Phosphorus removal from secondary sewage and septage using sand media amended with biochar in constructed wetland mesocosms.

To improve the performance efficiency of subsurface constructed wetlands (CWs), a variety of media have been tested. Recently, there has been a rising interest in biochar. This research aims to develop the effectiveness of sand media amended with biochar and two plants species (Melaleuca quinquenervia and Cymbopogon citratus) in removing phosphorus from sewage effluent in CWs. The experimental design consisted of vertical flow (VF) mesocosms with seven media treatments based on the proportions of biochar in the sand media which ranged from 0 to 25% by volume. During the first 8months, the mesocosms were loaded with secondary clarified wastewater (SCW) then septage was used for the remaining 8months. Inflow and outflow were monitored for total phosphorus (TP) and PO4-P. Plants were harvested at the end of the experiment and TP biomass was determined. Removal efficiencies of TP in the mesocosms loaded with SCW and septage ranged from 42 to 91% and 30 to 83%, respectively. Removal efficiencies of PO4-P ranged from 43 to -92% and 35 to 85% for SCW and septage, respectively. The results revealed that the sand media performed better than the biochar-amended media; increasing the proportion of biochar in the media decreased removal efficiency of phosphorus. However, after flushing due to major rain event, there was no significant difference between sand and sand augmented with 20% biochar. Total plant P ranged from 1.75g in the 20% biochar mesocosm to 2.10g in the sand only mesocosm. Plant uptake of P, at least in part, may be accredited for the better P removal efficiency in the sand media compared to the biochar-amended media.

An investigation into the effectiveness of sand media amended with biochar to remove BOD5, suspended solids and coliforms using wetland mesocosms.

Constructed wetland ecotechnologies (CWEs) are a promising solution to effectively treat domestic wastewater in developing countries at low cost. This paper reports the findings of the effectiveness of sand media amended with woody biochar and two plants species (Melaleuca quinquenervia and Cymbopogon citratus) in removing biological oxygen demand (BOD5), suspended solids and coliforms. The experimental design consisted of 21 vertical flow (VF) mesocosms. There were seven media treatments using sand amended with varying proportions of biochar. During the first 8 months, the mesocosms were loaded with secondary clarified wastewater (SCW) then septage. The influent had a 4-day hydraulic retention time. Samples were monitored for BOD5, total suspended solids (TSS), total volatile solids (TVS), total coliforms and faecal coliforms. In the first 8 months, there were no significant performance differences between media treatments in the outflow concentrations of BOD5, TSS and TVS. The significant differences occurred during the last 3 months; using septage with biochar additions performed better than pure sand. For coliforms, the significant differences occurred after 6 months. In conclusion, the addition of biochar was not effective for SCW. The VF mesocosms system proved to be more effective in removing BOD5, TSS, TVS and coliforms when septage was loaded into the media.

Separate and combined effects of dehydration and thirst sensation on exercise performance in the heat.

Using intravenous infusion, we separated the physiologic consequences of 3% body mass dehydration from the conscious awareness of fluid replacement on time trial (TT) performance in the heat. Eleven trained cyclists performed 90 min of steady-state (50% V ˙ O 2 peak ) cycling followed by a self-paced 20-km TT in a hot-dry (35 °C, 10% relative humidity, wind speed 3.0 m/s) environment while euhydrated-not thirsty (EU-NT), euhydrated-thirsty (EU-T), dehydrated-not thirsty (DH-NT), or dehydrated-thirsty (DH-T). Thirst was manipulated by providing (NT) or withholding (T) ad libitum 35 °C water oral rinse. Distinct hydration states existed, with 0.4 ± 0.5% dehydration following the 20-km TT (EU) compared with 3.2 ± 0.6% in DH (P < 0.001). Greater perceived thirst existed in T (7 ± 2 on a 1-9 scale) than NT (4 ± 2, P < 0.001) after the TT. No significant differences in power output existed during the TT between hydration (EU 202.9 ± 36.5 W vs DH 207.0 ± 35.9 W, P = 0.362) and thirst conditions (NT 203.3 ± 35.6 W vs T 206.6 ± 36.8 W, P = 0.548), nor were there differences in completion time (P = 0.832) or pacing profile (P = 0.690). Within the range of up to 3% body mass loss, neither the physiologic effects from lowered hydration status nor the perception of thirst, separately or combined, affected sustained submaximal exercise performance in the heat for a healthy and fit population.

