Was monochloramine responsible for widespread lettuce crop failures at a major recycled water irrigation scheme?

In 2008, vegetable growers observed stunted lettuce plants showing signs of chlorosis and wilting. It was suspected that monochloramine in the recycled water used for irrigation, in combination with extreme environmental conditions (high irrigation water salinity and extreme heat), was responsible for these crop failures. A series of glasshouse studies was conducted to evaluate the impact of monochloramine concentration alone on iceberg lettuce seedlings, as well as in combination with high salinity and hot ambient temperatures. Monochloramine concentrations up to 9 and 15 mg L−1 Cl2 for continuous and initial irrigation only, respectively, did not affect the weight of iceberg lettuce heads (p > 0.05), while the combination of monochloramine (4–5 mg L−1 Cl2) and salinity (3,500 μS cm−1) did not significantly affect harvest measurements (p > 0.05). We therefore conclude that it is unlikely that monochloramine was responsible for the observed crop failures.

Workers’ compensation and mental health : examining the mental health impacts of involvement in the Victorian Work Cover system from the perspective of long-­term injured workers

The project aimed to explore long--term injured workers’ experiences and perceptions of their mental health as they progressed through the Victorian WorkCover process. The purpose of the project was to assist in understanding these factors in order to identify how workers might be better supported, and to identify changes that compensation authorities, employers and unions can make to reduce mental distress amongst injured workers. As a project based on workers’ accounts of their experiences, it aimed to provide a narrative basis for the development of supportive policy and practice to reduce mental distress amongst people who are clients of the WorkCover system. The project was a qualitative study based on fifteen in--depth interviews with people who had been injured at work and who had been off work for at least six months. The workers who took part in the study were recruited with the assistance of their trade unions, using an advertisement that was distributed via the unions’ regular communication channels. Workers were asked to tell their story of injury and recovery with a particular focus on how they felt and the factors that affected them, both positively and negatively. They were also asked what could or should be changed to support workers’ recovery and improve their experience of the WorkCover system. The workers who took part in the study came from a variety of industry sectors (education, textile and clothing manufacturing and meat industries) and different occupational categories (professional, trade/technical and manual). They included people whose primary injury was physical and those whose primary injury was psychosocial.

The influence of cover on nesting Red-capped Plovers: a trade-off between thermoregulation and predation risk?

 Some ground-nesting birds adopt a mixed strategy of nesting in the open, or under cover (e.g. vegetation). This may represent a trade-off between thermally favourable nest sites (covered) and those that enable the early detection and avoidance of predators (open). This study examined whether such a trade-off exists for Redcapped Plover Charadrius ruficapillus, whose eggs are preyed upon principally by Little Raven Corvus mellori. For real and artificial nests, nest temperatures under cover (real, 25.9 ± 0.1°C; false, 16.2 ± 0.5°C) were cooler than those in the open (real, 26.8 ± 0.1°C; false, 17.4 ± 0.9°C). Covered nests had more visual obstructions than open nests (covered, 65.5% ± 11.4%; open, 7.4% ± 2.8%) and a standardised measure of incubator escape distance, initiated by experimental human approaches, indicated incubators fled open nests at longer distances than for covered nests. Nests under cover showed a slightly (non-significant) higher probability of surviving one day (Daily Survival Rate [DSR] = 0.978) than those in the open (DSR = 0.950). For false nests containing model eggs, covered nests exhibited better survival to 10 days compared with open nests (20.4% vs. 4.7%). Thus, covered nests are associated with enhanced thermal environments and egg survival, but predators can approach the incubator more closely. Overall, the proposed trade-off between thermal and predation risks associated with nest sites appears to exist and explains the ongoing occurrence of nests in open and covered locations.

