Mineralogical characteristics and transformations during long-term operation of a zerovalent iron reactive barrier

Design and operation of Fe0 permeable reactive barriers (PRBs) can be improved by understanding the long-term mineralogical transformations that occur within PRBs. Changes in mineral precipitates, cementation, and corrosion of Fe0 filings within an in situ pilot-scale PRB were examined after the first 30 months of operation and compared with results of a previous study of the PRB conducted 15 months earlier using X-ray diffraction and scanning electron microscopy employing energy dispersive X-ray and backscatter electron analyses. Iron (oxy)hydroxides, aragonite, and maghemite and/or magnetite occurred throughout the cores collected 30 mo after installation. Goethite, lepidocrocite, mackinawite, aragonite, calcite, and siderite were associated with oxidized and cemented areas, while green rusts were detected in more reduced zones. Basic differences from our last detailed investigation include (i) mackinawite crystallized from amorphous FeS, (ii) aragonite transformed into calcite, (iii) akaganeite transformed to goethite and lepidocrocite, (iv) iron (oxy)hydroxides and calcium and iron carbonate minerals increased, (v) cementation was greater in the more recent study, and (vi) oxidation, corrosion, and disintegration of Fe0 filings were greater, especially in cemented areas, in the more recent study. If the degree of corrosion and cementation that was observed from 15 to 30 mo after installation continues, certain portions of the PRB (i.e., up-gradient entrance of the ground water to the Fe0 section of the PRB) may last less than five more years, thus reducing the effectiveness of the PRB to mitigate contaminants.     

Age differences in safety attitudes and safety performance in Hong Kong construction workers

PROBLEM: Safety in the construction industry is a major issue in Hong Kong, representing about 46% of all occupational injuries in 1998. This study explored linear and curvilinear relations between age and safety performance (accident rates and occupational injuries), as well as safety attitudes, in construction workers in Hong Kong. METHOD: A Chinese version of the Safety Attitude Questionnaire (SAQ by Donald & Canter) was developed and administered to a sample of Chinese construction workers (N=374, 366 males, 8 females) from 27 construction sites. RESULTS: Accident rates were not related to age. Occupational injuries were related to age in a curvilinear manner, with injuries at first increasing with age, then decreasing. Two safety attitude scales were related to age with older workers exhibiting more positive attitudes to safety. If age and tenure are controlled, some attitude scales are predictors of safety performance. IMPACT ON INDUSTRY: Management/supervisors, team leaders, and workers are all responsible for safety, and any negative bias toward older construction workers is unfounded.     

Business excellence through resource efficiency (betre): An evaluation of the UKs highest recruiting, facilitated self-help waste minimisation project

The business excellence through resource efficiency (betre) project aimed to increase awareness of the benefits of waste minimisation for SMEs in West Sussex, South East England. The programme was run by the West Sussex Sustainable Business Partnership, a collaboration of all West Sussex Local Authorities, the Environment Agency and EcoSys (a service provider). Betre provided a range of free business support and advice over an 18-month period including; workshops, newsletters, audits, grants and a technical Helpline. Information on environmental compliance and Best Practice for waste minimisation, recycling, energy and water efficiency was disseminated. All activities were linked with the UK government's Best Practice programmes. Although company recruitment was initially slow, betre was ultimately extremely successful at attracting companies to join; with 308 recruited. This is probably the most successful recruitment to a project, of this type, in the UK to date. Over half of the business members became actively involved and attended training events or had environmental audits. There were over 200 improvement actions identified by 64 of the participating companies. These resulted in estimated cost savings of at least £215 000 per annum. In addition, actions taken to prevent pollution and ensure compliance with environmental legislation have the potential to save businesses a further £204 000 in possible penalties. The environmental impact of the project has been significant, with reductions identified in waste (1437 tonnes), water (62 933 m³) and energy (15 million kW h—equivalent to 668 tonnes CO₂). In addition to actions with directly measurable results, betre has stimulated long-term benefits by addressing pollution prevention and compliance, through the formulation of environmental policies and from the adoption of Environmental Management Systems. One of the key learning points is that it may have been better to devote less time to running training events and instead to have diverted this time to increased business support, mainly through audits. To capitalise on this success, a new project is being planned to disseminate Best Practice.     

Sustainability in cattle production systems

Cattle production has the potential of being an important component of sustainable agriculture globally. The ability to transform feed not suitable for humans into high-quality food will be of great importance in the long-term for feeding a growing population. Other aspects such as preservation of landscape values and maintenance of rural communities are highly appreciated values, especially in the industrialized part of the world.To exploit the sustainable potential of cattle production systems, problems of pollution (such as ozone destruction, acid rain, and nitrate leaching) and of health and welfare, which are associated with cattle production, are critically reviewed. The possibilities of integrating cattle production with other types of production are evaluated. Cattle can be used for single purposes such as dairy, beef, and draught, but dairy cows can also be used for restricted suckling combining dairy and beef production. In addition a mixture of species makes grazing more efficient, and a combination of cattle and mixed cropping can increase resource efficiency.The possibilities of using organic cattle production systems as prototypes of sustainable cattle production systems are explored. The effects of production constraints which are applied in organic farming systems are studied. The redirection of values and activities in agriculture is a challenge to cattle production research and to traditional research methodologies.     

