Characterisation of sea-water intrusion in the Pioneer Valley, Australia using hydrochemistry and three-dimensional numerical modelling

Sea-water intrusion is actively contaminating fresh groundwater reserves in the coastal aquifers of the Pioneer Valley,north-eastern Australia. A three-dimensional sea-water intrusion model has been developed using the MODHMS code to explore regional-scale processes and to aid assessment of management strategies for the system. A sea-water intrusion potential map, produced through analyses of the hydrochemistry, hydrology and hydrogeology, offsets model limitations by providing an alternative appraisal of susceptibility. Sea-water intrusion in the Pioneer Valley is not in equilibrium, and a potential exists for further landward shifts in the extent of saline groundwater. The model required consideration of tidal over-height (the additional hydraulic head at the coast produced by the action of tides), with over-height values in the range 0.5-0.9 m giving improved water-table predictions. The effect of the initial water-table condition dominated the sensitivity of the model to changes in the coastal hydraulic boundary condition. Several salination processes are probably occurring in the Pioneer Valley, rather than just simple landward sea-water advancement from modern sources of marine salts. The method of vertical discretisation (i.e. model-layer subdivision) was shown to introduce some errors in the prediction of watertable behaviour.

End-of-life decision making in Europe and Australia - A physician survey

Background: The frequencies with which physicians make different medical end-of-life decisions (ELDs) may differ between countries, but comparison between countries has been difficult owing to the use of dissimilar research methods. Methods: A written questionnaire was sent to a random sample of physicians from 9 specialties in 6 European countries and Australia to investigate possible differences in the frequencies of physicians' willingness to perform ELDs and to identify predicting factors. Response rates ranged from 39% to 68% (N= 10 139). Using hypothetical cases, physicians were asked whether they would ( probably) make each of 4 ELDs. Results: In all the countries, 75% to 99% of physicians would withhold chemotherapy or intensify symptom treatment at the request of a patient with terminal cancer. In most cases, more than half of all physicians would also be willing to deeply sedate such a patient until death. However, there was generally less willingness to administer drugs with the explicit intention of hastening death at the request of the patient. The most important predictor of ELDs was a request from a patient with decisional capacity (odds ratio, 2.1-140.0). Shorter patient life expectancy and uncontrollable pain were weaker predictors but were more stable across countries and across the various ELDs (odds ratios, 1.1-2.4 and 0.9-2.4, respectively). Conclusion: Cultural and legal factors seem to influence the frequencies of different ELDs and the strength of their determinants across countries, but they do not change the essence of decision making.

Pyrrolizidine alkaloids in Senecio madagascariensis from Australia and Hawaii and assessment of possible livestock poisoning

The alkaloid content of Senecio madagascariensis collected from Australia and Hawaii was examined. Alkaloids were identified from the above ground whole plant (stems, leaves and flowers) by GUMS analysis and included: senecivernine, senecionine, integerrimine, senkirkine, mucronatinine, retrosine, usaramine, otosenine, acetylsenkirkine, desacetyldoronine, florosenine and doronine. Plant material collected from the Hawaiian Islands was found to be identical in pyrrolizidine alkaloid content to that from a single composite collection made from northern New South Wales, Australia. Overall, no appreciable differences in alkaloid content were found between locations, whereas variation among individual plants was evident. The average total pyrrolizidine alkaloid content varied from a low of 217 mu g/g to a high of 1990 mu g/g (dry weight basis) among the locations. Based on comparable alkaloid content and documented pyrrolizidine alkaloidosis cases from Australia, S. madagascariensis may pose a significant risk to livestock grazing heavily infested ranges on the Hawaiian Islands. (c) 2006 Elsevier Ltd. All rights reserved.

Assessing the Conservation Status and Threats to Priority Plants: a threat assessment approach and case study in South-East Queensland, Australia

bstract: During the Regional Forest Agreement (RFA) process in south-east Queensland, the conservation status of, and threats to, priority vascular plant taxa in the region was assessed. Characteristics of biology, demography and distribution were used to assess the species' intrinsic risk of extinction. In contrast, the threats to the taxa (their extrinsic risk of extinction) were assessed using a decision-support protocol for setting conservation targets for taxa lacking population viability analyses and habitat modelling data. Disturbance processes known or suspected to be adversely affecting the taxa were evaluated for their intensity, extent and time-scale. Expert opinion was used to provide much of the data and to assess the recommended protection areas. Five categories of intrinsic risk of extinction were recognised for the 105 priority taxa: critically endangered (43 taxa); endangered (29); vulnerable (21); rare (10); and presumed extinct (2). Only 6 of the 103 extant taxa were found to be adequately reserved and the majority were considered inadequately protected to survive the current regimes of threatening processes affecting them. Data were insufficient to calculate a protection target for one extant taxon. Over half of the taxa require all populations to be conserved as well as active management to alleviate threatening processes. The most common threats to particular taxa were competition from weeds or native species, inappropriate fire regimes, agricultural clearing, forestry, grazing by native or feral species, drought, urban development, illegal collection of plants, and altered hydrology. Apart from drought and competition from native species, these disturbances are largely influenced or initiated by human actions. Therefore, as well as increased protection of most of the taxa, active management interventions are necessary to reduce the effects of threatening processes and to enable the persistence of the taxa.

Organochlorine and heavy metal concentrations in blubber and liver tissue collected from Queensland (Australia) dugong (Dugong dugon)

Tissue samples of liver and blubber were salvaged from fifty-three dugong (Dugong dugon) carcasses stranded along the Queensland coast between 1996 and 2000. Liver tissue was analysed for a range of heavy metals and blubber samples were analysed for organochlorine compounds. Metal concentrations were similar in male and female animals and were generally highest in mature animals. Liver concentrations of arsenic, chromium, iron, lead, manganese, mercury and nickel in a number of individual animals were elevated in comparison to concentrations previously reported in Australian dugong. Dieldrin, DDT (and its breakdown products) and/or heptachlor epoxide were detected in 59% of dugong blubber samples. In general, concentrations of organochlorines were similar to those reported in dugong 20 years earlier, and were low in comparison to concentrations recorded from marine mammal tissue collected elsewhere in the world. With the exception of lead, the extent of carcass decomposition, the presence of disease or evidence of animal starvation prior to death did not significantly affect dugong tissue concentrations of metals or organochlorines. The results of the study suggest that bioaccumulation of metals and organochlorine compounds (other than dioxins) does not represent a significant risk to Great Barrier Reef dugong populations, particularly in the context of other pressures associated with coastal development and other anthropogenic activities. (c) 2004 Elsevier Ltd. All rights reserved.