Macrophyte zonation in stormwater wetlands: getting it right! A case study from subtropical Australia.

In Australia stormwater wetlands are becoming an increasingly popular component of water sensitive urban design. However, they must be designed to cope with the dynamic nature of urban hydrology, in particular, fluctuations in water level. The concept of macrophyte zonation relies on a thorough understanding of the water regimes of different plant species. Water depth is crucial and the hydroperiod, i.e. duration and frequency of inundation, has a significant impact on the survival of wetland vegetation. The aim of this study was to investigate plant establishment in a newly constructed stormwater wetland in Brisbane, subtropical Australia. Changes in plant distribution and density have been monitored since 2001. Rainfall and water depth data enabled us to use a hydrologic model to predict the extent of inundation of the different macrophytes zones. The field survey showed macrophyte survival was poor with the complete loss of several species in marsh and ephemeral zones. The main reason for the lack of macrophyte establishment and survival was the extended periods of inundation (supported by the hydrologic model) and deeper water levels. Stormwater wetlands must be designed to ensure that ephemeral species are not permanently inundated or the preferred water depths in marsh zones are not exceeded for extended periods.

Removal of dissolved nitrogen, phosphorus and carbon from stormwater by biofiltration mesocosms.

Biofiltration systems are becoming a popular stormwater treatment device in water sensitive urban design for the removal of fine particulate and dissolved pollutants from stormwater. However, there is limited published data on the effectiveness of these systems for nutrient removal. We constructed biofiltration mesocosms to assess nutrient removal (nitrogen, phosphorus and carbon) under experimental conditions. Different types of media were compared (gravel, sand, and sandy-loam) in vegetated and non-vegetated mesocosms (six treatments in total). Five plant species were used. Vegetated sand and vegetated sandy-loam provided the best overall treatment. Vegetated mesocosms were very effective in removing nitrogen (63-77% removal) and phosphorus (85-94% removal) from synthetic stormwater, and removed substantially more nutrients than the non-vegetated treatments. All treatments removed a substantial portion of the carbon from the stormwater (28-66%). When flushed with tap water, nitrogen and phosphorus were retained by the vegetated mesocosms, but leached from the non-vegetated mesocosms. Plant growth was most vigorous in the sandy-loam media, indicating that this is a good growth media, even without the addition of organic matter.

Progranulin mutations and amyotrophic lateral sclerosis or amyotrophic lateral sclerosis-frontotemporal dementia phenotypes.

OBJECTIVE: Mutations in the progranulin (PGRN) gene were recently described as the cause of ubiquitin positive frontotemporal dementia (FTD). Clinical and pathological overlap between amyotrophic lateral sclerosis (ALS) and FTD prompted us to screen PGRN in patients with ALS and ALS-FTD. METHODS: The PGRN gene was sequenced in 272 cases of sporadic ALS, 40 cases of familial ALS and in 49 patients with ALS-FTD. RESULTS: Missense changes were identified in an ALS-FTD patient (p.S120Y) and in a single case of limb onset sporadic ALS (p.T182M), although the pathogenicity of these variants remains unclear. CONCLUSION: PGRN mutations are not a common cause of ALS phenotypes.

Elevated serum angiogenin levels in ALS.

BACKGROUND: The role of hypoxia responsive genes in the pathogenesis of ALS was first suggested when deletions of the hypoxia-responsive element of vascular endothelial growth factor (VEGF) promoter caused a motor neuron disease phenotype in mice. The discovery of ALS-associated mutations in ANG, a hypoxia responsive gene coding for the protein angiogenin, has further supported this pathogenic mechanism in human ALS. In endothelium, angiogenin can regulate expression of VEGF. To date, the patterns of serum angiogenin expression among patients with ALS have not been assessed. METHODS: Serum angiogenin and VEGF levels were quantified at diagnosis in 79 patients with definite or probable ALS and 72 healthy controls, using a quantitative sandwich enzyme-linked immunoassay. RESULTS: Patients with ALS exhibited higher serum angiogenin (p = 0.006) but not VEGF (p = 0.55) levels than matched control subjects. Subgroup analysis showed a greater elevation in angiogenin levels for spinal- (p < 0.001) than bulbar- (p = 0.11) onset ALS vs controls. At 12 months, angiogenin levels remained elevated. No correlation was noted between angiogenin and VEGF levels (r = -0.08, p = 0.49) in ALS patient serum. CONCLUSION: These data suggest a modest elevation in serum angiogenin in ALS at diagnosis. Further investigation will be required to assess the utility of serum angiogenin as a biomarker for ALS and as a predictor of disease progression.

