Cultivar substitution as a remediation strategy in radiocaesium and radiostrontium contaminated areas

Radioisotopes of caesium (Cs) and strontium (Sr) have been distributed in the environment due to weapons testing, nuclear power production and accidents at nuclear facilities. Radiocaesium and radiostrontium are of major concern in the medium to long term following accidental releases as they have high energies, long half lives (137Cs≈30 years; 90Sr≈29 years) and their easy assimilation into biological systems due to their similarity to the biologically important elements potassium (K) and calcium (Ca), respectively. Radio-caesium and -strontium are transferred to humans primarily via plant root uptake, and therefore minimising this uptake has been the focus of a number of remediation strategies, such as ploughing and fertiliser application. Species or cultivar substitution, where a species/cultivar that has higher uptake is replaced by a species/cultivar that has lower uptake, has been proposed as an effective and socially acceptable remediation strategy for contaminated agricultural land, but not enough is known about its efficacy for it to be recommended internationally. The aim of this thesis is to evaluate the potential of species or cultivar substitution as a remediation strategy for contaminated agricultural areas. Chapter 2 consists of meta-analysis of the available data (115 experiments) on the inter-cultivar variation in Cs and Sr accumulation by 27 plant species. Chapter 3 includes experiments conducted in the laboratory (UK) and two experiments in the field (Ukraine) investigating inter-cultivar variation in radiocaesium and radiostrontium accumulation in Brassica oleracea, and whether consistently lower-accumulating cultivars could be identified. Chapter 4 details analysis of samples from grass breeding experiments in Aberystwyth and Edinburgh (UK) from four forage grass species; hybrid ryegrass (Lolium perenne L. x Lolium multiflorum Lam.), L. perenne, L. multiflorum and Festuca arundinacea Shreb., and investigates inter-species and inter-cultivar variation in uptake of stable Cs and Sr. Hybrid ryegrass cultivars that were lower-accumulating in Cs and/or Sr were also identified. Chapter 5 compares the stable Cs and Sr uptake in six L. perenne and two F. arundinacea cultivars grown in Aberystwyth and Narodychi (Ukraine). Chapter 6 compares the performance in terms of yield and forage quality (elemental concentrations, digestibility and water soluble carbohydrate content) of six hybrid ryegrass cultivars and ten F. arundinacea cultivars identified as consistently lower-accumulating in Cs and/or Sr against the performance of two commercial hybrid ryegrass cultivars. The mean inter-cultivar variation in Cs and Sr was 1.8-fold and 2.0-fold, respectively when 27 plant species were studied. Thirty-five-fold variation in radiocaesium and 23-fold variation in radiostrontium was found between c. 70 Brassica oleracea cultivars. In two field experiments in Ukraine, five cultivars had consistently lower radiocaesium concentration ratios and two cultivars consistently lower radiostrontium concentration ratios. One cultivar had lower radiocaesium and radiostrontium concentration ratios. Festuca I arundinacea cultivars had lower Cs and Sr concentration ratios than cultivars of hybrid ryegrass, L. perenne and L. multiflorum. Three out of 17 hybrid ryegrass cultivars had consistently lower Cs concentration ratios, two cultivars consistently lower Sr and one consistently lower Cs and Sr. Despite differences in soil properties and environmental conditions, F. arundinacea cultivars grown in Aberystwyth and Narodychi accumulated less stable and radioactive Cs and Sr than L. perenne cultivars. One L. perenne cultivar also accumulated less Cs and Sr at both sites. Festuca arundinacea cultivars accumulated less Cs and Sr than commercial hybrid ryegrass cultivars, but also had up to 59% lower yield and a reduction of up to 19% in K accumulation, up to 46% in Ca accumulation, up to 7% in dry matter digestibility and up to 17% in water soluble carbohydrate content. Selecting lower-accumulating cultivars was found to reduce Cs and Sr accumulation less, but with a smaller yield penalty and a smaller reduction in digestibility and water soluble carbohydrate content. It is concluded that species and cultivar substitution could be an effective remediation strategy in contaminated agricultural land provided implications for yield and quality are considered

