Dioxins and polychlorinated biphenyls (PCDD/Fs and PCBs) in food from farms close to foot and mouth disease animal pyres

To control the outbreak of foot and mouth disease, which occurred in the UK in early 2001, a large number of farm animals were slaughtered. Where it was not possible to render or landfill the carcasses, they were destroyed by burning on open pyres, with wood, coal and other materials. Uncontrolled combustion such as this is known to produce small quantities of dioxins and an investigation was made into whether, as a result of the burning, there was an elevation in the concentrations of these compounds in food produced in the areas close to the pyres. With few exceptions, concentrations of PCDD/Fs and PCBs were within the expected ranges as predicted by reference data. No accumulation over time was evident from a repeat milk sampling exercise. Where elevated concentrations of PCDD/Fs and PCBs were found in chickens and eggs, they were in samples not destined for the food chain. Elevated levels in some samples of milk from Dumfries and Galloway were not found in earlier or later samples and may have been found as a result of a temporary feeding regime. Elevated concentrations in lamb from Carmarthenshire were from very young animals which would not have entered the food chain. There was no evidence of any significant increase in dietary exposure to PCDD/Fs and PCBs as a result of the FMD pyres.     

Long-term trends in organochlorine and mercury residues in some predatory birds in Britain

Residue levels of organochlorine pesticides (HEOD, DDE), polychlorinated biphenyls (PCBs) and mercury (Hg) in the livers of five predatory bird species were monitored in Britain over a 28-year (1963-1990) period. Of two raptor species, sparrowhawks contained higher levels of most chemicals than did kestrels. Among three fish-eaters, herons and kingfishers contained the highest levels of DDE and HEOD, while herons and great-crested grebes contained the highest levels of PCBs and mercury. Species differences were related partly to diet and habitat. In sparrowhawks and kestrels, residues of HEOD and DDE were higher in eastern, arable districts than elsewhere, especially in the 1960s and 1970s. In the fish-eaters, similar regional differences in residue levels were apparent in herons, especially in the 1970s, but not in the other species, for which samples were smaller. Over the 28 years, most species showed significant downward trends in HEOD, DDE and Hg levels, but only two fish-eaters showed significant declines in PCB levels. The downward trends in DDE and HEOD followed successive restrictions in the use of organochlorine pesticides, and were accompanied by recoveries in the populations and breeding success of affected species. Downward trends in mercury were associated with reductions in both agricultural use and industrial emissions.     

INVOLVING WATERSHED STAKEHOLDERS: AN ISSUE ATTRIBUTE APPROACH TO DETERMINE WILLINGNESS AND NEED1

ABSTRACT: The development of effective solutions for addressing nonpoint source pollution on a watershed basis often involves watershed stakeholders. However, success in engaging stakeholders in collaborative decision making processes varies, as watershed managers are faced with the challenges inherent to finding the right process for the decisions needed and in successfully engaging stakeholders in that process. Two characteristics that may provide guidance for determining the appropriateness of applying a collaborative process to a watershed problem are the need to collaborate and the willingness of stakeholders to engage in a collaborative decision making process. By examining seven attributes of the issues confronted by stakeholders in a collaborative process, the consequences of these attributes on the need for collaboration and stakeholders' willingness to engage can be estimated. The issue attributes include: level of uncertainty, balance of information, risk, time horizon of effects, urgency of decision, distribution of effects, and clarity of problem. The issue attribute model was applied to two collaborative decision making processes conducted by the same watershed stakeholder group in a North Carolina coastal watershed. Need and willingness to engage did not coincide for either issue; that is, stakeholders were more willing to engage on the issue that required less need for their involvement.     

Trophic specialisation of metazoan meiofauna at the Håkon Mosby Mud Volcano: fatty acid biomarker isotope evidence

We report the results of a detailed investigation on the trophoecology of two dominant meiofaunal species at the Håkon Mosby Mud Volcano (HMMV), a deep-sea cold methane-venting seep. Analyses of fatty acids (FAs) and their stable carbon isotopes were used to determine the importance of chemosynthetic nutritional pathways for the dominant copepod species (morphologically very similar to Tisbe wilsoni) inhabiting the volcano’s centre and the abundant nematode Halomonhystera disjuncta from the surrounding microbial mats. The strong dominance of bacterial biomarkers (16:1ω7c, 18:1ω7c and 16:1ω8c) coupled with their individual light carbon isotopes signatures (δ¹³C ranging from ?52 to ?81‰) and the lack of symbiotic relationships with prokaryotes (as revealed by molecular analyses and fluorescent in situ hybridisation) indicated that chemosynthetically derived carbon constitutes the main diet of both species. However, the copepod showed a stronger reliance on the utilisation of methanotrophic bacteria and contained polyunsaturated FAs of bacterial origin (20:5ω3 and 22:6ω3 with isotope signatures δ¹³C < ?80‰). Instead, the FA profiles of H. disjuncta suggested that sulphide-oxidising bacteria constituted the main diet of this nematode. Therefore, HMMV can be regarded as a persistent deep-sea cold seep, allowing a chemosynthesis-based trophic specialisation by the dominant meiofaunal species inhabiting its sediments. The present investigation, through the determination of the fatty acid profiles, provides the first evidence for trophic specialisation of meiofauna associated with sub-habitats within a cold seep.     

Uptake of cesium-137 and strontium-90 from contaminated soil by three plant species; application to phytoremediation

A field test was conducted to determine the ability of three plant species to extract 137Cs and 90Sr from contaminated soil. Redroot pigweed (Amaranthus retroflexus L.), Indian mustard [Brassica juncea (L.) Czern.], and tepary bean (Phaseolus acutifolius A. Gray) were planted in a series of spatially randomized cells in soil that was contaminated in the 1950s and 1960s. We examined the potential for phytoextraction of 90Sr and 137Cs by these three species. Concentration ratios (CR) for 137Cs for redroot pigweed, Indian mustard, and tepary bean were 2.58, 0.46, and 0.17, respectively. For 90Sr they were substantially higher: 6.5, 8.2, and 15.2, respectively. The greatest accumulation of both radionuclides was obtained with redroot pigweed, even though its CR for 90Sr was the lowest, because of its relatively large biomass. There was a linear relationship between the 137Cs concentration in plants and its concentration in soil only for redroot pigweed. Uptake of 90Sr exhibits no relationship to 90Sr concentrations in the soil. Estimates of time required for removal of 50% of the two contaminants, assuming two crops of redroot pigweed per year, are 7 yr for 90Sr and 18 yr for 137Cs.     

Human performance in polar environments

An overview of the physical, psychological, social, and coping aspects of living and working in polar regions is presented, assessing findings from both expedition teams and work groups. A personal narrative describing the experiences of a polar expeditioner is interspersed in relevant sections to provide a deeper understanding of the challenges of performing in an extreme environment. The application of findings from polar environments as an analog for space missions is discussed. We conclude that further research is needed on the integration of psychosocial and neurobehavioral adaptation. Furthermore, it is important to consider both the positive as well as negative features of living and working in polar and other extreme environments, and develop training strategies and countermeasure tools to optimize performance in these conditions.