Update on gender-affirming surgery Blake, William
Australasian journal of plastic surgery,
04/2024, Letnik:
7, Številka:
1
Journal Article
Recenzirano
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William Blake looks at advances in the provision of gender-affirming surgery and how plastic surgeons in Australia can respond to the need for better surgical care for gender-diverse people.
Fine sediment source fingerprinting techniques have been widely applied in agricultural river catchments. Successful source discrimination in agricultural environments depends on the key assumption ...that land-use source signatures imprinted on catchment soils are decipherable from those due to other landscape factors affecting soil and sediment properties. In this study, we re-examine this critical assumption by investigating (i) the physical and chemical basis for source discrimination and (ii) potential factors that may confound source un-mixing in agricultural catchments, including particle size and organic matter effects on tracer properties. The study is situated in the River Tamar, a predominantly agricultural catchment (920km2) in south-west England that has also been affected by mining. Source discrimination focused on pasture and cultivated land uses and channel banks. Monthly, time-integrated suspended sediment samples were collected across seven catchments for a 12-month period. Physical and chemical properties measured in source soils and sediment included fallout radionuclides (137Cs, excess 210Pb), major and minor element geochemical constituents, total organic carbon and particle size. Source discrimination was entirely dependent on differences in tracer property concentrations between surface and sub-surface soils. This is based on fallout radionuclide concentrations that are surface-elevated, while many geochemical properties are surface-depleted due to weathering and pedogenetic effects, although surface soil contamination can reverse this trend. However, source discrimination in the study catchments was limited by (i) rotation of cultivated and pasture fields resulting in reduced differences between these two sources, and (ii) the cultivated source signature resembling a mix of the pasture and channel bank sources for many tracer properties. Furthermore, a combination of metal pollution from abandoned historic mines and organic enrichment of sediment from upland areas of peaty soils resulted in the non-conservative behaviour of some tracer properties in several catchments. Differences in the particle size and organic carbon content of source soils could explain much of the variation in these properties in downstream sediment, rather than selective transport effects. Inconsistent relationships between particle size, organic carbon and tracer property concentrations further undermined the basis for the use of widely applied corrections to tracer datasets. Sensitivity analysis showed that correcting source tracer data for differences in organic matter can produce large changes to source contribution estimates that cannot be justified, and such corrections should not be used. Confounding factors related to poor source discrimination and non-conservative behaviour are highly likely to affect sediment fingerprinting studies in many agricultural catchments. As a result, estimates of source contributions in many fingerprinting studies may contain significant unquantified errors.
•Sediment source fingerprinting has been widely applied in agricultural catchments.•Discrimination of pasture and cultivated sources was limited by field rotation.•Historic pollution affected the conservative behaviour of some tracers.•Organic matter corrections cause unjustified changes to source estimates.
Eutrophication is a significant threat to surface water biodiversity worldwide, with excessive phosphorus concentrations being among the most common causes. Wetland ditches under these conditions ...shift from primarily submerged aquatic vegetation to algae or duckweed dominance, leading to excessive shading and anoxic conditions. Phosphorus, from both point (e.g. wastewater treatment works) and diffuse (largely agricultural runoff) sources, is currently the central reason for failure in the majority of surface water bodies in England to meet required water quality guidelines. This study assesses phosphorus storage in the ditch systems at West Sedgemoor, a designated site of special scientific interest. Elevated phosphorus concentrations in sediment was observed across the Moor up to 4220 mg Kg−1, almost 10 times that which may be expected from background levels. The highest concentrations were generally observed at the more intensively farmed sites in the north of the moor, near key inlets and the outlet. Based upon their chemical and physical properties, clear distinction was observed between sites outside and within the Royal Society of the Protection of Birds nature reserve, using principal component analysis.
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•Exceptionally high sediment P concentrations observed e.g. >4000 mg kg−1.•Higher P concentrations observed at the north of the moor, the inlets and outlet.•Principal component analysis distinguished sites by land management approaches.•Higher P concentrations observed near agricultural land compared to nature reserve.•Observations indicate relatively higher P input from agricultural land.
In the Mediterranean region, floods are expected to increase as a result of climate change and knowledge of soil erosion hot spots during exceptional rainfalls is required to support mitigation ...measures. This study quantifies the main sediment sources during an exceptional rainfall event in 2012 (235 mm) at the outlet of two catchments located in NE Spain. To this purpose, suspended sediments were collected during the flood event, complemented with entrapped sediments in mat taken one year after the event. We used fingerprinting methodology and applied the FingerPro unmixing model to estimate the contribution from main sources. The selected tracers clearly distinguished agricultural, rangeland, subsoil and channel banks as the four potential sources in both catchments. In the Vandunchil catchment, the 8 time-integrated suspended sediment samples revealed changes in source contribution during the 2-h sampling sequence. There were relatively high contributions from rangeland, agriculture and subsoil at the beginning of the sampling, representing 30, 40 and 35% of the total source contributions, respectively. Our records captured the delivery of pulses of eroded surface soil transported by runoff with direct connectivity to the stream. The sequence was followed by a sharp increase in channel bank contribution (up to 90%) in comparison to the other sources, reflecting streambank erosion and landslide occurrence, which manifested during the flood. In contrast, in the La Reina catchment, agricultural soils contributed the most (65%) and, together with subsoils (32%), were the main sources. These results reflect the effect of the higher connectivity and slope gradient of these cultivated fields of the La Reina catchment in comparison with those of the Vandunchil catchment.
