Health Status of Sand Flathead (Platycephalus bassensis), Inhabiting an Industrialised and Urbanised Embayment, Port Phillip Bay, Victoria as Measured by Biomarkers of Exposure and Effects

Port Phillip Bay, Australia, is a large semi-closed bay with over four million people living in its catchment basin. The Bay receives waters from the Yarra River which drains the city of Melbourne, as well as receiving the discharges of sewage treatment plants and petrochemical and agricultural chemicals. A 1999 study demonstrated that fish inhabiting Port Phillip Bay showed signs of effects related to pollutant exposure despite pollution management practices having been implemented for over a decade. To assess the current health status of the fish inhabiting the Bay, a follow up survey was conducted in 2015. A suite of biomarkers of exposure and effects were measured to determine the health status of Port Phillip Bay sand flathead (Platycephalus bassensis), namely ethoxyresorufin-O-deethylase (EROD) activity, polycyclic aromatic hydrocarbons (PAH) biliary metabolites, carboxylesterase activity (CbE) and DNA damage (8-oxo-dG). The reduction in EROD activity in the present study suggests a decline in the presence of EROD activity-inducing chemicals within the Bay since the 1990s. Fish collected in the most industrialised/urbanised sites did not display higher PAH metabolite levels than those in less developed areas of the Bay. Ratios of PAH biliary metabolite types were used to indicate PAH contaminant origin. Ratios indicated fish collected at Corio Bay and Hobsons Bay were subjected to increased low molecular weight hydrocarbons of petrogenic origin, likely attributed to the close proximity of these sites to oil refineries, compared to PAH biliary metabolites in fish from Geelong Arm and Mordialloc.Quantification of DNA damage indicated a localised effect of exposure to pollutants, with a 10-fold higher DNA damage level in fish sampled from the industrial site of Corio Bay relative to the less developed site of Sorrento. Overall, integration of biomarkers by multivariate analysis indicated that the health of fish collected in industrialised areas was compromised, with biologically significant biomarkers of effects (LSI, CF and DNA damage) discriminating between individuals collected in industrialised areas from observations made in fish collected in less developed areas of the Bay

Hormonal signaling in cnidarians : do we understand the pathways well enough to know whether they are being disrupted?

Author Posting. © The Author, 2006. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Ecotoxicology 16 (2007): 5-13, doi:10.1007/s10646-006-0121-1.Cnidarians occupy a key evolutionary position as basal metazoans and are ecologically important as predators, prey and structure-builders. Bioregulatory molecules (e.g., amines, peptides and steroids) have been identified in cnidarians, but cnidarian signaling pathways remain poorly characterized. Cnidarians, especially hydras, are regularly used in toxicity testing, but few studies have used cnidarians in explicit testing for signal disruption. Sublethal endpoints developed in cnidarians include budding, regeneration, gametogenesis, mucus production and larval metamorphosis. Cnidarian genomic databases, microarrays and other molecular tools are increasingly facilitating mechanistic investigation of signaling pathways and signal disruption. Elucidation of cnidarian signaling processes in a comparative context can provide insight into the evolution and diversification of metazoan bioregulation. Characterizing signaling and signal disruption in cnidarians may also provide unique opportunities for evaluating risk to valuable marine resources, such as coral reefs

Marine Tar Residues: a Review

Abstract Marine tar residues originate from natural and anthropogenic oil releases into the ocean environment and are formed after liquid petroleum is transformed by weathering, sedimentation, and other processes. Tar balls, tar mats, and tar patties are common examples of marine tar residues and can range in size from millimeters in diameter (tar balls) to several meters in length and width (tar mats). These residues can remain in the ocean envi-ronment indefinitely, decomposing or becoming buried in the sea floor. However, in many cases, they are transported ashore via currents and waves where they pose a concern to coastal recreation activities, the seafood industry and may have negative effects on wildlife. This review summarizes the current state of knowledge on marine tar residue formation, transport, degradation, and distribution. Methods of detection and removal of marine tar residues and their possible ecological effects are discussed, in addition to topics of marine tar research that warrant further investigation. Emphasis is placed on ben-thic tar residues, with a focus on the remnants of the Deepwater Horizon oil spill in particular, which are still affecting the northern Gulf of Mexico shores years after the leaking submarine well was capped