Cultivar substitution as a remediation strategy in radiocaesium and radiostrontium contaminated areas

Radioisotopes of caesium (Cs) and strontium (Sr) have been distributed in the environment due to weapons testing, nuclear power production and accidents at nuclear facilities. Radiocaesium and radiostrontium are of major concern in the medium to long term following accidental releases as they have high energies, long half lives (137Cs≈30 years; 90Sr≈29 years) and their easy assimilation into biological systems due to their similarity to the biologically important elements potassium (K) and calcium (Ca), respectively. Radio-caesium and -strontium are transferred to humans primarily via plant root uptake, and therefore minimising this uptake has been the focus of a number of remediation strategies, such as ploughing and fertiliser application. Species or cultivar substitution, where a species/cultivar that has higher uptake is replaced by a species/cultivar that has lower uptake, has been proposed as an effective and socially acceptable remediation strategy for contaminated agricultural land, but not enough is known about its efficacy for it to be recommended internationally. The aim of this thesis is to evaluate the potential of species or cultivar substitution as a remediation strategy for contaminated agricultural areas. Chapter 2 consists of meta-analysis of the available data (115 experiments) on the inter-cultivar variation in Cs and Sr accumulation by 27 plant species. Chapter 3 includes experiments conducted in the laboratory (UK) and two experiments in the field (Ukraine) investigating inter-cultivar variation in radiocaesium and radiostrontium accumulation in Brassica oleracea, and whether consistently lower-accumulating cultivars could be identified. Chapter 4 details analysis of samples from grass breeding experiments in Aberystwyth and Edinburgh (UK) from four forage grass species; hybrid ryegrass (Lolium perenne L. x Lolium multiflorum Lam.), L. perenne, L.multiflorum and Festuca arundinacea Shreb., and investigates inter-species and inter-cultivar variation in uptake of stable Cs and Sr. Hybrid ryegrass cultivars that were lower-accumulating in Cs and/or Sr were also identified. Chapter 5 compares the stable Cs and Sr uptake in six L. perenne and two F. arundinacea cultivars grown in Aberystwyth and Narodychi (Ukraine). Chapter 6 compares the performance in terms of yield and forage quality (elemental concentrations, digestibility and water soluble carbohydrate content) of six hybrid ryegrass cultivars and ten F. arundinacea cultivars identified as consistently lower-accumulating in Cs and/or Sr against the performance of two commercial hybrid ryegrass cultivars. The mean inter-cultivar variation in Cs and Sr was 1.8-fold and 2.0-fold,respectively when 27 plant species were studied. Thirty-five-fold variation in radiocaesium and 23-fold variation in radiostrontium was found between c.70 Brassica oleracea cultivars. In two field experiments in Ukraine, five cultivars had consistently lower radiocaesium concentration ratios and two cultivars consistently lower radiostrontium concentration ratios. One cultivar had lower radiocaesium and radiostrontium concentration ratios. Festuca arundinacea cultivars had lower Cs and Sr concentration ratios than cultivars of hybrid ryegrass, L. perenne and L. multiflorum. Three out of 17 hybrid ryegrass cultivars had consistently lower Cs concentration ratios, two cultivars consistently lower Sr and one consistently lower Cs and Sr. Despite differences in soil properties and environmental conditions, F. arundinacea cultivars grown in Aberystwyth and Narodychi accumulated less stable and radioactive Cs and Sr than L. perenne cultivars. One L. perenne cultivar also accumulated less Cs and Sr at both sites. F. arundinacea cultivars accumulated less Cs and Sr than commercial hybrid ryegrass cultivars, but alsohad up to 59% lower yield and a reduction of up to 19% in K accumulation, up to 46% in Ca accumulation, up to 7% in dry matter digestibility and up to 17% in water soluble carbohydrate content. Selecting lower accumulating cultivars was found to reduce Cs and Sr accumulation less, but with a smaller yield penalty and a smaller reduction in digestibility and water soluble carbohydrate content. It is concluded that species and cultivar substitution could be an effective remediation strategy in contaminated agricultural land provided implications for yield and quality are considered

