Bioavailability and metabolism of hexavalent chromium compounds †

Intratracheal instillation of ⁵¹CrCl₃ in anaesthetized rabbits resulted in partial absorption. In blood, the absorbed material was entirely confined to the plasma compartment. Only trace amounts were deposited in liver and kidney. By contrast, after similar application of Na, ⁵¹CrO₄ the bulk of blood radioactivity was present in red blood cells (RBC). Substantial deposition occurred in liver and kidneys. It is concluded that Cr(VI) may enter the body unreduced via the lung and is partially deposited in cells over a prolonged period of time.

Since chromium was accumulated in liver after administration of Cr(VI) we investigated the intracellular disposition of Cr(VI) in the isolated perfused liver. No significant sex differences in chromium distribution were observed. At the end of the experiments (1 h), 60% of the applied dose (312μg Cr/liver) was located in the cytosol, whilst 14% was in the mitochondria, 9% in the microsomal pellet and 2% was associated with the nuclei. Gel chromatography of the cytosolic compartment showed that the overwhelming part of chromium was eluted in fractions with an apparent molecular weight of 6,000 dalton. These fractions exhibited absorption maxima at 410nm and 548nm. It is concluded, that cytosolic reduction might be the main intracellular redox pathway for chromates. This view was confirmed by monitoring the reaction of Cr(VI) with GSH in vitro. GSH reduced Cr(VI) without further cofactors under formation of GSH‐chromium complexes, which possibly represent major intermediates in the metabolism of Cr(VI).     

Cadmium and chromium in human lung tissue in relation to smoking and lung cancer

The pulmonary Cd and Cr content was determined from 53 lung cancer patients operated for cancer and from 39 patients who died of non‐malignant diseases. The results were correlated with smoking habits, pulmonary emphysema and occupational history. Both the pulmonary Cd and Cr increased with the amount of smoking. In ex‐smokers the Cr content in lung tissue did not diminish with the time since stopping smoking, but the Cd did follow the half‐life of about 9 years. The pulmonary Cd, compared with smoking habits, behaved similarly in both the lung cancer and control patients, whereas Cr in the lung cancer patients could not be explained solely by smoking, but some of the cancer patients may have been occupationally exposed to Cr. Speciation was not studied.     

Learning in participatory environmental governance – its antecedents and effects. Findings from a case survey meta-analysis

ABSTRACT

Theory on participatory and collaborative governance maintains that learning is essential to achieve good environmental outcomes. Empirical research has mostly produced individual case studies, and reliable evidence on both antecedents and environmental outcomes of learning remains sparse. Given conceptual ambiguities in the literature, we define governance-related learning in a threefold way: learning as deliberation; as knowledge- and capacity-building; and as informing environmental outputs. We develop nine propositions that explain learning through factors characterizing governance process and context, and three propositions explaining environmental outcomes of learning. We test these propositions drawing on the ‘SCAPE’ database of 307 published case studies of environmental decision-making, using multiple regression models. Results show that learning in all three modes is explained to some extent by a combination of process- and context-related factors. Most factors matter for learning, but with stark differences across the three modes of learning, thus demonstrating the relevance of this differentiated approach. Learning modes build on one another: Deliberation is seen to explain both capacity building and informed outputs, while informed outputs are also explained by capacity building. Contrary to our expectations, none of the learning variables was found to significantly affect environmental outcomes when considered alongside the process- and context-related variables.     

Assessing the net atmospheric impacts of wood production and utilization

The main objective of the study was to calculate net atmospheric impacts for wood production and utilization in Finnish boreal forest conditions. Net atmospheric impacts were calculated by comparing net CO₂ exchanges of the wood production and utilization to the reference management regime. Net CO₂ exchanges were simulated with a life cycle assessment (LCA) tool for a Scots pine (Pinus sylvestris L.) stand (MT, Myrtillys-type) in central Finland (Joensuu region, 62°39 N, 29°37 E) over two consecutive rotation periods (100?+?100 years/200 years). Net atmospheric impacts were calculated both for sawn timber and pulpwood, and expressed in kgCO₂m^?3. According to the results, the production of pulp and sawn timber produced emissions of 0.20 and 0.59 kgCO₂m^?3 over the 200-year period, respectively, when the unmanagement regime was used as the reference management regime. When 50 % of the processing waste of timber was accounted as an instant emission to the atmosphere, the atmospheric impact increased to 0.55 kgCO₂m^?3 in pulpwood and to 1.27 kgCO₂m^?3 in sawn timber over the 200 year period. When turnover rates of sawn timber in the technosystem were decreased by 30 % and the share of energy use was decreased to 30 %, the atmospheric impact decreased by 17 % and 4 % for pulpwood and sawn timber, respectively, compared to the default wood degradation and energy use of 50 %. The utilized LCA approach provided an effective tool for approaching net atmospheric impacts originating from the ecosystem carbon (C) flows and variable wood utilization. Taking the ecosystem production and utilization of wood (i.e. degradation of technosystem C stock) into account, in terms of net CO₂ exchange, the mitigation possibilities of wood compared to other products can be accounted for more precisely in the future and C sequestration credited more specifically for a certain wood product.     