Association of the H63D polymorphism in the hemochromatosis gene with sporadic ALS.

Iron misregulation promotes oxidative stress and abnormally high iron levels have been found in the spinal cords of patients with ALS. The authors investigated whether HFE gene polymorphisms, linked to hemochromatosis, are associated with ALS using two independent populations of patients with sporadic ALS and controls (totaling 379 patients and 400 controls). They found that the H63D polymorphism is overrepresented in individuals with sporadic ALS (odds ratio 1.85, CI: 1.35 to 2.54).

A novel candidate region for ALS on chromosome 14q11.2.

Sequence variations with biologic effect in ALS have been identified in the gene for vascular endothelial growth factor (VEGF). The gene for a related protein, angiogenin, lies on chromosome 14q11.2. Analysis of the angiogenin (ANG) gene in the authors' population has demonstrated a significant allelic association with the rs11701 single nucleotide polymorphism (SNP) and identified a novel mutation in two individuals with sporadic ALS that potentially inhibits angiogenin function. These observations propose a candidate region for ALS on chromosome 14q11.2 and suggest that other genes with similar function to VEGF may be important in the pathogenesis of ALS.

Quantification of biofilms in a sub-surface flow wetland and their role in nutrient removal.

Subsurface flow wetlands contain gravel or sand substrates through which the wastewater flows vertically or horizontally. The aims of this study were, firstly, to quantify biofilm development associated with different size gravel in sections of a subsurface flow wetland with and without plants, and secondly, to conduct laboratory experiments to examine the role of biofilms in nutrient removal. Techniques to quantify biofilm included: bacterial cell counts, EPS and total protein extraction. Based on comparative gravel sample volume, only EPS was greater on the smaller 5 mm gravel particles. There was no significant difference between biofilm growth in sections with and without plants. Two vertical flow laboratory-scale reactors, one containing fresh wetland gravel, the other containing autoclaved gravel, were constructed to determine nutrient transformations. The autoclaved gravel in the "sterile" reactor rapidly became colonised with biofilm. Both reactors were dosed with two types of influent. Initially the influent contained 7.25 mg/L NO3-N and 0.3 mg/L NH4-N; the biofilm reactor removed most of the ammonium and nitrite but nitrate concentrations were only reduced by 20%. In the "sterile" reactor there was negligible removal of ammonium and nitrite indicating little nitrification, however nitrate was reduced by 72%, possibly due to assimilatory nitrate reduction associated with new biofilm development. When the influent contained 3 mg/L NO3-N and 16 mg/L NH4-N almost 100% removal and transformation of NH4-N occurred in both reactors providing an effluent high in NO3-N. Organic P was reduced but inorganic soluble P increased possibly due to mineralisation.

Nutrient removal and plant biomass in a subsurface flow constructed wetland in Brisbane, Australia.

Four native plant species (Baumea articulata, Carex fascicularis, Philydrum lanuginosum and Schoenoplectus mucronatus) are being investigated for their suitability in subsurface flow wetlands. The pilot scale Oxley Wetland, Brisbane, consists of 4 cells with different sized gravel (5 mm and 20 mm). The project aims to investigate nutrient removal rates and removal efficiency; nutrient storage in plant biomass; effect of cropping on plant regrowth, and the effect of gravel size on both water treatment and plant growth. Average daily mass removal rates ranged from 7.3 Kgha(-1)d(-1) NH4-N in Cell D to 4.6 Kgha(-1)d(-1) in Cell C i.e. 37%-22% removal efficiency respectively; 5.2 Kgha(-1)d(-1) NOx-N in Cell C to 1.3 Kgha(-1)d(-1) in Cell A (i.e. 75%-22% removal efficiency) and 0.8 Kgha(-1)d(-1) PO4-P in Cell A to 0.1 Kgha(-1)d(-1) in Cell C (i.e. 10%-1% removal efficiency). Cell A was the youngest wetland with new 5 mm gravel. Plant biomass was highest for Baumea and Carex. Gravel size does not appear to have affected biomass and recovery following cropping. Carex consistently had the highest harvested above ground biomass with high re-growth following cropping. Cropping appears to have retarded growth of the other three species with Schoenoplectus consistently having slowest regrowth. Plant biomass and nutrient storage was highest in Cell A and accounted for 11% of nitrogen removal and 3% of phosphorus removal.