Consumer‑driven strategies towards a resilient and sustainable food system following the COVID‑19 pandemic in Australia

Background: The COVID-19 pandemic and associated public health restrictions temporarily disrupted food supply chains around the world and changed the way people shopped for food, highlighting issues with food systems resilience and sustainability. The aim of this study was to explore consumer-driven strategies towards a more resilient and sustainable food system in Australia, learning from experiences during the beginning of the COVID-19 pandemic. Methods: During May–June 2020, a cross-sectional, online survey was conducted in Tasmania, Australia in a non-random sample of adults aged 18 years and over. The survey collected demographic data and posted the open-ended question: “How could Tasmania’s food system be better prepared for a disaster in the future?” Descriptive statistics were used to analyse the demographic data and thematic analysis was employed to analyse the qualitative data. Results: Survey respondents (n = 698) were predominantly female (79%), over 55 years of age (48%), university educated (70%) and living with dependents (45%). Seven key themes were identified: (i) balance food exports with local needs; (ii) strengthen local food systems; (iii) increase consumer awareness of food supply chains; (iv) build collaboration and connection in the food system; (v) embed clear contingency arrangements; (vi) support community capacity building and individual self-sufficiency; and (vii) the food system coped well. Conclusions: The consumer-driven strategies identified indicate multiple opportunities to increase resilience and sustainability in the food system to avoid future supply disruptions. Our findings indicate that considerable popular support for more resilient, local and sustainable food systems may be emerging from the COVID-19 pandemic

Prevalence and socio-demographic predictors of food insecurity in Australia during the COVID-19 pandemic

The COVID-19 pandemic has exacerbated economic vulnerabilities and disrupted the Australian food supply, with potential implications for food insecurity. This study aims to describe the prevalence and socio-demographic associations of food insecurity in Tasmania, Australia, during the COVID-19 pandemic. A cross-sectional survey (deployed late May to early June 2020) incorporated the U.S. Household Food Security Survey Module: Six-Item Short Form, and fifteen demographic and COVID-related income questions. Survey data (n = 1170) were analyzed using univariate and multivariate binary logistic regression. The prevalence of food insecurity was 26%. The adjusted odds of food insecurity were higher among respondents with a disability, from a rural area, and living with dependents. Increasing age, a university education, and income above $80,000/year were protective against food insecurity. Food insecurity more than doubled with a loss of household income above 25% (Adjusted Odds Ratio (AOR): 2.02; 95% CI: 1.11, 3.71; p = 0.022), and the odds further increased with loss of income above 75% (AOR: 7.14; 95% CI: 2.01, 24.83; p = 0.002). Our results suggest that the prevalence of food insecurity may have increased during the COVID-19 pandemic, particularly among economically vulnerable households and people who lost income. Policies that support disadvantaged households and ensure adequate employment opportunities are important to support Australians throughout and post the COVID-19 pandemic

The problem-solving processes of writers and readers. Occasional Paper No.7

While young children\u27s problem-solving models are not as elaborate as those of older students, they share an important belief, namely, that writing and reading are fundamentally purposeful acts of communication. Focusing on the interpretation of process, in particular on writing and reading as forms of problem-solving that are shaped by communicative purpose, three sets of vignettes show students at different stages of schooling as they write and read. The first set illustrates the nature of problem-solving in skilled reading and writing processes that are held as goals for college students. The second set of vignettes places these processes in context by considering some of the factors that influence students\u27 problem-solving as they write and read in response to typical class assignments. The third section explores the problem-solving skills that young students--children learning to write and read and adolescents expanding their writing and reading abilities--bring to their school assignments. It is critical that strategies such as summarization and self-questioning not become disconnected from the larger communicative, meaning-construction process. The critical question is how to sustain and further develop the potential evident in the problem-solving of young writers and readers. Flexibly structured opportunities for teachers and students to exchange views about both their own and professional texts provide the student with context for cultivating a deeper understanding of writing and reading as purposeful acts of communication and to transform the contexts in which writing and reading occur

