The effects of river flooding on dioxin and PCBs in beef

In 2008-2010, samples of meat from 40 beef cattle, along with grass, soil and commercial feed, taken from ten matched pairs of flood-prone and control farms, were analysed for PCDD/Fs and PCBs. Concentrations were higher in soil and grass from flood-prone farms. The beef samples from flood-prone farms had total TEQ levels about 20% higher than on control farms. A majority of flood-prone farms (7/10) had higher median levels in beef than on the corresponding control farm. This first controlled investigation into PCDD/F and PCB contamination in beef produced on flood-prone land, presents robust evidence that flooding is a contaminant transfer mechanism to cattle raised on river catchments with a history of urbanisation and industrialisation. PCDD/F and PCB sources in these river systems are likely to be a result of the legacy of contamination from previous industrialisation, as well as more recent combustion activity or pollution events. Crow

Ablation debris control by means of closed thick film filtered water immersion

The performance of laser ablation generated debris control by means of open immersion techniques have been shown to be limited by flow surface ripple effects on the beam and the action of ablation plume pressure loss by splashing of the immersion fluid. To eradicate these issues a closed technique has been developed which ensured a controlled geometry for both the optical interfaces of the flowing liquid film. This had the action of preventing splashing, ensuring repeatable machining conditions and allowed for control of liquid flow velocity. To investigate the performance benefits of this closed immersion technique bisphenol A polycarbonate samples have been machined using filtered water at a number of flow velocities. The results demonstrate the efficacy of the closed immersion technique: a 93% decrease in debris is produced when machining under closed filtered water immersion; the average debris particle size becomes larger, with an equal proportion of small and medium sized debris being produced when laser machining under closed flowing filtered water immersion; large debris is shown to be displaced further by a given flow velocity than smaller debris, showing that the action of flow turbulence in the duct has more impact on smaller debris. Low flow velocities were found to be less effective at controlling the positional trend of deposition of laser ablation generated debris than high flow velocities; but, use of excessive flow velocities resulted in turbulence motivated deposition. This work is of interest to the laser micromachining community and may aide in the manufacture of 2.5D laser etched patterns covering large area wafers and could be applied to a range of wavelengths and laser types

The effect of laser power, traverse velocity and spot size on the peel resistance of a polypropylene/adhesive bond

Abstract The mean peel resistance force achieved with respect to variation in the laser power, incident spot traverse velocity and incident spot diameter between linear low density polyethylene film backed by a thin commercial adhesive coating that were bonded to a polypropylene substrate via thermal activation provided by a 27W CO 2 laser is discussed in this work. The results gathered for this work have been used to generate a novel empirical tool that predicts the CO 2 laser power required to achieve a viable adhesive bond for this material combination. This predictive tool will enable the packaging industry to achieve markedly increased financial yield, process efficiency, reduced material waste and process flexibility. A laser spot size dependent linear increase in laser line energy was necessary for this material combination, suggesting the minimal impact of thermal strain rate. Moreover a high level of repeatability around this threshold laser line energy was indicated, suggesting that laser activated adhesive bonding of such polymer films is viable. The adhesion between the material combination trialled here responded linearly to thermal load. In particular, when using the smallest diameter laser spot, it is proposed that the resulting high irradiance caused film or adhesive material damage; thus, resulting in reduced peel resistance force. The experimental work conducted indicated that the processing window of an incident CO 2 laser spot increases with respect to spot diameter, simultaneously yielding greater bond stability in the face of short-term laser variance

Environmental risk assessment of genetically modified crops: The use of molecular markers to trace insect and wind dispersal of Brassica napus pollen.

