Effects of metal ions on Mg2+-ATPase activity in plasma membranes isolated from the rat uterus

In this study, we investigated the in vitro effects of metal ions on Mg²⁺-ATPase activity in isolated membranes from rat uterus. The effects of increasing concentrations of metal salts (CrCl₂, CuSO₄, HgCl₂ and ZnSO₄) show sigmoidal and almost complete inhibition relative to the control enzyme activity. According to the IC₅₀, the ATPase possesses greater sensibility to $ {\text{Zn}}^{{{\text{2}} + }} > {\text{Cu}}^{{{\text{2}} + }} \cong {\text{Cr}}^{{{\text{3}} + }} \cong {\text{Hg}}^{{{\text{2}} + }} ,$ {\text{Zn}}^{{{\text{2}} + }} > {\text{Cu}}^{{{\text{2}} + }} \cong {\text{Cr}}^{{{\text{3}} + }} \cong {\text{Hg}}^{{{\text{2}} + }} , while other metal salts exhibit the following inhibition: CdCl₂ 55%, CsCl 64.5% and SrCl₂ 58%. Here we demonstrated that the physico-chemical properties of these metals are of importance in defining possible mechanisms of binding and decrease of enzyme activity.     

Active biomonitoring with wet and dry moss: a case study in an urban area

Active biomonitoring of the air quality in Belgrade, Serbia, was performed using the moss Sphagnum girgensohnii. Moss bags were exposed in parallel with and without irrigation for 3 and 6 months, respectively, at three different sites. Twenty-nine elements were determined in the exposed moss samples by INAA. For all exposure periods, higher uptake in the irrigated moss bags was evident for Al, Cr, Fe, Zn and Sr. Elements such as Cl, K, Rb and Cs were depleted in the moss tissue during the time of exposure. For most of the elements the accumulation after 6 months exceeded that observed after 3 months.     

Bioaccumulation of lead and the influence of chelating agents in Catla catla fingerlings

Lead is a widespread element and one of the persistent and cumulative pollutants of the environment. The present study deals with the bioaccumulation of lead and the influence of chelating agents, meso 2,3-dimercaptosuccinic acid (DMSA), D-Penicillamine and CaNa₂EDTA in reducing the concentration of lead on the selected organs of Catla catla fingerlings for both acute and chronic exposures by using ICP-AES. It is inferred from the present findings that there was a correlation between environmental conditions and the heavy metal contents of the fish. The highest concentration of lead is found in kidney tissues and the lowest in muscle tissues. The accumulation pattern of lead in the selected organs of Catla catla is: kidney > liver > gill > brain > muscle. Also, it has been found that the treatment of chelating agents, DMSA, D-Penicillamine and CaNa₂EDTA reduces the concentration of lead significantly for both acute and chronic exposures. The results also show that DMSA is the most effective chelator of lead in reducing the body burden of C. catla fingerlings. The observed data further indicate that C. catla could be suitable for monitoring organisms to study the bioavailability of water-bound metals in freshwater habitats.     

Heavy metal distribution in soils near Palapye, Botswana: an evaluation of the environmental impact of coal mining and combustion on soils in a semi-arid region

Morupule Colliery near Palapye in eastern Botswana is the only coalmine in production in Botswana at present. Its coal is mainly used in the nearby coal-fired Morupule Power Station, which generates approximately 1,000 GWh of electricity per annum. After more than 30 years mining and more than 20 years of combustion, the sedimentation of outlet fly ash from the Morupule Power Station has increased concentrations of Cr, Ni, Zn and As by 13, 2.5, 16 and 5 ppm, respectively, in the fine portion (<53 μm) of surface soils for approximately 9 km downwind. Elements that have higher concentrations in coal have stronger small-particle association during coal combustion and are less mobile in surface soils, thus showing stronger contaminations in surface soils around the coal-fired plant. Although the degree of contamination of Cr, Ni, Zn and As from coal combustion in the Palapye area at present is low, it is necessary to monitor concentrations of these elements in surface soils routinely in the future. This study also reveals moderate Pb and Zn contaminations in the Palapye area. The former is due to the use of leaded petroleum in motor vehicle traffic and the latter is mainly due to the use of galvanized iron sheets in construction.     

