Michelle Graymore

Impacts of atrazine in aquatic ecosystems

A portion of all herbicides applied to forests, croplands, road sides, and gardens are inevitably lost to water bodies either directly through runoff or indirectly by leaching through groundwater into ephemeral streams and lakes. Once in the aquatic environment, herbicides may cause stress within aquatic communities and radically alter community structure. Atrazine is one of the most effective and inexpensive herbicides in the world and is consequently used more frequently than any other herbicide. Atrazine is frequently detected in aquatic waters, and has been known to affect reproduction of aquatic flora and fauna, which in turn impacts on the community structure as a whole. This paper presents a summary of the reported direct and indirect impacts of atrazine on aquatic organisms and community structure. The information can be used for developing improved management guidelines and legislation. It is concluded that a single universal maximum limit on the atrazine application in catchments, as suggested by many regulatory authorities, does not provide adequate protection of the aquatic environment. Rather, it is advocated that flexible limits on the application of atrazine be developed in line with the potential risk of contamination to surface and subsurface water and fragility of the aquatic environment.

Household water use behavior: an integrated model.

Water authorities are dealing with the challenge of ensuring that there is enough water to meet demand in the face of drought, population growth and predictions of reduced supply due to climate change. In order to develop effective household demand management programs, water managers need to understand the factors that influence household water use. Following an examination and re-analysis of current water consumption behavioral models we propose a new model for understanding household water consumption. We argue that trust plays a role in household water consumption, since people will not save water if they feel others are not minimizing their water use (inter-personal trust). Furthermore, people are less likely to save water if they do not trust the water authority (institutional trust). This paper proposes that to fully understand the factors involved in determining household water use the impact of trust on water consumption needs investigation.

Water savings or water efficiency? Water-use attitudes and behaviour in rural and regional areas

Drought conditions in southwest Victoria, as in other regions of Australia and around the world, have caused the need to reduce water consumption to ensure security of supply into the future. To develop effective water-saving behaviour change strategies, an understanding of peoples attitudes to the behaviour, including barriers stopping them from adopting the behaviour, is required. Thus, this paper explores the water-use behaviours and attitudes of rural and regional urban water users in southwest Victoria. A conceptual model of the factors impacting on water use of these users, including drivers and barriers to water saving, is developed. The factors that appear to impact on water-use behaviour not previously identified included the source of water supply (groundwater versus surface water), previous experience with water shortages and trust in the water authority and government. Also, a difference in the drivers for water saving was found, with farmers wanting to be ‘water efficient’ to keep their business viable and productive, while hobby farmers and residential users were ‘saving water’ for more altruistic reasons. These findings have implications for development of demand management strategies in this, and other, rural and regional areas. However, the conceptual model has to be tested to determine if it truly reflects factors influencing water-saving behaviour in rural and regional areas.

Environmental fate of pesticides used in Australian viticulture: Behaviour of dithianon and vinclozolin in the soils of the South Australian Riverland

Abstract The red calcareous earth soils of the South Australian Riverland produce more than one-third of the grapes used in Australian winemaking. As part of on-going investigations into pesticide transport in Australian vineyard soils, the movement of the fungicides dithianon and vinclozolin through such strongly alkaline soils was investigated. Small, undisturbed soil cores were extracted from the inter-row topsoil of a vineyard adjacent to the River Murray, approximately 10 km S.W. of Overland Corner, South Australia. The vines were grown in a deep (1 – 4 m) reddish brown, strongly alkaline, sandy loam with a low organic carbon content (1 – 2 %). Surface fluxes of pesticide were applied at the maximum recommended application rates to the surface of the cores, which were then irrigated, and pesticide residues in the leachate determined by HPLC. No leaching of either dithianon or vinclozolin occurred. Dithianon was immobilised in the top 2 cm of the soil. Dithianon concentrations were low ( 0 – 37 % applied dose) suggesting that rapid degradation of this compound occurs in these soils (63 – 100 % degradation in 10 days). Extremely low concentrations of vinclozolin were found throughout the soil core profiles (0.05 – 1.4 % applied dose) suggesting that this fungicide was somewhat mobile, but also that it too was unstable in such alkaline soils (> 98 % degradation in 10 days). These results suggest that the irrigated vineyard soils of this region are unlikely to be prone to leaching of dithianon or vinclozolin, and therefore that groundwater supplies in this area are unlikely to be at any significant risk of contamination through viticultural use of these compounds.

Assessing sustainability: a technical fix or a means of social learning?

The contextual nature of sustainability makes it extremely difficult to measure. Across the world each region has a specific environment and history that has shaped values and perceptions of the local community. In response, a wide range of tools has been developed that employ differing techniques to measure sustainability. These have a range of applications from global to site-specific scales. However, it is yet to be resolved whether assessments made using these tools reflect a technical focus with no close links to the knowledge and perceptions of stakeholders, community and management decisions, or whether the assessments reflect the knowledge and perceptions of local stakeholders and the community. In the southwest region of Victoria, Australia, a sustainability index called AIRS (An Index of Regional Sustainability) has recently been developed. This tool is based on indicators selected by stakeholders and considers relationships between the indicators. The aim of this paper is to report an ex-post evaluation of the AIRS sustainability assessment conducted at a subcatchment scale. The evaluation assesses AIRSs ability to assess regional sustainability and compares and contrasts the subcatchment assessments with the knowledge and perceptions of stakeholders and the community. A participatory approach that acknowledges key stakeholders was used for the evaluation process. Representatives from four stakeholder groups were interviewed to elicit their views of the AIRS assessment, its relevance, quality, applicability and priorities for future development. Strengths and weaknesses of AIRS are revealed and its contribution to social learning is highlighted.

