Suchergebnisse

In this paper, a chromatographic method for the determination of volatile organic compounds (VOCs) as a tool for Gram-positive and Gram-negative bacterial strains identification was described. Direct Headspace gas chromatography coupled with mass spectrometry (Headspace-GC-MS) has been used for the qualitative determination of VOCs emitted by certain bacterial strains (Salmonella Typhimurium, Escherichia coli, Serratia rubidae, Staphyloccocus aureus, Enterococcus casseliflavus, and Enterococcus faecalis). In the first stage of the study, pathogenic bacteria were cultured in broth-specific liquid culture medium directly (lauryl sulfate broth) into headspace vials. Subsequently, the VOC emissions were analyzed by airborne screening in the headspace vials. Thus, the objective was to analyze all the resulting volatile organic compounds in order to select only those compounds, which can be exclusively associated with specific pathogenic bacteria. Qualitative analysis by Headspace-GC-MS has proven to be a non-invasive, accurate, and fast method for identifying certain bacterial strains, based on VOCs emission. A considerable number of volatile organic compounds have been determined in the headspace air, a significant difference being observed between the VOCs emitted by bacterial cultures compared to the culture medium but also between the types of bacterial cultures themselves. The study presents preliminary results, which prove that the identification of the studied pathogenic bacteria is possible, based on the determination of certain types of VOCs in the headspace air of these cultures. This method can be used successfully for the rapid identification of bacterial culture types compared to classical methods.

The study focused on odours generated by hydrogen sulphide (H2S) immissions from a municipal wastewater treatment plant in a city of 2 million people. Odour awareness was vital to monitor environmental pollution and human's safety. H2S was released from decomposition of organic matter, sulphites (SO32-) and sulphates (SO42-) by anaerobic microorganisms used in the biological stage of wastewater treatment. H2S was responsible for odours coming from the treatment plant. Long exposure (8 hours) to 2-5 ppm causes headaches and watery eyes, and 50 ppm irritates the airways. Maximum permissible concentrations for H2S are 0.006 ppm (24 hours) and 0.011 ppm (30 minutes). In Romania there are no limits on the concentration of odours. The sludge pumping station from the wastewater treatment plant registered the highest odour concentration at 36.000 OUE/m3, with significant levels of H2S primarily found there. Nevertheless, the activated sludge aeration system effectively eliminated around 99% of the H2S through degradation and absorption processes. The correlation between H2S and odour has been proved by a direct proportional relationship with a ratio of 25.000. Experimental determinations and mathematical modelling, using the Aermod View program, contributed to a deeper understanding of the impact of odours on the environment and on sensitive receptors, showed maximum odour concentrations of 38.8 ouE/m3 at the site of the municipal wastewater treatment plant and 5 ÷7 ouE/m3 at receptors, but without affecting residential areas.

In this paper, an assessment study was performed regarding air pollution with particulate matters including submicron particles. The evaluation of the contamination level was performed at a textile production unit in Pascani, Romania, which produces polyester knitwear. In the study, automatic determinations of total suspended particulate matters (TSP), PM 10, PM 2.5, and PM 1 (particle with nominal diameter <10 µm, <2.5 µm, and <1 µm), and submicron particulate matters (0.25, 0.35, 0.50 and 0.70) were performed both outdoor, in the ambient air, and indoor (workplace) in the area of the knitting machines. The correlation between the mass concentrations of submicronic particles (µg/m 3) and the numerical concentrations (number of particles/m3) was studied, too, to establish the most appropriate expression of the air pollution level with particulate matter. The results of the performed tests showed a level of ambient air pollution with particulate matters that exceed the limit values in the case of PM 2.5 and PM 10, the total suspended particulates still falling within the limits established by law. Likewise, in the case of workplace air, the level of inhalable particulate matter (particles with nominal diameter <100 µm), the concentration is below the limit values. Regarding the way of expressing the concentration of air particles, in µg/m3 or in no. particles/m3 the tests indicated better representativeness of the pollution level if the concentration in µg m3 is expressed for the dimensional fractions with diameter ≥ 1 µm and in no. particles/m3 for particles with a diameter of ≤1 µm.

A serious problem that arose with the evolution of modern industry is generation of electrical and electronic equipment waste. In the last decades, the generation of electronic waste has increased a lot and it is estimated that in 2030, almost 74 tons of electronic waste will be generated, which will represent a significant threat to the environment. The purpose of this article is to track the potential impacts on the environment, to highlight the importance of waste management strategies and to provide the latest information in the field. A presentation of the countermeasures that must be taken at the national and international level to address the sensitive problem of waste management is also realized.

In the current context of the transition to a circular economy, efforts are primarily focused on recycling, the reintegration of some wastes into the economy, as a secondary raw material. The recovery of wastes specific to the mining industry and the metallurgical industry, which through the quantities deposited and through the chemical composition put a great pressure on the environment, represents a major concern of the society. Starting from this aspect, the paper presents the results of the research carried out in order to obtain new building materials (mortars) by adding two mineral wastes - red sludge from the manufacture of alumina and mine tailings - in the basic raw material, cement. The performances of the new materials containing the two wastes prove the viability of the technical solutions so that they can be used in the field of construction, both as masonry mortars and as plastering mortars.

