Concentration of Organochlorine Pollutants in Surface Waters of the Central European Biosphere Reserve Krivoklatsko (8 pp)

Background, Aim and Scope The article is focused on dioxin, furan, PCB and organochlorine pesticide monitoring in the surface waters of the Central European, protected natural reserve Krivoklatsko, under the UNESCO programme Man and Biosphere. Persistent compounds are presently transported via different means throughout the entire world. This contamination varies significantly between sites. This raises the question of what constitutes the naturally occurring background levels of POPs in natural, unpolluted areas, but which are close to industrialised regions. Information of real background POP contamination can be of high value for risk assessment management of those sites evidently polluted and for the defining of de-contamination limits. Preserved areas should not be seen as isolated regions in which the impacts of human activities and natural factors are either unexpected or overlooked. Every ambient region, even those protected by a law or other means, are still closely connected to neighbouring human developed and impacted areas, and are therefore subject to this anthropogenic contamination. These areas adjacent to natural reserves are sources of diverse substances, via entry of air, water, soil and/or biota. After an extended period of industrial activities, organochlorine pollutants, even those emitted in trace concentrations have reached detectable levels. For future research and for the assessment of environmental changes, present levels of contamination would be of high importance. This work publishes data of the contamination with organochlorine pollutants of this natural region, where biodiversity and ecological functions are of the highest order. Materials and Methods: Semipermeable membrane devices (SPMDs) were utilised as the sampling system. SPMDs were deployed in two small creeks and one water reservoir selected in the central part of the Krivoklatsko Natural Reserve, where it could be expected that any possible contamination by POPs would be lowest. The exposed SPMDs were analysed both for chemical contents of POPs and for toxicity properties. The chemical analyses of dibenzo-dioxins, dibenzo-furans, PCBs and OCPs were analysed by GC/MS/MS on GCQ or PolarisQ (Thermoquest). Toxicity bioassays were performed on the alga Desmodesmus subspicatus, bacteria Vibrio fischeri and crustacean Daphnia magna. All toxicity data were expressed as the effective volume Vtox. Vtox is a toxicity parameter, the determination of which is independent of SPMD deployment time and pre-treatment dilution (unlike, for example, the EC50 of the SPMD extract). Results: The following chemical parameters were monitored: 1) tetra, penta, hexa and hepta dibenzo-p-dioxins and furans; 2) all those detectable from tri- through deca-polychloriated biphenyls (PCBs) and 3) a group of organochlorine pesticides: hexachlorobenzene and isomers of hexachlorocyclohexane, DDE, DDD and DDT. The concentrations of dioxins and furans on the assessed sites varied from under detection levels up to 7 pg.l-1; PCBs were detected in a sum concentration up to 2.8 ng.l-1; and organochlorine pesticides up to 346 pg.l-1. The responses of bioassays used were very low, with the values obtained for Vtox being under 0.03 l/d. Discussion: Toxicity testing showed no toxicity responses, demonstrating that the system used is in coherence with the ecological status of the assessed sites. Values of Vtox were under the critical value – showing no toxicity. The PCA of chemical analysis data and toxicity responses resulted in no correlations between these two groups of parameters. This demonstrated that the present level of contamination has had no direct adverse effects on the biota. Conclusions: The concentration values of six EPA-listed, toxic dioxins and sums of tetra-hepta dioxins; nine EPA toxic dibenzofurans and the sums of tetra-hepta bibenzofurans are presented together with all tri-deka PCBs and organochlorine pesticides (alfa-, beta-, gama-, delta-HCH, HCB, opDDE, ppDDE, opDDD, ppDDD, opDDT, ppDDT). These values represent possible current regional natural background values of these substances monitored within the Central European region, with no recorded adverse effects on the freshwater ecosystem (up until the present time). Recommendations and Perspectives: Assessment of dioxins, furans and other organochlorine compounds within natural reserves can be important for the monitoring of human-induced impacts on preserved areas. No systematic monitoring of these substances in areas not directly affected by industry has generally been realised. There is a paucity of data of the presence of any of these substances within natural regions. Further monitoring of contamination of both soil and biota by dioxins and furans in preserve regions is needed and can be used for future monitoring of man-made activities and/or accidents. Semipermeable membrane devices proved to be a very good sampling system for the monitoring of trace concentrations of ambient organochlorine compounds. Toxicity evaluation using the Vtox concept demonstrated that those localities assessed expressed no toxicity.     

