Natural attenuation of petroleum hydrocarbons—a study of biodegradation effects in groundwater (Vitanovac,Serbia)

The role of natural attenuation processes in groundwater contamination by petroleum hydrocarbons is of intense scientific and practical interest. This study provides insight into the biodegradation effects in groundwater at a site contaminated by kerosene (jet fuel) in 1993 (Vitanovac, Serbia). Total petroleum hydrocarbons (TPH), hydrochemical indicators (O₂, NO₃^?, Mn, Fe, SO₄^2?, HCO₃^?), δ¹³C of dissolved inorganic carbon (DIC), and other parameters were measured to demonstrate biodegradation effects in groundwater at the contaminated site. Due to different biodegradation mechanisms, the zone of the lowest concentrations of electron acceptors and the zone of the highest concentrations of metabolic products of biodegradation overlap. Based on the analysis of redox-sensitive compounds in groundwater samples, redox processes ranged from strictly anoxic (methanogenesis) to oxic (oxygen reduction) within a short distance. The dependence of groundwater redox conditions on the distance from the source of contamination was observed. δ¹³C values of DIC ranged from ??15.83 to ??2.75‰, and the most positive values correspond to the zone under anaerobic and methanogenic conditions. Overall, results obtained provide clear evidence on the effects of natural attenuation processes—the activity of biodegradation mechanisms in field conditions.     

Influence of long-term consumption of bitter apricot seeds on risk factors for cardiovascular diseases

The present study was designed to reveal whether long-term consumption of bitter apricot seeds causes changes in lipid profile and other risk factors for cardiovascular diseases. The study group consisted of 12 healthy adult volunteers (5 females and 7 males). The average age of women was 41.60 ± 11.28 years and the average age of men was 36.71 ± 13.70 years. Volunteers consumed 60 mg kg^?1 of body weight of bitter apricot seeds divided into 8–12 doses daily for 12 weeks. Volunteers were recruited from the general population of Slovak Republic. After 12 weeks, mean body weight of the participants increased from 77.34 to 78.22 kg (P > 0.05). The average total cholesterol levels decreased from 4.86 mmol L^?1 at the beginning of the study to 4.44 mmol L^?1 at the end of the study (P < 0.05). We did not observe any significant increase in high-density cholesterol (from 1.55 to 1.60 mmol L^?1). The average low-density cholesterol levels decreased from 2.93 mmol L^?1 at the beginning of the study to 2.31 mmol L^?1 at the end of the study (P < 0.001). Concentration of triglycerides increased significantly over the 12-week intervention period from 0.84 to 1.17 mmol L^?1. After the intervention, the high-sensitivity C-reactive protein level decreased from 1.92 to 1.23 mg L^?1, but results were non-significant (P > 0.05). Creatine kinase serum levels increased from 2.31 to 2.77 mg L^?1 (P > 0.05) over the 12-week intervention period. The results suggest that regular intake of bitter apricot seeds may be considered potentially useful for prevention of cardiovascular diseases.     

Residual Effect of Induced Water Stress and Nitrogen Addition on the Mycobiota in Scots Pine Stands

Mycobiota (fungi, lichens and myxomycetes) was examined in permanent plots following experiments of artificial drought (D) and nitrogen addition (N) and compared with untreated forest (C), in Scots pine stand planted on Arenosols. Species diversity and relationships between fungal community structure and environmental variables (plant species numbers and cover, bryophyte cover, soil and bark pH, tree mortality) were explored. Both D and N treatments lead to decrease of fungal species in general, however, responses of individual trophic and ecological groups varied. The strongest effect of the treatments was observed for soil fungi, especially mycorrhizal: numbers of fruiting species and ectomycorrhizal root tips decreased, and species composition has changed. Saprotrophic fungi reacted by changes in species composition but not in numbers. Of the studied environmental variables, the most significant effect on mycobiota had bryophyte and vascular plant cover as well as vascular plant species numbers.     

哈希在线分析仪在石化废水COD测定中的应用

介绍了美国哈希公司COD在线分析仪的工作原理、仪器结构与测量步骤,以及在中石化金陵分公司污染源在线监测系统中的应用.分析了仪器常见故障产生的原因与排除方法,提出应注重仪器的日常运行检查,采取相应的质量控制措施,确保自动监测数据的有效性.     

The first survey of airborne trace elements at airport using moss bag technique

Environmental Science and Pollution Research - Air traffic represents an important way of social mobility in the world, and many ongoing discussions are related to the impacts that air...     

Review of efficiencies of cogeneration units using internal combustion engines

The most frequently used technology in cogeneration units up to 10 MWe are internal combustion engines and the majority of the models are up to 500 kWe. There are dozens of reciprocating internal combustion engine–based cogeneration unit manufacturers and more than hundred suppliers in the market. In the article, data from supplier technical specifications of 583 units (34 manufacturers) is collected and analyzed. The authors proposed mathematical relations that show dependence of efficiencies on electric power that can be used for initial feasibility studies. Authors also have showed that value of 0.75 for power-to-heat ratio (proposed by EU Directive 2004/8/EC) does not always correspond to current market situation.     

