https://ogma.newcastle.edu.au/vital/access/ /manager/Index ${session.getAttribute("locale")} 5 https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:29511 Cucumis sativa L. (cucumber). The parameter log K_f was predicted with soil pH_ca, logCEC and log OC. Transfer of soil pore-water Cd²⁺ to shoots was described with a power function (R² = 0.73). The dataset was validated with 13 long-term contaminated soils (plus 2 control soils) ranging in Cd concentration from 0.2 to 300 mg kg⁻¹. The series of equations predicting Cd_shoot from pore-water Cd²⁺ were able to predict the measured data in the independent dataset (root mean square error = 2.2). The good relationship indicated that Cd uptake to cucumber shoots could be predicted with Cd_pore and Cd²⁺ without other pore-water parameters such as pH or Ca²⁺. The approach may be adapted to a range of plant species.]]> Wed 23 Feb 2022 16:06:46 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:24098 in vitro data for barite contaminated soils using the physiologically based extraction test (PBET) methodology. The existence of barite in plant tissue and the possibility of 'biomineralised' zones was also investigated using Scanning Electron Microscopy. Soils with low barium (Ba) concentrations showed a higher proportion of Ba extractability than barite rich samples. Barium uptake to spinach from soil was different between short term spiking studies and field weathered soils. Furthermore, Ba crystals were not evident in spinach tissue or acid digest solutions grown in barium nitrate spiked soils despite high accumulation. Barite was found in the plant digest solutions from barite contaminated soils only. Results indicate that under the conservative assumptions made, a child would need to consume extreme quantities of soil over an extended period to cause chronic health problems.]]> Wed 10 Nov 2021 15:05:34 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:43123 Tue 13 Sep 2022 14:39:25 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:51641 Tue 12 Sep 2023 20:15:54 AEST ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:31400 Cucumis sativa L) conducting 4 weeks pot study in 5 different soils spiked with As (0, 2, 4, 8 to 1024 mg kg_{-1 ) individually and with Zn at two phytotoxic doses. The As pore-water concentration was significantly reduced (df = 289, Adjusted R² = 0.84, p < 0.01) in the presence of Zn in the whole dataset, whereas Zn and Zn²⁺ activity in pore-water was reduced significantly only in the two alkaline soils. This outcome may be due to adsorption/surface precipitation or tertiary bridging complexation. No homogenous precipitation of zinc arsenate could be established using electron microscopy, XRD or even equilibrium calculations. For bioaccumulation phase, no significant effect of Zn on As uptake was observed except acidic MG soil whereas, Zn uptake was significantly reduced (p < 0.05) by As in whole dataset. However, an additive response was observed mostly except acidic MG soil. The synergistic response (more than additive) was predominant in this soil for a wide range of inhibition concentration (0¿80%) at both Zn EC10 and EC50 levels. Since additive response is mostly considered in risk assessment for mixtures, precautions should be implemented for assessment of toxicity for As-Zn mixture in acidic soil due to their synergistic response in some soils.]]>} Sat 24 Mar 2018 08:43:26 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:29932 Cucumis sativa L) using 10 contrasting soils. Arsenate phytotoxicity was shown to be related to soluble carbonate and phosphate. The data indicated that dissolved phosphate and carbonate had an antagonistic impact on arsenate toxicity to cucumber. To predict arsenate phytotoxicity in soils with a diverse range of soil solution properties, both carbonate and phosphate were required. The relationship between arsenic and pore-water toxicity parameters was established initially using multiple regression. In addition, based on the relationship with carbonate and phosphate we successively applied a terrestrial biotic ligand-like model (BLM) including carbonate and phosphate. Estimated effective concentrations from the BLM-like parametrization were strongly correlated to measured arsenate values in pore-water (R² = 0.76, P < 0.001). The data indicates that an ion interaction model similar to the BLM for arsenate is possible, potentially improving current risk assessments at arsenic and co-contaminated soils.]]> Sat 24 Mar 2018 07:30:55 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:29927 Cucumis sativa L. (cucumber) focusing primarily on pore-water Pb data from 10 different soils after 12 weeks ageing. Phytotoxicity expressed in terms of Pb²⁺ was observed to occur in the nanomolar range in neutral to alkaline soils (EC50 values 90 to 853 nM) and micromolar levels for acidic soils (EC50 values 7.35 to 9.66 μM). Internal Pb concentrations relating to toxicity (PT50) in roots and shoots also decreased with increasing pore-water pH (R² = 0.52 to 0.53). From a series of dose-response studies, we developed transfer functions predicting Pb uptake in C. sativa and we validated these functions with long-term Pb contaminated soils. The significant independent parameters were pore-water Pb²⁺ and dissolved Pb plus dissolved organic carbon (DOC). The observed RMSE for the Pb-DOC model and Pb²⁺ were 2.6 and 8.8, respectively. The Pb-DOC model tended to under-predict Pb, whilst Pb²⁺ tended to over-predict accumulation despite reasonable RMSE values. Further validation is needed in soils with higher pore-water Pb solubility.]]