An assessment of mosquito breeding and control in four surface flow wetlands in tropical-subtropical Australia.

In Queensland, Australia, the tropical-subtropical climate is ideal to promote macrophyte growth in surface flow wetlands; however, there have been concerns that constructed wetlands are potential breeding sites for disease-bearing mosquitoes. The aim of this study was to assess whether mosquitoes were breeding in these constructed wetlands, and if so, where they breed, and what parameters might influence breeding: e.g. water quality, vegetation, or macroinvertebrate communities. A study of four surface flow constructed wetlands located in different climatic regions was undertaken. Mosquito larvae were sampled using 240 ml dippers and macroinvertebrates using dip nets. The wetland with the greatest biodiversity of macrophytes and macroinvertebrates had the least number of mosquito larvae (< 1% of all dips). Samples with most mosquito larvae occurred amongst dense mats of Paspalum grass or dead Typha. Despite the presence of larvae in some parts of these wetlands very few late instars or pupae were found i.e. completion of the mosquito life cycle to adult mosquitoes was unsuccessful. This study has shown that the presence of mosquito larvae can be minimised by increasing macroinvertebrate biodiversity, by planting a variety of macrophyte types and species, excluding aggressive plant species, and maintaining at least 30% open water. Macroinvertebrates are probably a crucial factor in the control of mosquito larvae ensuring that predation of the early instars prevents or limits the development of pupae and the emergence of adults.

Suitability of macrophytes for nutrient removal from surface flow constructed wetlands receiving secondary treated sewage effluent in Queensland, Australia.

From a botanical perspective the major difference between waste stabilisation ponds and wetlands is the dominance of algae or floating plants in the former and emergent plants in the latter. Algae, floating and submerged plants remove nutrients directly from the water column whereas emergent species remove nutrients from the sediment. Water depth is a crucial factor in determining which plant types will become established. Surface flow constructed wetlands offer the greatest potential to grow a wide variety of different types of macrophytes. In assessing the suitability of plant species for nutrient removal, consideration must be given not only to nutrient uptake for growth but also storage of nutrients as plant biomass. A survey of macrophytes in 15 surface flow constructed wetlands treating secondary effluent was conducted in Queensland; 63 native species and 14 introduced species were found. Emergent species have been able to tolerate deeper water than in their natural environment and permanent waterlogging. All species grew well in the higher nutrient enriched wastewater. Submerged, floating leaved-attached and free floating species had the highest tissue nutrient content, followed by aquatic creepers. All these species remove nutrients from the water column. Emergent species had lower nutrient content but a greater biomass and were therefore able to store more nutrients per unit area of wetland. In order to maximise the efficiency of constructed wetlands for nutrient removal, a range of species should be used. Native species should be selected in preference to introduced/exotic species.

Metal accumulation in aquatic macrophytes from southeast Queensland, Australia.

To determine the extent of metal accumulation in some aquatic macrophytes from contaminated urban streams in southeast Queensland, plants were sampled from six sites, along with contiguous sediments. In all, 15 different species were collected, the most common genera being Typha (Cattails or Bulrushes) and Persicaria (Knotweeds). Before heavy metal analysis, plants were further separated into various morphological tissues, and five selected samples were separated into various physiological tissues. The cadmium, copper, lead and zinc content of the plants were analysed using flames AAS. In general, plant roots exhibited higher metal concentrations than the contiguous sediments. Of the metals of interest, only for zinc was there a relatively clear pattern of increasing accumulation in aquatic macrophytes with increasing sediment metal concentrations. Comparison between morphological tissues of the sampled plants found that roots consistently presented higher metal concentrations than either the stems or leaves, however unlike previous studies, this investigation revealed no consistent trend of stems accumulating more metals than the leaves. For Typha spp., metal concentrations followed the order of roots > rhizomes > leaves, while for Persicaria spp. the order was roots > leaves > stems. The submerged species Myriophyllum aquaticum accumulated the highest levels of metals overall (e.g. Zn 4300 micrograms g-1 dry weight and Cd 6.5 micrograms g-1), and the emergent macrophytes also exhibited relatively high metal contents in their roots. The leaves of the submerged and floating-leafed species collected contained relatively high quantities of the four metals of interest, compared with the leaves of emergent aquatic macrophytes. In the Typha rhizome and Persicaria stem samples analysed for internal variation in metal content, there was a pattern of increasing metal concentrations towards the external sections of the stem, both for subterranean stems (rhizomes) and above-substrate stems. For Persicaria stems, no clear pattern was observed for cadmium and lead, the two metals investigated that are not required by plants for survival.

