Aluminium smelting : the toxicity, scale and longevity of fluoride pollution in the environment

The release of fluoride from the production of aluminium, and the subsequent impacts of deposition in the environment, is well documented (Weinstein and Davison, 2004). However, changes are occurring within the industry, driven by technological advances and growth in global manufacture, which have the potential to alter the impact of the aluminium industry on the environment. There needs to be a better understanding of the toxicity of Sodium hexafluoroaluminate (cryolite, Na3AlF6), the impact of modern operating procedures on the release of particulates in to the environment, and finally, an investigation of the longevity of fluoride concentrations in vegetation from industrial pollution once emissions cease (EU, 2008). The toxicity of cryolite exposure to 1st and 3rd instar Diamondback moth larvae (Plutella xylostella (L), Lepidoptera: Plutellidae) was studied through a series of bioassays. There were inter-stage variations in both the lethal and sub-lethal responses to cryolite, whereby low mortality corresponded with high sub-lethal effects and vice versa. A dose-related response threshold was observed in both instars indicating that the physical nature of cryolite plays a role in the toxic mode of action. The comparative toxicity of cryolite from the pot-rooms of Lynemouth smelter and pesticide Kryocide© (Cerexagri, Inc) was investigated along with the role of particle size and the purity of the cryolite particulate in the mode of action. Although both physical and chemical factors played a role in toxicity, these factors formed a hierarchy and the mode of action had a significantly over-riding chemical grounding. Dust samples were collected from the vicinity of Lynemouth smelter for a period of 10 months in order to quantify the impact of modern aluminium production on the environment. Although the volumes of dust collected at any one site were lower than the European Community Short Term Ambient Guideline Concentration of Particulate Matter, dust deposition corresponded with aluminium production rates at the smelter showing that, despite Better Available Technology at the smelter, modern aluminium production still impacts on the environment. When Anglesey Aluminium Metals Ltd ended its operations in September 2009, it created a unique opportunity to assess the long-term impacts of fluoride pollution on the environment. Samples of soil, leaves and lichens were collected to monitor the changes in fluoride content over a 15 month period. The results showed that fluoride contamination of vegetation from industrial processes had a short-term impact once emissions ceased and that mineral-based soils had limited potential as contaminating sources for plant uptake. The mode of action of cryolite toxicity and the impact of waste disposal and fugitive release of cryolite in to the environment are discussed.EThOS - Electronic Theses Online ServiceRio Tinto AlcanGBUnited Kingdo

Impact of dynamic sub-populations within grafted chains on the protein binding and colloidal stability of PEGylated nanoparticles

Polyethylene glycol grafting has played a central role in preparing the surfaces of nano-probes for biological interaction, to extend blood circulation times and to modulate protein recognition and cellular uptake. However, the role of PEG graft dynamics and conformation in determining surface recognition processes is poorly understood primarily due to the absence of a microscopic picture of the surface presentation of the polymer. Here a detailed NMR analysis reveals three types of dynamic ethylene glycol units on PEG-grafted SiO2 nanoparticles (NPs) of the type commonly evaluated as long-circulating theranostic nano-probes; a narrow fraction with fast dynamics associated with the chain ends; a broadened fraction spectrally overlapped with the former arising from those parts of the chain experiencing some dynamic restriction; and a fraction too broad to be observed in the spectrum arising from units closer to the surface/graft which undergo slow motion on the NMR timescale. We demonstrate that ethylene glycol units transition between fractions as a function of temperature, core size, PEG chain length and surface coverage and demonstrate how this distribution affects colloidal stability and protein uptake. The implications of the findings for biological application of grafted nanoparticles are discussed in the context of accepted models for surface ligand conformation

Weeds in the treated field - a realistic scenario for pollinator risk assessment?

