Transfer of Escherichia coli to water from drained and undrained grassland after grazing

The aim of this study was to determine the load of Escherichia coli transferred via drainage waters from drained and undrained pasture following a grazing period. Higher concentrations (ranging between 10(4) and 10(3) colony forming units [CFU] g(-1)) of E. coli persisted in soil for up to 60 d beyond the point where cattle were removed from the plots, but these eventually declined in the early months of spring to concentrations less than 10(2) CFU g(-1). The decline reflects the combined effect of cell depletion from the soil store through both wash-out and die-off of E. coli. No difference (P > 0.05) was observed in E. coli loads exported from drained and undrained plots. Similarly, no difference (P > 0.05) was observed in E. coli concentrations in drainage waters of mole drain flow and overland plus subsurface interflow. Intermittent periods of elevated discharge associated with storm events mobilized E. coli at higher concentrations (e.g., in excess of 400 CFU mL(-1)) than observed during low flow conditions (often <25 CFU mL(-1)). The combination of high discharge and cell concentrations resulted in the export of E. coli loads from drained and undrained plots exceeding 10(6) CFU L(-1) s(-1). The results highlight the potential for drained land to export E. coli loads comparable with those transferred from undrained pasture.     

Biodegradation of Dispersed Forties Crude and Alaskan North Slope Oils in Microcosms Under Simulated Marine Conditions

For oil spills in the open sea, operational experience has found that conventional response techniques, such as mechanical recovery, tend to remove only a small fraction of oil during major spills, a recent exception being the Mississippi River spill in Louisiana [Spill Sci. Technol. Bull. 7 (2002) 155]. By contrast, the use of dispersants can enable significant fractions of oil to be removed from the sea surface by dispersing the oil into the water column. It is thought that once dispersed the oil can biodegrade in the water column, although there is little information on the mechanism and rate of biodegradation. Two studies were undertaken on dispersion, microbial colonisation and biodegradation of Forties crude and Alaskan North Slope (ANS) oils under simulated marine conditions. The study using the Forties crude lasted 27 days and was carried out in conditions simulating estuarine and coastal conditions in waters around the UK (15 °C and in the presence of nutrients, 1 mg N-NO₃/l), while the ANS study simulated low temperature conditions typical of Prince William Sound (8 °C) and took place over 35 days. The results of both studies demonstrated microbial colonisation of oil droplets after 4 days, and the formation of neutrally buoyant clusters consisting of oil, bacteria, protozoa and nematodes. By day 16, the size of the clusters increased and they sank to the bottom of the microcosms, presumably because of a decrease in buoyancy due to oil biodegradation, however biodegradation of n-alkanes was confirmed only in the Forties study. No colonisation or biodegradation of oil was noted in the controls in which biological action was inhibited. Oil degrading bacteria proliferated in all biologically active microcosms. Without dispersant, the onset of colonisation was delayed, although microbial growth rates and population size in ANS were greater than observed with the Forties. This difference reflected the greater droplet number seen with ANS at 8 °C than with Forties crude at 15 °C. Although these studies differed by more than one variable, complicating comparison, the findings suggest that dispersion (natural or chemical) changes the impact of the oil on the marine environment, potentially having important implications for management of oil spills in relation to the policy of dispersant use in an oil spill event.     

Challenges for food system adaptation today and tomorrow

Global environmental change presents both old and new challenges. A far more systematic application of existing science in the entire food chain is essential to meet future food needs. While this is daunting enough in itself, new questions present themselves through changing food habits and global environmental change. The immediate challenge is to adapt plant, animal and food systems to changing temperature, nutrient and water conditions. To develop sustainable food systems in the long term, the paper discusses a set of considerations such as food demand response, resource efficiency, GHG emission limits and provisions to reduce vulnerability. Finally, some factors are presented to reframe the nature of food systems: multifunctionality, globalisation, food and fuel prices, consumer behaviour and state support to food production.     