The acceptability of wind farms: the impact of public participation

The planning process for wind farm projects appears to be a complicated matter in many cases. Despite the positive attitude towards wind power in general, local wind farm projects often face strong opposition. The aim of this study is to shed more light on residents’ perceptions of participation in the planning process of wind farms. This study is based on interview data (N?=?22) and survey data (N?=?291) collected from residents living near two Finnish large-scale onshore wind farms built about 1.5 years before the data were collected. The results indicate that residents’ participation in the planning process was rather passive and the vast majority of the respondents perceived that they did not have an opportunity to participate. Quite interestingly, perceived participation in the planning process resulted in a decrease in acceptability in terms of perceived well-being. Furthermore, the results indicate that the need for participation does not expire after the planning process for a wind farm has concluded. Thus, project developers should be prepared to continue communication with residents after the planning phase.     

Heterogeneous preferences for recreation-oriented management in commercial forests: the role of citizens’ socioeconomic characteristics and recreational profiles

The management of forests for multiple benefits, such as recreational services alongside timber production, can greatly benefit from the knowledge of public preferences for management-related forest attributes. This paper investigates citizens’ recreational use and preferences for recreation-oriented management in the case of state-owned commercial forests in Finland using data from a choice experiment study. We focus on attributes related to the typical management practices applied to enhance recreation: scenic buffer zones along waters, game bird habitats, and the quality of scenery along hiking trails. Recreational use and its frequency were found to be related to citizens’ background and specific outdoor activities. The scenic buffer zones were the most important attribute to the citizens. While the recreation-enhancing practices were generally valued, respondent segments with distinct preferences were found. Preference heterogeneity was related to citizens’ socioeconomic characteristics and recreational profiles.     

Hydrolytic and ligninolytic enzyme activities in the Pb contaminated soil inoculated with litter-decomposing fungi

The impact of Pb contamination was tested to five hydrolytic (beta-glucosidase, beta-xylosidase, beta-cellobiosidase, alpha-glucosidase and sulphatase) and two ligninolytic (manganese peroxidase, MnP and laccase) enzyme activities in the humus layer in the forest soil. The ability of eight selected litter-degrading fungi to grow and produce extracellular enzymes in the heavily Pb (40 g Pb of kg ww soil(-1)) contaminated and non-contaminated soil in the non-sterile conditions was also studied. The Pb content in the test soil was close to that of the shooting range at H?lv?l? (37 g Pb of kg ww soil(-1)) in Southern Finland. The fungi were Agaricus bisporus, Agrocybe praecox, Gymnopus peronatus, Gymnopilus sapineus, Mycena galericulata, Gymnopilus luteofolius, Stropharia aeruginosa and Stropharia rugosoannulata. The Pb contamination (40 g Pb of kg ww soil(-1)) was deleterious to all five studied hydrolytic enzyme activities after five weeks of incubation. All five hydrolytic enzyme activities were significantly higher in the soil than in the extract of the soil indicating that a considerable part of enzymes were particle bound in the soils. Hydrolytic enzyme activities were higher in the non-contaminated soil than in the Pb contaminated soil. Fungal inocula increased the hydrolytic enzyme activities beta-cellobiosidase and beta-glucosidase in non-contaminated soils. All five hydrolytic enzyme activities were similar with fungi and without fungi in the Pb contaminated soil. This was in line that Pb contamination (40 g Pb of kg ww soil(-1)) depressed the growth of all fungi compared to those grown without Pb in the soil. Laccase and MnP activities were low in both Pb contaminated and non-contaminated soil cultures. MnP activities were higher in soil cultures containing Pb than without Pb. Our results showed that Pb in the shooting ranges decreased fungal growth and microbial functioning in the soil.