Metallophyte status of violets of the section Melanium

Violets from metal-enriched soils have controversially been described as both heavy-metal accumulators and excluders in the literature. The present study solves the issue for violets of the section Melanium (zinc violets, Viola lutea ssp. calaminaria and V. lutea ssp. westfalica; hartsease or wild pansy, Viola tricolor; and mountain pansy, V. lutea). The aims were to determine the concentrations of heavy metals in the soil and in the roots and shoots of field-collected plants, to evaluate the potential impact of colonisation by arbuscular mycorrhizal fungi on heavy-metal concentrations in the plant tissues, and to quantitatively define the localisation of the elements in root cross-sections. When these violets grow in low-metal soils, higher concentrations of the heavy metals were found in the roots and shoots than in the soil, whereas the opposite was seen in samples from high-metal soils. Under all field conditions examined, the roots of all of these species were colonised by arbuscular mycorrhizal fungi. However, V. tricolor was marginally colonised when the concentrations of Zn and P were higher in the soil. Determination of the spatial distribution of the elements in root cross-sections of these violets indicates tissue-specific deposition of elements within the vascular tissue, the cortex, and the rhizodermis. These data indicate that violets of the section Melanium are heavy-metal excluders.     

Future land use and land cover in Southern Amazonia and resulting greenhouse gas emissions from agricultural soils

Regional Environmental Change - The calculation of robust estimates of future greenhouse gas emissions due to agriculture is essential to support the framing of the Brazilian climate change...     

Assessing the Transactional Nature of Wilderness Experiences: Construct Validation of the Wilderness-Hassles Appraisal Scale

Concerns over the increasing popularity of wilderness recreation have resulted in attempts to determine the amount of use that different areas can tolerate without adverse affects to the resource. Early attempts to establish recreational carrying capacities focused on managers' assessments of biophysical impacts. The perceptions of wilderness visitors, however, are now considered integral to capacity decisions. This study used a stress appraisal framework to understand wilderness visitors' perceptions of on-site conditions. It was based on the premise that negative appraisals of wilderness conditions produce stress and that individual perceptions vary based on personal and situational characteristics. The purpose of the study was to assess the validity of a wilderness-hassles appraisal scale by testing hypothesized relationships between experience-use history (EUH), place attachment, and stress appraisal. Data collection occurred through a postal survey of hikers (n = 385) contacted in the High Peaks and Pemigewasset Wilderness Areas during the summer of 2004. An exploratory factor analysis indicated that stress appraisal is a multi-dimensional construct. Validity testing procedures were restricted to those dimensions that were consistent between study areas and provided partial support for the hassles scale. As hypothesized, EUH did not influence perceptions of wilderness conditions. Place attachment, on the other hand, was positively correlated with stressful appraisals of social and managerial conditions. Although Kruskall Wallis tests revealed significant differences in visitors' perceptions of managerial conditions between study sites, perceptions of social conditions did not vary significantly. Implications for management and recommendations for further refinement of the wilderness hassles construct are discussed.     

Concentrations of polybrominated diphenyl ethers, organochlorine compounds and nitro musks in mother's milk from Germany (Bavaria)

The aim of this study was to determine a new spectrum of substances that will be selected for future breast milk monitoring in Bavaria, Germany. Up to now, the analysis of breast milk in Bavaria was limited to selected organochlorine pesticides (OCP) and polychlorinated biphenyls (PCB). Information on background levels of toxicologically interesting substances, such as dioxins and dioxin-like polychlorinated biphenyls (dl-PCB) or on flame retardants, such as polybrominated diphenyl ethers (PBDE) are very limited or not available for Bavaria. We present here levels on OCP, some nitro musks, indicator PCB, polychlorinated dibenzo-p-dioxins (PCDD), polychlorinated dibenzofurans (PCDF) and dl-PCB concentrations in breast milk collected at 12 weeks post-partum of 43 primiparous mothers living in Bavaria. The average concentrations of PCDD, PCDF and dl-PCB were 4.98, 4.93 and 9.92 pg WHO-TEQ g(-1) lipid, respectively. The mean contribution of PCDD, PCDF, non-ortho and mono-ortho PCB to the total WHO-TEQ is consistently about 25% each. Furthermore the concentration on PBDE in breast milk at two sampling points, 12 weeks and 16 weeks after delivery, were determined. Overall, 19 PBDE congeners were analysed, however the level of 12 PBDE congeners were below the limit of detection. BDE-153 and BDE-47 were the predominant congeners accounting for about 66% of the total PBDE. The means of the total concentrations of PBDE (five congeners) at the first and second sampling point were 1.90 and 2.03 ng g(-1) lipid, respectively. Based on our results the overall concentrations of the analysed substances in milk samples from Bavaria are consistent with the levels of breast milk samples of other European countries reflecting the low background body burden of these compounds.