Evaluation in situ of genotoxicity and stress in South American common toad <Emphasis Type="Italic">Rhinella arenarum</Emphasis> in environments related to fluorite mine

Little attention has been paid to the impact of wastewater generated by mining activities on fluoride. In this study, we evaluated the hematology responses of common South American toad Rhinella arenarum inhabiting natural and artificial environments associated with a fluorite mine from central Argentina. We analyzed three sampling stations associated with the fluorite mine: (I) Los Cerros Negros stream (CN), which runs on granitic rock with a high fluorite content; (II) Los Vallecitos stream (LV), which runs on metamorphic rock with low fluorite content; and (III) artificial decantation ponds (DP) containing sediments produced by fluorite flotation process. We calculated frequencies of micronuclei, erythrocyte nuclear abnormalities, mitosis, and immature erythrocytes. In addition, we performed a differential leukocyte count and determined neutrophils/lymphocyte ratio as a stress response estimator. We found high micronucleus (MN) and erythrocyte nuclear abnormality (ENA) frequencies in DP and CN but low frequencies in LV. The neutrophil/lymphocyte ratio was different among sites, with a significant increase in individuals from DP. Values registered in DP could be caused by exposure to mixture of compounds registered in dams that hold wastewater, while high values registered in CN stream might be due to natural concentrations of fluoride. Our results suggest that blood is an effective and non-destructive sensitive indicator for monitoring genotoxic agents in freshwater ecosystems.     

A new approach for the modelling of chestnut wood photo-degradation monitored by different spectroscopic techniques

The aim of this work is to study the colour and chemical modifications of the surfaces in chestnut wood samples as a consequence of irradiating in a controlled environment. The changes were investigated by a new analytical approach by combining traditional techniques such as reflectance spectrophotometry in the visible range and Fourier transform infrared spectroscopy with new hyperspectral imaging, in order to obtain forecast models to describe the phenomenon. The statistical elaboration of the experimental data allowed to validate the measurements and to obtain models enabling to relate the investigated parameters; the elaboration of the hyperspectral images by chemometric methods allowed for studying the changes in the reflectance spectra. A result of great importance is the possibility to correlate the oxidation of wood chemical components with the colour change in a totally non-invasive modality. This result is particularly relevant in the field of cultural heritage and in general in the control processes of wooden materials.     

Sustainable forest management in a mountain region in the Central Western Carpathians,northeastern Slovakia: the role of climate change

European forestry is facing many challenges, including the need to adapt to climate change and an unprecedented increase in forest damage. We investigated these challenges in a Norway spruce-dominated mountain region in Central Europe. We used the model Sibyla to explore forest biomass production to the year 2100 under climate change and under two alternative management systems: the currently applied management (CM), which strives to actively improve the forest’s adaptive capacity, and no management (NM) as a reference. Because biodiversity is thought to have mostly positive effects on the adaptive capacity of forests and on the quality of ecosystem services, we explored how climate change and management affect indicators of biodiversity. We found a differential response across the elevation-climatic gradient, including a drought-induced decrease in biomass production over large areas. With CM, the support of non-spruce species and the projected improvement of their growth increased tree species diversity. The promotion of species with higher survival rates led to a decrease in forest damage relative to both the present conditions and NM. NM preserved the high density of over-matured spruce trees, which caused forest damage to increase. An abundance of dead wood and large standing trees, which can increase biodiversity, increased with NM. Our results suggest that commercial spruce forests, which are not actively adapted to climate change, tend to preserve their monospecific composition at a cost of increased forest damage. The persisting high rates of damage along with the adverse effects of climate change make the prospects of such forests uncertain.     

Long-term change in drivers of forest cover expansion: an analysis for Switzerland (1850-2000)

Regional Environmental Change - The spatial distribution of forests in Europe represents the legacy of centuries of human land use decisions. Due to the limited availability of historical data,...     

Health risk assessment of potentially harmful elements and dietary minerals from vegetables irrigated with untreated wastewater,Pakistan

In the developing world, vegetables are commonly grown in suburban areas irrigated with untreated wastewater containing potentially harmful elements (PHEs). In Pakistan, there is no published work on the bioaccessibility aspect of PHEs and dietary minerals (DMs) in sewage-irrigated soil or the vegetables grown on such soils in Pakistan. Several industrial districts of Pakistan were selected for assessment of the risk associated with the ingestion of vegetables grown over sewage-irrigated soils. Both the total and bioaccessible fraction of PHEs (Cd, Co, Cr, Ni, and Pb) and DMs (Fe, Cu, Mn, Zn, Ca, Mg, and I) in soils and vegetable samples were measured. The concentrations of these PHEs and DMs in sewage-irrigated and control soils were below published upper threshold limits. However, compared to control soils, sewage irrigation over the years decreased soil pH (7.7 vs 8.1) and enhanced dissolved organic carbon (1.8 vs 0.8 %), which could enhance the phyto-availability of PHEs and DMs to crops. Of the PHEs and DMs, the highest transfer factor (soil to plant) was noted for Cd and Ca, respectively. Concentrations of PHEs in most of the sewage-irrigated vegetables were below the published upper threshold limits, except for Cd in the fruiting portion of eggplant and bell pepper (0.06–0.08 mg/kg Cd, dry weight) at three locations in Gujarat and Kasur districts. The bioaccessible fraction of PHEs can reduce the context of dietary intake measurements compared to total concentrations, but differences between both measurements were not significant for Cd. Since the soils of the sampled districts are not overly contaminated compared to control sites, vegetables grown over sewage-irrigated soils would provide an opportunity to harvest mineral-rich vegetables potentially providing consumers 62, 60, 12, 104, and 63 % higher dietary intake of Cu, Mn, Zn, Ca, and Mg, respectively. Based on Fe and vanadium correlations in vegetables, it is inferred that a significant proportion of total dietary Fe intake could be contributed by soil particles adhered to the consumable portion of vegetables. Faecal sterol ratios were used to identify and distinguish the source of faecal contamination in soils from Gujranwala, Gujarat, and Lahore districts, confirming the presence of human-derived sewage biomarkers at different stages of environmental alteration. A strong correlation of some metals with soil organic matter concentration was observed, but none with sewage biomarkers.     