Forage grasses with lower uptake of casesium and strontium could provide 'safer' crops for radiologically contaminated areas

Substitution of a species or cultivar with higher uptake of an element by one with lower uptake has been proposed as a remediation strategy following accidental releases of radioactivity. However, despite the importance of pasture systems for radiological dose, species/cultivar substitution has not been thoroughly investigated for forage grasses. 397 cultivars from four forage grass species; hybrid ryegrass (Lolium perenne L. x Lolium multiflorum Lam.), perennial ryegrass (Lolium perenne L.), Italian ryegrass (Lolium multiflorum Lam.) and tall fescue (Festuca arundinacea Shreb.); were sampled from 19 field-based breeding experiments in Aberystwyth and Edinburgh (UK) in spring 2013 and analysed for caesium (Cs) and strontium (Sr) concentrations. In order to calculate concentration ratios (CRs; the concentration of an element in a plant in relation to the concentration in the soil), soils from the experiments were also analysed to calculate extractable concentrations of Cs and Sr. To test if cultivars have consistently low Cs and Sr concentration ratios, 17 hybrid ryegrass cultivars were sampled from both sites again in summer 2013 and spring and summer 2014. Tall fescue cultivars had lower Cs and Sr CRs than the other species. Three of the selected 17 hybrid ryegrass cultivars had consistently low Cs CRs, two had consistently low Sr CRs and one had consistently low Cs and Sr CRs. Cultivar substitution could reduce Cs CRs by up to 14-fold and Sr CRs by 4-fold in hybrid ryegrass. The identification of species and cultivars with consistently low CRs suggests that species or cultivar substitution could be an effective remediation strategy for contaminated areas

The new normal for food insecurity? : a repeated cross-sectional survey over 1 year during the COVID-19 pandemic in Australia

Background: Food insecurity during the COVID-19 pandemic has been impacted by necessary public health restrictions. Tasmania, an island state south of the Australian mainland, recorded no community transmission of COVID-19 between May 2020 to November 2021 due to strong border restrictions. This study aimed to determine the changes in prevalence and sociodemographic predictors of food insecurity throughout the COVID-19 pandemic in Tasmania, Australia. Methods: In May 2020 (survey 1: during lockdown), September 2020 (survey 2: eased restrictions) and May 2021 (survey 3: 1-year post-lockdown), cross-sectional, online surveys using convenience sampling methods determined food insecurity in Tasmanian adults using the USDA Household Food Security Survey Module: Six-Item Short Form, in addition to key sociodemographic questions. Crude and age-adjusted prevalence of food insecurity was calculated, and binary logistic regression determined at-risk groups and changes in prevalence over time. Results: The age-adjusted prevalence of food insecurity was 27.9% during lockdown (n = 1168), 19.5% when restrictions had eased (n = 1097) and 22.6% 1-year post-lockdown (n = 1100). Young adults, Aboriginal and/or Torres Strait Islander people, individuals with disabilities, families with dependents and temporary residents were at highest risk across all time points. Conclusions: The prevalence of food insecurity was higher than pre-pandemic levels across all three time points. Our results indicate the potential long-term impacts of the COVID-19 pandemic on food security in Australia, where despite easing social distancing restrictions and a lack of COVID-19 transmission, the prevalence of food insecurity reduced, but did not recover to pre-pandemic levels 1-year following a lockdown

Definitions, sources and self-reported consumption of regionally grown fruits and vegetables in two regions of Australia

