Description:
This paper reports on the major cations (Ca, Mg, Na and K) and arsenic (As) compositions of surface waters collected from major creeks, rivers and lakes in Central Victoria (Australia). The surface waters were found to be neutral to alkaline (pH 6.7-9.4), oxidised (average redox potential (Eh) about 130 mV) and showed variable concentrations of dissolved ions (EC, about 51-4386
Description:
Arsenic is naturally associated with gold mineralisation and elevated in some soils and mine waste around historical gold mining activity in Victoria, Australia. To explore uptake, arsenic concentrations in children's toenail clippings and household soils were measured, and the microdistribution and speciation of arsenic in situ in toenail clipping thin sections investigated using synchrotron-based X-ray microprobe techniques. The ability to differentiate exogenous arsenic was explored by investigating surface contamination on cleaned clippings using depth profiling, and direct diffusion of arsenic into incubated clippings. Total arsenic concentrations ranged from 0.15 to 2.1
Description:
Arsenic is naturally associated with gold mineralisation and elevated in some soils and mine waste around historical gold mining activity in Victoria, Australia. To explore uptake, arsenic concentrations in children's toenail clippings and household soils were measured, and the microdistribution and speciation of arsenic in situ in toenail clipping thin sections investigated using synchrotron-based X-ray microprobe techniques. The ability to differentiate exogenous arsenic was explored by investigating surface contamination on cleaned clippings using depth profiling, and direct diffusion of arsenic into incubated clippings. Total arsenic concentrations ranged from 0.15 to 2.1
Description:
A sequential extraction procedure was used to investigate the influence of long-term phosphate fertilization on the distribution of cadmium throughout the major components of krasnozemic soils in the potato growing district located to the East of Ballarat, Victoria, Australia. The soil fractions investigated consisted of the water soluble, exchangeable, weakly bound to metal oxides, strongly bound to metal oxides, bound to organic material and residual. Other soil parameters, such as pHH2O, pHCaCl2, electrolytical conductivity and total organic material were investigated. The concentrations of Ca, Mg, Fe, Mn and Zn in each soil fraction were also measured. The total concentration of cadmium in the farmed soils had increased from the background level of 100.5
Description:
Human activity has, in the recent past resulted in substantial changes in land cover, ecosystem health, and the ability of affected ecosystems to return to their original state. This necessitates further human intervention to recreate the systems functions than the present. Earlier restoration activities have not been documented extensively. This hinders our efforts to identify approaches that might support further work. "From abstract"
Description:
Soil and mine waste around historical gold mining sites may have elevated arsenic concentrations. Recent evidence suggests some systemic arsenic absorption by residents in the goldfields region of Victoria, Australia. Victorian Cancer Registry and geochemical data were accessed for an ecological geographical correlation study, 1984-2003. Spatial empirical Bayes smoothing was applied when estimating standardised incidence ratios (SIRs) for cancers in 61 statistical local areas. The derived soil arsenic exposure metric ranged from 1.4 to 1857 mg/kg. Spatial autoregressive modelling detected increases in smoothed SIRs for all cancers of 0.05 (95% confidence interval (CI), 0.02-0.08) and 0.04 (0.01-0.07) per 2.7-fold increase in the natural log-transformed exposure metric for males and females, respectively, in more socioeconomically disadvantaged areas; for melanoma in males (0.05 (0.01-0.08) adjusted for disadvantage) and females (0.05 (0.02-0.09) in disadvantaged areas). Excess risks were estimated for all cancers (relative risk 1.21 (95% CI, 1.15-1.27) and 1.08 (1.03-1.14)), and melanoma (1.52 (1.25-1.85) and 1.29 (1.08-1.55)), for males and females, respectively, in disadvantaged areas in the highest quintile of the exposure metric relative to the lowest. Our findings suggest small but significant increases in past cancer risk associated with increasing soil arsenic in socioeconomically disadvantaged areas and demonstrate the robustness of this geospatial approach. Journal of Exposure Science and Environmental Epidemiology advance online publication, 21 March 2012.
