n-Octyl esters of long-chain fatty acids are not anthropogenic pollution markers

n-Octyl esters of higher fatty acids have been reported as markers of urban wastewater in sediments, polychaeta, fish, crabs and oysters (Chaler et al. in J Chromatogr A 1046:203–210, 2004)). However, up to date, there were no subsequent studies to confirm this claim. Likewise, Chaler and co-workers did not consider that the mentioned compounds might occur naturally in the environment. Here we found seven n-octyl straight-chain alkanoates, from C-20 to C-26, in the wild-growing plant Heracleum sphondylium L., Apiaceae, from 14 locations. Those plant metabolites were unambiguously identified by gas chromatographic co-injection of the synthesized esters with the inflorescence washings. All identified octyl esters represent new natural compounds, except for octyl docosanoate. Since we have demonstrated that n-octyl esters occur naturally, and in abundance, they cannot be recognized any longer as wastewater markers. Additionally, here we provide evidences that the compounds identified by Chaler et al. (2004) are in fact 2-ethylhexyl esters, mistakenly identified as n-octyl esters.     

Flexible and high-efficiency Sb2S3/solid carrier solar cell at low light intensity

Environmental Chemistry Letters - Producing green and efficient energy sources is a major challenge. As a consequence, the use of photovoltaic devices for conversion of light into electricity is...     

Enzyme activity and microorganisms diversity in soil contaminated with the Boreal 58 WG herbicide

Next-generation herbicides are relatively safe when used properly, but the recommended rates are relatively low, which can lead to overdosing. This study evaluated the responses of soil-dwelling microorganisms and soil enzymes to contamination with the Boreal 58 WG herbicide. The analyzed product contains active ingredients flufenacet and isoxaflutole. All tests were performed under laboratory conditions. The analyzed material was sandy clay. Boreal 58 WG was introduced to soil in four doses. Soil without the addition of the herbicide served as the control. The soil was mixed with the tested herbicide, and its moisture content was maintained at 50% of capillary water capacity. Biochemical and microbiological analyses were performed on experimental days 0, 20, 40, 80 and 160. Accidental contamination of soil with the Boreal 58 WG herbicide led to a relatively minor imbalance in the soil microbiological and biochemical profile. The herbicide dose influenced dehydrogenase activity in only 0.84%, urease activity in 2.04%, β-glucosidase activity in 8.26%, catalase activity in 12.40%, arylsulfatase activity in 12.54%, acid phosphatase activity in 42.11%, numbers of organotrophic bacteria in 18.29%, actinomyces counts in 1.31% and fungi counts in 6.86%.     

Influence of the organic complex concentration on adsorption of herbicide in organic modified montmorillonite

This study was undertaken to determine the impact of the organic complex concentration on the adsorption of herbicide (acetochlor) at the surface of the organic modified montmorillonite. In this work, natural montmorillonite from Bogovina (Boljevac municipality, Serbia) was used for organic modification. Cation-exchange capacity of this montmorillonite was determined using a methylene blue method (86 mmol/100 g of clay). Montmorillonite has been modified first with NaCl and then with hexadecyltrimethylammonium bromide (HDTMA-bromide) organic complex. Saturation of cation exchange capacity (CEC) was 50%, 100%, and 150%. Changes in the properties of the inorganic and organic montmorillonite have been examined using the X-ray diffraction, Fourier transform infrared spectroscopy, and batch equilibrium method. Montmorillonite modified with HDTMA-bromide demonstrated higher uptake of the herbicide, compared to the inorganic montmorillonite. Comparing the values Freundlich coefficients in batch equilibrium method, it can be seen that the adsorption of acetochlor decreased in the series: 0.5 CEC HM > 1 CEC HM > 1.5 CEC HM > NaM.     

Copper-tolerant yeasts: Raman spectroscopy in determination of bioaccumulation mechanism

Environmental Science and Pollution Research - Modern, efficient, and cost-effective approach to remediation of heavy metal-contaminated soil is based on the application of microorganisms. In this...     

