Mobility of arsenic, cadmium and zinc in a multi-element contaminated soil profile assessed by in-situ soil pore water sampling, column leaching and sequential extraction

Three methods for predicting element mobility in soils have been applied to an iron-rich soil, contaminated with arsenic, cadmium and zinc. Soils were collected from 0 to 30 cm, 30 to 70 cm and 70 to 100 cm depths in the field and soil pore water was collected at different depths from an adjacent 100 cm deep trench. Sequential extraction and a column leaching test in the laboratory were compared to element concentrations in pore water sampled directly from the field. Arsenic showed low extractability, low leachability and occurred at low concentrations in pore water samples. Cadmium and zinc were more labile and present in higher concentrations in pore water, increasing with soil depth. Pore water sampling gave the best indication of short term element mobility when field conditions were taken into account, but further extraction and leaching procedures produced a fuller picture of element dynamics, revealing highly labile Cd deep in the soil profile.     

Volatile carbonylic compounds in downtown Santiago, Chile

Formaldehyde, acetaldehyde, acetone, propanal, butanal, 2-butenal, 3-methylbutanal, hexanal, benzaldehyde, 2-methylbenzaldehyde, and 2,5-dimethylbenzaldehyde were measured during six spring days at downtown Santiago de Chile. Measurements were performed 24h/day and averaged over three hour periods. The averages of the maxima (ppbv) were, formaldehyde: 3.9+/-1.4; butanal: 3.3+/-3.4; acetaldehyde: 3.0+/-0.9; acetone: 2.4+/-1.0; 2-butenal: 0.56+/-0.52; propanal: 0.46+/-0.21; benzaldehyde: 0.34+/-0.3; 3-butanal: 0.11+/-0.05; hexanal: 0.11+/-0.08; 2-methylbenzaldehyde: 0.08+/-0.05; 2,5-dimethylbenzaldehyde: 0.05+/-0.03. Aliphatic aldehydes (C1-C3) are strongly correlated among them and weakly with primary (toluene) and secondary (ozone plus nitrogen dioxide or PAN) pollutants. In particular, the correlation between acetaldehyde and propanal values remains even if diurnal and nocturnal data are considered separately, indicating similar sources. All these aldehydes present maxima values in the morning (9-12h) and minima at night (0-3h). The best correlation is observed when butanal and 2-butenal data are considered (r=0.99, butanal/2-butenal=6.2). These compounds present maxima values during the 3-6h period, with minima values in the 0-3h period. These data imply a strong pre-dawn emission. Other aldehydes show different daily profiles, suggesting unrelated origins. Formaldehyde is the aldehyde whose concentration values best correlate with the levels of oxidants. The contribution of primary emissions and photochemical processes to formaldehyde concentrations were estimated by using a multiple regression. This treatment indicates that (32+/-16)% of measured values arise from direct emissions, while (79+/-23)% is attributable to secondary formation.     

Characterisation of black carbon-rich samples by <Superscript>13</Superscript>C solid-state nuclear magnetic resonance

There are difficulties in quantifying and characterising the organic matter (OM) in soils that contain significant amounts of partially oxidised char or charcoal materials. The anthropogenic black carbon (BC), such as that found in the Terra Preta de índio soils of the Amazon region, is a good example of the OM that is difficult to analyse in such soils. ¹³C direct polarisation/magic angle spinning (DP/MAS) at high MAS frequency, ¹H-¹³C cross polarisation (CP)/MAS with total suppression of spinning sidebands (TOSS), and chemical shift anisotropy (CSA) filter nuclear magnetic resonance techniques have been applied successfully for quantifying the different components of OM. However, because pyrogenic materials present strong local magnetic susceptibility heterogeneities, the use of CSA-filter and TOSS make the pulse sequences very sensitive to imperfections in the π pulses. In this study, the DP/MAS pulse sequence was replaced by a CP with a radio frequency ramp—variable amplitude CP (VACP)—VACP/MAS pulse sequence, and composite π pulses were used in the CSA-filter and TOSS pulse sequences. In that way, the component functionalities in a humic acid from a BC soil were successfully determined. The spectrometer time needed was greatly decreased by employing this VACP/MAS technique. This development provides an accurate method for characterising BC-rich samples from different origins.     

The Effect of UV-B Irradiation on the Biodegradability of Poly-β-Hydroxybutyrate (PHB) and Poly-ɛ-Caprolactone (PCL)

The biodegradability of poly--hydroxybutyrate and poly--caprolactone in soil compostage before and after irradiation of the polymers for 192, 425, and 600 h in a Weather-Ometer was examined. The biodegradability tests were done in soil compostage at pH 7.0, 9.0, and 11.0 to assess the influence of this parameter on degradation. The rate of degradation was directly proportional to the soil alkalinity. Poly--hydroxybutyrate showed the greatest weight loss and aging in a Weather-Ometer did not significantly increase the biodegradation, except when the polymer was aged for 425 h and buried in soil compostage of pH 11.0.     