Eine Weight-of-Evidence-Studie zur Bewertung der Sedimentbelastung und des Fischrückgangs in der Oberen Donau

Background and aim Despite intensive and continuous stocking and improvement of water quality since the 1970s, fish populations, especially those of the grayling (Thymallus thymallus), have declined over the last two decades in the upper Danube River (Germany). In order to assess 1) possible links between molecular/biochemical responses and ecologically relevant effects, and 2) if ecotoxicological effects might be related to the decline in fish catches in the upper Danube river, sediment samples and fish were collected at different locations and analyzed using a weight-of-evidence (WOE) approach with several lines of evidence. The objective of the presentation is to introduce the conceptual framework and to review results of the ongoing study. As previously addressed by Chapman and Hollert (2006) a variety of lines of evidence can be used in WOE studies. Briefly, 1) a comprehensive battery of acute and mechanism-specific bioassays was used to characterize the ecotoxicological hazard potential. 2) Histopathological investigations and the micronucleus assay with erythrocytes were applied, analyzing in situ parameters. 3) Diversity and abundance of benthic macroinvertebrates and fish as well as 4) persistent organic pollutants, endocrine disrupting substances, limnochemical parameters and the concentration of heavy metals were recorded. To identify organic contaminants a spotential causes of sediment toxicity assays, 5) effect directed analysis was applied.     

Stabilisotopenverdünnungsanalysen zur Quantifizierung organischer Spurenkomponenten in der Lebensmittelanalytik

Background and scope The principle and applications of stable isotope dilution assays (SIDAs) in food analysis is critically reviewed. This method is based on the application of internal standards labelled with stable isotopes. General topics The general section includes historical aspects of SIDAs, the prerequisites and limitations of the use of stable isotopically labelled internal standards along with possible calibrations procedures. The syntheses and availability of labelled food compounds for the use as internal standards is reviewed. Results The complete compensation for losses of analytes during clean-up as well as for ion suppression during LC-MS/MS and the so-called carrier effect are major advantages of SIDAs. However, deficient equilibration, spectral overlap and isotope effects can lead to false results. Discussion With regard to specificity and recovery, SIDAs generally are considered as the reference methods in clinical chemistry. In food chemistry, this method has been applied in flavour and pesticide analysis. However, it is becoming increasingly important also in the analysis of mycotoxins, further contaminants and vitamins. Conclusions The increasing access to isotopologic standards creates continuously new applications for SIDAs, particularly for bioactive compounds in foods.     

Reagenzienfreie Bestimmung von Quecksilberspuren in Wasserproben

A comprehensive ecological monitoring of hazardous substances is indispensable to preserve our health and environment. Therefore, fast and inexpensive techniques for routine analysis of pollutants are essential. However, in the measuring procedure itself often toxic reagents are used producing hazardous waste. Omitting environmentally hazardous substances in the analysis procedure is an important contribution to a more sustainable and green analytical chemistry. A reagent-free method for ultra-trace (pg to ng?L^-1) mercury determination in water samples was developed and validated. An active nanogold collector integrated in a fully automated flow injection system is the core of this new method. All mercury species dissolved in the water sample are adsorbed and preconcentrated on the nano-structured gold surface of the collector. After rinsing and drying of the collector, the enriched mercury is thermally desorbed and finally measured by atomic fluorescence spectrometry. This method was optimized and validated for the determination of mercury in natural waters. The influence of various water constituents was investigated and only high contents of dissolved organic carbon (DOC) showed interferences of mercury preconcentration due to the strong complexation of mercury by DOC. This restriction can be solved by UV-irradiation, i.?e. reagent-free digestion of DOC rich samples prior to the preconcentration procedure. Mercury concentration of several natural river and sea waters and water from the discharge of a waste water treatment plant were determined with this new analytical method. Accuracy and precision of the method were demonstrated by several recovery experiments in natural water samples (recoveries: 96–102?%) and by analysis of the certified reference material BCR-579 (Mercury in Coastal Sea Water; recovery: 101?±?1?%). With a detection limit of only 80?pg?Hg?L^–1 the proposed method is highly sensitive. Furthermore the method avoids potential contamination of the sample by reagent addition and is due to the reagent-free procedure environment-friendly. Hence this work is an important contribution to sustainable environmental analysis and at the same time improves accurate routine mercury trace analysis.     