End of Project ReportThis project aimed to develop a better understanding of the potential risks of gene flow and to generate isolation distances required for genetically modified (GM) OSR. The study examined biotic (insect) and abiotic (wind) pollen dispersal over two seasons. A considerable portion of work was devoted to the development of molecular markers, to differentiate Brassica napus varieties from each other to distinguish them from their wild relatives. The project broadly aimed to study gene flow, via pollen movement, from OSR but specifically aimed to: ! Characterise B. napus cv. Marinka using molecular markers. ! Elucidate the distance travelled by OSR pollen by biotic dispersal. ! Elucidate the distance travelled by OSR pollen by abiotic dispersal. ! Elucidate pollination/seed set at various distances from a source crop using male sterile bait plants. ! Develop risk assessment/containment strategies

Organic contaminant content and physico-chemical characteristics of waste materials recycled in agriculture

A range of wastes representative of materials currently applied, or with future potential to be applied, to agricultural land in the UK as fertilisers and soil improvers or used as animal bedding in livestock production, were investigated. In addition to full physico-chemical characterization, the materials were analysed for a suite of priority organic contaminants. In general, contaminants were present at relatively low concentrations. For example, polychlorinated dibenzo-p-dioxins/dibenzofurans and polychlorinated biphenyls in biosolids and compost-like-outputs (CLOs) were, in most cases, between 5-50 times lower than proposed and implemented European limit values for biosolids or composts applied to agricultural land. However, the technical basis for these limits may need to be re-evaluated. Polybrominated, and mixed halogenated, dibenzo-p-dioxins/dibenzofurans are not currently considered in risk assessments of dioxins and dioxin-like chemicals, but were detected in the biosolids and compost-like-outputs and their potential contribution to the overall toxic equivalency will be assessed. Other, ‘emerging’ contaminants such as perfluoralkyl compounds (PFCs) and organophosphate flame retardants were detected in several of the waste materials, and their potential significance is discussed. The study is part of a wider research programme that will provide evidence to improve confidence in the use of waste-derived materials in agriculture and establish guidelines to protect the food chain where necessary

Underperforming policy networks : the biopesticides network in the United Kingdom

Loosely integrated and incomplete policy networks have been neglected in the literature. They are important to consider in terms of understanding network underperformance. The effective delivery and formulation of policy requires networks that are not incomplete or underperforming. The biopesticides policy network in the United Kingdom is considered and its components identified with an emphasis on the lack of integration of retailers and environmental groups. The nature of the network constrains the actions of its agents and frustrates the achievement of policy goals. A study of this relatively immature policy network also allows for a focus on network formation. The state, via an external central government department, has been a key factor in the development of the network. Therefore, it is important to incorporate such factors more systematically into understandings of network formation. Feedback efforts from policy have increased interactions between productionist actors but the sphere of consumption remains insufficiently articulated

Analyzing the properties promoting shear bands and damage initiation in 3-point bending of ultra-high strength steel

Ultra-high strength steels (UHSS) have been developed to reduce the weight and increase strength capability of high value products such as crane structures. The bendability of UHSS steels has limited its application in production as their yield strength has increased, the bendability has been found to reduce with the reduction of tensile ductility. In this paper, the material properties affecting bendability in UHSS have been investigated and factors have been identified by analysing specimens pre and post bend testing [1-3] using a combined approach of in- and ex-situ small mechanical testing, Digital Image Correlation (DIC), modelling and characterisation. The propagation of shear bands in bending has been identified as the mechanism promoting damage in the tensile face to occur in the bending of steels. Identifying these factors combined to promote failure is of great importance while also developing a practical approach to identifying procedures to improve bendability. A small-scale bend test with new tooling and specimen geometry has been conducted inside the chamber of a Camscan SEM to observe the propagation of shear bands and damage initiation at the scale of the microstructure. Micrographs produced during the test were processed using DIC to study shear band formation in relation to strain distributions. Using these techniques shear bands and damage are observed at the tensile surface of the bend test. The strain localises in shear bands in a bifurcating pattern from the tensile surface in bending. Damage initiates at the surface where these shear bands intersect promoting a high strain at the surface. This damage promotes the shear bands to move through the sub-surface promoting further deformation then promoting more damage when the plasticity is exhausted. In this test a large 5µm inclusion is observed to interact with shear bands and seen to affect the damage propagation of the specimen and localise high strains at a region local to it. This region is where the failure originates from. Further analysis of the interaction between subsurface properties and the localisation of strain and shear bands will be studied