Regional food systems are complex networks, with numerous retail sources that underpin a local economy. However, evidence is limited regarding how consumers define, identify, and source regionally grown fresh fruits and vegetables (RGFFV). A cross-sectional study was conducted in Tasmania (TAS) and South Western Australia (SWA) to compare how RGFFV are defined, identified and sourced by consumers, including self-reported consumption of selected RGFFV. Survey data were analyzed using the Chi-square test and t-tests. Results (TAS n = 120, SWA n = 123) identified that consumers had mixed perceptions of how RGFFV are defined, including produce sold at farmers markets, or grown within their region (TAS/SWA). RGFFV were commonly identified using product labelling (55% TAS, 69% SWA; p \u3e 0.05). Respondents reported frequently shopping for RGFFV at major supermarkets, with more TAS respondents shopping weekly in comparison to SWA respondents (67% vs. 38%; p \u3c 0.001). Supermarkets offered convenience and consumers enjoyed the experience of farmers’ markets, especially in TAS (42%) in comparison to SWA (21%; p = 0.012). The major RGFFV consumed were root vegetables and apples/pears, but consumers were frequently unsure about the produce’s provenance. Our findings indicate multiple opportunities to improve consumption of fresh, regional produce in TAS and SWA, which may positively impact regional economic growth and community health. © 2020 by the authors. Licensee MDPI, Basel, Switzerland

Australian consumer perceptions of regionally grown fruits and vegetables: Importance, enablers, and barriers

Fresh fruits and vegetables are a cornerstone of a balanced diet; their consumption has health, environmental, ethical, and economic implications. This pilot study aimed to: (i) measure fruit and vegetable consumption; (ii) understand consumer perceptions of the perceived importance of regionally grown fresh fruit and vegetables (RGFFV); and (iii) identify the barriers and enablers of access and consumption of RGFFV. The study took place in Tasmania (TAS) and South Western Australia (SWA). A 54-item survey included questions relating to purchasing and consumption patterns; barriers and enablers related to access and consumption of RGFFV; and sociodemographic information. Survey data were analyzed using Chi-square test and binary logistic regression. A total of n = 120 TAS and n = 123 SWA adult respondents participated. SWA respondents had higher intakes of fruit (p \u3c 0.001) and vegetables (p \u3c 0.001). Almost all respondents (97%) rated purchasing of RGFFV as important. Top enablers included produce freshness (97%), and to financially support local farmers (94%) and the local community (91%). Barriers included limited seasonal availability of the produce (26%), the belief that RGFFV were expensive (12%) and food budgetary constraints (10%). Recommendations include broader marketing and labelling of seasonal RGFFV; increasing ‘buy local’ campaigns; consumer information about how RGFFV benefits producers and communities; and pricing produce according to quality

A reconnaissance survey of farmers’ awareness of hypomagnesaemic tetany in UK cattle and sheep farms

Hypomagnesaemic tetany (HypoMgT) in ruminants is a physiological disorder caused by inadequate intake or impaired absorption of magnesium (Mg) in the gut. If it is not detected and treated in time, HypoMgT can cause the death of the affected animal. A semi-structured questionnaire survey was conducted from July 2016–2017 to assess farmers’ awareness of HypoMgT in cattle and sheep in the UK. The questionnaire was distributed to farmers at farm business events and agricultural shows, and through a collaborative group of independent veterinary practices to their clients. Farmers were asked about (i) the incidence of presumed HypoMgT (PHT); (ii) their strategies to treat or prevent HypoMgT; (iii) mineral tests on animals, forage and soil, and (iv) farm enterprise type. A total of 285 responses were received from 82 cattle, 157 mixed cattle and sheep, and 46 sheep farmers, of whom 39% reported HypoMgT in their livestock, affecting 1–30 animals. Treatment and/or prevention against HypoMgT was reported by 96% respondents with PHT and 79% of those without. Mineral tests on animal, forage, and soil was conducted by 24%, 53%, and 66% of the respondents, respectively, regardless of PHT. There was a highly significant association between the use of interventions to tackle HypoMgT and the incidence of PHT (p < 0.01). The top three treatment/prevention strategies used were reported as being free access supplementation (149), in feed supplementation (59) and direct to animal treatments (drenches, boluses and injections) (45) although these did vary by farm type. Although some (9) reported using Mg-lime, no other pasture management interventions were reported (e.g., Mg-fertilisation or sward composition). Generally, the results indicate that UK farmers are aware of the risks of HypoMgT. A more integrated soil-forage-animal assessment may improve the effectiveness of tackling HypoMgT and help highlight the root causes of the problem