Towards consistency, rigour and compatibility of risk assessments for ecosystems and ecological communities

Ecosystem-level conservation is increasingly important at global, national and local levels. Many jurisdictions have developed and apply their own protocols for assessing the threat status of ecosystems, often independently, leading to inconsistencies between and within countries which are problematic for cross-jurisdictional environmental reporting. Australia is a good example of these historic legacies, with different risk assessment methods applied nationally and in most states. The newly developed criteria for the International Union for the Conservation of Nature (IUCN) Red List of Ecosystems (RLE) provide a framework to compare and contrast apparently divergent protocols. We critically reviewed the Australian protocols and compared them with the IUCN RLE, based on the following components of a risk assessment protocol: (i) categories of threat; (ii) assessment units; (iii) underlying concepts and definitions; (iv) assessment criteria; (v) uncertainty methods; and (vi) assessment outcomes. Despite some differences in specific objectives, criteria and their expression, the protocols were structurally similar, included broadly similar types of criteria, and produced assessment outcomes that were generally concordant. Alignment with the IUCN RLE would not require extensive changes to existing protocols, but would improve consistency, rigour and robustness in ecosystem risk assessment across jurisdictions. To achieve this, we recommend: (i) more quantitative assessments of functional change; (ii) separation of management and policy considerations from risk assessment; and (iii) cross-referencing of assessment units in different jurisdictions. We argue that the focus on processes and ecological function, rather than only patterns, is key to robust risk assessment. © 2014 The Authors.

Structural characterization of rare intramolecularly (1,4-Te· · ·N) bonded diorganotellurides and their monomeric complexes with mercury(II) halides: metal assisted C-H· · ·X (Hg) interactions leading to supramolecular architecture

Monomeric tellurides 4-RC₆H₄(SB)Te [SB = 2-(4,4'-N0₂C₆H₄CH=NC₆H₃-Me); R = H, 1a; Me,1b; OMe, 1c], which incidentally represent the first example of a telluride with 1,4-Te···N intramolecular interaction, have been prepared and characterized by solution and solid-state ¹²⁵Te NMR, ¹³C NMR and X-ray crystallography. Interplay of weak C-H···O and C-H-··π{ interactions in the crystal lattice of 1b and1c are responsible for the formation of supramolecular motifs. These tellurides undergo expected oxidative addition reactions with halogens and interhalogens and also interact coordinatively with mercury(II) halides to give 1:2 complexes, HgX₂[4-RC₆H₄(SB)Te]₂ (X = CI, R = H, 2a; Me, 2b; OMe, 2c and X = Br, R = H, 3a; Me, 3b; and OMe, 3c) with no sign of Te-C bond cleavage, as has been reported for some 1,5-Te·· ·N(O) intramolecularly bonded tellurides. The complexes 2a and 3c are the first structurally characterized monomeric 1:2 adducts of mercury(II) halides with Te ligands. The 1,4-Te···N intramolecular interactions in the solid-state are retained in the complexes highlighting simultaneously the Lewis acid and base character of the Te(lI) atom. Packing of molecules in the crystal lattice of 2a
and 3c reveals that non-covalent C-H· . ·Cl/Br interactions involving metal-bound halogen atoms possess significant directionality and in
combination with coordinative covalent interactions may be of potential use in creating inorganic supramolecular synthons.

Determination of sodium oxalate in Bayer liquor using flow-analysis incorporating an anion exchange column and tris(2,2`-bipyridyl)ruthenium(II) chemiluminescence detection

Semi-automated flow injection instrumentation, incorporating a small anion exchange column coupled with tris(2,2′-bipyridyl)ruthenium(II) (Ru(bipy)₃²⁺) chemiluminescence detection, was configured and utilised to develop rapid methodology for the determination of sodium oxalate in Bayer liquors. The elimination of both negative and positive interferences from aluminium(III) and, as yet, unknown concomitant organic species, respectively are discussed. The robustness of the methodology was considerably enhanced by using the temporally stable form of the chemiluminescence reagent, tris(2,2′-bipyridyl)ruthenium(III) perchlorate in dry acetonitrile. Real Bayer process samples were analysed and the results obtained compared well with those performed using standard methods within industrial laboratories.

Determination of glyphosate mono-isopropylamine salt in process samples using flow injection analysis with tris(2,2`-bipyridyl)ruthenium(II) chemiluminescence detection

The mono-isopropylamine salt of glyphosate was selectively determined directly in industrial and commercial formulations using flow injection analysis with tris(2,2′-bipyridyl)ruthenium(II) chemiluminescence detection without the need for separation. Glyphosate and its mono-isopropylamine salt furnished detection limits of 7×10⁻⁹ and 3.5×10⁻¹⁰ M and relative standard deviations of 0.4% at 1×10⁻⁷ M and 0.8% at 5×10⁻⁸ M, respectively. The methodology is robust and reliable with samples subjected only to aqueous dilution prior to analysis.

Recent developments in carbon nanotube membranes for water purification and gas separation

Carbon nanotubes (CNTs) are nanoscale cylinders of graphene with exceptional properties such as high mechanical strength, high aspect ratio and large specific surface area. To exploit these properties for membranes, macroscopic structures need to be designed with controlled porosity and pore size. This manuscript reviews recent progress on two such structures: (i) CNT Bucky-papers, a non-woven, paper like structure of randomly entangled CNTs, and (ii) isoporous CNT membranes, where the hollow CNT interior acts as a membrane pore. The construction of these two types of membranes will be discussed, characterization and permeance results compared, and some promising applications presented.