From the Whitehorse Mining Initiative Towards Sustainable Mining: lessons learned

Much debate has taken place within the mineral policy community about whether or not meaningful progress has been made towards more sustainable practices. This paper investigates the changing approaches towards sustainable development undertaken by the Mining Association of Canada (MAC) over a period of approximately 20 years. The analysis begins in the early 1990s when MAC initiated the Whitehorse Mining Initiative (WMI) and concludes in 2010 when the association was operating under a strategy entitled Towards Sustainable Mining (TSM). The goal is to consider the nature of the learning that has taken place towards sustainability within the mineral industry using the case of a leading national mining association. The investigation was undertaken through a literature review as well as key informant interviews with stakeholders affected by the Canadian Mining Industry. Findings suggest that MAC’s approach to sustainable development has shifted from an ambitious and holistic partnership involving a range of stakeholders to a focused, member-specific agenda that addresses a few performance issues. The transition to TSM was based on lessons learned through working with the WMI and subsequent efforts. It reflects broader corporate tendencies to address social and ecological issues through corporate social responsibility initiatives. The implications of these trends suggest that voluntary initiatives in and of themselves should not be expected to replace the comprehensive regulatory responsibilities historically provided by government.     

Temperature limits trail following behaviour through pheromone decay in ants

In Mediterranean habitats, temperature affects both ant foraging behaviour and community structure. Many studies have shown that dominant species often forage at lower temperature than subordinates. Yet, the factors that constrain dominant species foraging activity in hot environments are still elusive. We used the dominant ant Tapinoma nigerrimum as a model species to test the hypothesis that high temperatures hinder trail following behaviour by accelerating pheromone degradation. First, field observations showed that high temperatures (> 30°C) reduce the foraging activity of T. nigerrimum independently of the daily and seasonal rhythms of this species. Second, we isolated the effect of high temperatures on pheromone trail efficacy from its effect on worker physiology. A marked substrate was heated during 10 min (five temperature treatments from 25°C to 60°C), cooled down to 25°C, and offered in a test choice to workers. At hot temperature treatments (>40°C), workers did not discriminate the previously marked substrate. High temperatures appeared therefore to accelerate pheromone degradation. Third, we assessed the pheromone decay dynamics by a mechanistic model fitted with Bayesian inference. The model predicted ant choice through the evolution of pheromone concentration on trails as a function of both temperature and time since pheromone deposition. Overall, our results highlighted that the effect of high temperatures on recruitment intensity was partly due to pheromone evaporation. In the Mediterranean ant communities, this might affect dominant species relying on chemical recruitment, more than subordinate ant species, less dependent on chemical communication and less sensitive to high temperatures.     

Adapting air quality management for a changing climate: Survey of local districts in California

Air quality can be affected by weather and thus is sensitive to a changing climate. Wildfire (influenced by weather), consecutive high temperature summer days, and other extreme events are projected to become more severe and frequent with climate change. These may create challenging conditions for managing air quality despite policy targets to reduce precursor and pollutant emissions. Although extreme events are becoming more intense and interest in climate adaptation is increasing among public health practitioners, little attention in scholarly literature and policy covers climate adaptation for air quality governance. Understanding the management and managers’ perspectives at the local level provides insight about the needs for climate adaptation, including their adaptation status, perspectives, responsibilities, and roles. This study explores local manager perspectives and experiences of managing air quality within a changing climate as one puzzle piece to understand the gap in climate adaptation within the air quality sector. A broader goal is to contribute to the discussion of developing a multi-jurisdictional vision for reducing the impacts of air quality in a changing climate. In 2016 local air quality district managers in California were invited to participate in an online survey of 39 questions focused on extreme event impacts on air quality. The questionnaire focused on present air quality threats and extreme event challenges, adaptation status and strategies, adaptive capacities, perceived barriers to adaptation, and jurisdictional responsibilities and roles. Over 85 percent of the 35 local air districts in California participated in the survey, which represents 80 percent of the state’s population. High awareness and knowledge of climate change among local managers indicates they are ready to adopt and take action on policies that would support climate adaptation, but barriers reported suggests they may need policies and adequate funding to take action and make necessary changes.

Implications: Downscaled global climate models project an increasing severity and frequency of extreme events. In the southwestern United States, these include wildfire, heat events, and dry periods, among others, all of which can place an extra burden on air quality managers and emitters to achieve air quality standards even as they reduce emissions. Despite climate change presenting increasing challenges to meet air quality standards, in the southwestern United States, policy and action to mitigate these impacts have been surprisingly absent. California presents a valuable case study on the topic because of its historic leadership in air quality management for the United States and also because of its initiatives in combating climate change. Yet still we found that adaptation has not been incorporated into air quality management thus far, but local managers seem sufficiently knowledgeable and willing.     