Description:
Soil and mine waste around historical gold mining sites may have elevated arsenic concentrations. Recent evidence suggests some systemic arsenic absorption by residents in the goldfields region of Victoria, Australia. Victorian Cancer Registry and geochemical data were accessed for an ecological geographical correlation study, 1984-2003. Spatial empirical Bayes smoothing was applied when estimating standardised incidence ratios (SIRs) for cancers in 61 statistical local areas. The derived soil arsenic exposure metric ranged from 1.4 to 1857 mg/kg. Spatial autoregressive modelling detected increases in smoothed SIRs for all cancers of 0.05 (95% confidence interval (CI), 0.02-0.08) and 0.04 (0.01-0.07) per 2.7-fold increase in the natural log-transformed exposure metric for males and females, respectively, in more socioeconomically disadvantaged areas; for melanoma in males (0.05 (0.01-0.08) adjusted for disadvantage) and females (0.05 (0.02-0.09) in disadvantaged areas). Excess risks were estimated for all cancers (relative risk 1.21 (95% CI, 1.15-1.27) and 1.08 (1.03-1.14)), and melanoma (1.52 (1.25-1.85) and 1.29 (1.08-1.55)), for males and females, respectively, in disadvantaged areas in the highest quintile of the exposure metric relative to the lowest. Our findings suggest small but significant increases in past cancer risk associated with increasing soil arsenic in socioeconomically disadvantaged areas and demonstrate the robustness of this geospatial approach. Journal of Exposure Science and Environmental Epidemiology advance online publication, 21 March 2012.
Description:
Omega-3 fatty acids and probiotic bacteria were co-encapsulated in a single whey protein isolate (WPI)-gum Arabic (GA) complex coacervate microcapsule. Tuna oil (0) and Lactobacillus casei 431 (P) were used as models of omega-3 and probiotic bacteria, respectively. The co-microcapsules (WPI-P-O-GA) and L. casei containing microcapsules (WPI-P-GA) were converted into powder by using spray and freeze drying. The viability of L. casei was significantly higher in WPI-P-O-GA co-microcapsules than in WPI-P-GA. The oxidative stability of tuna oil was significantly higher in spray dried co-capsules than in freeze dried ones. Crown Copyright (C) 2015 Published by Elsevier Ltd. All rights reserved.
Description:
Tuna oil rich in omega-3 fatty acids was microencapsulated in whey protein isolate (WPI)–gum arabic (GA) complex coacervates, and subsequently dried using spray and freeze drying to produce solid microcapsules. The oxidative stability, oil microencapsulation efficiency, surface oil and morphology of these solid microcapsules were determined. The complex coacervation process between WPI and GA was optimised in terms of pH, and WPI-to-GA ratio, using zeta potential, turbidity, and morphology of the microcapsules. The optimum pH and WPI-to-GA ratio for complex coacervation was found to be 3.75 and 3 : 1, respectively. The spray dried solid microcapsules had better stability against oxidation, higher oil microencapsulation efficiency and lower surface oil content compared to the freeze dried microcapsules. The surface of the spray dried microcapsules did not show microscopic pores while the surface of the freeze dried microcapsules was more porous. This study suggests that solid microcapsules of omega-3 rich oils can be produced using WPI–GA complex coacervates followed by spray drying and these microcapsules can be quite stable against oxidation. These microcapsules can have many potential applications in the functional food and nutraceuticals industry.
Description:
The effect of three faults on the slope stability was studied for the Stage 1 open pit in an open cut mine in Australia. The faults were treated as joints using Barton's method, and the slope was under dry and partially saturated conditions. A finite element program in RocScience was used in the study, where the generalized Hoek-Brown criterion was employed for rock mass and the Mohr-coulomb criterion for the faults. It is found that the factor of safety of the slope decreased with the introduction of the fault structures. Furthermore, the fault structures created higher stress concentrations zones at the ends of the faults.
Description:
Finite element analysis incorporating the shear strength reduction method was applied to study the west slope stability of an open cut mine in Australia using Mohr–Coulomb and generalized Hoek–Brown criteria. The pit of the mine had multiphase excavations and reached 180 m in depth. The study investigated three slope configurations, namely, Stage 1 inter ramp slope 43°, Stage 2 inter ramp slope 49° and optimized Stage 2 slope 54°. When implementing the generalized Hoek–Brown failure criterion, the equivalent factor of safety was 1.96, 1.87 and 1.40 under dry slope for the three configurations, respectively. However, under partly saturated conditions, the optimised slope would have a factor of safety 1.16. Furthermore, the generalised Hoek–Brown criterion generated lower factors of safety than the Mohr–Coulomb failure criterion. The difference is related to an overestimation of the shear strength parameters by the linear Mohr–Coulomb criterion under low confining stresses compared with the non-linear Hoek–Brown.