Dioxins and furans in the atmosphere of São Paulo City, Brazil

Air samples were collected simultaneously at three urban sites in São Paulo City, Brazil, in winter, spring, summer and fall (in 2000 and 2001). Andersen PUF samplers were used for gas and particles sequential sampling. Samples were analyzed using HRGC/HRMS according to US EPA Method 8290. The greater metropolitan area of São Paulo is the largest industrialized region of Latin America and has a highly polluted atmosphere. Concentrations of dioxins and furans, which are well-known toxic chemicals, ranged from 1.14 pg m⁻³ to 13.8 pg m⁻³ (0.047 pg I-TEQ m⁻³ to 0.751 pg I-TEQ m⁻³). Principal component analysis showed that all the variables are highly correlated with one another except the 2,3,7,8-TCDD one. This is consistent with the similar concentration profiles observed for the tetra, penta, hexa, hepta and octa-homologous groups of the three sampling sites studied. At all sites, the most abundant compounds were the hepta and octa congeners. The 2,3,4,7,8-PeCDF accounted for 37–46% of the total toxicity and the 2,3,7,8-TCDD accounted for 7–16%. Highest mass concentrations of PCDD/Fs were found in the site where there is influence of industrial activities and heavy vehicular traffic fueled by gasohol, diesel, and ethanol.     

Temporal variability of airborne bacterial community structure in an urban area

Temporal airborne bacterial genetic community structure and meteorological factors were analysed above an urban area in the northwest of France from December 2003 to April 2004 with a sampling strategy considering different time intervals (from an hour to a month). Principal component analysis (PCA) of B-ARISA (Bacterial-Automated Ribosomal Intergenic Spacer Analysis) profiles revealed a hierarchy in the temporal variability of bacterial community: daily<weekly<seasonal. Co-inertia analysis between B-ARISA data and meteorological factors demonstrated the correlation between the seasonal variability in the bacterial community and climatic conditions such as temperature and relative humidity, whereas daily and weekly variability seemed likely to be managed by other factors such as anthropogenic activities.     

DNA markers indicate that distinct spawning cohorts and aggregations of Patagonian squid,<Emphasis Type="Italic"> Loligo gahi</Emphasis>, do not represent genetically discrete subpopulations

The Patagonian squid, Loligo gahi DOrbigny, has been described as having temporally and spatially identifiable spawning aggregations. Variation at six microsatellite loci was used to assess whether seasonal and geographical spawning groups around the Falkland Islands represent distinct sub-populations. Genetic variation at these loci is high in this species (mean expected heterozygosity=0.87; mean number of alleles=14.7). No evidence of significantly different allele frequencies was found, either between samples from putative spawning cohorts or geographical areas, indicating that L.gahi around the Falkland Islands comprise a single genetically homogeneous population. Age structure analysis of samples (from statolith growth increments) indicated substantial spread in hatching dates among individuals of similar size and maturity status, suggesting the potential for extensive interbreeding between seasonal cohorts. A sample of L.gahi from the SE Pacific (Peru) displayed distinctly different gene frequencies (and allele size distribution at one locus) from SW Atlantic samples, supporting the suggestion that SE Pacific and SW Atlantic populations may represent distinct subspecies.Contributed by J.P. Thorpe, Port Erin     

The effects of air pollution and meteorological parameters on respiratory morbidity during the summer in São Paulo City