Role of angiotensin II in the hypertension induced by renal artery stenosis

Identical degrees of renal artery stenosis were induced in 5 dogs on two separate occasions; once during continuous inhibition of angiotensin I converting enzyme with enalapril, and once with the dogs untreated. Arterial pressure rose about 25 mm Hg during 3 days of stenosis in untreated dogs, due to increased total peripheral resistance. When the dogs were treated with enalapril, blood pressure had risen 14.5 ± 3.4 mm Hg 24 hours after stenosis due to a 35% increase in cardiac output while total peripheral resistance fell by 16%. By the third day, blood pressure had returned to pre-stenosis levels, cardiac output was close to normal and total peripheral resistance had increased. The stenosis on the renal artery increased the resistance to blood flow of the kidneys in both untreated and enalapril treated dogs. This increase in kidney resistance in the untreated dogs accounted for about 30% of the change in total peripheral resistance. In the enalapril treated dogs, the increased kidney resistance helped offset the vasodilatation in the rest of the vasculature. These results suggest that angiotensin II mediated vasoconstriction of nonrenal vascular beds was responsible for about ⅔ of the hypertension following renal artery stenosis, and the resistance of the stenosis responsible for about ⅓.

Toughening of a carbon-fibre composite using electrospun poly(Hydroxyether of Bisphenol A) nanofibrous membranes through inverse phase separation and inter-domain etherification

The interlaminar toughening of a carbon fibre reinforced composite by interleaving a thin layer (~20 microns) of poly(hydroxyether of bisphenol A) (phenoxy) nanofibres was explored in this work. Nanofibres, free of defect and averaging several hundred nanometres, were produced by electrospinning directly onto a pre-impregnated carbon fibre material (Toray G83C) at various concentrations between 0.5 wt % and 2 wt %. During curing at 150 °C, phenoxy diffuses through the epoxy resin to form a semi interpenetrating network with an inverse phase type of morphology where the epoxy became the co-continuous phase with a nodular morphology. This type of morphology improved the fracture toughness in mode I (opening failure) and mode II (in-plane shear failure) by up to 150% and 30%, respectively. Interlaminar shear stress test results showed that the interleaving did not negatively affect the effective in-plane strength of the composites. Furthermore, there was some evidence from DMTA and FT-IR analysis to suggest that inter-domain etherification between the residual epoxide groups with the pendant hydroxyl groups of the phenoxy occurred, also leading to an increase in glass transition temperature (~7.5 °C).

π-Selective stationary phases: (II) Adsorption behaviour of substituted aromatic compounds on n-alkyl-phenyl stationary phases

The frontal analysis method was used to measure the adsorption isotherms of phenol, 4-chlorophenol, p-cresol, 4-methoxyphenol and caffeine on a series of columns packed with home-made alkyl-phenyl bonded silica particles. These ligands consist of a phenyl ring tethered to the silica support via a carbon chain of length ranging from 0 to 4 atoms. The adsorption isotherm models that fit best to the data account for solute–solute interactions that are likely caused by π–π interactions occurring between aromatic compounds and the phenyl group of the ligand. These interactions are the dominant factor responsible for the separation of low molecular weight aromatic compounds on these phenyl-type stationary phases. The saturation capacities depend on whether the spacer of the ligands have an even or an odd number of carbon atoms, with the even alkyl chain lengths having a greater saturation capacity than the odd alkyl chain lengths. The trends in the adsorption equilibrium constant are also significantly different for the even and the odd chain length ligands.

Simple and signal-off electrochemical biosensor for mercury(II) based on thymine-mercury-thymine hybridization directly on graphene

Abstract A simple, signal-off and reusable electrochemical biosensor was developed for sensitive and selective detection of mercury(II) based on thymine-mercury(II)-thymine (T-Hg²⁺-T) complex and the remarkable difference in the affinity of graphene with double strand DNA (ds-DNA) and single strand DNA (ss-DNA). Our system was composed of ferrocene-tagged probe DNA and graphene. Due to the noncovalent assembly, the ferrocene-tagged probe ss-DNA was immobilized on the surface of graphene nanosheets directly and employed to amplify the electrochemical signal. In the presence of Hg²⁺, the ferrocene-labeled T-rich DNA probe hybridized with target probe to form ds-DNA via the Hg²⁺-mediated coordination of T-Hg²⁺-T base pairs. As a result, the duplex DNA complex kept away from the graphene surface due to the weak affinity of graphene and ds-DNA, and the redox current decreased substantially. Meanwhile, the graphene decorated GCE surface was released for the reusability. Under the optimal conditions, the proposed sensor showed a linear concentration range from 25 pM to 10 μM with a detection limit of 5 pM for Hg²⁺ detection. The strategy afforded exquisite selectivity for Hg²⁺ against other metal ions in real environmental samples.

Removal of Pb (II) ions using polymer based graphene oxide magnetic nano-sorbent

Graphene oxide (GO) based magnetic nano-sorbent was synthesized by assembling the Fe3O4 and GO on the surface of polystyrene (denoted as PS@Fe3O4@GO). The morphology of the nano-sorbent was studied using scanning electron microscopy (SEM), while their individual nano-components were characterized using UV-visible spectroscopy, atomic force microscopy (AFM), zeta potential, transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The assembled nano-sorbent was further investigated for Pb (II) ions removal by optimizing the parameters including pH, temperature and contact time. The obtained data was modelled for adsorption kinetics, adsorption isotherms and thermodynamics. Kinetic experiments indicated the Pb (II) adsorption followed first order kinetics. The adsorption equilibrium data fits Langmuir isotherm model well and the adsorption process was found to be spontaneous. The adsorption capacity of the prepared nano-sorbent was estimated to be 73.52mgg-1, with a maximum removal of 93.78% at pH 6. The nano-sorbent can be regenerated by nitric acid (HNO3) for reuse. FT-IR and X-ray photoelectron spectroscopy (XPS) studies confirmed the interactions between the Pb (II) ions and the nano-sorbent.