Radio (<Superscript>14</Superscript>C)- and fluorescent-doubly labeled silica nanoparticles for biological and environmental toxicity assessment

A new and efficient synthetic route to fluorescent and ¹⁴C-double-labeled silica-based nanoparticles (NPs) is described. The synthesis has been carried out using the “oil-in-water” micro-emulsion technique. Fluorescent and radioactive labeling have been achieved entrapping labeled poly(ethylene glycol) (PEG) molecules in the NPs. The produced particles have been analyzed by means of scanning electron microscopy, photon correlation spectroscopy, confocal microscopy, scintillation counting and oxidation/combustion experiments. Fluorescence quenching experiments confirm that the label is entrapped in the particles. The results presented suggest that the silica matrix does not block the β-radiations emitted from the labeled PEG molecules entrapped in the NPs.     

The utility of electrocardiography and echocardiography in copper deficiency-induced cardiac damage in goats

Environmental Science and Pollution Research - Copper deficiency (CuD) is a common mineral disorder in ruminants, which causes histomorphological changes in the heart due to disturbances in...     

Humic-like substances extracted from composts can promote the photodegradation of Irgarol 1051 in solar light

Humic-like substances (HLS) were extracted from a mixture of sewage sludges and trimmings (70-30%, w/w) after different times of composting (0, 70 days and 130 days). HLS were analyzed by elemental analysis, UV-visible and fluorescence spectroscopy and also tested for their ability to photosensitize the degradation of Irgarol. The rate of Irgarol photodegradation in artificial solar light was found to be 2.5- to 4.3-fold higher in the presence of HLS than in buffered Milli-Q water. These results were confirmed by experiments in solar light that evidenced the photodegrading properties of HLS in a more striking way. Using 2-propanol as hydroxyl radical scavenger, we could show that hydroxyl radicals contributed to the photosensitized Irgarol degradation for about 25%. The photodegrading activity of HLS, their absorbance and their emissive properties were all found to increase between 0 and 70 days of composting and to remain quite constant between 70 and 130 days. The degree of humification varied in the same way, linking all these properties to the humification process.     

Lake Water Levels and Associated Hydrologic Characteristics in the Conterminous U.S.

Establishing baseline hydrologic characteristics for lakes in the United States (U.S.) is critical to evaluate changes to lake hydrology. We used the U.S. Environmental Protection Agency National Lakes Assessment 2007 and 2012 surveys to assess hydrologic characteristics of a population of ~45,000 lakes in the conterminous U.S. based on probability samples of ~1,000 lakes/yr distributed across nine ecoregions. Lake hydrologic study variables include water‐level drawdown (i.e., vertical decline and horizontal littoral exposure) and two water stable isotope‐derived parameters: evaporation‐to‐inflow (E:I) and water residence time. We present (1) national and regional distributions of the study variables for both natural and man‐made lakes and (2) differences in these characteristics between 2007 and 2012. In 2007, 59% of the population of U.S. lakes had Greater than normal or Excessive drawdown relative to water levels in ecoregional reference lakes with minimal human disturbances; whereas in 2012, only 20% of lakes were significantly drawn down beyond normal ranges. Water isotope‐derived variables did not differ significantly between survey years in contrast to drawdown. Median E:I was 20% indicating that flow‐through processes dominated lake water regimes. For 75% of U.S. lakes, water residence time was less than one year and was longer in natural vs. man‐made lakes. Our study provides baseline ranges to assess local and regional lake hydrologic status and inform management decisions in changing environmental conditions.     

Cytotoxic effects of seven Tunisian hospital wastewaters on the proliferation of human breast cancer cell line MDA-231: correlation with their chemical characterization

Environmental Science and Pollution Research - Hospital wastewaters contain large amounts of pharmaceutical residues, which may eventually be discharged into the aquatic environment through...     

Occurrence of virulence genes among Vibrio cholerae and Vibrio parahaemolyticus strains from treated wastewaters

Pathogenic Vibrio species are an important cause of foodborne illnesses. The aim of this study was to describe the occurrence of potentially pathogenic Vibrio species in the final effluents of a wastewater treatment plant and the risk that they may pose to public health. During the 1-year monitoring, a total of 43 Vibrio strains were isolated: 23 Vibrio alginolyticus, 1 Vibrio cholerae, 4 Vibrio vulnificus, and 15 Vibrio parahaemolyticus. The PCR investigation of V. parahaemolyticus and V. cholerae virulence genes (tlh, trh, tdh, toxR, toxS, toxRS, toxT, zot, ctxAB, tcp, ace, vpi, nanH) revealed the presence of some of these genes in a significant number of strains. Intraspecies variability and genetic relationships among the environmental isolates were analyzed by random amplified polymorphic DNA-PCR (RAPD-PCR). We report the results of the first isolation and characterization of an environmental V. cholerae non-O1 non-O139 and of a toxigenic V. parahaemolyticus strain in Tunisia. We suggest that non-pathogenic Vibrio might represent a marine reservoir of virulence genes that can be transmitted between strains by horizontal transfer.     

Thermal,physical, mechanical and microstructural properties of dredged sediment-based ceramic tiles as substituent of kaolin

Environmental Science and Pollution Research - The aim of this study was to recycle dredged sediments as an alternative raw material in the production of ceramic tiles. The effect of the...