Evaluation of potential genotoxic/cytotoxic effects induced by epoxiconazole and fenpropimorph-based fungicide in bovine lymphocytes in vitro

Potential genotoxic/cytotoxic effects of the epoxiconazole/fenpropimorph-based fungicide were investigated using single cell gel electrophoresis and cytogenetic assays: chromosomal aberrations, sister chromatid exchanges, micronuclei and fluorescence in situ hybridization in cultured bovine lymphocytes. No statistically significant elevations of DNA damage and increases in cytogenetic endpoints were seen. However, evident cytotoxic effect presented as a decrease in mitotic and proliferation indices were recorded after exposure of bovine lymphocytes to the fungicide for 24 and 48 h at concentrations ranging from 3 to 15 µg mL^?1 (P < 0.05, P < 0.01, P < 0.001). Similarly, for 24 h an inhibition in the cytokinesis block proliferation index (CBPI) was obtained after exposure to the fungicide at concentrations ranging from 1.5 to 15 µg mL^?1 (P < 0.01, P < 0.001) in each donor.     

Pure non-dioxin-like PCB congeners suppress induction of AhR-dependent endpoints in rat liver cells

The relative potencies of non-ortho-substituted coplanar polychlorinated biphenyl (PCB) congeners to activate the aryl hydrocarbon receptor (AhR) and to cause the AhR-dependent toxic events are essential for their risk assessment. Since some studies suggested that abundant non-dioxin-like PCB congeners (NDL-PCBs) may alter the AhR activation by PCB mixtures and possibly cause non-additive effects, we evaluated potential suppressive effects of NDL-PCBs on AhR activation, using a series of 24 highly purified NDL-PCBs. We investigated their impact on the model AhR agonist-induced luciferase reporter gene expression in rat hepatoma cells and on induction of CYP1A1/1B1 mRNAs and deregulation of AhR-dependent cell proliferation in rat liver epithelial cells. PCBs 128, 138, and 170 significantly suppressed AhR activation (with IC₅₀ values from 1.4 to 5.6 μM), followed by PCBs 28, 47, 52, and 180; additionally, PCBs 122, 153, and 168 showed low but still significant potency to reduce luciferase activity. Detection of CYP1A1 mRNA levels in liver epithelial cells largely confirmed these results for the most abundant NDL-PCBs, whereas the other AhR-dependent events (CYP1B1 mRNA expression, induction of cell proliferation in confluent cells) were less sensitive to NDL-PCBs, thus indicating a more complex regulation of these endpoints. The present data suggest that some NDL-PCBs could modulate overall dioxin-like effects in complex mixtures.     

Influence of selected anti-cancer drugs on the induction of DNA double-strand breaks and changes in gene expression in human hepatoma HepG2 cells

In chemotherapy, various anti-cancer drugs with different mechanisms of action are used and may represent different risk of undesirable delayed side effects in treated patients as well as in occupationally exposed populations. The aim of the present study was to evaluate genotoxic potential of four widely used anti-cancer drugs with different mechanisms of action: 5-fluorouracil (5-FU), cisplatin (CDDP) and etoposide (ET) that cause cell death by targeting DNA function and imatinib mesylate (IM) that inhibits targeted protein kinases in cancer cells in an experimental model with human hepatoma HepG2 cells. After 24 h of exposure all four anti-cancer drugs at non-cytotoxic concentrations induced significant increase in formation of DNA double strand breaks (DSBs), with IM being the least effective. The analysis of the changes in the expression of genes involved in the response to DNA damage (CDKN1A, GADD45A, MDM2), apoptosis (BAX, BCL2) and oncogenesis (MYC, JUN) showed that 5-FU, CDDP and ET upregulated the genes involved in DNA damage response, while the anti-apoptotic gene BCL2 and oncogene MYC were downregulated. On the contrary, IM did not change the mRNA level of the studied genes, showing different mechanism of action that probably does not involve direct interaction with DNA processing. Genotoxic effects of the tested anti-cancer drugs were observed at their therapeutic concentrations that may consequently lead to increased risk for development of delayed adverse effects in patients. In addition, considering the genotoxic mechanism of action of 5-FU, CDDP and ET an increased risk can also not be excluded in occupationally exposed populations. The results also indicate that exposure to 5-FU, CDDP and ET represent a higher risk for delayed effects such as cancer, reproductive effects and heritable disease than exposure to IM.     

Metal contamination of short-term snow cover near urban crossroads: correlation analysis of metal content and fine particles distribution

Snow samples were collected near crossroads in Novi Sad, Serbia, during December 2009 to assess metal concentrations (Ca, K, Zn, Fe, Cu, Mn, Al, Pb and Na), fine particle distribution and pH value. The filtered samples of melted snow were analysed, with a focus on particles smaller than a few μm. The most common values of the frequency number distribution curve were either in the range of 0.05-0.07 μm or one order of magnitude higher (0.2-0.5 μm). At examined locations metal concentrations varied from 0.0004 mg L⁻¹ for Pb to 18.9 mg L⁻¹ for Na. Besides Na, which mostly originated from de-icing salt, Ca is found to be the most abundant element in snow indicating the dominant influence of natural factors on snow chemistry. No significant difference was found in concentration of the elements at locations near crossroads with either low or high traffic volume, except for Na and Zn.To investigate how metals were related a correlation analysis was done for the concentrations of metals and with respect to the particle size distribution parameters and pH values. The major influence on the fine particle volume (mass) was concluded to be due to the elements from anthropogenic sources. This conclusion was based on the significant positive correlation between Fe, Zn and Al and the fine particle volume based distribution parameters.