Biodegradable municipal waste (BMW) management strategy in Ireland: A comparison with some key issues in the BMW strategy being adopted in England

Due to increasing pressure from the European Union to meet recycling and recovery targets, (e.g. the packaging waste, waste electronic equipment and landfill directives), both the Irish and England's governments’ policy on waste management is changing to meet these pressures, with major emphasis upon the management of biodegradable municipal waste (BMW). In particular, the EU landfill directive requires reductions in the rate of biodegradable waste going to landfill to 35% by 2016. The objective of this paper is to examine how Ireland plans to meet this challenge and to compare the Irish strategy to that being adopted in England. The approach in England is driven by a clear understanding that the practice in the late 1990s was unlikely to ensure compliance with EU targets by the set dates. England has therefore developed a discrete, programme (Waste Implementation Programme) to drive a new approach, based on rigorous science and international best practice, which includes a Demonstrator Programme for new technologies. The dynamic, high cost, large scale programme in England stands in sharp contrast to that for Ireland and only future, detailed analysis of outcomes will be able to evaluate the cost effectiveness of each.     

Prey capture by Pisaster brevispinus (Asteroidea: Echinodermata) on soft substrate

Observations on the subtidal seastar Pisaster brevispinus (Stimpson) indicate that this predator can extend the central tube feet into sand-mud substrate for a distance roughly equal to the radius of the seastar. Field and laboratory evidence demonstrates the use of the elongated tube feet by the asteroid for the capture of burrowed prey items. A relationship between predator size and the size of juveniles of the deep-burrowing clam Tresus nuttallii taken as prey is a product of the ability of larger seastars to extend the tube feet further into the substrate and capture deeper prey. The role of P. brevispinus as an important subtidal predator along the Pacific Coast of North America is discussed.     

Impacts of pesticides in a Central California estuary

Recent and past studies have documented the prevalence of pyrethroid and organophosphate pesticides in urban and agricultural watersheds in California. While toxic concentrations of these pesticides have been found in freshwater systems, there has been little research into their impacts in marine receiving waters. Our study investigated pesticide impacts in the Santa Maria River estuary, which provides critical habitat to numerous aquatic, terrestrial, and avian species on the central California coast. Runoff from irrigated agriculture constitutes a significant portion of Santa Maria River flow during most of the year, and a number of studies have documented pesticide occurrence and biological impacts in this watershed. Our study extended into the Santa Maria watershed coastal zone and measured pesticide concentrations throughout the estuary, including the water column and sediments. Biological effects were measured at the organism and community levels. Results of this study suggest the Santa Maria River estuary is impacted by current-use pesticides. The majority of water samples were highly toxic to invertebrates (Ceriodaphnia dubia and Hyalella azteca), and chemistry evidence suggests toxicity was associated with the organophosphate pesticide chlorpyrifos, pyrethroid pesticides, or mixtures of both classes of pesticides. A high percentage of sediment samples were also toxic in this estuary, and sediment toxicity occurred when mixtures of chlorpyrifos and pyrethroid pesticides exceeded established toxicity thresholds. Based on a Relative Benthic Index, Santa Maria estuary stations where benthic macroinvertebrate communities were assessed were degraded. Impacts in the Santa Maria River estuary were likely due to the proximity of this system to Orcutt Creek, the tributary which accounts for most of the flow to the lower Santa Maria River. Water and sediment samples from Orcutt Creek were highly toxic to invertebrates due to mixtures of the same pesticides measured in the estuary. This study suggests that the same pyrethroid and organophosphate pesticides that have been shown to cause water and sediment toxicity in urban and agriculture water bodies throughout California, have the potential to affect estuarine habitats. The results establish baseline data in the Santa Maria River estuary to allow evaluation of ecosystem improvement as management initiatives to reduce pesticide runoff are implemented in this watershed.     

Retrospective assessment of dryland soil stability in relation to grazing and climate change

Accelerated soil erosion is an aspect of dryland degradation that is affected by repeated intense drought events and land management activities such as commercial livestock grazing. A soil stability index (SSI) that detects the erosion status and susceptibility of a landscape at the pixel level, i.e., stable, erosional, or depositional pixels, was derived from the spectral properties of an archived time series (from 1972 to 1997) of Landsat satellite data of a commercial ranch in northeastern Utah. The SSI was retrospectively validated with contemporary field measures of soil organic matter and erosion status that was surveyed by US federal land management agencies. Catastrophe theory provided the conceptual framework for retrospective assessment of the impact of commercial grazing and soil water availability on the SSI. The overall SSI trend was from an eroding landscape in the early drier 1970s towards stable conditions in the wetter mid-1980s and late 1990s. The landscape catastrophically shifted towards an extreme eroding state that was coincident with the “The Great North American Drought of 1988”. Periods of landscape stability and trajectories toward stability were coincident with extremely wet El Niño events. Commercial grazing had less correlation with soil stability than drought conditions. However, the landscape became more susceptible to erosion events under multiple droughts and grazing. Land managers now have nearly a year warning of El Niño and La Niña events and can adjust their management decisions according to predicted landscape erosion conditions.