Perinatal dioxin exposure and later effects--a review

Negative effects of perinatal exposure to background levels of dioxins and PCBs in Europe and the USA have been documented. Four facets of development are reviewed in this paper: 1. Brain development and thyroid hormone metabolism. 2. Hepatic effects. 3. Hematopoietic system effects. 4. Lung function. Effects on IQ and behaviour have been documented in children on both sides of the Atlantic Ocean. Non-dioxin-like PCBs, measured in maternal and cord blood and current plasma samples have been implicated. Interference with thyroid hormone metabolism in the mother, in the foetus and in the newborn baby could be responsible for these effects on brain development. During early gestation the foetus is completely dependent on maternal thyroxine (T4). Lower T4 levels in the mother, caused by dioxins and PCBs, might negatively influence (early) brain development. It is plausible that the intrauterine dependency on maternal T4 and the high T4 need shortly after birth makes both these periods vulnerable for environmental influences. Effects of dioxin exposure on thyroid hormone metabolism have been described in the period shortly after birth. These effects are no longer found after two years of age indicating a transient effect. In animal studies, in utero exposure has led to effects on brain development due to abnormal induction of liver enzymes. This induction resulted in lower testosterone and estrogen levels, interfering with brain development in the vulnerable period of language development and the development of visuo-spatial abilities. In humans this developmental period occurs around the thirtieth week of pregnancy. Follow-up studies in puberty and adolescence of the different cohorts studied is necessary to evaluate these negative influences. Damaging effects on the liver found shortly after birth have proven to be transient. Effects on the haematopoietic system are clear immediately after birth, for instance on white blood cells and thrombocytes. An increase in middle ear infections (otitis media) in relation to current levels of PCBs at the age of 4 years was described in the Rotterdam study. Negative effects on lung function in the sense of increased obstruction was found after 8 years in relation to perinatal exposure to dioxins in the Zaandam study. This rather new finding might explain the sharp increase in lung problems in children in the Western world.     

Predictors of turnover amongst volunteers: A systematic review and meta-analysis

Volunteers represent a global workforce equivalent to 61 million full-time workers. A significant decline in volunteering has highlighted the urgency to better understand and address turnover amongst volunteers. To address this, we conducted a systematic review and meta-analysis of turnover amongst volunteers. We also examined whether staying or leaving has different predictors. The meta-analysis integrated and synthesized 117 studies, encompassing 1104 effect sizes across 55 335 volunteer workers, to identify and quantify relationships between turnover and the broad range of variables that have been examined in the volunteer work domain. Amongst the strongest predictors of volunteer turnover were attitudinal variables, in particular, job satisfaction (ρ = −.58), affective commitment (ρ = −.58), engagement (ρ = −.54) and organizational commitment (ρ = −.54). Contextual variables that showed the largest effects included communication (ρ = .62), organizational support (ρ = −.61) and the quality of the relationship between volunteers and their leader (leader-member exchange, ρ = −.55). We synthesize our findings into an integrative framework delineating the predictors of volunteer turnover. In doing so, we extend turnover research to consider non-remunerated work contexts and provide a basis for developing turnover theory that is responsive to the unique experience of volunteers.     

Networks,Agency and (De)stabilization: The Issue of Navigation on the River Wye,UK

This paper assesses the way in which an actor network presiding over the management of the River Wye has stabilized through accepting a particular view on the issue of navigation. The paper provides an account of how the network was challenged by a dissonant actor who, through reviving an old company, developed a counter network. It is argued that network stabilization is a form of consensus-building and it is contended that the way in which an issue is defined is crucial in terms of the successful enrolment of actors. The paper illustrates some of the conflicts and complexities encountered in resource planning, suggesting that research of this nature should trace actors back through time as well as through space if dynamics between actors involved in rural planning and management are to be effectively understood.     

Sustainable development in the mining industry: clarifying the corporate perspective

This paper examines sustainable development in the corporate mining context, and provides some guidelines for mining companies seeking to operate more sustainably. There is now a burgeoning literature that examines sustainable development in the context of minerals and mining, most of which is concerned with sustainability at global and national scales. What is often challenging to ascertain, however, from these numerous perspectives on sustainable mineral extraction, minerals and metals recycling, environmental management, and social performance, is how sustainable development applies to mining companies themselves, and what steps a mine must take in order to improve the sustainability of operations. Since mining processes have the potential to impact a diverse group of environmental entities, and are of interest to a wide range of stakeholder groups, there is ample opportunity for the industry to operate more sustainably. Specifically, with improved planning, implementation of sound environmental management tools and cleaner technologies, extended social responsibility to stakeholder groups, the formation of sustainability partnerships, and improved training, a mine can improve performance in both the environmental and socioeconomic arenas, and thus contribute enormously to sustainable development at the mine level.     

A Systematic Review of Public Attitudes,Perceptions and Behaviours Towards Production Diseases Associated with Farm Animal Welfare

Increased productivity may have negative impacts on farm animal welfare (FAW) in modern animal production systems. Efficiency gains in production are primarily thought to be due to the intensification of production, and this has been associated with an increased incidence of production diseases, which can negatively impact upon FAW. While there is a considerable body of research into consumer attitudes towards FAW, the extent to which this relates specifically to a reduction in production diseases in intensive systems, and whether the increased incidence of diseases represents a barrier to consumer acceptance of their increased use, requires further investigation. Therefore a systematic review of public attitudes towards FAW was conducted, with a specific focus on production diseases in intensive systems. Four databases were searched to identify relevant studies. A screening process, using a set of pre-determined inclusion criteria, identified 80 studies, with the strength of evidence and uncertainty assessed for each. A thematic analysis led to the identification of 6 overarching themes constructed from 15 subthemes. The results demonstrate that the public are concerned about FAW in modern production systems. Concern varied in relation to age, gender, education and familiarity with farming. Naturalness and humane treatment were central to what was considered good welfare. An evidence gap was highlighted in relation to attitudes towards specific production diseases, with no studies specifically addressing this. However, the prophylactic use of antibiotics was identified as a concern. A number of dissonance strategies were adopted by consumers to enable guilt free meat consumption.     

