Biomass burning influenced particles characteristics in Northern Territory Australia based on airborne measurements

Airborne measurements of particle number concentrations from biomass burning were conducted in the Northern Territory, Australia, during June and September campaigns in 2003, which is the early and the late dry season in that region. The airborne measurements were performed along horizontal flight tracks, at several heights in order to gain insight into the particle concentration levels and their variation with height within the lower boundary layer (LBL), upper boundary layer (UBL), and also in the free troposphere (FT). The measurements found that the concentration of particles during the early dry season was lower than that for the late dry season. For the June campaign, the concentration of particles in LBL, UBL, and FT were (685 ± 245) particles/cm3, (365 ± 183) particles/cm3, and (495 ± 45) particle/cm3 respectively. For the September campaign, the concentration of particles were found to be (1233 ± 274) particles/cm3 in the LBL, (651 ± 68) particles/cm3 in the UBL, and (568 ± 70) particles/cm3 in the FT. The particle size distribution measurements indicate that during the late dry season there was no change in the particle size distribution below (LBL) and above the boundary layer (UBL). This indicates that there was possibly some penetration of biomass burning particles into the upper boundary layer. In the free troposphere the particle concentration and size measured during both campaigns were approximately the same.

The influence of climate variability on hydrological processes and surface and groundwater hydrochemistry : the tropical upper roper river catchment, Northern Territory, Australia

The Upper Roper River is one of the Australia’s unique tropical rivers which have been largely untouched by development. The Upper Roper River catchment comprises the sub-catchments of the Waterhouse River and Roper Creek, the two tributaries of the Roper River. There is a complex geological setting with different aquifer types. In this seasonal system, close interaction between surface water and groundwater contributes to both streamflow and sustaining ecosystems. The interaction is highly variable between seasons. A conceptual hydrogeological model was developed to investigate the different hydrological processes and geochemical parameters, and determine the baseline characteristics of water resources of this pristine catchment. In the catchment, long term average rainfall is around 850 mm and is summer dominant which significantly influences the total hydrological system. The difference between seasons is pronounced, with high rainfall up to 600 mm/month in the wet season, and negligible rainfall in the dry season. Canopy interception significantly reduces the amount of effective rainfall because of the native vegetation cover in the pristine catchment. Evaporation exceeds rainfall the majority of the year. Due to elevated evaporation and high temperature in the tropics, at least 600 mm of annual rainfall is required to generate potential recharge. Analysis of 120 years of rainfall data trend helped define “wet” and “dry periods”: decreasing trend corresponds to dry periods, and increasing trend to wet periods. The period from 1900 to 1970 was considered as Dry period 1, when there were years with no effective rainfall, and if there was, the intensity of rainfall was around 300 mm. The period 1970 – 1985 was identified as the Wet period 2, when positive effective rainfall occurred in almost every year, and the intensity reached up to 700 mm. The period 1985 – 1995 was the Dry period 2, with similar characteristics as Dry period 1. Finally, the last decade was the Wet period 2, with effective rainfall intensity up to 800 mm. This variability in rainfall over decades increased/decreased recharge and discharge, improving/reducing surface water and groundwater quantity and quality in different wet and dry periods. The stream discharge follows the rainfall pattern. In the wet season, the aquifer is replenished, groundwater levels and groundwater discharge are high, and surface runoff is the dominant component of streamflow. Waterhouse River contributes two thirds and Roper Creek one third to Roper River flow. As the dry season progresses, surface runoff depletes, and groundwater becomes the main component of stream flow. Flow in Waterhouse River is negligible, the Roper Creek dries up, but the Roper River maintains its flow throughout the year. This is due to the groundwater and spring discharge from the highly permeable Tindall Limestone and tufa aquifers. Rainfall seasonality and lithology of both the catchment and aquifers are shown to influence water chemistry. In the wet season, dilution of water bodies by rainwater is the main process. In the dry season, when groundwater provides baseflow to the streams, their chemical composition reflects lithology of the aquifers, in particular the karstic areas. Water chemistry distinguishes four types of aquifer materials described as alluvium, sandstone, limestone and tufa. Surface water in the headwaters of the Waterhouse River, the Roper Creek and their tributaries are freshwater, and reflect the alluvium and sandstone aquifers. At and downstream of the confluence of the Roper River, river water chemistry indicates the influence of rainfall dilution in the wet season, and the signature of the Tindall Limestone and tufa aquifers in the dry. Rainbow Spring on the Waterhouse River and Bitter Spring on the Little Roper River (known as Roper Creek at the headwaters) discharge from the Tindall Limestone. Botanic Walk Spring and Fig Tree Spring discharge into the Roper River from tufa. The source of water was defined based on water chemical composition of the springs, surface and groundwater. The mechanisms controlling surface water chemistry were examined to define the dominance of precipitation, evaporation or rock weathering on the water chemical composition. Simple water balance models for the catchment have been developed. The important aspects to be considered in water resource planning of this total system are the naturally high salinity in the region, especially the downstream sections, and how unpredictable climate variation may impact on the natural seasonal variability of water volumes and surface-subsurface interaction.