Metal and metallothionein level in the heat-treated cytosol of gills of transplanted mussels Mytilus galloprovincialis Lmk

A stock of mussels Mytilus galloprovincialis was transplanted over 1 year to four sites in a semi-enclosed bay in Croatia which is under the influence of various sources of pollution. The positive correlation of metal (Cd, Zn, Cu, Mn, Fe) and metallothionein (MT) tissue contents based on the analysis of heat-treated cytosol of gills with shell mass, as an indicator of mussel age, indicated to accumulation of metals, as well as the increase of MTs with mussel age. The principal component analysis (PCA) revealed that 74% of total variance of obtained results could be explained through two principal components. The first principal component was highly correlated with MT, Cd and Zn indices (metal or MT content/shell mass), and the second one with Cu, Mn, and Fe indices, as well as the gill index. High correlation of MTs with Zn and Cd is consistent with their affinity for binding to MTs.     

On vertical distribution of tintinnines (Ciliata,Oligotrichida, Tintinnina) in the open waters of the South Adriatic

The vertical distribution of tintinnines was studied in the open sea of the South Adriatic at a station near the city of Dubrovnik (Station 12) in the period from 1979–1980 as well as at 11 stations during a cruise in January 1980. Samples were taken with the 53-m Nansen type net equipped with a closing system. The hauls were taken in 7 vertical layers. In the area investigated 72 species of tintinnines were observed. Six dominating species contributed from 30 to 93%, an average of 63% of the total numerical abundance of tintinnines. Based on the occurrence of the majority of the population of individual species going from the surface towards the sea bottom, the tintinnines have been divided into 5 groups. Most of the species (42), presenting more than 90% of the population, were found in the layer between the surface and a depth of 100 m. Other species were found in deeper layers (rarely or almost never at the surface).     

Effect of water matrices on removal of veterinary pharmaceuticals by nanofiltration and reverse osmosis membranes

This study explored the removal of five veterinary pharmaceuticals (VPs) (sulfamethoxazole (SMETOX), trimethoprim (TMP), ciprofloxacin (CIPRO), dexamethasone (DEXA) and febantel (FEBA)) from different water matrices (Milli-Q water, model water, tap water and real pharmaceutical wastewater using four types of nanofiltration (NF) membranes (NF90, NF270, NF and HL) and two reverse osmosis (RO) membranes (LFC-1 and XLE). All VPs were added to different water matrices at a concentration of 10 mg/L. Rejections of VPs and water flux were measured. The rejection increased with increase of molecular weight. The highest rejections were obtained with RO membranes (LFC-1, XLE) and tight NF (NF90) membrane. In general, the rejection of VPs was higher in model water and tap water than in Milli-Q water, but the water flux was lower. This was mainly explained by ion adsorption inside the membranes pores. Narrower pore size counteracted the effect of presence of low concentration of natural organic matter (NOM) in tap water. The NOM was assumed to enhance the adsorption of VPs onto membrane surface, increased the size exclusion and electrostatic repulsion also appeared during the transport. Investigated water matrices had influence on water flux decline due to their complexity.     

Development,Calibration and Verification of a 1-D Flow Model for a Looped River Network

This paper presents the development, calibration and verification of a looped river network model. After introducing the governing equations, the established numerical model is calibrated employing measurements conducted on the Danube River and its two main tributaries in Serbia, the Sava and Tisa rivers. The calibration is done by altering the Strickler’s coefficient using three different approaches, assigning a constant value of the coefficient in a cross section, setting the coefficient as a function of discharge and, finally, connecting the Strickler’s coefficient to local depth. The verification is conducted by comparing the computed results, for all three of the considered methods, with measurements for the time interval from January 1st to December 31st of the year 2006. Careful examination of the obtained results helped to select the most suitable calibration method for future reference. The selected approach gave better agreement of computed and measured values, has a clear physical explanation and enables faster and easier calibration.