11 research outputs found
Hydrogeochemical Features of Some Mineral Waters at the Contact between Harghita Mts. (Eastern Carpathians) and the Transylvanian Basin
AbstractThe study area, located at the contact zone between the Harghita Mountains and the Transylvanian Basin is well known for the abundance and diversity of mineral water springs. These mineral waters are used by the local people for drinking and also as Spas. This paper focuses on the mineral waters of some traditional Spas from this area, Odorheiu Secuiesc (Seiche Spa, Kápolnás Spa or Solymossy Spa), Upper Vârghiş Valley (Selters Spa and Nádasszék Spa) and Chirui Spa. The aim of the present work is to characterize the mineral waters based on the quantification of chemical content and also to establish correlations between the geological structure and the water's chemical composition. The geological setting and tectonics have a large influence on the chemical composition of mineral waters. Two main water types can be described, mineral waters of Na+ – Cl- type, present at Odorheiu Secuiesc, Kápolnás Spa and of HCO3- type with no dominant cation at Chirui Spa. The mineral waters located on a fault at Odorhei Seiche Spa have high CO2 values. Possible mixing zones might be identified between the two types which are present in the Upper Vârghiş Valley where mineral waters of Na+ – HCO3-– Cl- type are present except one source, which is of Na+ – Cl- type. The mixing is reflected not only by the chemical composition, but also by the quantity of dissolved CO2. The present paper deals with all the existing mineral water springs in the area providing information in a high resolution about the local hydromineral system
Metal-induced abnormalities in diatom girdle bands
P. 1-14There have been a number of studies that described a serial of type of teratology occurring in different diatom taxa and that highlight the relation between metal concentration and diatom deformities, but this subject still remain not deeply understood. The present study refers to the effect of metal pollution on the diatom Achnanthidium minutissimum s.l. by describing a new form of teratology. The samples were collected in a mine area, Rosia Montana, from Romania. We observed that, exposed to environmental stress, the frustule of diatom cells appeared altered in several ways, with abnormal forms occurring in different diatom species that presented deformed valve outlines, modifications of the raphe canal system, irregular striation or mixed teratologies. In a particular sampling location where A. minutissimum s.l. was identified as the dominant species, 20.53% of the individuals presented an unreported type of deformity. This kind of teratology affects the cingulum, the valvocopula more exactly, by becoming markedly undulat
Naturally and Environmentally Driven Variations in Diatom Morphology: Implications for Diatom-Based Assessment of Water Quality
Diatom identification must consider the large variability in both morphological and morphometric features, characteristic of this group of microorganisms. This chapter describes variations in shape/size observed in diatom populations either as a consequence of their particular asexual reproductive cycle or induced by environmental conditions. Concerning this latter, teratological diatoms are commonly associated with a variety of environmental stressors, particularly the presence of micropollutants in the aquatic ecosystem, such as heavy metals. We evidence an overestimation of water quality conditions caused by overriding deformed individuals in diatom-based biomonitoring studies. It can be shown that normal and aberrant forms of the same taxon differ in autecological preferences. Finally, we advise on a critical issue in the description of diatom specimens, that is, the sample size on which morphometric ranges should be provided. The section concludes with some recommendations in this regard
Neoteric Material Based on Renewable Resources for Metal-Contaminated Waters
A continuous increase of environmental pollution has been recorded worldwide, during recent decades, as a result of industrialization and urbanization. In particular, metal release in the environmental media may threaten human health, due to their persistence and accumulation in the food chain. We report here the functionalization of chitosan with poly(benzofurane-co-arylacetic) acid, which is a new material with the ability of complex metals from contaminated water. The synthesized polymer was structurally investigated by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), X-ray photon electron microscopy (XPS), and Fourier-transform infrared spectroscopy (FTIR), while heavy metals were determined by atomic absorption spectrometry. Different isotherms and kinetic models were used to describe the absorption equilibrium and the behavior of the material, based on the initial pollutant concentration and contact time. The results are pointing out that such natural materials can be easily synthesized, at low costs, thus offering attractive solutions for wastewater treatment
Mapping social vulnerability to floods. A comprehensive framework using a vulnerability index approach and PCA analysis
