these attenuation reactions appeared to be sustainable under present conditions, the potential for remobilization of this P mass, should geochemical conditions change, is unknown. To test the stability of these P solids, dynamic flow column tests were carried out using sediments from three of the previously studied sites (Cambridge, Langton and Muskoka) focusing on sediments from the 'High-P' and underlying (Below) zones. Tests were continued for 166-266 pore volumes (PVs), during which time varying degrees of water saturation were maintained. During saturated flow conditions, relatively high concentrations of PO4 were eluted from the Cambridge and Langton High-P zones (up to 4 and 9 mg/l P, respectively), accompanied by elevated concentrations of Fe (up to 1.4 mg/l) and Mn (up to 4 mg/l) and lower values of Eh (<150 mV). The Below zones from Cambridge and Langton, however, maintained lower concentrations of P (generally<2 mg/l), Fe (<0.2 mg/l) and Mn (<1 mg/l) and maintained higher Eh (>250 mV) during saturated flow conditions. During unsaturated flow, P and Fe declined dramatically in the High-P zones (P<1 mg/l, Fe<0.2 mg/l), whereas concentrations remained about the same during saturated and unsaturated flow in the Below zones. This behavior is at least partly attributed to the development of reducing conditions during saturated flow in the High-P zones, leading to reductive dissolution of Fe (III)-P solids present in the sediments. Reducing conditions did not develop in the Below zones apparently because of lower sediment organic carbon (OC) contents (0.03-0.04 wt.%) compared to the High-P zones (0.2-0.65 wt.%). At the Muskoka site, where the sediments were noncalcareous, low values of P (<0.2 mg/l) were maintained in both the High-P and Below columns and reducing conditions did not develop. Results indicate the possibility of remobilizing P accumulated below septic system infiltration beds should conditions become more reducing. This could occur if sewage loading patterns change, for example when a seasonal use, lakeshore cottage is converted to a permanent dwelling.     

Evidence for high taxonomic and morphologic tyrannosauroid diversity in the Late Cretaceous (Late Campanian) of the American Southwest and a new short-skulled tyrannosaurid from the Kaiparowits formation of Utah

The fossil record of late Campanian tyrannosauroids of western North America has a geographic gap between the Northern Rocky Mountain Region (Montana, Alberta) and the Southwest (New Mexico, Utah). Until recently, diagnostic tyrannosauroids from the Southwest were unknown until the discovery of Bistahieversor sealeyi from the late Campanian of New Mexico. Here we describe an incomplete skull and postcranial skeleton of an unusual tyrannosaurid from the Kaiparowits Formation (Late Cretaceous) of Utah that represents a new genus and species, Teratophoneus curriei. Teratophoneus differs from other tyrannosauroids in having a short skull, as indicated by a short and steep maxilla, abrupt angle in the postorbital process of the jugal, laterally oriented paroccipital processes, short basicranium, and reduced number of teeth. Teratophoneus is the sister taxon of the Daspletosaurus + Tyrannosaurus clade and it is the most basal North American tyrannosaurine. The presence of Teratophoneus suggests that dinosaur faunas were regionally endemic in the west during the upper Campanian. The divergence in skull form seen in tyrannosaurines indicates that the skull in this clade had a wide range of adaptive morphotypes.     

Does a parthenogenesis-inducing <Emphasis Type="Italic">Wolbachia</Emphasis> induce vestigial cytoplasmic incompatibility?

Wolbachia is a maternally inherited bacterium that manipulates the reproduction of its host. Recent studies have shown that male-killing strains can induce cytoplasmic incompatibility (CI) when introgressed into a resistant host. Phylogenetic studies suggest that transitions between CI and other Wolbachia phenotypes have also occurred frequently, raising the possibility that latent CI may be widespread among Wolbachia. Here, we investigate whether a parthenogenesis-inducing Wolbachia strain can also induce CI. Parthenogenetic females of the parasitoid wasp Asobara japonica regularly produce a small number of males that may be either infected or not. Uninfected males were further obtained through removal of the Wolbachia using antibiotics and from a naturally uninfected strain. Uninfected females that had mated with infected males produced a slightly, but significantly more male-biased sex ratio than uninfected females that had mated with uninfected males. This effect was strongest in females that mated with males that had a relatively high Wolbachia titer. Quantitative PCR indicated that infected males did not show higher ratios of nuclear versus mitochondrial DNA content. Wolbachia therefore does not cause diploidization of cells in infected males. While these results are consistent with CI, other alternatives such as production of abnormal sperm by infected males cannot be completely ruled out. Overall, the effect was very small (9%), suggesting that if CI is involved it may have degenerated through the accumulation of mutations.     

Teaching industrial ecology and environmental management in Second Life

Second Life is a virtual, open-access, and user-generated environment that has served as a platform for hosting everything from rock concerts to scientific conferences. Many institutions have also used Second Life as an educational tool, for example by, showcasing scientific exhibits or embedding video and images for learning purposes. Here we discuss the creation and use of an interactive, virtual industrial facility - the Elihu Paper Company - as a way to complement a traditional facility tours in a course in industrial environmental management. Virtual facilities offer a number of educational advantages over real-life ones: they are always open and available for tours, they can be accessed instantaneously from anywhere where there is an adequate internet connection, and most importantly, tours and embedded information can be tailored to specific educational objectives. Our experience in using Elihu Paper as a formal facility visit for the past several years shows that students had significantly more time than usual to ask questions, could and did explore the facility independently, and were still able to produce facility reports that fulfilled the educational objectives of the visits, including mapping material flows and explaining pollution prevention and sustainability opportunities.     

A pore water study of plutonium in a seasonally anoxic lake

Data are presented here on the distribution of ^239,240Pu in the pore waters of two cores taken from a seasonally anoxic lake. The pore water ^239,240Pu profile exhibits a subsurface activity maximum of 230 ± 30 μBqkg^?1 in the 3–6 cm interval in June, as compared to an activity of 5 ± 3 μBqkg^?1 in the overlying water. The pore water ^239,240Pu profile in June follows the solid phase distribution pattern of ^239,240Pu and also the pore water distributions of Fe and Mn. Under more reducing conditions in August, pore water ^239,240Pu activities drop off to undetectable levels at all depths. This rapid change in the pore water ^239,240Pu activity reflects the dynamic nature of Pu diagenesis in these sediments. Potential diffusional fluxes of ^239,240Pu into the lake's hypolimnion in June are calculated to be on the order of 2·5 μBq cm^?2y^?1. This flux would not be significant in altering the solid phase ^239,240Pu inventory (2·8 × 10⁴μBqcm^?2).     

Examining the colonization process of exotic species varying in competitive abilities using a cellular automaton model

Current threats of invasive species have significant implications for ecological systems. Given their potential impacts, invasive species have been the subject of extensive empirical and theoretical studies. However, these studies have tended to focus on species that produce highly visible ecological and economic impacts. In our study, we take a step back from focusing on these high-impact invasive species, and examine the general colonization (invasion) process of exotic species that have various “competitive abilities” against the native species. Using a two-species cellular automaton model, we demonstrate that: (1) a threshold level of competitive ability is required for the exotic species to successfully establish in a new landscape and (2) an exotic species with superior competitive ability does not necessarily become dominant in a landscape (alternatively, a species that has inferior competitive ability may successfully colonize a new system). Our findings have significant implications for the study of species invasions and also provide clues to how species assemble in ecological communities.