Hydrogen peroxide photolysis, fenton reagent and photo-fenton for the degradation of nitrophenols: a comparative study

The kinetics of the degradation of seven nitrophenols (2-nitrophenol, 4-nitrophenol, 2,5-dinitrophenol, 2,6-dinitrophenol, 2,4-dinitrophenol, 2-methyl-4,6-dinitrophenol, 4-methyl-2,6-dinitrophenol) with the Fenton reagent, photo-Fenton, and hydrogen peroxide photolysis was investigated. The efficiency and operating costs for the studied treatments were evaluated and compared. The Fenton reagent was found to be the most efficient and the cheapest way for the nitrophenols (NPs) degradation. The formation of nitrate as a result of mineralisation of organically bounded nitrogen was observed during the treatment of NPs with studied treatment processes. The degrees of organically bounded nitrogen conversion to nitrate after 90% degradation of NPs with the Fenton, photo-Fenton and hydrogen peroxide photolysis were 51-67%, 85-90%, and 50-60%, respectively. According to Daphnia magna acute toxicity test, the Fenton treatment led to complete detoxification of NPs.     

Reproductive biology of <Emphasis Type="Italic">Cosmasterias lurida</Emphasis> (Echinodermata: Asteroidea) an anthropogenically influenced substratum from Golfo Nuevo,Northern Patagonia (Argentina)

The starfish Cosmasterias lurida was sampled from the pier piles of Almirante Storni in the Golfo Nuevo, northern Patagonia, from November 2001 to November 2003. In this anthropogenically modified site there is an unusually abundant food supply of mussels and large aggregations of starfishes. The reproductive cycle was studied by organ indices and histological examination of gonads. The highest gonad index (GI) values were found in the summer (February–March), followed by a drop in GI values, indicating spawning. Histological analyses indicated that gametogenesis takes place from June to January, sexual maturity occurred during the summer and spawning occurred in April. The GI and pyloric caeca index (PCI) tended to have an inverse relationship, but this was only statistically significant in males. However, biochemical analyses of the starfish indicated no transfer of nutrients between pyloric caeca and gonads in either sex. In fact, simultaneous accumulation of carbohydrates was found in the pyloric caeca and gonads of both sexes.     

Seasonal variation in feeding behavior, competition and female social relationships in a forest dwelling guenon, the blue monkey (Cercopithecus mitis stuhlmanni), in the Kakamega Forest, Kenya

Socioecological models relate differences in feeding strategies to variation in the nature of female social relationships. Among the African forest guenons, females consume large quantities of fruit and other plant reproductive parts, resources which are thought to promote contest competition, yet these monkeys have been characterized as having agonistically undifferentiated relationships in which rank, if discernible at all, does not correlate with fitness benefits. To determine whether female relationships become more hierarchical under relevant ecological conditions, we monitored the adult females of two blue monkey groups (Cercopithecus mitis stuhlmanni) over a complete annual cycle in the Kakamega Forest, Kenya. Females competed aggressively for plant reproductive parts more often than any other resource type, and in both groups we detected linear dominance hierarchies. Nonetheless, agonism rates remained low throughout our study, and did not vary with changes in ecological conditions. Rather, when plant reproductive parts were scarce, subordinate females spent more time feeding and less time resting in an apparent attempt to compensate for a reduced efficiency of food intake. The effects of rank and food abundance were not reflected, however, in the distribution of grooming. The use of alternative feeding strategies appeared to blunt competition – females of all ranks were unlikely to be near others while feeding and spent more time consuming alternative resources when plant reproductive parts were scarce. The diverse diet of this species may allow females to avoid conflict so that dominance has only subtle effects that are difficult to detect. While socioecological models often simplify the connection between resources and female interactions, our results emphasize that the behavior of animals consuming particular resources, and not the resources themselves, are critical predictors of social patterns.     

Characterisation of trace elements and methylmercury in an estuarine sediment reference material, IAEA-405

An estuarine sediment sample, IAEA-405, was recently characterised for trace elements and methylmercury (MeHg) for ultimate use as a marine reference material. The reference values were calculated using data sets from 120 laboratories that participated in a world-wide intercomparison exercise. The data evaluation is highlighted, and includes comparisons of different analytical methods, as well as the distribution of data. Overall laboratory performance for this exercise was encouraging: 86 laboratories (72%) reported data with <25% outliers. There was sufficient acceptable data to establish recommended values for 17 elements and information values for a further 15 elements. In addition, a recommended value was established for methylmercury. The estuarine sediment sample, IAEA-405, can be used as a reference material for quality control in the determination of trace elements and methylmercury in moderately polluted sediments.     

Organic compounds in tire particle induce reactive oxygen species and heat-shock proteins in the human alveolar cell line A549

Debris produced from the attrition of tires of motor vehicles constitutes 5-7% of the atmospheric particulate matter (PM10). Debris particles are indeed small enough to enter human lung and thus morphological and chemical characterization has been performed. We demonstrated that the organic fraction of tire debris induces a dose-dependent increase in cell mortality, DNA damage, as well as a significant modification of cell morphology at the dose of 60 microg/ml, which may correspond to the quantity present in the air humans inhale daily. The present research aims at investigating if reactive oxygen species (ROS) production and Hsp70 expression are involved in the cascade of toxic effects produced on the A549 cell line, as it has been suggested for the ultrafine atmospheric particles and diesel exhaust. To this end, cells were exposed at the doses of 10, 50, 60, 75 microg/ml of TD organic extract (TDOE) and analyzed at different exposure time. ROS were detected by the oxidation of 2'7'-dichlorodihydrofluorescein diacetate to dichlorofluorescein, and fluorescence was measured by flow cytometry. Hsp70 protein expression was determined by immunochemical analysis, and protein expression quantification performed by optical densitometry. ROS production was analysed after 2 h of treatment. A statistically significant increase in fluorescence was observed and the intensity of the stress response was parallel to the increasing concentrations used. An evident increase of Hsp70 expression at lower doses (10, 50 microg/ml) and at longer exposure times (72 h) was observed, during the time that our previous studies showed that cell viability, plasma membrane integrity, and DNA molecules were not affected. Thus it can be deduced that the increase in Hsp70 expression protected the cells from those damages, which became evident at the higher doses, and that this parameter might be used as a sensitive indicator of exposure. These data suggest that ROS production may be the first event caused by A549 exposure to TDOE and this result is in line with other evidences provided for the role of ROS generation in ultrafine PM toxicity. It can be suggested that this event induces an overexpression of Hsp70 only at the lower doses and longer exposure time, when cells still appear unaffected. Subsequently when ROS generation reaches high levels, a general inhibition of protein synthesis probably occurs, culminating in cell toxicity.     