Organic fractions assessment in influent wastewater is essential for designing the biological wastewater treatment plant. The characteristics of the influent organic load (readily biodegradable, biodegradable or inert) and form of distribution (soluble/suspended) may induce the design and operational parameters of primary settlers and biological treatment step. The current work presents the comparative assessment of organic fractions in three wastewater samples evaluated experimentally through three different fractionation methodologies, respectively modified ATV-A131 guidelines, IWA methodology and the Łomotowski-Szpindor methodology. The wastewater samples were collected from the influent of two municipal wastewater treatment plants. In all wastewater samples tested the biodegradable fractions, both soluble and suspended had the highest share in the total organic load. This is consistent with the biodegradable character of municipal influents and the suitability for organic and advanced nutrient removal through biological processes. The amount of non-biodegradable fractions SI and XI, varied from 18 to 54% of total organic load, on momentary grab samples of studied influents.

Today, the growth in textile consumption is influenced by the increasing population. This leads to the generation of a large volume of textile waste, which has a negative impact on the environment. Textile waste is mainly disposed of by landfill or incineration. To reduce the amount of textile waste disposed of, it can be recovered and transformed into valuable compounds, such as ethanol (bioethanol). This article describes how pre- and post-consumer textile waste is used as a feedstock for ethanol.

The aim of the study was to develop a new method for mercury determination from plants grown on mercury-polluted soils as well as to evaluate the mobility and bioavailability of mercury in the soil and its transfer to different plant organs (root, stem, leaves) from three different plants, such as mustard (Sinapis alba), thyme (Thymus serpyllum) and wild thyme. A cold vapor atomic absorption spectrometry (CV-AAS) method for the detection of mercury in plants was developed. The developed method was validated in the laboratory and was verified using two different certified reference materials (CRMs) type matrices, namely: NIST 1515 Apple Leaves and BCR-482 Lichen.

The SARS-CoV-2 pandemic situation put extreme pressure on the worldwide medical system from medical personnel to medical equipment. The protective face mask became the front line of anti-SARS-CoV-2 prevention methods, used by most of the world population, more than 7 billion people. The massive demand for face masks activated the world market, where countries from different continents increased their mask production and commercialization worldwide. Unfortunately, the focus on face mask production mostly relied on their ability to filter small-size molecules and less on their microbiological sterile status. Since bacterial structural communities could differ between various large populational groups or continents, in this study, we analyzed the microbial quality of face masks received from various countries/continents. There were analyzed the microbiological load of four types of masks, three from China and one from Romania. The bacterial density from masks was analyzed by membrane filtration and swabbing bacterial collection techniques. The results showed the Romanian mask had a smaller bacterial load than the Chinese masks. In addition, the bacterial identification showed a wide range of bacterial strains, quite different between face mask types.

The hydrosphere represents about 71% of the total surface of the planet of which only 2.8% is represented by freshwater ecosystems. The ecosystem maintains a state of balance between the component populations, throughout its self-control function, maintaining the numerical variations of these populations within certain limits of sustainability. The exceeding of these limits could causes the balance disturbance by changing the structure and functioning of the ecosystem. The complex human activities influence the structure and functioning of ecosystems, transforming the environment and adapting it to its purposes. Microorganisms are present in all types of ecosystems, being endogenous, exogenous or transient due to contamination with various sources of pollution. Water is an essential natural factor of ecological balance increasingly exposed to microbial pollution. Indicators of fecal pollution are used to assess the degree of water contamination and to locate its origin. The continuous and uncontrolled usage of antibacterial agents that contributed to bacterial resistance determined/ caused pollution of aquatic ecosystems with antibiotic resistant microorganisms. The emergence of antibiotic resistant bacteria is predictable in any environment given that the use of antibacterial substances is constantly growing worldwide. Thus, antibiotic resistance induced in the aquatic environment can have an effect both on bacterial populations in the ecosystem and on human health. Aquatic environments are recognized as one of the reservoirs for the transmission and dissemination of antibiotic resistance. The main goal of this paper is to highlight the differences of bacterial communities from anthropogenic and natural aquatic ecosystems and to assess the potential impact they have on environment and human health. The study area focused on two lakes in Bucharest, Lake Morii (anthropic) and Lake Snagov (natural). Microbiological and molecular biology methods were applied for a bacterial communities' characterization. The fecal indicators were quantified by Most Probable Number method. The identification and characterization of bacterial populations in both aquatic ecosystems (Morii Lake and Snagov Lake) were performed by Omnilog (Biolog, USA) and by iSeq100 (Illumina, USA) gene sequencing techniques from bacterial aquatic ecosystem. Antibiotic susceptibility was tested following CLSI recommendation.