Neoproterozoic glacial deposits of the Kimberly Region and northwestern Northern Territory, Australia

Neoproterozoic glacigenic formations are preserved in the Kimberley region and northwestern Northern Territory of northern Australia. They are distributed in the west Kimberley adjacent to the northern margins of the King Leopold Orogen, the Mt Ramsay area at the junction of the King Leopold and Halls Creek Orogens, and the east Kimberley, adjacent to the eastern margin of the Halls Creek Orogen. Small outlier glacigenic deposits are preserved in the Litchfield Province, Northern Territory (Uniya Formation) and Georgina Basin, western Queensland (Little Burke Formation). Glacigenic strata comprise diamictite, conglomerate, sandstone and pebbly mudstone and characterize the Walsh, Landrigan and Fargoo/Moonlight Valley formations. Thin units of laminated dolomite sit conformably at the top of the Walsh, Landrigan and Moonlight Valley formations. Glacigenic units are also interbedded with the carbonate platform deposits of the Egan Formation and Boonall Dolomite. δ13C data are available for all carbonate units. There is no direct chronological constraint on these successions. Dispute over regional correlation of the Neoproterozoic succession has been largely resolved through biostratigraphic, chemostratigraphic and lithostratigraphic analysis. However, palaeomagnetic results from the Walsh Formation are inconsistent with sedimentologically based correlations. Two stratigraphically defined glaciations are preserved in northwestern Australia: the ‘Landrigan Glaciation’, characterized by southwest-directed continental ice-sheet movement and correlated with late Cryogenian glaciation elsewhere in Australia and the world; and, the ‘Egan Glaciation’, a more localized glaciation of the Ediacaran Period. Future research focus should include chronology, palaeomagnetic constraint and tectonostratigraphic controls on deposition.

Discriminating stromatolite formation modes using rare earth element geochemistry: Trapping and binding versus in situ precipitation of stromatolites from the Neoproterozoic Bitter Springs Formation, Northern Territory, Australia

Stromatolites consist primarily of trapped and bound ambient sediment and/or authigenic mineral precipitates, but discrimination of the two constituents is difficult where stromatolites have a fine texture. We used laser ablation-inductively coupled plasma-mass spectrometry to measure trace element (rare earth element – REE, Y and Th) concentrations in both stromatolites (domical and branched) and closely associated particulate carbonate sediment in interspaces (spaces between columns or branches) from bioherms within the Neoproterozoic Bitter Springs Formation, central Australia. Our high resolution sampling allows discrimination of shale-normalised REE patterns between carbonate in stromatolites and immediately adjacent, fine-grained ambient particulate carbonate sediment from interspaces. Whereas all samples show similar negative La and Ce anomalies, positive Gd anomalies and chondritic Y/Ho ratios, the stromatolites and non-stromatolite sediment are distinguishable on the basis of consistently elevated light REEs (LREEs) in the stromatolitic laminae and relatively depleted LREEs in the particulate sediment samples. Additionally, concentrations of the lithophile element Th are higher in ambient sediment samples than in stromatolites, consistent with accumulation of some fine siliciclastic detrital material in the ambient sediment but a near absence in the stromatolites. These findings are consistent with the stromatolites consisting dominantly of in situ carbonate precipitates rather than trapped and bound ambient sediment. Hence, high resolution trace element (REE + Y, Th) geochemistry can discriminate fine-grained carbonates in these stromatolites from coeval non-stromatolitic carbonate sediment and demonstrates that the sampled stromatolites formed primarily from in situ precipitation, presumably within microbial mats/biofilms, rather than by trapping and binding of ambient sediment. Identification of the source of fine carbonate in stromatolites is significant, because if it is not too heavily contaminated by trapped ambient sediment, it may contain geochemical biosignatures and/or direct evidence of the local water chemistry in which the precipitates formed.