We discuss the possibility of using different properties, such as radionuclides, geochemistry and magnetic measurements, as tracers to distinguish between potential sources during an exceptional event in upland Mediterranean catchments. Our results support the use of fingerprinting techniques to determine variations in source contribution and sediment provenance during flood events, as extreme rainfalls are main drivers of sediment mobilization and key factors in changing landscapes. This is essential in identifying vulnerable hot spots, in which early-stage interventions are needed, and for helping policy makers with management of soil and water resources.
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•Unique opportunity to capture soil response during an exceptional event of 235 mm.•Suspended sediment properties changed during the flood event.•Source contributions varied in response to the rainstorm in a short period.•Switch from soil sources to channel bank provenance was captured during the flood.•Land use and connectivity determined the suspended sediment provenance.
Fundamental to all life, phosphorus is an essential nutrient and, contrastingly, a significant threat to surface water biodiversity globally as one of the most common causes of eutrophication in ...surface waters worldwide. Freshwater wetland ditches affected by these conditions undergo a conversion from primarily submerged aquatic vegetation to algae or duckweed dominance, leading to anoxic conditions. However, macrophyte biomass harvesting in eutrophic water systems is a promising means of remediation and nutrient recycling. This study seasonally assesses spatial distribution and chemical fractionation of surface water phosphorus, as well as surface biomass abundance and total phosphorus content in the ditch systems at West Sedgemoor (Somerset, UK), a designated site of special scientific interest. Elevated phosphorus concentrations in the surface water were observed across the site, with all sites exceeding e hi the Common Standards Monitoring environmental quality standard value of 0.1 mg L−1 during summer and autumn Sites lacking hydrological flow connectivity with contaminated freshwater inputs, typically had lower surface water phosphorus concentrations than the rest of the moor, with localised hotspots associated with likely cattle related agricultural activity. Summer and autumn were determined as the dominant duckweed growth seasons, in which an estimated 39 kg of phosphorus could be removed via duckweed biomass harvesting, per harvest period.
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•Exceedingly high freshwater P concentrations observed e.g. >1.00 mg L−1.•Principal component analysis distinguished sites by hydrological management.•Hydrological management influenced freshwater P concentrations.•Duckweed dominance observed over algal blooms post spring.•Duckweed harvesting estimated to remove 39 kg of P per harvest period.
Sediment fingerprinting experiments have been used to demonstrate the sensitivity of numerical mixing model outputs to different particle size distributions in source materials and experimental ...sediment mixtures. The study aims to examine further grain size effects in the distribution of geochemical elements by soils through a laboratory experiment simulating mixing and sorting processes, to investigate if different size fractions are influencing fingerprinting analyses and unmixing model results. Multiple particle size fractions are analysed to understand the relationship between particle size and source signal through elemental signatures. FingerPro model was applied to unmix six experimental mixtures with known percentages contribution from three experimental sources. The experimental design comprised four different setups with a specific size fraction for sources (S) and mixtures (M). Setups A (S <63 and M <63 μm) and B (S <20 and M <20 μm) relies upon a comparable particle size fraction for sources and mixtures, while C (S <63 and M <20 with PSC) and D (S <63 and M <20) address particle size impacts simulating fine enrichment, with and without a single particle size correction factor, respectively. Tracers were extracted after applying two statistical tests, the range test (RT) and a combination of RT, Kruskal-Wallis (KW) and DFA tests thus obtaining the set of optimum tracers for each mixture. Our findings indicate that source apportionment results are sensitive to tracer selection and particle size. The most accurate source apportionment results were achieved when comparing sources and mixtures with the <63 μm grain-size fraction (setup A) by using the set of tracers extracted after RT, KW and DFA tests, (mean RMSE: 2%, AE: 2%). Larger errors were obtained progressively for setups B, C and D with better results when using more number of tracers from RT (mean RMSE: 7, 10, 13%, AE: 8, 11, 15%, respectively). The main strength of using experimental mixtures with a known contribution of the sources relies on reducing the uncertainty of the unmixing model outputs, one of the main limitations in fingerprint studies. The impact of SSA on the elemental concentration is difficult to predict because the positive linearity between them does not apply equally to all elements and this assumption needs to be constantly examined and considered for fingerprinting studies. Otherwise, the use of a single particle size correction factor could negatively affect unmixing results. The outcomes of this research will help to develop appropriate strategies for sediment fingerprinting, contributing to our knowledge of processes affecting sediment geochemistry and sediment transport across different particle sizes.