Ethnobotanical skills and clearance of tropical rain forest for agriculture: a case study in the lowlands of Bolivia

Indigenous peoples are often considered potential allies in the conservation of biological diversity. Here we assess whether ethnobotanical skills of indigenous people contribute to a reduction in the clearance of tropical rain forest. We measured ethnobotanical skills of male household heads and area of rain forest cleared for agriculture among 128 households of Tsimane', a native Amazonian group in Bolivia. We used multivariate regressions to estimate the relation between ethnobotanical skills and area of rain forest cleared while controlling for schooling, health status, number of plots cleared, adults in household, and village of residency. We found that when the ethnobotanical skills of the male household head were doubled, the amount of tropical rain forest cleared per household was reduced by 25%. The association was stronger when the area of old-growth forest cleared was used as the dependent variable than when the area cleared from fallow forest was used as the dependent variable. People who use the forest for subsistence might place a higher value on standing forest than people who do not use it, and thus they may be more reluctant to cut down the forest.     

Urban water demand and climate change

This paper presents a methodology for improved understanding of options for managing urban water demands under the uncertainties associated with climate change. It combines a sensitivity analysis of water supply with forecasts of water demand and examines how conservation efforts may offset deficits which result from climate change. It presents a case study of Nassau County, New York State, USA, that concludes that deficits projected for warmer climate scenarios can probably be alleviated by increased conservation. For scenarios of decreased precipitation, more extreme measures (eg rationing) may be necessary, illustrating the prudence of considering climate change in planning studies for communities which already experience water supply problems.     

(137)Cs and (90)Sr uptake by sunflower cultivated under hydroponic conditions

The (90)Sr and (137)Cs uptake by the plant Helianthus annuus L. was studied during cultivation in a hydroponic medium. The accumulation of radioactivity in plants was measured after 2, 4, 8, 16 and 32 days of cultivation. About 12% of (137)Cs and 20% of (90)Sr accumulated during the experiments. We did not find any differences between the uptake of radioactive and stable caesium and strontium isotopes. Radioactivity distribution within the plant was determined by autoradiography. (137)Cs was present mainly in nodal segments, leaf veins and young leaves. High activity of (90)Sr was localized in leaf veins, stem, central root and stomata. The influence of stable elements or analogues on the transfer behaviour was investigated. The percentage of non-active caesium and strontium concentration in plants decreased with the increasing initial concentration of Cs or Sr in the medium. The percentage of (90)Sr activity in plants decreased with increasing initial activity of the nuclide in the medium, but the activity of (137)Cs in plants increased. The influence of K(+) and NH(4)(+) on the uptake of (137)Cs and the influence of Ca(2+) on the uptake of (90)Sr was tested. The highest accumulation of (137)Cs (24-27% of the initial activity of (137)Cs) was found in the presence of 10 mM potassium and 12 mM ammonium ions. Accumulation of about 22% of initial activity of (90)Sr was determined in plants grown on the medium with 8 mM calcium ions.     

Satellite-based decadal change assessments of pan-Arctic environments

Remote sensing can advance the work of the Circumpolar Biodiversity Monitoring Program through monitoring of satellite-derived terrestrial and marine physical and ecological variables. Standardized data facilitate an unbiased comparison across variables and environments. Using MODIS standard products of land surface temperature, percent snow covered area, NDVI, EVI, phenology, burned area, marine chlorophyll, CDOM, sea surface temperature, and marine primary productivity, significant trends were observed in almost all variables between 2000 and 2017. Analysis of seasonal data revealed significant breakpoints in temporal trends. Within the terrestrial environment, data showed significant increasing trends in land surface temperature and NDVI. In the marine environment, significant increasing trends were detected in primary productivity. Significantly earlier onset of green up date was observed in bioclimate subzones C&E and longer end of growing season in B&E. Terrestrial and marine parameters showed similar rates of change with unidirectional change in terrestrial and significant directional and magnitude shifts in marine.     

Substrate-dependent bacterivory by intertidal benthic copepods

The trophic importance of bacteria to harpacticoid copepods in intertidal areas remains poorly understood, and so do the mechanisms of bacterial feeding. It is, for instance, unclear whether harpacticoids directly target bacterial cells or merely co-ingest them with substrates to which bacterial cells may be attached. Here, we investigate bacterial uptake and substrate requirement for four mud intertidal species (Microarthridion littorale, Platychelipus littoralis, Delavalia palustris and Nannopus palustris) by means of ¹³C-labeled bacteria and biomarker fatty acids (FA). Bacterial uptake strongly depended on grazing on a primary food source but bacterial ingestion rates were low, and no clear indication of copepods directly targeting bacteria was found. Delavalia was the only species that accumulated bacteria-derived FA and gained in polyunsaturated FA (PUFA) probably through bioconversion of bacteria-derived FA. In general, however, our results suggest that bacteria represent a relatively minor and low-quality food for intertidal harpacticoid copepods.     