Community night patrols in the Northern Territory : toward an improved performance and reporting framework

This Technical and Background Paper summarises the results of a Australian Government Attorney-General’s Department’s funded project. The project aimed to clarify the contribution of the community night patrol program in the Northern Territory (NT) to improving the community safety of Indigenous communities. The paper recommends an improved framework for monitoring performance and reporting. Community night patrols or similar services operate in many other areas of Australia and internationally. The paper concludes that the core business of community night patrols is (non-crisis) crime prevention not defacto policing. It also concludes that an unrecognised outcome of patrols is capturing and sharing local knowledge about community safety issues and solutions. Over time, community night patrols should focus on working with other services to reduce the need for repeat assistance to persons at risk and for risky incidents. The recently released Northern Territory Emergency Response Evaluation Report (2011) confirmed that communities and service providers surveyed largely support night patrols, but better data is required to more comprehensively assess their performance.

Rates of radiologically confirmed pneumonia as defined by the World Health Organization in Northern Territory Indigenous children

Objective To determine the burden of hospitalised, radiologically confirmed pneumonia (World Health Organization protocol) in Northern Territory Indigenous children. Design, setting and participants Historical, observational study of all hospital admissions for any diagnosis of NT resident Indigenous children, aged between >= 29 days and < 5 years, 1 April 1997 to 31 March 2005. Intervention All chest radiographs taken during these admissions, regardless of diagnosis, were assessed for pneumonia in accordance with the WHO protocol. Main outcome measure The primary outcome was endpoint consolidation (dense fluffy consolidation [alveolar infiltrate] of a portion of a lobe or the entire lung) present on a chest radiograph within 3 days of hospitalisation. Results We analysed data on 24 115 hospitalised episodes of care for 9492 children and 13 683 chest radiographs. The average annual cumulative incidence of endpoint consolidation was 26.6 per 1000 population per year (95% Cl, 25.3-27.9); 57.5 per 1000 per year in infants aged 1-11 months, 38.3 per 1000 per year in those aged 12-23 months, and 13.3 per 1000 per year in those aged 24-59 months. In all age groups, rates of endpoint consolidation in children in the arid southern region of NT were about twice that of children in the tropical northern region. Conclusion The rates of severe pneumonia in hospitalised NT Indigenous children are among the highest reported in the world. Reducing this unacceptable burden of disease should be a national health priority.

Hospitalisation of Indigenous children in the Northern Territory for lower respiratory illness in the first year of life

Objective To describe the epidemiology of acute lower respiratory infection (ALRI) and bronchiectasis in Northern Territory Indigenous infants hospitalised in the first year of life. Design A historical cohort study constructed from the NT Hospital Discharge Dataset and the NT Imm(u)nisation Register. Participants and setting All NT resident Indigenous infants, born 1 January 1999 to 31 December 2004, admitted to NT public hospitals and followed up to 12 months of age. Main outcome measures Incidence of ALRI and bronchiectasis (ICD-10-AM codes) and radiologically confirmed pneumonia (World Health Organization protocol). Results Data on 9295 infants, 8498 child-years of observation and 15 948 hospitalised episodes of care were analysed. ALRI incidence was 426.7 episodes per 1000 child-years (95% Cl, 416.2-437.2). Incidence rates were two times higher (relative risk, 2.12; 95% Cl, 1.98-2.27) for infants in Central Australia compared with those in the Top End. The median age at first admission for an ALRI was 4.6 months (interquartile range, 2.6-7.3). Bronchiolitis accounted for most of the disease burden, with a rate of 227 per 1000 child-years. The incidence of first diagnosis of bronchiectasis was 1.18 per 1000 child-years (95% Cl, 0.60-2.16). One or more key comorbidities were present in 1445 of the 3227 (44.8%) episodes of care for ALRI. Conclusions Rates of ALRI and bronchiectasis in NT Indigenous infants are excessive, with early onset, frequent repeat episodes, and a high prevalence of comorbidities. These high rates of disease demand urgent attention.