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•Relationships between SSA and elemental geochemistry are often non-linear.•Source apportionment results are sensitive to tracer selection and particle size.•Using particle size correction factors could negatively affect unmixing results.•Fingerprint studies need to account for particle size data of source and sediments.•Unreliable results if sources and mixtures have different particle size distribution.
Industrialised rivers contain legacy contaminants stored in their sediments and floodplain soils which may inhibit attainment of environmental quality criteria. The River Fal catchment, SW England, ...is impacted by inputs from uranium mining and clay production and serves as an exemplar for understanding the consequences of medium-term process dynamics in contaminated basins. Radionuclides were determined, by gamma spectroscopy, in six cores from the river floodplain with the aim of quantifying the activities of 238U, and its decay products, and the bomb fallout radionuclides137Cs and 241Am. Activity concentrations of 238U implied inputs from mining, accentuated by flood events and historic industrial accidents, whereas 210Pb activities included a significant input of unsupported 210Pb linked to processed mine spoil. The radionuclide inventories did not decrease systematically downstream revealing evidence of attenuation of particulate radionuclides within the river floodplain sediment column. Storage of legacy contaminants in fluvial systems, at levels in excess of contemporary environmental quality guidelines, emphasises the challenges posed by changing climatic conditions. This scenario raises significant consequences for the management of uranium-contaminated, fertile riverine floodplains within Europe.
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•An abandoned uranium mine on the River Fal (UK) is a source of legacy radionuclides.•High activities of 238U and its decay products are distributed within the river basin.•Floodplains were identified as important depositional zones for uranium pollution.•Similar pollution scenarios arising from redundant uranium mines exist in Europe.
Glaciers in most parts of the world are retreating, releasing water and sediments to downstream rivers. Studies have found elevated levels of fallout radionuclides (FRNs) and other contaminants in ...glacial sediments, especially cryoconite, in European glaciers and Greenland. However, there are no equivalent studies for glaciers in North America. We report concentrations of FRNs (i.e.
Cs,
Pb
and
Am) and other contaminants (i.e. metal(loids), phosphorus) in cryoconite and proglacial sediments from a glacier in British Columbia, Canada, and compare values to suspended sediments from the downstream river. The mean concentrations of
Cs,
Pb
and
Am in cryoconite were 2,123 ± 74, 7,535 ± 224 and 11.5 ± 3.0 Bq kg
, respectively, which are an order of magnitude greater than those for most soils and surficial materials. FRNs were much lower in suspended sediments and decreased with distance away from the glacier. Geochemical elements were enriched in cryoconite relative to local clastic materials and upper continental crust. Concentrations of FRNs in cryoconite were correlated with organic matter, which suggests this is important in controlling the scavenging of hydrophobic contaminants in glacial meltwater. Low concentrations of FRNs and contaminants in suspended sediments suggest that glacial meltwater and the delivery of cryoconite have limited impact on downstream aquatic ecosystems.
Evaluation of the spatial and temporal composition of floodplain sediments and soils is critical in the creation of soil management strategies for impacted riverine catchments. The objective of this ...study was to determine the distribution, and to identify the sources, of particulate trace elements and fallout radionuclides in the catchment of the River Avon (SW England), where sedimentary processes had been altered by reservoir construction in the 1950s. The catchment was compartmentalized into its main functional units namely, cultivated land, pasture, woodland, wet moorland, and channel bank. Surface soils were collected in each unit, along with four strategically-placed cores, all of which were analyzed for particle size, fallout radionuclides and elemental concentrations. Sediment particle sizes and sediment accumulation rates were affected by the construction of the reservoir, specifically the distributions of silt and clay. The concentrations of fertilizer constituent Cr and P were highly correlated in the mid-catchment but were unrelated downstream due to elevated concentrations of Cr from geological deposits. Copper, As, Pb and Sn had variable down-core distributions, with pulses in concentrations due to mining inputs. The contributions of the end-member sources of particulate elements in the sedimentary mixtures were evaluated, quantitatively, using a Bayesian Mixing Model and the cultivated land was identified as a significant contributor to the mixtures, independent of space and time. The results contribute to advances in soil quality and conservation measures as components of a catchment management plan for the Avon, an approach maybe applicable to other small catchments in the UK and internationally.
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•Elemental and radionuclide distributions were determined in floodplain sediments.•Natural and anthropogenic influences affect elemental distributions in the catchment.•Data synthesis via a Bayesian sediment mixing model and evaluation of elemental sources•Results support refinement of land management initiatives for farmed catchments.
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