Determination of residual stresses by X-ray diffraction

This guide is applicable to X-ray stress measurements on crystalline materials. There is currently no published standard for the measurement of residual stress by XRD. This guide has been developed therefore as a source of information and advice on the technique. It is based on results from two UK intercomparison exercises, detailed parameter investigations and discussions and input from XRD experts. The information is presented in separate sections which discuss the fundamental background of X-ray diffraction techniques, the different types of equipment that can be used, practical issues relating to the specimen, the measurement procedure itself and recommendation on how and what to record and report. The appendices provide further information on uncertainty evaluation and some recommendations regarding the data analysis techniques that are available. Where appropriate key points are highlighted in the text and summarised at the end of the document

Microstructure and thermal stability of electrodeposited nanocrystalline nickel

Nanocrystalline nickel deposits have been prepared using electrodeposition in nickel sulphate based baths. The samples were characterised using microhardness testing, X-ray diffraction (XRD) and transmission electron microscopy (TEM).As-deposited samples showed a narrow grain size distribution with an average grain size of less than 20nm. The greatly increased microhardness of nanocrystalline materials, similar to 500kg/mm(2) for the Ni samples in this study, and their other superior properties have many potential applications. However, the microstructure of nanocrystals is metastable, and grain growth occuring at elevated temperatures can lead to a deterioration of properties.In this work, we have studied grain growth in nanocrystalline Ni annealed at 250degreesC. TEM micrographs revealed that the type of growth is abnormal. 3D atom probe analysis gave no indication of gain boundary segregation in as-deposited materials, and the low levels of segregation found in material annealed for 60 minutes were clearly not sufficient to significantly inhibit grain growth.Upon annealing, an increase in hardness up to about 580kg/mm(2) occurred within the first 5 minutes. Despite fast abnormal grain growth inside the nanocrystalline Ni, the high hardness values were maintained for a surprisingly long time. Only after about 240 minutes when the volume fraction of abnormal grains was above 50%, did the hardness start to decrease significantly. A two-phase model is proposed to relate the hardness data to the observed microstructure

Adaptive numerical modelling of high temperature strength, creep and fatigue behaviour in Ni-based superalloys

The mechanical behaviour of high performance Ni alloys is required for many applications and where experimental data is not readily available then a suitable predictive approach would be beneficial. There are numerous routes to achieve this, however, here the data driven neural network method has been adopted to produce models for the tensile, creep and fatigue performance of nickel base alloys. These models have been successfully developed and tested against a range of criteria. The tensile and creep models have displayed excellent fidelity to known nickel alloy behaviour, while good correspondence was also achieved for the fatigue properties (both strain and stress controlled). Potential routes to further improve the performance of these models have been discussed

The effect of high temperature exposure on the tensile properties of TiAl alloys

The lightweight γ titanium aluminide alloys offer good mechanical properties for gas turbine applications at temperatures up to 700 °C. An important characteristic of these materials will be their mechanical performance after exposure to anticipated service temperatures. Thus cast Ti-46Al-2W and extruded Ti-46Al-5Nb-1W have been subjected to thermal exposure at temperatures between 500 and 700 °C for up to 1000 h. This showed that the bulk microstructure was stable and resulted in little or no change in tensile properties after exposure. However, once surface effects were included in the tensile properties, then the values of both room temperature tensile strength and ductility reduced significantly. The room temperature property reductions were thought to be associated with changes in the surface residual stress state. Other potential factors include premature surface cracking, due to either localised hydrogen or oxygen embrittlement

Oxygen reduction at sparse arrays of platinum nanoparticles in aqueous acid: hydrogen peroxide as a liberated two electron intermediate.

Electrodeposition methods are used to generate a sparse array of platinum nanoparticles on a glassy carbon electrode. Specifically electrodeposition from a 1 mM solution of H2PtCl6 in 0.5 M H2SO4 leads to surface coverages of 0.46% to 1.96% and nanoparticles of size 29 nm to 136 nm in diameter, using deposition times of 30 and 15 seconds. The reduction of oxygen at an array of 29 nm nanoparticles with a surface coverage of 0.46% showed voltammetric signals with a scan rate dependence consistent with a two electron reduction of O2 to H2O2 with the rate proportional to K0 exp(-α(E-Ef(0))/RT) and formal potential (Ef(0)) of -0.058 V vs. SHE, a standard electrochemical rate constant (k0) of ~10 cm s(-1) and a transfer coefficient (α) of 0.23. At higher Pt nanoparticle coverages, a scan rate dependence consistent with the partial further reduction of H2O2 to water becomes evident