Dengue or Kokobera? A case report from the top end of the Northern Territory

In early April 1998, the Centre for Disease Control in Darwin was notified of a possible case of dengue which appeared to have been acquired in the Northern Territory. Because dengue is not endemic to the Northern Territory, locally acquired infection has significant public health implications, particularly for vector identification and control to limit the spread of infection. Dengue IgM serology was positive on two occasions, but the illness was eventually presumptively identified as Kokobera infection. This case illustrates the complexity of interpreting flavivirus serology. Determining the cause of infection requires consideration of the clinical illness, the incubation period, the laboratory results and vector presence. Waiting for confirmation of results, before the institution of the public health measures necessary for a true case of dengue, was ultimately justified in this case. This is a valid approach in the Northern Territory, but may not be applicable to areas of Australia with established vectors for dengue. Commun Dis Intell 1998;22:105-107.

A case of Kunjin virus encephalitis in a traveller returning from the Northern Territory

On 6 May 2001, a 67-year-old Australian born, Caucasian male presented to the Emergency Department of the Austin and Repatriation Medical Centre (A&RMC) with a 3 day history of fever, lethargy and confusion. This occurred one week after returning from a trip to the Northern Territory. His previous medical problems included ischaemic heart disease, a repaired abdominal aortic aneurysm, hypertension, hyperlipidaemia and congestive cardiac failure. He smoked 20 cigarettes per day and had a history of heavy alcohol consumption. He had no history of diabetes. His medications were aspirin, frusemide, lisinopril, simvastatin, and a nitroglycerol patch. Fifty years ago, he had an adverse reaction to penicillin with angioedema and an urticarial rash. Four weeks before admission he went on a fishing trip in the Northern Territory. He travelled by road, through outback regions of Victoria, New South Wales, Queensland, the Northern Territory and South Australia, spending time in Daly River, Coolum, Darwin, Dunmarra, Avon Downs, Innaminka and Mataranka. He was away for 3 weeks and camped in tents or outside in a swag throughout the trip. He recalls numerous times where he was exposed to mosquitoes with large numbers of bites at Dunmarra. During the time away, he remained well as did his 5 travelling companions. There was...

A case presenting diagnostic difficulties : making sense of flavivirus serology in the Top End of the Northern Territory

In early April 1998 the Centre for Disease Control (CDC) in Darwin was notified of a case with positive dengue serology. The illness appeared to have been acquired in the Northern Territory (NT). Because dengue is not endemic to the NT, locally acquired infection has significant public health implications, particularly for vector identification and control to limit the spread of infection. Dengue IgM serology was positive on two occasions but the illness was eventually presumptively identified as Kokobera infection. This case illustrates some important points about serology. The interpretation of flavivirus serology is complex and can be misleading, despite recent improvements. The best method of determining the cause of infection is still attempting to reconcile clinical illness details with incubation times and vector presence, as well as laboratory results. This approach ultimately justified the initial period of waiting for confirmatory results in this case, before the institution of public health measures necessary for a true case of dengue.

Hospital separations in the Northern Territory for varicella-zoster virus related illnesses, 1993-1997

A varicella-zoster virus (VZV) vaccine is available overseas, and universal immunisation in childhood is recommended in the United States.1 Any decision to introduce the vaccine to Australia must be based on an assessment of potential benefits and harms. While there has been some assessment of VZV significance in populations in southern Australia,2 the impact on the NT population is not known. It is not a notifiable condition and information on morbidity and mortality is limited to a few data collections. These are hospital separation data, deaths registers, and in 1995 the inclusion of VZV congenital and neonatal complications in the Australian Paediatric Surveillance System. Hospital separation data were analysed to assess the importance of VZV as a cause of severe morbidity and mortality in the NT population.