Formation of dioxins during exposure of pesticide formulations to sunlight

Chlorinated pesticides can contain impurities of dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), and their precursors, as a result of various manufacturing processes and conditions. As precursor formation of PCDD/Fs can also be mediated by ultraviolet light (UV), this study investigated whether PCDD/Fs are formed when currently used pesticides are exposed to natural sunlight. Formulations containing pentachloronitrobenzene (PCNB; n = 2) and 2,4-dichlorophenoxyacetic acid (2,4-D; n = 1) were exposed to sunlight in quartz tubes, and the concentration of 93 PCDD/F congeners were monitored over time. Considerable formation of PCDD/Fs was observed in both PCNB formulations (by up to 5600%, to a maximum concentration of 57 000 μg ∑PCDD/F kg⁻¹) as well as the 2,4-D formulation (by 3000%, to 140 μg ∑PCDD/F kg⁻¹). TEQ also increased by up to 980%, to a maximum concentration of 28 μg kg⁻¹ in PCNB, but did not change in the 2,4-D formulation. Assuming similar yields as observed in the present study as a worst case scenario the use of PCNB in Australia may result in the formation of 155 g TEQ annum⁻¹, contributed primarily by OCDD formation. This warrants detailed evaluations on the contemporary release of PCDD/Fs to the environment after the use of pesticides. Changes in congener profiles (including the ratio of PCDDs to PCDFs (DF ratio)) suggest that pesticide sources of PCDD/Fs after sunlight exposure may not be recognized based on matching source fingerprints established from manufacturing impurities. These changes also provide preliminary insights into the possible formation routes and types of precursors involved.     

Weak climatic control of stand-scale fire history during the late holocene

Forest fire occurrence is affected by multiple controls that operate at local to regional scales. At the spatial scale of forest stands, regional climatic controls may be obscured by local controls (e.g., stochastic ignitions, topography, and fuel loads), but the long-term role of such local controls is poorly understood. We report here stand-scale (<100 ha) fire histories of the past 5000 years based on the analysis of sediment charcoal at two lakes 11 km apart in southeastern British Columbia. The two lakes are today located in similar subalpine forests, and they likely have experienced the same late-Holocene climatic changes because of their close proximity. We evaluated two independent properties of fire history: (1) fire-interval distribution, a measure of the overall incidence of fire, and (2) fire synchroneity, a measure of the co-occurrence of fire (here, assessed at centennial to millennial time scales due to the resolution of sediment records). Fire-interval distributions differed between the sites prior to, but not after, 2500 yr before present. When the entire 5000-yr period is considered, no statistical synchrony between fire-episode dates existed between the two sites at any temporal scale, but for the last 2500 yr marginal levels of synchrony occurred at centennial scales. Each individual fire record exhibited little coherency with regional climate changes. In contrast, variations in the composite record (average of both sites) matched variations in climate evidenced by late-Holocene glacial advances. This was probably due to the increased sample size and spatial extent represented by the composite record (up to 200 ha) plus increased regional climatic variability over the last several millennia, which may have partially overridden local, non-climatic controls. We conclude that (1) over past millennia, neighboring stands with similar modern conditions may have experienced different fire intervals and asynchronous patterns in fire episodes, likely because local controls outweighed the synchronizing effect of climate; (2) the influence of climate on fire occurrence is more strongly expressed when climatic variability is relatively great; and (3) multiple records from a region are essential if climate-fire relations are to be reliably described.     

Safeguarding livelihoods or exacerbating poverty? Artisanal mining and formalization in West Africa

In recent years, policy mechanisms to support a formalized artisanal and small‐scale mining (ASM) sector in sub‐Saharan Africa have gained increasing currency. Proponents of formalization argue that most social and environmental problems associated with the sector stem from the fact that ASM is predominantly unregulated and operates outside the legal sphere. This paper critically examines recent efforts to formalize artisanal and small‐scale mining in West Africa, drawing upon recent fieldwork carried out in Sierra Leone, Ghana and Mali. In exploring the sector's livelihood dimensions, the analysis suggests that bringing unregulated, informal mining activities into the legal domain remains a considerable challenge. The paper concludes by confirming the urgent need to refocus formalization strategies on the main livelihood challenges and constraints of small‐scale miners themselves, if poverty is to be alleviated and more benefits are to accrue to depressed communities in mineral‐rich regions.     

Local Dirt, Global Dreams: mining investment and land use change in Arizona

A central problematic for researchers working at the interface of economic and environmental change is the development of research designs and methodologies that can satisfactorily link economic processes of global reach (such as direct investment) to environmental change at local and regional scales. This article reviews recent efforts to couple economic and environmental change and finds that relatively little effort has been made to use the direct investment process as a means of linking industrial restructuring to land use change. The article argues that direct investment, when conceptualised as a political-economic process involving the assemblage of a package of rights (to land, water, pollution permits etc), can be an effective vehicle for tracing through the impacts of industrial restructuring on local environments. To develop this analytical approach, an empirical case of mineral investment in the Gila Valley of eastern Arizona is presented. The case study identifies the acquisition of land and water rights as central strategic issues for mineral firms seeking to make investment, and traces through the impact of these acquisition strategies on existing patterns of land ownership and land use.