Chronic subdural haematoma in the elderly--a North Wales experience.

Chronic subdural haematoma (CSDH) is predominantly a disease of the elderly. Most of the existing data come from studies done several decades ago. We examined the incidence, risk factors, clinical presentation, management and outcome in elderly patients with CSDH by retrospective study of the period 1996-1999 in the three district hospitals of North Wales. 40 cases of CSDH were identified in patients >65 years, the incidence in this population being 8.2/100,000. Falls (57%) and antithrombotic therapy (33%) were the most frequent risk factors. The most common presenting features were altered mental state (52%) and focal neurological deficit (50%). 24 patients (60%) underwent surgical intervention with 4 deaths (17%). In the non-operated group mortality was 7/16 (44%). Most of the deaths in this series were due either to CSDH or to the complications of frailty and poor mobility. Surgery itself was generally successful.

Hyperkalaemic quadriparesis secondary to chronic diclofenac treatment.

A 76 year old woman presented with a quadriparesis associated with hyperkalaemia. She had a 10 month history of treatment with oral diclofenac sodium. On admission she had hyperkalaemic metabolic acidosis with a normal anion gap and mild renal impairment. Her weakness resolved after withdrawal of diclofenac and medical correction of her hyperkalaemia. Non-steroidal anti-inflammatory drugs are known to cause hyperkalaemic acidosis and should be used with caution, especially in the presence of renal impairment.

Changes in plant biomass and nutrient removal over 3 years in a constructed wetland in Cairns, Australia.

The surface flow wetland in Cairns, Australia consists of 3 linear channels each 65 m long. Channels 1 and 2 are 5 m wide and Channel 3 is 15 m wide. The wetland was constructed in 1994 and band planted with emergent macrophyte species and alternating open water sections. The wetland was monitored for plant growth and nutrient removal until 1997. During that period HRT was 16 days in Channel 1 and 10 days in Channels 2 and 3; mass loading rates were 2.4 kg Total N and 2.0 kg Total P ha(-1) d(-1) in Channel 1 and 3.7 kg TN and 3.3 kg TP ha(-1) d(-1) in Channels 2 and 3. The aim of this work was to determine the proportion of nutrient removal that could be attributed to direct uptake by macrophytes and incorporated into plant biomass. Over the 3 year monitoring period reduction in total mass of nutrients was: Channel 1: 26% P, 85% N; Channel 2: 28% P, 87% N; Channel 3: 21% P, 81% N. Percentage reduction of FRP (Filterable Reactive Phosphorus) was similar to TP; NOx removal was 97-98%. Mass removal rates for TN and TP were higher in Channels 2 and 3 despite greater nutrient loading rates and shorter detention times. Total FRP removal was 23 kg P in Channel 1, 33 kg P in Channel 2 and 70 kg P in Channel 3 of which plant biomass accounted for 65%, 44% and 47% respectively. Total nitrogen removal was 92 kg in Channel 1,154 kg in Channel 2 and 386 kg in Channel 3 of which plant biomass accounted for 47%, 27% and 27% respectively. Thus, in this tropical surface flow wetland supporting a mixture of emergent macrophytes and floating duckweed, vegetation is an important mechanism for direct nutrient removal.

Medication-induced oesophageal injury leading to broncho-oesophageal fistula.

Medication-induced oesophageal injury is one of the least recognised side-effects of oral medication and, in contrast to other oesophageal pathologies, is rarely considered in the differential diagnosis of chest pain. We describe a case of medication-induced oesophageal injury with a rare complication in which the diagnosis was not considered until the characteristic features were demonstrated at endoscopy.