In July 2013 the European Food Safety Authority (EFSA) released its final guidance on the risk assessment of plant protection products (PPPs) to bees1. One objective of the guidance was to produce a simple and cost effective first tier risk assessment scheme to ensure that the appropriate level of protection is achieved. However, recent impact analyses have indicated that the first tier of this risk assessment does not act effectively as a screen for compounds of low risk to bees. For example substances showing no toxicity to bees often fail the tier 1 risk assessment based on a worst-case exposure to flowering weeds inside the treated field. If realistic farming practices (e.g. tillage and herbicide applications) are considered, weeds are not usually prevalent in arable fields. It is therefore suggested that the scenarios in the guidance could be considered overly conservative and in some instances unrealistic. The EFSA guidance states that if <10% of the area of use is flowering weeds then the exposure route is not relevant in the 90th %ile case, and thus does not need to be considered. However, despite this, the option to generate data or refine assessments based on available data is questioned as no guidance for the assessment of the abundance of weeds is available. As part of an industry-led initiative we present and discuss the use of empirical evidence (i.e. occurrence and growth stage of weeds in control plots from herbicide efficacy field trials conducted for regulatory submission) to illustrate that the scenarios in the guidance document could be modified using currently available data to create a more effective tier 1 risk assessment and still ensure that the appropriate level of protection is achieved. We have demonstrated here that less than 2% of all weeds recorded in arable crop trials (represented here by wheat, oilseed rape, sugar beet, sunflower, potatoes, maize, peas and beans) are at a flowering growth stage; therefore in arable crops the flowering weeds scenario is not applicable for the 90th %ile exposure. For permanent crop trials (represented here by orchards and vines) 37% of weeds were recorded at a flowering growth stage. When the attractiveness and density data are considered, the percentage of attractive, flowering weeds which cover >10% of the ground area is only 12.3%, indicating that for permanent crops further investigation may be required as to whether this scenario is relevant

Exile Vol. XXIX No. 2

Photo by John Taylor 2 Poem by Ezra Pound 3 Photo by James Lundy 4 Balanced Budget by August West 5 The Lighter by John Zarchen 6-7 Photo by Theodore Granberg 8 Uptown by Christopher B. Brougham 9 Photo by Jeff Russell 9 Heartstrings by Pete Waters 10 Spell by Eric Stevenson 10 Mums by Mandy Wilson 10 A New Day by Chad Hussey 11 Photo by Chad Hussey 12 Solitare by Gordon Black 13-14 Photo by James Lundy 15 A Grave Day-Dream by John Zarchen 16 Photo by James Lundy 17 Photo by Pauela Theodotou 18 Reconciliation by R. T. Hayashi 19 Michigan Rt. 37 by Ruth Wick 20 Shenango Valley by August West 20 Photo by James Lundy 21 Drawing by Adrienne Wehr 22 Ultraviolet Blues by Kathy Shelton 23 New Orleans & The Silky Black Seams Of My Stockings by Kate Reynolds 23 Refraction by Pam Houston 23-31 Photo by James Lundy 32 A Midsummer Night\u27s... by R. T. Hayashi 33 Couch sleeping by Eric Stevenson 33 Before We Could Build by Kim Kiefer 34 Photo by Chad Hussey 35 The Legend Of The Bear Mother by Amy Pence 36 Photo by James Lundy 37 Cover Drawing by Peter Brooke -title pag

Human papillomavirus (HPV) related Oropharynx Cancer in the United Kingdom – An evolution in the understanding of disease aetiology

A rising incidence of oropharyngeal squamous cell carcinoma (OPSCC) incidence has occurred throughout the developed world, where it has been attributed to an increasing impact of human papillomavirus (HPV) on disease etiology. This report presents the findings of a multicenter cross-sectional retrospective study aimed at determining the proportion of HPV-positive and HPV-negative OPSCC within the United Kingdom. Archival tumor tissue blocks from 1,602 patients previously diagnosed with OPSCC (2002-2011) were collated from 11 centers. HPV status was determined with three validated commercial tests to provide valid data for 1,474 cases in total. Corresponding national incidence data from the same decade were obtained from UK Cancer registries. The overall proportion of HPV+ OPSCC between 2002 and 2011 was 51.8% [95% confidence interval (CI), 49.3-54.4], and this remained unchanged throughout the decade [unadjusted RR = 1.00 (95% CI, 0.99-1.02)]. However, over the same period, the incidence of OPSCC in the broader UK population underwent a 2-fold increase [age-standardized rate 2002: 2.1 (95% CI, 1.9-2.2); 2011: 4.1 (95% CI, 4.0-4.3)]. Although the number of OPSCCs diagnosed within the United Kingdom from 2002 to 2011 nearly doubled, the proportion of HPV+ cases remained static at approximately 50%. Our results argue that the rapidly increasing incidence of OPSCC in the United Kingdom cannot be solely attributable to the influence of HPV. The parallel increase in HPV+ and HPV- cases we documented warrants further investigation, so that appropriate future prevention strategies for both types of disease can be implemented.</p