Effects of meteorological variables and air pollutants on child respiratory morbidity are investigated during two consecutive summers (December-March 1992/1993 and 1993/1994) at the Metropolitan Area of S?o Paulo (MASP), Brazil. The MASP, with almost 17 million inhabitants, is considered the most populous region in South America. Due to warmer temperatures, increased rainfall and consequent low levels of air pollutants during the summer compared to winter, less attention has been paid to epidemiological studies during this season, especially in tropical urban areas such as S?o Paulo. In the present work, principal component analysis (PCA) is applied to medical end environmental data to identify patterns relating child morbidity, meteorological variables and air pollutants during the summer. The following pollutant concentrations are examined: SO2, inhalable particulate matter (PM10), and O3. The meteorological variables investigated are air temperature, water vapor (water vapor density) and solar radiation. Although low correlation between respiratory morbidity and environmental variables are, in general, observed for the entire dataset, the PCA method indicates that child morbidity is positively associated with O3 for the 1992/1993 summer. This pattern is identified in the third principal component (PC3), which explains about 19% of the total variance of all data in this summer. However, the 1993/1994 summer shows a more complex association between both groups, suggesting stronger ties with meteorological variables. Marked changes in synoptic conditions from the end of January to end of March of the 1993/1994 summer seem to have played an important role in modulating respiratory morbidity. A detailed examination of meteorological conditions in that period indicates that prefrontal (postfrontal), hot (cold) and dry (wet) days favored the observed decrease (increase) of respiratory morbidity.     

A Multimedia Chemical Fate Model with Time-Dependent Air-Water Transfer Rates

A multimedia model for the temporal evolution of the concentration of chemical species in a water basin and its bottom sediment layer has been tested with time-dependent air-water transfer rates varying with the meteorological conditions over the basin. The multimedia model uses the chemical fugacity approach in a system of two ordinary differential equations for the chemical species partition in the two mentioned media, with transfer through the sediment-water and the air-water interfaces. The air-water transfer rates are estimated by a micrometeorological preprocessor. A scenario in which known concentrations in air of a soluble pollutant (benzene) induce water and sediment pollution is tested on both synthetic (MonteCarlo-simulated) and real series of meteorological data. It is found that the use of time-dependent transfer coefficients affects not only the relaxation time, but also the long term concentration of the pollutant in water and sediment, that differs between 10 and 40% in the examined cases when compared with the same multimedia model using average constant transfer rates as usual. This is shown to be due to the statistical correlations between meteorological parameters and air pollutant concentrations, which stresses the advantages of a time-dependent estimation of the transfer coefficients. Correction terms are proposed to take into account the correlation effects when a constant parameters multimedia model is used.     

Kinship recognition and grouping in hatchling green iguanas

Summary The research addressed two questions: (1) doIguana iguana hatchlings recognize their kin, and (2) what are the recognition mechanisms? Eggs were collected from wild and captive-raised females and hatched in semi-natural incubators. In the first experiment we used eggs from two females. One of the clutches was subdivided to be placed in different incubators. Immediately after emergence one of these hatchling groups was introduced into a 10 m x 10 m enclosure. At the same time we introduced hatchlings from another female. The remaining hatchling group was kept separate for 3 weeks and was then introduced into the same cage. Unrelated hatchlings separated from each other. Related but separated hatchlings grouped according to introduction date. In the second experiment we maintained eight kin groups in individual cages and two hatchlings per kin group in an additonal cage. Hatchlings from the mixed group showed no preference for their kin before physical contact with pure kin groups had occurred. After physical contact hatchling recognized their kin by feces smell. Body odor is likely to be also involved.     

Evaluation of a novel structural model to describe the endogenous release of lead from bone

The aim of this paper was to assess the endogenous release of lead from bone to blood, in 204 exposed subjects. resuming their duties after a 10-month strike in a primary lead smelter in 1991. In vivo 109Cd K X-ray Fluorescence (109Cd K XRF) was used to measure the bone lead concentration in tibia and calcaneus in the smelter, in 1994 and five years later. The 1994 data were used to derive the post-strike bone lead concentrations retrospectively from the significant association between bone lead and the cumulative blood lead index (CBLI). When a linear model was used to predict the current blood lead upon the level of lead in bone, structural analysis of the data produced slopes for tibia (2.0, 95% CI 1.66-2.54) and calcaneus (0.19, 95% CI 0.16-0.23) that were significantly higher than those predicted by the commonly used simple linear regression method, for tibia (0.73, 95%, CI 0.58-0.88) and calcaneus (0.08, 95% CI 0.06-0.09). This suggests that more lead than previously predicted by regression is released from bone to blood. Furthermore, the structural analysis of the data produced an estimation of the contribution of the bone lead stores to the bloodstream that was more consistent with the 1999 epidemiological data than did the regression estimation. Moreover, a non-linear relationship between tibia lead and blood lead was suggested from the assumption checking procedures for regression. When a non-linear regression model was fit to the data, the method produced estimates of important parameters in human lead kinetics, namely the blood lead saturation constant, showing a good agreement with current knowledge of lead metabolism. Finally, the likelihood of a non-linear bone lead release seems to be supported by the recently described dependence of the half-life of lead in bone on age and intensity of occupational exposure.     