Acute toxicity of roundup to the nontarget organism Hyalella curvispina. Laboratory and field study

Glyphosate is the most used pesticide in Argentina. Hyalella curvispina is a widely distributed and commonly abundant component of the invertebrate assemblages in shallow waters of southern South America. The aim of this study was to assess the acute toxicity of the increasingly common Roundup Full II®, commercial formulation of the herbicide glyphosate (66.2% active ingredient), to H. curvispina in laboratory and field assessments. The mean estimated 48-h LC₅₀ of Roundup was 9.9 ± 1.7 mg L^?1. In a field experiment Roundup was applied to soybean plots. Simulated rain was generated the following day by means of irrigation sprinkler equipment. H. curvispina was exposed to runoff water and soy leaves. No mortality was observed. It is suggested that Roundup crop applications represent a low risk of acute toxicity to H. curvispina adults inhabiting water bodies adjacent to crop fields.     

The role of materials selection in the urban heat island effect in dry mid-latitude climates

This work investigates the role of materials selected for different urban surfaces (e.g. on building walls, roofs and pavements) in the intensity of the urban heat island (UHI) phenomenon. Three archetypal street-canyon geometries are considered, reflecting two-dimensional canyon arrays with frontal packing densities (λ_f) of 0.5, 0.25 and 0.125 under direct solar radiation and ground heating. The impact of radiative heat transfer in the urban environment is examined for each of the different built packing densities. A number of extreme heat scenarios were modelled in order to mimic conditions often found at low- to mid-latitudes dry climates. The investigation involved a suite of different computational fluid dynamics (CFD) simulations using the Reynolds-Averaged Navier–Stokes equations for mass and momentum coupled with the energy equation as well as using the standard k-ε turbulence model. Results indicate that a higher rate of ventilation within the street canyon is observed in areas with sparser built packing density. However, such higher ventilation rates were not necessarily found to be linked with lower temperatures within the canyon; this is because such sparser geometries are associated with higher heat transfer from the wider surfaces of road material under the condition of direct solar radiation and ground heating. Sparser canyon arrays corresponding to wider asphalt street roads in particular, have been found to yield substantially higher air temperatures. Additional simulations indicated that replacing asphalt road surfaces in streets with concrete roads (of different albedo or emissivity characteristics) can lead up to a ~5 °C reduction in the canyon air temperature in dry climates. It is finally concluded that an optimized selection of materials in the urban infrastructure design can lead to a more effective mitigation of the UHI phenomenon than the optimisation of the built packing density.     

Production of Polyhydroxyalkanoates from Fatty Wastes

The production of polyesters from triglyceride containing substrates was investigated. A first filter step based on lipase activity was followed and those bacteria potentially able to degrade oils or animal fats were further tested for their polymer accumulation properties, selected and kept for further studies. In a second step, bacteria were directly grown on animal fats and/or vegetable oils, and polyhydroxyalkanoates (PHAs) accumulation was verified under appropriate incubation conditions. Each substrate, whether of animal or vegetable derivation, supported the growth of a number of the newly isolated strains and among those, some strains were also found to produce reasonably high amounts of PHA. The repeat-unit composition of the polyesters was determined by gas chromatography (GC) analysis of the ?-hydroxyalkanoate methyl esters from the hydrolyzed polymer and some class of co-polymers were also detected. These properties, coupled with the ability of some of the selected isolates to grow and produce lipases on a minimal medium, could be considered as promising in view of possible industrial applications. The overall results indicate that PHAs could be produced from waste containing considerable amounts of fat, oil and grease (FOG), that generally need to be treated for their disposal.     

Using NDVI to Assess Vegetative Land Cover Change in Central Puget Sound

We used the Normalized Difference Vegetation Index (NDVI) in the rapidly growing Puget Sound region over three 5-year time blocks between 1986–1999 at three spatial scales in 42 Watershed Administrative Units (WAUs) to assess changes in the amounts and patterns of green vegetation. On average, approximately 20% of the area in each WAU experienced significant NDVI change over each 5-year time block. Cumulative NDVI change over 15 years (summing change over each 5-year time block) was an average of approximately 60% of each WAU, but was as high as 100% in some. At the regional scale, seasonal weather patterns and green-up from logging were the primary drivers of observed increases in NDVI values. At the WAU scale, anthropogenic factors were important drivers of both positive and negative NDVI change. For example, population density was highly correlated with negative NDVI change over 15 years (r = 0.66, P < 0.01), as was road density (r = 0.71, P < 0.01). At the smallest scale (within 3 case study WAUs) land use differences such as preserving versus harvesting forest lands drove vegetation change. We conclude that large areas within most watersheds are continually and heavily impacted by the high levels of human use and development over short time periods. Our results indicate that varying patterns and processes can be detected at multiple scales using changes in NDVIa values.