An assessment of endocrine disrupting activity changes during wastewater treatment through the use of bioassays and chemical measurements.

The objective of this study was to assess the removal efficiencies of secondary wastewater treatment processes for compounds causing endocrine disrupting activity. The study used bioassays and chemical measurements, such as gas chromatography with mass spectrometry and enzyme immunosorbent assays. A total of seven full-scale water reclamation facilities using different unit operations and two pilot-scale membrane bioreactors were examined. Findings of this study imply that estrogenic disrupting activity in primary effluent is mainly caused by two steroidal hormones (17beta-estradiol and estriol) and, to a lesser extent, by synthetic chemicals, such as bisphenol A, 4-nonylphenol, and 4-tert-octylphenol. During secondary treatment, steroidal hormones were removed to a higher degree than nonylphenol and bisphenol A. The total estrogenic activity was removed by an average of 96%. The remaining concentrations of targeted steroids in secondary effluents, except for estriol, still had the potential to elicit a positive response in the human breast cell cancer assay. For the majority of facilities, the remaining activity was likely attributed to residual concentrations of two steroidal hormones (17beta-estradiol and estriol).     

Whose landcare? Observations on the role of 'community' in the Australian landcare programme

Australia's 'Landcare' programme is a community-based, participatory programme established by government, to tackle the problem of land degradation. It has been hailed by some as the world's most imaginative sustainable development policy. In light of the agreements reached at the Rio Earth Summit, particularly Agenda 21, the experience of established programmes such as Landcare may be useful to those beginning to grapple with the call for greater community involvement. This paper explores briefly the presentation and enactment of ideas of 'community' and 'ownership' in the Landcare programme and finds that, contrary to the rhetoric, community 'ownership' of Landcare is, in practice, ambiguous.     

The structure of the latero-frontal cirri on the gills of certain lamellibranch molluscs and their role in suspension feeding

Photomicroscopy and scanning electron microscopy were used to determine the fine structure of the latero-frontal cirri on the gills of three species of bivalve mollusc: Mytilus edulis Linn., Barnea candida (Linn.), and Petricola pholadiformis Lam. The component cilia are seen to branch off alternately along the length of each cirrus. Each of these free, lateral lengths of the cilia are separated from the next on their side by a mean distance of 0.6 m. They extend to a mean length of 2.7 m in M. edulis, the species described in detail. It is shown that a complete straining mesh can be formed over the gill ostium during normal filtering and the aperture of this mesh correlates well with the previously recorded filtering efficiency for Mytilus.     

Arrival timing and seasonal reproductive performance in a long-distance migratory landbird

The date when a landbird migrant arrives on its breeding grounds may have reproductive consequences. Generally, early arriving individuals begin breeding earlier and consequently experience greater seasonal reproductive performance. Here, we describe relationships between arrival timing and seasonal reproductive performance in the American redstart (Setophaga ruticilla), a long-distance passerine migrant, arriving at northerly breeding grounds in Michigans eastern Upper Peninsula. Evidence suggests that both males and females benefited from early arrival at the breeding grounds. Early males appeared to settle on higher quality territories and hatched nestlings sooner than later arrivals. Early females began their clutches early, produced heavier nestlings and possibly laid more eggs than later arrivals. Larger clutches and heavier offspring increase the likelihood of offspring recruiting into the breeding population. The findings of this study point to fitness consequences arising from when a bird arrives at its breeding grounds. These results also have implications for understanding how events occurring during spring migration influence reproductive performance as migratory delays likely influence arrival timing.Communicated by: W. Wiltschko     

Adsorption of crude oil on arctic terrain

Arctic terrain was divided into three layers, moss, detritus and clay, and each layer was contacted with Norman Wells crude oil. Chromatographic analysis of the crude oil extracts of the terrain layers showed that the adsorption capacity of the terrain increased with increasing organic content. The higher molecular weight n-alkanes were adsorbed to a greater extent than lower n-alkanes on the moss and detritus layers. Of the aromatics, p-xylene was adsorbed to a greater extent than benzene on all three layers of the terrain. Retention of crude oil components on Arctic terrain in the event of an oil spill would be in accord with these findings.     

Predicting bicycle helmet wearing intentions and behavior among adolescents

INTRODUCTION: Cycling accidents in Australia, especially those resulting in head injuries, are a substantive cause of death and disability; but despite legislation and evidence that helmets reduce the risk of head injury, few adolescents wear them. METHOD: This study employed a revised version of the Theory of Planned Behavior (TPB; [Ajzen, I. (1991). The theory of planned behavior. Organizational Behavior and Human Decision Processes, 50, 179-211]) to investigate the determinants of helmet use among a sample of adolescents. Participants in the initial data collection were 294 high school students in Year 8 and Year 11, with 266 completing a follow-up questionnaire measuring behavior over the previous two weeks. RESULTS: Social norms, perceptions of control, and past behavior significantly predicted intentions to use helmets and perceptions of control and past behavior predicted actual helmet use. CONCLUSIONS: Strengthening the routine of helmet use and building young people's confidence that they can overcome any perceived barriers to helmet use will improve adherence to helmet wearing behavior.