A proactive approach to human error detection and identification in aviation and air traffic control

In recent years, there has been a realization that total elimination of human error may be difficult to achieve. A further reduction of accidents will require a better understanding of how practitioners manage their errors in ways that consequences are contained or mitigated. With this goal in mind, the present study has set out to propose a framework of cognitive strategies in error detection that would make human performance resilient to changes in work demands. The literature regarded error detection as a spontaneous process that occurs either while an action is executed (action-based detection) or after action feedback (outcome-based detection). To help practitioners maintain a state of mindfulness and introspection, this study proposes several cognitive strategies such as, rehearsing tasks for future execution, bringing into conscious attention routine tasks, seeing how trajectories change over time, and cross-checking data for reliability. Two further detection mechanisms are proposed at the situation assessment and planning stages of performance. Awareness-based detection may include revising a model of the situation, finding hidden assumptions, and testing the plausibility of assumptions. Planning-based detection addresses issues such as, identifying uncertainties in a plan, thinking out possible errors, and deciding when and how often to review task progress. Finally, several attitudinal factors and team factors are presented that affect the processes of error detection and identification. The cognitive strategies in error detection together with the attitudinal and team factors constitute a framework for designing the content of error management training.     

Study of the spontaneous ignition of stoichiometric tetrafluoroethylene–air mixtures at elevated pressures

The Ignition Temperature (IT) of stoichiometric tetrafluoroethylene–air mixtures on hot walls was determined in a 3-dm³-reactor. Tests at elevated pressure conditions were performed, namely at 5, 15 and 25 bar(a), showing a decrease of the IT with the initial pressure. Furthermore, the measured ignition temperatures of stoichiometric tetrafluoroethylene–air mixtures were lower than the ignition temperatures required for the decomposition pure tetrafluoroethylene (Minimum Ignition Temperature of Decomposition, MITD) reported in previous works.Equations from the Semenov thermal explosion theory on spontaneous ignition were used to identify approximate combustion kinetics of tetrafluoroethylene from the experimental results. The determined kinetics was used for the prediction of the IT of stoichiometric tetrafluoroethylene-air by simplified calculation methods. A very good agreement with the experimental results was observed.     

Evaluating the impact of HIA on urban reconstruction decision-making. Who manages whose risks?

Practitioners and academic researchers increasingly look to evaluation of health impact assessment (HIA) to improve its practice, its efficiency and its legitimacy. Evaluation is also used to account to policy-makers, who express doubts that the benefits of HIA justify its costs. Until recently evaluation of HIA focused on instrument design and procedures but now the focus needs to shift to analysis of the interaction of HIA and decision-making. Multiple case studies have been applied to identify the conditions in which HIA produces the desired benefits. These studies used analytical concepts derived from the literature on evaluation, knowledge utilization, science of sociology and knowledge management.This paper describes a case study in which the strategic motives of the decision-makers affected the impact of an HIA. This HIA comprised of a quantitative environmental model ‘City & Environment’ that was used to assess environmental health impacts of an urban reconstruction plan in a Dutch city. The evaluation of the HIA shows that the decision to follow the recommendations of the HIA was part of a damage control strategy. The more HIA goals deviate from the policy problem and the less HIA is embedded in institutional procedures, then the more HIA impact will be subject to strategic decision-making behaviour. Appropriate cognitive and social strategies are needed to avoid ‘negative learning’ in those the HIA seeks to influence.     

The evolution of the science of Bear Brook Watershed in Maine, USA

The Bear Brook Watershed in Maine (BBWM), USA is a paired watershed study with chemical manipulation of one watershed (West Bear = WB) while the other watershed (East Bear = EB) serves as a reference. Characterization of hydrology and chemical fluxes occurred in 1987–1989 and demonstrated the similarity of the ca. 10 ha adjacent forested watersheds. From 1989–2010, we have added 1,800 eq (NH₄)₂SO₄ ha^???1 y^???1 to WB. EB runoff has slowly acidified even as atmospheric deposition of SO $_{4}^{2-}$ has declined. EB acidification included decreasing pH, base cation concentrations, and alkalinity, and increasing inorganic Al concentration, as SO $_{4}^{2-}$ declined. Organic Al increased. WB has acidified more rapidly, including a 6-year period of increasing leaching of base cations, followed by a long-term decline of base cations, although still elevated over pretreatment values, as base saturation declined in the soils. Sulfate in WB has not increased to a new steady state because of increased anion adsorption accompanying soil acidification. Dissolved Al has increased dramatically in WB; increased export of particulate Al and P has accompanied the acidification in both watersheds, WB more than EB. Nitrogen retention in EB increased after 3 years of study, as did many watersheds in the northeastern USA. Nitrogen retention in WB still remains at over 80%, in spite of 20+ years of N addition. The 20-year chemical treatment with continuous measurements of critical variables in both watersheds has enabled the identification of decadal-scale processes, including ecosystem response to declining SO $_{4}^{-2}$ in ambient precipitation in EB and evolving mechanisms of treatment response in WB. The study has demonstrated soil mechanisms buffering pH, declines in soil base saturation, altered P biogeochemistry, unexpected mechanisms of storage of S, and continuous high retention of treatment N.