Quantitative microbial risk assessment models for estimating the annual risk of enteric virus infection associated with consuming raw vegetables that have been overhead irrigated with nondisinfected secondary treated reclaimed water were constructed. We ran models for several different scenarios of crop type, viral concentration in effluent, and time since last irrigation event. The mean annual risk of infection was always less for cucumber than for broccoli, cabbage, or lettuce. Across the various crops, effluent qualities, and viral decay rates considered, the annual risk of infection ranged from 10 ؊3 to 10 ؊1 when reclaimed-water irrigation ceased 1 day before harvest and from 10 ؊9 to 10 ؊3 when it ceased 2 weeks before harvest. Two previously published decay coefficients were used to describe the die-off of viruses in the environment. For all combinations of crop type and effluent quality, application of the more aggressive decay coefficient led to annual risks of infection that satisfied the commonly propounded benchmark of <10 ؊4 , i.e., one infection or less per 10,000 people per year, providing that 14 days had elapsed since irrigation with reclaimed water. Conversely, this benchmark was not attained for any combination of crop and water quality when this withholding period was 1 day. The lower decay rate conferred markedly less protection, with broccoli and cucumber being the only crops satisfying the 10 ؊4 standard for all water qualities after a 14-day withholding period. Sensitivity analyses on the models revealed that in nearly all cases, variation in the amount of produce consumed had the most significant effect on the total uncertainty surrounding the estimate of annual infection risk. The models presented cover what would generally be considered to be worst-case scenarios: overhead irrigation and consumption of vegetables raw. Practices such as subsurface, furrow, or drip irrigation and postharvest washing/disinfection and food preparation could substantially lower risks and need to be considered in future models, particularly for developed nations where these extra risk reduction measures are more common.Agricultural irrigation with wastewater is known to occur in many parts of the world, although the extent of the practice is a debatable point (39). A recent estimate is that worldwide 20 million ha of irrigated agriculture uses raw, treated, and/or partially diluted wastewater (11). One of the most economically feasible agricultural uses of reclaimed water is the irrigation of high-value horticultural crops, which typically have high returns per volume of water invested in (5). But this practice has been approached with trepidation, owing primarily to concerns about risks to human health via contamination of food with pathogenic microorganisms (14, 45). It has been impossible to either allay or justify such concerns through traditional hypothesis testing science: infection rates are so low that the sample sizes needed for adequate statistical power render such studies impracticable. A more pr...

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In recent years, members of the Australian wine and grape industry have been encouraged to participate in a range of Environmental Management System (EMS)-type programs. These have been sponsored by a variety of stakeholders including government organisations, environmental non-government organisations, industry associations and large corporations. Collectively, these stakeholders have a diverse range of objectives they are seeking to address through the adoption of EMS by grape growers. These objectives range from natural resource management outcomes through to maintenance of market access and meeting investor expectations. However, these stakeholder objectives may not align to the individual needs of grape growers, nor to the drivers that may influence the adoption of an EMS by such individuals. To date, there has been variable success with voluntary adoption of EMS (or similar concepts) across viticulture regions throughout Australia. This paper seeks to clarify this variability based on an assessment of the needs and circumstances of various industry groups associated with EMS initiatives. A conceptual framework is proposed which categorises these particular needs according to different scales of influence (e.g. industry, region, business and individual). In addition, the drivers that operate at the individual grower level are further explored through a qualitative field study. This study has implications for the design and promotion of EMS programs for the wine and grape and other agricultural industries. It is clear that a ‘one size fits all’ approach will not meet the varying needs and objectives of all industry participants. Furthermore, grape growers may not perceive a need to change and, therefore, are yet to identify any benefits from voluntary adoption of an EMS. Alternative mechanisms such as market-based or regulatory instruments may need to be considered, dependent on the objectives that are sought.

Market research was conducted to develop an extension program targeting the specific irrigation management needs of growers in the stone and pome fruit industry within the Goulburn Valley, Victoria. The process of integrating market research with extension practice proved challenging, as it required the development of an extension program that was fundamentally different from what was originally envisaged. However, it was essential to achieve this integration in order to meet the original objectives for the extension program as set by the funding body. We found, in most cases, that the motivation for stone and pome fruit growers in the Goulburn Valley to change orchard irrigation management practices was not because they needed to save water, or to increase water use efficiency. Instead, growers were changing practices in order to save time irrigating, improve the scope for managerial flexibility in the orchard, or when redeveloping their orchard to a closer planting design. These findings suggest that growers in the Goulburn Valley are more likely to respond to an extension program consistent with these motivations rather than a program promoting water use efficiency.