Modelling semi-aquatic vertebrates’ distribution at the drainage basin scale: The case of the otter Lutra lutra in Italy

Modelling habitat suitability of semi-aquatic vertebrates for large scale conservation purposes is a particularly challenging task, due to the fine-scale linearity of riverine habitats, and to the ecological continuum represented by the riparian and the aquatic ecosystems, on one side, and by a river and its tributaries, on the other.     

Modelling the forest carbon budget of a Mediterranean region through the integration of ground and satellite data

This paper introduces an innovative modelling strategy aimed at simulating the main terms of net forest carbon budget (net primary production, NPP and net ecosystem exchange, NEE) in Tuscany (Central Italy). The strategy is based on the preliminary calibration and application of parametric and bio-geochemical models (C-Fix and BIOME-BGC, respectively), which simulate the behaviour of forest ecosystems close to equilibrium condition (climax). Next, the ratio of actual over-potential tree volume is computed as an indicator of ecosystem distance from climax and is combined with the model outputs to estimate the NPP and NEE of real forests. The per-pixel application of the new modelling strategy was made possible by the collection of several data layers (maps of forest type and volume, daily meteorological data and monthly normalized difference vegetation index (NDVI) images for the years 1999–2003) which served to characterize the eco-climatic and forest features of the region. The obtained estimates of forest NPP and NEE were evaluated against ground measurements of accumulated woody biomass and net carbon exchange. The results of these experiments testify the good potential of the proposed strategy and indicate some problem areas which should be the subject of future research.     

Linking species- and ecosystem-level impacts of climate change in lakes with a complex and a minimal model

To study the interaction between species- and ecosystem-level impacts of climate change, we focus on the question of how climate-induced shifts in key species affect the positive feedback loops that lock shallow lakes either in a transparent, macrophyte-dominated state or, alternatively, in a turbid, phytoplankton-dominated state. We hypothesize that climate warming will weaken the resilience of the macrophyte-dominated clear state. For the turbid state, we hypothesize that climate warming and climate-induced eutrophication will increase the dominance of cyanobacteria. Climate change will also affect shallow lakes through a changing hydrology and through climate change-induced eutrophication. We study these phenomena using two models, the full ecosystem model PCLake and a minimal dynamic model of lake phosphorus dynamics. Quantitative predictions with the complex model show that changes in nutrient loading, hydraulic loading and climate warming can all lead to shifts in ecosystem state. The minimal model helped in interpreting the non-linear behaviour of the complex model. The main output parameters of interest for water quality managers are the critical nutrient loading at which the system will switch from clear to turbid and the much lower critical nutrient loading – due to hysteresis – at which the system switches back. Another important output parameter is the chlorophyll-a level in the turbid state. For each of these three output parameters we performed a sensitivity analysis to further understand the dynamics of the complex model PCLake. This analysis showed that our model results are most sensitive to changes in temperature-dependence of cyanobacteria, planktivorous fish and zooplankton. We argue that by combining models at various levels of complexity and looking at multiple aspects of climate changes simultaneously we can develop an integrated view of the potential impact of climate change on freshwater ecosystems.