Microplastics pollution represents a stringent global issue. Their accumulation in the aquatic environment remains complicated due to the abundance, distribution, and resulting environmental effects they induce. Recently, assessing the toxicity level of aquatic organisms has gained scientific interest. Due to the diverse types and sizes of polymers present in the environment, the detection and evaluation of their effects are still a challenging issue. Polyethylene (PE) and polystyrene (PS) are the most commonly used polymers and are therefore predominantly detected in both marine and freshwater aquatic environments. This paper aims to evaluate the effects of Red Nile-stained PE and PS, tested in different particle sizes (PE 40-48, 125, >125 µm, and PS 20, 200, 430 µm) on Daphnia magna, and highlight them through microscopic analysis. Acute toxicity tests conducted over a 48-hours exposure did not reveal significant toxicity effects in terms of mortalities compared to the controls. Red Nile staining allowed the visualization of the shapes and sizes of the tested microplastics and their entry pathways into the Daphnia bodies. PS of 20 µm size was detected in the digestive tract of Daphnia, indicating as primary pathway of entry into the body of aquatic organisms. No acute toxic effects were recorded as a result of direct exposure to PE and PS particles. However, sub-lethal effects such as feeding and growth disturbances, which could affect organisms in the long term, are suspected.

The aim of this study was to evaluate the quality of environmental factors of soil and water in a protected area in Romania, namely the Preajba-Facai lake system in Dolj County. Highlighting the evolutionary aspects of the analyzed quality parameters (20 physical-chemical indicators) on a spatial-temporal scale in order to establish geochemical thresholds is the final result of a larger project. The presented results were obtained through seasonal monitoring over a period of 3 years, which involves water and soil sampling and subsequent laboratory analysis. The results obtained were interpreted in relation to the legislation in force and through a more suggestive evaluation by calculating the pollution indices: the global pollution index (IPC) for water and the Nemerov synthetic soil contamination index. Following the field visits, additional information was brought, which contributed to a good knowledge of this region. Although protected, the area is influenced by anthropogenic factors, which negatively impact the environment. In some cases, non-conformities were identified and validated through the analysis performed.

The aim of the study was to develop alternative adsorbent materials based on pyritic ash, with high iron content, in order to retain phosphates from wastewater. Experimental studies of phosphate removal efficiency have shown that the phosphates removal from water using pyritic ash adsorbent materials is strongly influenced by some parameters such as: contact time, stirring speed, amount of adsorbent material or iron content. An increase of phosphate removal efficiency up to 53% could be observed for iron-rich adsorbent materials (PA1) by increasing the contact time to 6 hours and the stirring speed to 100 rpm. An increase of phosphate removal efficiency was also observed by increasing the amount of adsorbent material from 0.1 g to 0.5 g for all three adsorbent materials studied (PA1, PA2, PA3). The best efficiency was shown for PA1 (53.13%), while PA3 showed the lowest efficiency (19.74%).

The current context of the increasing manifestation of climate change in the form of extreme weather phenomena prioritizes efforts to find solutions as quickly as possible to ensure adaptation to these new conditions and to achieve climate resilience. The phenomena are problematic, they usually cause much material damage, and therefore knowing the particularities of each urban or peri-urban environment where they occur can ensure the finding of viable and sustainable solutions in the long term. The current knowledge of the phenomena related to pollution and the variation of some climatic parameters, such as temperature and humidity, can bring valuable information for understanding the phenomena that appear against the background of the manifestation of climatic changes in urban environments and those adjacent to them. The analysis presented in this article refers to three cities in Romania, analyzed as case studies, for understanding climatic vulnerabilities in parallel with a quantification of the quality of environmental factors, in an integrated air, water, and soil approach. In these areas, the manifestation of natural factors, together with the anthropic footprint, particularly more evident in the urban environment, offers the possibility of an objective, quantifiable evaluation of the studied areas. The proposed comparisons will allow highlighting the vulnerabilities together with the zonal variability that is the basis of the influencing factors, as well as how the quality of the monitored parameters will evolve in space and time.

In this study, the area of a biofilter representing an active area source was sampled by taking 12 odour samples from the gaseous effluent and measuring the physical parameters of the source, so that we can obtain the odour emission rate (OER) specific to the source. The odour sampling process is a crucial step in the assessment and monitoring of odour pollution. Direct measurement of odour concentration in the ambient air is often not sufficient to determine whether an activity is responsible for producing olfactory discomfort to the receptors. To observe the contribution of the source to olfactory pollution and air quality by estimating the odour concentration in the ambient air, the odour emission rate (OER) was taken into account, which is expressed in odour units per second (ouE/s) and is obtained as the product of the odour concentration and the airflow rate associated with the source. The odour emission rate was entered into the dispersion program AERMOD for mathematical modeling. In order to estimate the odour concentration in the surrounding air in the adjacent areas to the sampled biofilter, 2 mathematical models were made to illustrate the odour concentration on the site and in its vicinity in the most unfavorable weather conditions "Highest values" and "98th Percentile" to illustrate the concentration in the surrounding air excluding the 2% unfavorable weather condition.