Polychloroprene Degradation by Photo-Fenton. Conductivity Measures as New Approach for Detecting/Evaluation of Degradation Products

In the present work the photo-degradation of polychloroprene (PCP) in toluene solution catalyzed by FeCl₃·6H₂O and polychromatic light was investigated based on FTIR and ¹³C NMR spectroscopies, on conductivity measurements and DSC technique. The band in the 1700–1790 cm⁻¹ range in the FTIR spectrum characterized the presence of carbonyl products due to the degradation of the PCP on the solution exposed to polychromatic light. The formation of carbonyl on degraded PCP was confirmed by the presence of signal on ¹³C NMR at δ 203.5. Products of PCP degradation, such as acid chlorides, generated in the toluene solution migrate to the aqueous phase (in contact with toluene phase) and the conductivity of aqueous phase increased as the time is elapsed. The area related to the PCP melting-peak on the DSC (film casted after the PCP-FeCl₃·6H₂O toluene solution has been exposed to polychromatic light) significantly decreased in comparison to that in the DSC of the raw PCP cast film.     

Catalytic combustion of soot over ceria-zinc mixed oxides catalysts supported onto cordierite

Modified substrates as outer heterogeneous catalysts was employed to reduce the soot generated from incomplete combustion of diesel or diesel/biodiesel blends, a process that harms the environment and public health. The unique storage properties of ceria(CeO2) makes it one of the most efficient catalysts available to date. Here, we proposed that ceria-based catalysts can lower the temperature at which soot combustion occurs; more specifically, from 610℃ to values included in the diesel exhausts operation range(300–450℃). The sol-gel method was used to synthesize mixed oxide-based catalysts(CeO2:ZnO); the resulting catalysts were deposited onto cordierite substrates. In addition, the morphological and structural properties of the material were evaluated by XRD, BET, TPR-H2, and SEM. Thermogravimetric(TG/DTA) analysis revealed that the presence of the catalyst decreased the soot combustion temperature by 200℃ on average, indicating that the oxygen species arise at low temperatures in this situation, promoting highly reactive oxidation reactions. Comparative analysis of soot emission by diffuse reflectance spectroscopy(DRS) showed that catalyst-impregnated cordierite samples efficiently oxidized soot in a diesel/biodiesel stationary motor: soot emission decreased by more than 70%.     

Molecular evidence for benzo[a]pyrene and naphthalene genotoxicity in Trifolium repens L

Polycyclic aromatic hydrocarbons (PAHs) are among the most dangerous environmental contaminants due to their toxic, carcinogenic and mutagenic effects. Although there are many data in literature that detail the effects of PAHs on animals, little is known about their action on higher plants which are often used as bioindicators. The aim of the present study was to evaluate the genotoxicity of two different PAHs, benzo[a]pyrene (BaP) and naphthalene (Naph), on Trifolium repens L. Clover plants were exposed to soil which had been artificially contaminated with three concentrations of BaP (5, 10 and 20 microg g-1) or Naph (25, 50 and 100 microg g-1). After 15 days, changes in the DNA content and sequence of roots and shoots were evaluated by flow cytometry (FCM) and amplified fragment length polymorphism (AFLP). Root and shoot dry weight were also determined to assess plant growth. Results showed that BaP and Naph were both genotoxic for white clover, inducing significant changes in root and shoot DNA sequence. Damage was more severe in the root than in the shoot suggesting that the translocation of these compounds and their genotoxic metabolites was limited. Ploidy alterations were not detected and the extent of damage caused by all the tested PAH concentrations was not sufficient to affect plant development.     

UV spectra analysis for water quality monitoring in a fuel park wastewater treatment plant

In the context of the high application potentials for on-line measurements in wastewater quality monitoring, UV spectroscopy has received recent attention. In the present work UV spectrophotometric analyses were coupled to principal component analysis (PCA) and cluster analysis (CA) to characterize samples taken from a fuel park wastewater treatment plant and to attempt preliminary contaminant identification in the treated wastewater. The score plot resulting from PCA identified two different groups of spectra, one including the influents to the biological reactor and the other the treated wastewater samples. Among the latter, weekday and weekend samples could be further distinguished. The same groups of samples were identified in a dendrogram from CA. The score plot and the dendrogram also allowed the tentative identification of employed process chemicals (lubricant and detergents) as residual contaminants in the treated effluent.     

Risk Analysis and Occurrence of Hepatitis E Virus (HEV) in Domestic Swine in Northeast Brazil

Anti-HEV antibodies were detected in animals from abattoir and in farms from northeast Brazil. Our results suggest that HEV is highly disseminated in the swine population and might present a great risk to animal handlers and for consumption of raw or undercooked meat and meat products in northeast Brazil.     

Dynamics of parrotfish grazing scars

Parrotfishes exhibit a range of feeding modes. These species vary in both feeding morphology and behaviour, but the vast majority of species leave distinctive scars on the substratum when feeding. Although the role of parrotfishes in reef resilience is well documented, the basis of this role and the effect of their grazing scars on the benthic community structure remain unclear. This study evaluated the dynamics of grazing scars of large adult Scarus rivulatus and Chlorurus microrhinos on an inshore reef in the Great Barrier Reef (GBR). These species represent the most abundant scraping and excavating parrotfish species on inshore reefs. Grazing scars of each species were marked, measured and observed for seven consecutive days. S. rivulatus grazing scars were smaller in area and volume and more rapidly reoccupied by algae than those of C. microrhinos. However, because of the higher abundance and feeding frequency of S. rivulatus at the study site, this species had higher algal removal rates than C. microrhinos. These species appear to play distinctly different functional roles in shaping the benthic community of inshore GBRs. S. rivulatus is primarily responsible for algal dynamics dominated by vegetative regrowth. In contrast, C. microrhinos opens relatively large areas which remain clear for several days. These scars may represent settlement sites which are relatively free from algae and sediment. This study provides new information on the differences between scraping and excavating parrotfishes and, in a system with just one abundant large excavating species, emphasizes the potential for low functional redundancy in high diversity coral reef systems.     

Changes in the cell size of the diatom Cylindrotheca closterium in a hyperhaline pond

Cell length of the diatom Cylindrotheca closterium (Ehr.) Reimann & Lewin was investigated on a fortnightly basis from January to April 2000 in a hyperhaline pond (Sardinia, Mediterranean Sea) and relationships, with changes in temperature, salinity, and nitrite concentrations were assessed using single and multiple regression analyses. Results of our study indicate that C. closterium cell size was inversely related to temperature changes, but that salinity and nitrite concentrations may have a major idiosyncratic effect on cell size variability.     

USE AND EFFECTIVENESS OF MUNICIPAL WATER RESTRICTIONS DURING DROUGHT IN COLORADO1

ABSTRACT: Drought conditions in the summer of 2002 prompted several cities along Colorado's Front Range to enact restrictions on outdoor water use, focusing primarily on limiting the frequency of lawn watering. The different approaches utilized by eight water providers were tracked to determine the level of water savings achieved, measured as a comparison of 2002 usage to 2000 to 2001 average usage, and also based on a statistical estimate of 2002 “expected use” that accounts for the impact of drought conditions on demand. Mandatory restrictions were shown to be an effective tool for drought coping. During periods of mandatory restrictions, savings measured in expected use per capita ranged from 18 to 56 percent, compared to just 4 to 12 percent savings during periods of voluntary restrictions. As anticipated, providers with the most stringent restrictions achieved the greatest savings.