The control of rodent damage in Australian macadamia orchards by manipulation of adjacent non-crop habitats

 Habitat manipulation was used as a management strategy for the control of rodent (Rattus rattus) damage in Australian macadamia orchard systems. Large, temporally stable non-crop habitats were converted to highly modified grasslands. These sites were manipulated by removing all non-crop vegetation over 10 cm in height to a distance of approximately 20 m from the orchard. Regrowth was controlled by the application of herbicide. The total cost of the habitat manipulation was $AUD 292 per site. Manipulation resulted in a reduction in damage of 65% within the associated orchards. This reduction in rodent damage resulted in a saving of $AUD 980 per site. Therefore habitat manipulation was cost-effective and is a viable startegy for the control of rodent damage in Australian macadamia orchard systems.

Ex Libris - the book in contemporary art: cover image

Catalogue and exhibition essay for Ex Libris. Essay by Lisa Sullivan, curator Geelong Gallery. Catalogue cover image by Patrick Pound, detail from 'From Darkness to Light.

Cholinesterase Research Outreach Project (CROP): measuring cholinesterase activity and pesticide use in an agricultural community

BACKGROUND: Australian farmers and their workers are exposed to a wide variety of pesticides. Organophosphate (OP) insecticides are a widely used class of pesticide used for animal husbandry practices (Naphthalophos for sheep dipping, jetting and drench), crop production for pest control (Dimethoate) and in public health (Maldison for head lice). Acute poisonings with this class of insecticide are reported among agricultural workers and children around the globe, due to the inhibition of acetylcholinesterase (AChE). Less is known about chronic exposures. Regular monitoring of erythrocyte AChE will enable farmers to identify potential exposure to organophosphate insecticides and take action to reduce exposures and improve their health and safety practices. This study aims to assess and improve the integration of AChE monitoring into routine point of care health clinics, and provide farming and non-farming people with a link between their AChE activity and their household chemical and agrichemical use. METHODS/DESIGN: The research will target individuals who work on mixed farming enterprises and routinely using OPs (n = 50) and non-farmers (n = 30). Baseline data are collected regarding demographic, health conditions and behaviours, Kessler 10 (K10) scores, chemical use and personal protection. Baseline anthropometric measures include height, weight, hip and waist circumference, body fat analysis and, biochemical analysis of fasted total serum cholesterol, triglycerides, low-density cholesterol (LDL), high-density cholesterol (HDL) and blood glucose. Analysis of erythrocyte cholinesterase (EAChE) activity is also conducted using a finger prick test. Testing of EAChE is then repeated in all participants every 3 weeks for a maximum of three times over a period 10 weeks. Participants are provided with full feedback and counselling about their EAChE activity after each reading and a detailed summary provided to all participants at the completion of the study. Data will be analysed using repeated measures within a general linear model. DISCUSSION: This work will provide an evidence base and recommendations for the integration of EAChE monitoring into Australian rural health clinics, leading to research which will further quantify pesticide exposure both on the farm and in the home, highlighting the importance of sustaining and providing a safe work and home environment for farming communities. TRIAL REGISTRATION: ACTRN12613001256763.

Cover, not caging, influences chronic physiological stress in a ground-nesting bird

Predator exclosures ('nest cages') around nests are increasingly used to enhance hatching success of declining ground-nesting birds. However, such exclosures are contentious and have been suggested to have detrimental effects on the species which they aim to protect. This study examines whether exclosures increase physiological stress of incubating birds, a hitherto unrecognised and untested potential drawback of exclosures. Red-capped plover Charadrius ruficapillus hatching success was radically altered and significantly higher for nests with exclosures (96.2%) compared with those without (6.8%). Chronic physiological stress in parents (as measured by the heterophil/lymphocyte [H/L] ratio in blood) did not vary between nests with and without exclosures, or between the sexes. However the absence of vegetative cover at the nest site was associated with a 62.7% elevation in H/L ratio, indicating that incubating birds which place their nests in the open are subject to increased levels of chronic stress. The results from this study demonstrate the fundamental importance of predation for the nesting success of this species and confirm that chronic stress levels are not a detrimental side effect of exclosure use.