Elemental concentrations and in vitro bioaccessibility in Canadian background soils

Elemental concentrations and bioaccessibility were determined in background soils collected in Canada as part of the North American Geochemical Landscapes Project. The concentrations of As, Cr, Cu, Co, Ni and Zn were higher in the C-horizon (parent material) compared to 0–5 cm (surface soil), and this observation along with the regional distribution suggested that most of the variability in concentrations of these elements were governed by the bedrock characteristics. Unlike the above-stated elements, Pb and Cd concentrations were higher in the surface layer reflecting the potential effects of anthropogenic deposition. Elemental bioaccessibility was variable decreasing in the order Cd > Pb > Cu > Zn > Ni > Co > As > Cr for the surface soils. With the exception of As, bioaccessibility was generally higher in the C-horizon soils compared to the 0–5 cm soils. The differences in metal bioaccessibility between the 0–5 cm and the C-horizon and among the provinces may reflect geological processes and speciation. The mean, median or 95th percentile bioaccessibility for As, Cr, Cu, Co, Ni and Pb were all below 100 %, suggesting that the use of site-specific bioaccessibility results for these elements will yield more accurate estimation of the risk associated with oral bioavailability for sites where soil ingestion is the major contributor of human health risk.     

Isotopic composition (C & N) of the suspended particles and N uptake by phytoplankton in a shallow tropical coastal lagoon

The spatial distribution of the C/N ratios and variations in δ¹³C and δ¹⁵N of suspended particulate matter were used to characterise their source in Asia’s largest brackish water lagoon, Chilika, India. In addition, the significance of re-mineralised nutrients in the primary productivity of the shallow lagoon was also determined through quantification of the subsurface nitrogen uptake conditions at two relatively stable locations in the lagoon. The results indicated that the influence of terrestrial organic matter was the maximum in the northern sector and was relatively limited at the central and southern part of the lagoon. In situ ¹⁵N uptake experiments (daytime) under biogeochemically stable conditions revealed that the N uptake by phytoplankton ranged between 0.24 and 1.01?mM?m^?3?h^?1 during pre-monsoon and post-monsoon seasons. New production and regenerated production in the shallow lagoon was also estimated by calculating f-ratios (ratio of nitrate assimilation by phytoplankton to total nitrogenous nutrient assimilation, have been estimated), which varied from 0.52 in the post-monsoon to 0.38 in the pre-monsoon. Lowering of the f-ratio from post- to pre-monsoon indicated a dominance of mineralisation over the new production.     

A study on the arsenic concentration in groundwater of a coastal aquifer in south-east India: an integrated approach

The occurrence of arsenic in drinking water and its detrimental effects have drawn much attention in recent years. Several studies have been conducted in the deltaic plains of River Ganga, NE part of the India, and in other countries, but no systematic study was conducted in South India on occurrence of arsenic in groundwater. The main aim of this study is to determine the level of arsenic in groundwater and to understand the relation with other geochemical parameters of groundwater in the south-eastern coastal aquifer at Kalpakkam region, India. This region is represented by three different lithologies, viz. charnockites, flood plain alluvium and marine alluvium. Twenty-nine representative samples of groundwater were collected and analysed for major ions, metals and isotopes such as ²H and ¹⁸O. In addition, geophysical method was also attempted to understand the subsurface condition. The spatial variation in arsenic (As) indicates that higher concentration was observed around the landfill sites and irrigated regions, which was supported by geochemical, statistical and isotopic inferences. The variation in the As with depth, lithology and sources has been clearly brought out. Though the values of As does not exceed the drinking water permissible limit (10 mg/l), it has reached a near permissible level of 8.7 ppb. Hence, it is essential to understand the geochemical behaviour of As for a proper future management of the water resource in the study area.     

A Comprehensive Python Toolkit for Accessing High‐Throughput Computing to Support Large Hydrologic Modeling Tasks

The National Flood Interoperability Experiment (NFIE) was an undertaking that initiated a transformation in national hydrologic forecasting by providing streamflow forecasts at high spatial resolution over the whole country. This type of large‐scale, high‐resolution hydrologic modeling requires flexible and scalable tools to handle the resulting computational loads. While high‐throughput computing (HTC) and cloud computing provide an ideal resource for large‐scale modeling because they are cost‐effective and highly scalable, nevertheless, using these tools requires specialized training that is not always common for hydrologists and engineers. In an effort to facilitate the use of HTC resources the National Science Foundation (NSF) funded project, CI‐WATER, has developed a set of Python tools that can automate the tasks of provisioning and configuring an HTC environment in the cloud, and creating and submitting jobs to that environment. These tools are packaged into two Python libraries: CondorPy and TethysCluster. Together these libraries provide a comprehensive toolkit for accessing HTC to support hydrologic modeling. Two use cases are described to demonstrate the use of the toolkit, including a web app that was used to support the NFIE national‐scale modeling.