PREFERENTIAL LEACHING OF NITRATE, CHLORIDE AND PHOSPHATE IN AN AUSTRALIAN CLAY SOIL

This paper investigates leaching of water and nutrients (NO/, Cl, PO/) from the unsaturated layer in an Australian soil using a multisegment percolation system (MPS). Large undisturbed soil cores were collected from a clay-based, basaltic plain, agricultural soil at Grassmere, 300 km west of Melbourne, Australia. Significant heterogeneity (or preferential flow) of effluent moisture and solutes was detected (one-way ANOVA, p < 0.001). Fifty percent of the applied nitrate and chloride leached from the soil core within three days after initial application. Hundred percent of the applied nitrate and chloride leached from the soil core within 8 days after application. These results indicate little incorporation into the soil matrix, and possible denitrification or mineralisation. In contrast, after 18 days, less than 1% of the total applied phosphates leached from the soil, indicating strong adsorption. Our experiments indicate considerable heterogeneity in water flow patterns and solute leaching on a small spatial scale. Very rapid transport of nitrate and chloride through the soil was evident, in comparison phosphate leaching was negligible. These results have important implications for the management of nutrient schedules in agricultural soils, particularly those located in the Western District of Victoria, Australia.

Environmental fate of pesticides used in Australian viticulture V. Behaviour of atrazine in the soils of the south Australian Riverland

The transport of the s‐triazine herbicide, atrazine, through the red, calcareous earth soils of the South Australian Riverland was investigated. Small, undisturbed soil cores were extracted from the inter‐row topsoil of a vineyard adjacent to the River Murray, approximately 10 km south‐west of Overland Corner, South Australia. The vines were grown in a deep (1–4 m) reddish brown, strongly alkaline, sandy loam with a low organic carbon content (<2%). Atrazine concentrations in the leachate were dependent on application rate and soil type. High application rates on subsoil gave high rates of leaching for a longer time compared to the same application rate on topsoil and/or lower application rates on either topsoil or subsoil. Overall, 37–65% of the applied atrazine was detected in the leachate from subsoil cores, 14–25% in topsoil core leachates. Small amounts of atrazine (< 10% of applied dose) were found only in the top 2 cm of the core profiles. The results suggest that this herbicide is somewhat mobile ...

Environmental fate of pesticides used in Australian viticulture ii: Behaviour of dithianon and vinclozolin in an acidic soil of the rutherglen region of Victoria, Australia

The movement of the fungicides dithianon and vinclozolin through small, undisturbed soil cores (of dimensions 15 × 15 × 15 cm) was investigated. The cores were extracted from the topsoil and underlying subsoil of a research station paddock approximately 10 km SE of Rutherglen, Victoria. The soil above the bedrock consisted of a thin (20 cm) layer of red‐brown, acidic surface soil with a moderate organic carbon content (1.2–4.1%), below which was yellow‐brown bleached clay containing substantial amounts of buckshot (iron rich nodules 3–8 mm in diameter). Surface fluxes of pesticide were applied at the maximum recommended application rates to the centre of the cores, which were then irrigated. Pesticides were extracted from the leachate and soil using solid phase extraction (SPE) and residues determined by HPLC. No dithianon was detected in any leachate. Dithianon was found immobilised in the top 2 cm of the cores (7–38% applied dose). Approximately 5% of the applied vinclozolin leached through the topsoil ...

Environmental fate of pesticides used in Australian viticulture IV. Aqueous stability of dithianon

Dithianon formulations are unstable in slightly basic aqueous solutions (pH 9, 20°C, t ½ = 5.6 h) but relatively stable in neutral or acidic solution (pH 4,20°C, t ½ = 6443 h). To ensure the efficacy of this fungicide it is important to prepare the spray mix fresh with neutral or slightly acidic water. Dithianon is unstable towards natural sunlight in the solid and aqueous phase, with half‐lives of approximately 68 and 42 days, respectively. Thermal hydrolysis does not seem to be the preferred degradation pathway when aqueous solutions are heated by the South Australian summer sun. The major aqueous phase photodegradation product has been identified as 2,3‐dihydro‐1,4‐dithiaanthraquinone. These results strongly suggest that should dithianon be accidentally released into basic Australian waters then it is likely to be rapidly chemically hydrolysed and pose little long term environmental threat. However, dithianon is only slowly chemically and photo‐lytically hydrolysed in neutral and acidic waters, and in ...

Are transition towns indicators of deinstitutionalisation of aspects of western culture

Transition initiatives in Australia, as elsewhere, have been mooted as a means of increasing community resilience to the threats posed by peak oil, climate change and economic uncertainty. Their emergence has attracted researchers to ask questions around their purpose, effectiveness and attraction for those who participate, as well as their likely future prospects in changing attitudes and habits in their respective communities and in society as a whole. This paper contributes to the broader understanding of transition initiatives in Australia by analysing the findings from a survey conducted amongst those involved in such initiatives within a deinstitutional theory framework. It is concluded that although the emergence of these initiatives are somewhat indicative of deinstitutionalisation, this is limited. In addition, the concepts and concerns on which they are based flow only slowly into the broader community.