Petroleum Hydrocarbons Rhizodegradation by Sebastiania commersoniana (Baill.) L. B. SM. & Downs

Petroliferous activities in Brazil have an accelerated development in the last years. As a consequence, the incidence of environmental accidents such as oil spills and contamination of soils has increased significantly. Therefore, it is extremely necessary to develop remediation techniques with lower costs, decontamination efficiency and impact minimisation. The aim of this work was to evaluate Sebastiania commersoniana phytoremediation potential in soil contaminated by petroleum. This species, which is a native tree, was selected due to its proven capacity for surviving in areas contaminated by petroleum. Experiments were carried out with soils that were vegetated but non-contaminated, soils that were freshly contaminated (25, 50 and 75 g kg^?1) but non-vegetated, and soils that were vegetated and contaminated, samples were collected 60 and 424 days after contamination with the purpose of evaluating the percentage of petroleum degradation in relation to the time. The results obtained in the present study allow us to state that S. commersoniana proves to be tolerant to petroleum contamination with respect to plant’s growth. The degradation of petroleum hydrocarbons was evaluated by gas chromatography with a flame ionisation detector (GC-FID) equipped with a capillary column HP-5 (5% phenyl-methylpolysiloxane, 30 m; 0.25 mm; 0.25 μm). According to chromatographic analysis, samples in contact with S. commersoniana showed a significant area reduction of the hydrocarbon peaks. Analysis of the 60-day samples showed a reduction of petroleum hydrocarbons area higher than 60% and the 424-day samples showed a reduction higher than 94%, which demonstrates that a petroleum degradation process is occurring.     

Combining Flow Cytometry and Real-Time PCR Methodology to Demonstrate Consumption by Prymnesium parvum1

Bowers, Holly A., Andreas Brutemark, Wanderson F. Carvalho, and Edna Granéli, 2010. Combining Flow Cytometry and Real-Time PCR Methodology to Demonstrate Consumption by Prymnesium parvum. Journal of the American Water Resources Association (JAWRA) 46(1):133-143. DOI: 10.1111/j.1752-1688.2009.00397.x Abstract: Harmful algal bloom species can persist in the environment, impacting aquatic life and human health. One of the mechanisms by which some harmful algal bloom species are able to persist is by consumption of organic particles. Methods to demonstrate and measure consumption can yield insight into how populations thrive. Here, we combine flow cytometry and real-time PCR to demonstrate consumption of a cryptophyte species (Rhodomonas sp.) by a toxic mixotrophic haptophyte (Prymnesium parvum). Using flow cytometry, the feeding frequency of a population of P. parvum cells was calculated using the phycoerythrin (PE) fluorescence signal from Rhodomonas sp. and the fluorescence of an acidotropic probe labeling the food vacuoles. Feeding frequency increased in the beginning of the experiment and then began to decline, reaching a maximum of 47.5% of the whole P. parvum population after 212 min. The maximum number of consumed Rhodomonas sp. cells was 0.8 per P. parvum cell, and occurred after 114 min corresponding to an ingestion rate of 0.4 Rhodomonas sp. cells/P. parvum/h. Cells from the feeding P. parvum population were sorted, washed, and subjected to a real-time PCR assay targeting the cryptophyte 18S locus. There was a correlation between cycle threshold (Ct) values and number of consumed prey cells calculated by fluorescence. Overall, this study shows that flow cytometric analysis, of the acidotropic probe and prey pigments, is an efficient and rapid tool in enumerating food vacuoles and the number of prey cells consumed. Furthermore, we suggest that real-time PCR can be applied to cells sorted by flow cytometry, thus allowing for the detection and potential quantification of the targeted prey cells.