210Po concentration in Perna perna mussels: looking for radiation effects

Twenty ropes with 400 Perna perna mussels seeds (3 cm shell size) were set-up on floating structures at Cabo Frio Island, Arraial do Cabo, approximately 100 km northeast of Rio de Janeiro city. A rope was taken out on a monthly basis, and the shell sizes of 100 seeds were measured. The haemolymph of 10 male and 10 female individuals was taken, and the same individuals were separated for 210Po/210Pb determination. After one year of monthly sampling, no clear correlation was observed between the 210Po concentration, mussel's age and weight. A mean 210Po concentration of 155 Bq kg(-1) wet weight basis, was obtained, which is comparable with data reported in the literature. The radiation dose did not have any observable effect on the micronuclei frequency and DNA breaks in the mussels. This was probably due to the low dose rate, 0.02 mGy d(-1), in comparison with the suggested potential dose limit of 10 mGy d(-1).     

Influences of moonlight,ambient temperature,and food availability on the diurnal and nocturnal activity of owl monkeys (<Emphasis Type="Italic">Aotus azarai</Emphasis>)

The study of activity rhythms, their potential zeitgebers and masking factors among free-ranging primates has received relatively little attention in the past. Most primates are diurnal, a few of them nocturnal, and even fewer are cathemeral. Owl monkeys (Aotus azarai azarai) regularly show diurnal, as well as nocturnal, activity in the Argentinean and Paraguayan Chaco. The goal of this study was to examine how changes in activity patterns in owl monkeys of Formosa, Argentina are related to daily, monthly, and seasonal changes in temperature, light and food availability . During 1 year, I collected activity data from five groups followed continuously from dawn to dusk, dusk to dawn or uninterruptedly during 24 or 36 h for approximately 1,500 h. I kept hourly and daily records of temperature and light conditions, and I gathered monthly information on the density, distribution and abundance of food resources available to the monkeys. I found that the area of study is highly seasonal, and characterized by significant fluctuations in rainfall, temperature, photoperiod, and food availability. Owl monkeys had on average 5 h of activity during the day and 4 h during the night. The amount of diurnal activity remained fairly constant through the year despite seasonal changes in exogenous factors. Owl monkeys did not show changes in their activity patterns that could be attributed to changes in food availability. Nocturnal activity increased as the amount of moonlight increased, whereas diurnal activity decreased following a full-moon night. Ambient temperature was a good predictor of activity only when the moon was full. These results argue convincingly for an interaction between ambient temperature and moonlight in determining the observed activity pattern. It is then highly advisable that any evaluation of diurnal activity in cathemeral animals be analyzed controlling for the possible effects of moonlight during the previous night.Communicated by P. Kappeler     

Ovarian maturation of the multi-spawning spider crab <Emphasis Type="Italic">Maja brachydactyla</Emphasis> (Decapoda: Majidae) with special reference to yolk formation

In the study of the reproductive biology of the spider crab Maja brachydactyla, the morphology of the female reproductive system and yolk formation have long been overlooked. Females spawn two or three times during their annual reproductive cycle in northern Spain (Galicia). The ovaries consist of two lobes. The right and left lobes are connected by a small cross-lobe at the level of the heart and merge at the posterior edge. Before merging, the ovaries descend to the ventral part of the body, joining the spermathecae in the vagina, which opens through a chitin tube to the gonopore, located in the sternite, at the level of the third walking leg. No morphological changes have been observed between either the different parts of the ovaries or the different annual spawning periods. At the start of vitellogenesis, the oocyte of M. brachydactyla is characterized by a large number of vesicles in the cytoplasm. These vesicles are surrounded by a unit membrane whose size increases as the oocyte matures and contain fine granular material including a variable number of ovoid, electron-dense granules. The vesicles are of diverse origin, although most of them develop directly from the mitochondria and the Golgi complex (endogenous phase of vitellogenesis). In a subsequent phase, a series of substances (principally lipoproteins) are incorporated into the ooplasma by means of micropinocytosis. These substances are also involved in yolk formation (exogenous phase of vitellogenesis). During vitellogenesis in M. brachydactyla, mitochondria play the most important role since they are not only the energetic centre of the cellule, but they also act as containers of high-energy reserve substances: the yolk granules.