> Sat 24 Mar 2018 07:30:55 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:26437 Cucumis sativus L.) in spiked soils. Pore-water effective concentration (ECx, x=10%, 20% and 50% reduction) values were negatively related to pH, indicating lower Zn pore water concentration were needed to cause phytotoxicity at high pH soils. Total dissolved zinc (Zn_pw) and free zinc (Zn²⁺) in soil-pore water successfully described 78% and 80.3% of the variation in relative growth (%) in the full dataset. When the complete data set was used (10 soils), the estimated EC50_pw was 450 and 79.2µM for Zn_pw and Zn²⁺, respectively. Total added Zn, soil pore water pH (pH_pw) and dissolve organic carbon (DOC) were the best predictors of Znpw and Zn²⁺ in pore-water. The EC10 (total loading) values ranged from 179 to 5214mg/kg, depending on soil type. Only pH measurements in soil were related to ECx total Zn data. The strongest relationship to ECx overall was pH_ca, although pH_w and pH_pw were in general related to Zn ECx. Similarly, when a solution-only model was used to predict Zn in shoot, DOC was negatively related to Zn in shoot, indicating a reduction in uptake/ translocation of Zn from solution with increasing DOC.]]> Sat 24 Mar 2018 07:27:29 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:30028 Sat 24 Mar 2018 07:24:22 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:24101 Cucumis sativus L. (cucumber) and Triticum aestivum L. (wheat) and shoot end-points with a 4 week a pot study using cucumber only. Root elongation of cucumber was a substantially less sensitive indicator to As than data from the 4 weeks pot study. Effective concentrations (50%)(EC₅₀) from cucumber root elongation studies were overall 1.6 times higher than the 4 week shoot data. Cucumber was however considerably more sensitive to wheat. Given the large discrepancy in phytotoxicity end points for 7 soils, root elongation data for ecotoxicological assessment should be treated with some caution. Arsenic phytotoxicity was strongly related to the sorption constants of each of the seven soils in our study. Both root elongation and shoot data were related strongly to Freundlich partitioning constants (K_f) (L/kg). Wheat and cucumber root elongation had R² values 0.90 and 0.91 respectively, while cucumber shoot data was 0.79. The K_f values were related to soil pH and also EC₅₀ data and, thus, shows that As phytotoxicity in our study was primarily controlled by sorption reactions. The rate of As bioaccumulation to cucumber shoots depended heavily on the soil under consideration. Chlorophyll and carotenoid content of cucumber shoots increased with As content in 3 soils and decreased in other soils.]]> Sat 24 Mar 2018 07:11:45 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:24355 2+ was used to describe phytotoxicity of cucumber (Cucumis sativa L) in 10 contrasting soils at different soil Cu loadings. Both soil solution Cu (Cu_pw) and Cu²⁺ successfully described the response variable for all ten soils with R² values of 0.73 and 0.66, respectively. Separation of soils as acid and alkaline and fitting separately showed that there was a strongly significant fit for both log Cu²⁺ and log Cu_pw in acidic soils (R² = 0.92 and 0.86, respectively) but weakly significant fit for alkaline soils. The pCu EC₅₀ and EC₁₀ values in all acidic soils for cucumber were 5.83 (6.03–5.63) and 7.53 (8.27–7.00), respectively. In our dataset alkaline soils need to be treated individually. In addition, pCu could be predicted based on pH and total concentration alone. Despite only 12 weeks ‘ageing’ there was quantitative agreement between pCu model from this study and predicted pCu from Sauvé et al. This agreement from studies performed independently indicates that, at least in the case of Cu²⁺, the difference in an ageing period of ≥10 years appears minimal.]]> Sat 24 Mar 2018 07:10:17 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:47285 Mon 30 Oct 2023 17:10:01 AEDT ]]> https://ogma.newcastle.edu.au/vital/access/ /manager/Repository/uon:43453 Cucumis sativus L. (cucumber). The study showed that increasing ageing time of As from 0.25 to 5 years increased the EC₁₀ and EC₅₀ values by 4.0 and 1.76 fold, respectively. The dependence of ageing on soil properties was also examined, although only Freundlich sorption parameters were correlated to the ageing factor (r = 0.68, P = 0.028). Soils with high adsorption capacity also showed the greatest change in toxicity over 5 years. In addition, data was compiled from relevant literature to develop a model for As ecotoxicity. The combined model (n = 54) showed no relationship with pH but was correlated to the oxalate extractable iron content and %clay. Arsenate ecotoxicity (EC₅₀, mg/kg) in the multivariate model was related to oxalate iron content, %clay and ageing time. Thus, the results of this study have significant implications for risk assessment of long-term As contaminated soils.]]> Mon 19 Sep 2022 15:12:26 AEST ]]>