In recent years, the analysis of social vulnerability to floods became an integrated part of the flood risk management process, the strategies and policies developed focusing on risk reduction methods that increase the resilience of vulnerable communities. Therefore, reliable and robust social vulnerability approaches are needed, which is also highlighted by the increasing socio-economic growth and climate change related effects that can lead to unpredictable consequences. The use of vulnerability indices is the most widespread methodology that allows the identification of the most vulnerable communities and the understanding of the factors that increase vulnerability to floods. However, due to the lack of a standard procedure, the existing studies are often characterized by uncertainties related to subjective selection of indicators, lack of inclusion of all vulnerability dimensions, equal or subjective weighting methods, and reduced number of variables due to data unavailability. The present paper is addressing these gaps by developing a comprehensive methodology approach which: includes a large set of indicators that are selected considering the local socio-economic context, includes the hazard dimension in the analysis considering flood related variables, and applies objective weighting methods based on the Principal Component Analysis (PCA) method. Furthermore, flood vulnerability maps are developed using Geographic Information System (GIS) tools, to provide a rapid and easy way to identify highly vulnerable areas. The results showed that the integration of statistical methods and GIS tools in the social vulnerability index construction provides a better understanding of the factors that increase the social vulnerability and offers an overview of the mitigation and adaptation measures that must be implemented by authorities in order to improve the flood risk management
Development of a New Eco-Friendly Copolymer Based on Chitosan for Enhanced Removal of Pb and Cd from Water
Worldwide, concerns about heavy metal contamination from manmade and natural sources have increased in recent decades. Metals released into the environment threaten human health, mostly due to their integration into the food chain and persistence. Nature offers a large range of materials with different functionalities, providing also a source of inspiration for scientists working in the field of material synthesis. In the current study, a new type of copolymer is introduced, which was synthesized for the first time by combining chitosan and poly(benzofurane-co-arylacetic acid), for use in the adsorption of toxic heavy metals. Such naturally derived materials can be easily and inexpensively synthesized and separated by simple filtration, thus becoming an attractive alternative solution for wastewater treatment. The new copolymer was investigated by solid-state nuclear magnetic resonance, thermogravimetric analysis, scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray photon electron microscopy. Flame atomic absorption spectrometry was utilized to measure heavy metal concentrations in the investigated samples. Equilibrium isotherms, kinetic 3D models, and artificial neural networks were applied to the experimental data to characterize the adsorption process. Additional adsorption experiments were performed using metal-contaminated water samples collected in two seasons (summer and winter) from two former mining areas in Romania (Roșia Montană and Novăț-Borșa). The results demonstrated high (51–97%) adsorption efficiency for Pb and excellent (95–100%) for Cd, after testing on stock solutions and contaminated water samples. The recyclability study of the copolymer indicated that the removal efficiency decreased to 89% for Pb and 58% for Cd after seven adsorption–desorption cycles
Occurrence, distribution and ecological risk of trace metals and organic pollutants in surface sediments from a Southeastern European river (SomeÅŸu Mic River, Romania)
International audienceIn the present study, we investigated, for the first time, the distribution, sources and ecological risk of trace metals and organic pollutants, including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs), in surface sediments from a Southeastern European river (Someşu Mic River, Romania). Concentrations of Cd, Cr, Cu, Pb, Ni and Zn ranged from 0.04 to 0.4, 9.4 to 43.15, 7.2 to 65.6, 12.3 to 131.4, 14.7 to 47.7 and 42.1 to 236.8 mg kg-1 dw, respectively. Concentrations of total PAHs, PCBs and OCPs ranged from 24.8 to 575.6, 2.7 to 252.7 and 2.1 to 44.3 ng g-1 dw, respectively. 2 Some sediment parameters, i.e., pH, total organic carbon (TOC) and total organic matter (OM) contents, played a significant role in the spatial distribution of contaminants. A combined analysis based on diagnostic ratios and multivariate analyses revealed PAHs originating mainly from pyrolytic sources. PCB compositions showed distinct contamination signatures for tri-to tetra-chlorinated PCBs, characteristic of contamination by Aroclor-1016 and-1254 technical mixtures. The dominant OCP congeners were α-HCH and p,p′-DDD, reflecting a past use of technical HCHs and DDTs in agricultural practices. Metal source and pollution status was assessed using geoaccumulation index and enrichment factor, which indicate a widespread pollution by Pb, Cd, Zn, Ni and Cu. The use of Sediments Quality Guidelines (SQGs), mean effect range-median quotient (m-ERM-Q) and toxic equivalent factor (TEF) indicated that the highest ecological risks occurred for PCBs and DDTs. This work presents not only initial baseline information on the extent of organic and inorganic contaminations in a river of ecological and economical interest, but also provides a diagnostic ratio/statistical combined approach that can be used to evaluate sediment quality in similar environments
Laboratory development of Dermacentor marginatus ticks (Acari: Ixodidae) at two temperatures
The influence of two temperatures on the development of Dermacentor marginatus evolutive cycle was studied. Tests performed under controlled laboratory conditions at 21 A degrees C, 80 % RH and 27 A degrees C, RH 80 %, on ten fully engorged female ticks collected from naturally infested goats, in Cluj County, Romania. Hatched larvae were fed on white mice and the nymphs and adults on guinea pigs. The following parameters were evaluated: egg incubation; pre-feeding, feeding and pre-moulting for larvae and nymphs; pre-feeding, feeding, pre-oviposition and oviposition for females. Significant differences (p < 0.001) were observed in: egg incubation period (29.4 +/- A 1.07 at 21 A degrees C; 5.9 +/- A 0.73 at 27 A degrees C) and pre-moulting duration of larvae (18.9 +/- A 1.02 at 21 A degrees C; 6.1 +/- A 0.58 at 27 A degrees C) and nymphs (21.3 +/- A 0.87 at 21 A degrees C; 19.9 +/- A 0.71 at 27 A degrees C). The average duration of the developmental cycle was 133.9 days (range 122-154 days) at 21 A degrees C, and 94.2 days (range 83-111 days) at 27 A degrees C