Linking planetary boundaries and ecosystem accounting,with an illustration for the Colombian Orinoco river basin

Economic development has increased pressures on natural resources during the last decades. The concept of planetary boundaries has been developed to propose limits on human activities based on earth processes and ecological thresholds. However, this concept was not developed to downscale planetary boundaries to sub-global level. The absence of boundaries at sub-global levels constrains the use of the concept in environmental governance and natural resource management, because decisions are typically taken at these levels. Decisions at the national level are currently supported, among others, by statistical frameworks in particular the System of National Accounts. However, statistical frameworks were not developed to compile environmental information, hindering environmental decision making. Our study examines if and how ecosystem accounting can be used in combination with the concept of planetary boundaries in guiding human activities at the level of a river basin. We assess the applicability of both frameworks for natural resource management in the Orinoco river basin, based on adaptive management components. Our analysis indicates that differences in the purpose of analysis, information provided, and methods constrain the potential integration of both frameworks. Nevertheless, the way both frameworks conceptualize the social system and the interactions between social and ecological systems can facilitate translating planetary boundaries into indicators considered in ecosystem accounting. The information recorded in national ecosystem accounts can support establishing ecological thresholds and, more fundamentally, to relate ecological thresholds to human impacts on ecosystem condition. Capitalizing on these synergies requires further exchange of experiences between the communities working on ecosystem accounting and planetary boundaries.

     

Quantitative monitoring of dermal and inhalation exposure to 1,6-hexamethylene diisocyanate monomer and oligomers

Respiratory sensitization and occupational asthma are associated with exposure to 1,6-hexamethylene diisocyanate (HDI) in both monomeric and oligomeric forms. The monomer and polymers of diisocyanates differ significantly in their rates of absorption into tissue and their toxicity, and hence may differ in their contribution to sensitization. We have developed and evaluated a liquid chromatography/mass spectrometry (LC-MS) method capable of quantifying HDI and its oligomers (uretidone, biuret, and isocyanurate) in air, tape-stripped skin, and paint samples collected in the automotive refinishing industry. To generate analytical standards, urea derivatives of HDI, biuret, and isocyanurate were synthesized by reaction with 1-(2-methoxyphenyl)piperazine and purified. The urea derivatives were shown to degrade on average by less than 2% per week at -20 degrees C over a 2 month period in occupational samples. The average recovery of HDI and its oligomers from tape was 100% and the limits of detection were 2 and 8 fmol microl(-1), respectively. Exposure assessments were performed on 13 automotive spray painters to evaluate the LC-MS method and the sampling methods under field conditions. Isocyanurate was the most abundant component measured in paint tasks, with median air and skin concentrations of 2.4 mg m(-3) and 4.6 microg mm(-3), respectively. Log-transformed concentrations of HDI (r = 0.79, p < 0.0001) and of isocyanurate (r = 0.71, p < 0.0001) in the skin of workers were correlated with the log-transformed product of air concentration and painting time. The other polyisocyanates were detected on skin for less than 25% of the paint tasks. This LC-MS method provides a valuable tool to investigate inhalation and dermal exposures to specific polyisocyanates and to explore relative differences in the exposure pathways.     

Maternal investment in mountain baboons and the hypothesis of reduced care

It has been argued that female mammals should terminate expensive forms of infant care earlier as habitat quality declines. More recently it has been shown that among a variety of mammalian species, early termination of care is also associated with highly favourable conditions. In this paper we present data on maternal investment decisions among baboons (Papio cynocephalus ursinus) inhabiting the Drakensberg Mountains of South Africa, and compare these with data from East African baboon studies. Mothers in the mountain habitat face a set of environmental conditions where the problem of resource allocation to offspring is expected to be particularly acute. We begin by using the model of Altmann (1980) of maternal time budgets to demonstrate that mountain baboon mothers experience greater perturbations to their activity budgets while suckling than do mothers in other populations. They also provide consistently greater levels of care to their infants and do so in the absence of any form of overt conflict over access to the nipple. Although this investment results in a relative lengthening of the interbirth interval (IBI), it is accompanied by relatively higher infant survival. We argue that factors that influence the maternal strategy adopted by mountain baboons include slow infant growth rates and a lack of predation in the habitat which influences probability of offspring survival beyond the immediate postnatal period. We suggest that both “care-dependent” sources of mortality (e.g. female reproductive condition, the amount of milk transferred to offspring) as well as “care independent” sources of mortality (e.g. predation, infectious disease) should be considered in studies of parental investment. Received: 26 May 1997 / Accepted after revision: 9 August 1997